PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING
Modeling the amplitudes and shapes of the X-ray pulsations observed from hot, rotating neutron stars provides a direct method for measuring neutron-star properties. This technique constitutes an important part of the science case for the forthcoming NICER and proposed LOFT X-ray missions. In this pa...
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| Format: | Article |
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American Astronomical Society
2014
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| Online Access: | http://hdl.handle.net/1721.1/88275 https://orcid.org/0000-0001-8804-8946 |
| _version_ | 1811093431506698240 |
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| author | Psaltis, Dimitrios Ozel, Feryal Chakrabarty, Deepto |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Psaltis, Dimitrios Ozel, Feryal Chakrabarty, Deepto |
| author_sort | Psaltis, Dimitrios |
| collection | MIT |
| description | Modeling the amplitudes and shapes of the X-ray pulsations observed from hot, rotating neutron stars provides a direct method for measuring neutron-star properties. This technique constitutes an important part of the science case for the forthcoming NICER and proposed LOFT X-ray missions. In this paper, we determine the number of distinct observables that can be derived from pulse profile modeling and show that using only bolometric pulse profiles is insufficient for breaking the degeneracy between inferred neutron-star radius and mass. However, we also show that for moderately spinning (300-800 Hz) neutron stars, analysis of pulse profiles in two different energy bands provides additional constraints that allow a unique determination of the neutron-star properties. Using the fractional amplitudes of the fundamental and the second harmonic of the pulse profile in addition to the amplitude and phase difference of the spectral color oscillations, we quantify the signal-to-noise ratio necessary to achieve a specified measurement precision for neutron star radius. We find that accumulating 10[superscript 6] counts in a pulse profile is sufficient to achieve a lsim 5% uncertainty in the neutron star radius, which is the level of accuracy required to determine the equation of state of neutron-star matter. Finally, we formally derive the background limits that can be tolerated in the measurements of the various pulsation amplitudes as a function of the system parameters. |
| first_indexed | 2024-09-23T15:44:57Z |
| format | Article |
| id | mit-1721.1/88275 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:44:57Z |
| publishDate | 2014 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/882752022-09-29T15:54:22Z PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING Psaltis, Dimitrios Ozel, Feryal Chakrabarty, Deepto Massachusetts Institute of Technology. Department of Physics Chakrabarty, Deepto Modeling the amplitudes and shapes of the X-ray pulsations observed from hot, rotating neutron stars provides a direct method for measuring neutron-star properties. This technique constitutes an important part of the science case for the forthcoming NICER and proposed LOFT X-ray missions. In this paper, we determine the number of distinct observables that can be derived from pulse profile modeling and show that using only bolometric pulse profiles is insufficient for breaking the degeneracy between inferred neutron-star radius and mass. However, we also show that for moderately spinning (300-800 Hz) neutron stars, analysis of pulse profiles in two different energy bands provides additional constraints that allow a unique determination of the neutron-star properties. Using the fractional amplitudes of the fundamental and the second harmonic of the pulse profile in addition to the amplitude and phase difference of the spectral color oscillations, we quantify the signal-to-noise ratio necessary to achieve a specified measurement precision for neutron star radius. We find that accumulating 10[superscript 6] counts in a pulse profile is sufficient to achieve a lsim 5% uncertainty in the neutron star radius, which is the level of accuracy required to determine the equation of state of neutron-star matter. Finally, we formally derive the background limits that can be tolerated in the measurements of the various pulsation amplitudes as a function of the system parameters. National Science Foundation (U.S.) (NSF grant AST-1108753) National Science Foundation (U.S.) (NSF CAREER award AST-0746549) National Science Foundation (U.S.) (Chandra Theory grant TM2-13002X) Radcliffe Institute for Advanced Study Harvard-Smithsonian Center for Astrophysics. Theoretical Astrophysics Division. Institute for Theory and Computation 2014-07-11T17:04:58Z 2014-07-11T17:04:58Z 2014-06 2013-12 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/88275 Psaltis, Dimitrios, Feryal Özel, and Deepto Chakrabarty. “PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING.” The Astrophysical Journal 787, no. 2 (June 1, 2014): 136. https://orcid.org/0000-0001-8804-8946 en_US http://dx.doi.org/10.1088/0004-637X/787/2/136 Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Astronomical Society arXiv |
| spellingShingle | Psaltis, Dimitrios Ozel, Feryal Chakrabarty, Deepto PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title | PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title_full | PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title_fullStr | PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title_full_unstemmed | PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title_short | PROSPECTS FOR MEASURING NEUTRON-STAR MASSES AND RADII WITH X-RAY PULSE PROFILE MODELING |
| title_sort | prospects for measuring neutron star masses and radii with x ray pulse profile modeling |
| url | http://hdl.handle.net/1721.1/88275 https://orcid.org/0000-0001-8804-8946 |
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