The Accretion Flow - Discrete Ejection Connection in GRS 1915+105

Abstract

The microquasar GRS~1915+105 is known for its spectacular discrete ejections. They occur unexpectedly, thus their inception escapes direct observation. It has been shown that the X-ray flux increases in the hours leading up to a major ejection. In this article, we consider the serendipitous interferometric monitoring of a modest version of a discrete ejection described in Reid et al. (2014) that would have otherwise escaped detection in daily radio light curves. The observation begins $\sim 1$ hour after the onset of the ejection, providing unprecedented accuracy on the estimate of the ejection time. The astrometric measurements allow us to determine the time of ejection as $\mathrm{MJD}56436.274_{-0.013}^{+0.016}$, i.e., within a precision of 41 minutes (95\% confidence). Just like larger flares, we find that the X-ray luminosity increases in last 2 - 4 hours preceding ejection. Our finite temporal resolution indicates that this elevated X-ray flux persists within $21.8_{-19.1}^{+22.6}$ minutes of the ejection with 95\% confidence, the highest temporal precision of the X-ray - superluminal ejection connection to date. This observation provides direct evidence that the physics that launches major flares occurs on smaller scales as well (lower radio flux and shorter ejection episodes). The observation of a X-ray spike prior to a discrete ejection, although of very modest amplitude suggests that the process linking accretion behavior to ejection is general from the smallest scales to high luminosity major superluminal flares.

To appear in ApJ

References in corpus (8)

• A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass
• Two Years of INTEGRAL monitoring of GRS 1915+105 Part 2: X-Ray Spectro-Temporal Analysis
• Two years of INTEGRAL monitoring of GRS 1915+105 Part 1: multiwavelength coverage with INTEGRAL, RXTE, and the Ryle radio Telescope
• A Temporal Analysis Indicates a Mildly Relativistic Compact Jet in GRS~1915+105
• The Relationship Between X-ray Luminosity and Major Flare Launching in GRS 1915+105
• GRS 1915+105 as a Galactic Analog of a Fanaroff-Riley II Quasar
• Calibrated Estimates of the Energy in Major Flares of GRS 1915+105
• Evidence of Elevated X-Ray Absorption Before and During Major Flare Ejections in GRS 1915+105

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