Jet-ISM Interactions near the Microquasars GRS 1758-258 and 1E 1740.7-2942

TL;DR

This study uses ALMA observations to identify molecular structures indicating jet-ISM interactions near two microquasars, estimating jet power and confirming their location in the Galactic center through astro-chemistry.

Contribution

First detailed molecular analysis of jet-ISM interactions near GRS 1758-258 and 1E 1740.7-2942, estimating jet power and confirming their Galactic center location.

Findings

Detection of molecular lines indicating jet-driven cavities.

Estimated jet power ranges for both systems.

Confirmed location within the Galactic center molecular zone.

Abstract

We present Atacama Large Millimeter/Sub-millimeter Array observations of the candidate jet-ISM interaction zones near the black hole X-ray binaries GRS 1758$-$258 and 1E 1740.7$-$2942. Using these data, we map the molecular line emission in the regions, detecting emission from the HCN [$J=1-0$], HCO$^+$ [$J=1-0$], SiO [$J=2-1$], CS [$J=2-1$], $^{13}$CO [$J=1-0$], C$^{18}$O [$J=1-0$], HNCO [$J=4_{0,4}-3_{0,3}$], HNCO [$J=5_{0,5}-4_{0,4}$], and CH$_3$OH [$J=2_{1,1}-1_{1,0}$] molecular transitions. Through examining the morphological, spectral, and kinematic properties of this emission, we identify molecular structures that may trace jet-driven cavities in the gas surrounding these systems. Our results from the GRS 1758$-$258 region in particular, are consistent with recent work, which postulated the presence of a jet-blown cocoon structure in deep radio continuum maps of the region. Using these newly discovered molecular structures as calorimeters, we estimate the time averaged jet power from these systems, finding $(1.1-5.7)\times10^{36}{\rm erg\,s}^{-1}$ over $0.12-0.31$ Myr for GRS 1758$-$258 and $(0.7-3.5)\times10^{37}{\rm erg\,s}^{-1}$ over $0.10-0.26$ Myr for 1E 1740.7$-$2942. Additionally, the spectral line characteristics of the detected emission place these molecular structures in the central molecular zone of our Galaxy, thereby constraining the distances to the black hole X-ray binaries to be $8.0\pm1.0$ kpc. Overall, our analysis solidifies the diagnostic capacity of molecular lines, and highlights how astro-chemistry can both identify jet-ISM interaction zones and probe jet feedback from Galactic X-ray binaries.