Article
Astronomy & Astrophysics
A. Rossi, D. D. Frederiks, D. A. Kann, M. De Pasquale, E. Pian, G. Lamb, P. D'Avanzo, L. Izzo, A. J. Levan, D. B. Malesani, A. Melandri, A. Nicuesa Guelbenzu, S. Schulze, R. Strausbaugh, N. R. Tanvir, L. Amati, S. Campana, A. Cucchiara, G. Ghirlanda, M. Della Valle, S. Klose, R. Salvaterra, R. L. C. Starling, G. Stratta, A. E. Tsvetkova, S. D. Vergani, A. D'Ai, D. Burgarella, S. Covino, V D'Elia, A. de Ugarte Postigo, H. Fausey, J. P. U. Fynbo, F. Frontera, C. Guidorzi, K. E. Heintz, N. Masetti, F. Maiorano, C. G. Mundell, S. R. Oates, M. J. Page, E. Palazzi, J. Palmerio, G. Pugliese, A. Rau, A. Saccardi, B. Sbarufatti, D. S. Svinkin, G. Tagliaferri, A. J. van der Horst, D. J. Watson, M. Ulanov, K. Wiersema, D. Xu, J. Zhang
Summary: This study presents a detailed follow-up of the high-redshift GRB210905A. The results demonstrate that the energy release and afterglow luminosity of this burst are consistent with those of less distant bursts, indicating that the powering mechanisms and progenitors do not evolve significantly with redshift.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Amit Kumar Ror, Rahul Gupta, Martin Jelinek, Shashi Bhushan Pandey, A. J. Castro-Tirado, Y-D Hu, Alzbeta Malenakova, Jan Strobl, Christina C. Thone, Rene Hudec, Sergey Karpov, Amit Kumar, A. Aryan, S. R. Oates, E. Fernandez-Garcia, C. Perez del Pulgar, M. D. Caballero-Garcia, A. Castellon, I. M. Carrasco-Garcia, I Perez-Garcia, A. J. Reina Terol, F. Rendon
Summary: This study presents a detailed analysis of the prompt emission and early optical afterglow of two very-high-energy (VHE) detected bursts, GRB 201015A and GRB 201216C. The early optical observations reveal a smooth bump in the light curves, indicating the onset of synchrotron emission from an external forward shock.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
S. Giarratana, L. Rhodes, B. Marcote, R. Fender, G. Ghirlanda, M. Giroletti, L. Nava, J. M. Paredes, M. E. Ravasio, M. Ribo, M. Patel, J. Rastinejad, G. Schroeder, W. Fong, B. P. Gompertz, A. J. Levan, P. O'Brien
Summary: This study investigates the afterglow phase of GRB 201015A through radio, optical, and X-ray observations. Several conclusions are drawn, including the possibility of this gamma-ray burst being seen on-axis and the presence of a reverse shock component during the early stage of the burst.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Jie Zhu, Bo-Qiang Ma
Summary: Previous research indicates high-energy neutrinos appear about 300 seconds earlier than low-energy photons in the source reference system, possibly accompanied by high-energy photons. Analysis of observational data reveals high-energy photon events occurring near gamma-ray burst sources, providing further support for the hypothesis of synchronous emission of neutrinos and high-energy photons.
Article
Astronomy & Astrophysics
Xue-Zhao Chang, Hou-Jun Lu, Xing Yang, Jia-Ming Chen, En-Wei Liang
Summary: Long-duration GRB 211211A without supernova emission at a low redshift suggests it originates from a binary compact star merger. The data from the Fermi mission show that a 2SBPL+BB model fits the spectra of the prompt emission well. The inferred Lorentz factors and magnetization factors indicate the presence of Poynting-flux component in the outflow and suggest contributions from vv(SIC) annihilation and the Blandford-Znajek mechanisms in the relativistic jet.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Jie Zhu, Bo-Qiang Ma
Summary: Previous studies have shown that high-energy photons appear earlier than low-energy photons at the source of GRBs, but in the scenario of energy-dependent light speed variation, high-energy photons travel slower than low-energy photons and are typically detected later. Recent research analyzing high-energy photon events observed earlier than low-energy photons from FGST supports the pre-burst scenario of high-energy photons from GRBs and the energy dependence of light speed.
Article
Physics, Nuclear
Qi-Ling Chen, Pei-Jin Hu, Jing-Jing Su, Ming-Ming Kang, Yi-Qing Guo, Tian-Lu Chen, Dan-Zeng Luo-Bu, Yu-fan Fan, You-Liang Feng, Qi Gao, Quan-Bu Gou, Hong-Bo Hu, Hai-Jin Li, Cheng Liu, Mao-Yuan Liu, Wei Liu, Xiang-Li Qian, Bing-Qiang Qiao, Hui-Ying Sun, Xu Wang, Zhen Wang, Guang-Guang Xin, Yu-Hua Yao, Qiang Yuan, Yi Zhang, Bing Zhao
Summary: The detection of SGRBs in the TeV energy range is crucial for understanding radiation mechanisms and exploring new physics. However, current experiments have not observed SGRBs in this energy range due to their short duration and experimental limitations. New experiments with advanced technology are needed to detect the high-energy emissions from SGRBs.
Article
Astronomy & Astrophysics
Melissa Diamond, Damiano F. G. Fiorillo, Gustavo Marques-Tavares, Edoardo Vitagliano
Summary: New feebly interacting particles from a supernova core could produce γ-rays by subsequent decays, but the decay photons may not escape and can instead form a plasma shell. This means axionlike particles with few 10 MeV masses and a two-photon coupling of a few 10(-10) GeV-1 may still exist. However, this new window is closed as the expected sub-MeV photons were not observed from SN 1987A and the Pioneer Venus Orbiter.
Article
Astronomy & Astrophysics
Jia Ren, Yun Wang, Lu-Lu Zhang, Zi-Gao Dai
Summary: In this paper, the dynamics and radiation physics of the afterglow of the rare event GRB 221009A are modeled in detail. By introducing a top-hat jet in an environment dominated by stellar winds, the observations of the afterglow associated with GRB 221009A over the first week are explained. The model predicts a luminous very high energy afterglow for GRB 221009A based on the synchrotron self-Compton process.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Hao Li, Bo-Qiang Ma
Summary: It has been reported that the Large High Altitude Air Shower Observatory (LHAASO) has observed extremely high-energy photons from GRB 221009A, with the maximum energy reaching 18 TeV. This observation is challenging due to the absorption of these photons by extragalactic background light and the weak flux. Therefore, a potential explanation for this phenomenon is proposed based on Lorentz invariance violation induced threshold anomaly in the process yy -> e-e+.
ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Lu-Lu Zhang, Jia Ren, Yun Wang, En-Wei Liang
Summary: By analyzing the observational data of GRBs 201015A and 201216C, researchers find that their VHE gamma-ray afterglows are produced by the synchrotron radiation of relativistic electrons in their jets. It is also discovered that the jet of GRB 201015A is slower and surrounded by a very dense medium, while the jet of GRB 201216C is faster and surrounded by a moderate density medium. The VHE gamma-ray afterglow of GRB 201216C has a high peak luminosity and can be detected with the MAGIC telescopes.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
L. Rhodes, A. J. van der Horst, R. Fender, D. R. Aguilera-Dena, J. S. Bright, S. Vergani, D. R. A. Williams
Summary: We present the results of a radio observing campaign on GRB 201216C, combined with publicly available optical and X-ray data. The detection of very high energy (VHE, >100 GeV) emission by MAGIC makes this the fifth VHE GRB at the time of publication. Comparison between the optical and X-ray light curves show that GRB 201216C is a dark GRB, i.e. the optical emission is significantly absorbed and is fainter than expected from the X-ray detections.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Alice K. Harding, Christo Venter, Constantinos Kalapotharakos
Summary: Air-Cherenkov telescopes have detected pulsations at energies above 50 GeV from several Fermi pulsars, indicating the presence of very-high-energy emissions. Spectral modeling suggests three distinct VHE components, including SC, SSC, and ICS, each originating from different emission mechanisms. Detection of these components from additional pulsars is possible with advanced observatories like the High Altitude Water Cherenkov Observatory and Cherenkov Telescope Array.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Anna Y. Q. Ho, Daniel A. Perley, Yuhan Yao, Dmitry Svinkin, A. de Ugarte Postigo, R. A. Perley, D. Alexander Kann, Eric Burns, Igor Andreoni, Eric C. Bellm, Elisabetta Bissaldi, Joshua S. Bloom, Thomas G. Brink, Richard Dekany, Andrew J. Drake, Jose Feliciano Agui Fernandez, Alexei Filippenko, Dmitry Frederiks, Matthew J. Graham, Boyan A. Hristov, Mansi M. Kasliwal, S. R. Kulkarni, Harsh Kumar, Russ R. Laher, Alexandra L. Lysenko, Bagrat Mailyan, Christian Malacaria, A. A. Miller, S. Poolakkil, Reed Riddle, Anna Ridnaia, Ben Rusholme, Volodymyr Savchenko, Jesper Sollerman, Christina Thoene, Anastasia Tsvetkova, Mikhail Ulanov, Andreas von Kienlin
Summary: A search using the ZTF has discovered seven optical transients resembling on-axis LGRB afterglows. Spectroscopy confirmed the cosmological distances of six events and identified potential associated LGRBs. Three events had no counterpart, possibly due to missed detections by high-energy satellites or intrinsic subluminosity.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Xiao-Li Huang, Ze-Rui Wang, Ruo-Yu Liu, Xiang-Yu Wang, En-Wei Liang
Summary: The study shows that the SSC emission from GRB afterglows in homogeneous and wind environments exhibit different characteristics and trends. Additionally, higher SSC flux is observed in high-density environments, but at the same time, more severe internal gamma-gamma absorption is also present.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Hamid Hamidani, Kenta Kiuchi, Kunihito Ioka
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Kazuya Takahashi, Kunihito Ioka
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Hamid Hamidani, Kunihito Ioka
Summary: Research on the propagation of short gamma-ray burst jets produced in binary neutron star mergers shows that they differ from those in collapsars by traveling through the expanding ambient medium of merger ejecta. The models presented have been tested in numerical simulations and are consistent in various aspects, providing useful estimates for electromagnetic counterparts to gravitational waves.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Ryuichi Takahashi, Kunihito Ioka, Asuka Mori, Koki Funahashi
Summary: Through hydrodynamic simulations, the statistical properties of cosmological dispersion measure were studied, with analytical fitting functions provided for the free-electron power spectrum. By analyzing mock sky maps and source redshift distributions, the cosmological features of fast radio bursts were explored, expecting confirmation in future observations when more FRBs are available.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Edwan Preau, Kunihito Ioka, Peter Meszaros
Summary: The theoretical model proposed in the study describes the structuring of a relativistic jet propagating through the ejecta of a binary neutron star merger event, taking into account the effects of neutron conversion-diffusion. This results in an increased baryon load structure of the outer jet with an energy distribution proportional to the off-axis angle.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Wataru Ishizaki, Kunihito Ioka, Kenta Kiuchi
Summary: The X-ray counterpart to the binary neutron star merger and gravitational-wave event GW170817 shows evidence of a fallback accretion process, providing insights into the afterglow emission from the kilonova/macronova ejecta. Future observations are needed to further investigate this model.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Article
Astronomy & Astrophysics
Wataru Ishizaki, Kenta Kiuchi, Kunihito Ioka, Shinya Wanajo
Summary: By studying the fallback accretion with r-process heating, this research shows that the usual fallback rate is halted by the heating due to pressure gradients accelerating ejecta beyond the escape velocity. The characteristic halting timescale is around 10(4)-10(8) seconds for r-process heating like GW170817, and future observations of fallback halting could constrain the r-process heating on the scale of a year.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Tomoki Wada, Kunihito Ioka, Bing Zhang
Summary: The study suggests that FRB 121102 can be interpreted as an interacting neutron star binary system with an orbital period of around 159 days. By introducing eccentricity into the orbit, new modes of the binary comb model are identified and applied to interpret the source. These models expand the applicable parameter space, allowing for different companion stars like massive stars, black holes, or supermassive black holes.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Masato Shirasaki, Ryuichi Takahashi, Ken Osato, Kunihito Ioka
Summary: By cross-correlating the foreground dark matter haloes with their known redshifts, valuable cosmological information for future surveys of fast radio bursts (FRBs) can be obtained. This has significant implications for FRB cosmology and calls for further research.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Kazuya Takahashi, Kunihito Ioka, Yutaka Ohira, Hendrik J. van Eerten
Summary: This study reveals the relationship between electromagnetic waves and gravitational waves by observing the changes in spectral slope during particle acceleration in both relativistic and non-relativistic scenarios. The relativistic spectral slope shows a steep change near the peak time of the light curve and approaches the non-relativistic limit after about 10 times the peak time.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Hamid Hamidani, Kunihito Ioka
Summary: The cocoon formed by a jet in ambient matter is an important factor in gamma-ray bursts (GRBs). This study focuses on the differences between short GRBs (sGRBs) and collapsars, with sGRBs being produced from the merger of neutron stars. Using simulations, the researchers find that the expansion of the ambient matter influences the cocoon mass, with only a small fraction escaping in sGRBs compared to collapsars. The analysis suggests that the observed cooling emission is unlikely to be from the sGRB-jet heated cocoon associated with the gravitational wave event GW170817.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tomoki Wada, Kunihito Ioka
Summary: A radiation plasma fireball near the surface of a neutron star expands and produces photon emission and relativistic matter outflow along magnetic field lines. We classify the evolution of the expanding fireball into five cases, taking into account key processes such as lateral diffusion of photons, effects of strong magnetic field, baryon loading, and radiative acceleration. Applying this model to magnetar bursts with FRBs, we show that the burst radiation can accelerate the outflow to high-Lorentz factor with sufficient energy to power FRBs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
B. Theodore Zhang, Kohta Murase, Kunihito Ioka, Deheng Song, Chengchao Yuan, Peter Meszaros
Summary: The detection of hyper-bright gamma-ray burst (GRB) 221009A allows us to investigate the nature of GRB emission and the origin of very high-energy gamma rays. Using Fermi Large Area Telescope (Fermi-LAT) data, we analyze the GeV-TeV emission of this burst within the framework of the external reverse-shock model. Our findings suggest that the early emission in the 1-10 GeV range can be explained by the external inverse-Compton mechanism, in addition to the synchrotron self-Compton component. We also propose that the proton synchrotron emission from accelerated ultrahigh-energy cosmic rays (UHECRs) is detectable and may explain TeV photons detected by LHAASO or constrain the UHECR acceleration mechanism.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Hamid Hamidani, Kunihito Ioka
Summary: In the GW170817 gravitational wave event, a 10-hour gap without detection of the cocoon was observed before electromagnetic observations. The cocoon is formed by a short gamma-ray burst jet passing through the ejecta of a neutron star merger. Our simulations and calculations show that the cocoon emits strong UV radiation, outshining the r-process kilonova/macronova at early times. The relativistic velocity of the cocoon can be measured, and energetic cocoons may be detected as X-ray flashes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Kunihito Ioka
ASTROPHYSICAL JOURNAL LETTERS
(2020)