Saved in:
| Main Authors: | , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2405.13183 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866909208159453184 |
|---|---|
| author | Weatherhead, Kierra J. Stil, Jeroen M. Rugel, Michael Peters, Wendy M. Anderson, Loren Barnes, Ashley Beuther, Henrik Clarke, Tracy E. Dzib, Sergio A. Goldsmith, Paul Menten, Karl M. Nyland, Kristina E. Sormani, Mattia C. Urquhart, James |
| author_facet | Weatherhead, Kierra J. Stil, Jeroen M. Rugel, Michael Peters, Wendy M. Anderson, Loren Barnes, Ashley Beuther, Henrik Clarke, Tracy E. Dzib, Sergio A. Goldsmith, Paul Menten, Karl M. Nyland, Kristina E. Sormani, Mattia C. Urquhart, James |
| contents | The radio transient ASKAP J173608.2-321735, at the position (l,b)= (356.0872,-0.0390), was serendipitously observed by The HI/OH/Recombination Line Survey of the Galactic Center (THOR-GC) at three epochs in March 2020, April 2020 and February 2021. The source was detected only on 2020 April 11 with flux density 20.6 +/- 1.1 mJy at 1.23 GHz and in-band spectral index alpha = -3.1 +/- 0.2. The commensal VLA Low-band Ionsophere and Transient Experiment (VLITE) simultaneously detected the source at 339 MHz with a flux density 122.6 +/- 20.4 mJy, indicating a spectral break below 1 GHz. The rotation measure in April 2020 was 63.9 +/- 0.3rad/m2, which almost triples the range of the variable rotation measure observed by Wang et al. (2021) to ~130 rad/m2. The polarization angle, corrected for Faraday rotation, was 97 +/- 6 degrees. The 1.23 GHz linear polarization was 76.7% +/- 3.9% with wavelength-dependent depolarization indicating Faraday depth dispersion sigma_phi = 4.8^{+0.5}_{-0.7} rad/m2. We find an upper limit to circular polarization |V|/I < 10.1%. Interpretation of the data in terms of diffractive scattering of radio waves by a plasma near the source indicates electron density and line-of-sight magnetic field strength within a factor 3 of n_e ~2 cm^{-3} and B_par ~2 x 10^5 microgauss. Combined with causality limits to the size of the source, these parameters are consistent with the low-frequency spectral break resulting from synchrotron self-absorption, not free-free absorption. A possible interpretation of the source is a highly supersonic neutron star interacting with a changing environment. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2405_13183 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Spectrum and polarization of the Galactic center radio transient ASKAP J173608.2-321635 from THOR-GC and VLITE Weatherhead, Kierra J. Stil, Jeroen M. Rugel, Michael Peters, Wendy M. Anderson, Loren Barnes, Ashley Beuther, Henrik Clarke, Tracy E. Dzib, Sergio A. Goldsmith, Paul Menten, Karl M. Nyland, Kristina E. Sormani, Mattia C. Urquhart, James Astrophysics of Galaxies High Energy Astrophysical Phenomena The radio transient ASKAP J173608.2-321735, at the position (l,b)= (356.0872,-0.0390), was serendipitously observed by The HI/OH/Recombination Line Survey of the Galactic Center (THOR-GC) at three epochs in March 2020, April 2020 and February 2021. The source was detected only on 2020 April 11 with flux density 20.6 +/- 1.1 mJy at 1.23 GHz and in-band spectral index alpha = -3.1 +/- 0.2. The commensal VLA Low-band Ionsophere and Transient Experiment (VLITE) simultaneously detected the source at 339 MHz with a flux density 122.6 +/- 20.4 mJy, indicating a spectral break below 1 GHz. The rotation measure in April 2020 was 63.9 +/- 0.3rad/m2, which almost triples the range of the variable rotation measure observed by Wang et al. (2021) to ~130 rad/m2. The polarization angle, corrected for Faraday rotation, was 97 +/- 6 degrees. The 1.23 GHz linear polarization was 76.7% +/- 3.9% with wavelength-dependent depolarization indicating Faraday depth dispersion sigma_phi = 4.8^{+0.5}_{-0.7} rad/m2. We find an upper limit to circular polarization |V|/I < 10.1%. Interpretation of the data in terms of diffractive scattering of radio waves by a plasma near the source indicates electron density and line-of-sight magnetic field strength within a factor 3 of n_e ~2 cm^{-3} and B_par ~2 x 10^5 microgauss. Combined with causality limits to the size of the source, these parameters are consistent with the low-frequency spectral break resulting from synchrotron self-absorption, not free-free absorption. A possible interpretation of the source is a highly supersonic neutron star interacting with a changing environment. |
| title | Spectrum and polarization of the Galactic center radio transient ASKAP J173608.2-321635 from THOR-GC and VLITE |
| topic | Astrophysics of Galaxies High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2405.13183 |