Suzaku Observations of 4U 1957+11 : Potentially the Most Rapidly Spinning Black Hole in (the Halo of) the Galaxy
- Author
- Miller, Jon
- Published
- [2011].
- Physical Description
- 1 electronic document
- Additional Creators
- Wilms, Joern, Nowak, Michael A., Pottschmidt, Katja, Schulz, Norbert, and Maitra, Dipankar
Online Version
- hdl.handle.net , Connect to this object online.
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- Unclassified, Unlimited, Publicly available.
Free-to-read Unrestricted online access - Summary
- We present three Suzaku observations of the black hole candidate 4U 1957+11 (V 1408 Aql) - a source that exhibits some of. the simplest and cleanest examples of soft, disk-dominated spectra. 4U 1957+ II also presents among the. highest peak temperatures found from disk-dominated spectra. Such temperatures may be associated with rapid black hole spin. The 4U 1957+11 spectra also require a very low normalization, which can be explained by a combination of small inner disk radius and a large distance (> 10 kpc) which places 4U 1957+ 11 well into the Galactic halo. We perform Joint fits to the Suzaku spectra with both relativistic and Comptonized disk models. Assuming a low mass black hole and the nearest distance (3 Stellar Mass, 10 kpc), the dimensionless spin parameter a* = Jc/GM(sup 2)> or approx. 0.9. Higher masses and farther distances yield a* approx. = 1. Similar conclusions are reached with Comptonization models; they imply a combination of small inner disk radii (or, equivalently, rapid spin) and large distance. Low spin cannot be recovered unless 4U 1957+11 is a low mass black hole that is at the unusually large distance of > or approx.40 kpc. We speculate whether the suggested maximal spin is related to how the system came to reside in the halo.
- Other Subject(s)
- Collection
- NASA Technical Reports Server (NTRS) Collection.
- Note
- Document ID: 20110023498.
GSFC.JA.5436.2011. - Terms of Use and Reproduction
- Copyright, Distribution under U.S. Government purpose rights.
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