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Title: Evidence of elevated X-ray absorption before and during major flare ejections in GRS 1915+105

We present time-resolved X-ray spectroscopy of the microquasar GRS 1915+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 RATAN-600 radio telescope from 4.8-11.2 GHz has revealed two large, steep-spectrum major flares in the first eight months of 2013. Since the RATAN has received one measurement per day, we cannot determine the jet-forming time without more information. Fortunately, this is possible since a distinct X-ray light curve signature that occurs preceding and during major ejections has been determined in an earlier study. The X-ray luminosity spikes to very high levels in the hours before ejection, then becomes variable (with a nearly equal X-ray luminosity when averaged over the duration of the ejection) during a brief 3-8 hr ejection process. By comparing this X-ray behavior with MAXI light curves, we can estimate the beginning and end of the ejection episode of the strong 2013 flares to within ∼3 hr. Using this estimate in conjunction with time-resolved spectroscopy from the data in the MAXI archives allows us to deduce that the X-ray absorbing hydrogen column density increases significantly in the hours preceding the ejections andmore » remains elevated during the ejections responsible for the major flares. This finding is consistent with an outflowing wind or enhanced accretion at high latitudes.« less
Authors:
 [1] ;  [2] ;  [3]
  1. 1415 Granvia Altamira, Palos Verdes Estates, CA 90274 (United States)
  2. Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU SAp, F-91191 Gif-sur-Yvette (France)
  3. Special Astrophysical Observatory RAS, Nizhnij Arkhyz, 369167 (Russian Federation)
Publication Date:
OSTI Identifier:
22351554
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; BLACK HOLES; DENSITY; GALAXIES; HYDROGEN; LUMINOSITY; MAGNETOHYDRODYNAMICS; QUASARS; RADIO TELESCOPES; SPECTRA; STARS; TIME RESOLUTION; VISIBLE RADIATION; X RADIATION; X-RAY SPECTROSCOPY