The Angstrom Project: two new microlensing/nova transients
ATel #1857; Eamonn Kerins (University of Manchester)
on 30 Nov 2008; 20:16 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Eamonn Kerins (Eamonn.Kerins@manchester.ac.uk)
Subjects: Optical, Microlensing Event, Nova
We report the discovery of two new optical transients in M31 by the Angstrom Project M31 bulge
microlensing survey using the Liverpool Telescope (La Palma). These
transients were discovered
using difference imaging techniques by the Angstrom
Project Alert System (APAS) in a series of
Sloan i'-band images of the bulge of M31.
ANG-08B-M31-04 is located at RA=00:42:57.3 Dec=+41:15:41.1 (J2000), 148.''05
East and 33.''52
South of the core of M31. Periodic light-curve behaviour is seen throughout
the previous four
Angstrom observing seasons, consistent with a long-period variable at or
close to the position of
this event. However a stronger and sharper peak in the i' band was observed
to reach a maximum of
mi=20.2±0.1 (provisional) on November 24.885 2008. The
light-curve of this object suggests that it
is likely to be an ongoing nova or possibly an exotic microlensing system.
ANG-08B-M31-05 is located at RA=00:42:59.0 Dec=+41:17:15.5 (J2000), 164.''06
East and
72.''06 North of the core of M31. Periodic variation has been observed at
this position through the
past four Angstrom observing seasons. However the current rise is
substantially stronger than
previous variations. This event was observed with a magnitude of
mi=20.4±0.1 (provisional) as of
November 24.885. The current behaviour is consistent with microlensing with
a full-width half-maximum time-scale of 30.43±1.89 days and a predicted peak
occurring at MJD=54793.28±0.92
days. Follow-up observations of this event are encouraged.
More information, including light-curves and imaging data, is available from
the Angstrom Project
Alert
page.
The Angstrom Project Website
