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1. Is PKS 0625-354 another variable TeV active galactic nucleus?

Author

Halim Ashkar, Fabian Leuschner, Gilles Maurin, Riaan Steenkamp, J. F. Glicenstein, Heike Prokoph, Bruno Khelifi, Floriane Cangemi, Michael Punch, Gianluca Giavitto, Anna Luashvili, Lott Frans, Sumari Hattingh, Martin Tluczykont, Marek Jamrozy, Sabrina Einecke, Takaaki Tanaka, Iryna Lypova, Marion Spir-Jacob, Yvonne Becherini, Helene Sol, Rachel Simoni, Davit Zargaryan, Hannah Dalgleish, Jim Hinton, Gašper Kukec Mezek, Gaëtan Fichet de Clairfontaine, Axel Donath, A. W. Chen, S. Sailer, Dmitry Khangulyan, Charles Thorpe-Morgan, Andreas Zmija, Amid Nayerhoda, M. Lemoine-Goumard, Stefan Klepser, Alessandro Montanari, C. Arcaro, S. J. Fegan, Anu Kundu, B. Rudak, T. Chand, Hend Yassin, Michael Kreter, Paolo Marchegiani, Tadayuki Takahashi, Dmitriy Kostunin, Mathieu Bony, Oguzhan Anguener, Fabian Schüssler, Manuel Meyer, Markus Boettcher, Gavin Rowell, Kathrin Egberts, Maria Haupt, Victor Doroshenko, Emmanuel Moulin, Ira Jung, Brian van Soelen, Sebastian Panny, Mathieu Naurois, E. Kasai, Kirsty Feijen, Samuel Timothy Spencer, Dieter Horns, Vikas Joshi, Thomas Tavernier, Johannes Schaefer, Gerd Puehlhofer, Lei Sun, Constantin Steppa, Jacek Niemiec, Hassan Abdalla, Albert Seyffert, Olaf Reimer, Christian Stegmann, Stefan Wagner, Andreas Zech, Alexandre Marcowith, Regis Terrier, Felix Werner, Yasunobu Uchiyama, K. Nakashima, K. Bernloehr, Carlo Romoli, Hector Rueda Ricarte, Lukasz Stawarz, Frank M. Rieger, Thomas Murach, Kleopas Shiningayamwe, Clemens Hoischen, A. A. Zdziarski, Christopher van Eldik, N. Zywucka, Jaqueline Catalano, L. Mohrmann, Monica Barnard, Rafal Moderski, Heinrich J. Völk, Arnaud Mares, Ullrich Schwanke, Stefan Ohm, Thomas Bylund, Rowan Batzofin, Anita Reimer, Andreas Quirrenbach, Edna Ruiz Velasco, Johann van der Walt, Jhilik Majumdar, Guillem Marti'i-Devesa, R. Konno, Jacques Muller, Dan Parsons, Jean Damascene Mbarubucyeye, Wlodek Kluzniak, Lenka Tomankova, Stefano Gabici, Andrew Taylor, Michael Zacharias, Christo Venter, Sylvia Zhu, P. J. Meintjes, David Berge, M. Hörbe, Michael Backes, Robert Brose, V. Poireau, Jimmy N.S. Shapopi, V. Sahakian, Krzysztof Katarzynski, Brian Reville, Connor Duffy, Laenita Lorraine Oberholzer, Tim Holch, Anton Dmytriiev, M. Fuessling, Manami Sasaki, G. Vasileiadis, Catherine Boisson, Arache Djannati-Ataï, P. Reichherzer, J. Bolmont, Jason John Watson, D. Malyshev, Andrea Santangelo, Naomi Tsuji, Matthieu Renaud, Denys Malyshev, Isak Delberth Davids, G. Lamanna, James Davies, A. Fiasson, Roberta Zanin, Yves Gallant, S. Steinmassl, Sami Caroff, R. J. Tuffs, Gerard Fontaine, B. Bi, Santiago Pita, Hambeleleni Ndiyavala, Hester Schutte, Justine Devin, Mohanraj Senniappan, C. Levy, Mischa Breuhaus, Pauline Chambery, Andreas Specovius, Jean-Pierre Ernenwein, Yu Wun Wong, Johannes Veh, Vincent Marandon, Hannes Thiersen, Vardan Baghmanyan, Markus Holler, Q. Remy, Felix Jankowsky, Richard White, Felix Aharonian, Jacco Vink, Alison Mitchell, David Huber, Sabrina Casanova, Louis Du Plessis, Angel Noel, Jonathan Mackey, Anna Barnacka, C. Moore, Victor Barbosa Martins, Dorit Glawion, Carlo van Rensburg, Anne Lemiere, Tomasz Bulik, Malgorzata Curlo, Emma Ona-Wilhelmi, Samuel Zouari, Thomas Lohse, Lente Dreyer, Michal Ostrowski, J.-P. Lenain, Hugh Spackman, Stefan Funk, Alicja Wierzcholska, Ramin Marx, M. Panter, U. Katz, Faical Ait-Benkhali, G. Peron, Garret Cotter, Sébastien Le Stum, Zhiqiu Huang, D. A. Prokhorov, K. Kosack, P. T. O'Brien, Atreyee Sinha, Laura Olivera-Nieto, A. Yusafzai, Nukri Komin, Tom Armstrong, David Sanchez, Werner Hofmann, L. Giunti, Michelle Tsirou, Francois Brun, P. Vincent, Heiko Salzmann, Celine Armand, M.-H. Grondin, German Hermann, and Paul Morris

Subjects
Physics, Brightness, Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Viewing angle, Variable (computer science), symbols.namesake, symbols, Spectral energy distribution, Blazar, Doppler effect, Astrophysics::Galaxy Astrophysics
Abstract

The majority of the active galactic nuclei (AGN) detected at very-high-energies above 100 GeV belong to the class of blazars with a small angle between the jet-axis and the line-of-sight. Only about 10 percent of the gamma-ray AGN are objects with a larger viewing angle resulting in a smaller Doppler boosting of the emission. Originally, it was believed that gamma-ray emission can only be observed from blazars and those are variable in its brightness. Instead, the last years have shown that non-blazar active galaxies also show a fascinating variability behaviour which provide important new insights into the physical processes responsible for the gamma-ray production and especially for flaring events. Here, we report on the observation of gamma-ray variability of the active galaxy PKS 0625−354 detected with the H.E.S.S. telescopes in November 2018. The classification of PKS 0625−354 is a still matter of debate. The H.E.S.S. measurements were performed as part of a flux observing program and showed in the first night of the observation a detection of the object with > 5σ. A denser observation campaign followed for the next nine nights resulting in a decrease of the gamma-ray flux. Those observations were accompanied with Swift in the X-ray and UV/optical band allowing for the reconstruction of a multi-band broad-band spectral energy distribution. We will discuss the implications of the gamma-ray variability of the object.

Published
2021

2. Search for dark matter annihilation towards the inner Milky Way halo with the H.E.S.S. Inner Galaxy Survey

Author

Clemens Hoischen, A. A. Zdziarski, Robert Brose, Johann van der Walt, Halim Ashkar, Fabian Leuschner, Stefan Ohm, L. Giunti, Albert Seyffert, Davit Zargaryan, Stefan Klepser, Alessandro Montanari, K. Nakashima, Gaëtan Fichet de Clairfontaine, Sabrina Einecke, Axel Donath, A. W. Chen, Iryna Lypova, K. Bernloehr, Heinrich J. Völk, Yvonne Becherini, Stefano Gabici, Michelle Tsirou, Anna Luashvili, Vikas Joshi, J. Bolmont, Fabian Schüssler, M.-H. Grondin, Emmanuel Moulin, Andreas Specovius, Kleopas Shiningayamwe, Anne Lemiere, B. Rudak, Lott Frans, Michael Punch, Edna Ruiz Velasco, Sylvia Zhu, P. J. Meintjes, David Berge, Michael Backes, Matthieu Renaud, German Hermann, Paul Morris, Kathrin Egberts, Constantin Steppa, Tadayuki Takahashi, Laenita Lorraine Oberholzer, Tim Holch, Lukasz Stawarz, Louis Du Plessis, Naomi Tsuji, V. Poireau, Jimmy N.S. Shapopi, Victor Doroshenko, Yu Wun Wong, Emma Ona-Wilhelmi, Riaan Steenkamp, E. Kasai, G. Lamanna, Ullrich Schwanke, Gerard Fontaine, Jim Hinton, Victor Barbosa Martins, Thomas Lohse, Frank M. Rieger, Hester Schutte, Carlo van Rensburg, Francois Brun, P. Vincent, Heiko Salzmann, Mathieu Bony, Oguzhan Anguener, Kirsty Feijen, S. Sailer, Dmitry Khangulyan, Charles Thorpe-Morgan, Ramin Marx, Dmitriy Kostunin, M. Panter, U. Katz, Jean Damascene Mbarubucyeye, Wlodek Kluzniak, Jaqueline Catalano, R. Konno, Hector Rueda Ricarte, T. Chand, Samuel Zouari, P. T. O'Brien, M. Hörbe, Celine Armand, Andreas Quirrenbach, Guillem Marti'i-Devesa, Faical Ait-Benkhali, Andrew Taylor, G. Vasileiadis, Vincent Marandon, Brian van Soelen, Marek Jamrozy, Hannes Thiersen, Dieter Horns, Hassan Abdalla, Thomas Bylund, Rowan Batzofin, Sébastien Le Stum, Thomas Tavernier, Gilles Maurin, Floriane Cangemi, Helene Sol, Christian Stegmann, Jacques Muller, Vardan Baghmanyan, Johannes Schaefer, J. F. Glicenstein, Anu Kundu, Stefan Wagner, Andreas Zech, Yasunobu Uchiyama, Monica Barnard, L. Mohrmann, Arache Djannati-Ataï, C. Levy, Atreyee Sinha, Bruno Khelifi, Michal Ostrowski, J.-P. Lenain, Hugh Spackman, Michael Zacharias, Regis Terrier, Hannah Dalgleish, P. Reichherzer, Andreas Zmija, Gianluca Giavitto, Jacek Niemiec, M. Lemoine-Goumard, Paolo Marchegiani, Markus Holler, Carlo Romoli, Isak Delberth Davids, Stefan Funk, Alicja Wierzcholska, Olaf Reimer, Q. Remy, Felix Jankowsky, Michael Kreter, Anna Barnacka, Brian Reville, Connor Duffy, A. Fiasson, Roberta Zanin, Thomas Murach, Heike Prokoph, James Davies, Sumari Hattingh, Felix Aharonian, Richard White, Angel Noel, M. Fuessling, R. J. Tuffs, B. Bi, Christo Venter, Takaaki Tanaka, D. Malyshev, Jonathan Mackey, Jacco Vink, Ira Jung, Sebastian Panny, Alison Mitchell, Anita Reimer, David Huber, Sabrina Casanova, Marion Spir-Jacob, Mischa Breuhaus, Pauline Chambery, Gerd Puehlhofer, C. Arcaro, C. Moore, Jhilik Majumdar, Lei Sun, Santiago Pita, Hambeleleni Ndiyavala, S. Steinmassl, Sami Caroff, Anton Dmytriiev, Dorit Glawion, G. Peron, Garret Cotter, Alexandre Marcowith, Felix Werner, Amid Nayerhoda, Manami Sasaki, Tomasz Bulik, Zhiqiu Huang, Malgorzata Curlo, Maria Haupt, Andrea Santangelo, Arnaud Mares, Lente Dreyer, D. A. Prokhorov, K. Kosack, V. Sahakian, Gavin Rowell, Jean-Pierre Ernenwein, N. Zywucka, Denys Malyshev, Markus Boettcher, Yves Gallant, Christopher van Eldik, Rafal Moderski, Johannes Veh, Samuel Timothy Spencer, Mohanraj Senniappan, Rachel Simoni, Dan Parsons, Krzysztof Katarzynski, Catherine Boisson, Justine Devin, Lenka Tomankova, Martin Tluczykont, Gašper Kukec Mezek, Hend Yassin, Manuel Meyer, Mathieu Naurois, Jason John Watson, S. J. Fegan, Nukri Komin, Tom Armstrong, David Sanchez, Werner Hofmann, Laura Olivera-Nieto, and A. Yusafzai

Subjects
Physics, Annihilation, WIMP, Milky Way, Weakly interacting massive particles, media_common.quotation_subject, Dark matter, Astrophysics::Cosmology and Extragalactic Astrophysics, Halo, Astrophysics, Galaxy, Universe, media_common
Abstract

The presence of dark matter (DM) is suggested by a wealth of astrophysical and cosmological measurements. However, its underlying nature is yet unknown. Among the most promising candidates are weakly interacting massive particles (WIMPs): particles with mass and coupling strength at the electroweak scale and thermally produced in the early universe have a present relic density consistent with that observed today. WIMP self-annihilation would produce Standard Model particles including gamma-rays, which have been long-time recognized as a prime messenger to indirectly detect dark matter signals. The centre of the Milky Way is predicted as the brightest source of DM annihilations. The H.E.S.S. collaboration is currently performing a survey of the inner region of the Milky Way, the Inner Galaxy Survey (IGS), intended to achieve the best sensitivity to faint and diffuse emissions in a region of several degrees around the Galactic Centre. We analyzed 2014-2020 observations taken with the five-telescope array to search for a DM annihilation signal. With the current dataset of about 550 hours, we found no significant excess and therefore derived strong constraints on the velocity-weighted annihilation cross-section. TeV thermal WIMPs can be probed in different annihilation channels.

Published
2021

3. Detection of very-high-energy γ -ray emission from the colliding wind binary η Car with H.E.S.S

Author

E. O. Angüner, Ramin Marx, M. Panter, U. Katz, G. Heinzelmann, Iryna Lypova, S. Nakashima, Yvonne Becherini, G. Martí-Devesa, Stefan Klepser, H. Yoneda, A. Fiasson, L. Giunti, P. deWilt, J. King, R. Adam, I. Jung-Richardt, James Davies, F. Eichhorn, Michael Punch, Maria Haupt, R. J. Tuffs, Michal Ostrowski, J.-P. Lenain, Stefan Ohm, Łukasz Stawarz, J. F. Glicenstein, Frank M. Rieger, Markus Holler, Michelle Tsirou, C. Levy, S. Pita, S. Colafrancesco, L. Rinchiuso, Q. Remy, Felix Jankowsky, J. Zorn, M.-H. Grondin, Mischa Breuhaus, C. Arcaro, Stefano Gabici, F. Niederwanger, Jacco Vink, Sabrina Casanova, Halim Ashkar, M. Curyło, Stefan Funk, Alicja Wierzcholska, Gavin Rowell, M. Bryan, Felix Aharonian, N. Shafi, R. D. Parsons, H. Ndiyavala, B. van Soelen, B. Rudak, Dmitriy Kostunin, K. Nakashima, Nu. Komin, Natalia Żywucka, M. de Naurois, T. Chand, Jhilik Majumdar, L. Oakes, A. Lemière, Heinrich J. Völk, M. Renaud, R. Rauth, Axel Donath, A. W. Chen, M. Büchele, S. Eschbach, M. Barnard, Marek Jamrozy, J. Bolmont, Gianluca Giavitto, K. Bernlöhr, Helene Sol, V. Poireau, H. Odaka, M. Füßling, Jacek Niemiec, Rafal Moderski, C. Perennes, K. Egberts, Dieter Horns, Olaf Reimer, M. Lemoine-Goumard, J. Dyks, Ruizhi Yang, Francois Brun, Reinhard Schlickeiser, Zorawar Wadiasingh, M. Böttcher, Michael Kreter, S. Chandra, Paolo Marchegiani, P. Vincent, S. J. Fegan, A. Djannati-Ataï, V. Barbosa Martins, S. Raab, L. Dirson, F. Gaté, Kirsty Feijen, S. Bonnefoy, Constantin Steppa, Alexandre Marcowith, M. Zacharias, Rachel Simoni, Masanori Arakawa, Celine Armand, Thomas Murach, Joachim Hahn, T. Vuillaume, A. Schulz, Clemens Hoischen, A. A. Zdziarski, Ullrich Schwanke, V. Joshi, V. Sahakian, A. Carosi, F. Werner, F. Ait Benkhali, E. de Oña Wilhelmi, Anton Dmytriiev, Isak Delberth Davids, S. Schwemmer, Arnaud Mares, Andrea Santangelo, Jim Hinton, Roberta Zanin, C. Trichard, S. Sailer, Dmitry Khangulyan, P. J. Meintjes, Tom Armstrong, Matteo Cerruti, D. A. Sanchez, M. Seglar-Arroyo, P.-O. Petrucci, Johan Bregeon, R. J. White, J. Devin, F. Schüssler, M. Scalici, A. Priyana Noel, Domenico Tiziani, D. Malyshev, Tadayuki Takahashi, A.M. Taylor, Werner Hofmann, Michael Backes, Jonathan Mackey, Victor Doroshenko, Gilles Henri, Heike Prokoph, C. Moore, Q. Piel, Dorit Glawion, Tim Holch, E. Moulin, Tomasz Bulik, S. Caroff, D. Huber, Marion Spir-Jacob, G. Maurin, H. Iwasaki, A.S. Seyffert, Naomi Tsuji, D. Jankowsky, Gerard Fontaine, M. Katsuragawa, Andreas Quirrenbach, Hester Schutte, Riaan Steenkamp, Andreas Specovius, Christian Stegmann, Stefan Wagner, Yasunobu Uchiyama, L. Mohrmann, C. van Rensburg, Misao Sasaki, D. J. van der Walt, M. Hörbe, T. Tavernier, E. Leser, P. T. O'Brien, B. Khélifi, G. Hermann, Regis Terrier, Carlo Romoli, Christo Venter, Y. A. Gallant, Atreyee Sinha, C. van Eldik, A. Zech, M. Mohamed, Garret Cotter, D. A. Prokhorov, K. Kosack, B. Peyaud, G. Pühlhofer, A. Reimer, Pierre Brun, Jean-Pierre Ernenwein, Johannes Veh, R. Blackwell, E. Ruiz-Velasco, G. Emery, S. Saito, Thomas Bylund, M. Tluczykont, Armelle Jardin-Blicq, Jacques Muller, Samuel Timothy Spencer, H. Abdalla, M. A. Kastendieck, G. Vasileiadis, Włodek Kluźniak, Krzysztof Katarzynski, Catherine Boisson, Christoph Deil, Mohanraj Senniappan, D. Berge, Paul J. Morris, Kleopas Shiningayamwe, Lenka Tomankova, Jason John Watson, V. Marandon, D. Gottschall, Thomas Lohse, G. Lamanna, Alexander von Humboldt Foundation, Southern California Earthquake Center, EGI Foundation, Science and Technology Facilities Council (UK), Australian Research Council, German Research Foundation, Japan Society for the Promotion of Science, University of Amsterdam, Federal Ministry of Education and Research (Germany), Austrian Science Fund, Knut and Alice Wallenberg Foundation, Max Planck Society, National Science Centre (Poland), Centre National de la Recherche Scientifique (France), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Helmholtz Association, National Commission on Research Science and Technology (Namibia), University of Namibia, Federal Ministry of Education, Science and Research (Austria), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 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), 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 Univers et Théories (LUTH (UMR_8102)), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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 de Paris (UP), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), H.E.S.S., Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, H.E.S.S. Collaboration, Faculty of Science, High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
individual: η CarStars: Wolf-Rayet [Stars], Photon, stars: individual: η Car, Astrophysics::High Energy Astrophysical Phenomena, Flux, Cosmic ray, Astrophysics, 01 natural sciences, cosmic rays, 0103 physical sciences, individual: η Car [stars], High Energy Stereoscopic System, 010303 astronomy & astrophysics, Cosmic rays, Colliding-wind binary, Astroparticle physics, Physics, Spectral index, non-thermal [Radiation mechanisms], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Binaries], 010308 nuclear & particles physics, Astronomy and Astrophysics, radiation mechanisms: non-thermal, Wolf-Rayet [stars], binaries: general, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], astroparticle physics, ddc:520, HESS - Abteilung Hinton, stars: Wolf-Rayet, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stars: individual: η CarStars: Wolf-Rayet, Noise (radio)
Abstract

Aims. Colliding wind binary systems have long been suspected to be high-energy (HE; 100 MeV < E < 100 GeV) {\gamma}-ray emitters. {\eta} Car is the most prominent member of this object class and is confirmed to emit phase-locked HE {\gamma} rays from hundreds of MeV to ~100 GeV energies. This work aims to search for and characterise the very-high-energy (VHE; E >100 GeV) {\gamma}-ray emission from {\eta} Car around the last periastron passage in 2014 with the ground-based High Energy Stereoscopic System (H.E.S.S.). Methods. The region around {\eta} Car was observed with H.E.S.S. between orbital phase p = 0.78 - 1.10, with a closer sampling at p {\approx} 0.95 and p {\approx} 1.10 (assuming a period of 2023 days). Optimised hardware settings as well as adjustments to the data reduction, reconstruction, and signal selection were needed to suppress and take into account the strong, extended, and inhomogeneous night sky background (NSB) in the {\eta} Car field of view. Tailored run-wise Monte-Carlo simulations (RWS) were required to accurately treat the additional noise from NSB photons in the instrument response functions. Results. H.E.S.S. detected VHE {\gamma}-ray emission from the direction of {\eta} Car shortly before and after the minimum in the X-ray light-curve close to periastron. Using the point spread function provided by RWS, the reconstructed signal is point-like and the spectrum is best described by a power law. The overall flux and spectral index in VHE {\gamma} rays agree within statistical and systematic errors before and after periastron. The {\gamma}-ray spectrum extends up to at least ~400 GeV. This implies a maximum magnetic field in a leptonic scenario in the emission region of 0.5 Gauss. No indication for phase-locked flux variations is detected in the H.E.S.S. data., Comment: 9 pages, 4 figures, 3 tables, in press with A&A

Published
2020

4. A radiation transfer model for the Milky Way: I. Radiation fields and application to high-energy astrophysics★

Author

R. J. Tuffs, M. T. Rushton, Ruizhi Yang, Felix Aharonian, Giovanni Natale, and Cristina Popescu

Subjects
Physics, Galactic astronomy, Opacity, 010308 nuclear & particles physics, High-energy astronomy, Astrophysics::High Energy Astrophysical Phenomena, Milky Way, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Cosmic ray, F500, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Oort constants
Abstract

We present a solution for the ultraviolet (UV) - submillimeter (submm) interstellar radiation fields (ISRFs) of the Milky Way, derived from modelling COBE, IRAS and Planck maps of the all-sky emission in the near-, mid-, far-infrared and submm.The analysis uses the axisymmetric radiative transfer (RT) model that we have previously implemented to model the panchromatic spectral energy distributions (SEDs) of star forming galaxies in the nearby universe, but with a new methodology allowing for optimisation of the radial and vertical geometry of stellar emissivity and dust opacity, as deduced from the highly resolved emission seen from the vantage point of the Sun. As such, this is the first self-consistent model of the broad-band continuum emission from the Milky Way. In this paper, we present model predictions for the spatially integrated SED of the Milky Way as seen from the Sun, showing good agreement with the data, and give a detailed description of the solutions for the distribution of ISRFs, as well as their physical origin, throughout the volume of the galaxy. We explore how the spatial and spectral distribution of our new predictions for the ISRF in the Milky Way affects the amplitude and spectral distribution of the gamma-rays produced via Inverse Compton scattering for cosmic ray electrons situated at different positions in the galaxy, as well as the attenuation of the gamma-rays due to interactions of the gamma-ray photons with photons of the ISRF. We also compare and contrast our solutions for the ISRF with those incorporated in the GALPROP package used for modelling the high energy emission from cosmic rays in the Milky Way., 23 pages, accepted for publication in MNRAS

Published
2017

5. Combined Dark Matter searches towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, HESS, MAGIC and VERITAS

Author

Dirk Lennarz, Luis Villaseñor, Gernot Maier, Anne Lemiere, Daniel Rosa-Gonzalez, Samuel Timothy Spencer, Wystan Benbow, Victor Barbosa Martins, Raul Prado, Arache Djannati-Ataï, Regis Terrier, Dan Parsons, Francisco Salesa Greus, Dmitriy Kostunin, Joshua Wood, Carlo Romoli, César Alvarez, Carlo van Rensburg, Massimo Capasso, Sajan Kumar, P. Reichherzer, Anton Dmytriiev, Stefan Ohm, Chiara Giuri, Brian van Soelen, G. Peron, Christian Stegmann, Emma Ona-Wilhelmi, S. J. Fegan, Alison Peisker, Hawc, Garret Cotter, Gary Gillanders, Zhiqiu Huang, Krzysztof Katarzynski, Filiberto Hueyotl-Zahuantitla, Ian Herzog, D. A. Prokhorov, K. Kosack, Halim Ashkar, Fabian Leuschner, Manami Sasaki, Michael Schneider, Joe Lundeen, Markus Boettcher, Brian Humensky, Isak Delberth Davids, A. Fiasson, Stefan Wagner, Andreas Zech, Yasunobu Uchiyama, David Kieda, Michael DuVernois, Albert Seyffert, Gianluca Giavitto, Qi Feng, Andreas Specovius, Andrew James Smith, Catherine Boisson, L. Mohrmann, Roberta Zanin, Marek Jamrozy, Tomás Capistrán Rojas, K. Nakashima, Jamie Holder, Hao Zhou, Thomas Lohse, Mireia Nievas-Rosillo, Samuel Zouari, Ira Jung, Sebastian Panny, K. Bernloehr, Deivid Ribeiro, Andrea Santangelo, Kristi Engel, Josefa Becerra Gonzalez, Thomas Tavernier, Ke Fang, Rishi Babu, Yu Wun Wong, Gerd J. Kunde, Jean-Pierre Ernenwein, Henrike Fleischhack, P. T. O'Brien, Clemens Hoischen, A. A. Zdziarski, Kelly Malone, Helene Sol, Markus Holler, Manel Errando, Atreyee Sinha, Francois Brun, Heinrich J. Völk, Sumari Hattingh, Kirsten Tollefson, Johann van der Walt, Q. Remy, Felix Jankowsky, Samridha Kunwar, Johannes Veh, M. Fuessling, P. Vincent, Harm Schoorlemmer, Stefano Gabici, Miguel Mostafa, Tyler Williamson, Jacek Niemiec, Michal Ostrowski, J.-P. Lenain, Israel Martinez Castellanos, Felix Aharonian, Tadayuki Takahashi, Gerd Puehlhofer, Lei Sun, Jesús Martínez-Castro, Pooja Surajbali, Andrés Sandoval, Hugh Spackman, Takaaki Tanaka, Segev BenZvi, Alexandre Marcowith, Felix Werner, Olaf Reimer, Vincent Marandon, Alberto Carramiñana, S. Steinmassl, Mary Kertzman, Hannes Thiersen, Victor Doroshenko, Michael Backes, Hannah Jhee, G. Lamanna, Marcos Santander, Angel Noel, W. Jin, Gus Sinnis, B. Rudak, Alasdair E. Gent, Kathrin Egberts, Jonathan Mackey, Fernando Ureña-Mena, Paolo Marchegiani, Sonal Ramesh Patel, Laenita Lorraine Oberholzer, Tim Holch, Sami Caroff, Heiko Salzmann, E. Kasai, Alison Mitchell, Gregory Foote, Nukri Komin, Tom Armstrong, Michelle Hui, Ruo-Yu Shang, Binita Hona, Raquel Diaz Hernandez, Vardan Baghmanyan, Celine Armand, Alejandro Lara, David Berley, Hector Rueda Ricarte, Nissim Illich Fraija, Naomi Tsuji, Gaurang Yodh, Stefan Funk, Alicja Wierzcholska, Conor McGrath, Gerard Fontaine, C. Moore, Vikas Joshi, Dorit Glawion, T. Chand, M. U. Nisa, M.-H. Grondin, Arnaud Mares, David Sanchez, Ernesto Belmont-Moreno, Thomas Murach, Eucario Gonzalo Pérez Pérez, Paul Reynolds, Ignacio Taboada, Xiaojie Wang, Lucy Fortson, Martin Tluczykont, Thomas Brian Humensky, Juan de Dios Álvarez Romero, Robert Ellsworth, Hester Schutte, Justine Devin, Constantin Steppa, Richard White, Rachel Simoni, Karen S. Caballero Mora, Elisa Pueschel, Jason Fan, Tomasz Bulik, Lukas Nellen, Malgorzata Curlo, Lente Dreyer, J. Patrick Harding, Gilles Maurin, Humberto Martínez Huerta, Riaan Steenkamp, Arnulfo Zepeda, Johannes Schaefer, Werner Hofmann, Jim Hinton, Michael Punch, S. Sailer, Dmitry Khangulyan, Sergio Hernández Cadena, Charles Thorpe-Morgan, M. Hörbe, Stephan O'Brien, Ramin Marx, John L. Quinn, J. F. Glicenstein, V. Sahakian, M. Panter, Mora Durocher, U. Katz, Jacco Vink, Umberto Cotti, Tobias Kleiner, Petra Hüntemeyer, David Huber, Ullrich Schwanke, Diego Garcia Aguilar, Vladimir Vassiliev, Oscar Martinez, J. Bolmont, Cederik León de León, Brian Fick, Laura Olivera-Nieto, A. Yusafzai, David Hanna, James Buckley, Lorenzo Diaz, Yves Gallant, Guillermo García-Torales, Arun Babu Kollamparambil, James Ryan, Kayla Farrell, Sabrina Casanova, Bruno Khelifi, María Catalina Espinoza Hernández, Jorge Antonio Morales Soto, Mateo Fernandez Alonso, Matthew Lundy, Faical Ait-Benkhali, Jean Damascene Mbarubucyeye, Wlodek Kluzniak, Jorge Luis Flores, Ibrahim Torres, Jordan A. Goodman, Anita Reimer, Adam Otte, Eduardo Moreno Barbosa, M. J. Lang, Frank M. Rieger, Elijah Willox, Colin Adams, Pedro Miranda-Romagnoli, Louis Du Plessis, Andrea Albert, Orel Gueta, Anna Barnacka, Brenda Dingus, Gašper Kukec Mezek, Hazal Goksu, Jorge Cotzomi, William H. Lee, Ruben Alfaro, Glenn Sembroski, David A. Williams, Eduardo de la Fuente, Anu Kundu, Dezhi Huang, Brian Reville, Connor Duffy, Edna Ruiz-Velasco, Anna Luashvili, Alisha Chromey, Konstantin Pfrang, L. Giunti, Philip Kaaret, Maria Magdalena González, Olivier Hervet, Hermes Leon Vargas, Sébastien Le Stum, Amanda Weinstein, Aryeh Brill, James Davies, Ken Ragan, Santiago Pita, Juan Carlos Arteaga Velazquez, Jason Lee, Sabrina Einecke, Lukasz Stawarz, Iryna Lypova, Julie McEnery, Sara Coutiño de Leon, Dieter Horns, R. J. Tuffs, Christo Venter, Meghan Tanner, Monica Barnard, B. Bi, Yvonne Becherini, Colas Rivière, Iftach Sadeh, Lott Frans, Mischa Breuhaus, Pauline Chambery, C. Levy, Jose Luis García-Luna, Michelle Tsirou, D. Malyshev, Ramiro Torres Escobedo, Hassan Abdalla, Hambeleleni Ndiyavala, Chang Dong Rho, Jhilik Majumdar, Martin Pohl, Mathieu Bony, Oguzhan Anguener, Hend Yassin, Gwenael Giacinti, Manuel Meyer, Arturo Iriarte, John Matthews, Kirsty Feijen, Ahron S. Barber, Floriane Cangemi, Fernando Garfias, R. A. Ong, Thomas Weisgarber, Thomas Bylund, Gilgamesh Luis-Raya, Rowan Batzofin, Mathieu Naurois, Jacques Muller, Avery Archer, Andreas Quirrenbach, Anushka Udara Abeysekara, José Serna-Franco, Hugo Alberto Ayala Solares, Davit Zargaryan, Rubén López-Coto, Reshmi Mukherjee, Andreas Zmija, Guillem Marti'i-Devesa, Sameer Patel, M. Lemoine-Goumard, Roberto Noriega-Papaqui, Gaëtan Fichet de Clairfontaine, Axel Donath, A. W. Chen, Michael Kreter, Yunior Pérez Araujo, Anna Lia Longinotti, Michael Zacharias, Kleopas Shiningayamwe, Robert Brose, Fabian Schüssler, Emmanuel Moulin, Patrick Moriarty, Edna Ruiz Velasco, Michael Newbold, Oscar Chaparro-Amaro, J. T. Linnemann, Lenka Tomankova, Jodi Christiansen, Jaqueline Catalano, Ian James Watson, R. Konno, Andrew Taylor, C. Arcaro, Jason John Watson, Gavin Rowell, Daniel Omar Avila Rojas, Denys Malyshev, Emmet Roache, Rhiannon Turner, Chad Brisbois, Mohanraj Senniappan, José Roberto Angeles Camacho, Daniel Nieto, V. Poireau, Jimmy N.S. Shapopi, G. Vasileiadis, Hannah Dalgleish, donggeun tak, Juan Carlos Díaz Vélez, Armelle Jardin-Blicq, N. Zywucka, Abe Falcone, Nicola Omodei, Matthieu Renaud, German Hermann, Paul Morris, Maria Haupt, Stefan Klepser, Christopher van Eldik, Rafal Moderski, Alessandro Montanari, Amy Furniss, Sylvia Zhu, P. J. Meintjes, David Berge, Jose Andres Garcia-Gonzalez, Humberto Ibarguen Salazar, Wayne Robert Springer, Heike Prokoph, Marion Spir-Jacob, Amid Nayerhoda, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Annecy de Physique des Particules (LAPP), Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS

Subjects
Cherenkov detector, air, Cherenkov counter: water, Physics beyond the Standard Model, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, satellite, FOS: Physical sciences, IACT, Astrophysics, 01 natural sciences, GLAST, dark matter, law.invention, law, HESS, 0103 physical sciences, 010306 general physics, Cherenkov radiation, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Annihilation, 010308 nuclear & particles physics, background, new physics, imaging, sensitivity, MAGIC, Galaxy, Automatic Keywords, annihilation, VERITAS, galaxy, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], statistical, HAWC, Fermi Gamma-ray Space Telescope
Abstract

36th International Cosmic Ray Conference, ICRC2019, Madison, USA, 24 Jul 2019 - 1 Aug 2019; 9 pages (2019)., The search for Dark Matter (DM) has great potential to reveal physics beyond the Standard Model. As such, searches for evidence of DM particles are being carried out using a wide range of techniques, such as direct searches for DM particles, searches for DM produced with colliders, and indirect searches for the Standard Model annihilation products of DM. Dwarf spheroidal galaxies (dSphs) are excellent targets for indirect Dark Matter searches due to their relatively high DM content and negligible expected astrophysical background. A collaboration was formed to maximise the sensitivity of DM searches towards dSphs by combining for the first time dSph data from three imaging air Cherenkov telescope (IACT) arrays: HESS, MAGIC, and VERITAS; the Fermi-LAT satellite, and the water Cherenkov detector HAWC. Due to the diverse nature of the instruments involved, each experiment will analyse their individual datasets from multiple targets and then the results will be combined at the likelihood level. For consistency of the likelihoods across the five experiments, a common approach is used to treat the astrophysical factor (J-Factor) for each target and an agreed set of annihilation channels are considered. We also agree on a common statistical approach and treatment of instrumental systematic uncertainties. The results are presented in terms of constraints on the velocity-weighted cross section for DM self-annihilation as a function of the DM particle mass.

Published
2019
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6. Publisher Correction: Resolving acceleration to very high energies along the jet of Centaurus A

Author

T. Bulik, Stefan Klepser, Axel Donath, A. W. Chen, Seb. Funk, Nukri Komin, Matteo Cerruti, D. Berge, F. Schüssler, Florian Gaté, D. Gottschall, Anne Lemiere, Iryna Lypova, Yvonne Becherini, Kleopas Shiningayamwe, S. Raab, Kirsty Feijen, Michael Punch, E. O. Angüner, Werner Hofmann, Riaan Steenkamp, Gilles Fontaine, H. Iwasaki, M. Seglar-Arroyo, A. Carosi, K. Egberts, S. Nakashima, D. Khangulyan, W. Kluźniak, Michael Backes, Rachel Simoni, Thomas Lohse, D.A. Prokhorov, M. Kraus, D. Jankowsky, A. S. Seyffert, Francois Brun, Masanori Arakawa, R. Blackwell, Ramin Marx, M. Panter, U. Katz, Markus Böttcher, Thomas Bylund, H. Yoneda, L. B. Oakes, Tim Holch, C. Mariaud, Dieter Horns, Jim Hinton, M. Füßling, Jacques Muller, J. Bregeon, Gavin Rowell, Clemens Hoischen, A. A. Zdziarski, F. Ait Benkhali, Anton Dmytriiev, Naomi Tsuji, S. Schwemmer, J. Zorn, M. Bryan, Celine Armand, M. Büchele, H. M. Schutte, M. Lemoine-Goumard, C. Perennes, Edna Ruiz-Velasco, G. Martí-Devesa, Gilles Henri, Q. Piel, Dmitriy Kostunin, Stefan Ohm, Andrea Santangelo, M.-H. Grondin, G. Emery, G. Lamanna, Jacek Niemiec, R. Rauth, D. J. van der Walt, Zorawar Wadiasingh, Olaf Reimer, J. Lau, P. T. O'Brien, M. Katsuragawa, Arnaud Mares, S. J. Fegan, A. Djannati-Ataï, S. Pita, Stefano Gabici, Thomas Tavernier, Monica Barnard, C. Boisson, J. Dyks, G. Heinzelmann, P.-O. Petrucci, R. D. Parsons, Thomas Murach, I. Jung-Richardt, Sami Caroff, J. Vink, Gianluca Giavitto, J.-P. Lenain, Regis Terrier, Krzysztof Katarzynski, M. Capasso, T. Chand, V. Barbosa Martins, Jonathan Mackey, Markus Holler, Q. Remy, E. Leser, Andreas Quirrenbach, Felix Jankowsky, Armelle Jardin-Blicq, B. Peyaud, Shun Saito, M. Ostrowski, N. Shafi, Pierre Brun, Natalia Żywucka, Felix Aharonian, U. Schwanke, B. Khélifi, G. Hermann, J. Bolmont, Alicja Wierzcholska, Jean-Pierre Ernenwein, C. Arcaro, R. White, Atreyee Sinha, V. Marandon, H. Odaka, C. van Eldik, Christian Stegmann, Domenico Tiziani, Alison Mitchell, S. Eschbach, Dorit Glawion, Johannes Veh, M. de Naurois, E. Moulin, Reinhard Schlickeiser, L. Mohrmann, C. van Rensburg, P. deWilt, M. Tluczykont, J. King, Misao Sasaki, S. Chandra, V. Sahakian, Y. A. Gallant, T. Vuillaume, Jhilik Majumdar, Justine Devin, K. Kosack, Pascal Vincent, Joachim Hahn, M. Zacharias, Konrad Bernlöhr, L. Dirson, G. Pühlhofer, Michelle Tsirou, R. J. Tuffs, Ł. Stawarz, Ruizhi Yang, H. Prokoph, Christoph Deil, J. F. Glicenstein, A. Priyana Noel, L. Rinchiuso, D. Huber, A. Reimer, Mohanraj Senniappan, Mischa Breuhaus, S. Bonnefoy, Constantin Steppa, A. Schulz, I. Oya, E. de Oña Wilhelmi, Isak Delberth Davids, A. Fiasson, V. Poireau, Roberta Zanin, H. Abdalla, M. A. Kastendieck, S. J. Wagner, G. Vasileiadis, M. Mohamed, Marek Jamrozy, Tadayuki Takahashi, Victor Doroshenko, D. Malyshev, Helene Sol, Christo Venter, R. Moderski, A. Zech, David Sánchez, Andreas Specovius, Christopher J. Moore, Y. Uchiyama, L. O'c. Drury, A.M. Taylor, A. Marcowith, Hambeleleni Ndiyavala, Heinrich J. Völk, M. Renaud, R. Adam, Gilles Maurin, Halim Ashkar, B. van Soelen, B. Rudak, Frank M. Rieger, F. Voisin, C. Levy, S. Colafrancesco, F. Niederwanger, Sabrina Casanova, M. Curyło, C. Trichard, P. J. Meintjes, A. Ziegler, Maria Haupt, C. Romoli, and Marion Spir-Jacob

Subjects
Physics, Acceleration, Jet (fluid), Multidisciplinary, Centaurus A, Astrophysics
Published
2020

7. The consequence of a new ISRF model of the Milky Way on predictions for diffuse gamma-ray emission

Author

Olaf Reimer, Felix Niederwanger, R. J. Tuffs, Ralf Kissmann, Andrew W. Strong, and Cristina Popescu

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), F990, 010308 nuclear & particles physics, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, Galactic Center, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Electron, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, Galactic plane, 01 natural sciences, Positron, 13. Climate action, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We investigate the impact of the recently published ISRF model of the Milky Way by Popescu et al. on the CR electrons and positrons in the context of cosmic-ray transport modelling. We also study predictions for diffuse Galactic gamma radiation and underline the importance of the increased ISRF intensities.We use the PICARD code for solving the CR transport equation to obtain predictions based on Galactic cosmic-ray electron fluxes. We show that the new ISRF yields gamma-ray intensity increases, most particular at the Galactic Center and in the Galactic Plane. The impact is largest at energies around 220 GeV., Comment: 20 pages, 15 figures

Published
2018
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8. Herschel-ATLAS: multi-wavelength SEDs and physical properties of 250 μm selected galaxies atz< 0.5

Author

E. Ibar, A. Verma, Kate Rowlands, Pasquale Temi, James Dunlop, David Bonfield, Maarten Baes, Loretta Dunne, G. de Zotti, Stéphane Charlot, E. da Cunha, D. L. Clements, Rob Ivison, Simon P. Driver, Matt J. Jarvis, Steve Eales, D. J. B. Smith, N. Bourne, H. L. Gomez, B. F. Madore, Mark Seibert, R. J. Tuffs, P. van der Werf, E. E. Rigby, Douglas Scott, Simon Dye, L. Kelvin, Aaron S. G. Robotham, S. J. Maddox, A. Dariush, S. Buttiglione, Jacopo Fritz, Asantha Cooray, E. Andrae, M. Pohlen, Antonio Cava, M. Symeonidis, Robbie Richard Auld, Nick Seymour, Cristina Popescu, and R. Hopwood

Subjects
Physics, COSMIC cancer database, 010308 nuclear & particles physics, Star formation, Infrared, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), 01 natural sciences, Galaxy, Redshift, Luminosity, Photometry (optics), Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present a pan-chromatic analysis of an unprecedented sample of 1402 250 micron-selected galaxies at z < 0.5 (mean z = 0.24) from the Herschel-ATLAS survey. We complement our Herschel 100-500 micron data with UV-K-band photometry from the Galaxy And Mass Assembly (GAMA) survey and apply the MAGPHYS energy-balance technique to produce pan-chromatic SEDs for a representative sample of 250 micron selected galaxies spanning the most recent 5 Gyr of cosmic history. We derive estimates of physical parameters, including star formation rates, stellar masses, dust masses and infrared luminosities. The typical H-ATLAS galaxy at z < 0.5 has a far-infrared luminosity in the range 10^10 - 10^12 Lsolar (SFR: 1-50 Msolar/yr) thus is broadly representative of normal star forming galaxies over this redshift range. We show that 250 micron-selected galaxies contain a larger mass of dust at a given infra-red luminosity or star formation rate than previous samples selected at 60 micron from IRAS. We derive typical SEDs for H-ATLAS galaxies, and show that the emergent SED shape is most sensitive to specific star formation rate. The optical-UV SEDs also become more reddened due to dust at higher redshifts. Our template SEDs are significantly cooler than existing infra-red templates. They may therefore be most appropriate for inferring total IR luminosities from moderate redshift submillimetre selected samples and for inclusion in models of the lower redshift submillimetre galaxy populations.

Published
2012

9. Herschel-ATLAS/GAMA: spatial clustering of low-redshift submm galaxies

Author

A. Dariush, Steve Eales, Scott M. Croom, Matt J. Jarvis, G. Rodighiero, Maarten Baes, G. de Zotti, R. J. Tuffs, Pasquale Temi, I. Valtchanov, Ivan K. Baldry, Douglas Scott, Rob Ivison, L. Kelvin, Denis Hill, D. J. B. Smith, Michał J. Michałowski, Cristina Popescu, David Bonfield, Steve Serjeant, R. G. Sharp, Loretta Dunne, John A. Peacock, Robbie Richard Auld, James Dunlop, Enzo Pascale, Jochen Liske, S. Buttiglione, Ewan Cameron, E. Ibar, S. J. Maddox, Steven P. Bamford, Simon P. Driver, E. E. Rigby, Antonio Cava, H. Parkinson, Jacopo Fritz, P. van der Werf, Asantha Cooray, E. van Kampen, D. H. P. Jones, M. Pohlen, Jonathan Loveday, Matthew Prescott, Aaron S. G. Robotham, Peder Norberg, and Andrew M. Hopkins

Subjects
Physics, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Redshift, medicine.anatomical_structure, Space and Planetary Science, Atlas (anatomy), 0103 physical sciences, medicine, Spatial clustering, 010306 general physics, Cluster analysis, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We have measured the clustering properties of low-redshift (z < 0.3) sub-mm galaxies detected at 250 micron in the Herschel-ATLAS Science Demonstration Phase (SDP) field. We selected a sample for which we have high-quality spectroscopic redshifts, obtained from reliably matching the 250-micron sources to a complete (for r < 19.4) sample of galaxies from the GAMA database. Both the angular and spatial clustering strength are measured for all z < 0.3 sources as well as for five redshift slices with thickness delta z=0.05 in the range 0.05 < z < 0.3. Our measured spatial clustering length r_0 is comparable to that of optically-selected, moderately star-forming (blue) galaxies: we find values around 5 Mpc. One of the redshift bins contains an interesting structure, at z = 0.164.

Published
2012

10. Galaxy And Mass Assembly (GAMA): stellar mass estimates

Author

William J. Sutherland, Aaron S. G. Robotham, H. Parkinson, Ivan K. Baldry, Sarah Brough, Jon Loveday, Michael J. I. Brown, D. H. P. Jones, Konrad Kuijken, Scott M. Croom, Andrew M. Hopkins, D. Wijesinghe, Matthew Colless, David T. Hill, Joss Bland-Hawthorn, Kevin A. Pimbblet, R. G. Sharp, Jochen Liske, Cristina Popescu, Ewan Cameron, S. Phillipps, Madusha Gunawardhana, Simon P. Driver, John A. Peacock, R. J. Tuffs, Eelco van Kampen, Robert C. Nichol, Edward N. Taylor, C. J. Conselice, Matthew Prescott, Peder Norberg, Steven P. Bamford, Daniel Thomas, Lee S. Kelvin, and Carlos S. Frenk

Subjects
Physics, Stellar mass, Stellar population, 010308 nuclear & particles physics, Estimator, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Redshift survey, 01 natural sciences, Galaxy, Photometry (optics), Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Data release, Astrophysics::Galaxy Astrophysics
Abstract

This paper describes the first catalogue of photometrically-derived stellar mass estimates for intermediate-redshift (z < 0.65) galaxies in the Galaxy And Mass Assembly (GAMA) spectroscopic redshift survey. These masses, as well as the full set of ancillary stellar population parameters, will be made public as part of GAMA data release 2. Although the GAMA database does include NIR photometry, we show that the quality of our stellar population synthesis fits is significantly poorer when these NIR data are included. Further, for a large fraction of galaxies, the stellar population parameters inferred from the optical-plus-NIR photometry are formally inconsistent with those inferred from the optical data alone. This may indicate problems in our stellar population library, or NIR data issues, or both; these issues will be addressed for future versions of the catalogue. For now, we have chosen to base our stellar mass estimates on optical photometry only. In light of our decision to ignore the available NIR data, we examine how well stellar mass can be constrained based on optical data alone. We use generic properties of stellar population synthesis models to demonstrate that restframe colour alone is in principle a very good estimator of stellar mass-to-light ratio, M*/Li. Further, we use the observed relation between restframe (g-i) and M*/Li for real GAMA galaxies to argue that, modulo uncertainties in the stellar evolution models themselves, (g-i) colour can in practice be used to estimate M*/Li to an accuracy of < ~0.1 dex. This 'empirically calibrated' (g-i)-M*/Li relation offers a simple and transparent means for estimating galaxies' stellar masses based on minimal data, and so provides a solid basis for other surveys to compare their results to z < ~0.4 measurements from GAMA.

Published
2011

11. Herschel★-ATLAS: rapid evolution of dust in galaxies over the last 5 billion years

Author

P. van der Werf, David Bonfield, C. Vlahakis, D. J. B. Smith, G. Rodighiero, Pasquale Temi, Simon Dye, Simon P. Driver, Robbie Richard Auld, G. de Zotti, Steve Serjeant, N. Bourne, S. Buttiglione, Matt J. Jarvis, Maarten Baes, A. Dariush, Loretta Dunne, Jacopo Fritz, M. Pohlen, Asantha Cooray, Maggie A. Thompson, Aaron S. G. Robotham, S. J. Maddox, Antonio Cava, Enzo Pascale, James E. Geach, E. E. Rigby, H. L. Gomez, Rob Ivison, L. Kelvin, Stéphane Charlot, D. L. Clements, Cristina Popescu, R. Hopwood, E. da Cunha, E. Ibar, Anne E. Sansom, K. Coppin, Kate Rowlands, Steve Eales, and R. J. Tuffs

Subjects
Physics, Star formation, media_common.quotation_subject, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Mass ratio, Billion years, Galaxy, Redshift, Universe, Space and Planetary Science, Optical depth (astrophysics), Astrophysics::Solar and Stellar Astrophysics, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, media_common
Abstract

We present the first direct and unbiased measurement of the evolution of the dust mass function of galaxies over the past 5 billion years of cosmic history using data from the Science Demonstration Phase of the Herschel-ATLAS. The sample consists of galaxies selected at 250{\mu}m which have reliable counterparts from SDSS at z < 0.5, and contains 1867 sources. Dust masses are calculated using both a single temperature grey-body model for the spectral energy distribution and also using a model with multiple temperature components. The dust temperature for either model shows no trend with redshift. Splitting the sample into bins of redshift reveals a strong evolution in the dust properties of the most massive galaxies. At z = 0.4 - 0.5, massive galaxies had dust masses about five times larger than in the local Universe. At the same time, the dust-to-stellar mass ratio was about 3-4 times larger, and the optical depth derived from fitting the UV-sub-mm data with an energy balance model was also higher. This increase in the dust content of massive galaxies at high redshift is difficult to explain using standard dust evolution models and requires a rapid gas consumption timescale together with either a more top-heavy IMF, efficient mantle growth, less dust destruction or combinations of all three. This evolution in dust mass is likely to be associated with a change in overall ISM mass, and points to an enhanced supply of fuel for star formation at earlier cosmic epochs.

Published
2011

12. Galaxy and Mass Assembly (GAMA): galaxies at the faint end of the Hα luminosity function

Author

Denis Hill, R. J. Tuffs, R. G. Sharp, Scott M. Croom, Cristina Popescu, M. L. P. Gunawardhana, E. N. Taylor, William J. Sutherland, Carlos S. Frenk, Robert C. Nichol, Aaron S. G. Robotham, Jochen Liske, John A. Peacock, K. Kuijken, Simon P. Driver, Steven P. Bamford, H. Parkinson, Caroline Foster, Ewan Cameron, Jonathan Loveday, J. Bland-Hawthorn, Daniel Thomas, K. Pimbblet, Andrew M. Hopkins, Matthew Prescott, Ivan K. Baldry, Peder Norberg, Michael J. I. Brown, E. van Kampen, L. Kelvin, David Heath Jones, D. Wijesinghe, and Sarah Brough

Subjects
Physics, Stars, Space and Planetary Science, Star formation, Low density, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics, Galaxy, Luminosity function (astronomy)
Abstract

We present an analysis of the properties of the lowest Halpha-luminosity galaxies (L_Halpha 10^10 Msun. The low SFR systems are found to exist predominantly in the lowest density environments (median density ~0.02 galaxy Mpc^-2 with none in environments more dense than ~1.5 galaxy Mpc^-2). Their current specific star formation rates (SSFR; -8.5 < log(SSFR[yr^-1])

Published
2011

13. The XXL Survey

Author

Paul Giles, Cathy Horellou, Stefano Ettori, Elias Koulouridis, C. Lidman, V. Smolvcic, Mark Birkinshaw, C. Adami, M. Bolzonella, S. Paltani, T. Sadibekova, Matt S. Owers, R. J. Tuffs, Florian Pacaud, L. Chiappetti, B. Garilli, L. Guennou, S. Maurogordato, Jochen Liske, Andrii Elyiv, Trevor J. Ponman, Meiert W. Grootes, A. Iovino, M. E. Ramos Ceja, Mauro Sereno, Michael J. I. Brown, Sean L. McGee, J. L. Willis, Bruno Altieri, I. Valtchanov, Andrew M. Hopkins, Ivan K. Baldry, Angela Bongiorno, S. Fotoupoulou, Aaron S. G. Robotham, Bianca M. Poggianti, V. Guglielmo, Cristian Vignali, Simon P. Driver, August E. Evrard, Fabio Gastaldello, Benedetta Vulcani, M. Plionis, Marco Scodeggio, Marguerite Pierre, University of St Andrews. School of Physics and Astronomy, Guglielmo, V., Poggianti, B.M., Vulcani, B., Adami, C., Gastaldello, F., Ettori, S., Fotoupoulou, S., Koulouridis, E., Ramos Ceja, M.E., Giles, P., McGee, S., Altieri, B., Baldry, I., Birkinshaw, M., Bolzonella, M., Bongiorno, A., Brown, M., Chiappetti, L., Driver, S., Elyiv, A., Evrard, A., Garilli, B., Grootes, M., Guennou, L., Hopkins, A., Horellou, C., Iovino, A., Lidman, C., Liske, J., Maurogordato, S., Owers, M., Pacaud, F., Paltani, S., Pierre, M., Plionis, M., Ponman, T., Robotham, A., Sadibekova, T., Scodeggio, M., Sereno, M., Smolčić, V., Tuffs, R., Valtchanov, I., Vignali, C., Willis, J., Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
luminosity function, mass function [Galaxies], Stellar mass, astro-ph.GA, FOS: Physical sciences, Astrophysics, clusters: general [Galaxies], 01 natural sciences, Virial theorem, galaxies: groups: general, 0103 physical sciences, QB Astronomy, Infrarot-Astrophysik - Abteilung Hinton, 010303 astronomy & astrophysics, QC, luminosity function [galaxies], QB, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 85A04, 010308 nuclear & particles physics, X-ray, DAS, Astronomy and Astrophysics, Virial mass, evolution [Galaxies], Astrophysics - Astrophysics of Galaxies, NATURAL SCIENCES. Physics, Redshift, Galaxy, PRIRODNE ZNANOSTI. Fizika, galaxies: luminosity function, groups: general [Galaxies], QC Physics, [SDU]Sciences of the Universe [physics], galaxies: clusters: general, mass function, Space and Planetary Science, Homogeneous, Astrophysics of Galaxies (astro-ph.GA), X-rays: galaxies: clusters, galaxies: luminosity function, mass function, galaxies: clusters [X-rays], Halo, galaxies: evolution
Abstract

The fraction of galaxies bound in groups in the nearby Universe is high (50% at z~0). Systematic studies of galaxy properties in groups are important in order to improve our understanding of the evolution of galaxies and of the physical phenomena occurring within this environment. We have built a complete spectrophotometric sample of galaxies within X-ray detected, optically spectroscopically confirmed groups and clusters (G&C), covering a wide range of halo masses at z, 20 pages, 18 figures, 6 tables, accepted for publication in A&A

Published
2018

14. Far-infrared and submillimetre observations of the Crab nebula

Author

David A. Green, Cristina Popescu, and R. J. Tuffs

Subjects
Physics, Spectral index, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Synchrotron, Spectral line, law.invention, Wavelength, Supernova, Crab Nebula, Far infrared, Space and Planetary Science, law, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

We present FIR and sub-mm images of the Crab nebula, taken with ISOPHOT on board ISO and with the SCUBA on the JCMT. The ISOPHOT observations were made at 60, 100, 170 micron, with FWHM of equivalent area Gaussian beams of 44, 47 and 93 arcsec, respectively. The 850 micron SCUBA image has a Gaussian FWHM of 17 arcsec. The 60 and 100 micron images show clear excess of emission above that expected from an extrapolation of the synchrotron spectrum of the Crab nebula from lower frequencies. The ISOPHOT images reveal that about half this excess is attributable to two peaks, separated by approximately 80 arcsec. We also present spectra taken using the LWS on board ISO, which show that the FIR excess is not due to line emission. The lower resolution 170 micron image does not show any excess emission. These findings are consistent with a picture in which the FIR excess is due to emission from a small amount of warm dust which radiates predominantly at 60 and 100 micron micron but not at 170 micron, and which is superimposed on a synchrotron spectrum which gradually steepens towards shorter wavelengths throughout the FIR and MIR spectral range. The dust geometry is consistent with a torus of diameter approximately 0.8 pc created by the supernova progenitor, superimposed upon a broadly distributed component which may be supernova condensates in the filaments. The dust-to-gas ratio in the filaments is comparable to the interstellar value. To study spectral index variations in the radio synchrotron emission we compared the 850-micron image with a 20-cm VLA image. These images are very similar, implying that there is little variation in spectral index across the face of the remnant between these wavelengths.

Published
2004

16. Infrared emission towards SN 1987A, 11 years after outburst: Properties of the circumstellar dust

Author

Jg. Fischera, R. J. Tuffs, and H. J. Voelk

Subjects
Physics, Infrared, Astrophysics::High Energy Astrophysical Phenomena, Evaporation, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Silicate, chemistry.chemical_compound, Supernova, Stars, chemistry, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Circumstellar dust, Spectral energy distribution, Red supergiant, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Detailed models are presented for the late epoch mid infrared (MIR) emission from collisionally heated grains in the shocked circumstellar gas around SN 1987A. Thermal dust emission from a region of moderate density interior to the thick inner ring seen with the Hubble Space Telescope (HST) is found to be a natural explanation for the MIR spectral energy distribution measured by ISOCAM. The MIR-spectrum can be reproduced by a mixture of silicate-iron or silicate-graphite grains or by a composition of pure graphite grains. A composition of pure iron grains on the other hand can be excluded and a pure silicate composition does not seem to be very likely. The dust-to-gas ratio in the interaction zone is ~0.01%, an order of magnitude lower than estimates for dust abundances in the winds of red supergiant (RSG) stars in the LMC. This low dust abundance can be accounted for by a combination of evaporation through the UV-flash from the supernova outburst and subsequent sputtering in the shocked gas. For this explanation to hold, dust in the pre-supernova circumstellar medium (CSM) would have to have been predominantly composed of grains other than graphite, with a maximum size smaller than ~0.1 microns.

Published
2002

17. Galaxy and Mass Assembly (GAMA): Exploring the WISE Web in G12

Author

Thomas H. Jarrett, Mehmet Alpaslan, John A. Peacock, Sarah Brough, Michael J. I. Brown, Simon P. Driver, Scott M. Croom, Joss Bland-Hawthorn, Cristina Popescu, Maciej Bilicki, Andrew M. Hopkins, R. J. Tuffs, Lijun Wang, Elaine M. Sadler, Peder Norberg, Michelle E. Cluver, Jonathan Loveday, Christina Magoulas, Benne W. Holwerda, Edward N. Taylor, and University of St Andrews. School of Physics and Astronomy

Subjects
Stellar mass, Large-scale structure of universe, Scale (descriptive set theory), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Apparent magnitude, statistics [Galaxies], galaxies [Infrared], 0103 physical sciences, QB Astronomy, Cluster analysis, 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, Luminosity function (astronomy), Luminous infrared galaxy, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, 3rd-DAS, evolution [Galaxies], Galaxy, Redshift, QC Physics, Space and Planetary Science
Abstract

We present an analysis of the mid-infrared WISE sources seen within the equatorial GAMA G12 field, located in the North Galactic Cap. Our motivation is to study and characterize the behavior of WISE source populations in anticipation of the deep multi-wavelength surveys that will define the next decade, with the principal science goal of mapping the 3D large scale structures and determining the global physical attributes of the host galaxies. In combination with cosmological redshifts, we identify galaxies from their WISE W1 (3.4μm) resolved emission, and by performing a star-galaxy separation using apparent magnitude, colors and statistical modeling of star-counts. The resultant galaxy catalog has ≃590,000 sources in 60 deg², reaching a W1 5-σ depth of 31 μJy. At the faint end, where redshifts are not available, we employ a luminosity function analysis to show that approximately 27% of all WISE extragalactic sources to a limit of 17.5 mag (31 uJy) are at high redshift, z > 1. The spatial distribution is investigated using two-point correlation functions and a 3D source density characterization at 5 Mpc and 20 Mpc scales. For angular distributions, we find brighter and more massive sources are strongly clustered relative to fainter and lower mass source; likewise, based on WISE colors, spheroidal galaxies have the strongest clustering, while late-type disk galaxies have the lowest clustering amplitudes. Along the radial direction, the strongest clustering is in the largest redshift shell, while the weakest is in the nearest redshift shell, consistent with the stellar mass and morphological type dependency results. In three dimensions, we find a number of distinct groupings, often bridged by filaments and super-structures. Using special visualization tools, we map these structures, exploring how clustering may play a role with stellar mass and galaxy type.

Published
2017

18. Dust Emission from Stephan’s Quintet

Author

G. Natale, R. J. Tuffs, J. Fischera, N. Lu, C. C. Popescu, C. K. Xu, P. Appleton, F. Boulanger, M. Dopita, P. Duc, Y. Gao, P. Ogle, G. Pineau des Forets, W. Reach, J. Sulentic, M. Yun, and Victor P. Debattista

Subjects
Physics, Spiral galaxy, Infrared, Star formation, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Wavelength, Intergalactic medium, Astrophysics::Earth and Planetary Astrophysics, Halo, Astrophysics::Galaxy Astrophysics, Dust emission
Abstract

We present new infrared images of the prototype of galaxy compact groups, Stephan’s Quintet (SQ), taken with Spitzer/MIPS at 24, 70 and 160 μm, and compare these with existing images at X‐ray, UV/optical, radio wavelengths as well as with archival Spitzer/IRAC imaging at 8 μm. The new images reveal an extended (on scales of up to ca. 70 kpc) component of FIR emission which is roughly correlated with diffuse soft X‐ray emission arising from the so‐called SHOCK and HALO regions. A further interesting aspect of this study is the displacement of the main star formation sites from the central galaxy disks to the peripheries of the galaxies or to the intergalactic medium (IGM).

Published
2010

19. Bright FIR emission from the circumstellar torus in the Crab nebula

Author

David A. Green, Cristina Popescu, and R. J. Tuffs

Subjects
Physics, Full width at half maximum, Crab Nebula, Far infrared, law, Resolution (electron density), Extrapolation, Astronomy, Angular resolution, Astrophysics, Synchrotron, Cosmic dust, law.invention
Abstract

ISOPHOT far‐infrared and SCUBA sub‐mm images of the Crab nebula are presented. The ISOPHOT observations were made in the bands centred at 60, 100, 170 μm, with FWHM of equivalent area Gaussian beams of 44, 47 and 93 arcsec, respectively. The 850 μm SCUBA image was processed using a Maximum Entropy Method algorithm and has a Gaussian FWHM of 17 arcsec. The 60 and 100 μm images show clear excess of emission, above that expected from an extrapolation of the synchrotron spectrum of the Crab nebula from lower frequencies, as previously seen from IRAS observations. The superior angular resolution of the ISOPHOT images reveal that about half this excess is attributable to two peaks, separated by ≈ 80 arcsec. The lower resolution 170 μm image does not show any excess emission, but is possibly fainter, particularly in the NW, than expected from an extrapolation of the lower‐frequency synchrotron emission. These findings are consistent with a picture in which the FIR excess is due to emission from a small amount of...

Published
2005

20. The spiral galaxy M33 mapped in the FIR by ISOPHOT: A spatially resolved study of the warm and cold dust

Author

M. Haas, Heinrich J. Voelk, Manfred Stickel, Hans Hippelein, Ulrich Klaas, R. J. Tuffs, and Dietrich Lemke

Subjects
Physics, Spiral galaxy, Star formation, Extinction (astronomy), Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, Galaxy, Stars, Space and Planetary Science, Spectral energy distribution, Surface brightness, Astrophysics::Galaxy Astrophysics
Abstract

The Sc galaxy M33 has been mapped with ISOPHOT in the far-infrared, at 60, 100, and 170mue. The spatial resolution of these FIR maps allows the separation of spiral arms and interarm regions and the isolation of a large number of star-forming regions. The spectral energy distribution in the FIR indicates a superposition of two components, a warm one originating from dust at ~45K, and a cold one, at ~16K. The warm component is concentrated towards the spiral arms and the star-forming regions, and is likely heated by the UV radiation from OB stars. The cold component is more smoothly distributed over the disk, and heated by the diffuse interstellar radiation. For the about 60 star-forming regions detected the H-alpha/FIR flux ratio increases significantly with the distance from the galaxy center, probably due to decreasing extinction. An anti-correlation of F_Ha/F_60 with F_170 suggests the intrinsic extinction to be related to the cold dust surface brightness according to A_V/S_170~0.03mag/MJy*sr. For the total galaxy the star formation rate (SFR) derived from the FIR is in agreement with that derived from the de-extincted H-alpha emission. For individual star-forming regions, a consistency between SFRs derived from the optical and from the FIR requires only a fraction of the UV radiation to be absorbed locally. The individual star-forming regions also show a local radio-FIR correlation. This local correlation is, however, due to quite different components than to those that lead to the well-known global radio-FIR correlation for entire galaxies., Comment: 10 pages, 9 figures; the full resolution images of Fig.1 can be obtained by anonymous ftp from ftp.mpia.de /pub/iso-arch

Published
2003
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21. Observations of Supernova Remnants with ISO

Author

R. J. Tuffs

Subjects
Physics, Cygnus Loop, Supernova, Astrophysics::High Energy Astrophysical Phenomena, Molecular cloud, Radiative transfer, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Near-Earth supernova, Ejecta, Supernova remnant, Astrophysics::Galaxy Astrophysics, Galaxy
Abstract

Pointed observations with ISO have been made, or are planned, towards 58 supernova remnants (SNRs) in the galaxy and Magellanic clouds. The main emphasis is on detailed studies of gas, dust and synchrotron emission from selected regions within 24 well studied galactic remants. First results are available for Cas A (Lagage et al. 1996, 1997; Tuffs et al. 1997; Unger et al. 1997), the Cygnus Loop (deCourchelle et al 1997; Fischera et al. 1997), RCW103 (Oliva et al. 1997; Wright et al. 1997), and W44 and 3C391 (Reach and Rho 1996). These are providing insights into issues such as the yield and composition of condensates in supernova ejecta, the processing of grains by adiabatic and radiative shocks, and the measurement of cold gas, inaccessible to optical observations, both from cool regions in radiative shocks and from unshocked ejecta. In this progress report these points are illustrated with reference to Cas A, the prototype of an ejecta-dominated remnant of a massive core-collapse supernova, and the Cygnus Loop and RCW103 as prime examples of radiative shocks delineating the interaction of fast blast waves with diffuse atomic and dense molecular clouds, respectively.

Published
1998

22. Galaxy And Mass Assembly (GAMA): the mass-metallicity relationship

Author

David Thomas, Scott M. Croom, M. L. P. Gunawardhana, Robert C. Nichol, Matthew Prescott, Carlos S. Frenk, Andrew M. Hopkins, Peder Norberg, Matthew Colless, R. J. Tuffs, Kevin A. Pimbblet, I. K. Baldryi, Konrad Kuijken, Ewan Cameron, Maritza A. Lara-López, Rob Sharp, Steven P. Bamford, Edward N. Taylor, Jochen Liske, D. Wijesinghe, Matt S. Owers, Christopher J. Conselice, William J. Sutherland, Aaron S. G. Robotham, Denis Hill, Simon P. Driver, Jonathan Loveday, John A. Peacock, Sarah Brough, Caroline Foster, H. Parkinson, Mehmet Alpaslan, A. Bauer, E. van Kampen, Angel R. Lopez-Sanchez, L. Kelvin, D. H. P. Jones, Joss Bland-Hawthorn, O. Steele, and Cristina Popescu

Subjects
Physics, Absolute magnitude, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Metallicity, media_common.quotation_subject, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Redshift, Galaxy, Luminosity, Space and Planetary Science, Sky, Range (statistics), Astrophysics - Cosmology and Nongalactic Astrophysics, media_common
Abstract

Context: The mass-metallicity relationship (MMR) of star-forming galaxies is well-established, however there is still some disagreement with respect to its exact shape and its possible dependence on other observables. Aims: We measure the MMR in the Galaxy And Mass Assembly (GAMA) survey. We compare our measured MMR to that measured in the Sloan Digital Sky Survey (SDSS) and study the dependence of the MMR on various selection criteria to identify potential causes for disparities seen in the literature. Methods: We use strong emission line ratio diagnostics to derive oxygen abundances. We then apply a range of selection criteria for the minimum signal-to-noise in various emission lines, as well as the apparent and absolute magnitude to study variations in the inferred MMR. Results: The shape and position of the MMR can differ significantly depending on the metallicity calibration and selection used. After selecting a robust metallicity calibration amongst those tested, we find that the mass-metallicity relation for redshifts 0.061< z, Comment: 10 pages, 6 figures, accepted for publication in A&A

Published
2012

23. 7.1. NIR and mm mosaics of the central 100 pc

Author

R. J. Tuffs, Tom Herbst, S. Philipp, Wolfgang J. Duschl, R. Zylka, and P. G. Mezger

Subjects
Physics, Stars, Optics, Bulge, Young population, Star formation, business.industry, Astrophysics, business, Galaxy
Abstract

The conditions within the nuclear bulge (NB, R ~ 300 pc) of our Galaxy are extreme: less than 0.1% of the volume of the galactic disc contains more than 10% of the total ISM and stars. There are indications that star formation in the NB is not a continuous process, but rather undergoes cyclic variations. Details of the current and past star formation processes and the stellar content of the central parsecs - especially the ratio of old to young population - are not very well known (Mezger et al., 1996).

Published
1998

24. Erratum: 'Physical Conditions and Star Formation Activity in the Intragroup Medium of Stephan's Quintet' (ApJ, 595, 665 [2003])

Author

N. Lu, Cong Xu, James J. Condon, Michael A. Dopita, and R. J. Tuffs

Subjects
Physics, Space and Planetary Science, Position (vector), Star formation, Astronomy, Astronomy and Astrophysics, Astrophysics, Table (information), Slit
Abstract

In x 4.1, when describing the optical long-slit observations, there was a mistake in the reported position of slit N, due to a typo. The central position of slit N should be 223559. 6, +33 5800000 (J2000.0), instead of 223559. 8, +33 5800000 (J2000.0). This also affects the positions of the spectroscopic sources along slit N given in Table 4 (together with sources along slit M). Here we give a new Table 4 with the mistakes corrected.

Published
2005

25. Neutral hydrogen towards 3C 10, the remnant of Tycho's supernova

Author

Elizabeth Swinbank, S. F. Gull, J. S. Albinson, and R. J. Tuffs

Subjects
Physics, Hydrogen, Astronomy, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, Near-Earth supernova, Spectral line, Radial velocity, Supernova, chemistry, Space and Planetary Science, Brightness temperature, Supernova remnant, Open cluster
Published
1986

26. The Expansion of Cassiopeia A

Author

R. J. Tuffs

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

This paper describes a detailed comparison of radio maps of Cas A obtained with the Cambridge 5 km Radio Telescope in 1974 and 1978. Accurate proper motions and brightness changes are presented for 342 distinct radio peaks, ranging in angular size from 1 arc minute for fragments of the intense ring to less than the resolution limit of 2.0 × 2.3 arc seconds for the compact radio knots.

Published
1983

27. Secular changes within Cassiopeia A at 5 GHz-I

Author

R. J. Tuffs

Subjects
Physics, Cassiopeia A, Brightness, Proper motion, Space and Planetary Science, Phase error, Astronomy, Astronomy and Astrophysics, Astrometry, Astrophysics, Supernova remnant, Secular variation, Radio astronomy
Abstract

On presente une comparaison detaillee des cartes radio a 5 GHz de CasA, obtenues avec le radiotelescope de 5 km de Cambridge en 1974 et 1978. On donne les mouvements propres precis et les changements d'eclats de 342 pics radio distincts

Published
1986

28. Continuum observations of Sgr A at mm/submm wavelengths

Author

Peter G. Mezger, Ernst Kreysa, J. E. Wink, Rolf Chini, Chris Salter, R. Zylka, and R. J. Tuffs

Subjects
Physics, Wavelength, Infrared astronomy, Stellar mass, Molecular cloud, Galactic Center, Astronomy, Emission spectrum, Astronomical spectroscopy, Cosmic dust
Abstract

We have mapped the source complex Sgr A (containing Sgr A West and East) at λ2.8mm, 1.3mm and 350/μm using the IRAM 30m MRT (Pico Veleta, Spain) and the 3m IRTF (Mauna Kea, Hawaii) telescopes. Detailed results have been published or will be published elsewhere (Mezger et al., 1986, Paper I; Zylka and Mezger, 1988, Paper II; Mezger et al., 1988, Paper III).

Published
1989

29. The Expansion of Cassiopeia A

Author

R. J. Tuffs

Subjects
Physics, Radial velocity, Cassiopeia A, Radio telescope, Brightness, Proper motion, Angular diameter, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astronomical spectroscopy, Radio astronomy
Abstract

This paper describes a detailed comparison of radio maps of Cas A obtained with the Cambridge 5 km Radio Telescope in 1974 and 1978. Accurate proper motions and brightness changes are presented for 342 distinct radio peaks, ranging in angular size from 1 arc minute for fragments of the intense ring to less than the resolution limit of 2.0 × 2.3 arc seconds for the compact radio knots.

Published
1983

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