Murchison Widefield Array and XMM-Newton observations of the Galactic supernova remnant G5.9+3.1

Abstract

Aims. In this paper we discuss the radio continuum and X-ray properties of the so-far poorly studied Galactic supernova remnant (SNR) G5.9+3.1. Methods. We present the radio spectral energy distribution (SED) of the Galactic SNR G5.9+3.1 obtained with the Murchison Widefield Array (MWA). Combining these new observations with the surveys at other radio continuum frequencies, we discuss the integrated radio continuum spectrum of this particular remnant. We have also analyzed an archival XMM-Newton observation, which represents the first detection of X-ray emission from this remnant. Results. The SNR SED is very well explained by a simple power-law relation. The synchrotron radio spectral index of G5.9+3.1 is estimated to be 0.42±0.03 and the integrated flux density at 1 GHz to be around 2.7 Jy. Furthermore, we propose that the identified point radio source, located centrally inside the SNR shell, is most probably a compact remnant of the supernova explosion. The shelllike X-ray morphology of G5.9+3.1 as revealed by XMM-Newton broadly matches the spatial distribution of the radio emission, where the radio-bright eastern and western rims are also readily detected in the X-ray while the radio-weak northern and southern rims are weak or absent in the X-ray. Extracted MOS1+MOS2+PN spectra from the whole SNR as well as the north, east, and west rims of the SNR are fit successfully with an optically thin thermal plasma model in collisional ionization equilibrium with a column density N H ∼ 0.80 × 10 22 cm −2 and fitted temperatures spanning the range kT ∼ 0.14 − 0.23 keV for all of the regions. The derived electron number densities n e for the whole SNR and the rims are also roughly comparable (ranging from ∼ 0.20 f −1/2 cm −3 to ∼ 0.40 f −1/2 cm −3 , where f is the volume filling factor). We also estimate the swept-up mass of the X-ray emitting plasma associated with G5.9+3.1 to be ∼ 46 f −1/2 M ⊙ .

Science with the Murchison Widefield Array: Phase I results and Phase II opportunities

“…It is detecting this latter category of SNRs to which the MWA is well-suited, with its superb diffuse source sensitivity. As expected (Bowman et al 2013), the Phase I MWA proved itself to be a powerful machine for the detection of new SNRs (Hurley-Walker et al 2019a;Maxted et al 2019;Onić et al 2019), including several that had been previously misclassified as HII regions (Hindson et al 2016). These reclassifications were possible, thanks to the low-frequency coverage and the high-spectral resolution of the MWA: the spectra of H II regions turn over and go into absorption at the lowest part of the MWA band, and are thus readily distinguished from SNRs, which display power law spectra.…”

MeerKAT 1.3 GHz Observations of Supernova Remnants

“…The SNR G5.9+3.1 was listed in the catalog of new SNR candidates by Reich et al (1988). There were follow-up radio observations with the Murchison Widefield Array (Onić et al 2019), who published a spectral index of α = −0.42. The best to-date image is from this paper at 200 MHz and with a resolution of 2 4.…”