Iron line and diffuse hard X-ray emission from the starburst galaxy M82
| dc.creator | Strickland, D. K. | |
| dc.creator | Heckman, T. M. | |
| dc.date | 2006-11-28 | |
| dc.date.accessioned | 2026-07-07T12:31:13Z | |
| dc.date.available | 2026-07-07T12:31:13Z | |
| dc.description | We examine the properties of the diffuse hard X-ray emission in the classic starburst galaxy M82. We use new Chandra ACIS-S observations in combination with reprocessed archival Chandra ACIS-I and XMM-Newton observations. We find E~6.7 keV Fe He-alpha emission is present in the central |r| < 200 pc, |z| < 100 pc of M82 in all datasets at high statistical significance, in addition to a possibly non-thermal X-ray continuum and marginally significant E=6.4 keV Fe K-alpha line emission. No statistically significant Fe emission is found in the summed X-ray spectra of the point-like X-ray sources or the ULX in the two epochs of Chandra observation. The total nuclear region iron line fluxes in the 2004 April 21 XMM-Newton observation are consistent with those of the Chandra-derived diffuse component, but in the 2001 May 6 XMM-Newton observation they are significantly higher and also both E=6.4 and E=6.9 keV iron lines are detected. We attribute the excess iron line emission to the Ultra-Luminous X-ray source in its high state. In general the iron K-shell luminosity of M82 is dominated by the diffuse component. The total X-ray luminosity of the diffuse hard X-ray emission (corrected for emission by unresolved low luminosity compact objects) is L_X ~ 4.4 x 10^39 erg/s in the E=2-8 keV energy band, and the 6.7 keV iron line luminosity is L_X ~ (1.1 -- 1.7) x 10^38 erg/s. The 6.7 keV iron line luminosity is consistent with that expected from the previously unobserved metal-enriched merged supernova ejecta that is thought to drive the larger-scale galactic superwind. The iron line luminosity implies a thermal pressure within the starburst region of P/k ~ 2 x 10^7 K/cm^3, which is consistent with independent observational estimates of the starburst region pressure [Abstract abridged]. | |
| dc.description | Accepted for publication in the ApJ. 25 pages, 7 bitmapped figures (full resolution PDF available at http://proteus.pha.jhu.edu/~dks/dks_published.html) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0611859 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0611859 | |
| dc.identifier | Astrophys.J.658:258-281,2007 | |
| dc.identifier | doi:10.1086/511174 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/216376 | |
| dc.subject | Astrophysics | |
| dc.title | Iron line and diffuse hard X-ray emission from the starburst galaxy M82 | |
| dc.type | text |