Results 41 to 50 of about 277 (132)

The Energy Budget in the Jet of High-frequency Peaked BL Lacertae Objects

The Astrophysical Journal
Energy equipartition and the energy budget in the jet are important issues for the radiation mechanism of blazars. Early work predominantly concentrated on flat-spectrum radio quasars and a limited number of BL Lacertae (BL Lac) objects.
X. Z. Zhao, H. Y. Yang, Y. G. Zheng, S. J. Kang   +3 more
doaj   +1 more source

Very-high-energy gamma-ray intranight variability from BL Lacertae during the extreme flaring state of 2022

Astronomy & Astrophysics
Context. BL Lacertae (BL Lac), the archetypal blazar of its subclass and one of the most studied blazars of recent decades, has undergone a series of major multi-wavelength outbursts since 2020, resulting in its highest recorded γ-ray flare to date ...
Abe K., Abe S., Abhishek A., Acero F., Aguasca-Cabot A., Agudo I., Alispach C., Ambrosino D., Ambrosino F., Antonelli L. A., Aramo C., Arbet-Engels A., Arcaro C., Arnesen T. T. H., Aubert P., Baktash A., Balbo M., Bamba A., Baquero Larriva A., Barres de Almeida U., Barrio J. A., Barrios Jiménez L., Batkovic I., Baxter J., Becerra González J., Bernete J., Berti A., Bissaldi E., Blanch O., Bonnoli G., Bordas P., Briscioli A., Brunelli G., Buces J., Bulgarelli A., Burelli I., Burmistrov L., Cardillo M., Caroff S., Carosi A., Carraro R., Cassol F., Cerasole D., Cerviño Cortínez A., Chai Y., Chon G., Chytka L., Cicciari G. M., Contreras J. L., Cortina J., Costantini H., Croisonnier M., Dalchenko M., D’Amico G., Da Vela P., Dazzi F., De Angelis A., de Bony de Lavergne M., Del Burgo R., Delgado C., Delgado Mengual J., della Volpe D., De Lotto B., Del Peral L., de Menezes R., De Palma G., de Souza V., Díaz C., Di Bella L., Di Piano A., Di Pierro F., Di Tria R., Di Venere L., Dominis Prester D., Donini A., Dorner D., Eisenberger L., Elsässer D., Emery G., Feligioni L., Ferrarotto F., Fiasson A., Foffano L., Fukazawa Y., Gallozzi S., Garcia López R., Garcia Soto S., Gasbarra C., Gasparrini D., Giesbrecht Paiva J., Giglietto N., Giordano F., Godinovic N., Gradetzke T., Grau R., Green J., Grolleron G., Gunji S., Günther P., Hackfeld J., Hadasch D., Hashizume M., Hassan T., Hayashi K., Heckmann L., Heller M., Herrera Llorente J., Hiroshima N., Hoffmann D., Horns D., Houles J., Hrupec D., Imazawa R., Inada T., Inoue S., Ioka K., Iori M., Itokawa T., Iuliano A., Jahanvi J., Jimenez Martinez I., Jimenez Quiles J., Jorge Rodrigo I., Jurysek J., Kagaya M., Karas V., Katagiri H., Kerszberg D., Kiyomoto T., Kobayashi Y., Kohri K., Kornecki P., Kubo H., Kushida J., Lacave B., Lainez M., Lamastra A., Lemoigne L., Linhoff M., Lombardi S., Longo F., López-Coto R., López-Oramas A., Loporchio S., Lozano Bahilo J., Lucarelli F., Luciani H., Luque-Escamilla P. L., Makariev M., Mallamaci M., Mandat D., Mannheim K., Marini F., Mariotti M., Marquez P., Marsella G., Martí J., Martinez O., Martínez G., Martínez M., Massa M., Mazin D., Méndez-Gallego J., Menon S., Mestre Guillen E., Miceli D., Miener T., Miranda J. M., Molero Gonzalez M., Molina E., Montaruli T., Moralejo A., Morselli A., Moya V., Müller A. L., Muraishi H., Nagataki S., Nakamori T., Neronov A., Nieto Castaño D., Nievas Rosillo M., Nikolic L., Noda K., Novotny V., Nozaki S., Ohishi M., Ohtani Y., Okumura A., Orito R., Orsini L., Otero-Santos J., Ottanelli P., Palatiello M., Panebianco G., Paneque D., Paoletti R., Paredes J. M., Pech M., Pecimotika M., Peresano M., Perrotta F., Pfeifle F., Pihet M., Pirola G., Plard C., Podobnik F., Polo M., Pozo-Gonzaléz C., Prandini E., Rainò S., Rando R., Rhode W., Ribó M., Rodriguez Fernandez G., Rodríguez Frías M. D., Roy A., Ruina A., Ruiz-Velasco E., Saito T., Sakurai S., Sanchez D. A., Sano H., Santos Moura E., Šarić T., Sato Y., Saturni F. G., Savchenko V., Schiavone F., Schussler F., Schweizer T., Seglar Arroyo M., Silvestri G., Simongini A., Sitarek J., Sliusar V., Sofia I., Strišković J., Strzys M., Suda Y., Sunny A., Tajima H., Takahashi M., Takeishi R., Tanaka S. J., Tateishi D., Tavernier T., Temnikov P., Terada Y., Terauchi K., Terzic T., Teshima M., Tluczykont M., Tomura T., Torres D. F., Tramonti F., Travnicek P., Tripodo G., Tutone A., Vacula M., Vázquez Acosta M., Verna G., Viale I., Viana A., Vigliano A., Vigorito C. F., Visentin E., Vitale V., Voutsinas G., Vovk I., Vuillaume T., Walter R., Yamamoto T., Yamazaki R., Yao Y., Yoshida T., Yoshikoshi T., Zhang W., Zywucka N., Aceituno F., Acosta-Pulido J. A., Casanova V., Escudero Pedrosa J., Fallah Ramazani V., Jormanainen J., Jorstad S., Keating G., Kouch P. M., Gurwell M., Lähteenmäki A., Lindfors E., Marscher A., Morcuende D., Myserlis I., Nilsson K., Ortega Hunter C. A., Rao R., Sota A., Tornikoski M., Zhang H.   +298 more
doaj   +1 more source

Systematic Search for and Study of Short-timescale Flare Structures in BL Lac Object Gamma-Ray Emission

The Astrophysical Journal
We present here the first systematic search of short-timescale γ -ray flares from 29 high Galactic latitude BL Lac objects over 14 yr of Fermi Large Area Telescope data. Using a combined Bayesian Blocks and HOP algorithm, we identified seven high-quality
Jinjie Yu, Nan Ding, Junhui Fan, Yunyong Tang, Jin Cao   +4 more
doaj   +1 more source

Classification of Blazar Candidates of Unknown Type in Fermi 4LAC by Unanimous Voting from Multiple Machine-learning Algorithms

The Astrophysical Journal, 2023
The Fermi fourth catalog of active galactic nuclei (AGNs) data release 3 (4LAC-DR3) contains 3407 AGNs, out of which 755 are flat spectrum radio quasars (FSRQs), 1379 are BL Lacertae objects (BL Lac objects), 1208 are blazars of unknown (BCUs) type ...
A. Agarwal
doaj   +1 more source

Long-term Optical Spectroscopic Variability of BL Lacertae Object AO 0235+164

The Astrophysical Journal
The changing-look (CL) phenomenon in active galactic nuclei (AGNs) poses a significant challenge to the unified model. As a special subclass of AGN, blazars provide valuable insights.
W. T. He, D. R. Xiong, S. J. Kang, Y. G. Zheng   +3 more
doaj   +1 more source

Flux and Spectral Variability of High-Energy-Peaked BL Lacertae Objects in the 0.3–10 keV Band

Galaxies
BL Lacertae objects (BL Lacs) are active galactic nuclei notable for beamed emission generated in the relativistic jets, forming a small angle with respect to our line-of-sight.
Bidzina Kapanadze
doaj   +1 more source

Rapid Optical Flares in the Blazar OJ 287 on Intraday Timescales with TESS

The Astrophysical Journal, 2023
We have analyzed the optical light curves of the blazar OJ 287 obtained with the Transiting Exoplanet Survey Satellite over about 80 days from 2021 October 13 to December 31, with an unprecedented sampling of 2 minutes.
Shubham Kishore, Alok C. Gupta, Paul J. Wiita   +2 more
doaj   +1 more source

BL Lacertae objects and the extragalactic γ-ray background [PDF]

Research in Astronomy and Astrophysics, 2011
12 pages, 4 figures ...
Li, Fan, Cao, Xinwu
openaire   +2 more sources

Highly Polarized Optically Selected BL Lacertae Objects [PDF]

The Astrophysical Journal, 2007
9 pages, 3 figures, 2 ...
Smith, Paul S., Williams, G. Grant, Schmidt, Gary D., Diamond-Stanic, Aleksandar M., Means, Dennis L.   +4 more
openaire   +2 more sources

BeppoSAX observations of 1-Jy BL Lacertae objects -- II [PDF]

Monthly Notices of the Royal Astronomical Society, 2004
We present new BeppoSAX LECS and MECS observations, covering the energy range 0.1 - 10 keV (observer's frame), of four BL Lacertae objects selected from the 1 Jy sample. All sources display a flat (alpha_x ~ 0.7) X-ray spectrum, which we interpret as inverse Compton emission.
PADOVANI P., COSTAMANTE L., GIOMMI P., GHISELLINI G., Celotti, Anna Lisa, WOLTER A.   +5 more
openaire   +4 more sources