SPITZER OBSERVATIONS OF MF 16 NEBULA AND THE ASSOCIATED ULTRALUMINOUS X-RAY SOURCE

Journal Article · Fri Jun 01 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/751/2/104· OSTI ID:22037187

Berghea, C T

We present Spitzer Infrared Spectrograph observations of the ultraluminous X-ray source (ULX) NGC 6946 X-1 and its associated nebula MF 16. This ULX has very similar properties to the famous Holmberg II ULX, the first ULX to show a prominent infrared [O IV] emission line comparable to those found in active galactic nuclei. This paper attempts to constrain the ULX spectral energy distribution (SED) given the optical/UV photometric fluxes and high-resolution X-ray observations. Specifically, Chandra X-ray data and published Hubble optical/UV data are extrapolated to produce a model for the full optical to X-ray SED. The photoionization modeling of the IR lines and ratios is then used to test different accretion spectral models. While either an irradiated disk model or an O-supergiant plus accretion disk model fits the data very well, we prefer the latter because it fits the nebular parameters slightly better. In this second case the accretion disk alone dominates the extreme-UV and X-ray emission, while an O-supergiant is responsible for most of the far-UV emission.

• OSTI ID: 22037187
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 751; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ASTRONOMY
ASTROPHYSICS
BINARY STARS
BLACK HOLES
COMPUTERIZED SIMULATION
COSMIC X-RAY SOURCES
ENERGY SPECTRA
FAR INFRARED RADIATION
GALAXIES
GALAXY NUCLEI
INFRARED SPECTRA
NEBULAE
PHOTOIONIZATION
PHOTOMETRY
PHOTON EMISSION
RESOLUTION
SUPERGIANT STARS
X RADIATION