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19912026
Showing 2021 · astro-ph.HEShow all

18 papers · 2 filters

astro-ph.HE2021★ 36 cited

Collimation of the relativistic jet in the quasar 3C 273

Hiroki Okino, Kazunori Akiyama, Keiichi Asada +32

The collimation of relativistic jets launched from the vicinity of supermassive black holes (SMBHs) at the centers of active galactic nuclei (AGN) is one of the key questions to un…

astro-ph.HE2021★ 9 cited

Proposed Lunar Measurements of -Process Radioisotopes to Distinguish Origin of Deep-sea 244Pu

Xilu Wang, Adam M. Clark, John Ellis +6

244Pu has recently been discovered in deep-sea deposits spanning the past 10 Myr, a period that includes two 60Fe pulses from nearby supernovae. 244Pu is among the heaviest -pro…

astro-ph.HE2021

Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. V. Space and ground millimeter-VLBI imaging of OJ 287

Jose L. Gómez, Efthalia Traianou, Thomas P. Krichbaum +27

We present the first polarimetric space VLBI observations of OJ 287, observed with RadioAstron at 22 GHz during a perigee session on 2014 April 4 and five near-in-time snapshots, t…

astro-ph.HE2021★ 18 cited

The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale

Kaushik Satapathy, Dimitrios Psaltis, Feryal Ozel +235

The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center o…

astro-ph.HE2021★ 103 cited

Diffuse Supernova Neutrino Background Search at Super-Kamiokande

Kamiokande Collaboration, K. Abe, C. Bronner +216

A new search for the diffuse supernova neutrino background (DSNB) flux has been conducted at Super-Kamiokande (SK), with a -ktonday exposure from its fourth…

astro-ph.HE2021★ 44 cited

Limits on astrophysical antineutrinos with the KamLAND experiment

S. Abe, S. Asami, A. Gando +66

We report on a search for electron antineutrinos () from astrophysical sources in the neutrino energy range 8.3 to 30.8 MeV with the KamLAND detector. In an exposure of 6.…

astro-ph.HE2021★ 49 cited

Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017

MAGIC Collaboration, V. A. Acciari, S. Ansoldi +284

We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with special focus on the multi-band flux co…

astro-ph.HE2021★ 18 cited

Repeated pattern of gamma-ray flares in the lightcurve of the blazar 3C 279

D. Blinov, S. G. Jorstad, V. M. Larionov +10

The optical polarization plane of some blazars occasionally exhibits smooth hundred degree long rotations. Multiple theoretical models have been proposed to explain the nature of s…

astro-ph.HE2021★ 89 cited

The Polarized Image of a Synchrotron Emitting Ring of Gas Orbiting a Black Hole

Ramesh Narayan, Daniel C. M. Palumbo, Michael D. Johnson +237

Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field i…

astro-ph.HE2021★ 683 cited

First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon

The Event Horizon Telescope Collaboration

Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotr…

astro-ph.HE2021★ 39 cited

X-ray spectral components of the blazar and binary black hole candidate OJ 287 (2005-2020)

S. Komossa, D. Grupe, M. L. Parker +12

We present a comprehensive analysis of all XMM-Newton spectra of OJ 287 spanning 15 years of X-ray spectroscopy of this bright blazar. We also report the latest results from our de…

astro-ph.HE2021★ 469 cited

First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

The Event Horizon Telescope Collaboration

In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observat…

astro-ph.HE2021★ 50 cited

Frequency and Time Dependence of Linear Polarization in Turbulent Jets of Blazars

Alan P. Marscher, Svetlana G. Jorstad

Time-variable polarization is an extremely valuable observational tool to probe the dynamical physical conditions of blazar jets. Since 2008, we have been monitoring the flux and l…

astro-ph.HE2021★ 41 cited

The complex variability of blazars: Time-scales and periodicity analysis in S4 0954+65

C. M. Raiteri, M. Villata, V. M. Larionov +3

Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Trans…

astro-ph.HE2021★ 18 cited

A detailed kinematic study of 3C 84 and its connection to Gamma-rays

Jeffrey A. Hodgson, Bindu Rani, Junghwan Oh +7

3C 84 (NGC 1275) is the bright radio core of the Perseus Cluster. Even in the absence of strong relativistic effects, the source has been detected at Gamma-rays up to TeV energies.…

astro-ph.HE2021★ 24 cited

Search for neutrinos in coincidence with gravitational wave events from the LIGO-Virgo O3a Observing Run with the Super-Kamiokande detector

Kamiokande collaboration, K. Abe, C. Bronner +209

The Super-Kamiokande detector can be used to search for neutrinos in time coincidence with gravitational waves detected by the LIGO-Virgo Collaboration (LVC). Both low-energy ($7-1…

astro-ph.HE2021★ 22 cited

The jet collimation profile at high resolution in BL Lacertae

C. Casadio, N. R. MacDonald, B. Boccardi +14

Controversial studies on the jet collimation profile of BL Lacertae (BL Lac), the eponymous blazar of BL Lac objects class, complicate the scenario in this already puzzling class o…

astro-ph.HE2021★ 13 cited

GRB 191016A: A Long Gamma-Ray Burst Detected by TESS

Krista Lynne Smith, Ryan Ridden-Harper, Michael Fausnaugh +8

The TESS exoplanet-hunting mission detected the rising and decaying optical afterglow of GRB 191016A, a long Gamma-Ray Burst (GRB) detected by Swift-BAT but without prompt XRT or U…