Abstract for Proposal 096361

Detailed follow-up studies of compact object transients detected with SVOM

Compact objects are often faint and thus difficult to detect and study, except during a high state. To catch high states requires continually surveying the whole sky, which is possible following the launch of the French-Chinese mission SVOM on June 22nd 2024. Observations during commissioning have already revealed rare gamma-ray bursts, X-ray binary outbursts and magnetar bursts. We request up to five target of opportunity observations, using EPIC full frame, RGS and OM in UVW1, to follow new transients once too faint for SVOM. These data will help refine source positions, study the late evolution of the outbursts, including finding quasi-periodic eruptions, etc, and obtain high quality spectra/lightcurves and search for pulsations, to ultimately constrain the physics of these objects.



Details on Observing Strategy and Trigger Criteria
We will trigger on up to 5 different transients detected with SVOM that will have different accretion and ejection regimes. The trigger criteria and reaction times are different for each. They are as follows: Short gamma-ray burst : criteria : to be detected at high redshift, trigger within 1 day. Long gamma-ray burst: criteria : to be detected at high redshift and counterpart detected with the X-ray telescope on board SVOM (MXT), trigger within two days, followed by a second pointing two days later. Tidal disruption event (TDE): criteria: hard TDE or detected with the MXT, trigger within a few days. Ultra luminous X-ray source: criteria : to be detected with MXT, trigger within a few days. X-ray binary/Cataclysmic variable: to be detected with MXT, trigger within a few days. Magnetar: criteria : to be detected with MXT, trigger within a few days.