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arXiv:2109.00652astro-ph.HE

Discovery of ASKAP J173608.2-321635 as a Highly-Polarized Transient Point Source with the Australian SKA Pathfinder

Ziteng Wang, David L. Kaplan, Tara Murphy, Emil Lenc, Shi Dai, Ewan Barr, Dougal Dobie, B. M. Gaensler, George Heald, James K. Leung, Andrew O'Brien, Sergio Pintaldi, Joshua Pritchard, Nanda Rea, Gregory R. Sivakoff, B. W. Stappers, Adam Stewart, E. Tremou, Yuanming Wang, Patrick A. Woudt, Andrew Zic

Abstract

We report the discovery of a highly-polarized, highly-variable, steep-spectrum radio source, ASKAP J173608.2-321635, located $\sim$4\,deg from the Galactic center in the Galactic plane. The source was detected six times between 2020 January and 2020 September as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients (ASKAP VAST) survey at 888\,MHz. It exhibited a high degree ($\sim 25$\%) of circular polarization when it was visible. We monitored the source with the MeerKAT telescope from 2020 November to 2021 February on a 2--4 week cadence. The source was not detected with MeerKAT before 2021 February 07 when it appeared and reached a peak flux density of 5.6\,mJy. The source was still highly circularly polarized, but also showed up to 80\% linear polarization, and then faded rapidly with a timescale of one day. The rotation measure of the source varied significantly, from $-11.8\pm0.8$\,rad\,m$^{-2}$ to $-64.0\pm1.5$\,rad\,m$^{-2}$, over three days. No X-ray counterpart was found in follow-up \textit{Swift} or \textit{Chandra} observations about a week after the first MeerKAT detection, with upper limits of $\sim 5.0\times10^{31}$\,erg\,s$^{-1}$ (0.3--8\,keV, assuming a distance $\sim10$ kpc). No counterpart is seen in new or archival near-infrared observations down to $J=20.8$\,mag. We discuss possible identifications for ASKAP J173608.2-321635 including a low-mass star/substellar object with extremely low infrared luminosity, a pulsar with scatter-broadened pulses, a transient magnetar, or a Galactic Center Radio Transient: none of these fully explains the observations, which suggests that ASKAP J173608.2-321635 may represent part of a new class of objects being discovered through radio imaging surveys.

arXiv comments
22 pages, 15 figures, Accepted by ApJ
Journal reference
DOI
doi:10.3847/1538-4357/ac2360
Subjects
astro-ph.HEHigh Energy Astrophysical Phenomena

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Linked by 5 identifiable commenters in 6 comments across 2 threads, from Oct 2021 to Oct 2021.

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Discussed in comments2 threads

  1. Strange radio waves emerge from direction of the galactic centre 1 comment

    • Source is here: https://iopscience.iop.org/article/10.3847/1538-4357/ac2360 This is a draft/pre-print version https://arxiv.org/pdf/2109.00652.pdf

      InInteractionView on HNParent context

  2. A variable signal at heart of the Milky Way 5 comments

    • https://arxiv.org/abs/2109.00652

      perihelionsView on HNParent context

    • The ASKAP scans at 888MHz. From the paper, which luckily is publicly available: > It exhibited a high degree (∼ 25%) of circular polarization when it was visible. We monitored the source with the MeerKAT telescope from 2020 November to 2021 February on a 2–4 week cadence. The…

      ud_0View on HNParent context

    • I was also interested about the data (and cryptanalysis on it) – the best I could find with a quick inquiry was the original article published in The Astrophysics Journal: https://iopscience.iop.org/article/10.3847/1538-4357/ac2360 There is an open access version at ArxiV.org…

      peterhilView on HNParent context

    • The original article about the find, that was published in The Astrophysics Journal (linked at the bottom of the article): https://iopscience.iop.org/article/10.3847/1538-4357/ac2360 And open access version at ArxiV.org: https://arxiv.org/pdf/2109.00652.pdf

      peterhilView on HNParent context

    • Anyone have a universally working link to access to the paper ? https://iopscience.iop.org/article/10.3847/1538-4357/ac2360 [edit] Found : https://arxiv.org/abs/2109.00652 Is there some of the signal available so we can analyse the randomness for possible order ?

      deepnetView on HNParent context

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