Jet-ISM interactions near the microquasars GRS 1758-258 and 1E 1740.7-2942

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], 13CO [J = 1-0], C18O [J = 1-0], HNCO [J = 40,4-30,3], HNCO [J = 50,5-40,4], and CH3OH [J = 21,1-11,0] 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) × 1036 erg s-1 over 0.12-0.31 Myr for GRS 1758-258 and (0.7-3.5) × 1037 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 ± 1.0 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.