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We systematically investigate the variability of polarized X-rays on a timescale of a few seconds in the low/hard state of the black hole binary Cygnus X-1. The correlation between polarization degrees and angles with X-Ray intensity was…

High Energy Astrophysical Phenomena · Physics 2024-08-08 Kaito Ninoyu , Yuusuke Uchida , Shinya Yamada , Takayoshi Kohmura , Taichi Igarashi , Ryota Hayakawa , Tenyo Kawamura

The polarization position angles (PPA) of time samples with high linear polarization often show two parallel tracks across the pulsar profile that follow the rotating vector model (RVM). This feature support coherent curvature radiation…

High Energy Astrophysical Phenomena · Physics 2024-08-22 Dipanjan Mitra , Rahul Basu , George I. Melikidze

We report on a nine-month monitoring campaign of the blazar PG 1553+113, relying on three observations carried out in 2025 with the Imaging X-ray Polarimetry Explorer (IXPE) and supported by multi-wavelength facilities. The source displayed…

High Energy Astrophysical Phenomena · Physics 2026-05-14 Riccardo Middei , Svetlana G. Jorstad , Alan P. Marscher , Ioannis Liodakis , Matteo Perri , Alessandro Maselli , Stefano Ciprini , Emanuele Nardini , Simonetta Puccetti , Laura Di Gesu , Iván Agudo , Dawoon E. Kim , Ioannis Myserlis , A. Trindade Falcão , D. Ł. Król , Lucio A. Antonelli , Tommaso Aniello , Pouya M. Kouch , Kari Nilsson , Elina Lindfors , Tapio Pursimo , Francisco José Aceituno , Víctor Casanova , Gabriel Emery , Juan Escudero Pedrosa , Jorge Otero-Santos , Alfredo Sota , Vilppu Piirola , George A. Borman , Tatiana S. Grishina , Vladimir A. Hagen-Thorn , Evgenia N. Kopatskaya , Elena G. Larionova , Daria A. Morozova , Sergey S. Savchenko , Ekaterina V. Shishkina , Ivan S. Troitskiy , Yulia V. Troitskaya , Andrey A. Vasilyev , Alexey V. Zhovtan , Petra Benke , Lena Debbrecht , Julia Eich , Florian Eppel , Andrea Gokus , Steven Hämmerich , Jonas Heßdörfer , Matthias Kadler , Dana Kirchner , Georgios F. Paraschos , Florian Rösch , Wladislaw Schulga , Mark Gurwell , Garrett Keating , Ramprasad Rao , Emmanouil Angelakis , Alexander Kraus , Beatriz Agís-González , Dmitry Blinov , Anastasia Glykopoulou , Sara Capecchiacci , Alberto Floris , Panagiotis Fotis , Alkmini Koukoutsi , John A. Kypriotakis , Dimitrios A. Langis , Dimitrios Rompogiannakis , Aristeidis Polychronakis , Vasiliki Tsioupli , Stavros Vogiatzis , Orestis Zoumpoulakis , Sumie Tochihara , Ryo Imazawa , Mahito Sasada , Yasushi Fukazawa , Koji S. Kawabata , Makoto Uemura , Tsunefumi Mizuno , Tatsuya Nakaoka , Hiroshi Akitaya , Takahiro Akai

We report on the first results of the POLAMI program, a simultaneous 3.5 and 1.3mm full-Stokes-polarisation monitoring of a sample of 36 of the brightest active galactic nuclei in the northern sky with the IRAM 30m Telescope. Through a…

Astrophysics of Galaxies · Physics 2017-09-27 Ivan Agudo , Clemens Thum , Venkatessh Ramakrishnan , Sol N. Molina , Carolina Casadio , Jose L. Gomez

We report on a densely time sampled polarimetric flux density monitoring of the BL Lac object S5 0716+71 at 86 GHz and 229 GHz with the IRAM 30 m telescope within a coordinated broad spectral band campaign, centred around an INTEGRAL…

We present simultaneous UBV polarimetric and photometric observations of the pre-main-sequence binary AK Sco, obtained over 12 nights, slightly less than the orbital period of 13.6 days. The polarization is a sum of interstellar and…

Astrophysics · Physics 2009-11-10 N. Manset , P. Bastien , C. Bertout

For more than a decade from the late 1980s to the late 1990s, the intraday variable (IDV) quasar 0917+624 was known to be strongly variable with amplitude variations of 10-20% within 0.8 to 1.6 days. During that period it showed faster…

Astrophysics · Physics 2011-11-09 S. Bernhart , T. P. Krichbaum , L. Fuhrmann , A. Kraus

Qiao and his collaborators recently proposed an inverse Compton Scattering (ICS) model to explain radio emission of pulsars. In this paper, we investigate the polarization properties of pulsar emission in the model. First of all, using the…

Astrophysics · Physics 2009-10-31 R. X. Xu , J. F. Liu , J. L. Han , G. J. Qiao

Analysis of rapid variability at 4.85 GHz for the BL BLac object 0925+504 is presented and discussed. The structure functions (SF) are investigated with both refractive and weak interstellar scintillation (RISS/WISS) models analytically.…

Astrophysics of Galaxies · Physics 2018-04-26 Jun Liu , Xiang Liu

V CVn is a semiregular variable star with a V-band amplitude of $\approx2$ mag. This star has an unusually high amplitude of polarimetric variability: up to 6 per cent. It also exhibits a prominent inverse correlation between the flux and…

Solar and Stellar Astrophysics · Physics 2019-10-09 Boris Safonov , Sergei Lamzin , Alexandr Dodin , Alexey Rastorguev

Mean pulse profiles and polarization properties are presented for nine southern pulsars. The observations were made using the Parkes radio telescope at frequencies near 1330 MHz; three of the nine pulsars were also observed at 660 MHz. A…

Astrophysics · Physics 2009-11-10 R N Manchester , J L Han

Fast radio bursts (FRBs) are transient radio bursts of extragalactic origin characterized by millisecond durations and high luminosities. We report on observations of FRB 20240114A conducted with the Robert C. Byrd Green Bank Telescope…

Although it is well-established that some extragalactic radio sources are time-variable, the properties of this radio variability, and its connection with host galaxy properties, remain to be explored---particularly for faint sources. Here…

The quasar 1156+295 (4C +29.45) is one of the targets in the Urumqi monitoring program which aimed to search for evidence of annual modulation in the timescales of intra-day variable (IDV) sources. The IDV observations of 1156+295 were…

High Energy Astrophysical Phenomena · Physics 2013-07-04 B. -R. Liu , X. Liu , N. Marchili , J. Liu , L. -G. Mi , T. P. Krichbaum , L. Fuhrmann , J. A. Zensus

Polarization from active galactic nuclei is interpreted as a signpost of the role of magnetic fields in the launch and collimation of their relativistic radio jets. Here, we report the detection of a clear polarization signal from ALMA…

Astrophysics of Galaxies · Physics 2018-12-26 I. Marti-Vidal , S. Muller

Fast radio bursts (FRBs) are extra-galactic sources with unknown physical mechanisms. They emit millisecond-duration radio pulses with isotropic equivalent energy of $10^{36}\sim10^{41}$ ergs. This corresponds to a brightness temperature of…

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 Transiting Exoplanet Survey Satellite (TESS) and by the Whole…

High Energy Astrophysical Phenomena · Physics 2021-05-12 C. M. Raiteri , M. Villata , V. M. Larionov , S. G. Jorstad , A. P. Marscher , Z. R. Weaver

We study the hard X-ray (20-100 keV) variability of the Galactic Center (GC) and of the nearby sources on the time scale of 1000 s. We find that 3 of the 6 hard X-ray sources detected by INTEGRAL within the central 1 degree of the Galaxy…

Astrophysics · Physics 2007-05-23 A. Neronov , M. Chernyakova , T. J. -L. Courvoisier , R. Walter

The supermassive black hole Sagittarius A* (Sgr A*) exhibits temporal and spectral variability across the electromagnetic spectrum. However, variability at radio frequencies below ~ 5 GHz for timescales shorter than a day remains largely…

We study the high-energy emission of the Galactic black hole candidate GX 339-4 using INTEGRAL/SPI and simultaneous RXTE/PCA data. By the end of January 2007, when it reached its peak luminosity in hard X-rays, the source was in a bright…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Robert Droulans , Renaud Belmont , Julien Malzac , Elisabeth Jourdain