GRB 201021B MAXI/GSC detection

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 2020-10-21T16:18:55UT . Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (3.592 deg, -63.535 deg) = (00 14 22, -63 32 05) (J2000) with a 90% C.L. statistical error of 0.24 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 212 +- 25 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 14:46 and in the next transit at 17:51 UT with an upper limit of 20 mCrab for each.