A search for minute-time-scale flares from the transient AT\,2024wpp

TL;DR

This study conducted a sensitive search for minute-scale flares in the transient AT2024wpp, finding no such flares and setting upper limits on their occurrence, which informs understanding of the diversity and emission mechanisms of 18cow-like events.

Contribution

First systematic search for minute-scale flares in AT2024wpp, providing constraints on flare rates and duty cycle in 18cow-like transients.

Findings

No flares detected in 23 hours of observation.

Upper limit on flare duty cycle is <0.02.

Flare rate lower than about 0.11 per hour.

Abstract

The AT 2018cow-like fast blue optical transient AT2022tsd showed a large number of few-minute-duration, high-luminosity (~10^43 erg/s) flares. We present an intensive search for such flares from another 18cow-like event, AT2024wpp. We have used the Large Array Survey Telescope (LAST) to observe this transient between 28 and 74 days after the approximate time of zero flux. The target was observed for about 23 hours to a sensitivity that allows one to detect 3x10^42 erg/s flares at S/N>5. No optical flares have been found, suggesting a one-sided 2-sigma confidence upper limit of <0.02 on the flare's duty cycle, and flare rate lower than about 0.11/hr. These limits suggest that not all 18cow-like objects display a high rate of minute-timescale luminous flares. This can be explained either by diversity in the 18cow-like population or by viewing angle effects (e.g., beaming), or rather that the optical depth towards the central emitting region did not fall below unity during the particular search window.