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14 results on '"G. Principe"'

1. Periodic Gamma-Ray Modulation of the Blazar PG 1553+113 Confirmed by Fermi-LAT and Multiwavelength Observations

Author

S. Abdollahi, L. Baldini, G. Barbiellini, R. Bellazzini, B. Berenji, E. Bissaldi, R. D. Blandford, R. Bonino, P. Bruel, S. Buson, R. A. Cameron, P. A. Caraveo, F. Casaburo, E. Cavazzuti, C. C. Cheung, G. Chiaro, S. Ciprini, G. Cozzolongo, P. Cristarella Orestano, S. Cutini, F. D’Ammando, N. Di Lalla, F. Dirirsa, L. Di Venere, A. Domínguez, S. J. Fegan, E. C. Ferrara, A. Fiori, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Garrappa, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, E. Hays, D. Horan, M. Kuss, S. Larsson, M. Laurenti, J. Li, I. Liodakis, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, D. Malyshev, A. Manfreda, L. Marcotulli, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, P. F. Michelson, W. Mitthumsiri, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, M. Perri, M. Persic, M. Pesce-Rollins, T. A. Porter, G. Principe, S. Rainò, R. Rando, B. Rani, M. Razzano, A. Reimer, O. Reimer, P. M. Saz Parkinson, L. Scotton, D. Serini, A. Sesana, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, M. N. Takahashi, D. Tak, J. B. Thayer, D. J. Thompson, D. F. Torres, J. Valverde, F. Verrecchia, and G. Zaharijas

Subjects
Active galactic nuclei, Blazars, Gamma-rays, Gamma-ray sources, Gamma-ray telescopes, Gamma-ray astronomy, Astrophysics, QB460-466
Abstract

A 2.1 yr periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in ∼7 yr of data from the Fermi Large Area Telescope. After 15 yr of Fermi sky-survey observations, doubling the total time range, we report >7 cycle gamma-ray modulation with an estimated significance of 4 σ against stochastic red noise. Independent determinations of oscillation period and phase in the earlier and the new data are in close agreement (chance probability

Published
2024
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2. Fermi-GBM Discovery of GRB 221009A: An Extraordinarily Bright GRB from Onset to Afterglow

Author

S. Lesage, P. Veres, M. S. Briggs, A. Goldstein, D. Kocevski, E. Burns, C. A. Wilson-Hodge, P. N. Bhat, D. Huppenkothen, C. L. Fryer, R. Hamburg, J. Racusin, E. Bissaldi, W. H. Cleveland, S. Dalessi, C. Fletcher, M. M. Giles, B. A. Hristov, C. M. Hui, B. Mailyan, C. Malacaria, S. Poolakkil, O. J. Roberts, A. von Kienlin, J. Wood, M. Ajello, M. Arimoto, L. Baldini, J. Ballet, M. G. Baring, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, R. D. Blandford, R. Bonino, P. Bruel, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, G. Chiaro, N. Cibrario, S. Ciprini, P. Cristarella Orestano, M. Crnogorcevic, A. Cuoco, S. Cutini, F. D’Ammando, S. De Gaetano, N. Di Lalla, L. Di Venere, A. Domínguez, S. J. Fegan, E. C. Ferrara, H. Fleischhack, Y. Fukazawa, S. Funk, P. Fusco, G. Galanti, V. Gammaldi, F. Gargano, C. Gasbarra, D. Gasparrini, S. Germani, F. Giacchino, N. Giglietto, R. Gill, M. Giroletti, J. Granot, D. Green, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, J. W. Hewitt, D. Horan, X. Hou, M. Kuss, L. Latronico, A. Laviron, M. Lemoine-Goumard, J. Li, I. Liodakis, F. Longo, F. Loparco, L. Lorusso, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, J. E. McEnery, I. Mereu, M. Meyer, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, G. Panzarini, M. Persic, M. Pesce-Rollins, R. Pillera, F. Piron, H. Poon, T. A. Porter, G. Principe, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, F. Ryde, M. Sánchez-Conde, P. M. Saz Parkinson, L. Scotton, D. Serini, C. Sgrò, V. Sharma, E. J. Siskind, G. Spandre, P. Spinelli, H. Tajima, D. F. Torres, J. Valverde, T. Venters, Z. Wadiasingh, K. Wood, and G. Zaharijas

Subjects
Gamma-ray bursts, Astrophysics, QB460-466
Abstract

We report the discovery of GRB 221009A, the highest flux gamma-ray burst (GRB) ever observed by the Fermi Gamma-ray Burst Monitor (Fermi-GBM). This GRB has continuous prompt emission lasting more than 600 s, which smoothly transitions to afterglow emission visible in the Fermi-GBM energy range (8 keV–40 MeV), and total energetics higher than any other burst in the Fermi-GBM sample. By using a variety of new and existing analysis techniques we probe the spectral and temporal evolution of GRB 221009A. We find no emission prior to the Fermi-GBM trigger time ( t _0 ; 2022 October 9 at 13:16:59.99 UTC), indicating that this is the time of prompt emission onset. The triggering pulse exhibits distinct spectral and temporal properties suggestive of the thermal, photospheric emission of shock breakout, with significant emission up to ∼15 MeV. We characterize the onset of external shock at t _0 + 600 s and find evidence of a plateau region in the early-afterglow phase, which transitions to a slope consistent with Swift-XRT afterglow measurements. We place the total energetics of GRB 221009A in context with the rest of the Fermi-GBM sample and find that this GRB has the highest total isotropic-equivalent energy ( E _γ _,iso = 1.0 × 10 ^55 erg) and second highest isotropic-equivalent luminosity ( L _γ _,iso = 9.9 × 10 ^53 erg s ^–1 ) based on its redshift of z = 0.151. These extreme energetics are what allowed us to observe the continuously emitting central engine of Fermi-GBM from the beginning of the prompt emission phase through the onset of early afterglow.

Published
2023
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3. The Fermi-LAT Lightcurve Repository

Author

S. Abdollahi, M. Ajello, L. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. Bonino, A. Brill, P. Bruel, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, N. Cibrario, S. Ciprini, P. Cristarella Orestano, M. Crnogorcevic, S. Cutini, F. D’Ammando, S. De Gaetano, S. W. Digel, N. Di Lalla, L. Di Venere, A. Domínguez, V. Fallah Ramazani, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, A. Franckowiak, Y. Fukazawa, P. Fusco, V. Gammaldi, F. Gargano, S. Garrappa, C. Gasbarra, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, D. Horan, X. Hou, G. Jóhannesson, M. Kerr, D. Kocevski, M. Kuss, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, L. Lorusso, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, M. Meyer, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, G. Panzarini, J. S. Perkins, M. Persic, M. Pesce-Rollins, R. Pillera, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, M. Sánchez-Conde, P. M. Saz Parkinson, Jeff Scargle, L. Scotton, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, D. J. Thompson, D. F. Torres, J. Valverde, T. Venters, Z. Wadiasingh, S. Wagner, and K. Wood

Subjects
Gamma-ray astronomy, Active galactic nuclei, Light curves, Astrophysics, QB460-466
Abstract

The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal.

Published
2023
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4. Multimessenger Characterization of Markarian 501 during Historically Low X-Ray and γ-Ray Activity

Author

H. Abe, S. Abe, V. A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, I. Burelli, G. Busetto, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, G. Ceribella, Y. Chai, A. Chilingarian, S. Cikota, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, V. Fallah Ramazani, L. Fariña, A. Fattorini, L. Foffano, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau, D. Green, J. G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, E. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, H. A. Mondal, A. Moralejo, D. Morcuende, V. Moreno, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, T. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P. G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J. L. Schubert, T. Schweizer, J. Sitarek, V. Sliusar, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C. F. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, The MAGIC Collaboration, M. Cerruti, J. A. Acosta-Pulido, G. Apolonio, R. Bachev, M. Baloković, E. Benítez, I. Björklund, V. Bozhilov, L. F. Brown, A. Bugg, W. Carbonell, M. I. Carnerero, D. Carosati, C. Casadio, W. Chamani, W. P. Chen, R. A. Chigladze, G. Damljanovic, K. Epps, A. Erkenov, M. Feige, J. Finke, A. Fuentes, K. Gazeas, M. Giroletti, T. S. Grishina, A. C. Gupta, M. A. Gurwell,, E. Heidemann, D. Hiriart, W. J. Hou, T. Hovatta, S. Ibryamov, M. D. Joner, S. G. Jorstad, J. Kania, S. Kiehlmann, G. N. Kimeridze, E. N. Kopatskaya, M. Kopp, M. Korte, B. Kotas, S. Koyama, J. A. Kramer, L. Kunkel, S. O. Kurtanidze, O. M. Kurtanidze, A. Lähteenmäki, J. M. López, V. M. Larionov, E. G. Larionova, L. V. Larionova, C. Leto, C. Lorey, R. Mújica, G. M. Madejski, N. Marchili, A. P. Marscher, M. Minev, A. Modaressi, D. A. Morozova, T. Mufakharov, I. Myserlis, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, M. Perri, C. M. Raiteri, A. C. S. Readhead, A. Reimer, D. Reinhart, S. Righini, K. Rosenlehner, A. C. Sadun, S. S. Savchenko, A. Scherbantin, L. Schneider, K. Schoch, D. Seifert, E. Semkov, L. A. Sigua, C. Singh, P. Sola, Y. Sotnikova, M. Spencer, R. Steineke, M. Stojanovic, A. Strigachev, M. Tornikoski, E. Traianou, A. Tramacere, Yu. V. Troitskaya, I. S. Troitskiy, J. B. Trump, A. Tsai, A. Valcheva, A. A. Vasilyev, F. Verrecchia, M. Villata, O. Vince, K. Vrontaki, Z. R. Weaver, E. Zaharieva, and N. Zottmann

Subjects
Active galaxies, BL Lacertae objects, Markarian galaxies, Active galactic nuclei, Blazars, Astrophysics, QB460-466
Abstract

We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) γ -rays. A significant correlation (>3 σ ) between X-rays and VHE γ -rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ -rays and radio, with the radio lagging by more than 100 days, placing the γ -ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE γ -rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.

Published
2023
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5. Observations of the Crab Nebula and Pulsar with the Large-sized Telescope Prototype of the Cherenkov Telescope Array

Author

H. Abe, K. Abe, S. Abe, A. Aguasca-Cabot, I. Agudo, N. Alvarez Crespo, L. A. Antonelli, C. Aramo, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, P. Aubert, A. Baktash, A. Bamba, A. Baquero Larriva, L. Baroncelli, U. Barres de Almeida, J. A. Barrio, I. Batkovic, J. Baxter, J. Becerra González, E. Bernardini, M. I. Bernardos, J. Bernete Medrano, A. Berti, P. Bhattacharjee, N. Biederbeck, C. Bigongiari, E. Bissaldi, O. Blanch, G. Bonnoli, P. Bordas, A. Borghese, A. Bulgarelli, I. Burelli, M. Buscemi, M. Cardillo, S. Caroff, A. Carosi, F. Cassol, D. Cauz, G. Ceribella, Y. Chai, K. Cheng, A. Chiavassa, M. Chikawa, L. Chytka, A. Cifuentes, J. L. Contreras, J. Cortina, H. Costantini, G. D’Amico, M. Dalchenko, A. De Angelis, M. de Bony de Lavergne, B. De Lotto, R. de Menezes, G. Deleglise, C. Delgado, J. Delgado Mengual, D. della Volpe, M. Dellaiera, D. Depaoli, A. Di Piano, F. Di Pierro, R. Di Tria, L. Di Venere, C. Díaz, R. M. Dominik, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsässer, G. Emery, J. Escudero, V. Fallah Ramazani, G. Ferrara, F. Ferrarotto, A. Fiasson, L. Freixas Coromina, S. Fröse, S. Fukami, Y. Fukazawa, E. Garcia, R. Garcia López, C. Gasbarra, D. Gasparrini, F. Geyer, J. Giesbrecht Paiva, N. Giglietto, F. Giordano, E. Giro, P. Gliwny, N. Godinovic, R. Grau, D. Green, J. Green, S. Gunji, J. Hackfeld, D. Hadasch, A. Hahn, K. Hashiyama, T. Hassan, K. Hayashi, L. Heckmann, M. Heller, J. Herrera Llorente, K. Hirotani, D. Hoffmann, D. Horns, J. Houles, M. Hrabovsky, D. Hrupec, D. Hui, M. Hütten, M. Iarlori, R. Imazawa, T. Inada, Y. Inome, K. Ioka, M. Iori, K. Ishio, Y. Iwamura, M. Jacquemont, I. Jimenez Martinez, J. Jurysek, M. Kagaya, V. Karas, H. Katagiri, J. Kataoka, D. Kerszberg, Y. Kobayashi, A. Kong, H. Kubo, J. Kushida, M. Lainez, G. Lamanna, A. Lamastra, T. Le Flour, M. Linhoff, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, P. L. Luque-Escamilla, P. Majumdar, M. Makariev, D. Mandat, M. Manganaro, G. Manicò, K. Mannheim, M. Mariotti, P. Marquez, G. Marsella, J. Martí, O. Martinez, G. Martínez, M. Martínez, P. Marusevec, A. Mas-Aguilar, G. Maurin, D. Mazin, E. Mestre Guillen, S. Micanovic, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, T. Mizuno, M. Molero Gonzalez, E. Molina, T. Montaruli, I. Monteiro, A. Moralejo, D. Morcuende, A. Morselli, K. Mrakovcic, K. Murase, A. Nagai, S. Nagataki, T. Nakamori, L. Nickel, M. Nievas, K. Nishijima, K. Noda, D. Nosek, S. Nozaki, M. Ohishi, Y. Ohtani, T. Oka, N. Okazaki, A. Okumura, R. Orito, J. Otero-Santos, M. Palatiello, D. Paneque, F. R. Pantaleo, R. Paoletti, J. M. Paredes, M. Pech, M. Pecimotika, M. Peresano, A. Pérez, E. Pietropaolo, G. Pirola, C. Plard, F. Podobnik, V. Poireau, M. Polo, E. Pons, E. Prandini, J. Prast, G. Principe, C. Priyadarshi, M. Prouza, R. Rando, W. Rhode, M. Ribó, V. Rizi, G. Rodriguez Fernandez, J. E. Ruiz, T. Saito, S. Sakurai, D. A. Sanchez, T. Šarić, Y. Sato, F. G. Saturni, B. Schleicher, F. Schmuckermaier, J. L. Schubert, F. Schussler, T. Schweizer, M. Seglar Arroyo, R. Silvia, J. Sitarek, V. Sliusar, A. Spolon, J. Strišković, M. Strzys, Y. Suda, Y. Sunada, H. Tajima, H. Takahashi, M. Takahashi, J. Takata, R. Takeishi, P. H. T. Tam, S. J. Tanaka, D. Tateishi, L. A. Tejedor, P. Temnikov, Y. Terada, K. Terauchi, T. Terzic, M. Teshima, M. Tluczykont, F. Tokanai, D. F. Torres, P. Travnicek, S. Truzzi, A. Tutone, G. Uhlrich, M. Vacula, P. Vallania, J. van Scherpenberg, M. Vázquez Acosta, V. Verguilov, I. Viale, A. Vigliano, C. F. Vigorito, V. Vitale, G. Voutsinas, I. Vovk, T. Vuillaume, R. Walter, M. Will, T. Yamamoto, R. Yamazaki, T. Yoshida, T. Yoshikoshi, N. Zywucka, K. Bernlöhr, O. Gueta, K. Kosack, G. Maier, and J. Watson

Subjects
Gamma-ray astronomy, Gamma-ray sources, Astronomy data analysis, Pulsar wind nebulae, Pulsars, Astrophysics, QB460-466
Abstract

The Cherenkov Telescope Array (CTA) is a next-generation ground-based observatory for gamma-ray astronomy at very high energies. The Large-Sized Telescope prototype (LST-1) is located at the CTA-North site, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to ≃20 GeV. LST-1 started performing astronomical observations in 2019 November, during its commissioning phase, and it has been taking data ever since. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high-energy gamma-ray astronomy, and use them, together with simulations, to assess the performance of the telescope. LST-1 has reached the expected performance during its commissioning period—only a minor adjustment of the preexisting simulations was needed to match the telescope’s behavior. The energy threshold at trigger level is around 20 GeV, rising to ≃30 GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.°12–0.°40, and energy resolution from 15%–50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50 hr observation (12% for 30 minutes). The spectral energy distribution (in the 0.03–30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula.

Published
2023
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6. The Third Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars

Author

D. A. Smith, S. Abdollahi, M. Ajello, M. Bailes, L. Baldini, J. Ballet, M. G. Baring, C. Bassa, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, B. Bhattacharyya, E. Bissaldi, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, M. Burgay, T. H. Burnett, R. A. Cameron, F. Camilo, R. Caputo, P. A. Caraveo, E. Cavazzuti, G. Chiaro, S. Ciprini, C. J. Clark, I. Cognard, A. Corongiu, P. Cristarella Orestano, M. Crnogorcevic, A. Cuoco, S. Cutini, F. D’Ammando, A. de Angelis, M. E. DeCesar, S. De Gaetano, R. de Menezes, J. Deneva, F. de Palma, N. Di Lalla, F. Dirirsa, L. Di Venere, A. Domínguez, D. Dumora, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, C. Flynn, A. Franckowiak, P. C. C. Freire, Y. Fukazawa, P. Fusco, G. Galanti, V. Gammaldi, F. Gargano, D. Gasparrini, F. Giacchino, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, L. Guillemot, S. Guiriec, M. Gustafsson, A. K. Harding, E. Hays, J. W. Hewitt, D. Horan, X. Hou, F. Jankowski, R. P. Johnson, T. J. Johnson, S. Johnston, J. Kataoka, M. J. Keith, M. Kerr, M. Kramer, M. Kuss, L. Latronico, S.-H. Lee, D. Li, J. Li, B. Limyansky, F. Longo, F. Loparco, L. Lorusso, M. N. Lovellette, M. Lower, P. Lubrano, A. G. Lyne, Y. Maan, S. Maldera, R. N. Manchester, A. Manfreda, M. Marelli, G. Martí-Devesa, M. N. Mazziotta, J. E. McEnery, I. Mereu, P. F. Michelson, M. Mickaliger, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, M. Negro, R. Nemmen, L. Nieder, E. Nuss, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, M. Palatiello, D. Paneque, G. Panzarini, A. Parthasarathy, M. Persic, M. Pesce-Rollins, R. Pillera, H. Poon, T. A. Porter, A. Possenti, G. Principe, S. Rainò, R. Rando, S. M. Ransom, P. S. Ray, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, N. Renault-Tinacci, R. W. Romani, M. Sánchez-Conde, P. M. Saz Parkinson, L. Scotton, D. Serini, C. Sgrò, R. Shannon, V. Sharma, Z. Shen, E. J. Siskind, G. Spandre, P. Spinelli, B. W. Stappers, T. E. Stephens, D. J. Suson, S. Tabassum, H. Tajima, D. Tak, G. Theureau, D. J. Thompson, O. Tibolla, D. F. Torres, J. Valverde, C. Venter, Z. Wadiasingh, N. Wang, P. Wang, P. Weltevrede, K. Wood, J. Yan, G. Zaharijas, C. Zhang, and W. Zhu

Subjects
Binary pulsars, Millisecond pulsars, Pulsar timing method, Rotation powered pulsars, Pulsars, Gamma-rays, Astrophysics, QB460-466
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 colocated 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 ≤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 six undetected in radio. Overall, ≥236 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.

Published
2023
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7. The Fermi-LAT Light Curve Repository

Author

S. Abdollahi, M. Ajello, L. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. Bonino, A. Brill, P. Bruel, E. Burns, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, N. Cibrario, S. Ciprini, P. Cristarella Orestano, M. Crnogorcevic, S. Cutini, F. D’Ammando, S. De Gaetano, S. W. Digel, N. Di Lalla, L. Di Venere, A. Domínguez, V. Fallah Ramazani, S. J. Fegan, E. C. Ferrara, A. Fiori, H. Fleischhack, A. Franckowiak, Y. Fukazawa, P. Fusco, V. Gammaldi, F. Gargano, S. Garrappa, C. Gasbarra, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, S. Guiriec, M. Gustafsson, E. Hays, D. Horan, X. Hou, G. Jóhannesson, M. Kerr, D. Kocevski, M. Kuss, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, L. Lorusso, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, G. Martí-Devesa, M. N. Mazziotta, I. Mereu, M. Meyer, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, G. Panzarini, J. S. Perkins, M. Persic, M. Pesce-Rollins, R. Pillera, T. A. Porter, G. Principe, J. L. Racusin, S. Rainò, R. Rando, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, M. Sánchez-Conde, P. M. Saz Parkinson, Jeff Scargle, L. Scotton, D. Serini, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, D. J. Suson, H. Tajima, D. J. Thompson, D. F. Torres, J. Valverde, T. Venters, Z. Wadiasingh, S. Wagner, K. Wood, and UAM. Departamento de Física Teórica

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Active galactic nuclei, Light Curves (918), Gamma-ray astronomy, Space and Planetary Science, Física, FOS: Physical sciences, Gamma-ray astronomy, Active galactic nuclei, Light curves, Astrophysics - High Energy Astrophysical Phenomena, Gamma-Ray Astronomy (628), Astronomy and Astrophysics, Active Galactic Nuclei (16), Light curves, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiere, The Fermi Large Area Telescope (LAT) lightcurve repository (LCR) is a publicly available, continually updated library of gamma-ray lightcurves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality lightcurves binned on timescales of 3, 7, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 yr of Fermi-LAT observations. The repository consists of lightcurves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multimessenger communities by allowing users to search LAT data quickly to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal, M.N. and J.V. acknowledge that the material is based upon work supported by NASA under award number 80GSFC21M0002. D.K. and M.N. acknowledge support to this work from NASA Fermi GI Program under grant number 80NSSC23K0242. A.B. is supported by the NASA Postdoctoral Program at NASA Goddard Space Flight Center, administered by Oak Ridge Associated Universities. INFN and ASI personnel performed in part under ASI-INFN Agreements No. 2021-43-HH.0. Work at NRL is supported by NASA. 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

Published
2023
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11. In vitro and in vivo evidence of the antineoplastic activity of quercetin against endothelial cells transformed by Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor.

Author

Principe G, Lezcano V, Tiburzi S, Miravalles AB, García BN, Gumilar F, and González-Pardo V

Subjects
Animals, Humans, Mice, Receptors, G-Protein-Coupled metabolism, Apoptosis drug effects, Antineoplastic Agents pharmacology, Cell Proliferation drug effects, Xenograft Model Antitumor Assays, Receptors, Chemokine, Quercetin pharmacology, Sarcoma, Kaposi drug therapy, Sarcoma, Kaposi pathology, Sarcoma, Kaposi virology, Sarcoma, Kaposi metabolism, Herpesvirus 8, Human drug effects, Mice, Nude, Endothelial Cells drug effects, Endothelial Cells metabolism
Abstract

Quercetin (QUE) is a natural flavonoid with well-known anticancer capabilities, although its effect on viral-induced cancers is less studied. Kaposi's sarcoma (KS) is a viral cancer caused by the human herpesvirus-8, which, during its lytic phase, expresses a constitutively activated viral G protein-coupled receptor (vGPCR) able to induce oncogenic modifications that lead to tumor development. The aim of this work was to investigate the potential effect of QUE on in vitro and in vivo models of Kaposi's sarcoma, developed by transforming endothelial cells with the vGPCR of Kaposi's sarcoma-associated herpesvirus. Initially, the antiproliferative effect of QUE was determined in endothelial cells stably expressing the vGPCR (vGPCR cells), with an IC50 of 30 μM. Additionally, QUE provoked a decrease in vGPCR cell viability, interfered with the cell cycle progression, and induced apoptosis, as revealed by annexin V/PI analysis and caspase-3 activity. The presence of apoptotic bodies and disorganized actin filaments was observed by SEM and phalloidin staining. Furthermore, tumors from vGPCR cells were induced in nude mice, which were treated with QUE (50 or 100 mg/kg/d) resulting in retarded tumor progression and reduced tumor weight. Notably, neither kidney nor liver damage was observed, as indicated by biochemical parameters in serum. In conclusion, this study suggests for the first time that QUE exhibits antineoplastic activity in both in vitro and in vivo models of KS, marking a starting point for further investigations and protocols for therapeutic purpose., (Copyright © 2024 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Published
2025
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12. 1α,25(OH) 2 D 3 regulates pro-angiogenic factors in endothelial cells transformed by Kaposi's sarcoma-associated herpesvirus G protein coupled receptor.

Author

Tapia C, Principe G, and González-Pardo V

Subjects
Mice, Animals, Angiogenesis Inducing Agents metabolism, Vascular Endothelial Growth Factor A genetics, Transcription Factor AP-1 metabolism, Receptors, G-Protein-Coupled genetics, Receptors, G-Protein-Coupled metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Hypoxia metabolism, Endothelial Cells metabolism, Herpesvirus 8, Human genetics, Herpesvirus 8, Human metabolism
Abstract

When tumoral cell expansion exceeds the vascular supply, regions of hypoxia or low oxygen concentration are generated promoting the formation of new vessels through cell proliferation and migration. Viral G protein-coupled receptor (vGPCR) is associated to Kaposi's sarcoma pathology and induces a paracrine transformation when is stably expressed in murine endothelial cells activating hypoxia-induced transcription factors. Previously, we reported the antiproliferative actions of 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3 ) in endothelial cells transformed by the vGPCR (SVEC-vGPCR). Herein, we further investigated if pro-angiogenic factors as AP-1, HIF-1α and VEGF are modulated by 1α,25(OH) 2 D 3 . We found by qRT-PCR analysis that the mRNA level of JunB, a negative regulator of cell proliferation, was similarly increased at all-time points tested after 1α,25(OH) 2 D 3 treatment in SVEC-vGPCR cells. Also, mRNA levels of the pro-angiogenic factor c-Fos, which induces tumor invasion, were only decreased during one short period treatment. In addition, Hif-1α mRNA and protein levels were significantly reduced after 1α,25(OH) 2 D 3 treatment in a VDR dependent fashion. However, mRNA levels of the angiogenic activator Vegf, promoted in turn by Hif-1α expression, were surprisingly high depending on VDR expression as well. Moreover, Egr-1, which has been reported to induce VEGF expression independently of HIF-1α, diminished its expression with 1α,25(OH) 2 D 3 treatment, fact that was related to the decline of p-ERK1/2. Altogether, these results suggest a negative modulation of some pro-angiogenic factors like AP-1 and HIF-1α, as part of the antiproliferative mechanism of 1α,25(OH) 2 D 3 in SVEC-vGPCR endothelial cells., Competing Interests: Declaration of competing interest All authors declare there are no conflicts of interest., (Copyright © 2023 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Published
2023
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13. Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC.

Author

Abe H, Abe S, Acciari VA, Aniello T, Ansoldi S, Antonelli LA, Arbet Engels A, Arcaro C, Artero M, Asano K, Baack D, Babić A, Baquero A, Barres de Almeida U, Barrio JA, Batković I, Baxter J, Becerra González J, Bednarek W, Bernardini E, Bernardos M, Berti A, Besenrieder J, Bhattacharyya W, Bigongiari C, Biland A, Blanch O, Bonnoli G, Bošnjak Ž, Burelli I, Busetto G, Carosi R, Carretero-Castrillo M, Ceribella G, Chai Y, Chilingarian A, Cikota S, Colombo E, Contreras JL, 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, Do Souto Espiñeira E, Dominis Prester D, Donini A, Dorner D, Doro M, Elsaesser D, Emery G, Fallah Ramazani V, Fariña L, Fattorini A, Font L, Fruck C, Fukami S, Fukazawa Y, García López RJ, Garczarczyk M, Gasparyan S, Gaug M, Giesbrecht Paiva JG, Giglietto N, Giordano F, Gliwny P, Godinović N, Green JG, Green D, Hadasch D, Hahn A, Hassan T, Heckmann L, Herrera J, Hrupec D, Hütten M, Imazawa R, Inada T, Iotov R, Ishio K, Jiménez Martínez I, Jormanainen J, Kerszberg D, Kobayashi Y, Kubo H, Kushida J, Lamastra A, Lelas D, Leone F, Lindfors E, Linhoff L, Lombardi S, Longo F, López-Coto R, López-Moya M, López-Oramas A, Loporchio S, Lorini A, Lyard E, 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, Miener T, Miranda JM, Mirzoyan R, Molina E, Mondal HA, Moralejo A, Morcuende D, Moreno V, Nakamori T, Nanci C, Nava L, Neustroev V, Nievas Rosillo M, Nigro C, Nilsson K, Nishijima K, Njoh Ekoume T, Noda K, Nozaki S, Ohtani Y, Oka T, Otero-Santos J, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes JM, Pavletić L, Persic M, Pihet M, Podobnik F, Prada Moroni PG, Prandini E, Principe G, Priyadarshi C, Puljak I, Rhode W, Ribó M, Rico J, Righi C, Rugliancich A, Sahakyan N, Saito T, Sakurai S, Satalecka K, Saturni FG, Schleicher B, Schmidt K, Schmuckermaier F, Schubert JL, Schweizer T, Sitarek J, Sliusar V, Sobczynska D, Spolon A, Stamerra A, Strišković J, Strom D, Strzys M, Suda Y, Surić T, Takahashi M, Takeishi R, Tavecchio F, Temnikov P, Terauchi K, Terzić T, Teshima M, Tosti L, Truzzi S, Tutone A, Ubach S, van Scherpenberg J, Vazquez Acosta M, Ventura S, Verguilov V, Viale I, Vigorito CF, Vitale V, Vovk I, Walter R, Will M, Wunderlich C, Yamamoto T, Zarić D, Hiroshima N, and Kohri K

Abstract

Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10^{-28}  cm^{3} s^{-1} at 1 TeV and ⟨σv⟩≲1×10^{-25}  cm^{3} s^{-1} at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

Published
2023
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14. In Vitro Studies of Pegylated Magnetite Nanoparticles in a Cellular Model of Viral Oncogenesis: Initial Studies to Evaluate Their Potential as a Future Theranostic Tool.

Author

Principe G, Lezcano V, Tiburzi S, Miravalles AB, Rivero PS, Montiel Schneider MG, Lassalle V, and González-Pardo V

Abstract

Magnetic nanosystems represent promising alternatives to the traditional diagnostic and treatment procedures available for different pathologies. In this work, a series of biological tests are proposed, aiming to validate a magnetic nanoplatform for Kaposi's sarcoma treatment. The selected nanosystems were polyethylene glycol-coated iron oxide nanoparticles (MAG.PEG), which were prepared by the hydrothermal method. Physicochemical characterization was performed to verify their suitable physicochemical properties to be administered in vivo. Exhaustive biological assays were conducted, aiming to validate this platform in a specific biomedical field related to viral oncogenesis diseases. As a first step, the MAG.PEG cytotoxicity was evaluated in a cellular model of Kaposi's sarcoma. By phase contrast microscopy, it was found that cell morphology remained unchanged regardless of the nanoparticles' concentration (1-150 µg mL -1 ). The results, arising from the crystal violet technique, revealed that the proliferation was also unaffected. In addition, cell viability analysis by MTS and neutral red assays revealed a significant increase in metabolic and lysosomal activity at high concentrations of MAG.PEG (100-150 µg mL -1 ). Moreover, an increase in ROS levels was observed at the highest concentration of MAG.PEG. Second, the iron quantification assays performed by Prussian blue staining showed that MAG.PEG cellular accumulation is dose dependent. Furthermore, the presence of vesicles containing MAG.PEG inside the cells was confirmed by TEM. Finally, the MAG.PEG steering was achieved using a static magnetic field generated by a moderate power magnet. In conclusion, MAG.PEG at a moderate concentration would be a suitable drug carrier for Kaposi's sarcoma treatment, avoiding adverse effects on normal tissues. The data included in this contribution appear as the first stage in proposing this platform as a suitable future theranostic to improve Kaposi's sarcoma therapy.

Published
2023
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