Kinematic distance study of the planetary nebulae-supernova remnant-HII region complex at G35.6-0.5

TL;DR

This study uses HI absorption spectra to determine the distances of various objects in the G35.6-0.5 complex, revising the supernova remnant's distance and exploring its associations with other astronomical sources.

Contribution

The paper provides revised kinematic distances for objects in the G35.6-0.5 complex, including a significantly closer estimate for the supernova remnant, based on HI absorption analysis.

Findings

SNR G35.6-0.4 is at approximately 3.6 kpc, closer than previous estimates.

The revised distances support an association between the SNR and the molecular cloud linked to HESS J1858+020.

SNR G35.6-0.4 is unlikely associated with PSR J1857+0210 or PSR J1857+0212.

Abstract

Two possible planetary nebulae (PN G035.5-00.4 and IRAS 18551+0159), one newly re-identified supernova remnant (SNR G35.6-0.4), and one HII region (G35.6-0.5) form a line-of-sight-overlapped complex known as G35.6-0.5. We analyze 21 cm HI absorption spectra towards the complex to constrain their kinematic distances. PN G035.5-00.4 has a distance from 3.8+/-0.4 kpc to 5.4+/-0.7 kpc. IRAS 18551+0159 is at 4.3+/-0.5 kpc. We discuss the distance for SNR 35.6-0.4, for which the previous estimate was 10.5 kpc, and find plausible for it to be 3.6+/-0.4 kpc. The new distance of SNR G35.6-0.4 and the derived mass for the ~55 km/s CO molecular cloud can accommodate an association with HESS J1858+020. We also conclude that SNR G35.6-0.4 is unlikely associated with PSR J1857+0210 or PSR J1857+0212, which are projected into the SNR area.