SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY
We present three Suzaku observations of the black hole candidate 4U 1957+11 (V1408 Aql)—a source that exhibits some of the simplest and cleanest examples of soft, disk-dominated spectra. 4U 1957+11 also presents among the highest peak temperatures found from disk-dominated spectra. Such temperatures...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/95455 |
| _version_ | 1826197569526562816 |
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| author | Nowak, Michael A. Pottschmidt, Katja Maitra, Dipankar Miller, Jon Schulz, Norbert S. Wilms, Jorn |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Nowak, Michael A. Pottschmidt, Katja Maitra, Dipankar Miller, Jon Schulz, Norbert S. Wilms, Jorn |
| author_sort | Nowak, Michael A. |
| collection | MIT |
| description | We present three Suzaku observations of the black hole candidate 4U 1957+11 (V1408 Aql)—a source that exhibits some of the simplest and cleanest examples of soft, disk-dominated spectra. 4U 1957+11 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 M [subscript ☉], 10 kpc), the dimensionless spin parameter a* ≡ Jc/GM [superscript 2] [> over ~] 0.9. Higher masses and farther distances yield a* ≈ 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 [> over ~] 40 kpc. We speculate whether the suggested maximal spin is related to how the system came to reside in the halo. |
| first_indexed | 2024-09-23T10:49:41Z |
| format | Article |
| id | mit-1721.1/95455 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:49:41Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
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| spelling | mit-1721.1/954552022-09-27T15:16:09Z SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY Nowak, Michael A. Pottschmidt, Katja Maitra, Dipankar Miller, Jon Schulz, Norbert S. Wilms, Jorn MIT Kavli Institute for Astrophysics and Space Research Nowak, Michael A. Schulz, Norbert S. We present three Suzaku observations of the black hole candidate 4U 1957+11 (V1408 Aql)—a source that exhibits some of the simplest and cleanest examples of soft, disk-dominated spectra. 4U 1957+11 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 M [subscript ☉], 10 kpc), the dimensionless spin parameter a* ≡ Jc/GM [superscript 2] [> over ~] 0.9. Higher masses and farther distances yield a* ≈ 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 [> over ~] 40 kpc. We speculate whether the suggested maximal spin is related to how the system came to reside in the halo. United States. National Aeronautics and Space Administration (Grant NNX10AR94G) United States. National Aeronautics and Space Administration (Grant SV3-73016) 2015-02-20T18:06:25Z 2015-02-20T18:06:25Z 2011-12 2011-05 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/95455 Nowak, Michael A., Jorn Wilms, Katja Pottschmidt, Norbert Schulz, Dipankar Maitra, and Jon Miller. “SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY.” The Astrophysical Journal 744, no. 2 (December 20, 2011): 107. © 2012 The American Astronomical Society en_US http://dx.doi.org/10.1088/0004-637x/744/2/107 The Astrophysical Journal 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. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Nowak, Michael A. Pottschmidt, Katja Maitra, Dipankar Miller, Jon Schulz, Norbert S. Wilms, Jorn SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title | SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title_full | SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title_fullStr | SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title_full_unstemmed | SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title_short | SUZAKU OBSERVATIONS OF 4U 1957+11: POTENTIALLY THE MOST RAPIDLY SPINNING BLACK HOLE IN (THE HALO OF) THE GALAXY |
| title_sort | suzaku observations of 4u 1957 11 potentially the most rapidly spinning black hole in the halo of the galaxy |
| url | http://hdl.handle.net/1721.1/95455 |
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