On the Characterization of Ultraluminous X-ray Sources with Current and Future Missions
- Paper number
IAC-07-A3.1.09
- Author
Ms. Diane Wong, University of California at Berkeley, United States
- Year
2007
- Abstract
The Chandra X-ray Observatory was launched in July 1999. Operating in the 0.1 -10 keV energy range, it has on board several instruments: AXAF CCD Imaging Spectrometer (ACIS), High Resolution Camera (HRC), High Energy Transmission Grating Spectrometer (HETGS) and Low Energy Transmission Grating Spectrometer (LETGS). ACIS has been instrumental in finding a new class of objects, ultraluminous X-ray sources, ULXs.
ULXs are non-nuclear point X-ray sources with X-ray luminosities intermediate between those of stellar mass black holes and supermassive black holes. ULXs have generated much interest in the past $ \sim$ five years: As mentioned above,on the observational front, the advent of Chandra(better pointing and high spatial resolution ($<$ 1 arcsec)) has allowed isolation of the ULX phenomenon. Also, theorists have proposed viable mechanisms of creating the new class ofintermediate-mass black holes (100-1000 solar masses) that must be necessary if accretion onto these ULXs is to obey the Eddington limit.
The multi-wavelength approach to identifying intermediate-mass black holes has been under-utilized until now: I present the latest results in my ongoing multi-wavelength search for intermediate-mass black holes. Using Keck spectroscopy and analysis of the X-ray data, I have identified dozens of the ULXs from the Colbert \& Ptak (2002) and Swartz et al. (2004) catalogs.
This is a large-scale optical follow-up project of ULXs. Thus, I am able to discuss their statistical properties. In addition to their statistical properties, I have conducted { \}it detailed studies of a few ULXs. For the first time, I have evidence on the existence of intermediate-mass black holes,based on line-of-sight velocities and high-ionization lines present in the spectra of these choice candidates.
Finally, I will discuss the science drivers (namely the distinguishing features of intermediate-mass black holes versus stellar mass black holes) for ULX studies with future space-based missions. Clearly, high angular resolution will be needed to continue the type of discoveries that have been made with Chandra. But in addition, spectral and timing resolution are other technical specifications to be considered. I will discuss future X-ray missions (e.g.Constellation-X and XEUS; even further in the future, Micro-Arcsecond X-ray Imaging Mission [MAXIM] and Generation-X) in relation to how they can enlighten us on the topic of ULXs.
- Abstract document
- Manuscript document
IAC-07-A3.1.09.pdf (🔒 authorized access only).
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