Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231
We report the discovery of two new Galactic accreting compact objects consistent with the respective positions of the unassociated Fermi-LAT γ -ray sources 4FGL J0639.1-8009 and 4FGL J1824.2+1231. A combination of new and archival X-ray data from Chandra, XMM-Newton, Swift/XRT, and eROSITA reveals a...
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adc128 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849726411187683328 |
|---|---|
| author | Rebecca Kyer Subhroja Roy Jay Strader Ryan Urquhart Isabella Molina Peter Craig Laura Chomiuk |
| author_facet | Rebecca Kyer Subhroja Roy Jay Strader Ryan Urquhart Isabella Molina Peter Craig Laura Chomiuk |
| author_sort | Rebecca Kyer |
| collection | DOAJ |
| description | We report the discovery of two new Galactic accreting compact objects consistent with the respective positions of the unassociated Fermi-LAT γ -ray sources 4FGL J0639.1-8009 and 4FGL J1824.2+1231. A combination of new and archival X-ray data from Chandra, XMM-Newton, Swift/XRT, and eROSITA reveals a variable X-ray source in each γ -ray error ellipse. Both candidate counterparts show power-law spectra with photon indices Γ ∼ 1.7–1.9. Optical follow-up photometry and spectroscopy show rapid high-amplitude variability unrelated to orbital motion and persistent accretion disk spectra for both objects. We demonstrate that the properties of these X-ray/optical sources are at odds with the known phenomenology of accreting white dwarfs, but are consistent with the observed properties of the subluminous disk state of transitional millisecond pulsars. This brings the census of confirmed or candidate transitional millisecond pulsars in the Galactic field to nine. We show this potentially represents ≲10% of the total population of transitional millisecond pulsars within 8 kpc. |
| format | Article |
| id | doaj-art-a9fd913f320b4e6c9e46dbf95f239714 |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-a9fd913f320b4e6c9e46dbf95f2397142025-08-20T03:10:10ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01983211210.3847/1538-4357/adc128Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231Rebecca Kyer0https://orcid.org/0009-0006-2411-5162Subhroja Roy1https://orcid.org/0009-0005-5402-8900Jay Strader2https://orcid.org/0000-0002-1468-9668Ryan Urquhart3https://orcid.org/0000-0003-1814-8620Isabella Molina4https://orcid.org/0009-0004-4418-0645Peter Craig5https://orcid.org/0000-0002-3673-0668Laura Chomiuk6https://orcid.org/0000-0002-8400-3705Center for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduCenter for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USA ; rkyer@msu.eduWe report the discovery of two new Galactic accreting compact objects consistent with the respective positions of the unassociated Fermi-LAT γ -ray sources 4FGL J0639.1-8009 and 4FGL J1824.2+1231. A combination of new and archival X-ray data from Chandra, XMM-Newton, Swift/XRT, and eROSITA reveals a variable X-ray source in each γ -ray error ellipse. Both candidate counterparts show power-law spectra with photon indices Γ ∼ 1.7–1.9. Optical follow-up photometry and spectroscopy show rapid high-amplitude variability unrelated to orbital motion and persistent accretion disk spectra for both objects. We demonstrate that the properties of these X-ray/optical sources are at odds with the known phenomenology of accreting white dwarfs, but are consistent with the observed properties of the subluminous disk state of transitional millisecond pulsars. This brings the census of confirmed or candidate transitional millisecond pulsars in the Galactic field to nine. We show this potentially represents ≲10% of the total population of transitional millisecond pulsars within 8 kpc.https://doi.org/10.3847/1538-4357/adc128Millisecond pulsarsCompact binary stars |
| spellingShingle | Rebecca Kyer Subhroja Roy Jay Strader Ryan Urquhart Isabella Molina Peter Craig Laura Chomiuk Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 The Astrophysical Journal Millisecond pulsars Compact binary stars |
| title | Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 |
| title_full | Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 |
| title_fullStr | Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 |
| title_full_unstemmed | Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 |
| title_short | Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Subluminous Disk State: 4FGL J0639.1-8009 and 4FGL J1824.2+1231 |
| title_sort | multiwavelength evidence for two new candidate transitional millisecond pulsars in the subluminous disk state 4fgl j0639 1 8009 and 4fgl j1824 2 1231 |
| topic | Millisecond pulsars Compact binary stars |
| url | https://doi.org/10.3847/1538-4357/adc128 |
| work_keys_str_mv | AT rebeccakyer multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT subhrojaroy multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT jaystrader multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT ryanurquhart multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT isabellamolina multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT petercraig multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 AT laurachomiuk multiwavelengthevidencefortwonewcandidatetransitionalmillisecondpulsarsinthesubluminousdiskstate4fglj063918009and4fglj182421231 |