153 results on '"Bhatta, Gopal"'
Search Results
2. Gamma-ray Blazar Classification using Machine Learning with Advanced Weight Initialization and Self-Supervised Learning Techniques
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Bhatta, Gopal, Gharat, Sarvesh, Borthakur, Abhimanyu, and Kumar, Aman
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Machine learning has emerged as a powerful tool in the field of gamma-ray astrophysics. The algorithms can distinguish between different source types, such as blazars and pulsars, and help uncover new insights into the high-energy universe. The Large Area Telescope (LAT) on-board the Fermi Gamma-ray telescope has significantly advanced our understanding of the Universe. The instrument has detected a large number of gamma-ray emitting sources, among which a significant number of objects have been identified as active galactic nuclei (AGN). The sample is primarily composed of blazars; however, more than one-third of these sources are either of an unknown class or lack a definite association with a low-energy counterpart. In this work, we employ multiple machine learning algorithms to classify the sources based on their other physical properties. In particular, we utilized smart initialisation techniques and self-supervised learning for classifying blazars into BL Lacertae objects (BL Lac) and flat spectrum radio quasars (FSRQ). The core advantage of the algorithm is its simplicity, usage of minimum number of features and easy deployment due to lesser number of parameters without compromising on the performance. The model predicts that out of the 1115 sources of uncertain type in the 4FGL-DR3 catalog, 820 can be classified as BL Lacs, and 295 can be classified as FSRQs., Comment: Accepted at MNRAS, Comments are appreciated
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- 2023
3. Estimation of redshift and associated uncertainty of Fermi/LAT extra-galactic sources with Deep Learning
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Gharat, Sarvesh, Borthakur, Abhimanyu, and Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
With the advancement of technology, machine learning-based analytical methods have pervaded nearly every discipline in modern studies. Particularly, a number of methods have been employed to estimate the redshift of gamma-ray loud active galactic nuclei (AGN), which are a class of supermassive black hole systems known for their intense multi-wavelength emissions and violent variability. Determining the redshifts of AGNs is essential for understanding their distances, which, in turn, sheds light on our current understanding of the structure of the nearby universe. However, the task involves a number of challenges such as the need for meticulous follow-up observations across multiple wavelengths and astronomical facilities. In this study, we employ a simple yet effective deep learning model with a single hidden layer having $64$ neurons and a dropout of 0.25 in the hidden layer, on a sample of AGNs with known redshifts from the latest AGN catalog, 4LAC-DR3, obtained from Fermi-LAT. We utilized their spectral, spatial, and temporal properties to robustly predict the redshifts of AGNs as well quantify their associated uncertainties, by modifying the model using two different variational inference methods. We achieve a correlation coefficient of 0.784 on the test set from the frequentist model and 0.777 and 0.778 from both the variants of variational inference, and, when used to make predictions on the samples with unknown redshifts, we achieve mean predictions of 0.421, 0.415 and 0.393, with standard deviations of 0.258, 0.246 and 0.207 from the models, respectively., Comment: Accepted: MNRAS
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- 2023
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4. Constraining X-ray variability of the blazar 3C 273 using XMM-Newton observations over two decades
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Dinesh, Adithiya, Bhatta, Gopal, Adhikari, Tek P., Mohorian, Maksym, Dhital, Niraj, Chaudhary, Suvas C., Panis, Radim, and Gora, Dariusz
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Blazars exhibit relentless variability across diverse spatial and temporal frequencies. The study of long- and short-term variability properties observed in the X-ray band provides insights into the inner workings of the central engine. In this work, we present timing and spectral analyses of the blazar 3C 273 using the X-ray observations from the $\textit{XMM-Newton}$ telescope covering the period from 2000 to 2020. The methods of timing analyses include estimation of fractional variability, long- and short-term flux distribution, rms-flux relation, and power spectral density analysis. The spectral analysis include estimating a model independent flux hardness ratio and fitting the observations with multiplicative and additive spectral models such as \textit{power-law}, \textit{log-parabola}, \textit{broken power-law}, and \textit{black body}. The \textit{black body} represents the thermal emission from the accretion disk, while the other models represent the possible energy distributions of the particles emitting synchrotron radiation in the jet. During the past two decades, the source flux changed by of a factor of three, with a considerable fractional variability of 27\%. However, the intraday variation was found to be moderate. Flux distributions of the individual observations were consistent with a normal or log-normal distribution, while the overall flux distribution including entire observations appear to be rather multi-modal and of a complex shape. The spectral analyses indicate that \textit{log-parabola} added with a \textit{black body} gives the best fit for most of the observations. The results indicate a complex scenario in which the variability can be attributed to the intricate interaction between the disk/corona system and the jet., Comment: 18 pages, 8 figures, ApJ accepted
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- 2023
5. Profound optical flares from the relativistic jets of active galactic nuclei
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Bhatta, Gopal, Zola, Staszek, Drozdz, M., Reichart, Daniel, Haislip, Joshua, Kouprianov, Vladimir, Matsumoto, Katsura, Sonbas, Eda, Caton, D., Pajdosz-Śmierciak, Urszula, Simon, A., Provencal, J., Góra, Dariusz, and Stachowski, Grzegorz
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Intense outbursts in blazars are among the most extreme phenomena seen in extragalactic objects. Studying these events can offer important information about the energetic physical processes taking place within the innermost regions of blazars, which are beyond the resolution of current instruments. This work presents some of the largest and most rapid flares detected in the optical band from the sources 3C 279, OJ 49, S4 0954+658, Ton 599, and PG 1553+113, which are mostly TeV blazars. The source flux increased by nearly ten times within a few weeks, indicating the violent nature of these events. Such energetic events might originate from magnetohydrodynamical instabilities near the base of the jets, triggered by processes modulated by the magnetic field of the accretion disc. We explain the emergence of flares owing to the injection of high-energy particles by the shock wave passing along the relativistic jets. Alternatively, the flares may have also arisen due to geometrical effects related to the jets. We discuss both source-intrinsic and source-extrinsic scenarios as possible explanations for the observed large amplitude flux changes., Comment: 8 pages, 2 figures, 38th International Cosmic Ray Conference (ICRC2023) proceedings
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- 2023
6. A Stochastic Approach To Reconstruct Gamma Ray Burst Lightcurves
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Dainotti, Maria G., Sharma, Ritwik, Narendra, Aditya, Levine, Delina, Rinaldi, Enrico, Pollo, Agnieszka, and Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Gamma-Ray Bursts (GRBs), being observed at high redshift (z = 9.4), vital to cosmological studies and investigating Population III stars. To tackle these studies, we need correlations among relevant GRB variables with the requirement of small uncertainties on their variables. Thus, we must have good coverage of GRB light curves (LCs). However, gaps in the LC hinder the precise determination of GRB properties and are often unavoidable. Therefore, extensive categorization of GRB LCs remains a hurdle. We address LC gaps using a 'stochastic reconstruction,' wherein we fit two pre-existing models (Willingale 2007; W07 and Broken Power Law; BPL) to the observed LC, then use the distribution of flux residuals from the original data to generate data to fill in the temporal gaps. We also demonstrate a model-independent LC reconstruction via Gaussian Processes. At 10% noise, the uncertainty of the end time of the plateau, its correspondent flux, and the temporal decay index after the plateau decreases, on average, by 33.3% 35.03%, and 43.32%, respectively for the W07, and by 33.3%, 30.78%, 43.9% for the BPL. The slope of the plateau decreases by 14.76% in the BPL. After using the Gaussian Process technique, we see similar trends of a decrease in uncertainty for all model parameters for both the W07 and BPL models. These improvements are essential for the application of GRBs as standard candles in cosmology, for the investigation of theoretical models and for inferring the redshift of GRBs with future machine learning analysis., Comment: 20 pages, 6 tables, 11 figures
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- 2023
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7. Multi-band optical variability of a newly discovered twelve blazars sample from 2013-2019
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Jovanovic, Miljana D., Damljanovic, Goran, Taris, Francois, Gupta, Alok C., and Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Here we present the first optical photometric monitoring results of a sample of twelve newly discovered blazars from the ICRF - Gaia CRF astrometric link. The observations were performed from April 2013 until August 2019 using eight telescopes located in Europe. For a robust test for the brightness and colour variability, we use Abbe criterion and F-test. Moreover, linear fittings are performed to investigate the relation in the colour-magnitude variations of the blazars. Variability was confirmed in the case of 10 sources; two sources, 1429+249 and 1556+335 seem to be possibly variable. Three sources (1034+574, 1722+119, and 1741+597) have displayed large amplitude brightness change of more than one magnitude. We found that the seven sources displayed bluer-when-brighter variations, and one source showed redder-when-brighter variations. We briefly explain the various AGN emission models which can explain our results., Comment: 14 pages, 8 figures, 11 tables, 6 supplement figures can be provided on request, MNRAS in press
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- 2023
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8. Catching profound optical flares in blazars
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Bhatta, Gopal, Zola, Staszek, Drozdz, M., Reichart, Daniel, Haislip, Joshua, Kouprianov, Vladimir, Matsumoto, Katsura, Sonbas, Eda, Caton, D., Pajdosz-Śmierciak, Urszula, Simon, A., Provencal, J., Góra, Dariusz, and Stachowski, Grzegorz
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Flaring episodes in blazars represent one of the most violent processes observed in extra-galactic objects. Studies of such events shed light on the energetics of the physical processes occurring in the innermost regions of blazars, which cannot otherwise be resolved by any current instruments. In this work, we present some of the largest and most rapid flares captured in the optical band in the blazars 3C 279, OJ 49, S4 0954+658, TXS 1156+295 and PG 1553+113. The source flux was observed to increase by nearly ten times within a timescale of a few weeks. We applied several methods of time series analysis and symmetry analysis. Moreover, we also performed searches for periodicity in the light curves of 3C 279, OJ 49 and PG 1553+113 using the Lomb-Scargle method and found plausible indications of quasi-periodic oscillations (QPOs). In particular, the 33- and 22-day periods found in 3C 279, i.e. a 3:2 ratio, are intriguing. These violent events might originate from magnetohydrodynamical instabilities near the base of the jets, triggered by processes modulated by the magnetic field of the accretion disc. We present a qualitative treatment as the possible explanation for the observed large amplitude flux changes in both the source-intrinsic and source-extrinsic scenarios., Comment: 11 pages, 6 figures, MNRAS accepted
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- 2023
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9. Exploring Short-Term Optical Variability of Blazars Using $\textit{TESS}$
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Pininti, Vivek Reddy, Bhatta, Gopal, Paul, Sagarika, Kumar, Aman, Rajgor, Aayushi, Barnwal, Rahul, and Gharat, Sarvesh
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present a first systematic time series study of a sample of blazars observed by the Transiting Exoplanet Survey Satellite $\textit{TESS}$ spacecraft. By cross matching the positions of the sources in the TESS observations with those from Roma-BZCAT, 29 blazars including both BL Lacerate objects and flat-spectrum radio quasars were identified. The observation lengths of the 79 light curves of the sources, across all sectors on which the targets of interest have been observed by $\textit{TESS}$, range between 21.25 and 28.2 days. The light curves were analyzed using various methods of time series analysis. The results show that the sources exhibit significant variability with fractional variability spanning between 1.41% and 53.84%. The blazar flux distributions were studied by applying normal and lognormal probability density function models. The results indicate that optical flux histogram of the sources are consistent with normal probability density function with most of them following bi-modal distribution as opposed to uni-modal distribution. This suggests that the days-timescale optical variability is contributed either by two different emission zones or two distinct states of short-term activity in blazars. Power spectral density analysis was performed by using the power spectral response method and the true power spectra of unevenly sampled light curves were estimated. The power spectral slopes of the light curves ranged from 1.7 to 3.2., Comment: Accepted to MNRAS
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- 2022
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10. Blazar jets as possible sources of ultra-high energy photons: a short review
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Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
In this work, I present a qualitative discussion on the prospect of production of ultra-high photons in blazars. The sources are a subclass of active galactic nuclei which host supermassive black holes and fire relativistic jets into the intergalactic medium. The kpc scale jets are believed to be dominated by Poynting flux and constitute one of the most efficient cosmic particle accelerators, that potentially are capable of accelerating the particles up to EeV energies. Recent IceCube detection of astrophysical neutrino emission in coincidence with the enhanced gamma-ray from Tev blazar TXS 0506 + 056 further supports hadronic models of blazar emissions in which particle acceleration processes such as relativistic shocks, magnetic re-connection, and relativistic turbulence could energize hardrons, e. g. protons, up to energies equivalent to billions of Lorentz factors. The ensuing photo-pionic processes may then result in gamma-rays accompanied by neutrino flux. Furthermore, the fact that blazars are the dominant source of observed TeV emission encourages us to search for signatures of acceleration scenarios that would lead to the creation of ultra-high energy photons., Comment: 8 pages, accepted for MDPI Universe Special Issue "Ultra High Energy Photons"
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- 2022
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11. Rapid X-ray Variability in Mkn 421 during a Multiwavelength Campaign
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Markowitz, Alex G., Nalewajko, Krzysztof, Bhatta, Gopal, Dewangan, Gulab C., Chandra, Sunil, Dorner, Daniela, Schleicher, Bernd, Pajdosz-Smierciak, Urszula, Stawarz, Lukasz, Zola, Staszek, Ostrowski, Michal, Carosati, Daniele, Krishnan, Saikruba, Bachev, Rumen, Benitez, Erika, Gazeas, Kosmas, Hiriart, David, Hu, Shao-Ming, Larionov, Valeri, Marchini, Alessandro, Matsumoto, Katsura, Nikiforova, A. A., Pursimo, Tapio, Raiteri, Claudia M., Reichart, Daniel E., Rodriguez, Diego, Semkov, Evgeni, Strigachev, Anton, Sugiura, Yuki, Villata, Massimo, Webb, James R., Arbet-Engels, Axel, Baack, Dominik, Balbo, Matteo, Biland, Adrian, Bretz, Thomas, Buss, Jens, Eisenberger, Laura, Elsaesser, Dominik, Hildebrand, Dorothee, Iotov, Roman, Kalenski, Adelina, Mannheim, Karl, Mitchell, Alison, Neise, Dominik, Noethe, Maximilian, Paravac, Aleksander, Rhode, Wolfgang, Sliusar, Vitalii, and Walter, Roland
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
The study of short-term variability properties in AGN jets has the potential to shed light on their particle acceleration and emission mechanisms. We report results from a four-day coordinated multi-wavelength campaign on the highly-peaked blazar (HBL) Mkn 421 in 2019 January. We obtained X-ray data from AstroSAT, BVRI photometry with the Whole Earth Blazar Telescope (WEBT), and TeV data from FACT to explore short-term multi-wavelength variability in this HBL. The X-ray continuum is rapidly variable on time-scales of tens of ks. Fractional variability amplitude increases with energy across the synchrotron hump, consistent with previous studies; we interpret this observation in the context of a model with multiple cells whose emission spectra contain cutoffs that follow a power-law distribution. We also performed time-averaged and time-resolved (time-scales of 6 ks) spectral fits; a broken power-law model fits all spectra well; time-resolved spectral fitting reveals the usual hardening when brightening behaviour. Intra-X-ray cross correlations yield evidence for the 0.6-0.8 keV band to likely lead the other bands by an average of 4.6 +- 2.6 ks, but only during the first half of the observation. The source displayed minimal night-to-night variability at all wavebands thus precluding significant interband correlations during our campaign. The broadband SED is modeled well with a standard one-zone leptonic model, yielding jet parameters consistent with those obtained from previous SEDs of this source., Comment: This article has been accepted for publication in The Monthly Notices of the Royal Astronomical Society (2022), and is published in Volume 513, Issue 2, pp.1662-1679. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. 19 pages; 12 figures
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- 2022
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12. X-ray intraday variability of the TeV blazar Mrk 421 with {\it XMM-Newton}
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Noel, A Priyana, Gaur, Haritma, Gupta, Alok C., Wierzcholska, Alicja, Ostrowski, Michal, Dhiman, Vinit, and Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Highly variable Markarian 421 is a bright high synchrotron energy peaked blazar showing wide featureless non-thermal spectrum making it a good candidate for our study of intraday flux and spectral variations over time. We analyse its X-ray observations of over 17 years taken with the EPIC-PN instrument to probe into the intraday variability properties. The photon energy band of 0.3 - 10.0 keV, and its sub-bands, soft 0.3-2.0 keV and hard 2.0-10.0 keV. To examine flux variability, fractional variability amplitude and the minimum variability timescale have been calculated. We also probed into the spectral variability by studying hardness ratio for each observation and the correlation between the two energy bands using discrete correlation function and inspecting the normalized light curves. The parameters obtained from these methods have been studied for any correlation or non-random trends. From this work, we speculate on the constraints for possible particle acceleration and emission processes in the jet, for better understanding of the processes involving a turbulent behaviour except of shocks. A positive discrete correlation function between the two sub-bands indicates the role of the same electron population in the emission of photons in the two bands. The correlation between the parameters of flux variability and parameters of spectral variation and lags in sub-energy bands provide the constraints to be considered for any modelling of emission processes., Comment: Accepted in APJS on 31 May 2022; Online supplementary material of paper placed in ancillary material on arxiv
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- 2022
13. Study of optical and gamma-ray long-term variability in blazars
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Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Blazars, a subset of powerful active galactic nuclei, feature relativistic jets that shine in a broadband electromagnetic radiation, e. g. from radio to TeV emission. Here I present the results of the studies that explore gamma-ray and optical variability properties of a sample of gamma-ray bright sources Several methods of time-series analyses are performed on the decade-long optical and Fermi/LAT observations. The main results are as follows: The sources are found highly variable in both the bands, and the gamma-ray power spectral density is found to be consistent with flicker noise suggesting long-memory processes at work. While comparing two emission, not only the overall optical and the $\gamma$-ray emission are highly correlated but also both the observation distributions exhibit heavy tailed log-normal distribution and linear RMS-flux relation. In addition, in some of the sources indications of quasi-periodic oscillation were revealed with similar characteristic timescales in both the bands. We discuss the results in light of current blazar models with relativistic shocks propagating down the jet viewed close to the line of sight., Comment: 8 pages, submitted to Acta Physica Polonica B
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- 2022
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14. X-ray timing and spectral variability properties of blazars S5 0716+714, OJ 287, Mrk 501, and RBS 2070
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Mohorian, Maksym, Bhatta, Gopal, Adhikari, Tek P., Dhital, Niraj, Pánis, Radim, Dinesh, Adithiya, Chaudhary, Suvas C., Bachchan, Rajesh K., and Stuchlík, Zdeňek
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The X-ray emission from blazars has been widely investigated using several space telescopes. In this work, we explored statistical properties of the X-ray variability in the blazars S5 0716+714, OJ 287, Mkn 501 and RBS 2070 using the archival observations from the XMM-Newton telescope between the period 2002-2020. Several methods of timing and spectral analyses including fractional variability, minimum variability timescale, power spectral density analyses and countrate distribution were performed. In addition, we fitted various spectral models to the observations as well as estimated hardness ratio. The results show that the sources are moderately variable within the intra-day timescale. Three of the four sources exhibited a clear bi-modal pattern in their countrate distribution revealing possible indication of two distinct countrate states, that is, hard and soft countrate states. The slope indices of the power spectral density were found to be centered around 0.5. Furthermore, the spectra of the sources were fitted with single power-law, broken power-law, log-parabolic and black-body+log-parabolic models (the latter only for OJ 287). We conclude that for most of the observations log-parabolic model was the best fit. The power spectral density analysis revealed the variable nature of PSD slopes in the source light curves. The results of this analysis could indicate the non-stationary nature of the blazar processes on intra-day timescales. The observed features can be explained within the context of current blazar models, in which the non-thermal emission mostly arises from kilo-parsec scale relativistic jets., Comment: 23 pages, 12 figures, accepted to MNRAS
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- 2021
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15. Characterizing Long-term Optical Variability Properties of $\gamma$-ray Bright Blazars
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Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Optical observations of a sample of 12 $\gamma$-ray bright blazars from four optical data archives, AAVSO, SMARTS, Catalina, and Steward Observatory, are compiled to create densely sampled light curves spanning more than a decade. As a part of the blazar multi-wavelength studies, several methods of analyses, e. g., flux distribution and RMS-flux relation, are performed on the observations with an aim to compare the results with the similar ones in the \gama-ray band presented in Bhatta & Dhital 2020. It is found that, similar to $\gamma$-ray band, blazars display significant variability in the optical band that can be characterized with log-normal flux distribution and a power-law dependence of RMS on flux. It could be an indication of possible inherent linear RMS-flux relation, yet the scatter in the data does not allow to rule out other possibilities. When comparing variability properties in the two bands, the blazars in the \gama-rays are found to exhibit stronger variability with steeper possible linear RMS-flux relation and the flux distribution that is more skewed towards higher fluxes. The cross-correlation study shows that except for the source 3C 273, the overall optical and the $\gamma$-ray emission in the sources are highly correlated, suggesting a co-spatial existence of the particles responsible for both the optical and $\gamma$-ray emission. Moreover, the sources S5 0716+714, Mrk 421, Mrk 501, PKS 1424-418 and PKS 2155-304 revealed possible evidence for quasi-periodic oscillations in the optical emission with the characteristic timescales, which are comparable to those in the $\gamma$-ray band detected in our previous work., Comment: 25 pages, 7 Figures, ApJ accepted
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- 2021
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16. Exploring the variability properties of gamma-ray emission from blazars
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Bhatta, Gopal and Dhital, Niraj
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present results of variability study of a sample of 20 powerful blazars using Fermi/LAT (0.1--300 GeV) observations. We studied decade-long observations applying various analysis tools such as flux distribution, symmetry analysis, and RMS-flux relation. It was found that the $\gamma$-ray flux distribution closely resembles a log-normal probability distribution function and can be characterized by linear RMS-flux relation. The power spectral density analysis shows the statistical variability properties of the sources as studied are consistent with flicker noise, an indication of long-memory processes at work. Statistical analysis of the distribution of flux rise and decay rates in the light curves of the sources, aimed at distinguishing between particle acceleration and energy-dissipation timescales, counter-intuitively suggests that both kinds of rates follow a similar distribution and the derived mean variability timescales are on the order of a few weeks. The corresponding emission region size is used to constrain the location of $\gamma$-ray production sites in the sources to be a few parsecs. Additionally, using Lomb-Scargle periodogram and weighted wavelet z-transform methods and extensive Monte Carlo simulations, we detected year-timescale quasi-periodic oscillations in the sources S5 0716+714, Mrk 421, ON +325, PKS 1424-418, and PKS 2155-304. We also performed recurrence quantification analysis of the sources and directly measure the deterministic quantities, which suggest that the dynamical processes in blazars could be a combination of deterministic and stochastic processes, while some of the source light curves revealed significant deterministic content., Comment: 8 pages, 37th International Cosmic Ray Conference (ICRC 2021), The Astroparticle Physics Conference Proceeding
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- 2021
17. Deterministic Aspect of the $\gamma$-ray Variability in Blazars
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Bhatta, Gopal, Pánis, Radim, and Stuchlík, Zdeněk
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Linear time series analysis, mainly the Fourier transform based methods, has been quite successful in extracting information contained in the ever-modulating light curves (Lcs) of active galactic nuclei, and thereby contribute in characterizing the general features of supermassive black hole systems. In particular, the statistical properties of $\gamma$-ray variability of blazars are found to be fairly represented by flicker noise in the temporal frequency domain. However, these conventional methods have not been able to fully encapsulate the richness and the complexity displayed in the light curves of the sources. In this work, to complement our previous study on the similar topic, we perform non-linear time series analysis of the decade-long Fermi/LAT observations of 20 $\gamma$-ray bright blazars. The study is motivated to address one of the most relevant queries that whether the dominant dynamical processes leading to the observed $\gamma$-ray variability are of deterministic or stochastic nature. For the purpose, we perform Recurrence Quantification Analysis of the blazars and directly measure the quantities which suggest that the dynamical processes in blazar could be a combination of deterministic and stochastic processes, while some of the source light curves revealed significant deterministic content. The result with possible implication of strong disk-jet connection in blazars could prove to be significantly useful in constructing models that can explain the rich and complex multi-wavelength observational features in active galactic nuclei. In addition, we estimate the dynamical timescales, so called "trapping timescales", in the order of a few weeks., Comment: ApJ accepted, 20 pages and 6 figures
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- 2020
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18. Cosmic Ray Extremely Distributed Observatory
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Homola, Piotr, Beznosko, Dmitriy, Bhatta, Gopal, Bibrzycki, Lukasz, Borczynska, Michalina, Bratek, Lukasz, Budnev, Nikolai, Burakowski, Dariusz, Alvarez-Castillo, David E., Cheminant, Kevin Almeida, Cwikla, Aleksander, Dam-o, Punsiri, Dhital, Niraj, Duffy, Alan R., Glownia, Piotr, Gorzkiewicz, Krzysztof, Gora, Dariusz, Gupta, Alok C., Hlavkova, Zuzana, Homola, Martin, Jalocha, Joanna, Kaminski, Robert, Karbowiak, Michal, Kasztelan, Marcin, Kierepko, Renata, Knap, Marek, Kovacs, Peter, Kulinski, Szymon, Lozowski, Bartosz, Magrys, Marek, Medvedev, Mikhail V., Medrala, Justyna, Mietelski, Jerzy W., Miszczyk, Justyna, Mozgova, Alona, Napolitano, Antonio, Nazari, Vahab, Ng, Y. Jack, Niedzwiecki, Michal, Oancea, Cristina, Ogan, Boguslaw, Opila, Gabriela, Oziomek, Krzysztof, Pawlik, Maciej, Piekarczyk, Marcin, Poncyliusz, Bozena, Pryga, Jerzy, Rosas, Matias, Rzecki, Krzysztof, Zamora-Saa, Jilberto, Smelcerz, Katarzyna, Smolek, Karel, Stanek, Weronika, Stasielak, Jaroslaw, Stuglik, Slawomir, Sulma, Jolanta, Sushchov, Oleksandr, Svanidze, Manana, Tam, Kyle, Tursunov, Arman, Vaquero, Jose M., Wibig, Tadeusz, and Wozniak, Krzysztof W.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The Cosmic Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic ray ensembles (CRE): groups of a minimum of two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and preparing to observe unexpected physics, it is also suitable for multi-messenger and multi-mission applications. Perfectly matched to CREDO capabilities, CRE could be formed both within classical models (e.g. as products of photon-photon interactions), and exotic scenarios (e.g. as results of decay of Super Heavy Dark Matter particles). Their fronts might be significantly extended in space and time, and they might include cosmic rays of energies spanning the whole cosmic ray energy spectrum, with a footprint composed of at least two extensive air showers with correlated arrival directions and arrival times. Since CRE are mostly expected to be spread over large areas and, because of the expected wide energy range of the contributing particles, CRE detection might only be feasible when using available cosmic ray infrastructure collectively, i.e. as a globally extended network of detectors. Thus, with this review article, the CREDO Collaboration invites the astroparticle physics community to actively join or to contribute to the research dedicated to CRE, and in particular to share any cosmic ray data useful for the specific CRE detection strategies., Comment: 59 pages, 23 figures
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- 2020
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19. Gamma-ray Blazar variability: New statistical methods of time-flux distributions
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Duda, Jaroslaw and Bhatta, Gopal
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Variable \gama-ray emission from blazars, one of the most powerful classes of astronomical sources featuring relativistic jets, is a widely discussed topic. In this work, we present the results of a variability study of a sample of 20 blazars using \gama-ray (0.1--300~GeV) observations from Fermi/LAT telescope. Using maximum likelihood estimation (MLE) methods, we find that the probability density functions that best describe the $\gamma$-ray blazar flux distributions use the stable distribution family, which generalizes the Gaussian distribution. The results suggest that the average behavior of the \gama-ray flux variability over this period can be characterized by log-stable distributions. For most of the sample sources, this estimate leads to standard log-normal distribution ($\alpha=2$). However, a few sources clearly display heavy tail distributions (MLE leads to $\alpha<2$), suggesting underlying multiplicative processes of infinite variance. Furthermore, the light curves were analyzed by employing novel non-stationarity and autocorrelation analyses. The former analysis allowed us to quantitatively evaluate non-stationarity in each source -- finding the forgetting rate (corresponding to decay time) maximizing the log-likelihood for the modeled evolution of the probability density functions. Additionally, evaluation of local variability allows us to detect local anomalies, suggesting a transient nature of some of the statistical properties of the light curves. With the autocorrelation analysis, we examined the lag dependence of the statistical behavior of all the $\{(y_t,y_{t+l})\}$ points, described by various mixed moments, allowing us to quantitatively evaluate multiple characteristic time scales and implying possible hidden periodic processes., Comment: 13 pages, 9 Figures, MNRAS accepted
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- 2020
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20. The Nature of $\gamma$-ray Variability in Blazars
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Bhatta, Gopal and Dhital, Niraj
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present an in-depth and systematic variability study of a sample of 20 powerful blazars, including 12 BL Lacs and 8 flat spectrum radio quasars, applying various analysis tools such as flux distribution, symmetry analysis, and time series analysis on the decade-long Fermi/LAT observations. The results show that blazars with steeper \gama-ray spectral indexes are found to be more variable; and the \gama-ray flux distribution closely resembles lognormal probability distribution function. The statistical variability properties of the sources as studied by power spectral density analysis are consistent with \emph{flicker noise} ($P(\nu)\propto1/\nu$) -- an indication of long-memory processes at work. Statistical analysis of the distribution of flux rise and decay rates in the light curves of the sources, aimed at distinguishing between particle acceleration and energy dissipation timescales, counter-intuitively suggests that both kinds of rates follow a similar distribution and the derived mean variability timescales are in the order of a few weeks. The corresponding emission region size is used to constrain location of \gama-ray production sites in the sources to be a few parsecs. Additionally, using Lomb-Scargle periodogram and weighted wavelet z-transform methods and extensive Monte Carlo simulations, we detected year timescale quasi-periodic oscillations in the sources S5 0716+714, Mrk 421, ON +325, PKS 1424-418 and PKS 2155-304. The detection significance was computed taking proper account of the red-noise and other artifacts inherent in the observations. We explain the results in the light of current blazar models with relativistic shocks propagating down the jet viewed close to the line of sight., Comment: ApJ accepted 32 pages, 12 figures
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- 2019
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21. Study of periodic signals from blazars
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Bhatta, Gopal
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
The search for periodic signals from blazars has become an actively pursued field of research in recent years. This is because periodic signals bring us information about the processes occurring near the innermost regions of blazars, which are mostly inaccessible to our direct view. Such signals provide insights into some of the extreme conditions that take place in the vicinity of supermassive black holes that lead to the launch of the relativistic jets. In addition, studies of characteristic timescales in blazar light curves shed light on some of the challenging issues in blazar physics that includes disk-jet connection, strong gravity near fast rotating supermassive black holes and release of gravitational waves from binary supermassive black hole systems. However, a number of issues associated with the search quasi-periodic oscillations (QPOs) in blazar e.g., red-noise dominance, modest significance of the detection, periodic modulation lasting for only a couple of cycles and their transient nature, make it difficult to estimate the true significance of the detection. Consequently, it also becomes difficult to make meaningful inferences about the nature of the on-going processes. In this proceedings, results of study focused on searching QPOs in a number of blazar multi-frequency light curves are summarized. The time series analyses of long term observations of the blazars revealed presence of year-timescale QPOs in the sources including OJ 287 (optical), Mrk 501 (gamma-ray), J1043+2408 (radio) and PKS 0219-164 (radio). As likely explanations, we discuss a number of scenarios including binary supermassive black hole systems, Lense-Thirring precession, and jet precession., Comment: Published in Universe Proceedings, https://doi.org/10.3390/proceedings2019017015
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- 2019
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22. Statistical analysis of micro-variability properties of the blazar S5 0716+714
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Xu, Jingran, Hu, Shaoming, Webb, James R., Bhatta, Gopal, Jiang, Yunguo, Chen, Xu, Alexeeva, Sofya, and Li, Yutong
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
The typical blazar S5 0716$+$714 is very interesting due to its rapid and large amplitude variability and high duty cycle of micro-variability in optical band. We analyze the observations in I, R and V bands obtained with the $1.0m$ telescope at Weihai observatory of Shandong University from 2011 to 2018. The model of synchrotron radiation from turbulent cells in a jet has been proposed as a mechanism for explaining micro-variability seen in blazar light curves. Parameters such as the sizes of turbulent cells, the enhanced particle densities, and the location of the turbulent cells in the jet can be studied using this model. The model predicts a time lag between variations as observed in different frequency bands. Automatic model fitting method for micro-variability is developed, and the fitting results of our multi-frequency micro-variability observations support the model. The results show that both the amplitude and duration of flares decomposed from the micro-variability light curves confirm to the log-normal distribution. The turbulent cell size is within the range of about 5 to 55 AU, and the time lags of the micro-variability flares between the I-R and R-V bands should be several minutes. The time lags obtained from the turbulence model are consistent with the fitting statistical results, and the time lags of flares are correlated with the time lags of the whole light curve., Comment: 12 pages, 11 figures, Accepted by ApJ
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- 2019
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23. Detection of periodic radio signal from the blazar J1043+2408
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Bhatta, Gopal
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
Search for periodic signals from blazars has become widely discussed topic in recent years. In the scenario that such periodic changes originate from the innermost regions of blazars, the signals bear imprints of the processes occurring near the central engine, which is mostly inaccessible to our direct view. Such signals provide insights into various aspect of blazar studies including disk-jet connection, magnetic field configuration and, more importantly, strong gravity near the supermassive black holes and release of gravitational waves from the binary supermassive black hole systems. In this work, we report detection of a periodic signal in the radio light curve of the blazar J1043+2408 spanning $\sim$10.5 years. We performed multiple methods of time series analysis, namely, epoch folding, Lomb-Scargle periodogram, and discrete auto-correlation function. All three methods consistently reveal a repeating signal with a periodicity of $\sim560$ days. To robustly account for the red-noise processes usually dominant in the blazar variability and other possible artifacts, a large number of Monte Carlo simulations were performed. This allowed us to estimate a high significance (99.9\% local and 99.4\% global) against possible spurious detection. As possible explanations, we discuss a number of scenarios including binary supermassive black hole system, Lense-Thirring precession and jet precession., Comment: 10 pages, 4 figures, Galaxies accepted
- Published
- 2018
24. Multiwavelength intraday variability: what do the studies tell us about blazar jets?
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Bhatta, Gopal
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
In this presentation, we report the results of intraday variability in the optical (BVRI bands) and hard X-ray band (3-79 keV) in a number of blazars. In the optical microvariability studies of the blazars S5 0716+714 and BL Lac, we observed many interesting features such as rapid variability, large variability amplitude, presence of characteristic timescales, bluer-when-brighter achromatic behavior, and single power-law power spectral density. In {\it NuSTAR} observations of several blazars, using spectral and timing analysis, we found similar features consistent with the optical studies. In addition, in BL Lacs we estimated the Lorentz factor of the population of highest energy electrons emitting synchrotron emission, and whereas in flat-spectrum radio quasars, using external Compton models, we estimated the energy of the lower end of the injected electrons to be a few tens of Lorentz factors. In addition, we find that the low flux state exhibit more rapid variability in contrast to the previously reported results showing high flux states displaying rapid variability. In both the studies, the size of the emission regions estimated using variability timescales turn out to be an order magnitude smaller than the gravitational radius of a typical black-hole masses between $\sim 10^8-10^9$ solar masses, believed to be at the center of the radio-loud AGN. The results of the studies suggest that these low-amplitude rapid variability might originate as a result of magnetohydrodynamical instabilities near the base of the jets triggered by the processes modulated by the magnetic field at accretion disc., Comment: Proceedings IAU General Assembly, Vienna 2018; Focus Meeting, Radio Galaxies: Resolving the AGN phenomenon
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- 2018
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25. Predicting conditional probability distributions of redshifts of Active Galactic Nuclei using Hierarchical Correlation Reconstruction
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Duda, Jaroslaw, primary and Bhatta, Gopal, additional
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- 2024
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26. Blazar Mrk 501 shows rhythmic oscillations in its $\gamma$-ray emission
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Bhatta, Gopal
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
Quasi-periodic oscillations (QPO) originating from innermost regions of blazars can provide unique perspective of some of the burning issues in blazar studies including disk-jet connection, launch of relativistic jets from the central engine, and other extreme conditions near the fast rotating supermassive black holes. However, a number of hurdles associated with searching QPOs in blazars e.g., red-noise dominance, modest significance of the detection and periodic modulation lasting for only a couple of cycles, make it difficult to estimate the true significance of the detection. In this work, we report a $\sim$ 330-day QPO in the Fermi/LAT observations of the blazar Mrk 501 spanning nearly a decade. To establish consistency of the result, we adopted multiple approaches to the time series analysis and employed four widely known methods. Among these, Lomb-Scargle periodogram and weighted wavelet z-transform represent frequency domain based methods whereas epoch folding and z-transformed discrete auto-correlation function are time-domain based analysis. Power spectrum response method was followed to properly account for the red-noise, largely inherent in blazar light curves. Both local and global significance of the signal were found to be above 99\% over possible spurious detection. In the context where not many $\gamma$-ray QPOs have been reported to last more than 5 cycles, this might be one of the few instances where we witness a sub-year timescale $\gamma$-ray QPO persisting nearly 7 cycles. A number of possible scenarios linked with binary supermassive black hole, relativistic jets, and accretion disks can be invoked to explain the transient QPO., Comment: 9 pages and 6 figures, MNRAS accepted
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- 2018
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27. Microvariability in BL Lac: Zooming into the Innermost Blazar Regions
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Bhatta, Gopal and Webb, James R.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
In this work, we present the results of our multi-band microvariability study of the famous blazar BL Lac. We performed microvariablity observations of the source in the optical VRI bands for 4 nights in the year 2016. We studied the intranight flux and spectral variability of the source in detail with an objective to characterize microvariability in the blazars, a frequently observed phenomenon in blazars. The results show that the source often displays a fast flux variability with an amplitude as large as ~ 0.2 magnitude within a few hours, and that the color variability in the similar time scales can be characterized as "bluer-when-brighter" trend. We also observed markedly curved optical spectrum during one of the nights. Furthermore, the correlation between multi-band emission shows that in general the emission in all the bands are highly correlated; and in one of the nights V band emission was found to lead the I band emission by ~ 20 minutes. The search for characteristic timescale using auto-correlation function and the structure function analyses reveals characteristic timescale of ~ 48 minutes in one of the R band observations. We try to explain the observed results in the context of the passage of shock waves through the relativistic outflows in blazars., Comment: 13 pages and 7 figures; submitted to Galaxies
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- 2017
28. Hard X-ray properties of NuSTAR blazars
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Bhatta, Gopal, Mohorian, Maksym, and Bilinsky, Illya
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Context. Investigation of the hard X-ray emission properties of blazars is key to the understanding of the central engine of the sources and associated jet process. In particular, simultaneous spectral and timing analyses of the intra-day hard X-ray observations provide us a means to peer into the compact innermost blazar regions, not accessible to our current instruments. Aims. The primary objective of the work is to associate the observed hard X-ray variability properties in the blazars to their flux and spectral states, thereby, based on the correlation among them, extract the details about the emission regions and the processes occurring near the central engine. Methods. We carried out timing, spectral and cross-correlation analysis of 31 NuSTAR observations of 13 blazars. We investigated the spectral shapes of the sources using single power-law, broken power-law and log-parabola models. We also studies the co-relation between the soft and the hard emission using z-transformed discrete correlation function. Results. We found that for most of the sources the hard X-ray emission can be well represented by log-parabola model; and that the spectral slopes for different blazar sub-classes are consistent with so called blazar sequence. We noted a close connection between the flux and spectral slope within the source sub-class in the sense that high flux and/or flux states tend to be harder in spectra. In BL Lacertae objects, assuming particle acceleration by diffusive shocks and synchrotron cooling as the dominant processes governing the observed flux variability, we constrain the magnetic field of the emission region to be a few gauss; whereas in flat-spectrum radio quasars, using external Compton models, we estimate the energy of the lower end of the injected electrons to be a few Lorentz factors., Comment: 12 figures, 21 pages, A&A accepted
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- 2017
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29. Radio and $\gamma$-ray variability in the BL Lac PKS 0219 -164: Detection of quasi-periodic oscillations in the radio light curve
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Bhatta, Gopal
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
In this work, we explore the long-term variability properties of the blazar PKS 0219-164 in the radio and the $\gamma$-ray regime, utilizing the OVRO 15 GHz and the \fermi/LAT observations from the period 2008--2017. We found that $\gamma$-ray emission is more variable than the radio emission implying that $\gamma$ ray emission possibly originated in more compact regions while the radio emission represented continuum emission from the large scale jets. Also, in $\gamma$-ray the source exhibited spectral variability characterized by the \emph{ softer-when-brighter} trend, a less frequently observed feature in the high energy emission by BL Lacs. In radio, using Lomb-Scargle periodogram and weighted wavelet z-transform, we detected a strong signal of quasi-periodic oscillation (QPO) with a periodicity of 270 $\pm$ 26 days with possible harmonics of 550 $\pm$ 42 and 1150 $\pm$ 157 days periods. At a time when the issue of the detection of QPOs in blazars is still under debate, the observed QPO with high statistical significance ( $\sim$ 97\% -- 99\% global significance over underlying red-noise processes) and persistent over nearly 10 oscillations could make one of the strongest cases for the detection of QPOs in blazar light curves. We discuss various blazar models that might lead to the $\gamma$-ray and radio variability, QPO, and the achromatic behavior seen in the high energy emission from the source., Comment: ApJ, in press. 9 pages and 5 figures
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- 2017
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30. Gamma-ray blazar classification using machine learning with advanced weight initialization and self-supervised learning techniques
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Bhatta, Gopal, primary, Gharat, Sarvesh, additional, Borthakur, Abhimanyu, additional, and Kumar, Aman, additional
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- 2024
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31. Discovery of a Highly Polarized Optical Microflare in the Blazar S5 0716+714 During 2014 WEBT Campaign
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Bhatta, Gopal, Goyal, Arti, Ostrowski, Michal, Stawarz, Łukasz, Arkharov, A. A., Akitaya, Hiroshi, Bachev, Rumen, Benítez, Erika, Borman, G. A., Carosati, Daniele, Cason, Andy, Damljanovic, Goran, Dhalla, Sarah, Frasca, Antonio, Hiriart, David, Hu, Shao Ming, Itoh, Ryosuke, Jableka, Damian, Jorstad, Svetlana, Kawabata, Koji, Klimanov, Sergey, Kurtanidze, Omar, Larionov, Valeri, Laurence, Douglas, Leto, Giuseppe, Markowitz, Alex, Marscher, Alan P., Moody, J., Moritani, Yuki, Ohlert, Johannes, Di Paola, Andrea, Raiteri, Claudia M., Rizzi, Nicola, Sadun, Alberto, Sasada, Mahito, Sergeev, Sergey G, Strigachev, Anton, Takaki, Katsutoshi, Troitsky, Ivan, Ui, Takahiro, Villata, Massimo, Vince, Oliver, Webb, James, Yoshida, Michitoshi, and Zola, Staszek
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
The occurrence of low-amplitude flux variations in blazars on hourly timescales, commonly known as microvariability, is still a widely debated subject in high-energy astrophysics. Several competing scenarios have been proposed to explain such occurrences, including various jet plasma instabilities leading to the formation of shocks, magnetic reconnection sites, and turbulence. In this letter we present the results of our detailed investigation of a prominent, five-hour-long optical microflare detected during recent WEBT campaign in 2014, March 2-6 targeting the blazar 0716+714. After separating the flaring component from the underlying base emission continuum of the blazar, we find that the microflare is highly polarized, with the polarization degree $\sim (40-60)\%$$\pm (2-10)\%$, and the electric vector position angle $\sim (10 - 20)$deg$\pm (1-8)$deg slightly misaligned with respect to the position angle of the radio jet. The microflare evolution in the $(Q,\,U)$ Stokes parameter space exhibits a looping behavior with a counter-clockwise rotation, meaning polarization degree decreasing with the flux (but higher in the flux decaying phase), and approximately stable polarization angle. The overall very high polarization degree of the flare, its symmetric flux rise and decay profiles, and also its structured evolution in the $Q-U$ plane, all imply that the observed flux variation corresponds to a single emission region characterized by a highly ordered magnetic field. As discussed in the paper, a small-scale but strong shock propagating within the outflow, and compressing a disordered magnetic field component, provides a natural, though not unique, interpretation of our findings., Comment: 9 pages, 4 Figures, ApJ Letter accepted
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- 2015
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32. Estimation of redshift and associated uncertainty of Fermi/LAT extra-galactic sources with Deep Learning
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Gharat, Sarvesh, primary, Borthakur, Abhimanyu, additional, and Bhatta, Gopal, additional
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- 2023
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33. Estimation of redshift and associated uncertainty of Fermi/LAT extragalactic sources with Deep Learning.
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Gharat, Sarvesh, Borthakur, Abhimanyu, and Bhatta, Gopal
- Subjects
DEEP learning ,ACTIVE galactic nuclei ,SUPERMASSIVE black holes ,STATISTICAL correlation ,REDSHIFT ,STANDARD deviations ,ACTIVE galaxies - Abstract
With the advancement of technology, machine learning-based analytical methods have pervaded nearly every discipline in modern studies. Particularly, a number of methods have been employed to estimate the redshift of gamma-ray loud active galactic nuclei (AGN), which are a class of supermassive black hole systems known for their intense multi-wavelength emissions and violent variability. Determining the redshifts of AGNs is essential for understanding their distances, which, in turn, sheds light on our current understanding of the structure of the nearby universe. However, the task involves a number of challenges, such as the need for meticulous follow-up observations across multiple wavelengths and astronomical facilities. In this study, we employ a simple yet effective deep learning model with a single hidden layer having 64 neurons and a dropout of 0.25 in the hidden layer on a sample of AGNs with known redshifts from the latest AGN catalogue, 4LAC-DR3, obtained from Fermi-LAT. We utilized their spectral, spatial, and temporal properties to robustly predict the redshifts of AGNs as well quantify their associated uncertainties by modifying the model using two different variational inference methods. We achieve a correlation coefficient of 0.784 on the test set from the frequentist model and 0.777 and 0.778 from both the variants of variational inference, and, when used to make predictions on the samples with unknown redshifts, we achieve mean predictions of 0.421, 0.415, and 0.393, with standard deviations of 0.258, 0.246, and 0.207 from the models, respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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34. Constraining X-Ray Variability of the Blazar 3C 273 Using XMM-Newton Observations over Two Decades
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Dinesh, Adithiya, primary, Bhatta, Gopal, additional, Adhikari, Tek P., additional, Mohorian, Maksym, additional, Dhital, Niraj, additional, Chaudhary, Suvas C., additional, Pánis, Radim, additional, and Góra, Dariusz, additional
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- 2023
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35. A Stochastic Approach to Reconstruct Gamma-Ray-burst Light Curves
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Dainotti, Maria G., primary, Sharma, Ritwik, additional, Narendra, Aditya, additional, Levine, Delina, additional, Rinaldi, Enrico, additional, Pollo, Agnieszka, additional, and Bhatta, Gopal, additional
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- 2023
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36. Detection of periodicity in the gamma-ray light curve of the BL Lac 4FGL J2202.7+4216
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Banerjee, Anuvab, primary, Sharma, Ajay, additional, Mandal, Avijit, additional, Das, Avik Kumar, additional, Bhatta, Gopal, additional, and Bose, Debanjan, additional
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- 2023
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37. Multiband optical variability of a newly discovered 12 blazars sample from 2013 – 2019
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Jovanović, Miljana D, primary, Damljanović, Goran, additional, Taris, François, additional, Gupta, Alok C, additional, and Bhatta, Gopal, additional
- Published
- 2023
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38. Catching profound optical flares in blazars
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Bhatta, Gopal, primary, Zola, Staszek, additional, Drozdz, M, additional, Reichart, Daniel, additional, Haislip, Joshua, additional, Kouprianov, Vladimir, additional, Matsumoto, Katsura, additional, Sonbas, Eda, additional, Caton, D, additional, Pajdosz-Śmierciak, Urszula, additional, Simon, A, additional, Provencal, J, additional, Góra, Dariusz, additional, and Stachowski, Grzegorz, additional
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- 2023
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39. Climatic and non-climatic factors influencing changing agricultural practices across different rainfall regimes in South Asia
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Bhatta, Gopal Datt, Aggarwal, Pramod Kumar, Kristjanson, Patti, and Shrivastava, Amit Kumar
- Published
- 2016
40. Exploring short-term optical variability of blazars using TESS
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Pininti, Vivek Reddy, primary, Bhatta, Gopal, additional, Paul, Sagarika, additional, Kumar, Aman, additional, Rajgor, Aayushi, additional, Barnwal, Rahul, additional, and Gharat, Sarvesh, additional
- Published
- 2022
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41. Blazar Jets as Possible Sources of Ultra-High Energy Photons: A Short Review
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Bhatta, Gopal, primary
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- 2022
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42. Agricultural innovation and adaptation to climate change: empirical evidence from diverse agro-ecologies in South Asia
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Bhatta, Gopal Datt, Ojha, Hemant Raj, Aggarwal, Pramod Kumar, Sulaiman, V. Rasheed, Sultana, Parvin, Thapa, Dhanej, Mittal, Nimisha, Dahal, Khemraj, Thomson, Paul, and Ghimire, Laxman
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- 2017
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43. Is rainfall gradient a factor of livelihood diversification? Empirical evidence from around climatic hotspots in Indo-Gangetic Plains
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Bhatta, Gopal Datt, Aggarwal, Pramod Kumar, Shrivastava, Amit Kumar, and Sproule, Lindsay
- Published
- 2016
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44. Adoption of Improved Rice Varieties in Nepal: Impact on Household Wellbeing
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Budhathoki, Nandakaji and Bhatta, Gopal D.
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- 2016
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45. X-Ray Intraday Variability of the TeV Blazar Markarian 421 with XMM-Newton
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Noel, A Priyana, primary, Gaur, Haritma, additional, Gupta, Alok C., additional, Wierzcholska, Alicja, additional, Ostrowski, Michał, additional, Dhiman, Vinit, additional, and Bhatta, Gopal, additional
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- 2022
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46. Rapid X-ray variability in Mkn 421 during a multiwavelength campaign
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Markowitz, Alex G, primary, Nalewajko, Krzysztof, additional, Bhatta, Gopal, additional, Dewangan, Gulab C, additional, Chandra, Sunil, additional, Dorner, Daniela, additional, Schleicher, Bernd, additional, Pajdosz-Śmierciak, Urszula, additional, Stawarz, Łukasz, additional, Zola, Staszek, additional, Ostrowski, Michał, additional, Carosati, Daniele, additional, Krishnan, Saikruba, additional, Bachev, Rumen, additional, Benítez, Erika, additional, Gazeas, Kosmas, additional, Hiriart, David, additional, Hu, Shao-Ming, additional, Larionov, Valeri, additional, Marchini, Alessandro, additional, Matsumoto, Katsura, additional, Nikiforova, A A, additional, Pursimo, Tapio, additional, Raiteri, Claudia M, additional, Reichart, Daniel E, additional, Rodriguez, Diego, additional, Semkov, Evgeni, additional, Strigachev, Anton, additional, Sugiura, Yuki, additional, Villata, Massimo, additional, Webb, James R, additional, Arbet-Engels, Axel, additional, Baack, Dominik, additional, Balbo, Matteo, additional, Biland, Adrian, additional, Bretz, Thomas, additional, Buss, Jens, additional, Eisenberger, Laura, additional, Elsaesser, Dominik, additional, Hildebrand, Dorothee, additional, Iotov, Roman, additional, Kalenski, Adelina, additional, Mannheim, Karl, additional, Mitchell, Alison, additional, Neise, Dominik, additional, Noethe, Maximilian, additional, Paravac, Aleksander, additional, Rhode, Wolfgang, additional, Sliusar, Vitalii, additional, and Walter, Roland, additional
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- 2022
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47. Arrival Directions of Cosmic Rays above 32 EeV from Phase One of the Pierre Auger Observatory
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Abreu, Pedro, Aglietta, Marco, Albury, Justin M., Allekotte, Ingomar, Almeida Cheminant, Kevin, Almela, Alejandro, Alvarez-Muñiz, Jaime, Alves Batista, Rafael, Ammerman Yebra, Juan, Anastasi, Gioacchino Alex, Anchordoqui, Luis, Andrada, Belén, Andringa, Sofia, Aramo, Carla, Araújo Ferreira, Paulo Ricardo, Arnone, Enrico, Arteaga Velázquez, Juan Carlos, Asorey, Hernán Gonzalo, Assis, Pedro, Avila, Gualberto, Avocone, Emanuele, Badescu, Alina Mihaela, Bakalova, Alena, Balaceanu, Alexandru, Barbato, Felicia, Bellido, Jose A., Berat, Corinne, Bertaina, Mario Edoardo, Bhatta, Gopal, Biermann, Peter, Binet, Virginia, Bismark, Kathrin, Bister, Teresa Karolin, Biteau, Jonathan, Blazek, Jiri, Bleve, Carla, Blümer, Johannes, Boháčová, Martina, Boncioli, Denise, Bonifazi, Carla, Bonneau Arbeletche, Luan, Borodai, Nataliia, Botti, Ana Martina, Brack, Jeffrey, Bretz, Thomas, Brichetto Orchera, P. Gabriel, Briechle, Florian Lukas, Buchholz, Peter, Bueno, Antonio, Buitink, Stijn, Buscemi, Mario, Büsken, Max, Caballero-Mora, Karen S., Caccianiga, Lorenzo, Canfora, Fabrizia, Caracas, Ioana, Caruso, Rossella, Castellina, Antonella, Catalani, Fernando, Cataldi, Gabriella, Cazon, Lorenzo, Cerda, Marcos, Chinellato, Jose Augusto, Chudoba, Jiri, Chytka, Ladislav, Clay, Roger W., Cobos Cerutti, Agustín, Colalillo, Roberta, Coleman, Alan, Coluccia, Maria Rita, Conceição, Ruben, Condorelli, Antonio, Consolati, Giovanni, Contreras, Fernando, Convenga, Fabio, Correia dos Santos, Diego, Covault, Corbin, Dasso, Sergio, Daumiller, Kai, Dawson, Bruce R., Day, Jarryd A., de Almeida, Rogerio M., de Jesús, Joaquín, de Jong, Sijbrand J., de Mello Neto, J. R. T., De Mitri, Ivan, de Oliveira, Jaime, de Oliveira Franco, Danelise, de Palma, Francesco, de Souza, Vitor, De Vito, Emanuele, Del Popolo, Antonino, del Río, Mariano, Deligny, Olivier, Deval, Luca, di Matteo, Armando, Dobre, Madalina, Dobrigkeit, Carola, D'Olivo, Juan Carlos, Domingues Mendes, Luis Miguel, dos Anjos, Rita, Dova, Maria Teresa, Ebr, Jan, Engel, Ralph, Epicoco, Italo, Erdmann, Martin, Escobar, Carlos O., Etchegoyen, Alberto, Falcke, Heino, Farmer, John, Farrar, Glennys, Fauth, Anderson, Fazzini, Norberto, Feldbusch, Fridtjof, Fenu, Francesco, Fick, Brian, Figueira, Juan Manuel, Filipčič, Andrej, Fitoussi, Thomas, Fodran, Tomas, Fujii, Toshihiro, Fuster, Alan, Galea, Cristina, Galelli, Claudio, García, Beatriz, Gemmeke, Hartmut, Gesualdi, Flavia, Gherghel-Lascu, Alexandru, Ghia, Piera Luisa, Giaccari, Ugo, Giammarchi, Marco, Glombitza, Jonas, Gobbi, Fabian, Gollan, Fernando, Golup, Geraldina, Gómez Berisso, Mariano, Gómez Vitale, Primo F., Gongora, Juan Pablo, González, Juan Manuel, González, Nicolás, Goos, Isabel, Góra, Dariusz, Gorgi, Alessio, Gottowik, Marvin, Grubb, Trent D., Guarino, Fausto, Guedes, Germano, Guido, Eleonora, Hahn, Steffen, Hamal, Petr, Hampel, Matías Rolf, Hansen, Patricia, Harari, Diego, Harvey, Violet M., Haungs, Andreas, Hebbeker, Thomas, Heck, Dieter, Hill, Gary C., Hojvat, Carlos, Hörandel, Jörg, Horvath, Pavel, Hrabovský, Miroslav, Huege, Tim, Insolia, Antonio, Isar, Paula Gina, Janecek, Petr, Johnsen, Jeffrey A., Jurysek, Jakub, Kääpä, Alex, Kampert, Karl-Heinz, Keilhauer, Bianca, Khakurdikar, Abha, Kizakke Covilakam, Varada Varma, Klages, Hans, Kleifges, Matthias, Kleinfeller, Jonny, Knapp, Felix, Kunka, Norbert, Lago, Bruno L., Langner, Niklas Uwe, Leigui de Oliveira, Marcelo Augusto, Lenok, Vladimir, Letessier-Selvon, Antoine, Lhenry-Yvon, Isabelle, Lo Presti, Domenico, Lopes, Luis, López, Rebeca, Lu, Lu, Luce, Quentin, Lundquist, Jon Paul, Machado Payeras, Allan, Mancarella, Giovanni, Mandat, Dusan, Manning, Bradley C., Manshanden, Julien, Mantsch, Paul, Marafico, Sullivan, Mariani, Federico Maria, Mariazzi, Analisa, Mariş, Ioana, Marsella, Giovanni, Martello, Daniele, Martinelli, Sara, Martínez Bravo, Oscar, Mastrodicasa, Massimo, Mathes, Hermann-Josef, Matthews, James, Matthiae, Giorgio, Mayotte, Eric, Mayotte, Sonja, Mazur, Peter, Medina-Tanco, Gustavo, Melo, Diego, Menshikov, Alexander, Michal, Stanislav, Micheletti, Maria Isabel, Miramonti, Lino, Mollerach, Silvia, Montanet, François, Morejon, Leonel, Morello, Carlo, Mostafá, Miguel, Müller, Ana L., Muller, Marcio Aparecido, Mulrey, Katharine, Mussa, Roberto, Muzio, Marco, Namasaka, Wilson M., Nasr-Esfahani, Alina, Nellen, Lukas, Nicora, Gabriela, Niculescu-Oglinzanu, Mihai, Niechciol, Marcus, Nitz, Dave, Norwood, Ian, Nosek, Dalibor, Novotny, Vladimir, Nožka, Libor, Nucita, Achille, Núñez, Luis, Oliveira, Cainã, Palatka, Miroslav, Pallotta, Juan, Papenbreer, Philipp, Parente, Gonzalo, Parra, Alejandra, Pawlowsky, Jannis, Pech, Miroslav, Pękala, Jan, Pelayo, Rodrigo, Peña-Rodriguez, Jesús, Pereira Martins, Edyvania Emily, Perez Armand, Johnnier, Pérez Bertolli, Carmina, Perrone, Lorenzo, Petrera, Sergio, Petrucci, Camilla, Pierog, Tanguy, Pimenta, Mário, Pirronello, Valerio, Platino, Manuel, Pont, Bjarni, Pothast, Mart, Privitera, Paolo, Prouza, Michael, Puyleart, Andrew, Querchfeld, Sven, Rautenberg, Julian, Ravignani, Diego, Reininghaus, Maximilian, Ridky, Jan, Riehn, Felix, Risse, Markus, Rizi, Vincenzo, Rodrigues de Carvalho, Washington, Rodriguez Rojo, Jorge Rubén, Roncoroni, Matías J., Rossoni, Simone, Roth, Markus, Roulet, Esteban, Rovero, Adrian, Ruehl, Philip, Saftoiu, Alexandra, Saharan, Mohit, Salamida, Francesco, Salazar, Humberto, Salina, Gaetano, Sanabria Gomez, Jose, Sánchez, Federico, Moura Santos, Edivaldo, Santos, Eva, Sarazin, Fred, Sarmento, Raul, Sato, Ricardo, Savina, Pierpaolo, Schäfer, Christoph M., Scherini, Viviana, Schieler, Harald, Schimassek, Martin, Schimp, Michael, Schlüter, Felix, Schmidt, David, Scholten, Olaf, Schoorlemmer, Harm, Schovánek, Petr, Schröder, Frank G., Schulte, Josina, Schulz, Tobias, Sciutto, Sergio, Scornavacche, Marina, Segreto, Alberto, Sehgal, Srijan, Shellard, Ronald C., Sigl, Guenter, Silli, Gaia, Sima, Octavian, Smau, Raluca, Šmída, Radomir, Sommers, Paul, Soriano, Jorge F., Squartini, Ruben, Stadelmaier, Maximilian, Stanca, Denis, Stanič, Samo, Stasielak, Jaroslaw, Stassi, Patrick, Straub, Maximilian, Streich, Alexander, Suárez-Durán, Mauricio, Sudholz, Tristan, Suomijärvi, Tiina, Supanitsky, A. Daniel, Szadkowski, Zbigniew, Tapia, Alex, Taricco, Carla, Timmermans, Charles, Tkachenko, Olena, Tobiska, Petr, Todero Peixoto, Carlos J., Tomé, Bernardo, Torrès, Zoé, Travaini, Andres, Travnicek, Petr, Trimarelli, Caterina, Tueros, Matias, Ulrich, Ralf, Unger, Michael, Vaclavek, Lukáš, Vacula, Martin, Valdés Galicia, Jose F., Valore, Laura, Varela, Enrique, Vásquez-Ramírez, Adriana, Veberič, Darko, Ventura, Cynthia, Vergara Quispe, Indira D., Verzi, Valerio, Vicha, Jakub, Vink, Jacco, Vorobiov, Serguei, Wahlberg, Hernan, Watanabe, Clara, Watson, Alan, Weindl, Andreas, Wiencke, Lawrence, Wilczyński, Henryk, Wittkowski, David, Wundheiler, Brian, Yushkov, Alexey, Zapparrata, Orazio, Zas, Enrique, Zavrtanik, Danilo, Zavrtanik, Marko, and Zehrer, Lukas
- Subjects
flux ,observatory ,angular correlation ,cosmic radiation: energy ,anisotropy ,cosmic radiation: UHE ,Auger ,experimental results - Abstract
33 Seiten (2022).
- Published
- 2022
- Full Text
- View/download PDF
48. A Search for Photons with Energies Above 2 × 10$^{17}$ eV Using Hybrid Data from the Low-Energy Extensions of the Pierre Auger Observatory
- Author
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Abreu, Pedro, Aglietta, Marco, Albury, Justin M., Allekotte, Ingomar, Almeida Cheminant, Kevin, Almela, Alejandro, Alvarez-Muñiz, Jaime, Alves Batista, Rafael, Ammerman Yebra, Juan, Anastasi, Gioacchino Alex, Anchordoqui, Luis, Andrada, Belén, Andringa, Sofia, Aramo, Carla, Araújo Ferreira, Paulo Ricardo, Arnone, Enrico, Arteaga Velázquez, Juan Carlos, Asorey, Hernán Gonzalo, Assis, Pedro, Avila, Gualberto, Avocone, Emanuele, Badescu, Alina Mihaela, Bakalova, Alena, Balaceanu, Alexandru, Barbato, Felicia, Bellido, Jose A., Berat, Corinne, Bertaina, Mario Edoardo, Bhatta, Gopal, Biermann, Peter, Binet, Virginia, Bismark, Kathrin, Bister, Teresa Karolin, Biteau, Jonathan, Blazek, Jiri, Bleve, Carla, Blümer, Johannes, Boháčová, Martina, Boncioli, Denise, Bonifazi, Carla, Bonneau Arbeletche, Luan, Borodai, Nataliia, Botti, Ana Martina, Brack, Jeffrey, Bretz, Thomas, Brichetto Orchera, P. Gabriel, Briechle, Florian Lukas, Buchholz, Peter, Bueno, Antonio, Buitink, Stijn, Buscemi, Mario, Büsken, Max, Caballero-Mora, Karen S., Caccianiga, Lorenzo, Canfora, Fabrizia, Caracas, Ioana, Caruso, Rossella, Castellina, Antonella, Catalani, Fernando, Cataldi, Gabriella, Cazon, Lorenzo, Cerda, Marcos, Chinellato, Jose Augusto, Chudoba, Jiri, Chytka, Ladislav, Clay, Roger W., Cobos Cerutti, Agustín, Colalillo, Roberta, Coleman, Alan, Coluccia, Maria Rita, Conceição, Ruben, Condorelli, Antonio, Consolati, Giovanni, Contreras, Fernando, Convenga, Fabio, Correia dos Santos, Diego, Covault, Corbin, Dasso, Sergio, Daumiller, Kai, Dawson, Bruce R., Day, Jarryd A., de Almeida, Rogerio M., de Jesús, Joaquín, de Jong, Sijbrand J., de Mello Neto, J. R. T., De Mitri, Ivan, de Oliveira, Jaime, de Oliveira Franco, Danelise, de Palma, Francesco, de Souza, Vitor, De Vito, Emanuele, Del Popolo, Antonino, del Río, Mariano, Deligny, Olivier, Deval, Luca, di Matteo, Armando, Dobre, Madalina, Dobrigkeit, Carola, D'Olivo, Juan Carlos, Domingues Mendes, Luis Miguel, dos Anjos, Rita, Dova, Maria Teresa, Ebr, Jan, Engel, Ralph, Epicoco, Italo, Erdmann, Martin, Escobar, Carlos O., Etchegoyen, Alberto, Falcke, Heino, Farmer, John, Farrar, Glennys, Fauth, Anderson, Fazzini, Norberto, Feldbusch, Fridtjof, Fenu, Francesco, Fick, Brian, Figueira, Juan Manuel, Filipčič, Andrej, Fitoussi, Thomas, Fodran, Tomas, Fujii, Toshihiro, Fuster, Alan, Galea, Cristina, Galelli, Claudio, García, Beatriz, Garcia Vegas, Adrianna Luz, Gemmeke, Hartmut, Gesualdi, Flavia, Gherghel-Lascu, Alexandru, Ghia, Piera Luisa, Giaccari, Ugo, Giammarchi, Marco, Glombitza, Jonas, Gobbi, Fabian, Gollan, Fernando, Golup, Geraldina, Gómez Berisso, Mariano, Gómez Vitale, Primo F., Gongora, Juan Pablo, González, Juan Manuel, González, Nicolás, Goos, Isabel, Góra, Dariusz, Gorgi, Alessio, Gottowik, Marvin, Grubb, Trent D., Guarino, Fausto, Guedes, Germano, Guido, Eleonora, Hahn, Steffen, Hamal, Petr, Hampel, Matías Rolf, Hansen, Patricia, Harari, Diego, Harvey, Violet M., Haungs, Andreas, Hebbeker, Thomas, Heck, Dieter, Hill, Gary C., Hojvat, Carlos, Hörandel, Jörg, Horvath, Pavel, Hrabovský, Miroslav, Huege, Tim, Insolia, Antonio, Isar, Paula Gina, Janecek, Petr, Johnsen, Jeffrey A., Jurysek, Jakub, Kääpä, Alex, Kampert, Karl-Heinz, Keilhauer, Bianca, Khakurdikar, Abha, Kizakke Covilakam, Varada Varma, Klages, Hans, Kleifges, Matthias, Kleinfeller, Jonny, Knapp, Felix, Kunka, Norbert, Lago, Bruno L., Langner, Niklas Uwe, Leigui de Oliveira, Marcelo Augusto, Lenok, Vladimir, Letessier-Selvon, Antoine, Lhenry-Yvon, Isabelle, Lo Presti, Domenico, Lopes, Luis, López, Rebeca, Lu, Lu, Luce, Quentin, Lundquist, Jon Paul, Machado Payeras, Allan, Mancarella, Giovanni, Mandat, Dusan, Manning, Bradley C., Manshanden, Julien, Mantsch, Paul, Marafico, Sullivan, Mariani, Federico Maria, Mariazzi, Analisa, Mariş, Ioana, Marsella, Giovanni, Martello, Daniele, Martinelli, Sara, Martínez Bravo, Oscar, Mastrodicasa, Massimo, Mathes, Hermann-Josef, Matthews, James, Matthiae, Giorgio, Mayotte, Eric, Mayotte, Sonja, Mazur, Peter, Medina-Tanco, Gustavo, Melo, Diego, Menshikov, Alexander, Michal, Stanislav, Micheletti, Maria Isabel, Miramonti, Lino, Mollerach, Silvia, Montanet, François, Morejon, Leonel, Morello, Carlo, Mostafá, Miguel, Müller, Ana L., Muller, Marcio Aparecido, Mulrey, Katharine, Mussa, Roberto, Muzio, Marco, Namasaka, Wilson M., Nasr-Esfahani, Alina, Nellen, Lukas, Nicora, Gabriela, Niculescu-Oglinzanu, Mihai, Niechciol, Marcus, Nitz, Dave, Norwood, Ian, Nosek, Dalibor, Novotny, Vladimir, Nožka, Libor, Nucita, Achille, Núñez, Luis, Oliveira, Cainã, Palatka, Miroslav, Pallotta, Juan, Papenbreer, Philipp, Parente, Gonzalo, Parra, Alejandra, Pawlowsky, Jannis, Pech, Miroslav, Pękala, Jan, Pelayo, Rodrigo, Peña-Rodriguez, Jesús, Pereira Martins, Edyvania Emily, Perez Armand, Johnnier, Pérez Bertolli, Carmina, Perrone, Lorenzo, Petrera, Sergio, Petrucci, Camilla, Pierog, Tanguy, Pimenta, Mário, Pirronello, Valerio, Platino, Manuel, Pont, Bjarni, Pothast, Mart, Privitera, Paolo, Prouza, Michael, Puyleart, Andrew, Querchfeld, Sven, Rautenberg, Julian, Ravignani, Diego, Reininghaus, Maximilian, Ridky, Jan, Riehn, Felix, Risse, Markus, Rizi, Vincenzo, Rodrigues de Carvalho, Washington, Rodriguez Rojo, Jorge Rubén, Roncoroni, Matías J., Rossoni, Simone, Roth, Markus, Roulet, Esteban, Rovero, Adrian, Ruehl, Philip, Saftoiu, Alexandra, Saharan, Mohit, Salamida, Francesco, Salazar, Humberto, Salina, Gaetano, Sanabria Gomez, Jose, Sánchez, Federico, Moura Santos, Edivaldo, Santos, Eva, Sarazin, Fred, Sarmento, Raul, Sarmiento-Cano, Christian, Sato, Ricardo, Savina, Pierpaolo, Schäfer, Christoph M., Scherini, Viviana, Schieler, Harald, Schimassek, Martin, Schimp, Michael, Schlüter, Felix, Schmidt, David, Scholten, Olaf, Schoorlemmer, Harm, Schovánek, Petr, Schröder, Frank G., Schulte, Josina, Schulz, Tobias, Sciutto, Sergio, Scornavacche, Marina, Segreto, Alberto, Sehgal, Srijan, Shellard, Ronald C., Sigl, Guenter, Silli, Gaia, Sima, Octavian, Smau, Raluca, Šmída, Radomir, Sommers, Paul, Soriano, Jorge F., Squartini, Ruben, Stadelmaier, Maximilian, Stanca, Denis, Stanič, Samo, Stasielak, Jaroslaw, Stassi, Patrick, Streich, Alexander, Suárez-Durán, Mauricio, Sudholz, Tristan, Suomijärvi, Tiina, Supanitsky, A. Daniel, Szadkowski, Zbigniew, Tapia, Alex, Taricco, Carla, Timmermans, Charles, Tkachenko, Olena, Tobiska, Petr, Todero Peixoto, Carlos J., Tomé, Bernardo, Torrès, Zoé, Travaini, Andres, Travnicek, Petr, Trimarelli, Caterina, Tueros, Matias, Ulrich, Ralf, Unger, Michael, Vaclavek, Lukáš, Vacula, Martin, Valdés Galicia, Jose F., Valore, Laura, Varela, Enrique, Vásquez-Ramírez, Adriana, Veberič, Darko, Ventura, Cynthia, Vergara Quispe, Indira D., Verzi, Valerio, Vicha, Jakub, Vink, Jacco, Vorobiov, Serguei, Wahlberg, Hernan, Watanabe, Clara, Watson, Alan, Weindl, Andreas, Wiencke, Lawrence, Wilczyński, Henryk, Wittkowski, David, Wundheiler, Brian, Yushkov, Alexey, Zapparrata, Orazio, Zas, Enrique, Zavrtanik, Danilo, Zavrtanik, Marko, and Zehrer, Lukas
- Subjects
energy: high ,hybrid ,Non-thermal radiation sources (1119) ,Ultra-high-energy cosmic radiation (1733) ,UHE ,Auger ,observatory ,cosmic radiation ,gamma ray ,Multivariate analysis (1913) ,Cosmic-ray showers (327) ,Particle astrophysics (96) ,photon: flux - Abstract
15 Seiten (2022).
- Published
- 2022
- Full Text
- View/download PDF
49. Searches for Ultra-High-Energy Photons at the Pierre Auger Observatory
- Author
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Abreu, Pedro, Aglietta, Marco, Allekotte, Ingomar, Almeida Cheminant, Kevin, Almela, Alejandro, Alvarez-Muñiz, Jaime, Ammerman Yebra, Juan, Anastasi, Gioacchino Alex, Anchordoqui, Luis, Andrada, Belén, Andringa, Sofia, Aramo, Carla, Araújo Ferreira, Paulo Ricardo, Arnone, Enrico, Arteaga Velázquez, Juan Carlos, Asorey, Hernán Gonzalo, Assis, Pedro, Avila, Gualberto, Avocone, Emanuele, Badescu, Alina Mihaela, Bakalova, Alena, Balaceanu, Alexandru, Barbato, Felicia, Bellido, Jose A., Berat, Corinne, Bertaina, Mario Edoardo, Bhatta, Gopal, Biermann, Peter, Binet, Virginia, Bismark, Kathrin, Bister, Teresa Karolin, Biteau, Jonathan, Blazek, Jiri, Bleve, Carla, Blümer, Johannes, Boháčová, Martina, Boncioli, Denise, Bonifazi, Carla, Bonneau Arbeletche, Luan, Borodai, Nataliia, Brack, Jeffrey, Bretz, Thomas, Brichetto Orchera, P. Gabriel, Briechle, Florian Lukas, Buchholz, Peter, Bueno, Antonio, Buitink, Stijn, Buscemi, Mario, Büsken, Max, Bwembya, Anthony, Caballero-Mora, Karen S., Caccianiga, Lorenzo, Caracas, Ioana, Caruso, Rossella, Castellina, Antonella, Catalani, Fernando, Cataldi, Gabriella, Cazon, Lorenzo, Cerda, Marcos, Chinellato, Jose Augusto, Chudoba, Jiri, Chytka, Ladislav, Clay, Roger W., Cobos Cerutti, Agustín, Colalillo, Roberta, Coleman, Alan, Coluccia, Maria Rita, Conceição, Ruben, Condorelli, Antonio, Consolati, Giovanni, Contreras, Fernando, Convenga, Fabio, Correia dos Santos, Diego, Covault, Corbin, Cristinziani, Markus, Dasso, Sergio, Daumiller, Kai, Dawson, Bruce R., de Almeida, Rogerio M., de Jesús, Joaquín, de Jong, Sijbrand J., de Mello Neto, Joao, De Mitri, Ivan, de Oliveira, Jaime, de Oliveira Franco, Danelise, de Palma, Francesco, de Souza, Vitor, De Vito, Emanuele, Del Popolo, Antonino, Deligny, Olivier, Deval, Luca, di Matteo, Armando, Dobre, Madalina, Dobrigkeit, Carola, D'Olivo, Juan Carlos, Domingues Mendes, Luis Miguel, dos Anjos, Rita, Ebr, Jan, Eman, Mohamed, Engel, Ralph, Epicoco, Italo, Erdmann, Martin, Etchegoyen, Alberto, Falcke, Heino, Farmer, John, Farrar, Glennys, Fauth, Anderson, Fazzini, Norberto, Feldbusch, Fridtjof, Fenu, Francesco, Fick, Brian, Figueira, Juan Manuel, Filipčič, Andrej, Fitoussi, Thomas, Fodran, Tomas, Fujii, Toshihiro, Fuster, Alan, Galea, Cristina, Galelli, Claudio, García, Beatriz, Gemmeke, Hartmut, Gesualdi, Flavia, Gherghel-Lascu, Alexandru, Ghia, Piera Luisa, Giaccari, Ugo, Giammarchi, Marco, Glombitza, Jonas, Gobbi, Fabian, Gollan, Fernando, Golup, Geraldina, Gómez Berisso, Mariano, Gómez Vitale, Primo F., Gongora, Juan Pablo, González, Juan Manuel, González, Nicolás, Goos, Isabel, Góra, Dariusz, Gorgi, Alessio, Gottowik, Marvin, Grubb, Trent D., Guarino, Fausto, Guedes, Germano, Guido, Eleonora, Hahn, Steffen, Hamal, Petr, Hampel, Matías Rolf, Hansen, Patricia, Harari, Diego, Harvey, Violet M., Haungs, Andreas, Hebbeker, Thomas, Heck, Dieter, Hojvat, Carlos, Hörandel, Jörg, Horvath, Pavel, Hrabovský, Miroslav, Huege, Tim, Insolia, Antonio, Isar, Paula Gina, Janecek, Petr, Johnsen, Jeffrey A., Jurysek, Jakub, Kääpä, Alex, Kampert, Karl-Heinz, Keilhauer, Bianca, Khakurdikar, Abha, Kizakke Covilakam, Varada Varma, Klages, Hans, Kleifges, Matthias, Kleinfeller, Jonny, Knapp, Felix, Kunka, Norbert, Lago, Bruno L., Langner, Niklas Uwe, Leigui de Oliveira, Marcelo Augusto, Lenok, Vladimir, Letessier-Selvon, Antoine, Lhenry-Yvon, Isabelle, Lo Presti, Domenico, Lopes, Luis, López, Rebeca, Lu, Lu, Luce, Quentin, Lundquist, Jon Paul, Machado Payeras, Allan, Mancarella, Giovanni, Mandat, Dusan, Manning, Bradley C., Manshanden, Julien, Mantsch, Paul, Marafico, Sullivan, Mariani, Federico Maria, Mariazzi, Analisa, Mariş, Ioana, Marsella, Giovanni, Martello, Daniele, Martinelli, Sara, Martínez Bravo, Oscar, Martins, Miguel A., Mastrodicasa, Massimo, Mathes, Hermann-Josef, Matthews, James, Matthiae, Giorgio, Mayotte, Eric, Mayotte, Sonja, Mazur, Peter, Medina-Tanco, Gustavo, Melo, Diego, Menshikov, Alexander, Michal, Stanislav, Micheletti, Maria Isabel, Miramonti, Lino, Mollerach, Silvia, Montanet, François, Morejon, Leonel, Morello, Carlo, Müller, Ana L., Mulrey, Katharine, Mussa, Roberto, Muzio, Marco, Namasaka, Wilson M., Nasr-Esfahani, Alina, Nellen, Lukas, Nicora, Gabriela, Niculescu-Oglinzanu, Mihai, Niechciol, Marcus, Nitz, Dave, Norwood, Ian, Nosek, Dalibor, Novotny, Vladimir, Nožka, Libor, Nucita, Achille, Núñez, Luis, Oliveira, Cainã, Palatka, Miroslav, Pallotta, Juan, Parente, Gonzalo, Parra, Alejandra, Pawlowsky, Jannis, Pech, Miroslav, Pękala, Jan, Pelayo, Rodrigo, Pereira Martins, Edyvania Emily, Perez Armand, Johnnier, Pérez Bertolli, Carmina, Perrone, Lorenzo, Petrera, Sergio, Petrucci, Camilla, Pierog, Tanguy, Pimenta, Mário, Platino, Manuel, Pont, Bjarni, Pothast, Mart, Pourmohammad Shavar, Mohsen, Privitera, Paolo, Prouza, Michael, Puyleart, Andrew, Querchfeld, Sven, Rautenberg, Julian, Ravignani, Diego, Reininghaus, Maximilian, Ridky, Jan, Riehn, Felix, Risse, Markus, Rizi, Vincenzo, Rodrigues de Carvalho, Washington, Rodriguez Rojo, Jorge Rubén, Roncoroni, Matías J., Rossoni, Simone, Roth, Markus, Roulet, Esteban, Rovero, Adrian, Ruehl, Philip, Saftoiu, Alexandra, Saharan, Mohit, Salamida, Francesco, Salazar, Humberto, Salina, Gaetano, Sanabria Gomez, Jose, Sánchez, Federico, Moura Santos, Edivaldo, Santos, Eva, Sarazin, Fred, Sarmento, Raul, Sato, Ricardo, Savina, Pierpaolo, Schäfer, Christoph M., Scherini, Viviana, Schieler, Harald, Schimassek, Martin, Schimp, Michael, Schlüter, Felix, Schmidt, David, Scholten, Olaf, Schoorlemmer, Harm, Schovánek, Petr, Schröder, Frank G., Schulte, Josina, Schulz, Tobias, Sciutto, Sergio, Scornavacche, Marina, Segreto, Alberto, Sehgal, Srijan, Shivashankara, Shima Ujjani, Sigl, Guenter, Silli, Gaia, Sima, Octavian, Smau, Raluca, Šmída, Radomir, Sommers, Paul, Soriano, Jorge F., Squartini, Ruben, Stadelmaier, Maximilian, Stanca, Denis, Stanič, Samo, Stasielak, Jaroslaw, Stassi, Patrick, Straub, Maximilian Philipp, Streich, Alexander, Suárez-Durán, Mauricio, Sudholz, Tristan, Suomijärvi, Tiina, Supanitsky, A. Daniel, Szadkowski, Zbigniew, Tapia, Alex, Taricco, Carla, Timmermans, Charles, Tkachenko, Olena, Tobiska, Petr, Todero Peixoto, Carlos J., Tomé, Bernardo, Torrès, Zoé, Travaini, Andres, Travnicek, Petr, Trimarelli, Caterina, Tueros, Matias, Ulrich, Ralf, Unger, Michael, Vaclavek, Lukáš, Vacula, Martin, Valdés Galicia, Jose F., Valore, Laura, Varela, Enrique, Vásquez-Ramírez, Adriana, Veberič, Darko, Ventura, Cynthia, Vergara Quispe, Indira D., Verzi, Valerio, Vicha, Jakub, Vink, Jacco, Vorobiov, Serguei, Watanabe, Clara, Watson, Alan, Weindl, Andreas, Wiencke, Lawrence, Wilczyński, Henryk, Wittkowski, David, Wundheiler, Brian, Yushkov, Alexey, Zapparrata, Orazio, Zas, Enrique, Zavrtanik, Danilo, Zavrtanik, Marko, Zehrer, Lukas, The Pierre Auger Collaboration, Abreu, P, Aglietta, M, Allekotte, I, Cheminant, Ka, Almela, A, Alvarez-Muniz, J, Yebra, Ja, Anastasi, Ga, Anchordoqui, L, Andrada, B, Andringa, S, Aramo, C, Ferreira, Pra, Arnone, E, Velazquez, Jca, Asorey, H, Assis, P, Avila, G, Avocone, E, Badescu, Am, Bakalova, A, Balaceanu, A, Barbato, F, Bellido, Ja, Berat, C, Bertaina, Me, Bhatta, G, Biermann, Pl, Binet, V, Bismark, K, Bister, T, Biteau, J, Blazek, J, Bleve, C, Blumer, J, Bohacova, M, Boncioli, D, Bonifazi, C, Arbeletche, Lb, Borodai, N, Brack, J, Bretz, T, Orchera, Pgb, Briechle, Fl, Buchholz, P, Bueno, A, Buitink, S, Buscemi, M, Busken, M, Bwembya, A, Caballero-Mora, K, Caccianiga, L, Caracas, I, Caruso, R, Castellina, A, Catalani, F, Cataldi, G, Cazon, L, Cerda, M, Chinellato, Ja, Chudoba, J, Chytka, L, Clay, Rw, Cerutti, Acc, Colalillo, R, Coleman, A, Coluccia, Mr, Conceicao, R, Condorelli, A, Consolati, G, Contreras, F, Convenga, F, dos Santos, Dc, Covault, Ce, Cristinziani, M, Dasso, S, Daumiller, K, Dawson, Br, de Almeida, Rm, de Jesus, J, de Jong, Sj, Neto, Jrtd, De Mitri, I, de Oliveira, J, Franco, Dd, de Palma, F, de Souza, V, De Vito, E, Del Popolo, A, Deligny, O, Deval, L, di Matteo, A, Dobre, M, Dobrigkeit, C, D'Olivo, Jc, Mendes, Lmd, dos Anjos, Rc, Ebr, J, Eman, M, Engel, R, Epicoco, I, Erdmann, M, Etchegoyen, A, Falcke, H, Farmer, J, Farrar, G, Fauth, Ac, Fazzini, N, Feldbusch, F, Fenu, F, Fick, B, Figueira, Jm, Filipcic, A, Fitoussi, T, Fodran, T, Fujii, T, Fuster, A, Galea, C, Galelli, C, Garcia, B, Gemmeke, H, Gesualdi, F, Gherghel-Lascu, A, Ghia, Pl, Giaccari, U, Giammarchi, M, Glombitza, J, Gobbi, F, Gollan, F, Golup, G, Berisso, Mg, Vitale, Pfg, Gongora, Jp, Gonzalez, Jm, Gonzalez, N, Goos, I, Gora, D, Gorgi, A, Gottowik, M, Grubb, Td, Guarino, F, Guedes, Gp, Guido, E, Hahn, S, Hamal, P, Hampel, Mr, Hansen, P, Harari, D, Harvey, Vm, Haungs, A, Hebbeker, T, Heck, D, Hojvatd, C, Horandel, Jr, Horvath, P, Hrabovsky, M, Huege, T, Insolia, A, Isar, Pg, Janecek, P, Johnsen, Ja, Jurysek, J, Kaapa, A, Kampert, Kh, Keilhauer, B, Khakurdikar, A, Covilakam, Vvk, Klages, Ho, Kleifges, M, Kleinfeller, J, Knapp, F, Kunka, N, Lago, Bl, Langner, N, de Oliveira, Mal, Lenok, V, Letessier-Selvon, A, Lhenry-Yvon, I, Lo Presti, D, Lopes, L, Lopez, R, Lu, L, Luce, Q, Lundquist, Jp, Payeras, Am, Mancarella, G, Mandat, D, Manning, Bc, Manshan-den, J, Mantschd, P, Marafico, S, Mariani, Fm, Mariazzi, Ag, Maris, Ic, Marsella, G, Martello, D, Martinelli, S, Bravo, Om, Martins, Ma, Mastrodicasa, M, Mathes, Hj, Matthews, J, Matthiae, G, May-otte, E, Mayotte, S, Mazurd, Po, Medina-Tanco, G, Melo, D, Menshikov, A, Michal, S, Micheletti, Mi, Miramonti, L, Mollerach, S, Montanet, F, Morejon, L, Morello, C, Muller, Al, Mulrey, K, Mussa, R, Muzio, M, Namasaka, Wm, Nasr-Esfahani, A, Nellen, L, Nicora, G, Niculescu-Oglinzanu, M, Niechciol, M, Nitz, D, Norwood, I, Nosek, D, Novotny, V, Nozka, L, Nucita, A, Nunez, La, Oliveira, C, Palatka, M, Pallotta, J, Parente, G, Parra, A, Pawlowsky, J, Pech, M, Pelayo, R, Martins, Eep, Armand, Jp, Bertolli, Cp, Perrone, L, Petrera, S, Petrucci, C, Pierog, T, Pimenta, M, Platino, M, Pont, B, Pothast, M, Shavar, Mp, Privitera, P, Prouza, M, Puyleart, A, Querchfeld, S, Rautenberg, J, Ravignani, D, Reininghaus, M, Ridky, J, Riehn, F, Risse, M, Rizi, V, de Carvalho, Wr, Rojo, Jr, Roncoroni, Mj, Rossoni, S, Roth, M, Roulet, E, Rovero, Ac, Ruehl, P, Saftoiu, A, Saharan, M, Salamida, F, Salazar, H, Salina, G, Gomez, Jd, Sanchez, F, Santos, Em, Santos, E, Sarazin, F, Sarmento, R, Sato, R, Sav-ina, P, Schafer, Cm, Scherini, V, Schieler, H, Schimassek, M, Schimp, M, Schluter, F, Schmidt, D, Scholten, O, Schoorlemmer, H, Schovanek, P, Schroder, Fg, Schulte, J, Schulz, T, Sciutto, Sj, Scornavacche, M, Segreto, A, Sehgal, S, Shivashankara, Su, Sigl, G, Silli, G, Sima, O, Smau, R, Smida, R, Sommersh, P, Soriano, Jf, Squartini, R, Stadelmaier, M, Stanca, D, Stanic, S, Stasielak, J, Stassi, P, Straub, M, Streich, A, Suarez-Duran, M, Sudholz, T, Suomijarvi, T, Supanitsky, Ad, Szadkowski, Z, Tapia, A, Taricco, C, Timmermans, C, Tkachenko, O, Tobiska, P, Peixoto, Cjt, Tome, B, Torres, Z, Travaini, A, Travnicek, P, Trimarelli, C, Tueros, M, Ulrich, R, Unger, M, Vaclavek, L, Vacula, M, Galicia, Jfv, Valore, L, Varela, E, Vasquez-Ramirez, A, Veberic, D, Ventura, C, Quispe, Idv, Verzi, V, Vicha, J, Vink, J, Vorobiov, S, Watanabe, C, Watson, Aa, Weindl, A, Wiencke, L, Wilczynski, H, Wittkowski, D, Wundheiler, B, Yushkov, A, Zapparrata, O, Zas, E, Zavrtanik, D, Zavrtanik, M, and Zehrer, L
- Subjects
transients ,Astronomy ,FOS: Physical sciences ,General Physics and Astronomy ,Photons, ultra-high energies, air showers, Pierre Auger Observatory, upper limits, transients ,photons ,ultra-high energies ,air showers ,Pierre Auger Observatory ,upper limits ,Transients ,Air showers ,ddc:530 ,High Energy Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Photons ,showers: atmosphere ,Ultra-high energies ,photon ,gravitational radiation ,ASTROFÍSICA ,UHE [gamma ray] ,Upper limits ,Auger ,flux ,observatory ,neutral particle ,gamma ray: UHE ,Experimental High Energy Physics ,Astrophysics - High Energy Astrophysical Phenomena ,atmosphere [showers] - Abstract
The Pierre Auger Observatory, which is the largest air-shower experiment in the world, offers unprecedented exposure to neutral particles at the highest energies. Since the start of data collection more than 18 years ago, various searches for ultra-high-energy (UHE, E & 1017 eV) photons have been performed, either for a diffuse flux of UHE photons, for point sources of UHE photons or for UHE photons associated with transient events such as gravitational wave events. In the present paper, we summarize these searches and review the current results obtained using the wealth of data collected by the Pierre Auger Observatory., Argentina-Comision Nacional de Energia Atomica, ANPCyT, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Gobierno de la Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings, Valle Las Lenas, Australian Research Council, Belgium-Fonds de la Recherche Scientifique (FNRS), FWO, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) Financiadora de Inovacao e Pesquisa (Finep) Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2019/10151-2 2010/07359-6 1999/05404-3, Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (MCTIC), France-Centre de Calcul IN2P3/CNRS Centre National de la Recherche Scientifique (CNRS) Region Ile-de-France Centre National de la Recherche Scientifique (CNRS) Departement Sciences de l'Univers (SDU-INSU/CNRS) French National Research Agency (ANR) LABEX ANR-10-LABX-63 ANR-11-IDEX-0004-02, Federal Ministry of Education & Research (BMBF) German Research Foundation (DFG) Finanzministerium Baden-Wurttemberg Helmholtz Alliance for Astroparticle Physics (HAP) Helmholtz Association Ministerium fur Kultur und Wissenschaft des Landes Nordrhein-Westfalen Ministerium fur Wissenschaft, Forschung und Kunst des Landes Baden-Wurttemberg, Italy-Istituto Nazionale di Fisica Nucleare (INFN) Istituto Nazionale Astrofisica (INAF), Ministry of Education, Universities and Research (MIUR), CETEMPS Center of Excellence, Ministry of Foreign Affairs and International Cooperation (Italy), Consejo Nacional de Ciencia y Tecnologia (CONACyT) 167733 Universidad Nacional Autonoma de Mexico Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) Universidad Nacional Autonoma de Mexico, Netherlands-Ministry of Education, Culture and Science Netherlands Organization for Scientific Research (NWO), SURF Cooperative, Poland-Ministry of Education and Science DIR/WK/2018/11 National Science Centre, Poland 2016/22/M/ST9/00198 2016/23/B/ST9/01635 2020/39/B/ST9/01398, Portuguese Foundation for Science and Technology FEDER funds within Programa Operacional Factores de Competitividade through FundacAo para a Ciencia e a Tecnologia (COMPETE), Romania-Ministry of Research, Innovation and Digitization, CNCS/CCCDI UEFISCDI within the National Nucleus Program PN19150201/16N/2019 PN1906010 PNCDI III TE128 PN-III-P1-1.1-TE-2021-0924/TE57/2022 PED289, Slovenian Research Agency - Slovenia P1-0031 P1-0385 I0-0033 N1-0111, Spanish Government FPA2017-85114-P PID2019-104676GB-C32, Xunta de Galicia, European Commission ED431C 2017/07, Junta de Andalucia SOMM17/6104/UGR P18-FR-4314, European Commission, RENATA Red Nacional Tematica de Astroparticulas FPA2015-68783-REDT, Maria de Maeztu Unit of Excellence MDM-2016-0692, United States Department of Energy (DOE) DE-AC02-07CH11359 DE-FR02-04ER41300 DE-FG02-99ER41107 DE-SC0011689, National Science Foundation (NSF) 0450696, Grainger Foundation, Marie Curie-IRSES/EPLANET, European Particle Physics Latin American Network, UNESCO, MSMT CR LTT18004 LM2015038 LM2018102 CZ.02.1.01/0.0/0.0/16_013/0001402 CZ.02.1.01/0.0/0.0/18_046/0016010 CZ.02.1.01/0.0/0.0/17_049/0008422
- Published
- 2022
50. Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory
- Author
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The Pierre Auger Collaboration, Abreu, Pedro, Anchordoqui, Luis, dos Anjos, Rita, Dova, Maria Teresa, Ebr, Jan, Engel, Ralph, Epicoco, Italo, Erdmann, Martin, Escobar, Carlos O., Etchegoyen, Alberto, Falcke, Heino, Farmer, John, Andrada, Belén, Farrar, Glennys, Fauth, Anderson, Fazzini, Norberto, Feldbusch, Fridtjof, Fenu, Francesco, Fick, Brian, Figueira, Juan Manuel, Filipčič, Andrej, Fitoussi, Thomas, Fodran, Tomas, Andringa, Sofia, Fujii, Toshihiro, Fuster, Alan, Galea, Cristina, Galelli, Claudio, García, Beatriz, Garcia Vegas, Adrianna Luz, Gemmeke, Hartmut, Gesualdi, Flavia, Gherghel-Lascu, Alexandru, Ghia, Piera Luisa, Aramo, Carla, Giaccari, Ugo, Giammarchi, Marco, Glombitza, Jonas, Gobbi, Fabian, Gollan, Fernando, Golup, Geraldina, Gómez Berisso, Mariano, Gómez Vitale, Primo F., Gongora, Juan Pablo, González, Juan Manuel, Araújo Ferreira, Paulo Ricardo, González, Nicolás, Goos, Isabel, Góra, Dariusz, Gorgi, Alessio, Gottowik, Marvin, Grubb, Trent D., Guarino, Fausto, Guedes, Germano, Guido, Eleonora, Hahn, Steffen, Arnone, Enrico, Hamal, Petr, Hampel, Matías Rolf, Hansen, Patricia, Harari, Diego, Harvey, Violet M., Haungs, Andreas, Hebbeker, Thomas, Heck, Dieter, Hill, Gary C., Hojvat, Carlos, Arteaga Velázquez, Juan Carlos, Hörandel, Jörg, Horvath, Pavel, Hrabovský, Miroslav, Huege, Tim, Insolia, Antonio, Isar, Paula Gina, Janecek, Petr, Johnsen, Jeffrey A., Jurysek, Jakub, Kääpä, Alex, Asorey, Hernán Gonzalo, Kampert, Karl-Heinz, Karastathis, Nikolaos, Keilhauer, Bianca, Khakurdikar, Abha, Kizakke Covilakam, Varada Varma, Klages, Hans, Kleifges, Matthias, Kleinfeller, Jonny, Knapp, Felix, Kunka, Norbert, Assis, Pedro, Lago, Bruno L., Lang, Rodrigo Guedes, Langner, Niklas Uwe, Leigui de Oliveira, Marcelo Augusto, Lenok, Vladimir, Letessier-Selvon, Antoine, Lhenry-Yvon, Isabelle, Lo Presti, Domenico, Lopes, Luis, López, Rebeca, Avila, Gualberto, Lu, Lu, Luce, Quentin, Lundquist, Jon Paul, Machado Payeras, Allan, Mancarella, Giovanni, Mandat, Dusan, Manning, Bradley C., Manshanden, Julien, Mantsch, Paul, Marafico, Sullivan, Aglietta, Marco, Badescu, Alina Mihaela, Mariani, Federico Maria, Mariazzi, Analisa, Mariş, Ioana, Marsella, Giovanni, Martello, Daniele, Martinelli, Sara, Martínez Bravo, Oscar, Mastrodicasa, Massimo, Mathes, Hermann-Josef, Matthews, James, Bakalova, Alena, Matthiae, Giorgio, Mayotte, Eric, Mayotte, Sonja, Mazur, Peter, Medina-Tanco, Gustavo, Melo, Diego, Menshikov, Alexander, Michal, Stanislav, Micheletti, Maria Isabel, Miramonti, Lino, Balaceanu, Alexandru, Mollerach, Silvia, Montanet, François, Morejon, Leonel, Morello, Carlo, Mostafá, Miguel, Müller, Ana L., Muller, Marcio Aparecido, Mulrey, Katharine, Mussa, Roberto, Muzio, Marco, Barbato, Felicia, Namasaka, Wilson M., Nasr-Esfahani, Alina, Nellen, Lukas, Nicora, Gabriela, Niculescu-Oglinzanu, Mihai, Niechciol, Marcus, Nitz, Dave, Nosek, Dalibor, Novotny, Vladimir, Nožka, Libor, Bellido, Jose A., Nucita, Achille, Núñez, Luis, Oliveira, Cainã, Palatka, Miroslav, Pallotta, Juan, Papenbreer, Philipp, Parente, Gonzalo, Parra, Alejandra, Pawlowsky, Jannis, Pech, Miroslav, Berat, Corinne, Pękala, Jan, Pelayo, Rodrigo, Peña-Rodriguez, Jesús, Pereira Martins, Edyvania Emily, Perez Armand, Johnnier, Pérez Bertolli, Carmina, Perlin, Matías, Perrone, Lorenzo, Petrera, Sergio, Petrucci, Camilla, Bertaina, Mario Edoardo, Pierog, Tanguy, Pimenta, Mário, Pirronello, Valerio, Platino, Manuel, Pont, Bjarni, Pothast, Mart, Privitera, Paolo, Prouza, Michael, Puyleart, Andrew, Querchfeld, Sven, Bertou, Xavier, Rautenberg, Julian, Ravignani, Diego, Reininghaus, Maximilian, Ridky, Jan, Riehn, Felix, Risse, Markus, Rizi, Vincenzo, Rodrigues de Carvalho, Washington, Rodriguez Rojo, Jorge Rubén, Roncoroni, Matías J., Bhatta, Gopal, Rossoni, Simone, Roth, Markus, Roulet, Esteban, Rovero, Adrian, Ruehl, Philip, Saftoiu, Alexandra, Saharan, Mohit, Salamida, Francesco, Salazar, Humberto, Salina, Gaetano, Biermann, Peter, Sanabria Gomez, Jose, Sánchez, Federico, Santos, Edivaldo Moura, Santos, Eva, Sarazin, Fred, Sarmento, Raul, Sarmiento-Cano, Christian, Sato, Ricardo, Savina, Pierpaolo, Schäfer, Christoph M., Albury, Justin M., Binet, Virginia, Scherini, Viviana, Schieler, Harald, Schimassek, Martin, Schimp, Michael, Schlüter, Felix, Schmidt, David, Scholten, Olaf, Schoorlemmer, Harm, Schovánek, Petr, Schröder, Frank G., Bismark, Kathrin, Schulte, Josina, Schulz, Tobias, Sciutto, Sergio, Scornavacche, Marina, Segreto, Alberto, Sehgal, Srijan, Shellard, Ronald C., Sigl, Guenter, Silli, Gaia, Sima, Octavian, Bister, Teresa Karolin, Smau, Raluca, Šmída, Radomir, Sommers, Paul, Soriano, Jorge F., Squartini, Ruben, Stadelmaier, Maximilian, Stanca, Denis, Stanič, Samo, Stasielak, Jaroslaw, Stassi, Patrick, Biteau, Jonathan, Streich, Alexander, Suárez-Durán, Mauricio, Sudholz, Tristan, Suomijärvi, Tiina, Supanitsky, A. Daniel, Szadkowski, Zbigniew, Tapia, Alex, Taricco, Carla, Timmermans, Charles, Tkachenko, Olena, Blazek, Jiri, Tobiska, Petr, Todero Peixoto, Carlos J., Tomé, Bernardo, Torrès, Zoé, Travaini, Andres, Travnicek, Petr, Trimarelli, Caterina, Tueros, Matias, Ulrich, Ralf, Unger, Michael, Bleve, Carla, Vaclavek, Lukáš, Vacula, Martin, Valdés Galicia, Jose F., Valore, Laura, Varela, Enrique, Vásquez-Ramírez, Adriana, Veberič, Darko, Ventura, Cynthia, Vergara Quispe, Indira D., Verzi, Valerio, Blümer, Johannes, Vicha, Jakub, Vink, Jacco, Vorobiov, Serguei, Wahlberg, Hernan, Watanabe, Clara, Watson, Alan, Weindl, Andreas, Wiencke, Lawrence, Wilczyński, Henryk, Wittkowski, David, Boháčová, Martina, Wundheiler, Brian, Yushkov, Alexey, Zapparrata, Orazio, Zas, Enrique, Zavrtanik, Danilo, Zavrtanik, Marko, Zehrer, Lukas, Boncioli, Denise, Bonifazi, Carla, Allekotte, Ingomar, Bonneau Arbeletche, Luan, Borodai, Nataliia, Botti, Ana Martina, Brack, Jeffrey, Bretz, Thomas, Brichetto Orchera, P. Gabriel, Briechle, Florian Lukas, Buchholz, Peter, Bueno, Antonio, Buitink, Stijn, Almeida Cheminant, Kevin, Buscemi, Mario, Büsken, Max, Caballero-Mora, Karen S., Caccianiga, Lorenzo, Canfora, Fabrizia, Caracas, Ioana, Caruso, Rossella, Castellina, Antonella, Catalani, Fernando, Cataldi, Gabriella, Almela, Alejandro, Cazon, Lorenzo, Cerda, Marcos, Chinellato, Jose Augusto, Chudoba, Jiri, Chytka, Ladislav, Clay, Roger W., Cobos Cerutti, Agustín, Colalillo, Roberta, Coleman, Alan, Coluccia, Maria Rita, Alvarez-Muñiz, Jaime, Conceição, Ruben, Condorelli, Antonio, Consolati, Giovanni, Contreras, Fernando, Convenga, Fabio, Correia dos Santos, Diego, Covault, Corbin, Dasso, Sergio, Daumiller, Kai, Dawson, Bruce R., Alves Batista, Rafael, Day, Jarryd A., de Almeida, Rogerio M., de Jesús, Joaquín, de Jong, Sijbrand J., de Mello Neto, J. R. T., De Mitri, Ivan, de Oliveira, Jaime, de Oliveira Franco, Danelise, de Palma, Francesco, de Souza, Vitor, Anastasi, Gioacchino Alex, De Vito, Emanuele, Del Popolo, Antonino, del Río, Mariano, Deligny, Olivier, Deval, Luca, di Matteo, Armando, Dobre, Madalina, Dobrigkeit, Carola, D'Olivo, Juan Carlos, Domingues Mendes, Luis Miguel, High Energy Astrophys. & Astropart. Phys (API, FNWI), Physics, Abreu P., Aglietta M., Albury J.M., Allekotte I., Almeida cheminant K., Almela A., Alvarez-Muniz J., Alves batista R., Anastasi G.A., Anchordoqui L., Andrada B., Andringa S., Aramo C., Araujo ferreira P.R., Arnone E., Arteaga velazquez J.C., Asorey H., Assis P., Avila G., Badescu A.M., Bakalova A., Balaceanu A., Barbato F., Bellido J.A., Berat C., Bertaina M.E., Bertou X., Bhatta G., Biermann P.L., Binet V., Bismark K., Bister T., Biteau J., Blazek J., Bleve C., Blumer J., Bohacova M., Boncioli D., Bonifazi C., Bonneau arbeletche L., Borodai N., Botti A.M., Brack J., Bretz T., Brichetto orchera P.G., Briechle F.L., Buchholz P., Bueno A., Buitink S., Buscemi M., Busken M., Caballero-Mora K.S., Caccianiga L., Canfora F., Caracas I., Caruso R., Castellina A., Catalani F., Cataldi G., Cazon L., Cerda M., Chinellato J.A., Chudoba J., Chytka L., Clay R.W., Cobos cerutti A.C., Colalillo R., Coleman A., Coluccia M.R., Concei o R., Condorelli A., Consolati G., Contreras F., Convenga F., Correia dos santos D., Covault C.E., Dasso S., Daumiller K., Dawson B.R., Day J.A., De almeida R.M., De jesus J., De jong S.J., De mello neto J.R.T., De mitri I., De oliveira J., De oliveira franco D., De palma F., De souza V., De vito E., Del popolo A., Del rio M., Deligny O., Deval L., Di matteo A., Dobre M., Dobrigkeit C., D'olivo J.C., Domingues mendes L.M., Dos anjos R.C., Dova M.T., Ebr J., Engel R., Epicoco I., Erdmann M., Escobar C.O., Etchegoyen A., Falcke H., Farmer J., Farrar G., Fauth A.C., Fazzini N., Feldbusch F., Fenu F., Fick B., Figueira J.M., Filipcic A., Fitoussi T., Fodran T., Fujii T., Fuster A., Galea C., Galelli C., Garcia B., Garcia vegas A.L., Gemmeke H., Gesualdi F., Gherghel-Lascu A., Ghia P.L., Giaccari U., Giammarchi M., Glombitza J., Gobbi F., Gollan F., Golup G., Gomez berisso M., Gomez vitale P.F., Gongora J.P., Gonzalez J.M., Gonzalez N., Goos I., Gora D., Gorgi A., Gottowik M., Grubb T.D., Guarino F., Guedes G.P., Guido E., Hahn S., Hamal P., Hampel M.R., Hansen P., Harari D., Harvey V.M., Haungs A., Hebbeker T., Heck D., Hill G.C., Hojvat C., Horandel J.R., Horvath P., Hrabovsky M., Huege T., Insolia A., Isar P.G., Janecek P., Johnsen J.A., Jurysek J., Kp A., Kampert K.H., Karastathis N., Keilhauer B., Khakurdikar A., Kizakke covilakam V.V., Klages H.O., Kleifges M., Kleinfeller J., Knapp F., Kunka N., Lago B.L., Lang R.G., Langner N., Leigui de oliveira M.A., Lenok V., Letessier-Selvon A., Lhenry-Yvon I., Lo presti D., Lopes L., Lopez R., Lu L., Luce Q., Lundquist J.P., Machado payeras A., Mancarella G., Mandat D., Manning B.C., Manshanden J., Mantsch P., Marafico S., Mariani F.M., Mariazzi A.G., Maris I.C., Marsella G., Martello D., Martinelli S., Martinez bravo O., Mastrodicasa M., Mathes H.J., Matthews J., Matthiae G., Mayotte E., Mayotte S., Mazur P.O., Medina-Tanco G., Melo D., Menshikov A., Michal S., Micheletti M.I., Miramonti L., Mollerach S., Montanet F., Morejon L., Morello C., Mostafa M., Muller A.L., Muller M.A., Mulrey K., Mussa R., Muzio M., Namasaka W.M., Nasr-Esfahani A., Nellen L., Nicora G., Niculescu-Oglinzanu M., Niechciol M., Nitz D., Nosek D., Novotny V., Nozka L., Nucita A., Nunez L.A., Oliveira C., Palatka M., Pallotta J., Papenbreer P., Parente G., Parra A., Pawlowsky J., Pech M., Pkala J., Pelayo R., Pena-Rodriguez J., Pereira martins E.E., Perez armand J., Perez bertolli C., Perlin M., Perrone L., Petrera S., Petrucci C., Pierog T., Pimenta M., Pirronello V., Platino M., Pont B., Pothast M., Privitera P., Prouza M., Puyleart A., Querchfeld S., Rautenberg J., Ravignani D., Reininghaus M., Ridky J., Riehn F., Risse M., Rizi V., Rodrigues de carvalho W., Rodriguez rojo J., Roncoroni M.J., Rossoni S., Roth M., Roulet E., Rovero A.C., Ruehl P., Saftoiu A., Saharan M., Salamida F., Salazar H., Salina G., Sanabria gomez J.D., Sanchez F., Santos E.M., Santos E., Sarazin F., Sarmento R., Sarmiento-Cano C., Sato R., Savina P., Sch fer C.M., Scherini V., Schieler H., Schimassek M., Schimp M., Schluter F., Schmidt D., Scholten O., Schoorlemmer H., Schovanek P., Schroder F.G., Schulte J., Schulz T., Sciutto S.J., Scornavacche M., Segreto A., Sehgal S., Shellard R.C., Sigl G., Silli G., Sima O., Smau R., Smida R., Sommers P., Soriano J.F., Squartini R., Stadelmaier M., Stanca D., Stanic S., Stasielak J., Stassi P., Streich A., Suarez-Duran M., Sudholz T., Suomij rvi T., Supanitsky A.D., Szadkowski Z., Tapia A., Taricco C., Timmermans C., Tkachenko O., Tobiska P., Todero peixoto C.J., Tome B., Torr s Z., Travaini A., Travnicek P., Trimarelli C., Tueros M., Ulrich R., Unger M., Vaclavek L., Vacula M., Valdes galicia J.F., Valore L., Varela E., Vasquez-Ramirez A., Veberic D., Ventura C., Vergara quispe I.D., Verzi V., Vicha J., Vink J., Vorobiov S., Wahlberg H., Watanabe C., Watson A.A., Weindl A., Wiencke L., Wilczynski H., Wittkowski D., Wundheiler B., Yushkov A., Zapparrata O., Zas E., Zavrtanik D., Zavrtanik M., Zehrer L., Abreu, P., Aglietta, M., Albury, J. M., Allekotte, I., Almeida Cheminant, K., Almela, A., Alvarez-Mu??iz, J., Alves Batista, R., Anastasi, G. A., Anchordoqui, L., Andrada, B., Andringa, S., Aramo, C., Ara??jo Ferreira, P. R., Arnone, E., Arteaga Vel??zquez, J. C., Asorey, H., Assis, P., Avila, G., Badescu, A. M., Bakalova, A., Balaceanu, A., Barbato, F., Bellido, J. A., Berat, C., Bertaina, M. E., Bertou, X., Bhatta, G., Biermann, P. L., Binet, V., Bismark, K., Bister, T., Biteau, J., Blazek, J., Bleve, C., Bl??mer, J., Boh????ov??, M., Boncioli, D., Bonifazi, C., Bonneau Arbeletche, L., Borodai, N., Botti, A. M., Brack, J., Bretz, T., Brichetto Orchera, P. G., Briechle, F. L., Buchholz, P., Bueno, A., Buitink, S., Buscemi, M., B??sken, M., Caballero-Mora, K. S., Caccianiga, L., Canfora, F., Caracas, I., Caruso, R., Castellina, A., Catalani, F., Cataldi, G., Cazon, L., Cerda, M., Chinellato, J. A., Chudoba, J., Chytka, L., Clay, R. W., Cobos Cerutti, A. C., Colalillo, R., Coleman, A., Coluccia, M. R., Concei????o, R., Condorelli, A., Consolati, G., Contreras, F., Convenga, F., Correia dos Santos, D., Covault, C. E., Dasso, S., Daumiller, K., Dawson, B. R., Day, J. A., de Almeida, R. M., de Jes??s, J., de Jong, S. J., de Mello Neto, J. R. T., De Mitri, I., de Oliveira, J., de Oliveira Franco, D., de Palma, F., de Souza, V., De Vito, E., Del Popolo, A., del R??o, M., Deligny, O., Deval, L., di Matteo, A., Dobre, M., Dobrigkeit, C., D'Olivo, J. C., Domingues Mendes, L. M., dos Anjos, R. C., Dova, M. T., Ebr, J., Engel, R., Epicoco, I., Erdmann, M., Escobar, C. O., Etchegoyen, A., Falcke, H., Farmer, J., Farrar, G., Fauth, A. C., Fazzini, N., Feldbusch, F., Fenu, F., Fick, B., Figueira, J. M., Filip??i??, A., Fitoussi, T., Fodran, T., Fujii, T., Fuster, A., Galea, C., Galelli, C., Garc??a, B., Garcia Vegas, A. L., Gemmeke, H., Gesualdi, F., Gherghel-Lascu, A., Ghia, P. L., Giaccari, U., Giammarchi, M., Glombitza, J., Gobbi, F., Gollan, F., Golup, G., G??mez Berisso, M., G??mez Vitale, P. F., Gongora, J. P., Gonz??lez, J. M., Gonz??lez, N., Goos, I., G??ra, D., Gorgi, A., Gottowik, M., Grubb, T. D., Guarino, F., Guedes, G. P., Guido, E., Hahn, S., Hamal, P., Hampel, M. R., Hansen, P., Harari, D., Harvey, V. M., Haungs, A., Hebbeker, T., Heck, D., Hill, G. C., Hojvat, C., H??randel, J. R., Horvath, P., Hrabovsk??, M., Huege, T., Insolia, A., Isar, P. G., Janecek, P., Johnsen, J. A., Jurysek, J., K????p??, A., Kampert, K. H., Karastathis, N., Keilhauer, B., Khakurdikar, A., Kizakke Covilakam, V. V., Klages, H. O., Kleifges, M., Kleinfeller, J., Knapp, F., Kunka, N., Lago, B. L., Lang, R. G., Langner, N., Leigui de Oliveira, M. A., Lenok, V., Letessier-Selvon, A., Lhenry-Yvon, I., Lo Presti, D., Lopes, L., L??pez, R., Lu, L., Luce, Q., Lundquist, J. P., Machado Payeras, A., Mancarella, G., Mandat, D., Manning, B. C., Manshanden, J., Mantsch, P., Marafico, S., Mariani, F. M., Mariazzi, A. G., Mari??, I. C., Marsella, G., Martello, D., Martinelli, S., Mart??nez Bravo, O., Mastrodicasa, M., Mathes, H. J., Matthews, J., Matthiae, G., Mayotte, E., Mayotte, S., Mazur, P. O., Medina-Tanco, G., Melo, D., Menshikov, A., Michal, S., Micheletti, M. I., Miramonti, L., Mollerach, S., Montanet, F., Morejon, L., Morello, C., Mostaf??, M., M??ller, A. L., Muller, M. A., Mulrey, K., Mussa, R., Muzio, M., Namasaka, W. M., Nasr-Esfahani, A., Nellen, L., Nicora, G., Niculescu-Oglinzanu, M., Niechciol, M., Nitz, D., Nosek, D., Novotny, V., No??ka, L., Nucita, A., N????ez, L. A., Oliveira, C., Palatka, M., Pallotta, J., Papenbreer, P., Parente, G., Parra, A., Pawlowsky, J., Pech, M., P??kala, J., Pelayo, R., Pe??a-Rodriguez, J., Pereira Martins, E. E., Perez Armand, J., P??rez Bertolli, C., Perlin, M., Perrone, L., Petrera, S., Petrucci, C., Pierog, T., Pimenta, M., Pirronello, V., Platino, M., Pont, B., Pothast, M., Privitera, P., Prouza, M., Puyleart, A., Querchfeld, S., Rautenberg, J., Ravignani, D., Reininghaus, M., Ridky, J., Riehn, F., Risse, M., Rizi, V., Rodrigues de Carvalho, W., Rodriguez Rojo, J., Roncoroni, M. J., Rossoni, S., Roth, M., Roulet, E., Rovero, A. C., Ruehl, P., Saftoiu, A., Saharan, M., Salamida, F., Salazar, H., Salina, G., Sanabria Gomez, J. D., S??nchez, F., Santos, E. M., Santos, E., Sarazin, F., Sarmento, R., Sarmiento-Cano, C., Sato, R., Savina, P., Sch??fer, C. M., Scherini, V., Schieler, H., Schimassek, M., Schimp, M., Schl??ter, F., Schmidt, D., Scholten, O., Schoorlemmer, H., Schov??nek, P., Schr??der, F. G., Schulte, J., Schulz, T., Sciutto, S. J., Scornavacche, M., Segreto, A., Sehgal, S., Shellard, R. C., Sigl, G., Silli, G., Sima, O., Smau, R., m??da, R., Sommers, P., Soriano, J. F., Squartini, R., Stadelmaier, M., Stanca, D., Stani??, S., Stasielak, J., Stassi, P., Streich, A., Su??rez-Dur??n, M., Sudholz, T., Suomij??rvi, T., Supanitsky, A. D., Szadkowski, Z., Tapia, A., Taricco, C., Timmermans, C., Tkachenko, O., Tobiska, P., Todero Peixoto, C. J., Tom??, B., Torr??s, Z., Travaini, A., Travnicek, P., Trimarelli, C., Tueros, M., Ulrich, R., Unger, M., Vaclavek, L., Vacula, M., Vald??s Galicia, J. F., Valore, L., Varela, E., V??squez-Ram??rez, A., Veberi??, D., Ventura, C., Vergara Quispe, I. D., Verzi, V., Vicha, J., Vink, J., Vorobiov, S., Wahlberg, H., Watanabe, C., Watson, A. A., Weindl, A., Wiencke, L., Wilczy??ski, H., Wittkowski, D., Wundheiler, B., Yushkov, A., Zapparrata, O., Zas, E., Zavrtanik, D., Zavrtanik, M., Zehrer, L., Almeida cheminant, K., Alvarez-Muniz, J., Alves batista, R., Araujo ferreira, P. R., Arteaga velazquez, J. C., Blumer, J., Bohacova, M., Bonneau arbeletche, L., Brichetto orchera, P. G., Busken, M., Cobos cerutti, A. C., Concei o, R., Correia dos santos, D., De almeida, R. M., De jesus, J., De jong, S. J., De mello neto, J. R. T., De mitri, I., De oliveira, J., De oliveira franco, D., De palma, F., De souza, V., De vito, E., Del popolo, A., Del rio, M., Di matteo, A., Domingues mendes, L. M., Dos anjos, R. C., Filipcic, A., Garcia, B., Garcia vegas, A. L., Gomez berisso, M., Gomez vitale, P. F., Gonzalez, J. M., Gonzalez, N., Gora, D., Horandel, J. R., Hrabovsky, M., Kp, A., Kizakke covilakam, V. V., Leigui de oliveira, M. A., Lo presti, D., Lopez, R., Machado payeras, A., Maris, I. C., Martinez bravo, O., Mostafa, M., Muller, A. L., Nozka, L., Nunez, L. A., Pkala, J., Pena-Rodriguez, J., Pereira martins, E. E., Perez armand, J., Perez bertolli, C., Rodrigues de carvalho, W., Rodriguez rojo, J., Sanabria gomez, J. D., Sanchez, F., Sch fer, C. M., Schluter, F., Schovanek, P., Schroder, F. G., Smida, R., Stanic, S., Suarez-Duran, M., Suomij rvi, T., Todero peixoto, C. J., Tome, B., Torr s, Z., Valdes galicia, J. F., Vasquez-Ramirez, A., Veberic, D., Vergara quispe, I. D., and Wilczynski, H.
- Subjects
interaction [cosmic radiation] ,mass spectrum [cosmic radiation] ,dispersion relation ,Astronomy ,Astrophysics::High Energy Astrophysical Phenomena ,energy spectrum ,cosmic ray experiment ,FOS: Physical sciences ,ultra high energy cosmic rays ,cosmic radiation: interaction ,invariance: Lorentz ,01 natural sciences ,UHE ,ultra high energy cosmic ray ,energy: threshold ,Fundamental physics, gravitational waves, LISA, Tests of general relativity ,Cosmic ray experiments ,0103 physical sciences ,propagation ,ddc:530 ,physics of the early universe ,High Energy Physics ,Lorentz [invariance] ,010303 astronomy & astrophysics ,photon: flux ,flux [photon] ,Lorentz [violation] ,High Energy Astrophysical Phenomena (astro-ph.HE) ,astro-ph.HE ,energy: high ,010308 nuclear & particles physics ,cosmic radiation: mass spectrum ,cosmic ray experiments ,Settore FIS/01 - Fisica Sperimentale ,Astronomy and Astrophysics ,ASTROFÍSICA ,Ultra-high energy cosmic rays ,threshold [energy] ,violation: Lorentz ,Auger ,observatory ,electromagnetic ,kinematics ,Experimental High Energy Physics ,high [energy] ,Astrophysics - High Energy Astrophysical Phenomena ,Physics of the early universe - Abstract
The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargüe. We are very grateful to the following agencies and organizations for financial support: Argentina — Comisión Nacional de Energía Atómica; Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Gobierno de la Provincia de Mendoza; Municipalidad de Malargüe; NDM Holdings and Valle Las Leñas; in gratitude for their continuing cooperation over land access; Australia — the Australian Research Council; Belgium — Fonds de la Recherche Scientifique (FNRS); Research Foundation Flanders (FWO); Brazil — Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Financiadora de Estudos e Projetos (FINEP); Fundação de Amparo à Pesquisa do Estado de Rio de Janeiro (FAPERJ); São Paulo Research Foundation (FAPESP) Grants No. 2019/10151-2, No. 2010/07359-6 and No. 1999/05404-3; Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC); Czech Republic — Grant No. MSMT CR LTT18004, LM2015038, LM2018102, CZ.02.1.01/0.0/0.0/16_013/0001402, CZ.02.1.01/0.0/0.0/18_046/0016010 and CZ.02.1.01/0.0/0.0/17_049/0008422; France — Centre de Calcul IN2P3/CNRS; Centre National de la Recherche Scientifique (CNRS); Conseil Régional Ile-de-France; Département Physique Nucléaire et Corpusculaire (PNC-IN2P3/CNRS); Département Sciences de l’Univers (SDU-INSU/CNRS); Institut Lagrange de Paris (ILP) Grant No. LABEX ANR-10-LABX-63 within the Investissements d’Avenir Programme Grant No. ANR-11-IDEX-0004-02; Germany — Bundesministerium für Bildung und Forschung (BMBF); Deutsche Forschungsgemeinschaft (DFG); Finanzministerium Baden-Württemberg; Helmholtz Alliance for Astroparticle Physics (HAP); Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF); Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen; Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-Württemberg; Italy — Istituto Nazionale di Fisica Nucleare (INFN); Istituto Nazionale di Astrofisica (INAF); Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR); CETEMPS Center of Excellence; Ministero degli Affari Esteri (MAE); México — Consejo Nacional de Ciencia y Tecnología (CONACYT) No. 167733; Universidad Nacional Autónoma de México (UNAM); PAPIIT DGAPA-UNAM; The Netherlands — Ministry of Education, Culture and Science; Netherlands Organisation for Scientific Research (NWO); Dutch national e-infrastructure with the support of SURF Cooperative; Poland — Ministry of Education and Science, grant No. DIR/WK/2018/11; National Science Centre, Grants No. 2016/22/M/ST9/00198, 2016/23/B/ST9/01635, and 2020/39/B/ST9/01398; Portugal — Portuguese national funds and FEDER funds within Programa Operacional Factores de Competitividade through Fundação para a Ciência e a Tecnologia (COMPETE); Romania — Ministry of Research, Innovation and Digitization, CNCS/CCCDI — UEFISCDI, projects PN19150201/16N/2019, PN1906010, TE128 and PED289, within PNCDI III; Slovenia — Slovenian Research Agency, grants P1-0031, P1-0385, I0-0033, N1-0111; Spain — Ministerio de Economía, Industria y Competitividad (FPA2017-85114-P and PID2019-104676GB-C32), Xunta de Galicia (ED431C 2017/07), Junta de Andalucía (SOMM17/6104/UGR, P18-FR-4314) Feder Funds, RENATA Red Nacional Temática de Astropartículas (FPA2015-68783-REDT) and María de Maeztu Unit of Excellence (MDM-2016-0692); U.S.A. — Department of Energy, Contracts No. DE-AC02-07CH11359, No. DE-FR02-04ER41300, No. DE-FG02-99ER41107 and No. DE-SC0011689; National Science Foundation, Grant No. 0450696; The Grainger Foundation; Marie Curie-IRSES/EPLANET; European Particle Physics Latin American Network; and UNESCO., Lorentz invariance violation (LIV) is often described by dispersion relations of the form E i2 = m i2+p i2+δi,n E 2+n with delta different based on particle type i, with energy E, momentum p and rest mass m. Kinematics and energy thresholds of interactions are modified once the LIV terms become comparable to the squared masses of the particles involved. Thus, the strongest constraints on the LIV coefficients δi,n tend to come from the highest energies. At sufficiently high energies, photons produced by cosmic ray interactions as they propagate through the Universe could be subluminal and unattenuated over cosmological distances. Cosmic ray interactions can also be modified and lead to detectable fingerprints in the energy spectrum and mass composition observed on Earth. The data collected at the Pierre Auger Observatory are therefore possibly sensitive to both the electromagnetic and hadronic sectors of LIV. In this article, we explore these two sectors by comparing the energy spectrum and the composition of cosmic rays and the upper limits on the photon flux from the Pierre Auger Observatory with simulations including LIV. Constraints on LIV parameters depend strongly on the mass composition of cosmic rays at the highest energies. For the electromagnetic sector, while no constraints can be obtained in the absence of protons beyond 1019 eV, we obtain δγ,0 > -10-21, δγ,1 > -10-40 eV-1 and δγ,2 > -10-58 eV-2 in the case of a subdominant proton component up to 1020 eV. For the hadronic sector, we study the best description of the data as a function of LIV coefficients and we derive constraints in the hadronic sector such as δhad,0 < 10-19, δhad,1 < 10-38 eV-1 and δhad,2 < 10-57 eV-2 at 5σ CL., Argentina — Comisión Nacional de Energía Atómica, Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Gobierno de la Provincia de Mendoza, Municipalidad de Malargüe, NDM Holdings and Valle Las Leñas, Australia — the Australian Research Council, Belgium — Fonds de la Recherche Scientifique (FNRS), Research Foundation Flanders (FWO), Brazil — Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do Estado de Rio de Janeiro (FAPERJ), São Paulo Research Foundation (FAPESP) Grants No. 2019/10151-2, No. 2010/07359-6 and No. 1999/05404-3, Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC), Czech Republic — Grant No. MSMT CR LTT18004, LM2015038, LM2018102, CZ.02.1.01/0.0/0.0/16_013/0001402, CZ.02.1.01/0.0/0.0/18_046/0016010 and CZ.02.1.01/0.0/0.0/17_049/0008422, France — Centre de Calcul IN2P3/CNRS, Centre National de la Recherche Scientifique (CNRS), Conseil Régional Ile-de-France; Département Physique Nucléaire et Corpusculaire (PNC-IN2P3/CNRS), Département Sciences de l’Univers (SDU-INSU/CNRS), Institut Lagrange de Paris (ILP) Grant No. LABEX ANR-10-LABX-63- Investissements d’Avenir Programme Grant No. ANR-11-IDEX-0004-02, Germany — Bundesministerium für Bildung und Forschung (BMBF)Germany, Deutsche Forschungsgemeinschaft (DFG), Finanzministerium Baden-Württemberg, Helmholtz Alliance for Astroparticle Physics (HAP), Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF), Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen, Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-Württemberg, Italy — Istituto Nazionale di Fisica Nucleare (INFN), Istituto Nazionale di Astrofisica (INAF), Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR), CETEMPS Center of Excellence, Ministero degli Affari Esteri (MAE), México — Consejo Nacional de Ciencia y Tecnología (CONACYT) No. 167733, Universidad Nacional Autónoma de México (UNAM), PAPIIT DGAPA-UNAM, The Netherlands — Ministry of Education, Culture and Science, Netherlands Organisation for Scientific Research (NWO), Dutch national e-infrastructure with the support of SURF Cooperative; Poland — Ministry of Education and Science, grant No. DIR/WK/2018/11, National Science Centre, Grants No. 2016/22/M/ST9/00198, 2016/23/B/ST9/01635, and 2020/39/B/ST9/01398, Portugal — Portuguese national funds and FEDER funds within Programa Operacional Factores de Competitividade through Fundação para a Ciência e a Tecnologia (COMPETE), Romania — Ministry of Research, Innovation and Digitization, CNCS/CCCDI — UEFISCDI, projects PN19150201/16N/2019, PN1906010, TE128 and PED289, within PNCDI III, Slovenia — Slovenian Research Agency, grants P1-0031, P1-0385, I0-0033, N1-0111, Spain — Ministerio de Economía, Industria y Competitividad (FPA2017-85114-P and PID2019-104676GB-C32), Xunta de Galicia (ED431C 2017/07), Junta de Andalucía (SOMM17/6104/UGR, P18-FR-4314), Feder Funds, RENATA Red Nacional Temática de Astropartículas (FPA2015-68783-REDT), María de Maeztu Unit of Excellence (MDM-2016-0692), U.S.A. — Department of Energy, Contracts No. DE-AC02-07CH11359, No. DE-FR02-04ER41300, No. DE-FG02-99ER41107 and No. DE-SC0011689, National Science Foundation, Grant No. 0450696, The Grainger Foundation, Marie Curie-IRSES/EPLANET, European Particle Physics Latin American Network, UNESCO
- Published
- 2022
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