Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary
Large widefield surveys make possible the serendipitous discovery of rare subclasses of pulsars. One such class are ‘spider’-type pulsar binaries, comprised of a pulsar in a compact orbit with a low-mass (sub)stellar companion. In a search for circularly polarized radio sources in Australian Square...
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Journal Article |
| Published: |
2024
|
| Online Access: | http://purl.org/au-research/grants/arc/FT190100231 http://hdl.handle.net/20.500.11937/96168 |
| _version_ | 1848766105580994560 |
|---|---|
| author | Zic, A. Wang, Ziteng Lenc, E. Kaplan, D.L. Murphy, T. Ridolfi, A. Sengar, R. Hurley-Walker, Natasha Dobie, D. Leung, J.K. Pritchard, J. Wang, Y. |
| author_facet | Zic, A. Wang, Ziteng Lenc, E. Kaplan, D.L. Murphy, T. Ridolfi, A. Sengar, R. Hurley-Walker, Natasha Dobie, D. Leung, J.K. Pritchard, J. Wang, Y. |
| author_sort | Zic, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Large widefield surveys make possible the serendipitous discovery of rare subclasses of pulsars. One such class are ‘spider’-type pulsar binaries, comprised of a pulsar in a compact orbit with a low-mass (sub)stellar companion. In a search for circularly polarized radio sources in Australian Square Kilometre Array Pathfinder (ASKAP) Pilot Survey observations, we discovered highly variable and circularly polarized emission from a radio source within the error region of the γ -ray source 4FGL J1646.5−4406. The variability is consistent with the eclipse of a compact, steep-spectrum source behind ablated material from a companion in an ∼5.3 h binary orbit. Based on the eclipse properties and spatial coincidence with 4FGL J1646.5−4406, we argue that the source is likely a recycled pulsar in a ‘redback’ binary system. Using properties of the eclipses from ASKAP and Murchison Widefield Array observations, we provide broad constraints on the properties of the eclipse medium. We identified a potential optical/infrared counterpart in archival data consistent with a variable low-mass star. Using the Parkes radio telescope ‘Murriyang’ and the Meer Karoo Array Telescope (MeerKAT), we searched extensively for radio pulsations but yielded no viable detections of pulsed emission. We suggest that the non-detection of pulses is due to scattering in the intra-binary material, but scattering from the interstellar medium can also plausibly explain the pulse non-detections if the interstellar dispersion measure exceeds ∼600 pc cm−3. Orbital constraints derived from optical observations of the counterpart would be highly valuable for future γ -ray pulsation searches, which may confirm the source nature as a pulsar. |
| first_indexed | 2025-11-14T11:45:51Z |
| format | Journal Article |
| id | curtin-20.500.11937-96168 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T11:45:51Z |
| publishDate | 2024 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-961682024-11-07T04:59:14Z Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary Zic, A. Wang, Ziteng Lenc, E. Kaplan, D.L. Murphy, T. Ridolfi, A. Sengar, R. Hurley-Walker, Natasha Dobie, D. Leung, J.K. Pritchard, J. Wang, Y. Large widefield surveys make possible the serendipitous discovery of rare subclasses of pulsars. One such class are ‘spider’-type pulsar binaries, comprised of a pulsar in a compact orbit with a low-mass (sub)stellar companion. In a search for circularly polarized radio sources in Australian Square Kilometre Array Pathfinder (ASKAP) Pilot Survey observations, we discovered highly variable and circularly polarized emission from a radio source within the error region of the γ -ray source 4FGL J1646.5−4406. The variability is consistent with the eclipse of a compact, steep-spectrum source behind ablated material from a companion in an ∼5.3 h binary orbit. Based on the eclipse properties and spatial coincidence with 4FGL J1646.5−4406, we argue that the source is likely a recycled pulsar in a ‘redback’ binary system. Using properties of the eclipses from ASKAP and Murchison Widefield Array observations, we provide broad constraints on the properties of the eclipse medium. We identified a potential optical/infrared counterpart in archival data consistent with a variable low-mass star. Using the Parkes radio telescope ‘Murriyang’ and the Meer Karoo Array Telescope (MeerKAT), we searched extensively for radio pulsations but yielded no viable detections of pulsed emission. We suggest that the non-detection of pulses is due to scattering in the intra-binary material, but scattering from the interstellar medium can also plausibly explain the pulse non-detections if the interstellar dispersion measure exceeds ∼600 pc cm−3. Orbital constraints derived from optical observations of the counterpart would be highly valuable for future γ -ray pulsation searches, which may confirm the source nature as a pulsar. 2024 Journal Article http://hdl.handle.net/20.500.11937/96168 10.1093/mnras/stae033 http://purl.org/au-research/grants/arc/FT190100231 http://creativecommons.org/licenses/by/4.0/ fulltext |
| spellingShingle | Zic, A. Wang, Ziteng Lenc, E. Kaplan, D.L. Murphy, T. Ridolfi, A. Sengar, R. Hurley-Walker, Natasha Dobie, D. Leung, J.K. Pritchard, J. Wang, Y. Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title | Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title_full | Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title_fullStr | Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title_full_unstemmed | Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title_short | Discovery of radio eclipses from 4FGL J1646.5−4406: a new candidate redback pulsar binary |
| title_sort | discovery of radio eclipses from 4fgl j1646.5−4406: a new candidate redback pulsar binary |
| url | http://purl.org/au-research/grants/arc/FT190100231 http://hdl.handle.net/20.500.11937/96168 |