[vsnet-alert 25575] ASASSN-21dy (12.5m) - outburst of 1RXS J055902.4-114236

[Denis Denisenko d.v.denisenko@gmail.com via vsnet-alert]

ASAS-SN has reported a bright rising transient ASASSN-21dy = AT 2021gsq at
the position 05 59 03.68 -11 42 43.6 (north-eastern Lepus).
TNS entry: https://www.wis-tns.org/object/2021gsq

ASAS-SN light curve for the last 20 days (Shappee et al., 2014; Kochanek et
al., 2017):
https://asas-sn.osu.edu/sky-patrol/coordinate/574d4ffe-239f-46ea-b56e-2b67f3b3e767

ASASSN-21dy
  20210318.1051  >171g   ASAS-SN
  20210318.7692  16.36o  ATLAS (Tonry et al., 2018)
  20210318.7966  16.40o  ATLAS (Tonry et al., 2018)
  20210320.0920  13.36g  ASAS-SN
  20210320.0945  13.34g  ASAS-SN
  20210321.0998  12.50g  ASAS-SN
  20210321.1022  12.49g  ASAS-SN

The object at quiescence is likely identical to the 19-ish magnitude star
formally 0.7" away in Gaia EDR3:
05 59 03.72 -11 42 43.1  Plx=1.89+/-0.49 mas pmRA=-0.74+/-0.37
pmDE=-10.71+/-0.38 mas/yr
Gmag=19.98+/-0.01 BP=20.36+/-0.08 RP=19.45+/-0.05 BP-RP=0.914

IDs from other catalogs:
USNO-A2.0 0750-01701265 (B=18.8 R=18.8)
USNO-B1.0 0782-0100700 (B1=19.99 R1=18.70 B2=20.51 R2=18.63 I=18.73)
1RXS J055902.4-114236  Flux=0.0208+/-0.0078 cnts/s HR1=0.48+/-0.35
HR2=0.33+/-0.41
(faint ROSAT X-ray source with 13" error circle formally 20" away)

Outburst amplitude is about 7 magnitudes.

Denis Denisenko