A Possible Supernova Remnant high above the Galactic Disk

Abstract

We present the analysis of three Suzaku observations of a bright arc in the ROSAT All-Sky Survey 1/4 keV maps at $l \approx 247\degr$, $b \approx -64\degr$. In particular, we have tested the hypothesis that the arc is the edge of a bubble blown by an extraplanar supernova. One pointing direction is near the brightest part of the arc, one is toward the interior of the hypothesized bubble, and one is toward the bubble exterior. We fit spectral models generated from 1-D hydrodynamical simulations of extraplanar supernova remnants (SNRs) to the spectra. The spectra and the size of the arc ($\mathrm{radius} \approx 5\degr$) are reasonably well explained by a model in which the arc is the bright edge of a $\sim$100,000-yr old SNR located $\sim$1--2 kpc above the disk. The agreement between the model and the observations can be improved if the metallicity of the X-ray--emitting gas is $\sim$1/3 solar, which is plausible, as the dust which sequesters some metals is unlikely to have been destroyed in the lifetime of the SNR. The width of the arc is larger than that predicted by our SNR model; this discrepancy is also seen with the Vela SNR, and may be due to the 1-D nature of our simulations. If the arc is indeed the edge of an extraplanar SNR, this work supports the idea that extraplanar supernovae contribute to the heating of the $\sim$million-degree gas in the halo.

16 pages, 11 figures. Accepted for publication in the Astrophysical Journal

References in corpus (6)

• Charge-Transfer induced EUV and Soft X-ray emissions in the Heliosphere
• OVII and OVIII line emission in the diffuse soft X-ray background: heliospheric and galactic contributions
• Xmm-Newton Observations of the Diffuse X-ray Background
• Limits on Hot Galactic Halo Gas from X-ray Absorption Lines
• Determining The Galactic Halo's Emission Measure from UV and X-ray Observations
• A Study of the Vertical Motion of Supernova Remnant Bubbles in the Interstellar Medium Drawn from the Results of Three-Dimensional MHD Simulations

Cited by in corpus (3)

• The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations
• An XMM-Newton Survey of the Soft X-ray Background. I. The O VII and O VIII Lines Between l=120 and l=240
• Impact of supernova and cosmic-ray driving on the surface brightness of the galactic halo in soft X-rays