NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300
We present a spectral analysis of three simultaneous Nuclear Spectroscopy Telescope Array and Swift/XRT observations of the transient Be-neutron star binary KS 1947+300 taken during its outburst in 2013/2014. These broadband observations were supported by Swift/XRT monitoring snapshots every three d...
| Main Authors: | , , , , , , , , , , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2014
|
| Online Access: | http://hdl.handle.net/1721.1/88258 https://orcid.org/0000-0001-8804-8946 |
| _version_ | 1811075942987071488 |
|---|---|
| author | Pottschmidt, Katja Kennea, Jamie A. Bachetti, Matteo Bellm, Eric C. Boggs, Steven E. Chakrabarty, Deepto Christensen, Finn E. Craig, William W. Hailey, Charles J. Harrison, Fiona A. Stern, Daniel Tomsick, John A. Walton, Dominic J. Zhang, William Furst, Felix Wilms, Jorn |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Pottschmidt, Katja Kennea, Jamie A. Bachetti, Matteo Bellm, Eric C. Boggs, Steven E. Chakrabarty, Deepto Christensen, Finn E. Craig, William W. Hailey, Charles J. Harrison, Fiona A. Stern, Daniel Tomsick, John A. Walton, Dominic J. Zhang, William Furst, Felix Wilms, Jorn |
| author_sort | Pottschmidt, Katja |
| collection | MIT |
| description | We present a spectral analysis of three simultaneous Nuclear Spectroscopy Telescope Array and Swift/XRT observations of the transient Be-neutron star binary KS 1947+300 taken during its outburst in 2013/2014. These broadband observations were supported by Swift/XRT monitoring snapshots every three days, which we use to study the evolution of the spectrum over the outburst. We find strong changes of the power-law photon index, which shows a weak trend of softening with increasing X-ray flux. The neutron star shows very strong pulsations with a period of P ≈ 18.8 s. The 0.8-79 keV broadband spectrum can be described by a power law with an exponential cutoff and a blackbody component at low energies. During the second observation we detect a cyclotron resonant scattering feature at 12.5 keV, which is absent in the phase-averaged spectra of observations 1 and 3. Pulse phase-resolved spectroscopy reveals that the strength of the feature changes strongly with pulse phase and is most prominent during the broad minimum of the pulse profile. At the same phases the line also becomes visible in the first and third observation at the same energy. This discovery implies that KS 1947+300 has a magnetic field strength of B ≈ 1.1 × 10[superscript 12](1 + z) G, which is at the lower end of known cyclotron line sources. |
| first_indexed | 2024-09-23T10:13:45Z |
| format | Article |
| id | mit-1721.1/88258 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:13:45Z |
| publishDate | 2014 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/882582022-09-30T19:45:47Z NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 Pottschmidt, Katja Kennea, Jamie A. Bachetti, Matteo Bellm, Eric C. Boggs, Steven E. Chakrabarty, Deepto Christensen, Finn E. Craig, William W. Hailey, Charles J. Harrison, Fiona A. Stern, Daniel Tomsick, John A. Walton, Dominic J. Zhang, William Furst, Felix Wilms, Jorn Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Chakrabarty, Deepto We present a spectral analysis of three simultaneous Nuclear Spectroscopy Telescope Array and Swift/XRT observations of the transient Be-neutron star binary KS 1947+300 taken during its outburst in 2013/2014. These broadband observations were supported by Swift/XRT monitoring snapshots every three days, which we use to study the evolution of the spectrum over the outburst. We find strong changes of the power-law photon index, which shows a weak trend of softening with increasing X-ray flux. The neutron star shows very strong pulsations with a period of P ≈ 18.8 s. The 0.8-79 keV broadband spectrum can be described by a power law with an exponential cutoff and a blackbody component at low energies. During the second observation we detect a cyclotron resonant scattering feature at 12.5 keV, which is absent in the phase-averaged spectra of observations 1 and 3. Pulse phase-resolved spectroscopy reveals that the strength of the feature changes strongly with pulse phase and is most prominent during the broad minimum of the pulse profile. At the same phases the line also becomes visible in the first and third observation at the same energy. This discovery implies that KS 1947+300 has a magnetic field strength of B ≈ 1.1 × 10[superscript 12](1 + z) G, which is at the lower end of known cyclotron line sources. United States. National Aeronautics and Space Administration (Contract NNG08FD06C) 2014-07-11T12:23:08Z 2014-07-11T12:23:08Z 2014-03 2014-02 Article http://purl.org/eprint/type/JournalArticle 2041-8205 2041-8213 http://hdl.handle.net/1721.1/88258 Furst, Felix, Katja Pottschmidt, Jorn Wilms, Jamie Kennea, Matteo Bachetti, Eric Bellm, Steven E. Boggs, et al. “NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300.” The Astrophysical Journal 784, no. 2 (April 1, 2014): L40. https://orcid.org/0000-0001-8804-8946 en_US http://dx.doi.org/10.1088/2041-8205/784/2/l40 The Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf IOP Publishing arXiv |
| spellingShingle | Pottschmidt, Katja Kennea, Jamie A. Bachetti, Matteo Bellm, Eric C. Boggs, Steven E. Chakrabarty, Deepto Christensen, Finn E. Craig, William W. Hailey, Charles J. Harrison, Fiona A. Stern, Daniel Tomsick, John A. Walton, Dominic J. Zhang, William Furst, Felix Wilms, Jorn NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title | NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title_full | NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title_fullStr | NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title_full_unstemmed | NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title_short | NuSTAR DISCOVERY OF A CYCLOTRON LINE IN KS 1947+300 |
| title_sort | nustar discovery of a cyclotron line in ks 1947 300 |
| url | http://hdl.handle.net/1721.1/88258 https://orcid.org/0000-0001-8804-8946 |
| work_keys_str_mv | AT pottschmidtkatja nustardiscoveryofacyclotronlineinks1947300 AT kenneajamiea nustardiscoveryofacyclotronlineinks1947300 AT bachettimatteo nustardiscoveryofacyclotronlineinks1947300 AT bellmericc nustardiscoveryofacyclotronlineinks1947300 AT boggsstevene nustardiscoveryofacyclotronlineinks1947300 AT chakrabartydeepto nustardiscoveryofacyclotronlineinks1947300 AT christensenfinne nustardiscoveryofacyclotronlineinks1947300 AT craigwilliamw nustardiscoveryofacyclotronlineinks1947300 AT haileycharlesj nustardiscoveryofacyclotronlineinks1947300 AT harrisonfionaa nustardiscoveryofacyclotronlineinks1947300 AT sterndaniel nustardiscoveryofacyclotronlineinks1947300 AT tomsickjohna nustardiscoveryofacyclotronlineinks1947300 AT waltondominicj nustardiscoveryofacyclotronlineinks1947300 AT zhangwilliam nustardiscoveryofacyclotronlineinks1947300 AT furstfelix nustardiscoveryofacyclotronlineinks1947300 AT wilmsjorn nustardiscoveryofacyclotronlineinks1947300 |