High-resolution Near-infrared Spectroscopic Study of Galactic Supernova Remnants. I. Kinematic Distances

Abstract

We have carried out high-resolution near-infrared spectroscopic observations toward 16 Galactic supernova remnants (SNRs) showing strong H${}_2$ emission features. A dozen bright H${}_2$ emission lines are clearly detected for individual SNRs, and we have measured their central velocities, line widths, and fluxes. For all SNRs except one (G9.9$-$0.8), the H${}_2$ line ratios are well consistent with that of thermal excitation at $T\sim 2000$ K, indicating that the H${}_2$ emission lines are most likely from shock-excited gas and therefore that they are physically associated with the remnants. The kinematic distances to the 15 SNRs are derived from the central velocities of the H${}_2$ lines using a Galactic rotation model. We derive for the first time the kinematic distances to four SNRs: G13.5$+$0.2, G16.0$-$0.5, G32.1$-$0.9, and G33.2$-$0.6. Among the remaining 11 SNRs, the central velocities of the H${}_2$ emission lines for six SNRs are well consistent ($\pm 5$ km s${}^{-1}$) with those obtained in previous radio observations, while for the other five SNRs (G18.1$-$0.1, G18.9$-$1.1, Kes 69, 3C 396, W49B) they are significantly different. We discuss the velocity discrepancies in these five SNRs. In G9.9$-$0.8, the H${}_2$ emission shows nonthermal line ratios and narrow line width ($\sim 4$ km s${}^{-1}$), and we discuss its origin.

50 pages, 15 figures, 2 tables; accepted in AJ on 2020 Oct. 9

References in corpus (9)

• The VLA Galactic Plane Survey
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) I: Project Overview and Initial Results
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• A Survey of Hydroxyl Toward Supernova Remnants: Evidence for Extended 1720 MHz Maser Emission
• The Distances of SNRs Kes 69 and G21.5-0.9 from HI and 13CO Spectra
• Updated radio $\Sigma -D$ relation for Galactic supernova remnants
• [Fe II] and H2 filaments in the Supernova Remnant G11.2-0.3: Supernova Ejecta and Presupernova Circumstellar Wind
• Supernova remnant W49B and its environment
• Near-infrared [Fe II] and H${}_2$ Emission-line Study of Galactic Supernova Remnants in the First Quadrant

Cited by in corpus (13)

• Classifying Unidentified X-ray Sources in the Chandra Source Catalog Using a Multiwavelength Machine-learning Approach
• ALMA CO Observations of the Mixed-Morphology Supernova Remnant W49B: Efficient Production of Recombining Plasma and Hadronic Gamma-rays via Shock-Cloud Interactions
• Thermal radio absorption as a tracer of the interaction of SNRs with their environments
• Unusually high HCO+/CO ratios in and outside supernova remnant W49B
• Atlas of CO-Line Shells and Cavities around Galactic Supernova Remnants with FUGIN
• TRAPUM search for pulsars in supernova remnants and pulsar wind nebulae -- I. Survey description and initial discoveries
• QUIJOTE scientific results -- V. The microwave intensity and polarisation spectra of the Galactic regions W49, W51 and IC443
• Polarized Emission From Four Supernova Remnants In The THOR Survey
• The main jet axis of the W49B supernova remnant
• Interaction between the Supernova Remnant W44 and the Infrared Dark Cloud G034.77-00.55: shock induced star formation?
• Supernova Shocks in Molecular Clouds: Shocks Driven into Dense Cores in IC 443 and 3C 391
• Chemical complexity in star formation induced by stellar feedback: cores shock-formed by the supernova remnant W44
• Broadband radio study of the supernova remnant Kes 73