A Comparison of Ultraluminous X-ray Sources in NGC 1399 and the Antennae Galaxies (NGC 4038/4039)
| dc.creator | Feng, Hua | |
| dc.creator | Kaaret, Philip | |
| dc.date | 2006-08-01 | |
| dc.date.accessioned | 2026-07-07T10:39:41Z | |
| dc.date.available | 2026-07-07T10:39:41Z | |
| dc.description | The temporal and spectral properties of ultraluminous X-ray sources (ULXs, L>2x10^39 ergs/s) and bright X-ray sources (L>3x10^38 ergs/s) are examined and compared in two extremely different host environments: the old elliptical galaxy NGC 1399 and the young, starforming Antennae galaxies (NGC 4038/4039). ULXs in NGC 1399 show little variability on either long or short time scales. Only 1 of 8 ULXs and 10 of 63 bright sources in NGC 1399 are variable at a confidence level of 90%. On long timescales, the NGC 1399 sources are steadier than most Galactic black hole X-ray binaries, but similar to GRS 1915+105. The outburst duration of the NGC 1399 sources is about 20 yrs, again, similar to that of GRS 1915+105. The bright X-ray sources in NGC 1399 may be black hole X-ray binaries with giant star companions similar to GRS 1915+105. The brightest ULX (PSX-1) in NGC 1399 is coincident with a globular cluster, shows a hard spectrum with a photon index around 1.5, and has a nearly constant luminosity around 5x10^39 erg/s. It may be an intermediate-mass black hole (IMBH) in a hard spectral state. In contrast to NGC 1399, the ULXs in the Antennae are all variable and a large fraction of the bright sources (9 of 15) are also variable. The variability and luminosity of ULXs in the Antennae suggest they are black hole high mass X-ray binaries accreting via Roche-lobe overflow. A flare with a duration of about 5 ks is found from Antennae X-42. The most luminous ULX, X-16, with a very hard spectrum (Gamma=1.0~1.3) and a luminosity which varies by a factor of 10, could be an IMBH candidate. | |
| dc.description | 10 pages, 9 figures, accepted for publication in ApJ | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0608024 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0608024 | |
| dc.identifier | Astrophys.J.653:536-544,2006 | |
| dc.identifier | doi:10.1086/508141 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/181116 | |
| dc.subject | Astrophysics | |
| dc.title | A Comparison of Ultraluminous X-ray Sources in NGC 1399 and the Antennae Galaxies (NGC 4038/4039) | |
| dc.type | text |