Infrared and millimeter observations of the galactic superluminal source GRS 1915+105

TL;DR

This paper presents millimeter and infrared observations of GRS 1915+105, establishing its distance, luminosity, and variability, and comparing it to SS 433 to suggest a similar binary system with a compact object and accretion disk.

Contribution

It provides the first detailed infrared and millimeter observational analysis of GRS 1915+105, estimating its distance, luminosity, and variability, and drawing parallels with SS 433.

Findings

Distance estimated at 12.5 kpc from the Sun.

Infrared variability of nearly 2 magnitudes over time.

Similarity to SS 433 indicating a binary system with a compact object.

Abstract

Millimeter observations of the galactic source of relativistic ejections GRS 1915+105 (Mirabel & Rodriguez 1994) are consistent with this source being at a kinematic distance D = 12.5 +/- 1.5 kpc from the Sun, behind the core of a molecular cloud at 9.4 +/- 0.2 kpc. At this distance, GRS 1915+105, frequently radiating nearly 3 x 10^{38} erg/s in the X-rays, becomes the most luminous X-ray source in the Galaxy. The total hydrogen column density Nh = 4.7 +/- 0.2 x 10^{22} cm-2 along the line of sight corresponds to a visual absorption Av = 26.5 +/- 1 magnitude. The infrared counterpart of GRS 1915+105 exhibits in the 1.2 micrometre - 2.2 micrometre band variations of nearly 1 magnitude in a few hours and of nearly 2 magnitudes over longer intervals of time. In the infrared, GRS 1915+105 is strikingly similar to SS 433, and unlike any other known stellar source in the Galaxy. The infrared resemblance in absolute magnitude, color, and time variability, between these two sources of relativistic ejections suggests that GRS 1915+105, as SS 433, consists of a collapsed object (neutron star or black hole) with a thick accretion disk in a high-mass-luminous binary system.