Constraints on Late-time Flaring from Luminous Fast Blue Optical Transients Using the Transiting Exoplanet Survey Satellite and the Zwicky Transient Facility

Jayaraman, R, Ho, AYQ, Fausnaugh, MM, Ofek, E, Perley, DA ORCID: 0000-0001-8472-1996, Konno, R, Kristiansen, M, Chen, TX, Coughlin, MW, Groom, SL, Helou, G, Hinds, KR, Kasliwal, MM, McGrath, Z, Purdum, JN, Sasli, A and Sollerman, J (2026) Constraints on Late-time Flaring from Luminous Fast Blue Optical Transients Using the Transiting Exoplanet Survey Satellite and the Zwicky Transient Facility. The Astrophysical Journal (ApJ), 1009 (2). ISSN 0004-637X

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Abstract

The luminous fast blue optical transient (LFBOT) AT2022tsd exhibited minutes-timescale optical flares in the tens of days following the initial transient event, likely due to a central engine—either an accreting black hole or a magnetar. In this paper, we use data from the Transiting Exoplanet Survey Satellite (TESS) and the Zwicky Transient Facility (ZTF) to constrain the occurrence of similar flares in the 12 (of 14) known LFBOTs that had observational coverage with TESS from tens to thousands of days after the transient’s initial emission. We find seven flare-like signals at the locations of four unique LFBOTs; all seven can likely be attributed to a solar system object (SSO) moving through the TESS aperture. Assuming all seven flares arise from SSOs, for the LFBOT AT2024qfm we rule out flaring with a similar timescale (40–65 days) and luminosity (νLν ∼ 1043 erg s−1) as in AT2022tsd, while for AT2022tsd itself we rule out flares between 380 and 430 days after the initial transient that were as luminous as the earlier flares. This observation suggests that the engine power in AT2022tsd declined or shut off on a timescale of hundreds of days. We also find that there is no late-time activity detectable in TESS thousands of days after the prototype LFBOT, AT2018cow. We discuss our constraints on the duty cycle of such flaring and then present estimates for the number of minutes-duration flares detectable with ongoing and upcoming high-cadence (≪1 day) wide-field surveys.

Item Type:	Article
Uncontrolled Keywords:	5101 Astronomical Sciences; 51 Physical Sciences; 5101 Astronomical Sciences; 51 Physical Sciences; 0201 Astronomical and Space Sciences; 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics; 0306 Physical Chemistry (incl. Structural); Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	IOP Publishing
Date of acceptance:	27 July 2026
Date of first compliant Open Access:	21 October 2026
Date Deposited:	21 Oct 2026 15:13
Last Modified:	21 Oct 2026 15:13
DOI or ID number:	10.3847/1538-4357/ae9b05
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29725

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