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Abstract We present a detailed analysis of nearly two decades of optical/UV and X-ray data to study the multi-wavelength pre-explosion properties and post-explosion X-ray properties of nearby SN2023ixf located in M101. We find no evidence of precursor activity in the optical to UV down to a luminosity of$$\lesssim$$$$1.0\times10^{5}\, \textrm{L}_{\odot}$$, while X-ray observations covering nearly 18 yr prior to explosion show no evidence of luminous precursor X-ray emission down to an absorbed 0.3–10.0 keV X-ray luminosity of$$\sim$$$$6\times10^{36}$$erg s$$^{-1}$$. ExtensiveSwiftobservations taken post-explosion did not detect soft X-ray emission from SN2023ixf within the first$$\sim$$3.3 days after first light, which suggests a mass-loss rate for the progenitor of$$\lesssim$$$$5\times10^{-4}\,\textrm{M}_{\odot}$$yr$$^{-1}$$or a radius of$$\lesssim$$$$4\times10^{15}$$cm for the circumstellar material. Our analysis also suggests that if the progenitor underwent a mass-loss episode, this had to occur$$>$$0.5–1.5 yr prior to explosion, consistent with previous estimates.Swiftdetected soft X-rays from SN2023ixf$$\sim$$$$4.25$$days after first light, and it rose to a peak luminosity of$$\sim10^{39}$$erg s$$^{-1}$$after 10 days and has maintained this luminosity for nearly 50 days post first light. This peak luminosity is lower than expected, given the evidence that SN2023ixf is interacting with dense material. However, this might be a natural consequence of an asymmetric circumstellar medium. X-ray spectra derived from merging allSwiftobservations over the first 50 days are best described by a two-component bremsstrahlung model consisting of a heavily absorbed and hotter component similar to that found usingNuSTAR, and a less-absorbed, cooler component. We suggest that this soft component arises from cooling of the forward shock similar to that found in Type IIn SN2010jl.
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MWA rapid follow-up of gravitational wave transients: Prospects for detecting prompt radio counterparts
Abstract We present and evaluate the prospects for detecting coherent radio counterparts to gravitational wave (GW) events using Murchison Widefield Array (MWA) triggered observations. The MWA rapid-response system, combined with its buffering mode ($$\sim$$4 min negative latency), enables us to catch any radio signals produced from seconds prior to hours after a binary neutron star (BNS) merger. The large field of view of the MWA ($$\sim$$$$1\,000\,\textrm{deg}^2$$at 120 MHz) and its location under the high sensitivity sky region of the LIGO-Virgo-KAGRA (LVK) detector network, forecast a high chance of being on-target for a GW event. We consider three observing configurations for the MWA to follow up GW BNS merger events, including a single dipole per tile, the full array, and four sub-arrays. We then perform a population synthesis of BNS systems to predict the radio detectable fraction of GW events using these configurations. We find that the configuration with four sub-arrays is the best compromise between sky coverage and sensitivity as it is capable of placing meaningful constraints on the radio emission from 12.6% of GW BNS detections. Based on the timescales of four BNS merger coherent radio emission models, we propose an observing strategy that involves triggering the buffering mode to target coherent signals emitted prior to, during or shortly following the merger, which is then followed by continued recording for up to three hours to target later time post-merger emission. We expect MWA to trigger on$$\sim$$$$5-22$$BNS merger events during the LVK O4 observing run, which could potentially result in two detections of predicted coherent emission.
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- Award ID(s):
- 1816492
- PAR ID:
- 10545355
- Publisher / Repository:
- Publications of the Astronomical Society of Australia
- Date Published:
- Journal Name:
- Publications of the Astronomical Society of Australia
- Volume:
- 40
- ISSN:
- 1323-3580
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1017/pasa.2023.49
