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Simultaneous X-ray (BeppoSAX, 0.1-300 keV) and radio (Ryle Telescope, 15 GHz) observations of the superluminal galactic source GRS 1915+105 in high flux state were carried out starting October 1996. Here we present the simultaneous…

Astrophysics · Physics 2007-05-23 M. Feroci , G. Matt , G. Pooley , E. Costa , M. Tavani , T. Belloni

We present a multi-wavelength study of the Flat Spectrum Radio Quasar PKS 1222+216, analyzing its long-term variability of radio data obtained in 2013-2020 from the iMOGABA, MOJAVE, and VLBA-BU-BLAZAR programs, along with $\gamma$-ray data…

High Energy Astrophysical Phenomena · Physics 2026-03-12 Yeji Jo , Sang-Sung Lee

A model is developed for the time dependent electromagnetic - radio to gamma-ray - emission of active galactic nuclei, specifically, the blazars, based on the acceleration and creation of leptons at a propagating discontinuity or {\it…

Astrophysics · Physics 2008-02-03 M. M. Romanova , R. V. E. Lovelace

We perform the most detailed analysis to date of the X-ray state of the Galactic black hole candidate GRS 1915+105 just prior to (0 to 4 hours) and during the brief (1 to 7 hour) ejection of major (superluminal) radio flares. A very strong…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Brian Punsly , Jerome Rodriguez

We report imaging photometry of the radio-jet black hole candidate source GRS 1915+105 in the infrared K band. The observations reveal rapid infrared flare events on timescales of less than an hour. These events are strikingly similar to…

Astrophysics · Physics 2016-01-13 R. P. Fender , G. G. Pooley , C. Brocksopp , S. J. Newell

We present the $\gamma$-ray observations of the flat-spectrum radio quasar PKS 1441+25 (z=0.939), using the {\it Fermi} large Area Telescope data accumulated during January - December 2015. A $\gamma$-ray flare was observed in January 24,…

High Energy Astrophysical Phenomena · Physics 2017-07-26 N. Sahakyan , S. Gasparyan

In this article, models are constructed of the compact jet in GRS 1915+105 during an epoch of optimal data capture. On April 02, 2003, the object was observed in the hard X-ray/soft gamma ray band (INTEGRAL), hard X-ray band (RXTE), near IR…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Brian Punsly

(abridged) This is the second paper presenting the results of two years of monitoring of GRS 1915+105 with \integral and \rxte and the Ryle Telescope. We present the X-ray spectral and temporal analysis of four observations which showed…

We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Telescope mission. While investigating the previously reported…

We analysed the long-term variability of four microquasars (GRS 1915+105, Cyg X-1, Cyg X-3, and Sco X-1) in radio and X rays. The results of our analysis indicate the existence of two distinct modes of energy output, which we refer to as…

Astrophysics · Physics 2008-11-26 Carlo Nipoti , Katherine M. Blundell , James Binney

Since its discovery in 1992, GRS 1915+105 has been among the brightest sources in the X-ray sky. However, in early 2018, it dimmed significantly and has stayed in this faint state ever since. We report on AstroSat and NuSTAR observation of…

High Energy Astrophysical Phenomena · Physics 2024-02-12 Sajad Boked , Bari Maqbool , V. Jithesh , Ranjeev Misra , Naseer Iqbal , Yashpal Bhulla

(abridged) Two XMM-Newton observations of the black-hole binary GRS1915+105 were triggered in 2004, during a long "plateau" state of the source. (...) While the light curves show just small amplitude variations (a few percent) at timescales…

Two XMM-Newton observations of the black-hole binary GRS1915+105 were triggered in 2004 (April 17 and 21), during a long "plateau" state of the source. We analyzed the data collected with EPIC-pn in Timing and Burst modes, respectively. No…

We report on the first high frequency VLBI observations of the nearby broad absorption line quasar (BALQSO), Mrk 231. Three epochs of observations were achieved at 15 GHz and 22 GHz, two of these included 43 GHz observations as well. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Cormac Reynolds , Brian Punsly , Preeti Kharb , Christopher P. O'Dea , Joan Wrobel

We present time resolved X-ray spectroscopy of the microquasar GRS1915+105 with the MAXI observatory in order to study the accretion state just before and during the ejections associated with its major flares. Radio monitoring with the…

Astrophysics of Galaxies · Physics 2014-03-05 Brian Punsly , Jerome Rodriguez , Sergei A. Trushkin

H.E.S.S. observed TeV blazar PKS 2155--304 in a strong flare state in 2006 July. The TeV flux varied on timescale as short as a few minutes, which sets strong constraints on the properties of the emission region. By use of the synchrotron…

Astrophysics · Physics 2009-11-13 M. Kusunose , F. Takahara

Context. The repeating FRB121102 is so far the only extra-galactic Fast Radio Burst found to be associated with a counterpart, a steady radio source with a nearly flat spectral energy distribution (SED) in centimeter wavelengths. Aims.…

High Energy Astrophysical Phenomena · Physics 2021-12-01 L Resmi , J Vink , C H Ishwara-Chandra

We report on the timing analysis of RXTE observations of the Galactic micro-quasar GRS 1915+105 performed in 2003. Out of a total of six times ~20 ks, we focus here only on the three observations during which GRS 1915+105 is found in a…

Astrophysics · Physics 2009-11-10 J. Rodriguez , S. Corbel , D. C. Hannikainen , T. Belloni , A. Paizis , O. Vilhu

This study analyzes the multi-wavelength flaring activity of the distant flat spectrum radio quasar (FSRQ) OP 313 (z=0.997) during November 2023 to March 2024, using data from Fermi-Large Area Telescope, Swift X-ray Telescope, and…

High Energy Astrophysical Phenomena · Physics 2025-02-05 P N Naseef Mohammed , T. Aminabi , C. Baheeja , Vaidehi S. Paliya , S Sahayanathan , C D Ravikumar

In the present work we consider energy accumulation mechanism in relativistic electron-positron plasma in the magnetosphere of pulsars. Waves propagating almost across the magnetic field lines are generated that accumulate the energy of…

High Energy Astrophysical Phenomena · Physics 2019-03-20 George Machabeli , Nino Chkheidze , Igor Malov