Search

The problem of space flights safety arose with the beginning of the first launches of artificial Earth satellites. With expansion of the boundaries of space flights, the area of outer space that must be controlled to ensure flight safety is significantly increasing. In this study, we consider the possibility of capturing space objects into near-planetary space and further movement of these objects. Such statistical analysis is very important when planning the long-term flights. The objects of our research are both: the particles that came from deep space and the evolving asteroids of the Main asteroid belt. A special attention is paid to the evolution of the Griqua family of asteroids, which belong to the main asteroid belt, and move in orbital resonance with Jupiter.

Atmospheric mass density (AMD) plays a vital role in the drag calculation for space objects in low Earth orbit (LEO). Many empirical AMD models have been developed and used for orbit prediction and...

The 25Mg(p, γ )26Al reaction plays an important role in the study of cosmic 1.809 MeV γ -ray as a signature of ongoing nucleosynthesis in the Galaxy. At astrophysical temperature around 0.1 GK, the 25Mg(p, γ )26Al reaction rates are dominated by the 92 keV resonance capture process. We report a precise measurement of the 92 keV 25Mg(p, γ )26Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment (JUNA) facility in the China Jinping Underground Laboratory (CJPL). The resonance strength and ground state feeding factor are determined to be 3.8 ± 0.3 ×10−10 eV and 0.66 ± 0.04 , respectively. The results are in agreement with those reported in the previous direct underground measurement within uncertainty, but with significantly reduced uncertainties. Consequently, we recommend new 25Mg(p, γ )26Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK. The new results indicate higher production rates of 26gAl and the cosmic 1.809 MeV γ -rays. The implication of the new rates for the understanding of other astrophysical situations is also discussed.

This paper introduces three cosmic expansion models with constant, decelerating and accelerating speed of expansion respectively. Then characters of these cosmic expansion models are compared. Based on these cosmic expansion models, the thresholds of observable universe are calculated via simulations, where the earliest observable cosmic radius R(tearliest) is always 0.368R (R is cosmic radius at current universe time) for any cosmic expansion models.

Satellite measurements of the atmosphere by remote sensing techniques are becoming the trend for atmospheric probing. The problem is that such measurements are usually not continuous in time series for given Earth locations. This article presents a neural network-based method for time series modeling of the atmospheric refractivity in 3-D space using radio occultation measurements from the COSMIC mission. The method offers an opportunity to obtain continuous refractivity values in time series for any given Earth location, even if there are no measurements. Time series inputs of year, day of year, and hour of day are used to train the 3-D space measurements of refractivity from both COSMIC-1 and COSMIC-2 missions. The data cover periods from April 2006 to September 2020, and the data for the Nigerian region (and from altitudes 0.1 to 39.9 km) are illustrated. The effectiveness of solar activity indicator [sunspot number (SSN)], as an input for the neural network process, is investigated. The result shows that the SSN was an insignificant input for improving the prediction accuracy of the model. A comparison of the model predictions and the COSMIC measurements shows that there is very good correlation (correlation coefficients are approximately 1.0) between the model predictions and the COSMIC measurements. Typical root-mean-square errors between the model predictions and the COSMIC measurements are about 7.3 N-units on ground, 0.6 N-units at 20 km, and 0.3 N-units at 40 km. The model predictions are demonstrated to vary (in time and space) in patterns that agree with physical measurements of refractivity.

Covariance matrices are among the most difficult pieces of end-to-end cosmological analyses. In principle, for two-point functions, each component involves a four-point function, and the resulting covariance often has hundreds of thousands of elements. We investigate various compression mechanisms capable of vastly reducing the size of the covariance matrix in the context of cosmic shear statistics. This helps identify which of its parts are most crucial to parameter estimation. We start with simple compression methods, by isolating and "removing" 200 modes associated with the lowest eigenvalues, then those with the lowest signal-to-noise ratio, before moving on to more sophisticated schemes like compression at the tomographic level and, finally, with the Massively Optimized Parameter Estimation and Data compression (MOPED). We find that, while most of these approaches prove useful for a few parameters of interest, like $\Omega_m$, the simplest yield a loss of constraining power on the intrinsic alignment (IA) parameters as well as $S_8$. For the case considered -- cosmic shear from the first year of data from the Dark Energy Survey -- only MOPED was able to replicate the original constraints in the 16-parameter space. Finally, we apply a tolerance test to the elements of the compressed covariance matrix obtained with MOPED and confirm that the IA parameter $A_{\mathrm{IA}}$ is the most susceptible to inaccuracies in the covariance matrix., Comment: 13 pages, 12 figures, 1 table. V2 reflects version accepted for publication in PRD

In the Big Bang Theory and the Black Hole Theory, the existing laws of physics all fail at the singularity, and the singularity has become a blind spot in the existing scientific theories. In the axioms system of Cosmic continuum, the universe was not created by an instantaneous explosion, but by the continuous eruption of singularities. As long as the singularity is still erupting, the total amount of the universe will continue to increase. The so-called dark energy is actually the gravitational field energy erupted by the singularity. The expansion force of dark energy is generated by the outward eruption of singularity. The cosmic system collapse into a Schwarzschild black hole under the action of a strong gravitational field, and the Planck spheres at the center of the black hole continues to collapse into dark mass bodies, forming dark celestial body and singularity. The Schwarzschild radius is the upper limit of a black hole, and the Planck sphere is the lower limit of a black hole. The singularity is the conversion point between the old and new cosmic systems. The singularity erupts the Planck spheres under the action of a strong gravitational field, and the Planck spheres expands outward to form a new cosmic system. The Planck sphere is both the end of the old cosmic system and the starting point of the new cosmic system. The black hole collapse and the singularity eruption are mirror images of each other.

In this article, I’ll outline the phenomenon of ‘cosmic wellness’ which is now visible across on- and offline spaces that promote health and well-being products and practices to women. Cosmic wellness is a broad constellation of media, discourse, imagery, materials and foods (including crystals, dust and herbs) produced primarily by white, wealthy women. On the one hand, cosmic wellness can be read as a digital food culture that offers healthy and potentially necessary responses to fiercely neoliberal modes of working and living. But conversely, it is framed as the newest example of narcissistic self-absorption and, more seriously, as unhealthy and dangerous. Cosmic wellness is founded on various beliefs, including the moral necessity of pursuing the optimisation of self and the power of markets to provide the ingredients, tools and practices to achieve it. It is connected to histories that chart the incorporation of New Age health and well-being practices into ‘mainstream’ forms of lifestyle production and consumption and the simultaneous derision of these practices, especially when used and promoted by women. But there is also something new about cosmic wellness, especially as it is visible online on platforms such as Instagram. In the article, I outline the key features of cosmic wellness and analyse its contemporary cultural purchase, using theories of digital food cultures, spiritual production and consumption, postfeminism and critical whiteness studies. The article then conducts empirical analysis of a series of Instagram posts from one prominent space in which cosmic wellness currently circulates: Gwyneth Paltrow’s lifestyle and wellness business Goop.

Cosmic Christology, including deep incarnation, provides an ethical-theological framework for confronting environmental crisis. It criticizes ‘history’ as arrogantly anthropocentric and proposes a paradigm shift from Christ the Saviour of history to the Christ of the cosmos. Whereas I recognize these strengths for protecting nature, I argue that in its universal pretension Christ too often becomes an abstract reality and loses material grounding for social justice. In its eagerness to supplant the Christ the Saviour of history, cosmic Christology risks stripping humanity from those deemed ‘non-persons’ and inadvertently reinforces the status of the oppressed as subalterns. Likewise, by de-legitimizing history, and by putting exploited nature and the oppressed as equivalents, struggles by subalterns for recognition and justice are diminished. To avoid this, I argue that the salvation of nature passes through the salvation of history. Only the Christ the Saviour of history can be the cosmic Christ.

New results of ionospheric Total Electron Content (TEC) measurements obtained from a newly installed low-cost multi-frequency Global Navigation Satellite System (GNSS) U-BLOX receiver at Abuja-Nigeria (Geographic: 8.99° N, 7.38° E; Geomagnetic: 1.6° S) is presented. The paper motivates the use of the U-BLOX receiver for TEC studies in the African equatorial region. Data obtained for the periods of July-August and November-December 2020 are used. TEC data from the U-BLOX are compared with TEC obtained from a nearby high-cost GNSS receiver, and with COSMIC – RO (Constellation Observing System for Meteorology Ionosphere and Climate – Radio Occultation) TEC measurements. Corresponding TEC values from the AfriTEC and NeQuick ionospheric models are also presented. The results show an excellent level of agreement between the U-BLOX and high-cost GNSS receiver measurements. The COSMIC values were typically less than the U-BLOX and high-cost receiver values, and this is mainly attributed to the difference in TEC integration heights used for the two systems. The correlation coefficients between the U-BLOX values and values from the other four datasets are mostly greater than 0.9. The root-mean-square differences (RMSDs) between the U-BLOX and high-cost receiver values are about 2 TECU and less. The RMSDs between the U-BLOX values and values from each of the AfriTEC and NeQuick models are less than 5 TECU. The values are comparable and even lower than values computed in previous research that used TEC from high-cost receivers. There is also consistent and significant agreement between 30-second ROT values computed from both the low-cost and high-cost receivers. These results summarily indicate that the U-BLOX is a good candidate for TEC studies in the region, just like the high-cost receivers.

Galactic cosmic rays (GCRs) inside the heliosphere are affected by magnetic turbulence and Solar wind disturbances which result in the so-called solar modulation effect. To investigate this phenomenon, we have performed a data-driven analysis of the temporal dependence of the GCR flux over the solar cycle. With a global statistical inference of GCR data collected in space by AMS-02, PAMELA, and CRIS on monthly basis, we have determined the dependence of the GCR diffusion parameters upon time and rigidity. In this conference, we present our results for GCR protons and nuclei, we discuss their interpretation in terms of basic processes of particle transport and their relations with the dynamics of the heliospheric plasma., 8 pages, 3 figures, proceedings of ICRC-2021 conference

Analyses of large-scale cancer sequencing data have revealed that mutagenic processes can create distinctive patterns of base substitutions, called mutational signatures. Interestingly, mutational patterns resembling some of these signatures can also be observed in normal cells. To determine whether similar patterns exist more generally, we analyzed large data sets of genetic variation, including mutations from 7 model species and single nucleotide polymorphisms in 42 species, totaling >1.9 billion variants. We found that base substitution patterns for most species closely match single base substitution (SBS) mutational signature 5 in the Catalog of Somatic Mutations in Cancer (COSMIC) database. SBS5 is ubiquitous in cancers and also present in normal human cells, suggesting that similar patterns of genetic variation across so many species are likely due to conserved biochemistry. We investigated the mechanistic origins of the SBS5-like mutational pattern in Saccharomyces cerevisiae, and show that translesion DNA synthesis and sugar metabolism are directly linked to this form of mutagenesis. We propose that conserved metabolic processes in cells are coupled to continuous generation of genetic variants, which can be acted upon by selection to drive the evolution of biological entities.

The chemical evolution of the Universe and several phases of the stellar life are regulated by minute nuclear reactions. The key point for each of these reactions is the value of cross sections at the energies at which they take place in stellar environments. Direct cross-section measurements are mainly hampered by the very low counting rate and by cosmic background, nevertheless they have become possible by combining the best experimental techniques with the cosmic silence of an underground laboratory. In the nineties the LUNA (Laboratory for Underground Nuclear Astrophysics) collaboration opened the era of underground nuclear astrophysics installing first a home-made 50 kV and later on, a second 400 kV accelerator under the Gran Sasso mountain in Italy: in 25 years of experimental activity, important reactions responsible for hydrogen burning could have been studied down to the relevant energies thanks to the high current proton and helium beams provided by the machines. The interest to the next and warmer stages of star evolution (i.e. post main sequence, helium and carbon burning) drove a new project based on an ion accelerator in the MV range called LUNA-MV, able to deliver proton, helium and carbon beams. The present contribution is aimed to discuss the state-of-the-art for some selected key processes of post main sequence stellar phases: the 12Cag and the 12C+12C fundamental for helium and carbon burning phases, and 13Can and 22Neag that are relevant to the synthesis of heavy elements in AGB stars. The perspectives opened by an underground MV-facility will be highlighted., 18 pages, 13 figures

We put forward a pressure-parametric model to study the tiny deviation from cosmological constant(CC) behavior of the dark sector accelerating the expansion of the Universe. Data from cosmic microwave background (CMB) anisotropies, baryonic acoustic oscillations (BAO), Type Ia supernovae (SN Ia) observation are applied to constrict the model parameters. The constraint results show that such model suffers with $H_0$ tension as well. To realize this model more physically, we reconstruct it with the quintessence and phantom scalar fields, and find out that although the model predicts a quintessence-induced acceleration of the Universe at past and present, at some moment of the future, dark energy's density have a disposition to increase., 14 pages, 10 figures, 1 table, accepted by Modern Physics Letters A (Vol. 35, No. 25, 2050209 (2020))

After updating the status of the measurements of the cosmic neutrino flux by the IceCube experiment, we summarize the observations of the first identified source of cosmic rays and speculate on the connection between the two observations.

It is important to map the large-scale matter distribution in the local Universe for cosmological studies, such as the tracing of the large-scale peculiar velocity flow, the characterisation of the environment for different astronomical objects, and for precision measurements of cosmological parameters. We used X-ray luminous clusters to map this matter distribution and find that about 51% of the groups and clusters are members of superclusters which occupy only a few percent of the volume. In this paper we provide a detailed description of these large-scale structures. With a friends-to-friends algorithm, we find eight superclusters with a cluster overdensity ratio of at least two with five or more galaxy group and cluster members in the cosmic volume out to z = 0.03. The four most prominent ones are the Perseus-Pisces, the Centaurus, the Coma, and the Hercules supercluster, with lengths from about 40 to over 100 Mpc and estimated masses of 0.6 - 2.2 10^16 Msun. The largest of these structures is the Perseus-Pisces supercluster. The four smaller superclusters include the Local and the Abell 400 supercluster and two superclusters in the constellations Sagittarius and Lacerta. We provide detailed maps, member catalogues, and physical descriptions of the eight superclusters. By constructing superclusters with a range of cluster sub-samples with different lower X-ray luminosity limits, we show that the main structures are always reliably recovered., Comment: Published in Astronomy and Astrophysics, 31 pages, 28 figures

The emergence of a highly improbable coincidence in cosmological observations speaks to a remarkably simple cosmic expansion. Compelling evidence now suggests that the Universe's gravitational horizon, coincident with the better known Hubble sphere, has a radius improbably equal to the distance light could have travelled since the Big Bang. The confirmation of this unexpected result would undoubtedly herald the influence of new physics, yet appears to be unavoidable after a recent demonstration that the Friedmann-Lemaitre-Robertson-Walker metric is valid only for the so-called zero active mass equation of state. As it turns out, a cosmic fluid with this property automatically produces the aforementioned equality, leaving little room for a cosmological constant. The alternative---a dynamical dark energy---would suggest an extension to the standard model of particle physics, and a serious re-evaluation of the Universe's early history., 23 pages, 9 figures, Review article accepted for publication in Modern Physics Letters A

The RELEC scientific instrumentation onboard the Vernov spacecraft launched on July 8, 2014, included the DRGE gamma-ray and electron spectrometer. This instrument incorporates a set of scintillation phoswich detectors, including four identical X-ray and gamma-ray detectors in the energy range from 10 keV to 3 MeV with a total area of $\sim$500 $cm^{2}$ directed toward the nadir, and an electron spectrometer containing three mutually orthogonal detector units with a geometry factor of $\sim$2 $cm^{2} sr$, which is also sensitive to X-rays and gamma-rays. The goal of the space experiment with the DRGE instrument was to investigate phenomena with fast temporal variability, in particular, terrestrial gamma-ray flashes (TGFs) and magnetospheric electron precipitations. However, the detectors of the DRGE instrument could record cosmic gamma-ray bursts (GRBs) and allowed one not only to perform a detailed analysis of the gamma-ray variability but also to compare the time profiles with the measurements made by other instruments of the RELEC scientific instrumentation (the detectors of optical and ultraviolet flashes, the radio-frequency and low-frequency analyzers of electromagnetic field parameters). We present the results of our observations of cosmic GRB 141011A and GRB 141104A, compare the parameters obtained in the GBM/Fermi and KONUSWind experiments, and estimate the redshifts and Eiso for the sources of these GRBs. The detectability of GRBs and good agreement between the independent estimates of their parameters obtained in various experiments are an important factor of the successful operation of similar detectors onboard the Lomonosov spacecraft., 19 pages, 8 figures

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Monthly Notices of the Royal Astronomical Society 510.1 (2022): 581-592 is available online at: https://academic.oup.com/mnras/article-abstract/510/1/581/6445057?redirectedFrom=fulltext, Galaxy clusters grow by accreting galaxies from the field and along filaments of the cosmic web. As galaxies are accreted they are affected by their local environment before they enter (pre-processing), and traverse the cluster potential. Observations that aim to constrain pre-processing are challenging to interpret because filaments comprise a heterogeneous range of environments including groups of galaxies embedded within them and backsplash galaxies that contain a record of their previous passage through the cluster. This motivates using modern cosmological simulations to dissect the population of galaxies found in filaments that are feeding clusters, to better understand their history, and aid the interpretation of observations. We use zoom-in simulations from The ThreeHundred project to track haloes through time and identify their environment. We establish a benchmark for galaxies in cluster infall regions that supports the reconstruction of the different modes of pre-processing. We find that up to 45 per cent of all galaxies fall into clusters via filaments (closer than 1 h-1Mpc from the filament spine). 12 per cent of these filament galaxies are long-established members of groups and between 30 and 60 per cent of filament galaxies at R200 are backsplash galaxies. This number depends on the cluster's dynamical state and sharply drops with distance. Backsplash galaxies return to clusters after deflecting widely from their entry trajectory, especially in relaxed clusters. They do not have a preferential location with respect to filaments and cannot collapse to form filaments. The remaining pristine galaxies (∼30-60 per cent) are environmentally affected by cosmic filaments alone

The comparison of redshift-distance relationship for high and low-redshift supernovae revealed the surprising transition of the Universe’s expansion from deceleration to acceleration. As compared to local supernovae, remote supernovae appear 10% to 25% dimmer as they are further away than expected. The expansion rate obtained for local supernovae is higher with low redshifts as compared to the expansion rate obtained for remote supernovae with high redshifts. Since observed redshifts in an expanding Universe provide an estimate of recession velocities, therefore, it is very disturbing to find that low recession velocities (just 1% of speed of light) indicate a faster rate of expansion (acceleration), whereas high recession velocities (60% of speed of light) indicate a slower rate of expansion (deceleration). In this paper, I unravel an undiscovered aspect that perfectly mimics cosmic acceleration. Rather than “cosmic deceleration that preceded the current epoch of cosmic acceleration”, I show in this paper, that “consecutive expansion epochs of the Universe that preceded the current epoch of cosmic expansion” were responsible for placing remote supernovae further away than expected. As a consequence of consecutive expansion, expansion began for remote structures in preceding expansion epochs before it did for local structures in the current (or more recent) expansion epoch; remote supernovae, quasars, and gamma-ray bursts are therefore not only further away than expected, but they also happen to yield a slower rate of expansion, thereby suggesting their deceleration even with “superluminal expansion”. As a result of consecutive expansion, preceding expansion epochs appear to be decelerating as compared to the expansion epoch that succeeds them. The analysis is based on the redshift-distance relationship plotted for 580 type Ia supernovae from the Supernova Cosmology Project, 7 additional high-redshift type Ia supernovae discovered through the Advanced Camera for Surveys on the Hubble Space Telescope from the Great Observatories Origins Deep Survey Treasury program, and 1 additional very high-redshift type Ia supernova discovered with Wide Field and Planetary Camera 2 on the Hubble Space Telescope. The results obtained by the High-Z Supernova Search Team through observations of type Ia supernovae have also been analysed. Studies incorporating quasars and gamma-ray bursts to determine how the expansion of the Universe has changed over time have been taken into consideration as well. The results obtained in this paper have been confirmed by plotting velocity-distance relationship, expansion rate vs. time relationship, expansion factor vs. time relationship, scale factor vs. time relationship, scale factor vs. distance relationship, distance-redshift relationship, distance modulus vs. redshift relationship, and Hubble residuals, moreover, the deceleration parameter (q0) is also found to be negative (q0 < 0).

As one of the most important dynamic processes in the middle and upper atmosphere, gravity waves (GWs) play a key role in determining the global atmospheric circulation. Gravity wave potential energy (GW Ep) is an important parameter that characterizes GW intensity, so understanding its global distribution is necessary. In this paper, a deep learning algorithm (DeepLab V3+) is used to estimate the stratospheric GW Ep. The deep learning model inputs are ERA5 reanalysis datasets and GMTED2010 terrain data. The output is the estimated GW Ep averaged over 2030 km from 60°S60°N. The GW Ep averaged over 20~30 km calculated by COSMIC radio occultation (RO) data is used as the measured value corresponding to the model output. The results showed that (1) this method can effectively estimate the zonal trend of GW Ep. However, the errors between the estimated and measured value of Ep are larger in low-latitude regions than in mid-latitude regions. The large number of convolution operations used in the deep learning model may be the main reason. Additionally, the measured Ep has errors associated with interpolation to the grid, the error tends to be amplified in low-latitude regions because the GW Ep is larger and the RO data are relatively sparse, which affects the training accuracy. (2) The estimated Ep shows seasonal variations, which are stronger in the winter hemisphere and weaker in the summer hemisphere. (3) The effect of quasi-biennial oscillation (QBO) can be clearly observed in the monthly variation in the estimated GW Ep, and its QBO amplitude may be less than that of the measured Ep.

Euclid Consortium: N. Hamaus et al., Euclid is poised to survey galaxies across a cosmological volume of unprecedented size, providing observations of more than a billion objects distributed over a third of the full sky. Approximately 20 million of these galaxies will have their spectroscopy available, allowing us to map the three-dimensional large-scale structure of the Universe in great detail. This paper investigates prospects for the detection of cosmic voids therein and the unique benefit they provide for cosmological studies. In particular, we study the imprints of dynamic (redshift-space) and geometric (Alcock–Paczynski) distortions of average void shapes and their constraining power on the growth of structure and cosmological distance ratios. To this end, we made use of the Flagship mock catalog, a state-of-the-art simulation of the data expected to be observed with Euclid. We arranged the data into four adjacent redshift bins, each of which contains about 11 000 voids and we estimated the stacked void-galaxy cross-correlation function in every bin. Fitting a linear-theory model to the data, we obtained constraints on f/b and DMH, where f is the linear growth rate of density fluctuations, b the galaxy bias, DM the comoving angular diameter distance, and H the Hubble rate. In addition, we marginalized over two nuisance parameters included in our model to account for unknown systematic effects in the analysis. With this approach, Euclid will be able to reach a relative precision of about 4% on measurements of f/b and 0.5% on DMH in each redshift bin. Better modeling or calibration of the nuisance parameters may further increase this precision to 1% and 0.4%, respectively. Our results show that the exploitation of cosmic voids in Euclid will provide competitive constraints on cosmology even as a stand-alone probe. For example, the equation-of-state parameter, w, for dark energy will be measured with a precision of about 10%, consistent with previous more approximate forecasts., NH, GP and JW are supported by the Excellence Cluster ORIGINS, which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2094 – 390783311. MA, MCC and SE are supported by the eBOSS ANR grant (under contract ANR-16-CE31-0021) of the French National Research Agency, the OCEVU LABEX (Grant No. ANR-11-LABX-0060) and the A*MIDEX project (Grant No. ANR-11-IDEX-0001-02) funded by the Investissements d’Avenir French government program, and by CNES, the French National Space Agency. AP is supported by NASA ROSES grant 12-EUCLID12-0004, and NASA grant 15-WFIRST15-0008 to the Nancy Grace Roman Space Telescope Science Investigation Team “Cosmology with the High Latitude Survey”. GL is supported by the ANR BIG4 project, grant ANR-16-CE23-0002 of the French Agence Nationale de la Recherche. PN is funded by the Centre National d’Etudes Spatiales (CNES). We acknowledge use of the Python libraries NumPy (Harris et al. 2020), SciPy (Virtanen et al. 2020), Matplotlib (Hunter 2007), Astropy (Astropy Collaboration 2013, 2018), emcee (Foreman-Mackey et al. 2019), GetDist (Lewis 2019), healpy (Górski et al. 2005; Zonca et al. 2019), and PyAbel (Hickstein et al. 2019). This work has made use of CosmoHub (Carretero et al. 2017; Tallada et al. 2020). CosmoHub has been developed by the Port d’Informació Científica (PIC), maintained through a collaboration of the Institut de Física d’Altes Energies (IFAE) and the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) and the Institute of Space Sciences (CSIC & IEEC), and was partially funded by the “Plan Estatal de Investigación Científica y Técnica y de Innovación” program of the Spanish government. The Euclid Consortium acknowledges the European Space Agency and a number of agencies and institutes that have supported the development of Euclid, in particular the Academy of Finland, the Agenzia Spaziale Italiana, the Belgian Science Policy, the Canadian Euclid Consortium, the Centre National d’Etudes Spatiales, the Deutsches Zentrum für Luft- und Raumfahrt, the Danish Space Research Institute, the Fundação para a Ciência e a Tecnologia, the Ministerio de Economia y Competitividad, the National Aeronautics and Space Administration, the Netherlandse Onderzoekschool Voor Astronomie, the Norwegian Space Agency, the Romanian Space Agency, the State Secretariat for Education, Research and Innovation (SERI) at the Swiss Space Office (SSO), and the United Kingdom Space Agency.

The mass composition is one of the key observables to understand the nature and origin of ultra-high energy cosmic rays.The study of hadronic interactions at energies well beyond human-made accelerators is a fundamental probe of elementary particle physics. In previous analyses, the properties of the hadronic interactions were estimated under the assumption of a certain mass composition, typically proton-dominated, and the cross sections were calculated by fitting the tail of the $X_{max}$ distribution. In such an analysis, the impact of a possible He-contamination on the cross section measurement is quoted as a systematic uncertainty. Vice versa, the cosmic-ray mass composition is typically determined using air shower simulations by assuming the validity of the considered hadronic interaction models. In this contribution, we present a fully self-consistent approach of varying the proton-proton cross sections, with the nucleus-nucleus cross sections being predicted via the Glauber theory, and making a full $X_{max}$ distribution fit to get an independent and simultaneous estimation of the interaction cross sections and cosmic-ray primary composition. We will discuss the degeneracy between mass composition and hadronic interactions and compare the sensitivity of the proposed method to one of the previous approaches.

We pursue a program to confront observations with inhomogeneous extensions of the FLRW metric. The main idea is to test the Copernican principle rather than assuming it a priori. We consider the $\Lambda$CDM model endowed with a spherical $\Lambda$LTB inhomogeneity around us, that is, we assume isotropy and test the hypothesis of homogeneity. We confront the $\Lambda$LTB model with the latest available data from CMB, BAO, type Ia supernovae, local $H_0$, cosmic chronometers, Compton y-distortion and kinetic Sunyaev-Zeldovich effect. We find that these data can constrain tightly this extra inhomogeneity, almost to the cosmic variance level: on scales $\gtrsim 100$ Mpc structures can have a small non-Copernican effective contrast of just $\delta_L \sim 0.01$. Furthermore, the constraints on the standard $\Lambda$CDM parameters are not weakened after marginalizing over the parameters that model the local structure, to which we assign ignorance priors. In other words, dropping the Copernican principle assumption does not imply worse constraints on the cosmological parameters. This positive result confirms that the present and future data can be meaningfully analyzed within the framework of inhomogeneous cosmology., Comment: 13 pages, 6 figures, 2 tables, v2 reflects version accepted for publication in MNRAS

Low-energy cosmic ray antideuterons ($

37. International Cosmic Ray Conference, ICRC 2021, Berlin, Germany, 15 Jul 2021 - 22 Jul 2021; Proceedings of Science 395, 940 (2022). doi:10.22323/1.395.0940 special issue: "37th International Cosmic Ray Conference : ICRC2021 : 12-23 July 2021 : Berlin, Germany - Online / Editorial Board: Alexander Kappes, Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany ; Bianca Keilhauer, Karlsruhe Institute of Technology, Institute for Astroparticle Physics (IAP)", Published by SISSA, Trieste

The Square Kilometre Array (SKA) is a planned radio interferometer of unprecedented scale that will revolutionize low-frequency radio astronomy when completed. In particular, one of its core science drivers is the systematic mapping of the Cosmic Dawn and Epoch of Reionization, which mark the birth of the first stars and galaxies in the Universe and their subsequent ionization of primordial intergalactic hydrogen, respectively. The SKA will offer the most sensitive view of these poorly understood epochs using the redshifted 21 cm hyperfine signal from intergalactic hydrogen. However, significant technical challenges stand in the way of realizing this scientific promise. These mainly involve the mitigation of systematics coming from astrophysical foregrounds, terrestrial radio interference, and the instrumental response. The Low Frequency Array, the Murchison Widefield Array and the Hydrogen Epoch of Reionization Array are SKA pathfinder experiments that have developed a variety of strategies for addressing these challenges, each with unique characteristics that stem largely from their different instrumental designs. We outline these various directions, highlighting key differences and synergies, and discuss how these relate to the future of low-frequency intensity mapping with the SKA. We also briefly summarize the challenges associated with modeling the 21 cm signal and discuss the methodologies being proposed for inferring constraints on astrophysical models., Comment: Version accepted to JATIS

The muonic component of air showers is sensitive to the mass and energy of the primary cosmic ray and is the most abundant component of charged particles arriving at the surface, and able to penetrate deep underground. The muon charge ratio, defined as the number of positive over negatively charged muons, is a very interesting quantity for the study of hadronic interactions at high energies and the nature of cosmic ray primaries. Furthermore, Earth's atmosphere is the development medium of cosmic air showers before they arrive at the ground. Therefore, variations in the density of the atmosphere between seasons must be studied. It is also very important to account for the zenith angular dependence of atmospheric muons, in particular for showers penetrating the atmosphere at high zenith angles. We present a study of the muon charge ratio using Monte Carlo simulations of two cosmic primaries, proton, and iron, of 100 TeV and 1 PeV energies, and with a zenith angle of 0° to 60°. The dependence on the direction of extensive air showers EAS and their radial distance appears to be very pronounced. In addition, the muon density is discussed assuming the Central European Atmosphere in June and December.

Rapid binary population synthesis codes are often used to investigate the evolution of compact-object binaries. They typically rely on analytical fits of single-star evolutionary tracks and parameterized models for interactive phases of evolution (e.g., mass-transfer on thermal timescale, determination of dynamical instability, and common envelope) that are crucial to predict the fate of binaries. These processes can be more carefully implemented in stellar structure and evolution codes such as MESA. To assess the impact of such improvements, we compare binary black hole mergers as predicted in models with the rapid binary population synthesis code COSMIC to models ran with MESA simulations through mass transfer and common-envelope treatment. We find that results significantly differ in terms of formation paths, the orbital periods and mass ratios of merging binary black holes, and consequently merger rates. While common-envelope evolution is the dominant formation channel in COSMIC, stable mass transfer dominates in our MESA models. Depending upon the black hole donor mass, and mass-transfer and common-envelope physics, at sub-solar metallicity COSMIC overproduces the number of binary black hole mergers by factors of 2--35 with a significant fraction of them having merger times orders of magnitude shorter than the binary black holes formed when using detailed MESA models. Therefore we find that some binary black hole merger rate predictions from rapid population syntheses of isolated binaries may be overestimated by factors of ~5--500. We conclude that the interpretation of gravitational-wave observations requires the use of detailed treatment of these interactive binary phases., 17 pages (13 main text), 5 figures, ApJ, in press

We present recent improvements to the search for the global Cosmic Dawn signature using the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA-SV). These improvements are both in the methodology of the experiment and the hardware of the station. An improved observing strategy along with more sophisticated temperature calibration and foreground modelling schemes have led to improved residual RMS limits. A large improvement over previous work using LWA-SV is the use of a novel achromatic beamforming technique which has been developed for LWA-SV. We present results from an observing campaign which contains 29 days of observations between March $10^{\rm{th}}$, 2021 and April $10^{\rm{th}}$ 2021. The reported residual RMS limits are 6 times above the amplitude of the potential signal reported by the Experiment to Detect the Global EoR Signature (EDGES) collaboration., Comment: 12 pages, 6 figures

In light of the statistical performance of cosmological observations, in this work we present the cosmography in f(T,B) gravity. In this scenario we found a cosmological viable standard case that allows the reduction of the degeneracy between several f(T,B) models already proposed in the literature. Furthermore, we constrain this model using Pantheon SNeIa compilation, cosmic chronometers and a newly GRB calibrated data sample. We found that with an appropriate strategy for including the cosmographic parameter, we do produce a viable cosmology with our model within f(T,B) gravity., peer-reviewed

The process of heating and reionization of the Universe at high redshifts links small-scale structures/galaxy formation and large-scale intergalactic medium (IGM) properties. Even if the first one is difficult to observe, an observation window is opening on the second one, with the promising development of current and future radio telescopes. They will permit to observe the 21 cm brightness temperature global signal and fluctuations. The need for large-scale simulations is therefore strong to understand the properties of the IGM that will be observed. However, at the same time, the urge to resolve the structures responsible for those processes is important. We introduce in this study a simulation framework of the cosmic dawn and reionization, based on hydrodynamics and radiative transfer code and a simple subgrid galaxy formation process for 1 Mpc-resolution simulations. Here, this model is calibrated on the state-of-the-art simulation CoDaII. This scheme permits us to follow consistently dark matter, hydrodynamics, and radiative transfer evolution on large scales, while the subgrid model deals with the galaxy formation scale, in particular, taking into account the different feedback on the star formation. We process the simulation to produce a simulated 21 cm signal as close as possible to the observations.

NenuFAR, the New Extension in Nancay Upgrading LOFAR, is currently in its early science phase. It is in this context that the Cosmic Filaments and Magnetism Pilot Survey is observing sources with the array as it is still under construction - with 57 (56 core, 1 distant) out of a total planned 102 (96 core, 6 distant) mini-arrays online at the time of observation - to get a first look at the low-frequency sky with NenuFAR. One of its targets is the Coma galaxy cluster: a well-known object, host of the prototype radio halo. It also hosts other features of scientific import, including a radio relic, along with a bridge of emission connecting it with the halo. It is thus a well-studied object. In this paper, we show the first confirmed NenuFAR detection of the radio halo and radio relic of the Coma cluster at 34.4 MHz, with associated intrinsic flux density estimates: we find an integrated flux value of 106.3 +- 3.5 Jy for the radio halo, and 102.0 +- 7.4 Jy for the radio relic. These are upper bound values, as they do not include point-source subtraction. We also give an explanation of the technical difficulties encountered in reducing the data, along with steps taken to resolve them. This will be helpful for other scientific projects which will aim to make use of standalone NenuFAR imaging observations in the future., Comment: 14 pages, 4 figures, special issue of the Galaxies journal

Radioactive components of the interstellar medium provide an entirely-different and new aspect to the studies of the interstellar medium. Injected from sources of nucleosynthesis, unstable nuclei decay along their trajectories. Measurements can occur through characteristic gamma rays that are emitted with the decay, or in cosmic material samples through abundances of parent and daughter isotopes as they change with decay. The dynamics and material flows within interstellar medium are thus accessible to measurement, making use of the intrinsic clock that radioactive decay provides. We describe how measurements of radioactive decay have obtained a break-through in studies of the interstellar medium, after first summarizing the characteristics of radioactivity and the sources of unstable nuclei., Comment: 16 pages, 13 figures. Contribution to Topical Collection of Astrophysics and Space Sciences about Plasma, Particles, and Photons: ISM Physics Revisited. Accepted for publication in Astrophysics and Space Science

Graphical abstract, We present interesting application of artificial intelligence for investigating effect of the COVID-19 lockdown on 3-dimensional temperature variation across Nigeria (2°–15° E, 4°–14° N), in equatorial Africa. Artificial neural networks were trained to learn time-series temperature variation patterns using radio occultation measurements of atmospheric temperature from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). Data used for training, validation and testing of the neural networks covered period prior to the lockdown. There was also an investigation into the viability of solar activity indicator (represented by the sunspot number) as an input for the process. The results indicated that including the sunspot number as an input for the training did not improve the network prediction accuracy. The trained network was then used to predict values for the lockdown period. Since the network was trained using pre-lockdown dataset, predictions from the network are regarded as expected temperatures, should there have been no lockdown. By comparing with the actual COSMIC measurements during the lockdown period, effects of the lockdown on atmospheric temperatures were deduced. In overall, the mean altitudinal temperatures rose by about 1.1 ℃ above expected values during the lockdown. An altitudinal breakdown, at 1 km resolution, reveals that the values were typically below 0.5 ℃ at most of the altitudes, but exceeded 1 ℃ at 28 and 29 km altitudes. The temperatures were also observed to drop below expected values at altitudes of 0 to 2 km, and 17 to 20 km.

In this manuscript, we investigate the patterns of the cosmological anisotropy in the spatially flat Bianchi models filled with a perfect fluid. We analyse the factor 1 + Δ R , the ratio of the Hubble parameter in the anisotropic model over its isotropic counterpart. In general, Δ R starts to deviate significantly from zero at a specific redshift z A , which depends on the type of the fluid and the value of the anisotropy magnitude. We also show that the deceleration and the jerk along the principal directions of the expansion tensor are constrained by simple algebraic equations that do not depend on the type of matter present. These characteristic patterns form a valuable framework to probe the cosmological anisotropy in the late-time universe.

Precise cosmic web classification of observed galaxies in massive spectroscopic surveys can be either highly uncertain or computationally expensive. As an alternative, we explore a fast Machine Learning-based approach to infer the underlying dark matter tidal cosmic web environment of a galaxy distribution from its $\beta$-skeleton graph. We develop and test our methodology using the cosmological magnetohydrodynamic simulation Illustris-TNG at $z=0$. We explore three different tree-based machine-learning algorithms to find that a random forest classifier can best use graph-based features to classify a galaxy as belonging to a peak, filament or sheet as defined by the T-Web classification algorithm. The best match between the galaxies and the dark matter T-Web corresponds to a density field smoothed over scales of $2$ Mpc, a threshold over the eigenvalues of the dimensionless tidal tensor of $\lambda_{\rm{th}}=0.0$ and galaxy number densities around $8\times 10^{-3}$ Mpc$^{-3}$. This methodology results on a weighted F1 score of 0.728 and a global accuracy of 74\%. More extensive tests that take into account lightcone effects and redshift space distortions (RSD) are left for future work. We make one of our highest ranking random forest models available on a public repository for future reference and reuse., Comment: ApJ accepted, 13 pages, 9 figures

The detection of the radio signal from filaments in the cosmic web is crucial to distinguish possible magnetogenesis scenarios. We review the status of the different attempts to detect the cosmic web at radio wavelengths. This is put into the context of the advanced simulations of cosmic magnetism carried out in the last few years by our {\magcow} project. While first attempts of imaging the cosmic web with the MWA and LOFAR have been encouraging and could discard some magnetogenesis models, the complexity behind such observations makes a definitive answer still uncertain. A combination of total intensity and polarimetric data at low radio frequencies that the SKA and LOFAR2.0 will achieve is key to removing the existing uncertainties related to the contribution of many possible sources of signal along deep lines of sight. This will make it possible to isolate the contribution from filaments, and expose its deep physical connection with the origin of extragalactic magnetism., Comment: 27 pages, 5 figures. Galaxies, in press

The initial metallicity of Type Ia Supernovae (SNe Ia) progenitor that is increasing with the cosmological chemical evolution will directly lead to a decrease of the 56Ni formed during the nucleosynthesis and then a varying standard candle. The variation may seriously affect our understanding of the evolving universe. In this work, we derived the relationships between 56Ni yield and metallicity in different progenitor channels. The evolution of the cosmic mean metallicity (CMM) was used to estimate the initial metallicity of progenitors. The effect of the delay times from the birth of progenitors to their explosion was also considered. The corrections of SNe Ia luminosity were estimated and the influences of the different progenitor channels and CMM evolution rates were examined. Several important cosmological parameters were updated according to the luminosity corrections.

In this paper we have studied Van-Der-Waals fluid system with the generalized EOS as as discussed in the recent works of Kremer, G.M [1, 4], Vardiashvili, G [2], Jantsch, R.C [3], Capozziello, S [5]. and are functions of energy density and time that are different for the three types of Van der Waals fluid which are one parameter model, two parameters model and three parameters model. We have studied the changes in the parameters for different cosmic phases. We have also investigated the thermodynamics and the stability conditions for these three models. Finally, we have resolved the finite time future singularity problems, Comment: 28 pages, 27 figures. Physica Scripta (2021)