[vsnet-grb-info 3158] OT 060420: CONCAM detection of a candidate new magnitude 5 optical

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4995
SUBJECT: OT 060420: CONCAM detection of a candidate new magnitude 5 optical
DATE:    06/04/21 23:06:32 GMT
FROM:    Robert Nemiroff at Michigan Tech.  <nemiroff at mtu.edu>

R. J. Nemiroff and L. Shamir (Michigan 
Tech) report on behalf of the Night Sky 
Live CONCAM Project

A magnitude 5 (five) optical transient 
(OT) of unknown origin appears on three 
successive frames from the Cerro Pachon 
CONCAM in Chile and concurrently on two 
successive frames from the Canary Island 
CONCAM in Spain.   We estimate the 
broadband CONCAM unfiltered CCD 
magnitude at about 4.5 at its brightest.

The approximate location of the 
transient is
RA:   13 38
Dec: -12 25
with an accuracy of about 0.5 degrees.

The times and brightness estimates 
(visually estimated and assumed accurate 
to about one magnitude) for the optical 
transient are:

UT frame start: 00h 19m 43s
Estimated magnitude: 5.0
Exposure: 180 sec
CONCAM location: Cerro Pachon, Chile
JPG image: 
http://nightskylive.net/cp/cp060420/cp060420ut001943p.jpg
FITS image: 
http://nightskylive.net/cp/cp060420/cp060420ut001943p.fits
X,Y location of OT on FITS image: (182, 514)

UT frame start: 00h 23m 39s
Estimated magnitude: 4.5
Exposure: 180 sec
CONCAM location: Cerro Pachon, Chile
JPG image: 
http://nightskylive.net/cp/cp060420/cp060420ut002339p.jpg
FITS image: 
http://nightskylive.net/cp/cp060420/cp060420ut002339p.fits
X,Y location of OT on FITS image: (187, 518)

UT frame start: 00h 27m 36s
Estimated magnitude: 5.0
Exposure: 180 sec
CONCAM location: Cerro Pachon, Chile
JPG image: 
http://nightskylive.net/cp/cp060420/cp060420ut002736p.jpg
FITS image: 
http://nightskylive.net/cp/cp060420/cp060420ut002736p.fits
X,Y location of OT on FITS image: (190, 520)

UT frame start: 00h 19m 43s
Estimated magnitude: 5.0
Exposure: 180 sec
CONCAM location: Canary Islands, Spain
JPG image: 
http://nightskylive.net/ci/ci060420/ci060420ut001943p.jpg
FITS image: 
http://nightskylive.net/ci/ci060420/ci060420ut001943p.fits
X,Y location of OT on FITS image: (429, 258)

UT frame start: 00h 23m 41s
Estimated magnitude: 4.5
Exposure: 180 sec
CONCAM location: Canary Islands, Spain
JPG image: 
http://nightskylive.net/ci/ci060420/ci060420ut002341p.jpg
FITS image: 
http://nightskylive.net/ci/ci060420/ci060420ut002341p.fits
X,Y location of OT on FITS image: (435, 257)

The quality of the Canary Island CONCAM 
frames is marginal but, we believe, good 
enough to bolster the OT interpretation. 
  This is the first time the Night Sky 
Live / CONCAM project is reporting such 
a transient and so we do advise caution 
about its interpretation as an 
astronomical source.  However, the Night 
Sky Live project has had CONCAMs running 
since mid-2000 and has never before had 
cause to report any brief optical 
transient like this: this OT is seen on 
more than one frame, by more than one 
CONCAM, and appears to rotate with the 
sky.   The OT was found initially by 
data mining software.  Given the 
approximate 10,000 kilometer distance 
between the two CONCAMs, the lack of 
obvious parallax of the OT yields a 
minimum OT distance estimate of about 
300,000 kilometers.

All numbers and estimates are 
preliminary at this time.  Future 
observations attempting to discern the 
nature of the OT 060420 are encouraged.

This message may be cited.