Multi-wavelength follow up observations of SN 2023xrs

ATel #16375; Luca Izzo (INAF-OACn & DARK/NBI), James Leung (U. Toronto), Ziteng Wang (ICRAR/Curtin), Katie Auchettl (U. Melbourne), Fabio De Colle (UNAM), Aprajita Hajela (DARK/NBI), Keiichi Maeda (Kyoto U.), Tara Murphy (U. Sydney)
on 11 Dec 2023; 20:40 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Luca Izzo (luca.izzo@gmail.com)

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We report radio observations of SN 2023xrs (AN 2023-312) conducted with the Australia Telescope Compact Array (ATCA), project code C3448. The observations were conducted from 12:30 to 18:30 UT on 2023 November 23, centered on frequencies 5.5, 9.0, and 16.7 GHz. From preliminary analysis, we report non-detections in all observed bands, with the following 3-sigma upper limits: < 138 micro-Jy/beam at 5.5 GHz, < 165 micro-Jy/beam at 9 GHz, < 582 micro-Jy/beam at 16.7 GHz.

We have also observed SN 2023xrs with the X-ray Telescope on board the Neil Gehrels Swift observatory (GI prop. 1922064). The observations were conducted along five different epochs, ranging from 2023 November 19 to November 27, with a total exposure time on-source of 9.35 ks. From a preliminary analysis of the stacked X-ray image, we report no X-ray source at the position of SN 2023xrs, with a one-sigma upper limit of 0.0013 ctg/s. Assuming a power-law spectrum with photon index gamma=2, and a Galactic column density of NH = 1.59x10^22 cm^-2 (Kalberla et al. 2005 A&A, 440, 775), we obtain an unabsorbed flux (0.3-10.0 keV) limit of 1.6x10^-13 erg/cm^2/s.

An optical spectrum of SN 2023xrs has also been obtained with the WiFES spectrograph at the Australian National University 2.3-meter telescope located at Siding Spring (AU). The spectrum consists of a single exposure of 750s in both grisms B3000 and R3000. Observations started on December 8, at 11:14 UT. The spectrum shows typical absorption lines observed in type-Ic SNe, including Fe II, Si II, O I, and Ca II NIR, at an expanding velocity of ~ 12,000 km/s, as measured from Ca II NIR and O I 7775 Ang. Using SNID (Blondin & Tonry 2007 ApJ, 666, 1024), we find a best match with the type-Ic SN 2004aw at 5 days from its peak brightness.

We thank CSIRO staff for rapidly scheduling, supporting, and executing these observations. We also thank the Neil Gehrels Swift Observatory team for the rapid scheduling of these ToO observations. K.A. would also like to acknowledge Ian Price and Chris Lidman with the ANU 2.3-metre telescope. The automation of the ANU 2.3-meter telescope was made possible through funding provided by the Centre of Gravitational Astrophysics at the Australian National University.