SNR G349.7+0.2: A γ-ray source in the far 3 kpc arm of the galactic center

Abstract

We analyze the H I absorption profile for TeV supernova remnant (SNR) G349.7+0.2 based on updated knowledge of the inner Galaxy's structure. We significantly revise its kinematic distance from the previous 22 kpc to 11.5 kpc, indicating it is in the far 3 kpc arm of the Galactic center. We give a revised age of 1800 yr for G349.7+0.2 which has a low explosion energy of 2.5 × 1050 erg. This removes G349.7+0.2 from the set of brightest SNRs in radio and X-ray to γ-ray wavebands and helps us to better understand γ-ray emission originating from this remnant. However, one needs to use caution when discussing old kinematic distances of Galactic objects (e.g., SNRs, pulsars, and H II regions) in the range of -12° ≤ l ≤ 12° with distance estimates of ≥5.5 kpc. © 2014. The American Astronomical Society. All rights reserved.