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1. The case of the missing VHE GRBs: A retrospective study of Swift gamma-ray bursts with Imaging Atmospheric Cherenkov Telescopes

Author

Ashkar, Halim, Sangaré, Aurélie, Fegan, Stephen, Mbarubucyeye, Jean Damascene, Ruiz-Velasco, Edna, and Zhu, Sylvia J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Gamma-ray bursts (GRBs) are particle acceleration sites that can emit photons in the very high-energy (VHE) domain through non-thermal processes. From 2004 until 2018, the current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) did not detect any GRB in the VHE domain. However, from 2018 to 2020, five detections have been reported. In this work, we try to solve the case of the missing VHE GBRs prior to 2018. We aim to identify GRBs that might have eluded VHE detection in the past years by the H.E.S.S., MAGIC, and VERITAS IACTs. To do so, we study GRBs with known redshift detected by \emph{Swift} from 2004 until June 2022. We first identify all GRBs that could have been observed by these IACTs since 2004, considering observation conditions and visibility constraints. We assume a relation between the X-rays and the VHE gamma rays based on the VHE GRBs detected to date and combine this with the redshift measurements, instrument response information, and observation conditions to predict the observed VHE gamma-ray flux from the \emph{Swift}-XRT measurements. We report findings on 12 bright low-redshift GRBs that we identify as most likely to have been detected in the VHE domain by current IACTs. The rate of IACT-detectable GRBs with ideal observation conditions is $<$1 VHE GRB per year with the current configuration. With its lower energy threshold and higher sensitivity, this rate increases to $\sim$4 VHE GRBs per year with CTA., Comment: Submitted to ApJS

Published
2024

2. Chasing Gravitational Waves with the Cherenkov Telescope Array

Author

Green, Jarred Gershon, Carosi, Alessandro, Nava, Lara, Patricelli, Barbara, Schüssler, Fabian, Seglar-Arroyo, Monica, Consortium, Cta, Abe, Kazuki, Abe, Shotaro, Acharyya, Atreya, Adam, Remi, Aguasca-Cabot, Arnau, Agudo, Ivan, Alfaro, Jorge, Alvarez-Crespo, Nuria, Batista, Rafael Alves, Amans, Jean-Philippe, Amato, Elena, Ambrosino, Filippo, Angüner, Ekrem Oguzhan, Antonelli, Lucio Angelo, Aramo, Carla, Arcaro, Cornelia, Arrabito, Luisa, Asano, Katsuaki, Aschersleben, Jann, Ashkar, Halim, Stuani, Luiz Augusto, Baack, Dominik, Backes, Michael, Balazs, Csaba, Balbo, Matteo, Larriva, Andres Baquero, Martins, Victor Barbosa, de Almeida, Ulisses Barres, Barrio, Juan Abel, Bastieri, Denis, Batista, Pedro Ivo, Batković, Ivana, Batzofin, Rowan William, Baxter, Joshua Ryo, Beck, Geoffrey, Tjus, Julia Becker, Beiske, Lukas, Belardinelli, Daniele, Benbow, Wystan, Bernardini, Elisa, Medrano, Juan Bernete, Bernlöhr, Konrad, Berti, Alessio, Beshley, Vasyl, Bhattacharjee, Pooja, Bhattacharyya, Saptashwa, Bi, Baiyang, Biederbeck, Noah, Biland, Adrian, Bissaldi, Elisabetta, Blanch, Oscar, Blazek, Jiri, Boisson, Catherine, Bolmont, Julien, Bonnoli, Giacomo, Bordas, Pol, Bošnjak, Željka, Bradascio, Federica, Braiding, Catherine, Bronzini, Ettore, Brose, Robert, Brown, Anthony M., Brun, Francois, Brunelli, Giulia, Bulgarelli, Andrea, Burelli, Irene, Burmistrov, Leonid, Burton, Michael, Bylund, Tomas, Calisse, Paolo Gherardo, Campoy-Ordaz, Anna, Cantlay, Brandon Khan, Capalbi, Milvia, Caproni, Anderson, Capuzzo-Dolcetta, Roberto, Carlile, Colin, Caroff, Sami, Carosi, Roberto, Carrasco, Marie-Sophie, Cascone, Enrico, Cassol, Franca, Castrejon, Noelia, Catalani, Fernando, Cerasole, Davide, Cerruti, Matteo, Chaty, Sylvain, Chen, Andrew W, Chernyakova, Maria, Chiavassa, Andrea, Chudoba, Jiří, Araujo, Carlos Henrique Coimbra, Conforti, Vito, Conte, Francesco, Contreras, Jose Luis, Cossou, Christophe, Costa, Alessandro, Costantini, Heide, Cristofari, Pierre, Cuevas, Omar, Curtis-Ginsberg, Zachary, D'Amico, Giacomo, D'Ammando, Filippo, Dadina, Mauro, Dalchenko, Mykhailo, David, Ludovic, Davids, Isak Delberth, Dazzi, Francesco, De Angelis, Alessandro, de Lavergne, Mathieu de Bony, De Caprio, Vincenzo, De Cesare, Giovanni, Pino, Elisabete M. de Gouveia Dal, De Lotto, Barbara, de Lucia, Mario, de Menezes, Raniere, de Naurois, Mathieu, Wilhelmi, Emma de Oña, De Simone, Nicola, de Souza, Vitor, Del Peral, Luis, del Valle, Maria Victoria, Delagnes, Eric, Giler, Andres Gabriel Delgado, Delgado, Carlos, Dell'aiera, Michael, Della Ceca, Roberto, Della Valle, Massimo, Della Volpe, Domenico, Depaoli, Davide, Dettlaff, Antonios, Di Girolamo, Tristano, Di Piano, Ambra, Di Pierro, Federico, Di Tria, Riccardo, Di Venere, Leonardo, Díaz-Bahamondes, Christian, Dib, Claudio, Diebold, Sebastian, Dima, Razvan, Dinesh, Adithiya, Djannati-Ataï, Arache, Djuvsland, Julia Isabel, Dominguez, Alberto, Dominik, Rune Michael, Donini, Alice, Dorner, Daniela, Dörner, Julien, Doro, Michele, Anjos, Rita de Cassia dos, Dournaux, Jean-Laurent, Dravins, Dainis, Duangchan, Chaimongkol, Dubos, Coline, Ducci, Lozenzo, Dwarkadas, Vikram V., Ebr, Jan, Eckner, Christopher, Egberts, Kathrin, Einecke, Sabrina, Elsässer, Dominik, Emery, Gabriel, Godoy, Miguel Escobar, Escudero, Juan, Esposito, Paolo, Falceta-Gonçalves, Diego, Ramazani, Vandad Fallah, Faure, Alice, Fedorova, Elena, Fegan, Stephen, Feijen, Kirsty, Feng, Qi, Ferrand, Gilles, Ferrarotto, Fabio, Fiandrini, Emanuele, Fiasson, Armand, Fioretti, Valentina, Foffano, Luca, Guiteras, Lluis Font, Fontaine, Gerard, Fröse, Stefan, Fukami, Satoshi, Fukui, Yasuo, Funk, Stefan, Gaggero, Daniele, Galanti, Giorgio, Galaz, Gaspar, Gallant, Yves A., Gallozzi, Stefano, Gammaldi, Viviana, Gasbarra, Claudio, Gaug, Markus, Ghalumyan, Arsen, Gianotti, Fulvio, Giarrusso, Marina, Giglietto, Nicola, Giordano, Francesco, Giuliani, Andrea, Glicenstein, Jean-Francois, Glombitza, Jonas, Goldoni, Paolo, González, José Mauricio, González, Maria Magdalena, Coelho, Jaziel Goulart, Granot, Jonathan, Grasso, Dario, Haro, Roger Grau, Green, David, Greenshaw, Tim, Grolleron, Guillaume, Grube, Jeff, Gueta, Orel, Gunji, Shuichi, Hadasch, Daniela, Hamal, Petr, Hanlon, William, Hara, Satoshi, Harvey, Violet M., Hashiyama, Kazuaki, Hassan, Tarek, Heller, Matthieu, Cadena, Sergio Hernández, Hie, Jonathan, Hiroshima, Nagisa, Hnatyk, Bohdan, Hnatyk, Roman, Hoffmann, Dirk, Hofmann, Werner, Holler, Markus, Horan, Deirdre, Horvath, Pavel, Hovatta, Talvikki, Hrupec, Dario, Hussain, Saqib, Iarlori, Marco, Inada, Tomohiro, Incardona, Federico, Inome, Yusuke, Inoue, Susumu, Iocco, Fabio, Ishio, Kazuma, Jamrozy, Marek, Janecek, Petr, Jankowsky, Felix, Jarnot, Christian, Jean, Pierre, Martínez, Irene Jiménez, Jin, Weidong, Jocou, Laurent, Juramy-Gilles, Claire, Jurysek, Jakub, KALEKIN, Oleg, Kantzas, Dimitrios, Karas, Vladimir, Kaufmann, Sarah, Kerszberg, Daniel, Khelifi, Bruno, Kieda, David B, Kleiner, Tobias Kai, Kluźniak, Włodzimierz, Kobayashi, Yukiho, Kohri, Kazunori, Komin, Nukri, Kornecki, Paula, Kosack, Karl, Kubo, Hidetoshi, Kushida, Junko, La Barbera, Antonino, La Palombara, Nicola, Lainez, Maria, Lamastra, Alessandra, Lapington, Jon S, Lazarevic, Sanja, Lazendic-Galloway, Jasmina, Leach, Steven, Lemoine-Goumard, Marianne, Lenain, Jean-Philippe, Leto, Giuseppe, Leuschner, Fabian, Lindfors, Elina, Linhoff, Maximilian, Liodakis, Ioannis, Loïc, Lozach, Lombardi, Saverio, Longo, Francesco, López-Coto, Rubén, López-Moya, Marcos, López-Oramas, Alicia, Loporchio, Serena, Bahilo, Julio Lozano, Luque-Escamilla, Pedro L., Macias, Oscar, Maier, Gernot, Majumdar, Pratik, Malyshev, Denys, Malyshev, Dmitry, Mandat, Dusan, Manicò, Giulio, Marinos, Peter David, Markoff, Sera, Márquez, Isabel, Marquez, Patricia, Marsella, Giovanni, Martí, Josep, Martin, Pierrick, Martínez, Gustavo Augusto, Martínez, Manel, Martinez, Oibar, Marty, Christophe, Mas-Aguilar, Alvaro, Mastropietro, Michele, Maurin, Gilles, Max-Moerbeck, Walter, Mazin, Daniel, Melkumyan, David, Menchiari, Stefano, Mestre, Enrique, Meunier, Jean-Luc, Meyer, Dominique M. -A., Miceli, Davide, Michailidis, Miltiadis, Michałowski, Jerzy, Miener, Tjark, Miranda, Jose Miguel, Mitchell, Alison, Mizote, Masaya, Mizuno, Tsunefumi, Moderski, Rafal, Mohrmann, Lars, Molero, Miguel, Molfese, Cesare, Molina, Edgar, Montaruli, Teresa, Moralejo, Abelardo, Morcuende, Daniel, Morik, Katharina, Morselli, Aldo, Moulin, Emmanuel, Zamanillo, Victor Moya, Mukherjee, Reshmi, Munari, Kevin, Muraczewski, Adam, Muraishi, Hiroshi, Nakamori, Takeshi, Nayak, Amrit, Nemmen, Rodrigo, Nickel, Lukas, Niemiec, Jacek, Nieto, Daniel, Rosillo, Mireia Nievas, Nikołajuk, Marek, Nishijima, Kyoshi, Noda, Koji, Nosek, Dalibor, Novosyadlyj, Bohdan, Novotný, Vladimír, Nozaki, Seiya, O'Brien, Paul, Ohishi, Michiko, Ohtani, Yoshiki, Okumura, Akira, Olive, Jean-François, Olmi, Barbara, Ong, Rene A., Orienti, Monica, Orito, Reiko, Orlandini, Mauro, Orlando, Elena, Ostrowski, Michal, Otte, Nepomuk, Oya, Igor, Pagano, Isabella, Pagliaro, Antonio, Palatiello, Michele, Panebianco, Gabriele, Paredes, Josep M., Parmiggiani, Nicolò, Patel, Sonal Ramesh, Pavlović, Dijana, Pe'er, Asaf, Pech, Miroslav, Pecimotika, Mario, Peresano, Michele, Pérez-Romero, Judit, Peron, Giada, Persic, Massimo, Petrucci, Pierre-Olivier, Petruk, Oleh, Pfeifle, Felix, Pintore, Fabio, Pirola, Giorgio, Pittori, Carlotta, Plard, Cyann, Podobnik, Franjo, Pohl, Martin, Pons, Estelle, Prandini, Elisa, Prast, Julie, Principe, Giacomo, Priyadarshi, Chaitanya, Produit, Nicolas, Prokhorov, Dmitry, Pueschel, Elisa, Pühlhofer, Gerd, Pumo, Maria Letizia, Punch, Michael, Quirrenbach, Andreas, Raino, Silvia, Randazzo, Nunzio, Rando, Riccardo, Ravel, Thierry, Razzaque, Soebur, Regeard, Maxime, Reichherzer, Patrick, Reimer, Anita, Reimer, Olaf, Reisenegger, Andreas, Reposeur, Thierry, Reville, Brian, Rhode, Wolfgang, Ribó, Marc, Richtler, Tom, Rieger, Frank, Roache, Emmet, Fernandez, Gonzalo Rodriguez, Frías, Maria Dolores Rodríguez, Rodríguez-Vázquez, Juan José, Romano, Patrizia, Romeo, Giuseppe, Rosado, Jaime, Rowell, Gavin P, Rudak, Bronislaw, Ruiter, Ashley J., Rulten, Cameron Boyd, Russo, Federico, Sadeh, Iftach, Saha, Lab, Saito, Takayuki, Sakurai, Shunsuke, Salzmann, Heiko, Sanchez, David, Sanchez-Conde, Miguel, Sangiorgi, Pierluca, Sano, Hidetoshi, Santander, Marcos, Santangelo, Andrea, Santos-Lima, Reinaldo, Sanuy, Andreu, Šarić, Toni, Sarkar, Arkadipta, Sarkar, Subir, Saturni, Francesco Gabriele, Savchenko, Volodymyr, Scherer, Andres, Schipani, Pietro, Schleicher, Bernd, Schovanek, Petr, Schubert, Jan Lukas, Schwanke, Ullrich, Schwefer, Georg, Scuderi, Salvatore, Arroyo, Monica Seglar, Seitenzahl, Ivo, Sergijenko, Olga, Sguera, Vito, Shang, Ruo-Yu, Sharma, Pooja, Sidibe, Guereguin Der Sylvestre, Sidoli, Lara, Siejkowski, Hubert, Siqueira, Clarissa, Sizun, Patrick, Sliusar, Vitalii, Slowikowska, Agnieszka, Sol, Helene, Specovius, Andreas, Spencer, Samuel Timothy, Spiga, Daniele, Stamerra, Antonio, Stanič, Samo, Starecki, Tomasz, Starling, Rhaana, Steppa, Constantin, Stolarczyk, Thierry, Strišković, Jelena, Strzys, Marcel C., Suda, Yusuke, Suomijarvi, Tiina, Tak, Donggeun, Takahashi, Mitsunari, Takeishi, Ryuji, Tam, Pak-Hin Thomas, Tanaka, Shuta J, Tanaka, Takaaki, Terauchi, Kenta, Testa, Vincenzo, Tibaldo, Luigi, Tibolla, Omar, Torradeflot, Francesc, Torres, Diego F., Torresi, Eleonora, Tothill, Nick, Toussenel, Francois, Touzard, Victoria, Tramacere, Andrea, Travnicek, Petr, Tripodo, Giovanni, Truzzi, Stefano, Tsiahina, Adellain, Tutone, Antonio, Vacula, Martin, Vallage, Bertrand, Vallania, Piero, Vallés, Ramon, van Eldik, Christopher, van Scherpenberg, Juliane, Vandenbroucke, Justin, Vassiliev, Vladimir, Venault, Philippe, Ventura, Sofia, Vercellone, Stefano, Verna, Gaia, Viana, Aion, Viaux, Nicolás, Vigliano, Alessandro, Vignatti, Jonatan, Vigorito, Carlo francesco, Vitale, Vincenzo, Vodeb, Veronika, Voisin, Vincent, Vorobiov, Serguei, Voutsinas, Georgios Gerasimos, Vovk, Ievgen, Waegebaert, Vincent, Wagner, Stefan Joachim, Walter, Roland, Ward, Martin, Wechakama, Maneenate, White, Richard, Wierzcholska, Alicja, Will, Martin, Williams, David A., Wohlleben, Frederik, Wolter, Anna, Yamamoto, Tokonatsu, Yamazaki, Ryo, Yang, Lili, Yoshida, Tatsuo, Yoshikoshi, Takanori, Zacharias, Michael, Sanchez, Ricardo Zanmar, Zavrtanik, Danilo, Zavrtanik, Marko, Zdziarski, Andrzej A., Zech, Andreas, Zhdanov, Valery I., Ziȩtara, Krzysztof, Živec, Miha, and Zuriaga-Puig, Jaume

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The 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., Comment: Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)

Published
2023

3. Probing VHE gamma-ray emission from GW events with H.E.S.S

Author

Ashkar, Halim, de Lavergne, Mathieu de Bony, Brun, Francois, Fegan, Stephen, Konno, Ruslan, Ohm, Stefan, Prokoph, Heike, Schüssler, Fabian, and Zhu, Sylvia J

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

Gravitational wave (GW) events, particularly those connected to the merger of compact objects such as neutron stars, are believed to be the primary source of short gamma-ray bursts. To explore the very high energy (VHE) component of the emission from these events, the H.E.S.S. collaboration has dedicated a substantial effort and observing time to follow up on these events. During the second and third GW observing runs, H.E.S.S. was the first ground-based instrument to observe the GW170817 binary neutron star merger. In addition, H.E.S.S. followed four binary black hole mergers. The data acquired by H.E.S.S. was used to constrain the VHE emission from these events for the first time. H.E.S.S. also monitored the GW170817 source for approximately 50 hours and obtained limits that constrained the magnetic field in the merger remnant to $> 24 \mu G$. As the fourth GW observing run (O4) approaches, the H.E.S.S. collaboration has allocated significant observation time to the follow-up of GW events. This contribution provides an overview of the science results derived from the H.E.S.S. follow-up of GW events, a technical overview of the GW follow-up strategies for O4, and an update on H.E.S.S. activities during O4., Comment: Proceedings 38th International Cosmic Ray Conference (ICRC2023)

Published
2023

4. All sky archival search for FRB high energy counterparts with Swift and Fermi

Author

Ashkar, Halim, Bouhaddouti, Mehdi El, Fegan, Stephen, and Schüssler, Fabian

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Fast radio bursts (FRBs) are millisecond-duration radio signals from unknown cosmic origin. Many models associate FRBs with high-energy astrophysical objects such as magnetars. In this attempt to find counterparts to FRBs, we explore gamma-ray bursts (GRBs) from the Swift and Fermi missions. We first search for spatial correlations between FRB and GRB populations as a whole and then search for a one-by-one correlation between each of the FRBs and GRBs investigated. Temporal coincidences are not considered. To evaluate the significance of any correlation found, we generate background realizations that take into account instrumentally induced anisotropies in the distribution of the sources. Neither study yields any significant counterpart detection. We estimate that less than 4\% of the FRBs are associated with GRBs in the studied samples, Comment: Proceedings 38th International Cosmic Ray Conference (ICRC2023)

Published
2023

5. The Third Fermi Large Area Telescope Catalog of Gamma-ray Pulsars

Author

Smith, David A., Bruel, Philippe, Clark, Colin J., Guillemot, Lucas, Kerr, Matthew T., Ray, Paul, Abdollahi, Soheila, Ajello, Marco, Baldini, Luca, Ballet, Jean, Baring, Matthew, Bassa, Cees, Gonzalez, Josefa Becerra, Bellazzini, Ronaldo, Berretta, Alessandra, Bhattacharyya, Bhaswati, Bissaldi, Elisabetta, Bonino, Raffaella, Bottacini, Eugenio, Bregeon, Johan, Burgay, Marta, Burnett, Toby, Cameron, Rob, Camilo, Fernando, Caputo, Regina, Caraveo, Patrizia, Cavazzuti, Elisabetta, Chiaro, Graziano, Ciprini, Stefano, Cognard, Ismael, Orestano, Paolo Cristarella, Crnogorcevic, Milena, Cuoco, Alessandro, Cutini, Sara, D'Ammando, Filippo, de Angelis, Alessandro, De Gaetano, Salvatore, de Menezes, Raniere, de Palma, Francesco, DeCesar, Megan, Deneva, Julia, Di Lalla, Niccola, Di Venere, Leonardo, Dirirsa, Feraol Fana, Dominguez, Alberto, Dumora, Denis, Fegan, Stephen, Ferrara, Elizabeth, Fiori, Alessio, Fleischhack, Henrike, Flynn, Chris, Franckowiak, Anna, Freire, Paulo, Fukazawa, Yasushi, Fusco, Piergiorgio, Galanti, Giorgio, Gammaldi, Viviana, Gargano, Fabio, Gasparrini, Dario, Giacchino, Federica, Giglietto, Nico, Giordano, Francesco, Giroletti, Marcello, Green, David, Grenier, Isabelle, Guiriec, Sylvain, Gustafsson, Michael, Harding, Alice, Hays, Liz, Hewitt, John, Horan, Deirdre, Hou, Xian, Jankowski, Fabian, Johnson, Tyrel, Johnson, Robert, Johnston, Simon, Kataoka, Jun, Keith, Michael J., Kramer, Michael, Kuss, Michael, Latronico, Luca, Lee, Shiu-Hang, Li, Di, Li, Jian, Limyansky, Brent, Longo, Francesco, Loparco, Francesco, Lorusso, Leonarda, Lovellette, Michael, Lower, Marcus, Lubrano, Pasquale, Lyne, Andrew, Maldera, Simone, Manchester, Richard, Manfreda, Alberto, Marelli, Martino, Marta-Devesa, Guillem, Mazziotta, Mario Nicola, McEnery, Julie, Mereu, Isabella, Michelson, Peter, Mitthumsiri, Warit, Mizuno, Tsunefumi, Moiseev, Alex, Monzani, Maria Elena, Morselli, Aldo, Negro, Michela, Nemmen, Rodrigo, Nieder, Lars, Nuss, Eric, Omodei, Nicola, Orienti, Monica, Orlando, Elena, Ormes, Jonathan F., Palatiello, Michele, Paneque, David, Panzarini, Giuliana, Persic, Massimo, Pesce-Rollins, Melissa, Pillera, Roberta, Poon, Helen, Porter, Troy, Principe, Giacomo, Raino, Silvia, Rando, Riccardo, Ransom, Scott, Razzano, Massimiliano, Razzaque, Soebur, Reimer, Anita, Reimer, Olaf, Renault-Tinacci, Nicolas, Romani, Roger, Sanchez-Conde, Miguel A., Parkinson, Pablo Saz, Scotton, Lorenzo, Serini, Davide, Sgro, Carmelo, Shannon, Ryan, Sharma, Vidushi, Siskind, Eric J., Spandre, Gloria, Spinelli, Paolo, Stappers, Ben, Stephens, Tom, Suson, Dan, Tajima, Hiro, Tak, Dongguen, Theureau, Gilles, Thompson, David, Tibolla, Omar, Torres, Diego F., Valverde, Janeth, Venter, Christo, Wadiasingh, Zorawar, Wang, Nina, Wang, Pei, Weltevrede, Patrick, Wood, Kent, and Zaharijas, Gabrijela

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems co-located with LAT sources also likely harbor gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and candidates, 10% of all known pulsars, compared to $\leq 11$ known before Fermi. Half of the gamma-ray pulsars are young. Of these, the half that are undetected in radio have a broader Galactic latitude distribution than the young radio-loud pulsars. The others are MSPs, with 6 undetected in radio. Overall, >235 are bright enough above 50 MeV to fit the pulse profile, the energy spectrum, or both. For the common two-peaked profiles, the gamma-ray peak closest to the magnetic pole crossing generally has a softer spectrum. The spectral energy distributions tend to narrow as the spindown power $\dot E$ decreases to its observed minimum near $10^{33}$ erg s$^{-1}$, approaching the shape for synchrotron radiation from monoenergetic electrons. We calculate gamma-ray luminosities when distances are available. Our all-sky gamma-ray sensitivity map is useful for population syntheses. The electronic catalog version provides gamma-ray pulsar ephemerides, properties and fit results to guide and be compared with modeling results., Comment: 142 pages. Accepted by the Astrophysical Journal Supplement

Published
2023

6. Design and Performance of the Prototype Schwarzschild-Couder Telescope Camera

Author

Adams, Colin B., Ambrosi, Giovanni, Ambrosio, Michelangelo, Aramo, Carla, Arlen, Timothy, Benbow, Wystan, Bertucci, Bruna, Bissaldi, Elisabetta, Biteau, Jonathan, Bitossi, Massimiliano, Boiano, Alfonso, Bonavolontà, Carmela, Bose, Richard, Bouvier, Aurelien, Buscemi, Mario, Brill, Aryeh, Brown, Anthony M., Buckley, James H., Canestrari, Rodolfo, Capasso, Massimo, Caprai, Mirco, Coppi, Paolo, Covault, Corbin E., Depaoli, Davide, Di Venere, Leonardo, Errando, Manel, Fegan, Stephen, Feng, Qi, Fiandrini, Emanuele, Furniss, Amy, Garczarczyk, Markus, Gent, Alasdair, Giglietto, Nicola, Giordano, Francesco, Giro, Enrico, Halliday, Robert, Hervet, Olivier, Hughes, Gareth, Incardona, Simone, Humensky, Thomas B., Ionica, Maria, Jin, Weidong, Johnson, Caitlin A., Kieda, David, Krennrich, Frank, Kuznetsov, Andrey, Lapington, Jon, Licciulli, Francesco, Loporchio, Serena, Marsella, Giovanni, Masone, Vincenzo, Meagher, Kevin, Meures, Thomas, Mode, Brent A. W., Mognet, Samuel A. I., Mukherjee, Reshmi, Okumura, Akira, Pantaleo, Francesca R., Paoletti, Riccardo, Di Pierro, Federico, Ribeiro, Deivid, Riitano, Luca, Roache, Emmet, Ross, Duncan, Rousselle, Julien, Rugliancich, Andrea, Santander, Marcos, Schneider, Michael, Schoorlemmer, Harm, Shang, Ruo-Yu, Stevenson, Brandon, Stiaccini, Leonardo, Tajima, Hiroyasu, Taylor, Leslie P., Thornhill, Julian, Tosti, Luca, Tripodo, Giovanni, Vagelli, Valerio, Valentino, Massimo, Vandenbroucke, Justin, Vassiliev, Vladimir V., Wakely, Scott P., Watson, Jason J., White, Richard, Wilcox, Patrick, Williams, David A., Wood, Matthew, Yu, Peter, and Zink, Adrian

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

The prototype Schwarzschild-Couder Telescope (pSCT) is a candidate for a medium-sized telescope in the Cherenkov Telescope Array. The pSCT is based on a novel dual mirror optics design which reduces the plate scale and allows for the use of silicon photomultipliers as photodetectors. The prototype pSCT camera currently has only the central sector instrumented with 25 camera modules (1600 pixels), providing a 2.68$^{\circ}$ field of view (FoV). The camera electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application specific integrated circuits. Field programmable gate arrays sample incoming signals at a gigasample per second. A single backplane provides camera-wide triggers. An upgrade of the pSCT camera is in progress, which will fully populate the focal plane. This will increase the number of pixels to 11,328, the number of backplanes to 9, and the FoV to 8.04$^{\circ}$. Here we give a detailed description of the pSCT camera, including the basic concept, mechanical design, detectors, electronics, current status and first light.

Published
2022
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7. Incremental Fermi Large Area Telescope Fourth Source Catalog

Author

collaboration, Fermi-LAT, Abdollahi, Soheila, Acero, Fabio, Baldini, Luca, Ballet, Jean, Bastieri, Denis, Bellazzini, Ronaldo, Berenji, Bijan, Berretta, Alessandra, Bissaldi, Elisabetta, Blandford, Roger D., Bloom, Elliott, Bonino, Raffaella, Brill, Ari, Britto, Richard J., Bruel, Philippe, Burnett, Toby H., Buson, Sara, Cameron, Rob A., Caputo, Regina, Caraveo, Patrizia A., Castro, Daniel, Chaty, Sylvain, Cheung, Teddy C., Chiaro, Graziano, Cibrario, Nicolo, Ciprini, Stefano, Coronado-Blazquez, Javier, Crnogorcevic, Milena, Cutini, Sara, D'Ammando, Filippo, De Gaetano, Salvatore, Digel, Seth W., Di Lalla, Niccolo, Dirirsa, Feraol F., Di Venere, Leonardo, Dominguez, Alberto, Ramazani, Vandad Fallah, Fegan, Stephen J., Ferrara, Elizabeth C., Fiori, Alessio, Fleischhack, Henrike, Franckowiak, Anna, Fukazawa, Yasushi, Funk, Stefan, Fusco, Piergiorgio, Galanti, Giorgio, Gammaldi, Viviana, Gargano, Fabio, Garrappa, Simone, Gasparrini, Dario, Giacchino, Federica, Giglietto, Nico, Giordano, Francesco, Giroletti, Marcello, Glanzman, Thomas, Green, David, Grenier, Isabelle A., Grondin, Marie-Helene, Guillemot, Lucas, Guiriec, Sylvain, Gustafsson, Michael, Harding, Alice K., Hays, Liz, Hewitt, John W., Horan, Deirdre, Hou, Xian, Johannesson, Gudlaugur, Karwin, Christopher M., Kayanoki, Taishu, Kerr, Matthew T., Kuss, Michael, Landriu, David, Larsson, Stefan, Latronico, Luca, Lemoine-Goumard, Marianne, Li, Jian, Liodakis, Ioannis, Longo, Francesco, Loparco, Francesco, Lott, Benoit, Lubrano, Pasquale, Maldera, Simone, Malyshev, Dmitry, Manfreda, Alberto, Marti-Devesa, Guillem, Mazziotta, Mario N., Mereu, Isabella, Meyer, Manuel, Michelson, Peter F., Mirabal, Nestor, Mitthumsiri, Warit, Mizuno, Tsunefumi, Moiseev, Alex A., Monzani, Maria E., Morselli, Aldo, Moskalenko, Igor V., Negro, Michela, Nuss, Eric, Omodei, Nicola, Orienti, Monica, Orlando, Elena, Paneque, David, Pei, Zhiyuan, Perkins, Jeremy S., Persic, Massimo, Pesce-Rollins, Melissa, Petrosian, Vahe, Pillera, Roberta, Poon, Helen, Porter, Troy A., Principe, Giacomo, Raino, Silvia, Rando, Riccardo, Rani, Bindu, Razzano, Massimiliano, Razzaque, Soebur, Reimer, Anita, Reimer, Olaf, Reposeur, Thierry, Sanchez-Conde, Miguel A., Parkinson, Pablo M. Saz, Scotton, Lorenzo, Serini, Davide, Sgro, Carmelo, Siskind, Eric J., Smith, David A., Spandre, Gloria, Spinelli, Paolo, Sueoka, Kohei, Suson, Dan J., Tajima, Hiro, Tak, Dongguen, Thayer, Jana B., Thompson, David J., Torres, Diego F., Troja, Eleonora, Valverde, Janeth, Wood, Kent, and Zaharijas, Gabrijela

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of gamma-ray sources. Based on the first twelve years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources., Comment: accepted in ApJS; follow-up paper to 1902.10045

Published
2022
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8. A decade of multi-wavelength observations of the TeV blazar 1ES 1215+303: Extreme shift of the synchrotron peak frequency and long-term optical-gamma-ray flux increase

Author

Valverde, Janeth, Horan, Deirdre, Bernard, Denis, Fegan, Stephen, Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brill, A., Brose, R., Buchovecky, M., Buckley, J. H., Christiansen, J. L., Cui, W., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Gent, A., Gillanders, G. H., Giuri, C., Gueta, O., Hanna, D., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kelley-Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Lang, M. J., Maier, G., Moriarty, P., Mukherjee, R., Nieto, D., Nievas-Rosillo, M., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pfrang, K., Pichel, A., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Richards, G. T., Roache, E., Sadeh, I., Santander, M., Scott, S. S., Sembroski, G. H., Shahinyan, K., Shang, R., Sushch, I., Vassiliev, V. V., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J, Noto, Giuliana, Edwards, P. G., Piner, B. G., Ramazani, V. Fallah, Hovatta, T., Jormanainen, J., Lindfors, E., Nilsson, K., Takalo, L., Kovalev, Y. Y., Lister, M. L., Pushkarev, A. B., Savolainen, T., Kiehlmann, S., Max-Moerbeck, W., Readhead, A. C. S., Lähteenmäki, A., and Tornikoski, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and VERITAS, we present an extensive study of the long-term multi-wavelength radio-to-gamma-ray flux-density variability, with the addition of a couple of short-time radio-structure and optical polarization observations of the blazar 1ES 1215+303 (z=0.130), with a focus on its gamma-ray emission from 100 MeV to 30 TeV. Multiple strong GeV gamma-ray flares, a long-term increase in the gamma-ray and optical flux baseline and a linear correlation between these two bands are observed over the ten-year period. Typical HBL behaviors are identified in the radio morphology and broadband spectrum of the source. Three stationary features in the innermost jet are resolved by VLBA at 43.1, 22.2, and 15.3 GHz. We employ a two-component synchrotron self-Compton model to describe different flux states of the source, including the epoch during which an extreme shift in energy of the synchrotron peak frequency from infrared to soft X-rays is observed., Comment: Accepted for publication in the Astrophysical Journal

Published
2020
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9. Design and characterization of a single photoelectron calibration system for the NectarCAM camera of the medium-sized telescopes of the Cherenkov Telescope Array

Author

Biasuzzi, Barbara, Pressard, Kevin, Biteau, Jonathan, Geoffroy, Brice, Goncalves, Carlos Domingues, Hull, Giulia, Imre, Miktat, Josselin, Michael, Maroni, Alain, Mathon, Bernard, Seminor, Lucien, Suomijarvi, Tiina, Trung, Thi Nguyen, Vatrinet, Laurent, Brun, Patrick, Caroff, Sami, Fegan, Stephen, Ferreira, Oscar, Jean, Pierre, Karkar, Sonia, Olive, Jean-François, Rivoire, Stéphane, Sizun, Patrick, Thiant, Floris, Tsiahina, Adellain, Toussenel, François, and Vasileiadis, Georges

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

In this work, we describe the optical properties of the single photoelectron (SPE) calibration system designed for NectarCAM, a camera proposed for the Medium Sized Telescopes (MST) of the Cherenkov Telescope Array (CTA). One of the goals of the SPE system, as integral part of the NectarCAM camera, consists in measuring with high accuracy the gain of its photo-detection chain. The SPE system is based on a white painted screen where light pulses are injected through a fishtail light guide from a dedicated flasher. The screen - placed 15 mm away from the focal plane - is mounted on an XY motorization that allows movements over all the camera plane. This allows in-situ measurements of the SPE spectra via a complete scan of the 1855 photo-multiplier tubes (PMTs) of NectarCAM. This calibration process will enable the reduction of the systematic uncertainties on the energy reconstruction of $\gamma$-rays coming from distant astronomical sources and detected by CTA.

Published
2019
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10. Using Muon Rings for the Optical Throughput Calibration of the Cherenkov Telescope Array

Author

Gaug, Markus, Fegan, Stephen, Mitchell, Alison, Maccarone, Maria-Concetta, Mineo, Teresa, and Okumura, Akira

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Muon ring images observed with Imaging Atmospheric Cherenkov Telescopes (IACTs) provide a powerful means to calibrate the optical throughput of IACTs and monitor their optical point spread function. We investigate whether muons ring images can be used as the primary optical throughput calibration method for the telescopes of the future Cherenkov Telescope Array (CTA) and find several additional systematic effects in comparison to previous works. To ensure that the method achieves the accuracy required by CTA, these systematic effects need to be taken into account and minor modifications to the hardware and analysis are necessary. We derive analytic estimates for the expected muon data rates to be used for optical throughput calibration, monitoring of the optical point spread function, with achievable statistical and systematic uncertainties, and explore the potential of muon ring images as a secondary method of camera pixel flat-fielding., Comment: Proceedings of the 36th International Cosmic Ray Conference, Madison, Wisconsin

Published
2019

11. Constraints on the Intergalactic Magnetic Field with Gamma-Ray Observations of Blazars

Author

Finke, Justin D., Reyes, Luis C., Georganopoulos, Markos, Reynolds, Kaeleigh, Ajello, Marco, Fegan, Stephen J., and McCann, Kevin

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Distant BL Lacertae objects emit $\gamma$ rays which interact with the extragalactic background light (EBL), creating electron-positron pairs, and reducing the flux measured by ground-based imaging atmospheric Cherenkov telescopes (IACTs) at very-high energies (VHE). These pairs can Compton-scatter the cosmic microwave background, creating a $\gamma$-ray signature at slightly lower energies observable by the \fermi\ Large Area Telescope (LAT). This signal is strongly dependent on the intergalactic magnetic field (IGMF) strength ($B$) and its coherence length ($L_B$). We use IACT spectra taken from the literature for 5 VHE-detected BL Lac objects, and combine it with LAT spectra for these sources to constrain these IGMF parameters. Low $B$ values can be ruled out by the constraint that the cascade flux cannot exceed that observed by the LAT. High values of $B$ can be ruled out from the constraint that the EBL-deabsorbed IACT spectrum cannot be greater than the LAT spectrum extrapolated into the VHE band, unless the cascade spectrum contributes a sizable fraction of the LAT flux. We rule out low $B$ values ($B< 10^{-19}$ G for $L_B\ge1$\ Mpc) at $>5\sigma$ in all trials with different EBL models and data selection, except when using $>1$ GeV spectra and the lowest EBL models. We were not able to constrain high values of $B$., Comment: 18 pages, 11 figures, 2 tables. Accepted by ApJ

Published
2015
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12. Design and characterization of a single photoelectron calibration system for the NectarCAM camera of the medium-sized telescopes of the Cherenkov Telescope Array

Author

Biasuzzi, Barbara, Pressard, Kevin, Biteau, Jonathan, Geoffroy, Brice, Goncalves, Carlos Domingues, Hull, Giulia, Imre, Miktat, Josselin, Michaël, Maroni, Alain, Mathon, Bernard, Seminor, Lucien, Suomijarvi, Tiina, Trung, Thi Nguyen, Vatrinet, Laurent, Brun, Patrick, Caroff, Sami, Fegan, Stephen, Ferreira, Oscar, Jean, Pierre, Karkar, Sonia, Olive, Jean-François, Rivoire, Stéphane, Sizun, Patrick, Thiant, Floris, Tsiahina, Adellain, Toussenel, François, and Vasileiadis, Georges

Published
2020
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13. TeV observations of SNRs and unidentified sources

Author

Fegan, Stephen

Subjects
Astrophysics
Abstract

A review of very high energy gamma-ray astronomy is presented. Particular attention is paid to the atmospheric Cherenkov imaging technique whose employment has resulted in detections of both galactic and extra-galactic objects at energies above 300GeV. Next generation ground-based telescopes promise to increase our knowledge of extreme astrophysical objects as they begin to operate over the next few years., Comment: 13 pages, 5 figures. To appear in the proceedings of The nature of unidentified galactic high-energy gamma-ray sources, Tonantzintla, Mexico, 2000

Published
2001

17. Incremental Fermi Large Area Telescope Fourth Source Catalog

Author

Abdollahi, Soheila, Acero, Fabio, Bloom, Elliott, Orienti, Monica, Orlando, Elena, Paneque, David, Pei, Zhiyuan, Perkins, Jeremy S., Persic, Massimo, Pesce-Rollins, Melissa, Petrosian, Vahe, Pillera, Roberta, Poon, Helen, Bonino, Raffaella, Porter, Troy A., Principe, Giacomo, Raino, Silvia, Rando, Riccardo, Rani, Bindu, Razzano, Massimiliano, Razzaque, Soebur, Reimer, Anita, Reimer, Olaf, Reposeur, Thierry, Brill, Ari, Sanchez-Conde, Miguel A., Saz Parkinson, Pablo M., Scotton, Lorenzo, Serini, Davide, Sgro, Carmelo, Siskind, Eric J., Smith, David A., Spandre, Gloria, Spinelli, Paolo, Sueoka, Kohei, Britto, Richard J., Suson, Dan J., Tajima, Hiro, Tak, Dongguen, Thayer, Jana B., Thompson, David J., Torres, Diego F., Troja, Eleonora, Valverde, Janeth, Wood, Kent, Zaharijas, Gabrijela, Bruel, Philippe, Fermi-LAT Collaboration, Burnett, Toby H., Buson, Sara, Cameron, Rob A., Caputo, Regina, Caraveo, Patrizia A., Baldini, Luca, Castro, Daniel, Chaty, Sylvain, Cheung, Teddy C., Chiaro, Graziano, Cibrario, Nicolo, Ciprini, Stefano, Coronado-Blazquez, Javier, Crnogorcevic, Milena, Cutini, Sara, D'Ammando, Filippo, Ballet, Jean, De Gaetano, Salvatore, Digel, Seth W., Di Lalla, Niccolo, Dirirsa, Feraol F., Di Venere, Leonardo, Dominguez, Alberto, Fallah Ramazani, Vandad, Fegan, Stephen J., Ferrara, Elizabeth C., Fiori, Alessio, Bastieri, Denis, Fleischhack, Henrike, Franckowiak, Anna, Fukazawa, Yasushi, Funk, Stefan, Fusco, Piergiorgio, Galanti, Giorgio, Gammaldi, Viviana, Gargano, Fabio, Garrappa, Simone, Gasparrini, Dario, Bellazzini, Ronaldo, Giacchino, Federica, Giglietto, Nico, Giordano, Francesco, Giroletti, Marcello, Glanzman, Thomas, Green, David, Grenier, Isabelle A., Grondin, Marie-Helene, Guillemot, Lucas, Guiriec, Sylvain, Berenji, Bijan, Gustafsson, Michael, Harding, Alice K., Hays, Liz, Hewitt, John W., Hays, E., Horan, Deirdre, Hou, Xian, Johannesson, Gudlaugur, Karwin, Christopher M., Kayanoki, Taishu, Berretta, Alessandra, Kerr, Matthew T., Kuss, Michael, Landriu, David, Larsson, Stefan, Latronico, Luca, Lemoine-Goumard, Marianne, Li, Jian, Liodakis, Ioannis, Longo, Francesco, Loparco, Francesco, Bissaldi, Elisabetta, Lott, Benoit, Lubrano, Pasquale, Maldera, Simone, Malyshev, Dmitry, Manfreda, Alberto, Marti-Devesa, Guillem, Mazziotta, Mario N., Mereu, Isabella, Meyer, Manuel, Michelson, Peter F., Blandford, Roger D., Mirabal, Nestor, Mitthumsiri, Warit, Mizuno, Tsunefumi, Moiseev, Alex A., Monzani, Maria E., Morselli, Aldo, Moskalenko, Igor V., Negro, Michela, Nuss, Eric, Omodei, Nicola, European Space Agency, National Science Foundation (US), National Aeronautics and Space Administration (US), Department of Energy (US), Agenzia Spaziale Italiana, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-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)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Unité Scientifique de la Station de Nançay (USN), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, and UAM. Departamento de Física Teórica

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Física, Astronomy and Astrophysics, Galaxies, Astronomi, astrofysik och kosmologi, Space and Planetary Science, BL Lacertae Object, Astronomy, Astrophysics and Cosmology, ddc:520, ddc:530, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Blazars
Abstract

Abdollahi et al., We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi Large Area Telescope (LAT) catalog of γ-ray sources. Based on the first 12 years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources., 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 is performed in part under DOE Contract DE-AC02-76SF00515. This work made extensive use of the ATNF pulsar catalog 102 (Manchester et al. 2005). This research has made use of the NASA/IPAC Extragalactic Database (NED; 2019), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, and of archival data, software, and online services provided by the ASI Science Data Center (ASDC) operated by the Italian Space Agency.

Published
2022
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18. Technical and scientific performance of the prototype Schwarzschild-Couder telescope for CTA

Author

Adams, Colin B., primary, Ambrosi, Giovanni, additional, Ambrosio, Michelangelo, additional, Aramo, Carla, additional, Batista, Pedro I., additional, Benbow, Wystan, additional, Bertucci, Bruna, additional, Bissaldi, Elisabetta, additional, Bitossi, Massimiliano, additional, Boiano, Alfonso, additional, Bonavolontà, Carmela, additional, Bose, Richard G., additional, Brill, Aryeh L., additional, Brown, Anthony M., additional, Buckley, James H., additional, Canestrari, Rodolfo, additional, Capasso, Massimo, additional, Caprai, Mirco, additional, Covault, Corbin E., additional, Depaoli, Davide, additional, Di Venere, Leonardo, additional, Errando, Manel, additional, Fegan, Stephen, additional, Feng, Qi, additional, Fiandrini, Emanuale, additional, Furniss, Amy, additional, Gent, Alasdair, additional, Giglietto, Nicola, additional, Giordano, Francesco, additional, Giro, Enrico, additional, Halliday, Robert, additional, Hervet, Olivier, additional, Holder, Jamie, additional, Humensky, Thomas B., additional, Incardona, Simone, additional, Ionica, Maria, additional, Jin, Weidong, additional, Kieda, David B., additional, Licciulli, Francesco, additional, Loporchio, Serena, additional, Marsella, Giovanni, additional, Masone, Vincenzo, additional, Meagher, Kevin, additional, Meures, Thomas, additional, Mode, Brent A., additional, Mognet, Samuel A., additional, Mukherjee, Reshmi, additional, Nieto, Daniel, additional, Okumura, Akira, additional, Otte, Nepomuk, additional, Pantaleo, Francesca R., additional, Paoletti, Riccardo, additional, Pareschi, Giovanni, additional, Di Pierro, Federico, additional, Pueschel, Elisa, additional, Ribeiro, Deivid, additional, Riitano, Luca, additional, Roache, Emmet, additional, Ross, Duncan, additional, Rousselle, Julien, additional, Rugliancich, Andrea, additional, Santander, Marcos, additional, Shang, Ruo-Yu, additional, Stiaccini, Leonardo, additional, Tajima, Hiroyasu, additional, Taylor, Leslie P., additional, Tosti, Luca, additional, Tovmassian, Gagik, additional, Tripodo, Giovanni, additional, Vagelli, Valerio, additional, Valentino, Massimo, additional, Vanderbrouke, Justin, additional, Vassiliev, Vladimir V., additional, Watson, Jason J., additional, White, Richard, additional, Williams, David A., additional, Yu, Peter, additional, and Zink, Adrian, additional

Published
2021
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19. Verification of the optical system of the 9.7-m prototype Schwarzschild-Couder Telescope

Author

Adams, Colin, primary, Alfaro, Ruben, additional, Ambrosi, Giovanni, additional, Ambrosio, Michelangelo, additional, Aramo, Carla, additional, Benbow, Wystan, additional, Bertucci, Bruna, additional, Bissaldi, Elisabetta, additional, Bitossi, M., additional, Boiano, Alfonso, additional, Bonavolontà, Carmela, additional, Bose, Richard, additional, Brill, A., additional, Buckley, James H., additional, Byrum, Karen, additional, Cameron, Robert A., additional, Capasso, Massimo, additional, Caprai, Mirco, additional, Covault, Corbin E., additional, Di Venere, Leonardo, additional, Fegan, Stephen, additional, Feng, Qi, additional, Fiandrini, Emanuele, additional, Furniss, Amy, additional, Garczarczyk, Markus, additional, Garfias, Fernando, additional, Gent, Alasdair, additional, Giglietto, Nicola, additional, Giordano, Francesco, additional, González, Magdalena M., additional, Halliday, Rob, additional, Hervet, Olivier, additional, Hughes, Gareth, additional, Humensky, Thomas B., additional, Ionica, Maria, additional, Iriarte, Arturo, additional, Jin, Weidong, additional, Kaarat, Philip, additional, Kieda, David B., additional, Kim, Bryan, additional, Licciulli, Francesco, additional, Limon, Michele, additional, Loporchio, Serena, additional, Masone, Vincenzo, additional, Meures, Thomas, additional, Mode, Brent A., additional, Mukherjee, Reshmi, additional, Nieto, Daniel, additional, Okumura, Akira, additional, Otte, A. Nepomuk, additional, La Palombara, Nicola, additional, Pantaleo, Francesca R., additional, Paoletti, Ricardo, additional, Pareschi, Giovanni, additional, Petrashyk, Andriy, additional, Powell, Jake, additional, Powell, Katherine, additional, Ribeiro, Deivid, additional, Roache, Emmet, additional, Rousselle, Julien, additional, Rugliancich, Andrea, additional, Ruiz, Jaime, additional, Santander, Marcos, additional, Schlenstedt, Stefan, additional, Scuderi, Salvatore, additional, Shang, Ruo-Yu, additional, Sironi, Giorgia, additional, Stevenson, Brandon, additional, Stiaccini, Leonardo, additional, Taylor, Leslie P., additional, Tosti, Luca, additional, Tovmassian, Gagik, additional, Vagelli, Valerio, additional, Valentino, M., additional, Vandenbroucke, Justin, additional, Vassiliev, Vladimir V., additional, Wakely, Scott P., additional, Wilcox, Patrick, additional, Williams, David A., additional, and Yu, Peter, additional

Published
2020
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25. A very high energy gamma-ray survey of unidentified EGRET sources

Author

Fegan, Stephen and Fegan, Stephen

Abstract

A survey of unidentified 100 MeV γ-ray sources is undertaken, with the Whipple 10m telescope, with the objective of detecting very high energy (>350 GeV) γ-ray emission. The survey consists of nineteen sets of observations of sources detected by the EGRET instrument on the Compton Gamma-Ray Observatory between 1991 and 1995. Results for 21 EGRET sources are reported; in some cases two EGRET sources are close enough to be viewed in a single observation. For each EGRET source, candidate associations are listed and the implications of each candidate for VHE emission discussed. Finally, a study of the performance of a next-generation ground based instrument, VERITAS, using simulations is presented. The implications of the increased sensitivity of such an instrument for suture gamma-ray surveys is briefly discussed.

Published
2004

26. A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase

Author

Valverde, Janeth, Horan, Deirdre, Bernard, Denis, Fegan, Stephen, Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brill, A., Brose, R., Buchovecky, M., Buckley, J. H., Christiansen, J. L., Cui, W., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Gent, A., Gillanders, G. H., Giuri, C., Gueta, O., Hanna, D., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kelley-Hoskins, Nathan, Kertzman, M., Kieda, D., Krause, Maria, Krennrich, F., Lang, M. J., Maier, G., Moriarty, P., Mukherjee, R., Nieto, D., Nievas-Rosillo, M., O’Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pfrang, K., Pichel, A., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Richards, G. T., Roache, E., Sadeh, I., Santander, M., Scott, S. S., Sembroski, G. H., Shahinyan, K., Shang, R., Sushch, I., Vassiliev, V. V., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J, Noto, Giuliana, Edwards, P. G., Piner, B. G., Ramazani, V. Fallah, Hovatta, T., Jormanainen, J., Lindfors, E., Nilsson, K., Takalo, L., Kovalev, Y. Y., Lister, M. L., Pushkarev, A. B., Savolainen, T., Kiehlmann, S., Max-Moerbeck, W., Readhead, A. C. S., Lähteenmäki, A., and Tornikoski, M.

Subjects
4/3, 7. Clean energy, GLAST, blazar, flux, X-ray, gamma ray: emission, 13. Climate action, correlation, synchrotron, infrared, VERITAS, polarization: optical
Abstract

The astrophysical journal / 1 Part 1 891(2), 170 - (2020). doi:10.3847/1538-4357/ab765d, Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and VERITAS, we present an extensive study of the long-term multi-wavelength radio-to-gamma-ray flux-density variability, with the addition of a couple of short-time radio-structure and optical polarization observations of the blazar 1ES 1215+303 (z=0.130), with a focus on its gamma-ray emission from 100 MeV to 30 TeV. Multiple strong GeV gamma-ray flares, a long-term increase in the gamma-ray and optical flux baseline and a linear correlation between these two bands are observed over the ten-year period. Typical HBL behaviors are identified in the radio morphology and broadband spectrum of the source. Three stationary features in the innermost jet are resolved by VLBA at 43.1, 22.2, and 15.3 GHz. We employ a two-component synchrotron self-Compton model to describe different flux states of the source, including the epoch during which an extreme shift in energy of the synchrotron peak frequency from infrared to soft X-rays is observed., Published by Institute of Physics Publ., London

27. Priest 'kissed girl, 15'.

Author

Catherine Fegan; Stephen Maguire

Abstract

A PRIEST has temporarily stepped down over allegations that he kissed a 15-year-old girl. [ABSTRACT FROM PUBLISHER]

Published
2010

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