Results 1 to 10 of about 8,426 (297)

Fast X-Ray Transients in NuSTAR Data

The Astrophysical Journal
Fast X-ray transients (FXTs) are flashes of X-rays that last for a few hundreds of seconds to a few hours. An enigmatic population of these transients that did not have a clear origin has been known for several decades, mostly found serendipitously in ...
Murray Brightman, Joahan Castañeda Jaimes, Daniel Stern, Brian Grefenstette   +3 more
doaj   +1 more source

Absorption of Gamma-Ray Burst X-Ray Afterglows by the Missing Baryons: Confronting Observations with Cosmological Simulations

The Astrophysical Journal, 2023
A large fraction of the baryons at low redshift are undetected and likely reside in the tenuous, hot intergalactic medium (IGM). One way to probe the missing baryons is through their absorption of bright sources.
Matan Grauer, Ehud Behar
doaj   +1 more source

Multi-instrument Search for Gamma-Ray Counterpart of X-Ray Transients Detected by EP/WXT

The Astrophysical Journal Letters
As a soft X-ray imager with an unprecedentedly large field of view, Einstein Probe (EP)/Wide-field X-ray Telescope (WXT) has detected many (fast) X-ray transients, whose nature is very intriguing.
Yan-Qiu Zhang, Wang-Chen Xue, Jin-Peng Zhang, Ce Cai, Shao-Lin Xiong, Cheng-Kui Li, Yuan Liu, Chen-Wei Wang, Hao-Xuan Guo, Shuo Xiao, Wen-Jun Tan, Chao Zheng, Jia-Cong Liu, Sheng-Lun Xie, Peng Zhang, Wen-Long Zhang, Yue Wang, Zheng-Hang Yu, Yang-Zhao Ren, Ping Wang, Yue Huang, Xiao-Bo Li, Xiao-Yun Zhao, Shi-Jie Zheng, Zhen Zhang, Shu-Xu Yi, Li-Ming Song, Shuang-Nan Zhang   +27 more
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The Formation of Hard Very High Energy Spectra from Gamma-ray Burst Afterglows via Two-zone Synchrotron Self-Compton Emission

The Astrophysical Journal, 2023
Electron Compton scattering of target photons into the gamma-ray energy band (inverse Compton scattering; IC) is commonly expected to dominate the very high energy (VHE) spectra in gamma-ray bursts (GRBs) especially during the afterglow phase.
Dmitry Khangulyan, Andrew M. Taylor, Felix Aharonian   +2 more
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Fermi-LAT Detection of a Transient γ-Ray Source in the Direction of a Distant Blazar B3 1428+422 at z = 4.72 [PDF]

The Astrophysical Journal Letters, 2018
Abstract We report the detection of a transient γ-ray source in the direction of B3 1428+422 (z = 4.72) by analyzing the 110-month Fermi-LAT Pass 8 data. The new transient γ-ray source is far away from the Galactic plane and has a rather soft spectrum, in agreement with being a high redshift blazar.
Neng-Hui Liao, Shang Li, Yi-Zhong Fan
openaire   +2 more sources

EP240801a/XRF 240801B: An X-Ray Flash Detected by the Einstein Probe and the Implications of Its Multiband Afterglow

The Astrophysical Journal Letters
We present multiband observations and analysis of EP240801a, a low-energy, extremely soft gamma-ray burst (GRB) discovered on 2024 August 1 by the Einstein Probe (EP) satellite with a weak contemporaneous signal also detected by the Fermi Gamma-ray Burst
Shuai-Qing Jiang, Dong Xu, Agnes P. C. van Hoof, Wei-Hua Lei, Yuan Liu, Hao Zhou, Yong Chen, Shao-Yu Fu, Jun Yang, Xing Liu, Zi-Pei Zhu, Alexei V. Filippenko, Peter G. Jonker, A. S. Pozanenko, He Gao, Xue-Feng Wu, Bing Zhang, Gavin P Lamb, Massimiliano De Pasquale, Shiho Kobayashi, Franz Erik Bauer, Hui Sun, Giovanna Pugliese, Jie An, Valerio D’Elia, Johan P. U. Fynbo, WeiKang Zheng, Alberto J. Castro-Tirado, Yi-Han Iris Yin, Yuan-Chuan Zou, Adam T. Deller, N. S. Pankov, A. A. Volnova, A. S. Moskvitin, O. I. Spiridonova, D. V. Oparin, V. Rumyantsev, O. A. Burkhonov, Sh. A. Egamberdiyev, V. Kim, M. Krugov, A. M. Tatarnikov, R. Inasaridze, Andrew J. Levan, Daniele Bjørn Malesani, Maria E. Ravasio, Jonathan Quirola-Vásquez, Joyce N. D. van Dalen, Javi Sánchez-Sierras, Daniel Mata Sánchez, Stuart P. Littlefair, Jennifer A. Chacón, Manuel A. P. Torres, Ashley A. Chrimes, Nikhil Sarin, Antonio Martin-Carrillo, Vik Dhillon, Yi Yang, Thomas G. Brink, Rebecca L. Davies, Sheng Yang, Amar Aryan, Ting-Wan Chen, Albert K. H. Kong, Wen-Xiong Li, Rui-Zhi Li, Jirong Mao, Ignacio Pérez-García, Emilio J. Fernández-García, Moira Andrews, Joseph Farah, Zhou Fan, Estefania Padilla Gonzalez, D. Andrew Howell, Dieter Hartmann, Jing-Wei Hu, Páll Jakobsson, Cheng-Kui Li, Zhi-Xing Ling, Curtis McCully, Megan Newsome, Benjamin Schneider, Kaew Samaporn Tinyanont, Ning-Chen Sun, Giacomo Terreran, Qing-Wen Tang, Wen-Xin Wang, Jing-Jing Xu, Wei-Min Yuan, Bin-Bin Zhang, Hai-Sheng Zhao, Juan Zhang   +91 more
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The Nature of Optical Afterglows without Gamma-Ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling

The Astrophysical Journal
In the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs).
Maggie L. Li, Anna Y. Q. Ho, Geoffrey Ryan, Daniel A. Perley, Gavin P. Lamb, Nayana A.J., Igor Andreoni, G. C. Anupama, Eric C. Bellm, Edo Berger, Joshua S. Bloom, Eric Burns, Ilaria Caiazzo, Poonam Chandra, Michael W. Coughlin, Kareem El-Badry, Matthew J. Graham, Mansi Kasliwal, Garrett K. Keating, S. R. Kulkarni, Harsh Kumar, Frank J. Masci, Richard A. Perley, Josiah Purdum, Ramprasad Rao, Antonio C. Rodriguez, Ben Rusholme, Nikhil Sarin, Jesper Sollerman, Gokul P. Srinivasaragavan, Vishwajeet Swain, Zachary Vanderbosch   +31 more
doaj   +1 more source

A Search for Gamma-Ray Emission from Variable or Transient Galactic Radio Sources

, 2013
2012 Fermi Symposium proceedings - eConf ...
Shrader, C. R., Macomb, D. J.
openaire   +2 more sources

AGILE Observations of Variable and transient $\gamma$-ray sources in the Galactic plane, Catalog improvements [PDF]

Proceedings of 25th Texas Symposium on Relativistic Astrophysics — PoS(Texas 2010), 2011
AGILE has provided continuous monitoring of the Galactic plane in γ-rays in more than three years of operation [1]. Thanks to its sensitivity at energies near 100 MeV, AGILE has observed variability and transient behavior in a number of sources. Simultaneous hard X-ray coverage, rapid alerts to the astronomical community, and multiwavelength campaigns ...
openaire   +2 more sources

Triggering the Untriggered: The First Einstein Probe-detected Gamma-Ray Burst 240219A and Its Implications

The Astrophysical Journal Letters
The Einstein Probe (EP) achieved its first detection and localization of a bright X-ray flare, EP240219a, on 2024 February 19, during its commissioning phase.
Yi-Han Iris Yin, Bin-Bin Zhang, Jun Yang, Hui Sun, Chen Zhang, Yi-Xuan Shao, You-Dong Hu, Zi-Pei Zhu, Dong Xu, Li An, He Gao, Xue-Feng Wu, Bing Zhang, Alberto Javier Castro-Tirado, Shashi B. Pandey, Arne Rau, Weihua Lei, Wei Xie, Giancarlo Ghirlanda, Luigi Piro, Paul O’Brien, Eleonora Troja, Peter Jonker, Yun-Wei Yu, Jie An, Run-Chao Chen, Yi-Jing Chen, Xiao-Fei Dong, Rob Eyles-Ferris, Zhou Fan, Shao-Yu Fu, Johan P. U. Fynbo, Xing Gao, Yong-Feng Huang, Shuai-Qing Jiang, Ya-Hui Jiang, Yashaswi Julakanti, Erik Kuulkers, Qing-Hui Lao, Dongyue Li, Zhi-Xing Ling, Xing Liu, Yuan Liu, Jia-Yu Mou, Xin Pan, Varun, Daming Wei, Qinyu Wu, Muskan Yadav, Yu-Han Yang, Weimin Yuan, Shuang-Nan Zhang   +51 more
doaj   +1 more source