Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray?
Ultraluminous X-ray sources (ULXs) were once largely believed to be powered by super-Eddington accretion onto stellar-mass black holes, although in some rare cases, ULXs also serve as potential candidates for (sub-Eddington) intermediate-mass black holes. However, a total of eight ULXs have now been...
| Main Authors: | , , , , , , , , , , |
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| Format: | Journal Article |
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2024
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| Online Access: | http://purl.org/au-research/grants/arc/DP200102471 http://hdl.handle.net/20.500.11937/97223 |
| _version_ | 1848766241255194624 |
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| author | Panurach, T. Dage, Kristen Urquhart, R. Plotkin, R.M. Paul, J.D. Bahramian, Arash Brumback, M.C. Galvin, Tim Molina, I. Miller-Jones, James Saikia, P. |
| author_facet | Panurach, T. Dage, Kristen Urquhart, R. Plotkin, R.M. Paul, J.D. Bahramian, Arash Brumback, M.C. Galvin, Tim Molina, I. Miller-Jones, James Saikia, P. |
| author_sort | Panurach, T. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Ultraluminous X-ray sources (ULXs) were once largely believed to be powered by super-Eddington accretion onto stellar-mass black holes, although in some rare cases, ULXs also serve as potential candidates for (sub-Eddington) intermediate-mass black holes. However, a total of eight ULXs have now been confirmed to be powered by neutron stars, thanks to observed pulsations, and may act as contaminants for the radio/X-ray selection of intermediate-mass black holes. Here, we present the first comprehensive radio study of seven known neutron star ULXs using new and archival data from the Karl G. Jansky Very Large Array and the Australia Telescope Compact Array, combined with the literature. Across this sample, there is only one confident radio detection, from the Galactic neutron star ULX Swift J0243.6+6124. The other six objects in our sample are extragalactic, and only one has coincident radio emission, which we conclude is most likely contamination from a background H ii region. We conclude that with current facilities, neutron star ULXs do not produce significant enough radio emission to cause them to be misidentified as radio-/X-ray-selected intermediate-mass black hole candidates. Thus, if background star formation has been properly considered, the current study indicates that a ULX with a compact radio counterpart is not likely to be a neutron star. |
| first_indexed | 2025-11-14T11:48:01Z |
| format | Journal Article |
| id | curtin-20.500.11937-97223 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T11:48:01Z |
| publishDate | 2024 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-972232025-04-30T02:11:48Z Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? Panurach, T. Dage, Kristen Urquhart, R. Plotkin, R.M. Paul, J.D. Bahramian, Arash Brumback, M.C. Galvin, Tim Molina, I. Miller-Jones, James Saikia, P. Ultraluminous X-ray sources (ULXs) were once largely believed to be powered by super-Eddington accretion onto stellar-mass black holes, although in some rare cases, ULXs also serve as potential candidates for (sub-Eddington) intermediate-mass black holes. However, a total of eight ULXs have now been confirmed to be powered by neutron stars, thanks to observed pulsations, and may act as contaminants for the radio/X-ray selection of intermediate-mass black holes. Here, we present the first comprehensive radio study of seven known neutron star ULXs using new and archival data from the Karl G. Jansky Very Large Array and the Australia Telescope Compact Array, combined with the literature. Across this sample, there is only one confident radio detection, from the Galactic neutron star ULX Swift J0243.6+6124. The other six objects in our sample are extragalactic, and only one has coincident radio emission, which we conclude is most likely contamination from a background H ii region. We conclude that with current facilities, neutron star ULXs do not produce significant enough radio emission to cause them to be misidentified as radio-/X-ray-selected intermediate-mass black hole candidates. Thus, if background star formation has been properly considered, the current study indicates that a ULX with a compact radio counterpart is not likely to be a neutron star. 2024 Journal Article http://hdl.handle.net/20.500.11937/97223 10.3847/1538-4357/ad8b9c http://purl.org/au-research/grants/arc/DP200102471 http://creativecommons.org/licenses/by/4.0/ fulltext |
| spellingShingle | Panurach, T. Dage, Kristen Urquhart, R. Plotkin, R.M. Paul, J.D. Bahramian, Arash Brumback, M.C. Galvin, Tim Molina, I. Miller-Jones, James Saikia, P. Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title | Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title_full | Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title_fullStr | Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title_full_unstemmed | Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title_short | Do Neutron Star Ultraluminous X-Ray Sources Masquerade as Intermediate-mass Black Holes in Radio and X-Ray? |
| title_sort | do neutron star ultraluminous x-ray sources masquerade as intermediate-mass black holes in radio and x-ray? |
| url | http://purl.org/au-research/grants/arc/DP200102471 http://hdl.handle.net/20.500.11937/97223 |