397 research outputs found
Gamma-Ray Burst observation at Very High Energy with H.E.S.S.
No full textFermi-LAT observations have proven that GeV gamma-ray emission is a relatively common feature for many Gamma Ray Bursts (GRB). However the low effective area of space detectors implies low statistics for high-energy photons which prevent any physical interpretation at such energy range. The current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) arrays of >10^4 m^2 effective area above a few tens of GeV is able to detect higher-energy photons.
The High Energy Stereoscopic System (H.E.S.S.) is one of the current generation of IACTs. The large light collection area of the largest telescope and its fast slewing make it perfectly suitable to observe γ rays below 100 GeV with an unprecedented sensitivity. Several tens of GRBs have been observed since 2007. This contribution is about the results of this large sample of observation above a few tens of GeV
Gravitational wave alert follow-up strategy in the H.E.S.S. multi-messenger framework
No full textInternational audienceThe H.E.S.S. high-energy gamma-ray observatory is member of the Virgo/LIGO electromagnetic follow-up effort since early 2014. Its capability for transient follow-up studies benefits from its large field of view, rapid response time and high sensitivity. Drawing from the experience gained from other science cases like gamma-ray bursts and high-energy neutrino follow-ups we demonstrate the high perspectives for new types of analyses like the search for gravitational wave counterparts and the study of multi-messenger signals from binary neutron star mergers. This contribution aims to present the potential pointing strategy that the H.E.S.S. observatory would carry out following an alert from gravitational wave observatories. We will discuss several key points like the use of information from a galaxy catalogue, the time-dependent visibility of sky regions and the automatic handling of gravitational wave uncertainty maps, that will enable an optimized choice of the pointing directions. Finally, based on simulated binary neutron star mergers, the performance of the outlined gravitational wave-alert observations will be presented
Gravitational wave alert follow-up strategy in the H.E.S.S. multi-messenger framework
No full textInternational audienceThe H.E.S.S. high-energy gamma-ray observatory is member of the Virgo/LIGO electromagnetic follow-up effort since early 2014. Its capability for transient follow-up studies benefits from its large field of view, rapid response time and high sensitivity. Drawing from the experience gained from other science cases like gamma-ray bursts and high-energy neutrino follow-ups we demonstrate the high perspectives for new types of analyses like the search for gravitational wave counterparts and the study of multi-messenger signals from binary neutron star mergers. This contribution aims to present the potential pointing strategy that the H.E.S.S. observatory would carry out following an alert from gravitational wave observatories. We will discuss several key points like the use of information from a galaxy catalogue, the time-dependent visibility of sky regions and the automatic handling of gravitational wave uncertainty maps, that will enable an optimized choice of the pointing directions. Finally, based on simulated binary neutron star mergers, the performance of the outlined gravitational wave-alert observations will be presented
Target of opportunity observations of blazars with H.E.S.S.
No full textThe very-high-energy (VHE, E>100 GeV) extragalactic sky is dominated by blazars, a class of
active galactic nuclei which show rapid variability at all wavelengths. Target of Opportunity (ToO)
observations triggered by flaring activity detected at longer wavelengths are, thus, an important
part of the blazar observing strategy of H.E.S.S., an array of five imaging atmospheric Cherenkov
telescopes sensitive to VHE photons.
In this contribution we detail the H.E.S.S. extragalactic ToO program, describing the specific
procedures currently in place to follow up on multi-wavelength alerts. The program is illustrated
by discussing a few recent noteworthy targets observed with the H.E.S.S. phase II array over the
last two years of blazar ToO observation
The Advanced Virgo Photon Calibrators
No full textInternational audienceAs the sensitivities of LIGO, Virgo and KAGRA detectors improve, calibration of the interferometers (ITFs) output is becoming more and more important and may impact scientific results. For the observing run O3, Virgo used for the first time photon calibrators (PCals) to calibrate the ITF, using radiation pressure of a modulated auxiliary laser beam impinging on the Advanced Virgo end mirrors. Those optical devices, also used in LIGO, are now the calibration reference for the global gravitational wave detectors network. The intercalibration of LIGO and Virgo PCals, based on the same absolute reference called the gold standard, has allowed to remove a systematic bias of 3.92% that would have been present in Virgo calibration using the PCal. The uncertainty budget on the PCal-induced displacement of the end mirrors [North end (NE) and West end (WE)] of Advanced Virgo has been estimated to be 1.36% for O3a and 1.40% on NE PCal (resp. 1.74% on WE PCal) for O3b. This uncertainty is the limiting one for the global calibration of Advanced Virgo. It is expected to be reduced below ∼1% for the next observing runs
GW231123:a binary black hole merger with total mass 190–265 <i>M</i><sub>⊙</sub>
No full textOn 2023 November 23, the two LIGO observatories both detected GW231123, a gravitational-wave signal consistent with the merger of two black holes with masses 137+23-18 M⊙ and 101+22-50 M⊙ (90% credible intervals), at a luminosity distance of 0.7–4.1 Gpc, a redshift of 0.40+0.27-0.25, and with a network signal-to-noise ratio of ∼20.7. Both black holes exhibit high spins— 0.90+0.10-0.19 and 0.80+0.20-0.52, respectively. A massive black hole remnant is supported by an independent ringdown analysis. Some properties of GW231123 are subject to large systematic uncertainties, as indicated by differences in the inferred parameters between signal models. The primary black hole lies within or above the theorized mass gap where black holes between 60–130 M⊙ should be rare, due to pair-instability mechanisms, while the secondary spans the gap. The observation of GW231123 therefore suggests the formation of black holes from channels beyond standard stellar collapse and that intermediate-mass black holes of mass ∼200 M⊙ form through gravitational-wave-driven mergers
Igualdad de oportunidades respetando las diferencias : encuesta escolar
No full textRealizar una encuesta escolar sobre actitudes de solidaridad y xenofobia ante otros pueblos y culturas, comparando sus resultados con la encuesta escolar realizada en 1986 sobre esta misma temática. Conocer las actitudes positivas y negativas de la mayoría escolar, con quienes han de convivir los niños de las minorías étnicas que acuden a los centros escolares en España. 5168 encuestados. La muestra es estratificada con selección en base a cuotas de nivel escolar (EGB, BUP, COU, FP), sexo, edad, tipo de colegio (público, privado religioso, privado seglar), tamaño de la población, comunidades autónomas, y provincias. La metodología es una combinación de técnicas sociológicas y antropológicas cualitativas. Se utiliza como instrumento un cuestionario de 74 preguntas cerradas, posibilitando a los escolares hacer una redacción libre sobre la temática expuesta. La encuesta es de ámbito nacional, realizada en las 17 comunidades autónomas, en 41 provincias, en 70 puntos geográficos, en 110 colegios, y en 120 aulas escolares. La forma de realización es de autocumplimiento. El nivel de confianza es del 95,5 con un margen de error de mas-menos 3 para datos globales. El tratamiento estadístico se ha realizado en el centro de cálculo y aplicaciones informáticas de Odec-Unitec de Madrid. Porcentajes, tablas. 1. Existe un preocupante auge de las actitudes xenófobas y racistas en un sector del alumnado, habiendo crecido desde 1986 a 1993, como lo ponen de manifiesto estos datos: un 11,4 por ciento de escolares echaría en 1986 a los gitanos de España, hoy (1993) es un 30,8 por ciento, y así sucesivamente con otros grupos (moros-árabes, en 1986, un 11,1 por ciento y en 1993, un 26,1 por ciento; negros de África, en 1986, un 4,2 por ciento y en 1993, un 14,1 por ciento; portugueses, en 1986, un 6,6 por ciento y en 1993, un 11,4 por ciento; latinoamericanos, en 1986, un 4,2 por ciento y en 1993, un 6,4 por ciento; franceses-ingleses, en 1986, un 6,0 por ciento y en 1993, un 3,8 por ciento). 2. Se han hecho militantes activos en defensa de los extranjeros algunos jóvenes solidarios y tolerantes. 3. Existe un problema grave de falta de confianza en las instituciones públicas y en los partidos políticos. 4. Los jóvenes sueñan en causas nobles, pacíficas, solidarias, admirando a los personajes-símbolos que los representan 5. La familia, y en parte la Iglesia, son las dos instituciones básicas, junto con la escuela, que más cerca se sienten defendiendo la igualdad entre los seres. 6. Tienen porcentajes preocupantes de permisividad ante la borrachera y las relaciones sexuales prematrimoniales. 7. Es una juventud de moral complaciente, de creencias religiosas y bastante satisfecha.Biblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; Fax +34917748026; [email protected]
Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
No full textFull list of authors: Abdalla, H.; Abe, H.; Acero, F.; Acharyya, A.; Adam, R.; Agudo, I; Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio, R.; Batista, R. Alves; Amati, L.; Amato, E.; Ambrosi, G.; Anguner, E. O.; Araudo, A.; Armstrong, T.; Arqueros, F.; Arrabito, L.; Asano, K.; Ascasibar, Y.; Ashley, M.; Backes, M.; Balazs, C.; Balbo, M.; Balmaverde, B.; Baquero Larriva, A.; Martins, V. Barbosa; Barkov, M.; Baroncelli, L.; de Almeida, U. Barres; Barrio, J. A.; Batista, P-, I; Becerra Gonzalez, J.; Becherini, Y.; Beck, G.; Tjus, J. Becker; Belmont, R.; Benbow, W.; Bernardini, E.; Berti, A.; Berton, M.; Bertucci, B.; Beshley, V; Bi, B.; Biasuzzi, B.; Biland, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Bocchino, F.; Boisson, C.; Bolmont, J.; Bonanno, G.; Arbeletche, L. Bonneau; Bonnoli, G.; Bordas, P.; Bottacini, E.; Bottcher, M.; Bozhilov, V; Bregeon, J.; Brill, A.; Brown, A. M.; Bruno, P.; Bruno, A.; Bulgarelli, A.; Burton, M.; Buscemi, M.; Caccianiga, A.; Cameron, R.; Capasso, M.; Caprai, M.; Caproni, A.; Capuzzo-Dolcetta, R.; Caraveo, P.; Carosi, R.; Carosi, A.; Casanova, S.; Cascone, E.; Cauz, D.; Cerny, K.; Cerruti, M.; Chadwick, P.; Chaty, S.; Chen, A.; Chernyakova, M.; Chiaro, G.; Chiavassa, A.; Chytka, L.; Conforti, V; Conte, F.; Contreras, J. L.; Coronado-Blazquez, J.; Cortina, J.; Costa, A.; Costantini, H.; Covino, S.; Cristofari, P.; Cuevas, O.; D'Ammando, F.; Daniel, M. K.; Davies, J.; Dazzi, F.; De Angelis, A.; de Lavergne, M. de Bony; De Caprio, V; dos Anjos, R. de Cassia; Dal Pino, E. M. de Gouveia; De Lotto, B.; De Martino, D.; de Naurois, M.; Wilhelmi, E. de Ona; De Palma, F.; de Souza, V; Delgado, C.; Della Ceca, R.; della Volpe, D.; Depaoli, D.; Di Girolamo, T.; Di Pierro, F.; Diaz, C.; Diaz-Bahamondes, C.; Diebold, S.; Djannati-Atai, A.; Dmytriiev, A.; Dominguez, A.; Donini, A.; Dorner, D.; Doro, M.; Dournaux, J.; Dwarkadas, V. V.; Ebr, J.; Eckner, C.; Einecke, S.; Ekoume, T. R. N.; Elsaesser, D.; Emery, G.; Evoli, C.; Fairbairn, M.; Falceta-Goncalves, D.; Fegan, S.; Feng, Q.; Ferrand, G.; Fiandrini, E.; Fiasson, A.; Fioretti, V; Foffano, L.; Fonseca, M., V; Font, L.; Fontaine, G.; Franco, F. J.; Freixas Coromina, L.; Fukami, S.; Fukazawa, Y.; Fukui, Y.; Gaggero, D.; Galanti, G.; Gammaldi, V; Garcia, E.; Garczarczyk, M.; Gascon, D.; Gaug, M.; Gent, A.; Ghalumyan, A.; Ghirlanda, G.; Gianotti, F.; Giarrusso, M.; Giavitto, G.; Giglietto, N.; Giordano, F.; Glicenstein, J.; Goldoni, P.; Gonzalez, J. M.; Gourgouliatos, K.; Grabarczyk, T.; Grandi, P.; Granot, J.; Grasso, D.; Green, J.; Grube, J.; Gueta, O.; Gunji, S.; Halim, A.; Harvey, M.; Collado, T. Hassan; Hayashi, K.; Heller, M.; Cadena, S. Hernandez; Hervet, O.; Hinton, J.; Hiroshima, N.; Hnatyk, B.; Hnatyk, R.; Hoffmann, D.; Hofmann, W.; Holder, J.; Horan, D.; Horandel, J.; Horvath, P.; Hovatta, T.; Hrabovsky, M.; Hrupec, D.; Hughes, G.; Hutten, M.; Iarlori, M.; Inada, T.; Inoue, S.; Insolia, A.; Ionica, M.; Iori, M.; Jacquemont, M.; Jamrozy, M.; Janecek, P.; Jimenez Martinez, I; Jin, W.; Jung-Richardt, I; Jurysek, J.; Kaaret, P.; Karas, V; Karkar, S.; Kawanaka, N.; Kerszberg, D.; Khelifi, B.; Kissmann, R.; Knodlseder, J.; Kobayashi, Y.; Kohri, K.; Komin, N.; Kong, A.; Kosack, K.; Kubo, H.; La Palombara, N.; Lamanna, G.; Lang, R. G.; Lapington, J.; Laporte, P.; Lefaucheur, J.; Lemoine-Goumard, M.; Lenain, J.; Leone, F.; Leto, G.; Leuschner, F.; Lindfors, E.; Lloyd, S.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez, A.; Lopez, M.; Lopez-Coto, R.; Loporchio, S.; Lucarelli, F.; Luque-Escamilla, P. L.; Lyard, E.; Maggio, C.; Majczyna, A.; Makariev, M.; Mallamaci, M.; Mandat, D.; Maneva, G.; Manganaro, M.; Manico, G.; Marcowith, A.; Marculewicz, M.; Markoff, S.; Marquez, P.; Marti, J.; Martinez, O.; Martinez, M.; Martinez, G.; Martinez-Huerta, H.; Maurin, G.; Mazin, D.; Mbarubucyeye, J. D.; Miranda, D. Medina; Meyer, M.; Micanovic, S.; Miener, T.; Minev, M.; Miranda, J. M.; Mitchell, A.; Mizuno, T.; Mode, B.; Moderski, R.; Mohrmann, L.; Molina, E.; Montaruli, T.; Moralejo, A.; Morales Merino, J.; Morcuende-Parrilla, D.; Morselli, A.; Mukherjee, R.; Mundell, C.; Murach, T.; Muraishi, H.; Nagai, A.; Nakamori, T.; Nemmen, R.; Niemiec, J.; Nieto, D.; Nievas, M.; Nikolajuk, M.; Nishijima, K.; Noda, K.; Nosek, D.; Nozaki, S.; Ohira, Y.; Ohishi, M.; Oka, T.; Ong, R. A.; Orienti, M.; Orito, R.; Orlandini, M.; Orlando, E.; Osborne, J. P.; Ostrowski, M.; Oya, I; Pagliaro, A.; Palatka, M.; Paneque, D.; Pantaleo, F. R.; Paredes, J. M.; Parmiggiani, N.; Patricelli, B.; Pavletic, L.; Pe'er, A.; Pech, M.; Pecimotika, M.; Peresano, M.; Persic, M.; Petruk, O.; Pfrang, K.; Piatteli, P.; Pietropaolo, E.; Pillera, R.; Pilszyk, B.; Pimentel, D.; Pintore, F.; Pita, S.; Pohl, M.; Poireau, V; Polo, M.; Prado, R. R.; Prast, J.; Principe, G.; Produit, N.; Prokoph, H.; Prouza, M.; Przybilski, H.; Pueschel, E.; Puehlhofer, G.; Pumo, M. L.; Punch, M.; Queiroz, F.; Quirrenbach, A.; Rando, R.; Razzaque, S.; Rebert, E.; Recchia, S.; Reichherzer, P.; Reimer, O.; Reimer, A.; Renier, Y.; Reposeur, T.; Rhode, W.; Ribeiro, D.; Ribo, M.; Richtler, T.; Rico, J.; Rieger, F.; Rizi, V; Rodriguez, J.; Fernandez, G. Rodriguez; Ramirez, J. C. Rodriguez; Rodriguez Vazquez, J. J.; Romano, P.; Romeo, G.; Roncadelli, M.; Rosado, J.; de Leon, A. Rosales; Rowell, G.; Rudak, B.; Rujopakarn, W.; Russo, F.; Sadeh, I; Saha, L.; Saito, T.; Greus, F. Salesa; Sanchez, D.; Sanchez-Conde, M.; Sangiorgi, P.; Sano, H.; Santander, M.; Santos, E. M.; Sanuy, A.; Sarkar, S.; Saturni, F. G.; Sawangwit, U.; Scherer, A.; Schleicher, B.; Schovanek, P.; Schussler, F.; Schwanke, U.; Sciacca, E.; Scuderi, S.; Arroyo, M. Seglar; Sergijenko, O.; Servillat, M.; Seweryn, K.; Shalchi, A.; Sharma, P.; Shellard, R. C.; Siejkowski, H.; Sinha, A.; Sliusar, V; Slowikowska, A.; Sokolenko, A.; Sol, H.; Specovius, A.; Spencer, S.; Spiga, D.; Stamerra, A.; Starling, R.; Stolarczyk, T.; Straumann, U.; Striskovic, J.; Suda, Y.; Tagliaferri, G.; Takahashi, H.; Takahashi, M.; Tavecchio, F.; Taylor, L.; Tejedor, L. A.; Temnikov, P.; Terrier, R.; Terzic, T.; Testa, V; Tian, W.; Tibaldo, L.; Tonev, D.; Torres, D. F.; Torresi, E.; Tosti, L.; Tothill, N.; Tovmassian, G.; Travnicek, P.; Truzzi, S.; Tuossenel, F.; Umana, G.; Vacula, M.; Vagelli, V.; Valentino, M.; Vallage, B.; Vallania, P.; van Eldik, C.; Varner, G. S.; Vassiliev, V.; Vazquez Acosta, M.; Vecchi, M.; Veh, J.; Vercellone, S.; Vergani, S.; Verguilov, V.; Vettolani, G. P.; Viana, A.; Vigorito, C. F.; Vitale, V.; Vorobiov, S.; Vovk, I; Vuillaume, T.; Wagner, S. J.; Walter, R.; Watson, J.; White, M.; White, R.; Wiemann, R.; Wierzcholska, A.; Will, M.; Williams, D. A.; Wischnewski, R.; Wolter, A.; Yamazaki, R.; Yanagita, S.; Yang, L.; Yoshikoshi, T.; Zacharias, M.; Zaharijas, G.; Zaric, D.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech, A.; Zechlin, H.; Zhdanov, V., I; Zivec, M.The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of γ cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of γ absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z=2 and to constrain or detect γ halos up to intergalactic-magnetic-field strengths of at least 0.3 pG . Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from γ astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of γ cosmology. © 2021 IOP Publishing Ltd and Sissa Medialab.We gratefully acknowledge financial support from the following agencies and organizations: State Committee of Science of Armenia, Armenia; The Australian Research Council, Astronomy Australia Ltd, The University of Adelaide, Australian National University, Monash University, The University of New South Wales, The University of Sydney, Western Sydney University, Australia; Federal Ministry of Education, Science and Research, and Innsbruck University, Austria; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq),
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Ministry of Science, Technology, Innovations and Communications (MCTIC), Brasil; Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018, Bulgaria; The Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency, Canada; CONICYT-Chile grants CATA AFB 170002, ANID PIA/APOYO AFB 180002, ACT 1406, FONDECYT-Chile grants, 1161463, 1170171, 1190886, 1171421, 1170345, 1201582, Gemini-ANID 32180007, Chile; Croatian Science Foundation, Rudjer Boskovic Institute, University of Osijek, University of Rijeka, University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Zagreb, Faculty of Electrical Engineering and Computing, Croa tia; Ministry of Education, Youth and Sports, MEYS M2015046, LM2018105, LTT17006, EU/MEYS CZ.02.1.01/0.0/0.0/16_013/0001403, CZ.02.1.01/0.0/0.0/18_046/0016007 and CZ.02.1.01/0.0/0.0/16_019/0000754, Czech Republic; Academy of Finland (grant nr.317636 and 320045), Finland; Ministry of Higher Education and Research, CNRS-INSU and CNRS-IN2P3, CEA-Irfu, ANR, Regional
Council Ile de France, Labex ENIGMASS, OCEVU, OSUG2020 and P2IO, France; Max Planck Society, BMBF, DESY, Helmholtz Association, Germany; Department of Atomic Energy, Department of Science and Technology, India; Istituto Nazionale di Astrofisica (INAF), Istituto Nazionale di Fisica Nucleare (INFN), MIUR, Istituto Nazionale di Astrofisica (INAF-OABRERA) Grant Fondazione Cariplo/Regione Lombardia ID 2014-1980/RST_ERC, Italy; ICRR, University of Tokyo, JSPS, MEXT, Japan; Netherlands Research School for Astronomy (NOVA), Netherlands Organization for Scientific Research (NWO), Netherlands; University of Oslo, Norway; Ministry of Science and Higher Education, DIR/WK/2017/12, the National Centre for Research and Development and the National Science Centre, UMO-2016/22/M/ST9/00583, Poland; Slovenian Research Agency, grants P1-0031, P1-0385, I0-0033, J1-9146, J1-1700, N1-0111, and the Young Researcher program, Slovenia; South African Department of Science and Technology and National Research Foundation through the South African Gamma-Ray Astronomy Programme, South Africa; The Spanish groups acknowledge the Spanish Ministry of Science and Innovation and the Spanish Research State Agency (AEI) through grants AYA2016-79724-C4-1-P, AYA2016-80889-P, AYA2016-76012-C3-1-P, BES-2016-076342, FPA2017-82729-C6-1-R, FPA2017-82729-C6-2-R, FPA2017-82729-C6-3-R, FPA2017-82729-C6-4-R, FPA2017-82729-C6-5-R, FPA2017-82729-C6-6-R, PGC2018-095161-B-I00, PGC2018-095512-B-I00, PID2019-107988GB-C22; the “Centro de Excelencia Severo Ochoa” program through grants no. SEV-2016-0597, SEV-2016-0588, SEV-2017-0709, CEX2019-000920-S; the “Unidad de Excelencia María de Maeztu” program through grant no. MDM-2015-0509; the “Ramón y Cajal” programme through grants RYC-2013-14511, RYC-2017-22665; and the MultiDark Consolider Network FPA2017-90566-REDC. They also acknowledge the Atracción de Talento contract no. 2016-T1/TIC-1542 granted by the Comunidad de Madrid; the “Postdoctoral Junior Leader Fellowship” programme from La Caixa Bank ing Foundation, grants no. LCF/BQ/LI18/11630014 and LCF/BQ/PI18/11630012; the “Programa Operativo” FEDER 2014-2020, Consejería de Economía y Conocimiento de la Junta de Andalucía (Ref. 1257737), PAIDI 2020 (Ref. P18-FR-1580) and Universidad de Jaén; “Programa Operativo de Crecimiento Inteligente” FEDER 2014-2020 (Ref. ESFRI-2017-IAC-12),
Ministerio de Ciencia e Innovación, 15% co-financed by Consejería de Economía, Industria, Comercio y Conocimiento del Gobierno de Canarias; the Spanish AEI EQC2018-005094-P FEDER 2014-2020; the European Union’s “Horizon 2020” research and innovation programme under Marie Skłodowska-Curie grant agreement no. 665919; and the ESCAPE project with grant no. GA:824064; Swedish Research Council, Royal Physiographic Society of Lund, Royal Swedish Academy of Sciences, The Swedish National Infrastructure for Computing (SNIC) at Lunarc (Lund), Sweden; State Secretariat for Education, Research and Innovation (SERI)
and Swiss National Science Foundation (SNSF), Switzerland; Durham University, Leverhulme Trust, Liverpool University, University of Leicester, University of Oxford, Royal Soci ety, Science and Technology Facilities Council, UK; U.S. National Science Foundation, U.S. Department of Energy, Argonne National Laboratory, Barnard College, University of California, University of Chicago, Columbia University, Georgia Institute of Technology, Institute for Nuclear and Particle Astrophysics (INPAC-MRPI program), Iowa State University, the
Smithsonian Institution, Washington University McDonnell Center for the Space Sciences, The University of Wisconsin and the Wisconsin Alumni Research Foundation, USA. The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreements No 262053 and No 317446. This project is receiving funding from the European Union’s Horizon 2020 research and innovation programs under agreement No 676134. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement GammaRayCascades No 843800. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à
l’Energie Atomique and the Centre National de la Recherche Scientifique / Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515.Peer reviewe
Chasing Gravitational Waves with the Cherenkov Telescope Array
No full textThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA
Multiwavelength study of OT 081: broadband modelling of a transitional blazar
No full textAbe, H. et al.-- Full list of authors: Abe, H.; Abe, S.; Acciari, V. A.; Agudo, I.; Aniello, T.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Arcaro, C.; Artero, M.; Asano, K.; Baack, D.; Babić, A.; Baquero, A.; Barres de Almeida, U.; Batković, I.; Baxter, J.; Bernardini, E.; Bernardos, M.; Bernete, J.; Berti, A.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Bošnjak, Ž.; Burelli, I.; Busetto, G.; Campoy-Ordaz, A.; Carosi, A.; Carosi, R.; Carretero-Castrillo, M.; Castro-Tirado, A. J.; Chai, Y.; Cifuentes, A.; Cikota, S.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; Del Popolo, A.; Delfino, M.; Delgado, J.; Delgado Mendez, C.; Depaoli, D.; Di Pierro, F.; Di Venere, L.; Dominis Prester, D.; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Emery, G.; Escudero, J.; Fariña, L.; Fattorini, A.; Foffano, L.; Font, L.; Fukami, S.; Fukazawa, Y.; García López, R. J.; Gasparyan, S.; Gaug, M.; Giesbrecht Paiva, J. G.; Giglietto, N.; Giordano, F.; Gliwny, P.; Grau, R.; Green, J. G.; Hadasch, D.; Hahn, A.; Heckmann, L.; Herrera, J.; Hrupec, D.; Hütten, M.; Imazawa, R.; Inada, T.; Iotov, R.; Ishio, K.; Jiménez Martínez, I.; Jormanainen, J.; Kerszberg, D.; Kluge, G. W.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Láinez Lezáun, M.; Lamastra, A.; Leone, F.; Lindfors, E.; Linhoff, L.; Lombardi, S.; Longo, F.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Lorini, A.; Machado de Oliveira Fraga, B.; Majumdar, P.; Makariev, M.; Maneva, G.; Mang, N.; Manganaro, M.; Mangano, S.; Mannheim, K.; Mariotti, M.; Martínez, M.; Mas-Aguilar, A.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, S.; Miceli, D.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Mondal, H. A.; Morcuende, D.; Nanci, C.; Neustroev, V.; Nigro, C.; Nishijima, K.; Njoh Ekoume, T.; Noda, K.; Nozaki, S.; Ohtani, Y.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Persic, M.; Pihet, M.; Pirola, G.; Podobnik, F.; Prada Moroni, P. G.; Prandini, E.; Principe, G.; Priyadarshi, C.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Sahakyan, N.; Saito, T.; Satalecka, K.; Saturni, F. G.; Schleicher, B.; Schmidt, K.; Schmuckermaier, F.; Schubert, J. L.; Schweizer, T.; Sitarek, J.; Spolon, A.; Stamerra, A.; Strišković, J.; Strom, D.; Suda, Y.; Surić, T.; Suutarinen, S.; Tajima, H.; Takahashi, M.; Takeishi, R.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Ubach, S.; van Scherpenberg, J.; Ventura, S.; Verguilov, V.; Viale, I.; Vigorito, C. F.; Vitale, V.; Walter, R.; Yamamoto, T.; Ait Benkhali, F.; Becherini, Y.; Bi, B.; Böttcher, M.; Bolmont, J.; Brown, A.; Bulik, T.; Casanova, S.; Chand, T.; Chandra, S.; Chibueze, J.; Chibueze, O.; Egberts, K.; Einecke, S.; Ernenwein, J. -P.; Fontaine, G.; Gabici, S.; Goswami, P.; Holler, M.; Jamrozy, M.; Joshi, V.; Kasai, E.; Katarzyński, K.; Khatoon, R.; Khélifi, B.; Kluźniak, W.; Kosack, K.; Lang, R. G.; Le Stum, S.; Lemière, A.; Marx, R.; Moderski, R.; Moghadam, M. O.; de Naurois, M.; Niemiec, J.; O'Brien, P.; Ostrowski, M.; Peron, G.; Pita, S.; Pühlhofer, G.; Quirrenbach, A.; Rudak, B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schutte, H. M.; Seglar-Arroyo, M.; Shapopi, J. N. S.; Steenkamp, R.; Steppa, C.; Suzuki, H.; Tanaka, T.; Tluczykont, M.; Venter, C.; Wagner, S. J.; Wierzcholska, A.; Zdziarski, A. A.; Żywucka, N.; Becerra González, J.; Ciprini, S.; Venters, T. M.; D'Ammando, F.; Esteban-Gutiérrez, A.; Fallah Ramazani, V.; Filippenko, A. V.; Hovatta, T.; Jermak, H.; Jorstad, S.; Kiehlmann, S.; Lähteenmäki, A.; Larionov, V. M.; Larionova, E.; Marscher, A. P.; Morozova, D.; Max-Moerbeck, W.; Readhead, A. C. S.; Reeves, R.; Steele, I. A.; Tornikoski, M.; Verrecchia, F.; Xiao, H. B.; Zheng, W.OT 081 is a well-known, luminous blazar that is remarkably variable in many energy bands. We present the first broadband study
of the source, which includes very high energy (VHE, E > 100 GeV) γ -ray data taken by the MAGIC (Major Atmospheric
Gamma-ray Imaging Cherenkov telescopes) and H.E.S.S. (High Energy Stereoscopic System) imaging Cherenkov telescopes.
The discovery of VHE γ -ray emission happened during a high state of γ -ray activity in July 2016, observed by many instruments
from radio to VHE γ -rays. We identify fourstates of activity of the source, one of which includes VHE γ -ray emission. Variability
in the VHE domain is found on daily time-scales. The intrinsic VHE spectrum can be described by a power law with index
3.27 ± 0.44stat ± 0.15sys (MAGIC) and 3.39 ± 0.58stat ± 0.64sys (H.E.S.S.) in the energy range of 55–300 and 120–500 GeV,
respectively. The broadband emission cannot be successfully reproduced by a simple one-zone synchrotron self-Compton model.
Instead, an additional external Compton component is required. We test a lepto-hadronic model that reproduces the data set
well and a proton-synchrotron-dominated model that requires an extreme proton luminosity. Emission models that are able to
successfully represent the data place the emitting region well outside of the broad-line region to a location at which the radiative
environment is dominated by the infrared thermal radiation field of the dusty torus. In the scenario described by this flaring
activity, the source appears to be a flat spectrum radio quasar (FSRQ), in contrast with past categorizations. This suggests that
the source can be considered to be a transitional blazar, intermediate between BL Lac and FSRQ objects. © 2024 The Author(s).This work was supported in part by the Croatian Science Foundation under the project number IP-2022-10-4595.
MS-A was supported by the grant FJC2020-044895-I funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR.
HBX acknowledges the support from the National Natural Science Foundation of China (NSFC 12203034), the Shanghai Science and Technology Fund (22YF1431500), and the science research grants from the China Manned Space Project. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG, and HGF, the Italian INFN and INAF, the Swiss National Fund SNF, the grants PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, PID2019-105510GB-C31, PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, and PID2019-107988GB-C22 funded by MCIN/AEI 10.13039/501100011033, the Indian Department of Atomic Energy, the Japanese ICRR, the University of Tokyo, JSPS, and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-400/18.12.2020, and the Academy of Finland grant no. 320045 is gratefully acknowledged. This work was also been supported by Centros de Excelencia ‘Severo Ochoa’ y Unidades ‘María de Maeztu’ program of the MCIN/AEI 10.13039/501100011033 (SEV-2016-0588, SEV-2017-0709, CEX2019-000920-S, CEX2019-000918-M, and MDM-2015-0509-18-2) and by the CERCA institution of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2022-10-4595 and the University of Rijeka Project uniri-prirod-18-48; by the Deutsche Forschungsgemeinschaft (SFB1491 and SFB876); by the Polish Ministry Of Education and Science grant no. 2021/WK/08; and by the Brazilian MCTIC, CNPq, and FAPERJ.
The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the Helmholtz Association, the Alexander von Humboldt Foundation, the French Ministry of Higher Education, Research and Innovation, the Centre National de la Recherche Scientifique (CNRS/IN2P3 and CNRS/INSU), the Commissariat à l’énergie atomique et aux énergies alternatives (CEA), the U.K. Science and Technology Facilities Council (STFC), the Knut and Alice Wallenberg Foundation, the National Science Centre, Poland grant no. 2016/22/M/ST9/00382, the South African Department of Science and Technology and National Research Foundation, the University of Namibia, the National Commission on Research, Science & Technology of Namibia (NCRST), the Austrian Federal Ministry of Education, Science and Research and the Austrian Science Fund (FWF), the Australian Research Council (ARC), the Japan Society for the Promotion of Science, the University of Amsterdam, and the Science Committee of Armenia grant 21AG-1C085. We appreciate the excellent work of the technical support staff in Berlin, Zeuthen, Heidelberg, Palaiseau, Paris, Saclay, Tübingen, and in Namibia in the construction and operation of the equipment. This work benefited from services provided by the H.E.S.S. Virtual Organisation, supported by the national resource providers of the EGI Federation.
The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden.
Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work was performed in part under DOE Contract DE-AC02-76SF00515.
Part of this work is based on archival data, software, or online services provided by the Space Science Data Center ASI under contract ASI-INFN 2021-43-HH.0.
This research has made use of data from the OVRO 40-m monitoring program (Richards et al. 2011), supported by private funding from the California Institute of Technology and the Max Planck Institute for Radio Astronomy, and by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST-1109911.
SK acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 771282. WM-M gratefully acknowledges support by the ANID BASAL project FB210003 and FONDECYT 11190853. RR was supported by ANID BASAL grant FB210003. SC acknowledges support by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract ASI-OHBI-2017-12-I.0, with agreement ASI-INFN 2021-43-HH.0, and its Space Science Data Center (SSDC). This publication makes use of data obtained at the Metsähovi Radio Observatory, operated by the Aalto University. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.00856.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This research has made use of the TeVCat online source catalogue (http://tevcat.uchicago.edu). The research at Boston University was supported by NASA Fermi Guest Investigator grants 80NSSC17K0649 and 80NSSC20K1567. The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. Data from the Steward Observatory spectropolarimetric monitoring project were used. This program is supported by Fermi Guest Investigator grants NNX08AW56G, NNX09AU10G, NNX12AO93G, and NNX15AU81G. AVF and WZ received financial assistance from the Christopher R. Redlich Fund, as well as donations from Gary and Cynthia Bengier, Clark and Sharon Winslow, Alan Eustace (WZ is a Bengier–Winslow–Eustace Specialist in Astronomy), and numerous other donors. KAIT and its ongoing operation were made possible by donations from Sun Microsystems, Inc., the Hewlett-Packard Company, AutoScope Corporation, Lick Observatory, the U.S. National Science Foundation, the University of California, the Sylvia & Jim Katzman Foundation, and the TABASGO Foundation. Research at Lick Observatory is partially supported by a generous gift from Google. The authors wish to thank Matteo Cerruti (APC – Université Paris Cité and ICC – Universitat de Barcelona) for providing the numerical results for the hadronic and lepto-hadronic models used in this work.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (SEV-2016-0588).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (SEV-2017-0709).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000920-S).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000918-M).Peer reviewe
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