DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR
We present spectral analysis of Nuclear Spectroscopic Telescope Array and Swift observations of Cep X-4 during its outburst in 2014. We observed the source once during the peak of the outburst and once during the decay, finding good agreement in the spectral shape between the observations. We descri...
| Main Authors: | , , , , , , , , , , , , , , , , , , |
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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/1721.1/98373 https://orcid.org/0000-0003-2538-0188 |
| _version_ | 1826200179150159872 |
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| author | Pottschmidt, K. Miyasaka, Hiromasa Bhalerao, V. Bachetti, M. Boggs, S. E. Christensen, F. E. Craig, W. W. Hailey, C. J. Harrison, F. A. Kennea, Jamie A. Rahoui, F. Stern, D. Tendulkar, S. P. Tomsick, J. A. Walton, D. J. Wilms, J. Zhang, W. W. Furst, F. Grinberg, Victoria |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Pottschmidt, K. Miyasaka, Hiromasa Bhalerao, V. Bachetti, M. Boggs, S. E. Christensen, F. E. Craig, W. W. Hailey, C. J. Harrison, F. A. Kennea, Jamie A. Rahoui, F. Stern, D. Tendulkar, S. P. Tomsick, J. A. Walton, D. J. Wilms, J. Zhang, W. W. Furst, F. Grinberg, Victoria |
| author_sort | Pottschmidt, K. |
| collection | MIT |
| description | We present spectral analysis of Nuclear Spectroscopic Telescope Array and Swift observations of Cep X-4 during its outburst in 2014. We observed the source once during the peak of the outburst and once during the decay, finding good agreement in the spectral shape between the observations. We describe the continuum using a power law with a Fermi–Dirac cutoff at high energies. Cep X-4 has a very strong cyclotron resonant scattering feature (CRSF) around 30 keV. A simple absorption-like line with a Gaussian optical depth or a pseudo-Lorentzian profile both fail to describe the shape of the CRSF accurately, leaving significant deviations at the red side of the line. We characterize this asymmetry with a second absorption feature around 19 keV. The line energy of the CRSF, which is not influenced by the addition of this feature, shows a small but significant positive luminosity dependence. With luminosities between (1–6) × 10[superscript 36] erg s[superscript −1], Cep X-4 is below the theoretical limit where such a correlation is expected. This behavior is similar to Vela X-1 and we discuss parallels between the two systems. |
| first_indexed | 2024-09-23T11:32:22Z |
| format | Article |
| id | mit-1721.1/98373 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:32:22Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/983732022-10-01T04:16:42Z DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR Pottschmidt, K. Miyasaka, Hiromasa Bhalerao, V. Bachetti, M. Boggs, S. E. Christensen, F. E. Craig, W. W. Hailey, C. J. Harrison, F. A. Kennea, Jamie A. Rahoui, F. Stern, D. Tendulkar, S. P. Tomsick, J. A. Walton, D. J. Wilms, J. Zhang, W. W. Furst, F. Grinberg, Victoria MIT Kavli Institute for Astrophysics and Space Research Grinberg, Victoria We present spectral analysis of Nuclear Spectroscopic Telescope Array and Swift observations of Cep X-4 during its outburst in 2014. We observed the source once during the peak of the outburst and once during the decay, finding good agreement in the spectral shape between the observations. We describe the continuum using a power law with a Fermi–Dirac cutoff at high energies. Cep X-4 has a very strong cyclotron resonant scattering feature (CRSF) around 30 keV. A simple absorption-like line with a Gaussian optical depth or a pseudo-Lorentzian profile both fail to describe the shape of the CRSF accurately, leaving significant deviations at the red side of the line. We characterize this asymmetry with a second absorption feature around 19 keV. The line energy of the CRSF, which is not influenced by the addition of this feature, shows a small but significant positive luminosity dependence. With luminosities between (1–6) × 10[superscript 36] erg s[superscript −1], Cep X-4 is below the theoretical limit where such a correlation is expected. This behavior is similar to Vela X-1 and we discuss parallels between the two systems. 2015-09-08T11:53:34Z 2015-09-08T11:53:34Z 2015-06 2015-04 Article http://purl.org/eprint/type/JournalArticle 2041-8213 2041-8205 http://hdl.handle.net/1721.1/98373 Furst, F., K. Pottschmidt, H. Miyasaka, V. Bhalerao, M. Bachetti, S. E. Boggs, F. E. Christensen, et al. “DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR.” The Astrophysical Journal 806, no. 2 (June 15, 2015): L24. © 2015 The American Astronomical Society https://orcid.org/0000-0003-2538-0188 en_US http://dx.doi.org/10.1088/2041-8205/806/2/l24 The Astrophysical Journal. Letters 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 IOP Publishing |
| spellingShingle | Pottschmidt, K. Miyasaka, Hiromasa Bhalerao, V. Bachetti, M. Boggs, S. E. Christensen, F. E. Craig, W. W. Hailey, C. J. Harrison, F. A. Kennea, Jamie A. Rahoui, F. Stern, D. Tendulkar, S. P. Tomsick, J. A. Walton, D. J. Wilms, J. Zhang, W. W. Furst, F. Grinberg, Victoria DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title | DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title_full | DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title_fullStr | DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title_full_unstemmed | DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title_short | DISTORTED CYCLOTRON LINE PROFILE IN CEP X-4 AS OBSERVED BY NuSTAR |
| title_sort | distorted cyclotron line profile in cep x 4 as observed by nustar |
| url | http://hdl.handle.net/1721.1/98373 https://orcid.org/0000-0003-2538-0188 |
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