Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2010-03-22
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
4 pages, accepted for ApJ Letters
Scientific paper
We present Hubble Space Telescope observations in the far UV of the ultraluminous X-ray source in NGC 6946 associated with the optical nebula MF 16. Both a point-like source coincident with the X-ray source and the surrounding nebula are detected in the FUV. The point source has a flux of 5E-16 erg s^-1 cm^-2 Ang^-1 and the nebula has a flux of 1.6E-15 erg s^-1 cm^-2 Ang^-1, quoted at 1533 Ang and assuming an extinction of A_V = 1.54. Thus, MF 16 appears to host the first directly detected ultraluminous UV source (ULUV). The flux of the point-like source is consistent with a blackbody with T ~ 30,000 K, possibly from a massive companion star, but this spectrum does not create sufficient ionizing radiation to produce the nebular HeII flux and a second, hotter emission component would be required. A multicolor disk blackbody spectrum truncated with an outer disk temperature of ~16,000 K provides an adequate fit to the FUV, B, V, I, and HeII fluxes and can produce the needed ionizing radiation. Additional observations are required to determine the physical nature of the source.
Feng Hua
Kaaret Philip
Tao Lian
Wong Diane Sonya
No associations
LandOfFree
Direct Detection of an Ultraluminous Ultraviolet Source does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Direct Detection of an Ultraluminous Ultraviolet Source, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct Detection of an Ultraluminous Ultraviolet Source will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-207173