X-ray supernova remnants in the starburst region of M82

Abstract

We searched for X-ray supernova remnants (SNRs) in the starburst region of M82, using archival data from the Chandra X-ray Observatory with a total effective exposure time of 620 ks with an X-ray spectroscopic selection. Strong line-emission from Fe xxv at 6.7 keV is a characteristic spectral feature of hot, shocked gas of young SNRs and distinctive among the discrete sources in the region populated by X-ray binaries. We selected candidates using narrow-band imaging aimed at the line excess and identified six (and possibly a seventh) X-ray SNRs. Two previously known examples were recovered by our selection. Five of them have radio counterparts, including the radio supernova SN2008iz, which was discovered as a radio transient in 2008. It shows a hard X-ray spectrum with a blueshifted Fe K feature with v ~ -2700 km/s, both of which suggest its youth. The 4-8 keV luminosities of the selected SNRs are in the range of (0.3-3)e38 erg/s. We made a crude estimate of the supernova rate, assuming that more luminous SNRs are younger, and found 0.06 (0.03-0.13) /yr, in agreement with the supernova rates estimated by radio observations and the generally believed star formation rate of M82, although the validity of the assumption is questionable. A sum of the Fe xxv luminosity originating from the selected X-ray SNRs consists of half of the total Fe xxv luminosity observed in the central region of M82. We briefly discuss its implications for starburst winds and the Fe xxv emission in more luminous starburst galaxies.

Accepted for publication in A&A, 13 pages, 10 figures

References in corpus (13)

• The Youngest Galactic Supernova Remnant: G1.9+0.3
• Iron line and diffuse hard X-ray emission from the starburst galaxy M82
• Deep MERLIN 5GHz Radio Imaging of Supernova Remnants in the M82 Starburst
• High-ionization Fe K emission from luminous infrared galaxies
• An Obscured, Seyfert-2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk Winds
• Spatially resolved Fe K spectroscopy of NGC 4945
• A ~60-day super-orbital period originating from the ultraluminous X-ray pulsar in M82
• 15 years of VLBI observations of two compact radio sources in Messier 82
• Discovery of a bright radio transient in M82: a new radio supernova?
• The Ultraluminous X-ray Sources near the Center of M82
• Evolution of the progenitors of SNe 1993J and 2011dh revealed through late time radio and X-ray studies
• The radio evolution of supernova SN2008iz in M82
• The Exceptional X-ray Evolution of SN1996cr in High Resolution

Cited by in corpus (3)

• Origin of the diffuse 4-8 keV emission in M82
• A Fast, Hot Wind from a Nuclear Starburst
• Non-thermal emission in the central starburst region of M82