General information
EP260324a is a long-lived X-ray transient detected by Einstein Probe starting at 2026-03-24T07:04:20 (t0), with an identified optical counterpart ZTF26aapviim/AT2026hir reported by ZTF and confirmed by GIT.
Wavelength coverage
- X-ray: Einstein Probe WXT detections with subsequent FXT observations reported.
- Optical: ZTF detections (including forced photometry) and GIT g'/r' photometry; ATLAS also reported to TNS.
No UV, radio, IR spectroscopy/photometry, gamma-ray, or neutrino observations are mentioned.
Lightcurve and spectrum
- ZTF forced-photometry detection at 2026-03-24T04:17:28 (~3 hours before t0): r = 20.14 ± 0.15 (t0-0.12 d).
- ZTF reports a moderately fast rise of ~0.7 mag/day.
- ZTF photometry: r = 18.71 ± 0.11 (t0+1.91 d); g = 18.38 ± 0.08 (t0+2.07 d).
- GIT photometry at t0+2.489 d: g' = 18.08 ± 0.09; r' = 18.34 ± 0.09 (not corrected for Galactic extinction).
Redshift
What’s special vs typical
- Optical emission is reported (via forced photometry) to precede the first Einstein Probe detection by ~3 hours.
- The transient is reported to be very close to the host nucleus (0.3" offset), suggesting a potentially nuclear origin in the provided context.