Cygnus X-3: Its Little Friend's Counterpart, the Distance to Cygnus X-3, and Outflows/Jets

TL;DR

This study uses submillimeter observations to determine the distance to Cygnus X-3 via its associated Bok globule, revealing active star formation and bipolar outflows in the Little Friend, refining the system's distance estimate.

Contribution

It provides the first molecular emission detection from the Little Friend and estimates Cygnus X-3's distance using Bayesian kinematic models, highlighting active star formation.

Findings

Detected molecular emission from the Little Friend in CO lines.

Estimated Cygnus X-3's distance as approximately 7.4 kpc.

Discovered bipolar molecular outflows indicating star formation.

Abstract

Chandra observations have revealed a feature,within 16" of Cygnus X-3 which varied in phase with Cygnus X-3. This feature was shown to be a Bok globule which is along the line of sight to Cygnus X-3. We report on observations made with Submillimeter Array (SMA) to search for molecular emission from this globule, also known as Cygnus X-3's "Little Friend" (LF). We have found a counterpart in both 12CO (2-1) and 13}CO (2-1) emission. From the velocity shift of the molecular lines, we are able to find two probable distances based on the Bayesian model of Milky Way kinematics of Reid et al. 2016. For the LF velocity of -47.5 km/s, we get a distance of 6.1 +/- 0.6 kpc (62% probability) and 7.8 +/- 0.6 ~kpc (38% probability). This yields a distance to Cyg X-3 of 7.4 +/- 1.1 kpc and 10.2 +/-1.2 ~kpc, respectively. Based on the probabilities entailed, we take 7.4 +/- 1.1 kpc as the preferred distance to Cyg X-3. We also report the discovery of bipolar molecular outflow, suggesting that there is active star formation occurring within the Little Friend.