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5 results on '"Giada, Peron"'

1. On the Correlation between Young Massive Star Clusters and Gamma-Ray Unassociated Sources

Author

Giada Peron, Giovanni Morlino, Stefano Gabici, Elena Amato, Archana Purushothaman, and Marcella Brusa

Subjects
Gamma-ray astronomy, Gamma-ray sources, Galactic cosmic rays, Star clusters, Young star clusters, Astrophysics, QB460-466
Abstract

Star clusters (SCs) are potential cosmic-ray accelerators and therefore are expected to emit high-energy radiation. However, a clear detection of gamma-ray emission from this source class has only been possible for a handful of cases. This could in principle result from two different reasons: either detectable SCs are limited to a small fraction of the total number of Galactic SCs, or gamma-ray-emitting SCs are not recognized as such and therefore are listed in the ensemble of unidentified sources. In this Letter we investigate this latter scenario by comparing available catalogs of SCs and H ii regions, obtained from Gaia and Wide-field Infrared Survey Explorer observations, to the gamma-ray GeV and TeV catalogs built from Fermi Large Area Telescope (LAT), H.E.S.S., and LHAASO data. The significance of the correlation between catalogs is evaluated by comparing the results with simulations of synthetic populations. A strong correlation emerges between Fermi-LAT-unidentified sources and H ii regions that trace massive SCs in the earliest (≲1–2 Myr) phase of their life, where no supernova explosions have happened yet, confirming that winds of massive stars can alone accelerate particles and produce gamma-ray emission at least up to GeV energies. The association with TeV energy sources is less evident. Similarly, no significant association is found between Gaia SCs and GeV nor TeV sources. We ascribe this fact to the larger extension of these objects but also to an intrinsic bias in the Gaia selection toward SCs surrounded by a lower target gas density, which would otherwise hinder the detection in the optical wave band.

Published
2024
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2. The contribution of unresolved sources on the gamma-ray spectrum of molecular clouds

Author

Vittoria Vecchiotti, Giada Peron, Giulia Pagliaroli, Francesco Lorenzo Villante, 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, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
General Medicine, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Fermi-LAT observations of the large-scale diffuse gamma-ray emission unveiled that in some locations, towards the inner Galaxy, the spectrum of this component is harder than the local one, measured at the Earth position. If this signal is associated with the “truly” diffuse emission produced by the interaction of cosmic rays (CRs) with the interstellar medium (ISM) then its observed spectral features can be interpreted as indirect evidence of a CR spectral hardening toward the Galactic center. However, in order to correctly interpret the data, the contribution from unresolved sources has to be taken into account. Newly developed theoretical models showed that the cumulative flux produced by unresolved pulsar wind nebulae (PWNe) added to the “truly” diffuse emission significantly shapes the spectrum of the large-scale diffuse emission, challenging the CR spectral hardening hypothesis. In light of the recent results, we discuss the effect of unresolved PWNe on the observed spectra of the diffuse emission with a particular focus on molecular clouds (MCs). We analyze the influence of unresolved sources on clouds of different sizes and locations. Finally, we provide a prescription on how to choose the regions to target in order to have an unbiased determination of the “truly” diffuse emission.

Published
2022
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3. Detection of new Extreme BL Lac objects with H.E.S.S. and Swift XRT

Author

Angel Priyana Noel, Hassan Abdalla, Felix Aharonian, Faical Ait-Benkhali, Oguzhan Anguener, Cornelia Arcaro, Celine Armand, Tom Armstrong, Halim Ashkar, Michael Backes, Vardan Baghmanyan, Victor Barbosa Martins, Anna Barnacka, Monica Barnard, Rowan William Batzofin, Yvonne Becherini, David Berge, Konrad Bernloehr, Baiyang Bi, Markus Böttcher, Catherine Boisson, Julien Bolmont, Mathieu Bony (de), Mischa Breuhaus, Robert Brose, Francois Brun, Tomasz Bulik, Thomas Bylund, Floriane Cangemi, Sami Caroff, Sabrina Casanova, Jaqueline Catalano, Pauline Chambery, Tej Bahadur Chand, Andrew Chen, Garret Cotter, Malgorzata Curlo, Hannah Dalgleish, Jean Damascene Mbarubucyeye, Isak Delberth Davids, James Davies, Justine Devin, Arache Djannati-Ataï, Anton Dmytriev, Axel Donath, Victor Doroshenko, Lente Dreyer, Louis Du Plessis, Connor Duffy, Kathrin Egberts, Sabrina Einecke, Jean-Pierre ERNENWEIN, Steven Fegan, Kirsty Feijen, Armand Fiasson, Gaëtan Fichet de Clairfontaine, Gerard Fontaine, Lott Frans, Matthias Fuessling, Stefan Funk, Stefano Gabici, Yves Gallant, Gianluca Giavitto, Luca Giunti, Dorit Glawion, Jean-Francois Glicenstein, Marie-Hélène Grondin, Sumari Hattingh, Maria Haupt, German HERMANN, Jim Hinton, Werner Hofmann, Clemens Hoischen, Tim Holch, Markus Holler, Dieter Horns, Zhi-Qiu Huang, David Huber, Mario Hörbe, Marek Jamrozy, Felix Jankowsky, Vikas Joshi, Ira JUNG, Eli Kasai, Krzysztof Katarzynski, Ulì Katz, Dmitry Khangulyan, Bruno Khelifi, Stefan Klepser, Wlodek Kluzniak, Nukri Komin, Ruslan Konno, Karl Kosack, Dmitriy Kostunin, Michael Kreter, Gašper Kukec Mezek, Anu Kundu, Giovanni Lamanna, Sebastien Le Stum, Anne Lemiere, Marianne Lemoine-Goumard, Jean-Philippe Lenain, Fabian Leuschner, Christelle Levy, Thomas Lohse, Anna Luashvili, Iryna Lypova, Jonathan Mackey, Jhilik Majumdar, Denys Malyshev, Dmitry Malyshev, Vincent Marandon, Paolo Marchegiani, Alexandre Marcowith, Arnaud Mares, Guillem Martí-Devesa, Ramin Marx, Gilles Maurin, Pieter Meintjes, Manuel Meyer, Alison Mitchell, Rafal Moderski, Lars Mohrmann, Alessandro Montanari, Chris Moore, Paul Morris, Emmanuel Moulin, Jacques Muller, Thomas Murach, Kaori Nakashima, Mathieu Naurois (de), Amid Nayerhoda, Hambeleleni Davids, Jacek Niemiec, Paul O'Brien, Laenita Lorraine Oberholzer, Stefan Ohm, Laura Olivera-Nieto, Emma Ona-Wilhelmi (de), Michal Ostrowski, Sebastian Panny, Michael Panter, Dan Parsons, Giada Peron, Santiago Pita, Vincent Poireau, Dmitry A Prokhorov, Heike Prokoph, Gerd PUEHLHOFER, Michael Punch, Andreas Quirrenbach, Patrick Reichherzer, Anita Reimer, Olaf Reimer, Quentin Remy, Matthieu Renaud, Brian Reville, Frank Rieger, Carlo Romoli, Gavin P Rowell, Bronislaw Rudak, Hector Rueda Ricarte, Edna Ruiz Velasco, Vardan Sahakian, Simon Sailer, Heiko Salzmann, David Sanchez, Andrea Santangelo, Manami Sasaki, Johannes Schaefer, Hester Schutte, Ullrich Schwanke, Fabian Schüssler, Mohanraj Senniappan, Albert Seyffert, Jimmy N.S. Shapopi, Kleopas Shiningayamwe, Rachel Simoni, Atreyee Sinha, Helene Sol, Hugh Spackman, Andreas Specovius, Samuel Timothy Spencer, Marion Spir-Jacob, Lukasz Stawarz, Riaan Steenkamp, Christian Stegmann, Simon Steinmassl, Constantin Steppa, Lei Sun, Tadayuki Takahashi, Takaaki Tanaka, Thomas Tavernier, Andrew Taylor, Regis Terrier, Hannes Thiersen, Charles Thorpe-Morgan, Martin Tluczykont, Lenka Tomankova, Michelle Tsirou, Naomi Tsuji, Richard Tuffs, Yasunobu Uchiyama, Johann van der Walt, Christopher van Eldik, Carlo van Rensburg, Brian van Soelen, George Vasileiadis, Johannes Veh, Christo Venter, Pascal Vincent, Jacco Vink, Heinrich J. Völk, Stefan Wagner, Jason John Watson, Felix Werner, Richard White, Alicja Wierzcholska, Yu Wun Wong, Hend Mahmoud Yassin, Anke Yusafzai, Michael Zacharias, Roberta Zanin, Davit Zargaryan, Andrzej Zdziarski, Andreas Zech, Sylvia Zhu, Andreas Zmija, Samuel Zouari, Natalia Żywucka, 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), H.E.S.S., and Fermi-LAT

Subjects
accelerator, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, gamma ray: absorption, VHE, law.invention, blazar, X-ray, particle: acceleration, law, HESS, synchrotron, Radiative transfer, TeV, High Energy Stereoscopic System, 10. No inequality, Absorption (electromagnetic radiation), Blazar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Range (particle radiation), energy: high, redshift, Redshift, Synchrotron, Particle acceleration, spectral, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Extreme high synchrotron peaked blazars (EHBLs) are amongst the most powerful accelerators found in nature. Usually the synchrotron peak frequency of an EHBL is above $10^{17}\,$Hz, i.e., lies in the range of medium to hard X-rays making them ideal sources to study particle acceleration and radiative processes. EHBL objects are commonly observed at energies beyond several TeV, making them also powerful probes of gamma-ray absorption in the intergalactic medium. During the last decade, several attempts have been made to increase the number of EHBL detected at TeV energies and probe their spectral characteristics. Here we report new detections of EHBLs in the TeV energy regime, each at a redshift of less than 0.2, by the High Energy Stereoscopic System (H.E.S.S.). Also, we report on X-ray observations of these EHBLs candidates with Swift XRT. In conjunction with the very high energy observations, this allows us to probe the radiation mechanisms and the underlying particle acceleration processes., Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021)

Published
2022
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4. The young massive stellar cluster Westerlund 1 in gamma rays as seen with H.E.S.S

Author

Lars Mohrmann, Hassan Abdalla, Felix Aharonian, Faical Ait-Benkhali, Oguzhan Anguener, Cornelia Arcaro, Celine Armand, Tom Armstrong, Halim Ashkar, Michael Backes, Vardan Baghmanyan, Victor Barbosa Martins, Anna Barnacka, Monica Barnard, Rowan William Batzofin, Yvonne Becherini, David Berge, Konrad Bernloehr, Baiyang Bi, Markus Böttcher, Catherine Boisson, Julien Bolmont, Mathieu Bony (de), Mischa Breuhaus, Robert Brose, Francois Brun, Tomasz Bulik, Thomas Bylund, Floriane Cangemi, Sami Caroff, Sabrina Casanova, Jaqueline Catalano, Pauline Chambery, Tej Bahadur Chand, Andrew Chen, Garret Cotter, Malgorzata Curlo, Hannah Dalgleish, Jean Damascene Mbarubucyeye, Isak Delberth Davids, James Davies, Justine Devin, Arache Djannati-Ataï, Anton Dmytriev, Axel Donath, Victor Doroshenko, Lente Dreyer, Louis Du Plessis, Connor Duffy, Kathrin Egberts, Sabrina Einecke, Jean-Pierre ERNENWEIN, Steven Fegan, Kirsty Feijen, Armand Fiasson, Gaëtan Fichet de Clairfontaine, Gerard Fontaine, Lott Frans, Matthias Fuessling, Stefan Funk, Stefano Gabici, Yves Gallant, Gianluca Giavitto, Luca Giunti, Dorit Glawion, Jean-Francois Glicenstein, Marie-Hélène Grondin, Sumari Hattingh, Maria Haupt, German HERMANN, Jim Hinton, Werner Hofmann, Clemens Hoischen, Tim Holch, Markus Holler, Dieter Horns, Zhi-Qiu Huang, David Huber, Mario Hörbe, Marek Jamrozy, Felix Jankowsky, Vikas Joshi, Ira JUNG, Eli Kasai, Krzysztof Katarzynski, Ulì Katz, Dmitry Khangulyan, Bruno Khelifi, Stefan Klepser, Wlodek Kluzniak, Nukri Komin, Ruslan Konno, Karl Kosack, Dmitriy Kostunin, Michael Kreter, Gašper Kukec Mezek, Anu Kundu, Giovanni Lamanna, Sebastien Le Stum, Anne Lemiere, Marianne Lemoine-Goumard, Jean-Philippe Lenain, Fabian Leuschner, Christelle Levy, Thomas Lohse, Anna Luashvili, Iryna Lypova, Jonathan Mackey, Jhilik Majumdar, Denys Malyshev, Dmitry Malyshev, Vincent Marandon, Paolo Marchegiani, Alexandre Marcowith, Arnaud Mares, Guillem Martí-Devesa, Ramin Marx, Gilles Maurin, Pieter Meintjes, Manuel Meyer, Alison Mitchell, Rafal Moderski, Alessandro Montanari, Chris Moore, Paul Morris, Emmanuel Moulin, Jacques Muller, Thomas Murach, Kaori Nakashima, Mathieu Naurois (de), Amid Nayerhoda, Hambeleleni Davids, Jacek Niemiec, Angel Noel, Paul O'Brien, Laenita Lorraine Oberholzer, Stefan Ohm, Laura Olivera-Nieto, Emma Ona-Wilhelmi (de), Michal Ostrowski, Sebastian Panny, Michael Panter, Dan Parsons, Giada Peron, Santiago Pita, Vincent Poireau, Dmitry A Prokhorov, Heike Prokoph, Gerd PUEHLHOFER, Michael Punch, Andreas Quirrenbach, Romed Rauth, Patrick Reichherzer, Anita Reimer, Olaf Reimer, Quentin Remy, Matthieu Renaud, Brian Reville, Frank Rieger, Carlo Romoli, Gavin P Rowell, Bronislaw Rudak, Hector Rueda Ricarte, Edna Ruiz Velasco, Vardan Sahakian, Simon Sailer, Heiko Salzmann, David Sanchez, Andrea Santangelo, Manami Sasaki, Johannes Schaefer, Hester Schutte, Ullrich Schwanke, Fabian Schüssler, Mohanraj Senniappan, Albert Seyffert, Jimmy N.S. Shapopi, Kleopas Shiningayamwe, Rachel Simoni, Atreyee Sinha, Helene Sol, Hugh Spackman, Andreas Specovius, Samuel Timothy Spencer, Marion Spir-Jacob, Lukasz Stawarz, Riaan Steenkamp, Christian Stegmann, Simon Steinmassl, Constantin Steppa, Lei Sun, Tadayuki Takahashi, Takaaki Tanaka, Thomas Tavernier, Andrew Taylor, Regis Terrier, Hannes Thiersen, Charles Thorpe-Morgan, Martin Tluczykont, Lenka Tomankova, Michelle Tsirou, Naomi Tsuji, Richard Tuffs, Yasunobu Uchiyama, Johann van der Walt, Christopher van Eldik, Carlo van Rensburg, Brian van Soelen, George Vasileiadis, Johannes Veh, Christo Venter, Pascal Vincent, Jacco Vink, Heinrich J. Völk, Stefan Wagner, Jason John Watson, Felix Werner, Richard White, Alicja Wierzcholska, Yu Wun Wong, Hend Mahmoud Yassin, Anke Yusafzai, Michael Zacharias, Roberta Zanin, Davit Zargaryan, Andrzej Zdziarski, Andreas Zech, Sylvia Zhu, Andreas Zmija, Samuel Zouari, Natalia Żywucka, Naurois , Mathieu, Ona-Wilhelmi , Emma, and Bony , Mathieu

Subjects
Physics, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Gamma ray, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Likelihood analysis, Energy spectrum, Cluster (physics), ddc:530, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract

37th International Cosmic Ray Conference, ICRC 2021, Berlin, online, Germany, 12 Jul 2021 - 23 Jul 2021; Proceedings of Science / International School for Advanced Studies (ICRC2021), 789 (2021). doi:10.22323/1.395.0789, Massive stellar clusters have recently been hypothesised as candidates for the acceleration of hadronic cosmic rays up to PeV energies. Previously, the H.E.S.S. Collaboration has reported about very extended $\gamma$-ray emission around Westerlund 1, a massive young stellar cluster in the Milky Way. In this contribution we present an updated analysis that employs a new analysis technique and is based on a much larger data set, allowing us to constrain better the morphology and the energy spectrum of the emission. The analysis technique used is a three-dimensional likelihood analysis, which is especially well suited for largely extended sources. The origin of the $\gamma$-ray emission will be discussed in light of multi-wavelength observations., Published by SISSA, Trieste

Published
2021
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5. Evidence of Cosmic-Ray Excess from Local Giant Molecular Clouds

Author

Giada Peron, Vardan Baghmanyan, Sabrina Casanova, Roberta Zanin, and Felix Aharonian

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Astrophysics, 01 natural sciences, Power law, Spectral line, law.invention, Hochenergie-Astrophysik Theorie - Abteilung Hinton, Telescope, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Molecular cloud, Gamma ray, Astronomy and Astrophysics, Supernova, Stars, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the analysis of the Fermi-Large Area Telescope data from six nearby giant molecular clouds (MCs) belonging to the Gould Belt and the Aquila Rift regions. The high statistical {\gamma}-ray spectra above 3 GeV well described by power laws make it possible to derive precise estimates of the cosmic-ray (CR) distribution in the MCs. The comparison of {\gamma}-ray spectra of Taurus, Orion A, and Orion B clouds with the model expected from Alpha Magnetic Spectrometer (AMS-02) CR measurements confirms these clouds as passive clouds, immersed in an AMS-02-like CR spectrum. A similar comparison of Aquila Rift, Rho Oph, and Cepheus spectra yields significant deviation in both spectral indices and absolute fluxes, which can imply an additional acceleration of CRs throughout the entire clouds. Besides, the theoretical modeling of the excess {\gamma}-ray spectrum of these clouds, assuming {\pi}0-decay interaction of CRs in the cloud, gives a considerable amount of an enhanced CR energy density and it shows a significant deviation in spectral shapes compared to the average AMS-02 CR spectrum between 30 GeV and 10 TeV. We suggest that this variation in the CR spectrum of Cepheus could be accounted for by an efficient acceleration in the shocks of winds of OB associations, while in Rho Oph, similar acceleration can be provided by multiple T-Tauri stars populated in the whole cloud. In the case of Aquila Rift, the excess in absolute CR flux could be related to an additional acceleration of CRs by supernova remnants or propagation effects in the cloud., Comment: 6 pages, 3 figures. Published in ApJL

Published
2020

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