Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676
We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748–676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude was 15% (rms). The dynamic power density spe...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2013
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| Online Access: | http://hdl.handle.net/1721.1/76190 https://orcid.org/0000-0001-8804-8946 |
| _version_ | 1826189582407827456 |
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| author | Galloway, Duncan K. Lin, Jinrong Chakrabarty, Deepto Hartman, Jacob M., Ph. D. Massachusetts Institute of Technology |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Galloway, Duncan K. Lin, Jinrong Chakrabarty, Deepto Hartman, Jacob M., Ph. D. Massachusetts Institute of Technology |
| author_sort | Galloway, Duncan K. |
| collection | MIT |
| description | We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748–676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude was 15% (rms). The dynamic power density spectrum for each burst revealed an increase in frequency of ≈1-2 Hz while the oscillation was present. The frequency drift, the high significance of the detections and the almost identical signal frequencies measured in two bursts separated by 11 months, confirms this signal as a burst oscillation similar to those found in 13 other sources to date. We thus conclude that the spin frequency in EXO 0748 – 676 is within a few Hz of 552 Hz, rather than 45 Hz as was suggested from an earlier signal detection by Villarreal & Strohmayer. Consequently, Doppler broadening must significantly affect spectral features arising from the neutron star surface, so that the narrow absorption features previously reported from an XMM-Newton spectrum could not have arisen there. The origin of both the previously reported 45 Hz oscillation and the X-ray absorption lines is now uncertain. |
| first_indexed | 2024-09-23T08:17:55Z |
| format | Article |
| id | mit-1721.1/76190 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:17:55Z |
| publishDate | 2013 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/761902022-09-30T08:50:11Z Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 Galloway, Duncan K. Lin, Jinrong Chakrabarty, Deepto Hartman, Jacob M., Ph. D. Massachusetts Institute of Technology Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Lin, Jinrong Chakrabarty, Deepto We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748–676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude was 15% (rms). The dynamic power density spectrum for each burst revealed an increase in frequency of ≈1-2 Hz while the oscillation was present. The frequency drift, the high significance of the detections and the almost identical signal frequencies measured in two bursts separated by 11 months, confirms this signal as a burst oscillation similar to those found in 13 other sources to date. We thus conclude that the spin frequency in EXO 0748 – 676 is within a few Hz of 552 Hz, rather than 45 Hz as was suggested from an earlier signal detection by Villarreal & Strohmayer. Consequently, Doppler broadening must significantly affect spectral features arising from the neutron star surface, so that the narrow absorption features previously reported from an XMM-Newton spectrum could not have arisen there. The origin of both the previously reported 45 Hz oscillation and the X-ray absorption lines is now uncertain. 2013-01-08T15:56:25Z 2013-01-08T15:56:25Z 2010-02 2009-10 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/76190 Galloway, Duncan K. et al. “Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676.” The Astrophysical Journal 711.2 (2010): L148–L151. Web. 8 Jan. 2013. https://orcid.org/0000-0001-8804-8946 en_US http://dx.doi.org/10.1088/2041-8205/711/2/l148 Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ application/pdf IOP Publishing arXiv |
| spellingShingle | Galloway, Duncan K. Lin, Jinrong Chakrabarty, Deepto Hartman, Jacob M., Ph. D. Massachusetts Institute of Technology Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title | Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title_full | Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title_fullStr | Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title_full_unstemmed | Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title_short | Discovery Of A 552 Hz Burst Oscillation In The Low-Mass X-Ray Binary Exo 0748–676 |
| title_sort | discovery of a 552 hz burst oscillation in the low mass x ray binary exo 0748 676 |
| url | http://hdl.handle.net/1721.1/76190 https://orcid.org/0000-0001-8804-8946 |
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