MIT Libraries homeMIT Libraries logoDSpace@MIT

MIT
View Item 
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Disk-dominated States of 4U 1957+11: Chandra, XMM-Newton, and RXTE Observations of Ostensibly the Most Rapidly Spinning Galactic Black Hole

Author(s)
Nowak, Michael A.; Juett, Adrienne M.; Homan, Jeroen; Yao, Yangsen; Wilms, Jorn; Schulz, Norbert S.; Canizares, Claude R.; ... Show more Show less
Thumbnail
DownloadCanizares-Disk-dominated states.pdf (1.653Mb)
PUBLISHER_POLICY

Publisher Policy

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.

Terms of use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Metadata
Show full item record
Abstract
We present simultaneous Chandra High-Energy Transmission Gratings (HETG) and Rossi X-ray Timing Explorer (RXTE) observations of a "soft state" of the black hole candidate 4U 1957+11. These spectra, having limited hard X-ray excess, are an excellent test of disk atmosphere models that include effects of black hole spin. The HETG data show, by modeling the broadband continuum and direct fitting of absorption edges, that the disk spectrum is only very mildly absorbed, with N[subscript H] = (1–2) × 10[superscript 21] cm−[superscript 2]. These data additionally reveal λλ13.449 Ne IX absorption consistent with the warm/hot phase of the interstellar medium. The fitted disk model implies an inclined disk around a low-mass black hole rotating with normalized spin a* ≈ 1. We show, however, that pure Schwarzschild models describe the data extremely well, albeit with large disk atmosphere ``color-correction'' factors. Standard correction factors can be attained if one incorporates mild Comptonization. We find that the Chandra observations do not uniquely determine spin, even with this otherwise extremely well-measured, nearly pure disk spectrum. XMM-Newton RXTE observations, taken only six weeks later, are equally unconstraining. This lack of constraint is partly driven by the unknown mass and distance of 4U 1957+11; however, it is also driven by the limited Chandra and XMM-Newton bandpasses. We therefore present a series of 48 RXTE observations taken at different brightness/hardness levels. These data prefer a spin of a* ≈ 1, even when including a mild Comptonization component; however, they also show evolution of the color-correction factors. If the rapid-spin models with standard correction factors are to be believed, then the RXTE observations predict that 4U 1957+11 can range from a 3 M[sun] black hole at 10 kpc with a* ≈ 0.83 to a 16 M[sun] black hole at 22 kpc with a* ≈ 1.
Date issued
2008-12
URI
http://hdl.handle.net/1721.1/71911
Department
MIT Kavli Institute for Astrophysics and Space Research
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Nowak, Michael A. et al. “Disk‐dominated States of 4U 1957+11: Chandra,XMM‐Newton,and RXTE Observations of Ostensibly the Most Rapidly Spinning Galactic Black Hole.” The Astrophysical Journal 689.2 (2008): 1199–1214.
Version: Author's final manuscript
ISSN
0004-637X
1538-4357

Collections
  • MIT Open Access Articles

Browse

All of DSpaceCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

My Account

Login

Statistics

OA StatisticsStatistics by CountryStatistics by Department
MIT Libraries homeMIT Libraries logo

Find us on

Twitter Facebook Instagram YouTube RSS

MIT Libraries navigation

SearchHours & locationsBorrow & requestResearch supportAbout us
PrivacyPermissionsAccessibility
MIT
Massachusetts Institute of Technology
Content created by the MIT Libraries, CC BY-NC unless otherwise noted. Notify us about copyright concerns.