[vsnet-alert 20703] Gaia17amf - likely dwarf nova

[Denis Denisenko]

On Feb. 24th Gaia Science Alert Team has published an object in Lupus
Gaia17amf (aka AT 2017bjs) observed in outburst a month ago, on Jan. 24:

http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia17amf/
declining, hostless transient
14 33 03.20 -52 14 47.3

20170124.8535  16.80  Gaia
20170220.0795  18.07  Gaia
20170220.1535  17.85  Gaia

The entry at TNS https://wis-tns.weizmann.ac.il/object/2017bjs states the
last non-detection was only 106 minutes (!!!) before the discovery image.

20170124.7780  <21.5  Gaia last non-detection

I have checked DSS plates and found a previous outburst on the 1979-07-06
infrared SERC-I plate. The star is present in GSC2.3.2 Catalogue as GSC2.3
S95B108024 with Nmag=16.07. Nothing is visible on other plates, including
an earlier IR plate on 1979-05-15. Animation of 1979 May 15 and July 06
plates is uploaded to
http://scan.sai.msu.ru/~denis/Gaia17amf-DSS-IR-1979-anim.gif

Object appears to be a dwarf nova with an amplitude of at least 5.5m
(16.1-<21.5). However, the last non-detection looks strange. Outburst by 5m
from 18:40 UT to 20:26 UT on Jan. 24th sounds extremely unlikely. Deep
eclipse or misprint?

Denis Denisenko