Journal article
CHANDRAANDHUBBLE SPACE TELESCOPEOBSERVATIONS OF THE SUPERSOFT ULX IN NGC 247: CANDIDATE FOR STANDARD DISK EMISSION
The Astrophysical journal, Vol.758(2), p.85
10/20/2012
DOI: 10.1088/0004-637X/758/2/85
Abstract
We report on multiwavelength observations of the supersoft ultraluminous X-ray source (ULX) in NGC247 made with the Chandra X-Ray Observatory and Hubble Space Telescope. We aligned the X-ray and optical images using three objects present on both and identified a unique, point-like optical counterpart to the ULX. The X-ray to optical spectrum is well fitted with an irradiated disk model if the extinction measured for Cepheids in NGC247 is used. Assuming only Galactic extinction, the spectrum can be modeled as a standard thin accretion disk. Either result leads to the conclusion that a disk interpretation of the X-ray spectrum is valid, thus the source may be in the X-ray thermal state and contain an intermediate-mass black hole of at least 600 M ⊙. In contrast to other supersoft ULXs that are transient and exhibit a luminosity temperature relation inconsistent with a disk interpretation of the X-ray emission, the NGC247 ULX has a relatively steady flux and all available X-ray data are consistent with emission from a disk in the thermal state. © 2012. The American Astronomical Society. All rights reserved.
Details
- Title: Subtitle
- CHANDRAANDHUBBLE SPACE TELESCOPEOBSERVATIONS OF THE SUPERSOFT ULX IN NGC 247: CANDIDATE FOR STANDARD DISK EMISSION
- Creators
- Lian Tao - Tsinghua UniversityHua Feng - Tsinghua UniversityPhilip Kaaret - University of IowaFabien Grisé - University of IowaJing Jin - Tsinghua University
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.758(2), p.85
- DOI
- 10.1088/0004-637X/758/2/85
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- Institute of Physics (IOP)
- Language
- English
- Date published
- 10/20/2012
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199828202771
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