X-Ray Spectral Analysis of the Steady States of GRS1915+105
Abstract
We report on the X-ray spectral behavior within the steady states of GRS1915+105. Our work is based on the full data set of the source obtained using the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) and 15 GHz radio data obtained using the Ryle Telescope. The steady observations within the X-ray data set naturally separated into two regions in the color-color diagram and we refer to these regions as steady-soft and steady-hard. GRS1915+105 displays significant curvature in the coronal component in both the soft and hard data within the RXTE/PCA bandpass. A majority of the steady-soft observations displays a roughly constant inner disk radius ({R}{{in}}), while the steady-hard observations display an evolving disk truncation which is correlated to the mass accretion rate through the disk. The disk flux and coronal flux are strongly correlated in steady-hard observations and very weakly correlated in the steady-soft observations. Within the steady-hard observations, we observe two particular circumstances when there are correlations between the coronal X-ray flux and the radio flux with log slopes η ∼ 0.68+/- 0.35 and η ∼ 1.12+/- 0.13. They are consistent with the upper and lower tracks of Gallo et al. (2012), respectively. A comparison of the model parameters to the state definitions shows that almost all of the steady-soft observations match the criteria of either a thermal or steep power-law state, while a large portion of the steady-hard observations match the hard-state criteria when the disk fraction constraint is neglected.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2016
- DOI:
- 10.3847/0004-637X/822/2/60
- arXiv:
- arXiv:1509.08941
- Bibcode:
- 2016ApJ...822...60P
- Keywords:
-
- accretion;
- accretion disks;
- binaries: close;
- black hole physics;
- magnetic fields;
- X-rays: binaries;
- X-rays: individual: GRS1915+105;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 21 pages, 15 figures, 2 tables. Accepted for publication in ApJ