Swift Transient in M31: Limits on Archival Optical Flares
ATel #6178; S. G. Djorgovski, A. J. Drake, A. A. Mahabal, and the CRTS survey team
on 28 May 2014; 06:57 UT
Credential Certification: S. George Djorgovski (george@astro.caltech.edu)
Subjects: Optical, Globular Cluster, Transient
Archival photometry of the M31 globular cluster G108 (Bo 45), associated with the transient reported by the Swift team (Barthelmy et al., GCN 16332), from the Catalina Real-Time Transient Survey (CRTS), spanning ~ 200 measurements over a period of ~ 8 years (from 04 Dec 2005 UT to 23 Sep 2013 UT) shows no flaring with an amplitude greater than 10% of the cluster luminosity.
Assuming a distance modulus of 24.45 mag (from NED), and the observed V band magnitude of the cluster of 15.45 mag from CRTS, the cluster luminosity is ~ 3.3e+5 solar luminosities, and thus the upper limit on the amplitude of any flares is ~ 3.3e+4 solar luminosities, broadly comparable to the peak luminosities of classical novae.
CRTS light curve can be downloaded from our public data server, at: http://nesssi.cacr.caltech.edu/cgi-bin/getcssconedb_id.cgi
entering the object ID 1140003077374.
CRTS survey
