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1. High-Statistics Measurement of the Cosmic-Ray Electron Spectrum with H.E.S.S

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaoui, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Collins, T., Cotter, G., Mbarubucyeye, J. Damascene, Devin, J., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Ernenwein, J. -P., Fegan, S., Feijen, K., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glicenstein, J. F., Glombitza, J., Grolleron, G., Heß, B., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Kerszberg, D., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Luashvili, A., Mackey, J., Malyshev, D., Marandon, V., Marinos, P., Marti-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Moghadam, M. O., Mohrmann, L., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, D., Pensec, U., Peron, G., Pühlhofer, G., Punch, M., Quirrenbach, A., Ravikularaman, S., Regeard, M., Reimer, A., Reimer, O., Reis, I., Ren, H., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Sharma, A., Sol, H., Spencer, S., Stawarz, L., Steinmassl, S., Steppa, C., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Tsirou, M., van Eldik, C., Vecchi, M., Venter, C., Vink, J., Wach, T., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., and Zywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Owing to their rapid cooling rate and hence loss-limited propagation distance, cosmic-ray electrons and positrons (CRe) at very high energies probe local cosmic-ray accelerators and provide constraints on exotic production mechanisms such as annihilation of dark matter particles. We present a high-statistics measurement of the spectrum of CRe candidate events from 0.3 to 40 TeV with the High Energy Stereoscopic System (H.E.S.S.), covering two orders of magnitude in energy and reaching a proton rejection power of better than $10^{4}$. The measured spectrum is well described by a broken power law, with a break around 1 TeV, where the spectral index increases from $\Gamma_1 = 3.25$ $\pm$ 0.02 (stat) $\pm$ 0.2 (sys) to $\Gamma_2 = 4.49$ $\pm$ 0.04 (stat) $\pm$ 0.2 (sys). Apart from the break, the spectrum is featureless. The absence of distinct signatures at multi-TeV energies imposes constraints on the presence of nearby CRe accelerators and the local CRe propagation mechanisms., Comment: main paper: 8 pages, 4 figures, supplemental material: 12 pages, 14 figures, accepted for publication in Physical Review Letters https://journals.aps.org/prl/

Published
2024
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2. A retrospective study of antimicrobial susceptibility pattern of aerobic microbial isolates from urine samples of patients attending a tertiary care hospital

Author

Ahmad S, Jahan N, Ahmad SS, Singh N, and Khatoon R

Subjects
aerobic microbial isolates, urinary tract infection, antimicrobial susceptibility test, retrospective analysis, Medicine (General), R5-920
Abstract

Background: Urinary tract infections (UTIs) are one of the most common infections encountered in clinical practice. Objective: This is a retrospective study to evaluate the antimicrobial susceptibility pattern of aerobic microbial isolates from urine samples of patients with complaints suggestive of UTI. Materials and methods: A total of 3116 urine samples which were received in the Department of Microbiology during the study period from April 2018 to March 2019 were analyzed. Results: Out of 3116 urine samples from both outpatient (OPD) and inpatient department (IPD), 2614 samples showed either growth of contaminants or insignificant or no growth of microorganisms, whereas, 502 samples showed significant microbial growth on aerobic culture giving overall prevalence of UTI in the study population to be 16.1%. Of these 502 culture positives, majority was found to be from OPD (51.0%) patients, amongst females (62.9%), and Escherichia coli being the commonest isolate (49.8%). The antibiotic sensitivity of uroisolates of Escherichia coli were found to range from 46.0-70.0%. Conclusion: In view of the increasing drug resistance amongst pathogens causing UTI, antimicrobial susceptibility should be done before initiating definitive therapy. These data may be used to formulate local antibiotic policies in order to assist clinicians in the rationale use of antibiotics.

Published
2021
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3. Multi-wavelength study of OT 081: broadband modelling of a transitional blazar

Author

MAGIC Collaboration, Abe, H., Abe, S., Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., de Almeida, U. Barres, Batković, I., Baxter, J., Bernardini, E., Bernardos, M., Bernete, J., Berti, A., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Chai, Y., Cifuentes, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fukami, S., Fukazawa, Y., López, R. J. García, Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Grau, R., Green, J. G., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Imazawa, R., Inada, T., Iotov, R., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kubo, H., Kushida, J., Lezáun, M. Láinez, Lamastra, A., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miranda, J. M., Mirzoyan, R., Molina, E., Mondal, H. A., Morcuende, D., Nanci, C., Neustroev, V., Nigro, C., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sitarek, J., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Suda, Y., Surić, T., Suutarinen, S., Tajima, H., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Ubach, S., van Scherpenberg, J., Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Walter, R., Yamamoto, T., Collaborators, Benkhali, F. Ait, Becherini, Y., Bi, B., Böttcher, M., Bolmont, J., Brown, A., Bulik, T., Casanova, S., Chand, T., Chandra, S., Chibueze, J., Chibueze, O., Egberts, K., Einecke, S., Ernenwein, J. -P., Fontaine, G., Gabici, S., Goswami, P., Holler, M., Jamrozy, M., Joshi, V., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluzniak, W., Kosack, K., Stum, S. Le, Lemière, A., Marx, R., Moderski, R., Moghadam, M. O., de Naurois, M., Niemiec, J., O'Brien, P., Ostrowski, M., Peron, G., Pita, S., Pühlhofer, G., Quirrenbach, A., Rudak, B., Sahakian, V., Sanchez, D. A., Santangelo, A., Sasaki, M., Schutte, H. M., Seglar-Arroyo, M., Shapopi, J. N. S., Steenkamp, R., Steppa, C., Suzuki, H., Tanaka, T., Tluczykont, M., Venter, C., Wagner, S. J., Wierzcholska, A., Zdziarski, A. A., Żywucka, N., Collaboration, Fermi-LAT, González, J. Becerra, Ciprini, S., Venters, T. M., collaborators, MWL, D'Ammando, F., Esteban-Gutiérrez, A., Ramazani, V. Fallah, Filippenko, A. V., Hovatta, T., Jermak, H., Jorstad, S., Kiehlmann, S., Lähteenmäki, A., Larionov, V. M., Larionova, E., Marscher, A. P., Morozova, D., Max-Moerbeck, W., Readhead, A. C. S., Reeves, R., Steele, I. A., Tornikoski, M., Verrecchia, F., Xiao, H., and Zheng, W.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

OT 081 is a well-known, luminous blazar that is remarkably variable in many energy bands. We present the first broadband study of the source which includes very-high-energy (VHE, $E>$100\,GeV) $\gamma$-ray data taken by the MAGIC and H.E.S.S. imaging Cherenkov telescopes. The discovery of VHE $\gamma$-ray emission happened during a high state of $\gamma$-ray activity in July 2016, observed by many instruments from radio to VHE $\gamma$-rays. We identify four states of activity of the source, one of which includes VHE $\gamma$-ray emission. Variability in the VHE domain is found on daily timescales. The intrinsic VHE spectrum can be described by a power-law with index $3.27\pm0.44_{\rm stat}\pm0.15_{\rm sys}$ (MAGIC) and $3.39\pm0.58_{\rm stat}\pm0.64_{\rm sys}$ (H.E.S.S.) in the energy range of 55--300\,GeV and 120--500\,GeV, respectively. The broadband emission cannot be sucessfully reproduced by a simple one-zone synchrotron self-Compton model. Instead, an additional external Compton component is required. We test a lepto-hadronic model that reproduces the dataset well and a proton-synchrotron dominated model that requires an extreme proton luminosity. Emission models that are able to successfully represent the data place the emitting region well outside of the Broad Line Region (BLR) to a location at which the radiative environment is dominated by the infrared thermal radiation field of the dusty torus. In the scenario described by this flaring activity, the source appears to be an FSRQ, in contrast with past categorizations. This suggests that the source can be considered to be a transitional blazar, intermediate between BL~Lac and FSRQ objects., Comment: Accepted on MNRAS Corresponding authors: M. Manganaro, J. Becerra Gonz\'alez, M. Seglar-Arroyo, D. A. Sanchez

Published
2024

4. Very-high-energy $\gamma$-ray emission from young massive star clusters in the Large Magellanic Cloud

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Böttcher, M., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Brose, R., Brown, A., Brun, F., Bruno, B., Burger-Scheidlin, C., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Cristofari, P., Devin, J., Djannati-Ataï, A., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Feijen, K., Filipovic, M., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glicenstein, J. F., Glombitza, J., Grolleron, G., Haerer, L., Heß, B., Hinton, J. A., Hofmann, W., Holch, T. L., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Mackey, J., Marandon, V., Martí-Devesa, G., Marx, R., Mehta, A., Mitchell, A., Moderski, R., Moghadam, M. O., Mohrmann, L., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Pensec, U., Peron, G., Pühlhofer, G., Quirrenbach, A., Ravikularaman, S., Regeard, M., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sabri, K., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schutte, H. M., Sol, H., Spencer, S., Stawarz, Ł., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Taylor, A. M., Terrier, R., Tsirou, M., Tsuji, N., van Eldik, C., Vecchi, M., Venter, C., Vink, J., Wagner, S. J., White, R., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Tarantula Nebula in the Large Magellanic Cloud is known for its high star formation activity. At its center lies the young massive star cluster R136, providing a significant amount of the energy that makes the nebula shine so brightly at many wavelengths. Recently, young massive star clusters have been suggested to also efficiently produce high-energy cosmic rays, potentially beyond PeV energies. Here, we report the detection of very-high-energy $\gamma$-ray emission from the direction of R136 with the High Energy Stereoscopic System, achieved through a multicomponent, likelihood-based modeling of the data. This supports the hypothesis that R136 is indeed a very powerful cosmic-ray accelerator. Moreover, from the same analysis, we provide an updated measurement of the $\gamma$-ray emission from 30 Dor C, the only superbubble detected at TeV energies presently. The $\gamma$-ray luminosity above $0.5\,\mathrm{TeV}$ of both sources is $(2-3)\times 10^{35}\,\mathrm{erg}\,\mathrm{s}^{-1}$. This exceeds by more than a factor of 2 the luminosity of HESS J1646$-$458, which is associated with the most massive young star cluster in the Milky Way, Westerlund 1. Furthermore, the $\gamma$-ray emission from each source is extended with a significance of $>3\sigma$ and a Gaussian width of about $30\,\mathrm{pc}$. For 30 Dor C, a connection between the $\gamma$-ray emission and the nonthermal X-ray emission appears likely. Different interpretations of the $\gamma$-ray signal from R136 are discussed., Comment: 10+11 pages, 4+6 figures. Corresponding authors: L. Mohrmann, N. Komin

Published
2024
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5. H.E.S.S. observations of the 2021 periastron passage of PSR B1259-63/LS 2883

Author

Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaoui, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Devin, J., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Ernenwein, J. -P., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Haerer, L., Heß, B., Hofmann, W., Holch, T. L., Holler, M., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khangulyan, D., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Mackey, J., Malyshev, D., Martí-Devesa, G., Marx, R., Mehta, A., Meintjes, P. J., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Ohm, S., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Pensec, U., Peron, G., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reimer, A., Reimer, O., Reis, I., Ren, H., Rieger, F., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tluczykont, M., Unbehaun, T., van Eldik, C., van Soelen, B., Vecchi, M., Venter, C., Vink, J., Wach, T., Wagner, S. J., Werner, F., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

PSR B1259-63 is a gamma-ray binary system that hosts a pulsar in an eccentric orbit, with a 3.4 year period, around an O9.5Ve star. At orbital phases close to periastron passages, the system radiates bright and variable non-thermal emission. We report on an extensive VHE observation campaign conducted with the High Energy Stereoscopic System, comprised of ~100 hours of data taken from $t_p-24$ days to $t_p+127$ days around the system's 2021 periastron passage. We also present the timing and spectral analyses of the source. The VHE light curve in 2021 is consistent with the stacked light curve of all previous observations. Within the light curve, we report a VHE maximum at times coincident with the third X-ray peak first detected in the 2021 X-ray light curve. In the light curve -- although sparsely sampled in this time period -- we see no VHE enhancement during the second disc crossing. In addition, we see no correspondence to the 2021 GeV flare in the VHE light curve. The VHE spectrum obtained from the analysis of the 2021 dataset is best described by a power law of spectral index $\Gamma = 2.65 \pm 0.04_{\text{stat}}$ $\pm 0.04_{\text{sys}}$, a value consistent with the previous H.E.S.S. observations of the source. We report spectral variability with a difference of $\Delta \Gamma = 0.56 ~\pm~ 0.18_{\text{stat}}$ $~\pm~0.10_{\text{sys}}$ at 95% c.l., between sub-periods of the 2021 dataset. We also find a linear correlation between contemporaneous flux values of X-ray and TeV datasets, detected mainly after $t_p+25$ days, suggesting a change in the available energy for non-thermal radiation processes. We detect no significant correlation between GeV and TeV flux points, within the uncertainties of the measurements, from $\sim t_p-23$ days to $\sim t_p+126$ days. This suggests that the GeV and TeV emission originate from different electron populations., Comment: accepted to A&A

Published
2024

6. Unveiling extended gamma-ray emission around HESS J1813-178

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaoui, M., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chambery, P., Chand, T., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Djannati-Ataï, A., Dmytriiev, A., Doroshenko, V., Einecke, S., Ernenwein, J. -P., Feijen, K., Filipovic, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Gallant, Y. A., Ghafourizadeh, S., Giavitt, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M. -H., Hinton, J. A., Hofmann, W., Holch, T. L., Holler, M., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Katarzyński, K., Khatoon, R., Khélifi, B., Klepser, S., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Mackey, J., Malyshev, D., Marandon, V., Marinos, P., Martí-Devesa, G., Marx, R., Mehta, A., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Roellinghoff, G., Rudak, B., Sahakian, V., Salzmann, H., Sasaki, M., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Specovius, A., Spencer, S., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tluczykont, M., Tsuji, N., Unbehaun, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Vink, J., Wach, T., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zouari, S., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

HESS J1813$-$178 is a very-high-energy $\gamma$-ray source spatially coincident with the young and energetic pulsar PSR J1813$-$1749 and thought to be associated with its pulsar wind nebula (PWN). Recently, evidence for extended high-energy emission in the vicinity of the pulsar has been revealed in the Fermi Large Area Telescope (LAT) data. This motivates revisiting the HESS J1813$-$178 region, taking advantage of improved analysis methods and an extended data set. Using data taken by the High Energy Stereoscopic System (H.E.S.S.) experiment and the Fermi-LAT, we aim to describe the $\gamma$-ray emission in the region with a consistent model, to provide insights into its origin. We performed a likelihood-based analysis on 32 hours of H.E.S.S. data and 12 years of Fermi-LAT data and fit a spectro-morphological model to the combined datasets. These results allowed us to develop a physical model for the origin of the observed $\gamma$-ray emission in the region. In addition to the compact very-high-energy $\gamma$-ray emission centered on the pulsar, we find a significant yet previously undetected component along the Galactic plane. With Fermi-LAT data, we confirm extended high-energy emission consistent with the position and elongation of the extended emission observed with H.E.S.S. These results establish a consistent description of the emission in the region from GeV energies to several tens of TeV. This study suggests that HESS J1813$-$178 is associated with a $\gamma$-ray PWN powered by PSR J1813$-$1749. A possible origin of the extended emission component is inverse Compton emission from electrons and positrons that have escaped the confines of the pulsar and form a halo around the PWN., Comment: 13+5 pages, 13+11 figures. Accepted for publication in A&A. Corresponding authors: T.Wach, A.Mitchell, V.Joshi, P.Chamb\'ery

Published
2024
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7. Spectrum and extension of the inverse-Compton emission of the Crab Nebula from a combined Fermi-LAT and H.E.S.S. analysis

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chambery, P., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Cristofari, P., Devin, J., Djannati-Ataï, A., Djuvsland, J., Dmytriiev, A., Einecke, S., Ernenwein, J. -P., Fegan, S., Feijen, K., Filipović, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Gallant, Y. A., Giavitto, G., Glawion, D., Glicenstein, J. F., Glombitza, J., Goswami, P., Grolleron, G., Grondin, M. -H., Haerer, L., Hinton, J. A., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Luashvili, A., Mackey, J., Malyshev, D., Marandon, V., Marinos, P., Martí-Devesa, G., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Roellinghoff, G., Rudak, B., Sahakian, V., Salzmann, H., Sasaki, M., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tluczykont, M., Tsuji, N., Unbehaun, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Vink, J., Wach, T., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Żywucka, N., and Harding, A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Crab Nebula is a unique laboratory for studying the acceleration of electrons and positrons through their non-thermal radiation. Observations of very-high-energy $\gamma$ rays from the Crab Nebula have provided important constraints for modelling its broadband emission. We present the first fully self-consistent analysis of the Crab Nebula's $\gamma$-ray emission between 1 GeV and $\sim$100 TeV, that is, over five orders of magnitude in energy. Using the open-source software package Gammapy, we combined 11.4 yr of data from the Fermi Large Area Telescope and 80 h of High Energy Stereoscopic System (H.E.S.S.) data at the event level and provide a measurement of the spatial extension of the nebula and its energy spectrum. We find evidence for a shrinking of the nebula with increasing $\gamma$-ray energy. Furthermore, we fitted several phenomenological models to the measured data, finding that none of them can fully describe the spatial extension and the spectral energy distribution at the same time. Especially the extension measured at TeV energies appears too large when compared to the X-ray emission. Our measurements probe the structure of the magnetic field between the pulsar wind termination shock and the dust torus, and we conclude that the magnetic field strength decreases with increasing distance from the pulsar. We complement our study with a careful assessment of systematic uncertainties., Comment: 18+6 pages, 15+2 figures. Accepted for publication in A&A. Corresponding authors: M. Meyer, L. Mohrmann, T. Unbehaun. v2: after A&A language editing

Published
2024
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8. Curvature in the very-high energy gamma-ray spectrum of M87

Author

Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Bradascio, F., Brose, R., Brun, F., Bruno, B., Burger-Scheidlin, T. Bulik C., Bylund, T., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Collins, T., Cotter, G., Mbarubucyeye, J. Damascene, Djannati-Ataï, A., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Fegan, S., Fontaine, G., Funk, S., Gabici, S., Glicenstein, J. F., Glombitza, J., Grolleron, G., Haerer, L., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lypova, I., Luashvili, A., Mackey, J., Malyshev, D., Martí-Devesa, G., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Moghadam, M. O., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Panny, S., Panter, M., Parsons, R. D., Pensec, U., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reimer, A., Reimer, O., Ren, H., Reville, B., Rieger, F., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Sol, H., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Tsirou, M., van Eldik, C., Venter, C., Vink, J., Wach, T., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., Zilberman, P., and Zywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The radio galaxy M87 is a variable very-high energy (VHE) gamma-ray source, exhibiting three major flares reported in 2005, 2008, and 2010. Despite extensive studies, the origin of the VHE gamma-ray emission is yet to be understood. In this study, we investigate the VHE gamma-ray spectrum of M87 during states of high gamma-ray activity, utilizing 20.2$\,$ hours the H.E.S.S. observations. Our findings indicate a preference for a curved spectrum, characterized by a log-parabola model with extra-galactic background light (EBL) model above 0.3$\,$TeV at the 4$\sigma$ level, compared to a power-law spectrum with EBL. We investigate the degeneracy between the absorption feature and the EBL normalization and derive upper limits on EBL models mainly sensitive in the wavelength range 12.4$\,$$\mu$m - 40$\,$$\mu$m., Comment: 10 pages, 7 figures. Accepted for publication in A&A. Corresponding authors: Victor Barbosa Martins, Rahul Cecil, Iryna Lypova, Manuel Meyer, Perri Zilberman. Supplementary material: https://zenodo.org/records/10781524

Published
2024
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9. Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaou, M., Breuhau, M., Brose, R., Brown, A. M., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, J. Damascene, Djannati-Ataï, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P., Filipovic, M., Fontaine, G., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Grolleron, G., Haerer, L., Hinton, J. A., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Jardin-Blicq, A., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Klepser, S., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lenain, J. -P., Leuschner, F., Lohse, T., Luashvili, A., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Martí-Devesa, G., Marx, R., Mehta, A., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ricarte, H. Rueda, Ruiz-Velasco, E., Sahakian, V., Salzman, H., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schwanke, U., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Tsirou, M., Tsuji, N., Unbehaun, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Vink, J., Wach, T., Wagner, S. J., Werner, F., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

SS 433 is a microquasar, a stellar binary system with collimated relativistic jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic System (H.E.S.S.), finding an energy-dependent shift in the apparent position of the gamma-ray emission of the parsec-scale jets. These observations trace the energetic electron population and indicate the gamma rays are produced by inverse-Compton scattering. Modelling of the energy-dependent gamma-ray morphology constrains the location of particle acceleration and requires an abrupt deceleration of the jet flow. We infer the presence of shocks on either side of the binary system at distances of 25 to 30 parsecs and conclude that self-collimation of the precessing jets forms the shocks, which then efficiently accelerate electrons., Comment: Submitted 20th Apr. 2023, published 25th January 2024 (accepted version)

Published
2024
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10. The vanishing of the primary emission region in PKS 1510-089

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Y., Berge, D., Bernloehr, K., Bi, B., de Lavergne, M. de Bony, Boettcher, M., Boisson, C., Bolmont, J., Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brown, A. M., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Davids, I. D., Djannati-Atai, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P., Fegan, S., Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Haerer, L., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyski, K., Khatoon, R., Khelifi, B., Klu/'zniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemiere, A., Lenain, J. -P., Leuschner, F., Luashvili, A., Mackey, J., Marandon, V., Marchegiani, P., Marti-Devesa, G., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Peron, G., Prokhorov, D. A., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Rieger, F., Rowell, G., Rudak, B., Ricarte, H. Rueda, Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Schuessler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tsuji, N., van Eldik, C., van Soelen, B., Vecchi, M., Veh, J., Vink, J., Wach, T., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Zywucka, N., Buckley, D. A. H., Cooper, J., and Groenewald, D.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

In July 2021, PKS 1510-089 exhibited a significant flux drop in the high-energy gamma-ray (by a factor 10) and optical (by a factor 5) bands and remained in this low state throughout 2022. Similarly, the optical polarization in the source vanished, resulting in the optical spectrum being fully explained through the steady flux of the accretion disk and the broad-line region. Unlike the aforementioned bands, the very-high-energy gamma-ray and X-ray fluxes did not exhibit a significant flux drop from year to year. This suggests that the steady-state very-high-energy gamma-ray and X-ray fluxes originate from a different emission region than the vanished parts of the high-energy gamma-ray and optical jet fluxes. The latter component has disappeared through either a swing of the jet away from the line-of-sight or a significant drop in the photon production efficiency of the jet close to the black hole. Either change could become visible in high-resolution radio images., Comment: 18 pages, 4 figures, 6 tables; accepted for publication in ApJ Letters; corresponding authors: Joleen Barnard, Markus Boettcher, Hester Schutte, Michael Zacharias

Published
2023
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11. Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

Author

Acharyya, A., Adams, C. B., Archer, A., Bangale, P., Bartkoske, J. T., Batista, P., Benbow, W., Brill, A., Buckley, J. H., Christiansen, J. L., Chromey, A. J., Errando, M., Falcone, A., Feng, Q., Foote, G. M., Fortson, L., Furniss, A., Gallagher, G., Hanlon, W., Hanna, D., Hervet, O., Hinrichs, C. E., Hoang, J., Holder, J., Humensky, T. B., Jin, W., Kaaret, P., Kertzman, M., Kherlakian, M., Kieda, D., Kleiner, T. K., Korzoun, N., Kumar, S., Lang, M. J., Lundy, M., Maier, G., McGrath, C. E, Millard, M. J., Millis, J., Mooney, C. L., Moriarty, P., Mukherjee, R., O'Brien, S., Ong, R. A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Roache, E., Sadeh, I., Sadun, A. C., Saha, L., Santander, M., Sembroski, G. H., Shang, R., Splettstoesser, M., Talluri, A. Kaushik, Tucci, J. V., Vassiliev, V. V., Weinstein, A., Williams, D. A., Wong, S. L., Woo, J., Aharonian, F., Aschersleben, J., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlohr, K., Bi, B., Bottcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, J. Damascene, Djannati-Atai, A., Dmytriiev, A., Doroshenko, V., Einecke, S., Ernenwein, J. -P., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Fussling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Haerer, L., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Klepser, S., Kluzniak, W., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Lemiere, A., Lenain, J. P., Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marti-Devesa, G., Marx, R., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., Niemiec, J., Noel, A. Priyana, O'Brien, P., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Peron, G., Prokhorov, D. A., Puhlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Rieger, F., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Santangelo, A., Sasaki, M., Schafer, J., Schussler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Vink, J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Zywucka, N., and Mori, K.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2$^\circ$ away from the best-fit position of the IceCube neutrino event IceCube-211208A detected on December 8, 2021. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and high-energy components of the broadband spectral energy distribution (SED), and the gamma-ray data from Fermi -LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both X-ray and gamma-ray measurements provide strong constraints on the leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed SED. The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models and allow a proton jet power that marginally agrees with the Eddington limit in the lepto-hadronic model. We show a numerical lepto-hadronic model with external target photons that reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power., Comment: 21 pages, 3 figures, accepted by ApJ

Published
2023

12. Constraints on the intergalactic magnetic field using Fermi-LAT and H.E.S.S. blazar observations

Author

S., H. E. S., Collaborations, Fermi-LAT, Aharonian, F., Aschersleben, J., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bi, B., Bouyahiaoui, M., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., de Bony, M., Egberts, K., Ernenwein, J. -P., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grondin, M. -H., Haerer, L., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lenain, J. -P., Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Martí-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Murach, T., Nakashima, K., Niemiec, J., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sanchez, D. A., Sasaki, M., Schüussler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Sol, H., Spencer, S., Steinmassl, S., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., Veh, J., Venter, C., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zouari, S., and Zywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Magnetic fields in galaxies and galaxy clusters are believed to be the result of the amplification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron-positron pairs, which can subsequently initiate electromagnetic cascades. The $\gamma$-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of $B > 7.1\times10^{-16}$ G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of $10^4$ ($10^7$) yr, IGMF strengths below $1.8\times10^{-14}$ G ($3.9\times10^{-14}$ G) are excluded, which rules out specific models for IGMF generation in the early universe., Comment: 20 pages, 7 figures, 4 tables. Accepted for publication in ApJ Letters. Auxiliary data is provided in electronic format at https://zenodo.org/record/8014311

Published
2023
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13. Constraining the cosmic-ray pressure in the inner Virgo Cluster using H.E.S.S. observations of M 87

Author

Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Arcaro, C., Aschersleben, J., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Djannati-Ataï, A., Egberts, K., Ernenwein, J. -P., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M. -H., Haerer, L., Haupt, M., Hermann, G., Hinton, J. A., Holch, T. L., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marinos, P., Martí-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Panny, S., Panter, M., Parsons, R. D., Peron, G., Pita, S., Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Renaud, M., Rieger, F., Rowell, G., Rudak, B., Velasco, E. Ruiz, Sahakian, V., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schwanke, U., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., van Soelen, B., Vecchi, M., Veh, J., Venter, C., Vink, J., Wach, T., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

The origin of the gamma-ray emission from M87 is currently a matter of debate. This work aims to localize the VHE (100 GeV-100 TeV) gamma-ray emission from M87 and probe a potential extended hadronic emission component in the inner Virgo Cluster. The search for a steady and extended gamma-ray signal around M87 can constrain the cosmic-ray energy density and the pressure exerted by the cosmic rays onto the intra-cluster medium, and allow us to investigate the role of the cosmic rays in the active galactic nucleus feedback as a heating mechanism in the Virgo Cluster. H.E.S.S. telescopes are sensitive to VHE gamma rays and have been utilized to observe M87 since 2004. We utilized a Bayesian block analysis to identify M87 emission states with H.E.S.S. observations from 2004 until 2021, dividing them into low, intermediate, and high states. Because of the causality argument, an extended ($\gtrsim$kpc) signal is allowed only in steady emission states. Hence, we fitted the morphology of the 120h low state data and found no significant gamma-ray extension. Therefore, we derived for the low state an upper limit of 58"(corresponding to $\approx$4.6kpc) in the extension of a single-component morphological model described by a rotationally symmetric 2D Gaussian model at 99.7% confidence level. Our results exclude the radio lobes ($\approx$30 kpc) as the principal component of the VHE gamma-ray emission from the low state of M87. The gamma-ray emission is compatible with a single emission region at the radio core of M87. These results, with the help of two multiple-component models, constrain the maximum cosmic-ray to thermal pressure ratio $X_{{CR,max.}}$$\lesssim$$0.32$ and the total energy in cosmic-ray protons (CRp) to $U_{CR}$$\lesssim$5$\times10^{58}$ erg in the inner 20kpc of the Virgo Cluster for an assumed CRp power-law distribution in momentum with spectral index $\alpha_{p}$=2.1., Comment: 15 pages, 7 figures. Accepted for publication in A&A. Corresponding authors: Victor Barbosa Martins, Stefan Ohm, Cornelia Arcaro, Natalia \.Zywucka, Mathieu de Naurois

Published
2023
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14. H.E.S.S. follow-up observations of GRB221009A

Author

Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, J. Damascene, Devin, J., Djannati-Ataï, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P., Fegan, S., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Hinton, M. -H. Grondin J. A., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J. P., Leuschner, F., Lohse, T., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Martí-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tsuji, N., Uchiyama, Y., Vecchi, M., Venter, C., Vink, J., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., and Żywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

GRB221009A is the brightest gamma-ray burst ever detected. To probe the very-high-energy (VHE, $>$\!100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hours after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of $\Phi_\mathrm{UL}^{95\%} = 9.7 \times 10^{-12}~\mathrm{erg\,cm^{-2}\,s^{-1}}$ above $E_\mathrm{thr} = 650$ GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the SED occurring above the X-ray band. Compared to the VHE-bright GRB190829A, the upper limits for GRB221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB221009A, effectively ruling out an IC dominated scenario., Comment: 10 pages, 4 figures. Accepted for publication in APJL. Corresponding authors: J. Damascene Mbarubucyeye, H. Ashkar, S. J. Zhu, B. Reville, F. Sch\"ussler

Published
2023
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17. HESS observations of the 2021 periastron passage of PSR B1259-63/LS 2883

Author

Aharonian, F., Ait Benkhali, F., Aschersleben, J., Ashkar, H., Backes, M., Barbosa Martins, V., Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Boettcher, M., Boisson, C., Bolmont, J., de Bony de Lavergne, M., Borowska, J., Bouyahiaoui, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Damascene Mbarubucyeye, J., Devin, J., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Ernenwein, J. -p., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Haerer, L., Hess, B., Hofmann, W., Holch, T. L., Holler, M., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khangulyan, D., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -p., Leuschner, F., Mackey, J., Malyshev, D., Marti-Devesa, G., Marx, R., Mehta, A., Meintjes, P. J., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Ohm, S., de Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Pensec, U., Peron, G., Prokhorov, D. A., Puehlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reimer, A., Reimer, O., Reis, I., Ren, H., Rieger, F., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schaefer, J., Schuessler, F., Schutte, H. M., Shapopi, J. N. S., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tluczykont, M., Unbehaun, T., van Eldik, C., van Soelen, B., Vecchi, M., Venter, C., Vink, J., Wach, T., Wagner, S. J., Werner, F., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., Zywucka, N., Aharonian, F., Ait Benkhali, F., Aschersleben, J., Ashkar, H., Backes, M., Barbosa Martins, V., Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Boettcher, M., Boisson, C., Bolmont, J., de Bony de Lavergne, M., Borowska, J., Bouyahiaoui, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Damascene Mbarubucyeye, J., Devin, J., Djuvsland, J., Dmytriiev, A., Egberts, K., Einecke, S., Ernenwein, J. -p., Fontaine, G., Funk, S., Gabici, S., Gallant, Y. A., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Haerer, L., Hess, B., Hofmann, W., Holch, T. L., Holler, M., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khangulyan, D., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Kundu, A., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -p., Leuschner, F., Mackey, J., Malyshev, D., Marti-Devesa, G., Marx, R., Mehta, A., Meintjes, P. J., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Ohm, S., de Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Pensec, U., Peron, G., Prokhorov, D. A., Puehlhofer, G., Punch, M., Quirrenbach, A., Regeard, M., Reimer, A., Reimer, O., Reis, I., Ren, H., Rieger, F., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schaefer, J., Schuessler, F., Schutte, H. M., Shapopi, J. N. S., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Streil, K., Sushch, I., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tluczykont, M., Unbehaun, T., van Eldik, C., van Soelen, B., Vecchi, M., Venter, C., Vink, J., Wach, T., Wagner, S. J., Werner, F., Wierzcholska, A., Zacharias, M., Zdziarski, A. A., Zech, A., and Zywucka, N.

Abstract

PSR B1259-63/LS 2883 is a gamma-ray binary system that hosts a pulsar in an eccentric orbit, with a 3.4 yr period, around an O9.5Ve star (LS 2883). At orbital phases close to periastron passages, the system radiates bright and variable non-thermal emission, for which the temporal and spectral properties of this emission are, for now, poorly understood. In this regard, very high-energy (VHE) emission is especially useful to study and constrain radiation processes and particle acceleration in the system. We report on an extensive VHE observation campaign conducted with the High Energy Stereoscopic System, comprised of approximately 100 h of data taken over five months, from t(p) - 24 days to t(p) + 127 days around the system's 2021 periastron passage (where t(p) is the time of periastron). We also present the timing and spectral analyses of the source. The VHE light curve in 2021 is consistent overall with the stacked light curve of all previous observations. Within the light curve, we report a VHE maximum at times coincident with the third X-ray peak first detected in the 2021 X-ray light curve. In the light curve - although sparsely sampled in this time period - we see no VHE enhancement during the second disc crossing. In addition, we see no correspondence to the 2021 GeV flare in the VHE light curve. The VHE spectrum obtained from the analysis of the 2021 dataset is best described by a power law of spectral index Gamma = 2.65 +/- 0.04(stat) +/- 0.04(sys), a value consistent with the spectral index obtained from the analysis of data collected with H.E.S.S. during the previous observations of the source. We report spectral variability with a difference of Delta Gamma = 0.56 +/- 0.18(stat) +/- 0.10(sys) at 95% confidence intervals, between sub-periods of the 2021 dataset. We also detail our investigation into X-ray/TeV and GeV/TeV flux correlations in the 2021 periastron passage. We find a linear correlation between contemporaneous flux values of X-ray and TeV datase

Published
2024
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18. TeV flaring activity of the AGN PKS 0625-354 in November 2018

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Bi, B., Bottcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Davids, I. D., Djuvsland, J., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P, Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Glombitza, J., Goswami, P., Grolleron, G., Haerer, L., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lenain, J. -P, Leuschner, F., Luashvili, A., Mackey, J., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Parsons, R. D., Pita, S., Prokhorov, D. A., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Rieger, F., Rudak, B., Sahakian, V., Salzmann, H., Sanchez, D. A., Sasaki, M., Schuessler, F., Schutte, H. M., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Zywucka, N., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Bi, B., Bottcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Davids, I. D., Djuvsland, J., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P, Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Glombitza, J., Goswami, P., Grolleron, G., Haerer, L., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lenain, J. -P, Leuschner, F., Luashvili, A., Mackey, J., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Parsons, R. D., Pita, S., Prokhorov, D. A., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Rieger, F., Rudak, B., Sahakian, V., Salzmann, H., Sanchez, D. A., Sasaki, M., Schuessler, F., Schutte, H. M., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., and Zywucka, N.

Abstract

Most gamma-ray detected active galactic nuclei are blazars with one of their relativistic jets pointing towards the Earth. Only a few objects belong to the class of radio galaxies or misaligned blazars. Here, we investigate the nature of the object PKS 0625-354, its gamma-ray flux and spectral variability and its broad-band spectral emission with observations from H.E.S.S., Fermi-LAT, Swift-XRT, and UVOT taken in November 2018. The H.E.S.S. light curve above 200 GeV shows an outburst in the first night of observations followed by a declining flux with a halving time scale of 5.9 h. The gamma gamma-opacity constrains the upper limit of the angle between the jet and the line of sight to similar to 10 degrees. The broad-band spectral energy distribution shows two humps and can be well fitted with a single-zone synchrotron self Compton emission model. We conclude that PKS 0625-354, as an object showing clear features of both blazars and radio galaxies, can be classified as an intermediate active galactic nuclei. Multi-wavelength studies of such intermediate objects exhibiting features of both blazars and radio galaxies are sparse but crucial for the understanding of the broad-band emission of gamma-ray detected active galactic nuclei in general.

Published
2024
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19. TeV flaring activity of the AGN PKS 0625-354 in November 2018

Author

Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Davids, I. D., Djuvsland, J., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Glombitza, J., Goswami, P., Grolleron, G., Haerer, L., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Kh'elifi, B., z, niak, Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lenain, J. -P., Leuschner, F., Luashvili, A., Mackey, J., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Parsons, R. D., Pita, S., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Rieger, F., Rudak, B., Sahakian, V., Salzmann, H., Sanchez, D. A., Sasaki, M., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., L., Stawarz, Steenkamp, R., Steinmassl, S., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Żywucka, N., Collaboration, H. E. S. S., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Martins, V. Barbosa, Barnard, J., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brown, A., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Mbarubucyeye, J. Damascene, Davids, I. D., Djuvsland, J., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Glombitza, J., Goswami, P., Grolleron, G., Haerer, L., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Kh'elifi, B., z, niak, Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Stum, S. Le, Leitl, F., Lemière, A., Lenain, J. -P., Leuschner, F., Luashvili, A., Mackey, J., Marx, R., Mehta, A., Meyer, M., Mitchell, A., Moderski, R., Montanari, A., Moulin, E., de Naurois, M., Niemiec, J., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Parsons, R. D., Pita, S., Prokhorov, D. A., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Rieger, F., Rudak, B., Sahakian, V., Salzmann, H., Sanchez, D. A., Sasaki, M., Schüssler, F., Schutte, H. M., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., L., Stawarz, Steenkamp, R., Steinmassl, S., Streil, K., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., van Eldik, C., Vecchi, M., Veh, J., Venter, C., Wagner, S. J., Wierzcholska, A., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., and Żywucka, N.

Abstract

Most $\gamma$-ray detected active galactic nuclei are blazars with one of their relativistic jets pointing towards the Earth. Only a few objects belong to the class of radio galaxies or misaligned blazars. Here, we investigate the nature of the object PKS 0625-354, its $\gamma$-ray flux and spectral variability and its broad-band spectral emission with observations from H.E.S.S., Fermi-LAT, Swift-XRT, and UVOT taken in November 2018. The H.E.S.S. light curve above 200 GeV shows an outburst in the first night of observations followed by a declining flux with a halving time scale of 5.9h. The $\gamma\gamma$-opacity constrains the upper limit of the angle between the jet and the line of sight to $\sim10^\circ$. The broad-band spectral energy distribution shows two humps and can be well fitted with a single-zone synchrotron self Compton emission model. We conclude that PKS 0625-354, as an object showing clear features of both blazars and radio galaxies, can be classified as an intermediate active galactic nuclei. Multi-wavelength studies of such intermediate objects exhibiting features of both blazars and radio galaxies are sparse but crucial for the understanding of the broad-band emission of $\gamma$-ray detected active galactic nuclei in general., Comment: 9 pages, 6 figures, accepted for publication in Astronomy & Astrophysics

Published
2024

20. Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

Author

Acharyya, A., primary, Adams, C. B., additional, Archer, A., additional, Bangale, P., additional, Bartkoske, J. T., additional, Batista, P., additional, Benbow, W., additional, Brill, A., additional, Buckley, J. H., additional, Christiansen, J. L., additional, Chromey, A. J., additional, Errando, M., additional, Falcone, A., additional, Feng, Q., additional, Foote, G. M., additional, Fortson, L., additional, Furniss, A., additional, Gallagher, G., additional, Hanlon, W., additional, Hanna, D., additional, Hervet, O., additional, Hinrichs, C. E., additional, Hoang, J., additional, Holder, J., additional, Humensky, T. B., additional, Jin, W., additional, Kaaret, P., additional, Kertzman, M., additional, Kherlakian, M., additional, Kieda, D., additional, Kleiner, T. K., additional, Korzoun, N., additional, Kumar, S., additional, Lang, M. J., additional, Lundy, M., additional, Maier, G., additional, McGrath, C. E, additional, Millard, M. J., additional, Millis, J., additional, Mooney, C. L., additional, Moriarty, P., additional, Mukherjee, R., additional, O’Brien, S., additional, Ong, R. A., additional, Pohl, M., additional, Pueschel, E., additional, Quinn, J., additional, Ragan, K., additional, Reynolds, P. T., additional, Ribeiro, D., additional, Roache, E., additional, Sadeh, I., additional, Sadun, A. C., additional, Saha, L., additional, Santander, M., additional, Sembroski, G. H., additional, Shang, R., additional, Splettstoesser, M., additional, Talluri, A. Kaushik, additional, Tucci, J. V., additional, Vassiliev, V. V., additional, Weinstein, A., additional, Williams, D. A., additional, Wong, S. L., additional, Woo, J., additional, Aharonian, F., additional, Aschersleben, J., additional, Backes, M., additional, Martins, V. Barbosa, additional, Batzofin, R., additional, Becherini, Y., additional, Berge, D., additional, Bernlöhr, K., additional, Bi, B., additional, Böttcher, M., additional, Boisson, C., additional, Bolmont, J., additional, de Bony de Lavergne, M., additional, Borowska, J., additional, Bouyahiaoui, M., additional, Bradascio, F., additional, Breuhaus, M., additional, Brose, R., additional, Brun, F., additional, Bruno, B., additional, Bulik, T., additional, Burger-Scheidlin, C., additional, Caroff, S., additional, Casanova, S., additional, Cecil, R., additional, Celic, J., additional, Cerruti, M., additional, Chand, T., additional, Chandra, S., additional, Chen, A., additional, Chibueze, J., additional, Chibueze, O., additional, Cotter, G., additional, Dai, S., additional, Mbarubucyeye, J. Damascene, additional, Djannati-Ataï, A., additional, Dmytriiev, A., additional, Doroshenko, V., additional, Einecke, S., additional, Ernenwein, J.-P., additional, de Clairfontaine, G. Fichet, additional, Filipovic, M., additional, Fontaine, G., additional, Füßling, M., additional, Funk, S., additional, Gabici, S., additional, Ghafourizadeh, S., additional, Giavitto, G., additional, Glawion, D., additional, Glicenstein, J. F., additional, Goswami, P., additional, Grolleron, G., additional, Haerer, L., additional, Hinton, J. A., additional, Holch, T. L., additional, Holler, M., additional, Horns, D., additional, Jamrozy, M., additional, Jankowsky, F., additional, Joshi, V., additional, Jung-Richardt, I., additional, Kasai, E., additional, Katarzyński, K., additional, Khatoon, R., additional, Khélifi, B., additional, Klepser, S., additional, Kluźniak, W., additional, Kosack, K., additional, Kostunin, D., additional, Lang, R. G., additional, Le Stum, S., additional, Lemière, A., additional, Lenain, J.-P., additional, Leuschner, F., additional, Lohse, T., additional, Luashvili, A., additional, Lypova, I., additional, Mackey, J., additional, Malyshev, D., additional, Marandon, V., additional, Marchegiani, P., additional, Marcowith, A., additional, Martí-Devesa, G., additional, Marx, R., additional, Mitchell, A., additional, Moderski, R., additional, Mohrmann, L., additional, Montanari, A., additional, Moulin, E., additional, Murach, T., additional, Nakashima, K., additional, Niemiec, J., additional, Noel, A. Priyana, additional, O’Brien, P., additional, Olivera-Nieto, L., additional, de Ona Wilhelmi, E., additional, Ostrowski, M., additional, Panny, S., additional, Panter, M., additional, Peron, G., additional, Prokhorov, D. A., additional, Pühlhofer, G., additional, Punch, M., additional, Quirrenbach, A., additional, Reichherzer, P., additional, Reimer, A., additional, Reimer, O., additional, Ren, H., additional, Renaud, M., additional, Rieger, F., additional, Rudak, B., additional, Ruiz-Velasco, E., additional, Sahakian, V., additional, Santangelo, A., additional, Sasaki, M., additional, Schäfer, J., additional, Schüssler, F., additional, Schutte, H. M., additional, Schwanke, U., additional, Shapopi, J. N. S., additional, Specovius, A., additional, Spencer, S., additional, Stawarz, Ł., additional, Steenkamp, R., additional, Steinmassl, S., additional, Sushch, I., additional, Suzuki, H., additional, Takahashi, T., additional, Tanaka, T., additional, Terrier, R., additional, van Eldik, C., additional, Vecchi, M., additional, Veh, J., additional, Venter, C., additional, Vink, J., additional, White, R., additional, Wierzcholska, A., additional, Wong, Yu Wun, additional, Zacharias, M., additional, Zargaryan, D., additional, Zdziarski, A. A., additional, Zech, A., additional, Zouari, S., additional, Żywucka, N., additional, and Mori, K., additional

Published
2023
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21. The Vanishing of the Primary Emission Region in PKS 1510–089

Author

Aharonian, F., primary, Benkhali, F. Ait, additional, Aschersleben, J., additional, Ashkar, H., additional, Backes, M., additional, Martins, V. Barbosa, additional, Barnard, J., additional, Batzofin, R., additional, Becherini, Y., additional, Berge, D., additional, Bernlöhr, K., additional, Bi, B., additional, de Bony de Lavergne, M., additional, Böttcher, M., additional, Boisson, C., additional, Bolmont, J., additional, Borowska, J., additional, Bouyahiaoui, M., additional, Bradascio, F., additional, Breuhaus, M., additional, Brose, R., additional, Brown, A. M., additional, Brun, F., additional, Bruno, B., additional, Bulik, T., additional, Burger-Scheidlin, C., additional, Caroff, S., additional, Casanova, S., additional, Cecil, R., additional, Celic, J., additional, Cerruti, M., additional, Chand, T., additional, Chandra, S., additional, Chen, A., additional, Chibueze, J., additional, Chibueze, O., additional, Cotter, G., additional, Damascene Mbarubucyeye, J., additional, Davids, I. D., additional, Djannati-Ataï, A., additional, Dmytriiev, A., additional, Doroshenko, V., additional, Egberts, K., additional, Einecke, S., additional, Ernenwein, J.-P., additional, Fegan, S., additional, Fontaine, G., additional, Füßling, M., additional, Funk, S., additional, Gabici, S., additional, Ghafourizadeh, S., additional, Giavitto, G., additional, Glawion, D., additional, Glicenstein, J. F., additional, Goswami, P., additional, Grolleron, G., additional, Haerer, L., additional, Hofmann, W., additional, Holch, T. L., additional, Holler, M., additional, Horns, D., additional, Jamrozy, M., additional, Jankowsky, F., additional, Joshi, V., additional, Jung-Richardt, I., additional, Kasai, E., additional, Katarzyński, K., additional, Khatoon, R., additional, Khélifi, B., additional, Kluźniak, W., additional, Komin, Nu., additional, Kosack, K., additional, Kostunin, D., additional, Lang, R. G., additional, Le Stum, S., additional, Leitl, F., additional, Lemière, A., additional, Lenain, J.-P., additional, Leuschner, F., additional, Luashvili, A., additional, Mackey, J., additional, Marandon, V., additional, Marchegiani, P., additional, Martí-Devesa, G., additional, Marx, R., additional, Mehta, A., additional, Meyer, M., additional, Mitchell, A., additional, Moderski, R., additional, Mohrmann, L., additional, Montanari, A., additional, Moulin, E., additional, de Naurois, M., additional, Niemiec, J., additional, Priyana Noel, A., additional, O’Brien, P., additional, Ohm, S., additional, Olivera-Nieto, L., additional, de Ona Wilhelmi, E., additional, Ostrowski, M., additional, Panny, S., additional, Panter, M., additional, Peron, G., additional, Prokhorov, D. A., additional, Pühlhofer, G., additional, Punch, M., additional, Quirrenbach, A., additional, Reichherzer, P., additional, Reimer, A., additional, Reimer, O., additional, Ren, H., additional, Rieger, F., additional, Rowell, G., additional, Rudak, B., additional, Ricarte, H. Rueda, additional, Ruiz-Velasco, E., additional, Sahakian, V., additional, Salzmann, H., additional, Sanchez, D. A., additional, Santangelo, A., additional, Sasaki, M., additional, Schüssler, F., additional, Schutte, H. M., additional, Schwanke, U., additional, Shapopi, J. N. S., additional, Sol, H., additional, Specovius, A., additional, Spencer, S., additional, Stawarz, Ł., additional, Steenkamp, R., additional, Steinmassl, S., additional, Steppa, C., additional, Sushch, I., additional, Suzuki, H., additional, Takahashi, T., additional, Tanaka, T., additional, Terrier, R., additional, Tsuji, N., additional, van Eldik, C., additional, van Soelen, B., additional, Vecchi, M., additional, Veh, J., additional, Vink, J., additional, Wach, T., additional, Wagner, S. J., additional, Wierzcholska, A., additional, Zacharias, M., additional, Zargaryan, D., additional, Zdziarski, A. A., additional, Zech, A., additional, Zouari, S., additional, Żywucka, N., additional, Buckley, D. A. H., additional, Cooper, J., additional, and Groenewald, D., additional

Published
2023
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22. Constraints on the Intergalactic Magnetic Field Using Fermi-LAT and H.E.S.S. Blazar Observations

Author

Aharonian, F., primary, Aschersleben, J., additional, Backes, M., additional, Martins, V. Barbosa, additional, Batzofin, R., additional, Becherini, Y., additional, Berge, D., additional, Bi, B., additional, Bouyahiaoui, M., additional, Breuhaus, M., additional, Brose, R., additional, Brun, F., additional, Bruno, B., additional, Bulik, T., additional, Burger-Scheidlin, C., additional, Bylund, T., additional, Caroff, S., additional, Casanova, S., additional, Celic, J., additional, Cerruti, M., additional, Chand, T., additional, Chandra, S., additional, Chen, A., additional, Chibueze, J., additional, Chibueze, O., additional, Cotter, G., additional, de Bony, M., additional, Egberts, K., additional, Ernenwein, J.-P., additional, de Clairfontaine, G. Fichet, additional, Filipovic, M., additional, Fontaine, G., additional, Füssling, M., additional, Funk, S., additional, Gabici, S., additional, Ghafourizadeh, S., additional, Giavitto, G., additional, Glawion, D., additional, Glicenstein, J. F., additional, Goswami, P., additional, Grondin, M.-H., additional, Haerer, L., additional, Holch, T. L., additional, Holler, M., additional, Horns, D., additional, Jamrozy, M., additional, Jankowsky, F., additional, Joshi, V., additional, Jung-Richardt, I., additional, Kasai, E., additional, Katarzyński, K., additional, Khatoon, R., additional, Khélifi, B., additional, Kluźniak, W., additional, Komin, Nu., additional, Kosack, K., additional, Kostunin, D., additional, Lang, R. G., additional, Le Stum, S., additional, Leitl, F., additional, Lemière, A., additional, Lenain, J.-P., additional, Leuschner, F., additional, Lohse, T., additional, Luashvili, A., additional, Lypova, I., additional, Mackey, J., additional, Malyshev, D., additional, Marandon, V., additional, Marchegiani, P., additional, Marcowith, A., additional, Martí-Devesa, G., additional, Marx, R., additional, Meyer, M., additional, Mitchell, A., additional, Moderski, R., additional, Mohrmann, L., additional, Montanari, A., additional, Moulin, E., additional, Muller, J., additional, Murach, T., additional, Nakashima, K., additional, Niemiec, J., additional, Ohm, S., additional, Olivera-Nieto, L., additional, de Ona Wilhelmi, E., additional, Panny, S., additional, Panter, M., additional, Parsons, R. D., additional, Peron, G., additional, Prokhorov, D. A., additional, Prokoph, H., additional, Pühlhofer, G., additional, Punch, M., additional, Quirrenbach, A., additional, Reichherzer, P., additional, Reimer, A., additional, Reimer, O., additional, Reville, B., additional, Rieger, F., additional, Rowell, G., additional, Rudak, B., additional, Ruiz-Velasco, E., additional, Sahakian, V., additional, Sanchez, D. A., additional, Sasaki, M., additional, Schüssler, F., additional, Schutte, H. M., additional, Schwanke, U., additional, Shapopi, J. N. S., additional, Sol, H., additional, Spencer, S., additional, Steinmassl, S., additional, Suzuki, H., additional, Takahashi, T., additional, Tanaka, T., additional, Taylor, A. M., additional, Terrier, R., additional, Thorpe-Morgan, C., additional, Tsirou, M., additional, Tsuji, N., additional, Uchiyama, Y., additional, van Eldik, C., additional, Veh, J., additional, Venter, C., additional, Wagner, S. J., additional, White, R., additional, Wierzcholska, A., additional, Wong, Yu Wun, additional, Zacharias, M., additional, Zargaryan, D., additional, Zdziarski, A. A., additional, Zouari, S., additional, and Żywucka, N., additional

Published
2023
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23. Constraints on the Intergalactic Magnetic Field Using Fermi-LAT and HESS Blazar Observations

Author

Aharonian, F., Aschersleben, J., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Yvonne, Berge, D., Bi, B., Bouyahiaoui, M., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, Tomas, Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., de Bony, M., Egberts, K., Ernenwein, J. -P, de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grondin, M. -H, Haerer, L., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lenain, J. -P, Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marti-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Murach, T., Nakashima, K., Niemiec, J., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sanchez, D. A., Sasaki, M., Schussler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Sol, H., Spencer, S., Steinmassl, S., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., Veh, J., Venter, C., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zouari, S., Zywucka, N., Aharonian, F., Aschersleben, J., Backes, M., Martins, V. Barbosa, Batzofin, R., Becherini, Yvonne, Berge, D., Bi, B., Bouyahiaoui, M., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, Tomas, Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., de Bony, M., Egberts, K., Ernenwein, J. -P, de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grondin, M. -H, Haerer, L., Holch, T. L., Holler, M., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lenain, J. -P, Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marti-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Murach, T., Nakashima, K., Niemiec, J., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sanchez, D. A., Sasaki, M., Schussler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Sol, H., Spencer, S., Steinmassl, S., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Thorpe-Morgan, C., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., Veh, J., Venter, C., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zouari, S., and Zywucka, N.

Abstract

Magnetic fields in galaxies and galaxy clusters are believed to be the result of the amplification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron-positron pairs, which can subsequently initiate electromagnetic cascades. The gamma-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of B > 7.1 x 10(-16) G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of 10(4) (10(7)) yr, IGMF strengths below 1.8 x 10(-14) G (3.9 x 10(-14) G) are excluded, which rules out specific models for IGMF generation in the early universe.

Published
2023
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24. HESS Follow-up Observations of GRB 221009A

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar., H., Backes., M., Baktash, A., Martins, V. Barbosa, Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Bi, B., Boettcher, M., Boisson, C., Bolmont, J., de Bony de Lavergne, M., Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, J. Damascene, Devin, J., Djannati-Atai, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P, Fegan, S., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M. -H, Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P, Leuschner, F., Lohse, T., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marti-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schaefer, J., Schuessler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tsuji, N., Uchiyama, Y., Vecchi, M., Venter, C., Vink, J., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zywucka, N., Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar., H., Backes., M., Baktash, A., Martins, V. Barbosa, Batzofin, R., Becherini, Yvonne, Berge, D., Bernloehr, K., Bi, B., Boettcher, M., Boisson, C., Bolmont, J., de Bony de Lavergne, M., Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, J. Damascene, Devin, J., Djannati-Atai, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J. -P, Fegan, S., de Clairfontaine, G. Fichet, Filipovic, M., Fontaine, G., Fuessling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M. -H, Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Kluzniak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P, Leuschner, F., Lohse, T., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marti-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Puehlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schaefer, J., Schuessler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tsuji, N., Uchiyama, Y., Vecchi, M., Venter, C., Vink, J., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., and Zywucka, N.

Abstract

GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of f(UL)(95%)=9.7x10(-12)ergcm(-2)s(-1) E-thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario.

Published
2023
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27. H.E.S.S. Follow-up Observations of GRB 221009A

Author

Aharonian, F., primary, Benkhali, F. Ait, additional, Aschersleben, J., additional, Ashkar, H., additional, Backes, M., additional, Baktash, A., additional, Martins, V. Barbosa, additional, Batzofin, R., additional, Becherini, Y., additional, Berge, D., additional, Bernlöhr, K., additional, Bi, B., additional, Böttcher, M., additional, Boisson, C., additional, Bolmont, J., additional, de Bony de Lavergne, M., additional, Borowska, J., additional, Bouyahiaoui, M., additional, Bradascio, F., additional, Breuhaus, M., additional, Brose, R., additional, Brun, F., additional, Bruno, B., additional, Bulik, T., additional, Burger-Scheidlin, C., additional, Caroff, S., additional, Casanova, S., additional, Celic, J., additional, Cerruti, M., additional, Chand, T., additional, Chandra, S., additional, Chen, A., additional, Chibueze, J., additional, Chibueze, O., additional, Cotter, G., additional, Dai, S., additional, Mbarubucyeye, J. Damascene, additional, Devin, J., additional, Djannati-Ataï, A., additional, Dmytriiev, A., additional, Doroshenko, V., additional, Egberts, K., additional, Einecke, S., additional, Ernenwein, J.-P., additional, Fegan, S., additional, de Clairfontaine, G. Fichet, additional, Filipovic, M., additional, Fontaine, G., additional, Füßling, M., additional, Funk, S., additional, Gabici, S., additional, Ghafourizadeh, S., additional, Giavitto, G., additional, Glawion, D., additional, Glicenstein, J. F., additional, Goswami, P., additional, Grolleron, G., additional, Grondin, M.-H., additional, Hinton, J. A., additional, Holch, T. L., additional, Holler, M., additional, Horns, D., additional, Huang, Zhiqiu, additional, Jamrozy, M., additional, Jankowsky, F., additional, Joshi, V., additional, Jung-Richardt, I., additional, Kasai, E., additional, Katarzyński, K., additional, Khatoon, R., additional, Khélifi, B., additional, Kluźniak, W., additional, Komin, Nu., additional, Konno, R., additional, Kosack, K., additional, Kostunin, D., additional, Lang, R. G., additional, Le Stum, S., additional, Leitl, F., additional, Lemière, A., additional, Lemoine-Goumard, M., additional, Lenain, J.-P., additional, Leuschner, F., additional, Lohse, T., additional, Lypova, I., additional, Mackey, J., additional, Malyshev, D., additional, Marandon, V., additional, Marchegiani, P., additional, Marcowith, A., additional, Martí-Devesa, G., additional, Marx, R., additional, Meyer, M., additional, Mitchell, A., additional, Mohrmann, L., additional, Montanari, A., additional, Moulin, E., additional, Murach, T., additional, Nakashima, K., additional, de Naurois, M., additional, Niemiec, J., additional, Noel, A. Priyana, additional, O’Brien, P., additional, Ohm, S., additional, Olivera-Nieto, L., additional, de Ona Wilhelmi, E., additional, Ostrowski, M., additional, Panny, S., additional, Panter, M., additional, Parsons, R. D., additional, Peron, G., additional, Prokhorov, D. A., additional, Prokoph, H., additional, Pühlhofer, G., additional, Punch, M., additional, Quirrenbach, A., additional, Reichherzer, P., additional, Reimer, A., additional, Reimer, O., additional, Ren, H., additional, Renaud, M., additional, Reville, B., additional, Rieger, F., additional, Rowell, G., additional, Rudak, B., additional, Ruiz-Velasco, E., additional, Sahakian, V., additional, Salzmann, H., additional, Santangelo, A., additional, Sasaki, M., additional, Schäfer, J., additional, Schüssler, F., additional, Schutte, H. M., additional, Schwanke, U., additional, Shapopi, J. N. S., additional, Specovius, A., additional, Spencer, S., additional, Stawarz, Ł., additional, Steenkamp, R., additional, Steinmassl, S., additional, Steppa, C., additional, Sushch, I., additional, Suzuki, H., additional, Takahashi, T., additional, Tanaka, T., additional, Terrier, R., additional, Tsuji, N., additional, Uchiyama, Y., additional, Vecchi, M., additional, Venter, C., additional, Vink, J., additional, Wagner, S. J., additional, White, R., additional, Wierzcholska, A., additional, Wong, Yu Wun, additional, Zacharias, M., additional, Zargaryan, D., additional, Zdziarski, A. A., additional, Zech, A., additional, Zhu, S. J., additional, and Żywucka, N., additional

Published
2023
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28. H.E.S.S. follow-up observations of GRB221009A

Author

Aharonian, F., Benkhali, F. Ait, Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Barbosa Martins, V., Batzofin, R., Becherini, Y., Berge, D., Bernlohr, K., Bi, B., Bottcher, M., Boisson, C., Bolmont, J., de Bony de Lavergne, M., Borowska, J., Bouyahiaoui, M., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Caroff, S., Casanova, S., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Dai, S., Mbarubucyeye, Jean Damascene, Devin, J., Djannati-Atai, A., Dmytriiev, A., Doroshenko, V., Egberts, K., Einecke, S., Ernenwein, J.-P., Fegan, S., Fichet de Clairfontaine, G., Filipovic, M., Fontaine, G., Fußling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M.-H., Hinton, J. A., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzynski, K., Khatoon, R., Khelifi, B., Klúzniak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemiere, A., Lemoine-Goumard, M., Lenain, J.-P., Leuschner, F., Lohse, T., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Martí-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Mohrmann, L., Montanari, A., Moulin, E., Murach, T., Nakashima, K., de Naurois, M., Niemiec, J., Noel, A. Priyana, O'Brien, P., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Prokhorov, D. A., Prokoph, H., Puhlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Ren, H., Renaud, M., Reville, B., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schafer, J., Schussler, F., Schutte, H. M., Schwanke, U., Shapopi, J. N. S., Specovius, A., Spencer, S., Stawarz, L., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Terrier, R., Tsuji, N., Uchiyama, Y., Vecchi, M., Venter, C., Vink, J., Wagner, S. J., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, Sylvia Jiechen, Zywucka, And N., and H. E. S. S. Collaboration

Subjects
electron, atmosphere, correction, flux, ratio, flux, upper limit, gamma ray, burst, brightness, X-ray, flux, GeV, VHE, energy, high, 5/3, HESS, synchrotron, energy, flux
Abstract

GRB221009A is the brightest gamma-ray burst ever detected. To probe the very-high-energy (VHE, $>$100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hours after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of $\Phi_\mathrm{UL}^{95\%} = 9.7 \times 10^{-12}~\mathrm{erg\,cm^{-2}\,s^{-1}}$ above $E_\mathrm{thr} = 650$ GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the SED occurring above the X-ray band. Compared to the VHE-bright GRB190829A, the upper limits for GRB221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB221009A, effectively ruling out an IC dominated scenario.

Published
2023
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29. Constraining the cosmic-ray pressure in the inner Virgo Cluster using H.E.S.S. observations of M 87

Author

Aharonian, F., Ait Benkhali, F., Arcaro, C., Aschersleben, J., Backes, M., Barbosa Martins, V., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., Borowska, J., Bradascio, F., Breuhaus, M., Brose, R., Brun, F., Bruno, B., Bulik, T., Burger-Scheidlin, C., Bylund, T., Caroff, S., Casanova, S., Cecil, R., Celic, J., Cerruti, M., Chand, T., Chandra, S., Chen, A., Chibueze, J., Chibueze, O., Cotter, G., Damascene Mbarubucyeye, J., Djannati-Ataï, A., Egberts, K., Ernenwein, J.-P., Fichet de Clairfontaine, G., Filipovic, M., Fontaine, G., Füßling, M., Funk, S., Gabici, S., Ghafourizadeh, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Goswami, P., Grolleron, G., Grondin, M.-H., Haerer, L., Haupt, M., Hermann, G., Hinton, J. A., Holch, T. L., Horns, D., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Khatoon, R., Khélifi, B., Kluźniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lang, R. G., Le Stum, S., Leitl, F., Lemière, A., Lemoine-Goumard, M., Lenain, J.-P., Leuschner, F., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Marinos, P., Martí-Devesa, G., Marx, R., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Nakashima, K., de Naurois, M., Niemiec, J., Priyana Noel, A., O’Brien, P., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Panny, S., Panter, M., Parsons, R. D., Peron, G., Pita, S., Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Renaud, M., Rieger, F., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schwanke, U., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, Ł., Steenkamp, R., Steinmassl, S., Steppa, C., Sushch, I., Suzuki, H., Takahashi, T., Tanaka, T., Taylor, A. M., Terrier, R., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., van Soelen, B., Vecchi, M., Veh, J., Venter, C., Vink, J., Wach, T., Wagner, S. J., White, R., Wierzcholska, A., Wong, Y. W., Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zouari, S., Żywucka, N., HESS Collaboration, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Deux Infinis Bordeaux (LP2I - Bordeaux), Université de Bordeaux (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), and H.E.S.S.

Subjects
gamma ray, emission, causality, VHE [gamma ray], gamma ray, VHE, cosmic radiation: energy, FOS: Physical sciences, energy, density, feedback, power spectrum, gamma ray: energy spectrum, Bayesian, rotation, thermal, cosmic radiation [p], energy [cosmic radiation], emission [gamma ray], HESS, TeV, cosmic radiation: pressure, energy: density, AGN, cluster, p, cosmic radiation, energy spectrum [gamma ray], High Energy Astrophysical Phenomena (astro-ph.HE), radio wave, cosmic radiation, energy, cosmic radiation, pressure, Astrophysics - Astrophysics of Galaxies, pressure [cosmic radiation], gamma ray: emission, VIRGO, gamma ray: VHE, p: cosmic radiation, Astrophysics of Galaxies (astro-ph.GA), ddc:520, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], density [energy]
Abstract

Astronomy and astrophysics 675, A138 (2023). doi:10.1051/0004-6361/202346056, The origin of the gamma-ray emission from M87 is currently a matter of debate. This work aims to localize the VHE (100 GeV-100 TeV) gamma-ray emission from M87 and probe a potential extended hadronic emission component in the inner Virgo Cluster. The search for a steady and extended gamma-ray signal around M87 can constrain the cosmic-ray energy density and the pressure exerted by the cosmic rays onto the intra-cluster medium, and allow us to investigate the role of the cosmic rays in the active galactic nucleus feedback as a heating mechanism in the Virgo Cluster. H.E.S.S. telescopes are sensitive to VHE gamma rays and have been utilized to observe M87 since 2004. We utilized a Bayesian block analysis to identify M87 emission states with H.E.S.S. observations from 2004 until 2021, dividing them into low, intermediate, and high states. Because of the causality argument, an extended ($\gtrsim$kpc) signal is allowed only in steady emission states. Hence, we fitted the morphology of the 120h low state data and found no significant gamma-ray extension. Therefore, we derived for the low state an upper limit of 58'(corresponding to $\approx$4.6kpc) in the extension of a single-component morphological model described by a rotationally symmetric 2D Gaussian model at 99.7% confidence level. Our results exclude the radio lobes ($\approx$30 kpc) as the principal component of the VHE gamma-ray emission from the low state of M87. The gamma-ray emission is compatible with a single emission region at the radio core of M87. These results, with the help of two multiple-component models, constrain the maximum cosmic-ray to thermal pressure ratio $X_{{CR,max.}}$$\lesssim$$0.32$ and the total energy in cosmic-ray protons (CRp) to $U_{CR}$$\lesssim$5$\times10^{58}$ erg in the inner 20kpc of the Virgo Cluster for an assumed CRp power-law distribution in momentum with spectral index $\alpha_{p}$=2.1., Published by EDP Sciences, Les Ulis

Published
2023
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31. Recent advance in MXenes: New horizons in electrocatalysis and environmental remediation technologies

Author

Khan, K, Tareen, AK, Iqbal, M, Zhang, Y, Mahmood, A, Mahmood, N, Yin, J, Khatoon, R, Zhang, H, Khan, K, Tareen, AK, Iqbal, M, Zhang, Y, Mahmood, A, Mahmood, N, Yin, J, Khatoon, R, and Zhang, H

Abstract

A strong electrocatalytic activity of the MXenes nanomaterials (NMs) has gained a lot of concentration as cutting edge materials in a variety of electrocatalytic devices in a broad range of industrial uses. In recent years, the production and utilization of the MXenes NMs as an electrocatalysts has progressed, with more than 50 distinct variants found and used. We reviewed and discussed in this article the latest detail progress in the synthesis, selected properties and potential applications of the MXenes as an electrocatalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting, oxygen reduction reaction (ORR), nitrogen reduction reaction (N2RR), CO2 reduction reaction (CO2RR) etc. We will also discuss the numerous approaches for increasing MXenes electrocatalytic activity for target products. At the end, we will also talk about the present obstacles and future suggestions for the MXenes as HER, ORR, OER, NO2RR and CO2RR electrocatalysts.

Published
2022

33. DISTRIBUTION AND DIET COMPOSITION OF TWO SYMPATRIC MONGOOSE SPECIES IN MURREE KAHUTA KOTLI SATTIAN NATIONAL PARK, PAKISTAN.

Author

Khatoon, R., Anwar, A., Khalil, S., and Habiba, U.

Subjects
*MONGOOSES, *NATIONAL parks & reserves, *CARNIVOROUS animals, *SPECIES, *DIET, *ODORS, *REPTILES
Abstract

Understanding the distribution and diet of carnivore is important to consider ecological role of species. As food is a critical resource for carnivore predators and its partitioning among sympatric species is crucial for their coexistence. The current study aimed at exploring distribution, diet composition, and diet breadth, niche overlap among two sympatric mongoose species occurring in Murree Kahuta Kotli Sattian National Park (MKKNP). 82 fecal samples were collected from 23 sites and recognized to species inside field based on morphology, odor, and extra signs. Presence signs of both species recorded from 23 survey sites. However, field diagnosis of small Indian Mongoose and Indian grey mongoose indicated presence at 12 and 14 sites, respectively. Fourteen dietary items were recovered in diet of small Indian mongoose i.e rodents, plant matter, insects and reptiles. The diet of Indian grey mongoose also comprised of (15) dietary items. Among both sympatric carnivores overall dietary breadth of Indian grey mongoose is narrow (BA = 0.5). as compared to small Indian mongoose (BA = 0.6). Moderate overlap was found between both mongoose species (0.62). [ABSTRACT FROM AUTHOR]

Published
2022
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34. Global research priorities on COVID-19 for maternal, newborn, child and adolescent health

Author

Ahmed, ASMNU, Maamri, A, Falade, AG, Ayede, AI, Bhutta, A, Gambhir, A, Tagarro, A, Abdelmegeid, A, Ahmadi, AR, Barros, AJD, Mekasha, A, Srinivasaiyer, AK, Araujo da Silva, AR, Schultz, A, Fatima, B, Dhar, B, Magowan, B, Wills, B, Raynes-Greenow, C, Homer, C, Maclennan, C, Ward, C, Garcia, DM, Ross, D, Murdoch, D, Wilson, DJ, Adejuyigbe, E, Stasii, E, Scudder, E, Sacks, E, McCollum, ED, Althabe, F, Russell, F, Kumar, GS, Sommerfelt, H, Graham, H, Blencowe, H, Tappis, H, Saloojee, H, Ben Masaud, HA, Tiwary, H, Asiodu, I, Newton, JB, Bourdaire, J, Adze, JA, Martines, J, Lozano, JM, Walson, J, Rankin, J, Allegaert, K, Pelle, KG, Edmond, K, Rabiei, K, Rasmussen, KM, Yunis, K, Ferguson, L, Greenslade, L, Kiapi, L, Noguchi, L, Bont, L, Day, LT, Mofenson, L, Aboumayaleh, M, Aquzouz, M, Wahba, M, Nagai, M, Knight, M, Melkumova, M, Jenyfa, M, Neuman, MI, Meremikwu, M, Kinney, M, Gravett, M, Hawkes, MT, Pacque, M, Walsh, M, McGuire, MK, AlShawafi, NA, Khuri-Bulos, N, Thacker, N, Rollins, N, Kissoon, N, Starets, O, Picone, O, Oladapo, OT, Erdeve, O, Smith, PB, Van de Perre, P, Kumar, P, Mangtani, P, Abbas, Q, Khatoon, R, Bahl, R, Lodha, R, Grais, R, Richards-Kortum, R, Rasaily, R, Aryeetey, R, Pattinson, R, Petrucci, R, Rossi, R, Pace, RM, Yoshida, S, Walani, SR, Godakandage, SSP, Bauler, S, Comstock, SS, Basu, S, Kebede, S, Saha, S, Bhatnagar, S, Lee, SK, Gupta, S, Antara, SN, Downe, S, Freedman, S, Lye, SJ, Miller, S, Sulimani, S, Ley, SH, Mangal, TD, Lavin, T, Shi, T, Florin, TA, Sundekilde, UK, Baltag, V, Valdes, V, Cherniak, W, Bin Nisar, Y, Shamszai, ZZ, Navabi, ZS, Ahmed, ASMNU, Maamri, A, Falade, AG, Ayede, AI, Bhutta, A, Gambhir, A, Tagarro, A, Abdelmegeid, A, Ahmadi, AR, Barros, AJD, Mekasha, A, Srinivasaiyer, AK, Araujo da Silva, AR, Schultz, A, Fatima, B, Dhar, B, Magowan, B, Wills, B, Raynes-Greenow, C, Homer, C, Maclennan, C, Ward, C, Garcia, DM, Ross, D, Murdoch, D, Wilson, DJ, Adejuyigbe, E, Stasii, E, Scudder, E, Sacks, E, McCollum, ED, Althabe, F, Russell, F, Kumar, GS, Sommerfelt, H, Graham, H, Blencowe, H, Tappis, H, Saloojee, H, Ben Masaud, HA, Tiwary, H, Asiodu, I, Newton, JB, Bourdaire, J, Adze, JA, Martines, J, Lozano, JM, Walson, J, Rankin, J, Allegaert, K, Pelle, KG, Edmond, K, Rabiei, K, Rasmussen, KM, Yunis, K, Ferguson, L, Greenslade, L, Kiapi, L, Noguchi, L, Bont, L, Day, LT, Mofenson, L, Aboumayaleh, M, Aquzouz, M, Wahba, M, Nagai, M, Knight, M, Melkumova, M, Jenyfa, M, Neuman, MI, Meremikwu, M, Kinney, M, Gravett, M, Hawkes, MT, Pacque, M, Walsh, M, McGuire, MK, AlShawafi, NA, Khuri-Bulos, N, Thacker, N, Rollins, N, Kissoon, N, Starets, O, Picone, O, Oladapo, OT, Erdeve, O, Smith, PB, Van de Perre, P, Kumar, P, Mangtani, P, Abbas, Q, Khatoon, R, Bahl, R, Lodha, R, Grais, R, Richards-Kortum, R, Rasaily, R, Aryeetey, R, Pattinson, R, Petrucci, R, Rossi, R, Pace, RM, Yoshida, S, Walani, SR, Godakandage, SSP, Bauler, S, Comstock, SS, Basu, S, Kebede, S, Saha, S, Bhatnagar, S, Lee, SK, Gupta, S, Antara, SN, Downe, S, Freedman, S, Lye, SJ, Miller, S, Sulimani, S, Ley, SH, Mangal, TD, Lavin, T, Shi, T, Florin, TA, Sundekilde, UK, Baltag, V, Valdes, V, Cherniak, W, Bin Nisar, Y, Shamszai, ZZ, and Navabi, ZS

Abstract

BACKGROUND: This research prioritization aimed to identify major research gaps in maternal, newborn, child and adolescent health (MNCAH) to help mitigate the direct and indirect effects of the COVID-19 pandemic. METHODS: We adapted the Child Health and Nutrition Research Initiative methodology. We defined scope, domains, themes and scoring criteria. We approached diverse global experts via email to submit their research ideas in MNCAH and MNCAH-related cross-cutting/health systems area. We curated the research ideas as research questions (RQs) and sent them to the consenting experts for scoring via the online link. For each RQ, the research priority score (RPS) was calculated as an average of individual criterion scores and ranked based on RPS in each area. RESULTS: We identified top-ranked 10 RQs in each maternal, newborn, and child and adolescent health and 5 in the cross-cutting/health systems area. In maternal health, indirect effects on care, measures to improve care, health risks and outcomes, and preventing and managing SARS-CoV-2 infection/COVID-19 disease were priority RQs. In newborn health, clinical characterization and managing SARS-CoV-2 infection/COVID-19 disease, mode of transmission and interventions to prevent transmission were the focus. For child and adolescent health, top-ranked RQs were indirect effects on care, clinical status and outcomes, interventions to protect against SARS-CoV-2 infection/COVID-19 disease, and educational institute-related RQs. The cross-cutting RQs were the effects of the pandemic on availability, access, care-seeking and utilization of MNCAH services and potential solutions. CONCLUSIONS: We call on partners, including governments, non-governmental organizations, research institutes, and donors, to address this urgent research agenda.

Published
2021

39. OCCURRENCE PATTERNS AND POPULATION DENSITY OF BARKING DEER (MUNTIACUS VAGINALIS) IN THE SOUTHERN SLOPES OF HIMALAYA FOOTHILLS, PUNJAB, PAKISTAN.

Author

Habiba, U., Anwar, M., Khatoon, R., Khan, B. M., and Nasir, K. A.

Subjects
POPULATION density, HABITAT conservation, DEER, MAMMAL populations, FOOTHILLS
Abstract

Barking deer is a small-sized cervid mammal and in Pakistan its population are limited to outer Himalayan foothill forests of Punjab Pakistan. They are usually associated with low but dense thorn scrub of Acacia modesta, Olea ferruginea and Zizyphus nummularia. Occupancy modelling was used to assess how environmental factors influence occurrence probabilities. The population parameters of barking deer were examined in Murree, Kotli-Sattian and Kahuta National Parks through direct visual observations and indirect signs of animal from 2015-2017. To estimate population density, distance sampling of the line transect data was employed. Mean population density was 0.27 individuals/km2. The range of encounter rates in each study site was 0.04 to 0.43 per km of transect. Population density in summer was higher (0.43/km2) than in winter (0.36/km2), possibly due to the addition of new-borns in May. The barking deer is basically a solitary animal. This species is endangered in Pakistan and its population are declining. Conservation efforts with focus on protection of disturbance-free habitat for barking deer are recommended in the study area. [ABSTRACT FROM AUTHOR]

Published
2020
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44. Prevalence of single umbilical artery, clinical outcomes and its risk factors: A cross-sectional study

Author

Homeira Vafaei, Khatoon Rafeei, Maryam Dalili, Nasrin Asadi, Nosaibe Seirfar, and Mojgan Akbarzadeh-Jahromi

Subjects
umbilical cord, single umbilical artery, pregnancy outcome, congenital abnormalities., Gynecology and obstetrics, RG1-991, Reproduction, QH471-489
Abstract

Background: Single umbilical artery (SUA) is found in 0.5–6% of all pregnancies worldwide. Although the association of SUA with some congenital malformations is mainly accepted, its effect on pregnancy/neonatal outcomes is still controversial. Objective: This is the first study aimed to approximate the SUA prevalence in southern part of Iran. SUA epidemiologic features accompanied by some of its effects on pregnancy/neonatal outcomes are investigated as well. Materials and Methods: In this cross-sectional study, data from two referral centers in Southern Iran were analyzed. In total, 1,469 pregnancies, fetuses, and neonates were examined for epidemiological features associated with SUA. SUA was confirmed by pathological examination, while congenital anomalies were diagnosed by clinical, ultrasound, and echocardiographical examinations. Data on pregnancy outcome were recorded based on the patients' medical records. Results: The prevalence of SUA was 3.47% (95% CI: 2.6–4.6%). Fetal anomalies including renal, cardiac, and other congenital anomalies, intrauterine fetal death, early neonatal death, low birth weight, low placental weight, and preterm birth were significantly higher in the SUA group (OR = 68.02, 31.04, 16.03, 3.85, 11.31, 3.22, 2.70, and 2.47, respectively). However, the maternal multiparity was lower in the SUA group (OR = 0.65; 95% CI: 0.44–0.98). Conclusion: A significant association was observed between SUA and increased risk of intrauterine fetal death and early neonatal death, as well as low birth weight and preterm birth. Obstetrical history of the mother like parity was identified as an important predictor of SUA. Further investigations are suggested on risk stratification of neonates in this regard.

Published
2021
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45. ChemInform Abstract: New Natural Products from Terrastrial Medicinal Plants and Marine Algae.

Author

AHMAD, V. U., primary, AHMAD, W. U., additional, ALIYA, R., additional, BAQUI, F. T., additional, GHAZALA, GHAZALA, additional, IQBAL, S., additional, KHATOON, R., additional, MOHAMMAD, F. V., additional, NOORWALA, M., additional, PERVEEN, S., additional, PERVEZ, A., additional, SABA, N., additional, SHAH, M. G., additional, and SIDDIQUI, S., additional

Published
2010
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49. Reproductive pathology. Repetitive complete hydatidiform mole can be biparental in origin and either male or female.

Author

Fisher, R.A., Khatoon, R., Paradinas, F.J., Roberts, A.P., and Newlands, E.S.

Abstract

Complete hydatidiform mole (CHM) is an abnormality in pregnancy due to a diploid conception which is generally androgenetic in origin, i.e. all 46 chromosomes are paternally derived. We have examined the genetic origin of repetitive hydatidiform moles in a patient having three CHM by two different partners, and no normal pregnancies. Using fluorescent microsatellite genotyping, we have shown all three CHM to be biparental, rather than androgenetic, in origin. Examination of informative markers for each homologous pair of chromosomes, in two of the CHM, failed to reveal any evidence of unipaternal disomy, suggesting that the molar phenotype might result from disruption of normal imprinting patterns due to a defect in the maternal genome. It has been suggested that intracytoplasmic sperm injection (ICSI), followed by selection of male embryos, can prevent repetitive CHM; but examination of sex chromosome-specific sequences in the three CHM described here, showed that, while two were female, the first CHM was male. Selection of male embryos is therefore unlikely to prevent repetitive CHM in this patient. Our results suggest that the genetic origin of repetitive CHM should be determined prior to in-vitro fertilization (IVF) and that current strategies for the prevention of repetitive CHM may not be appropriate where the CHM are of biparental origin. [ABSTRACT FROM PUBLISHER]

Published
2000
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