CRTS observations of recent PS1 transients
ATel #2784; A. J. Drake, A. A. Mahabal, S. G. Djorgovski, M. J. Graham, R. Williams (Caltech); J. Prieto (OCIW); M. Catelan (PUC); E. Christensen (Gemini Observatory); E. C. Beshore, S. M. Larson (LPL/UA)
on 9 Aug 2010; 17:48 UT
Credential Certification: Andrew J. Drake (ajd@cacr.caltech.edu)
Subjects: Optical, A Comment, AGN, Supernovae
Referred to by ATel #: 3354
Valenti et al. (2010, ATel#2773) recently reported the discovery of an AGN outburst (PS1-1000382) detected in PS1 taken data on June 12.23 UT with magnitude g=17.9. The redshift of the AGN is given by Valenti et al. (2010) as z=0.435 and host galaxy SDSS J160414.08+091354.0.
We have extracted the five year archival CSS/CRTS lightcurve at the location of
PS1-1000382
and SDSS DR7 data.
The CSS lightcurve for this object shows that the AGN is declining from maximum brightness which
occurred in mid-2009. SDSS data gives the following magnitudes:
u=20.6, g=20.1, r=19.6, i=19.1, z=18.7, on observation date = 2003-06-22
u=18.6, g=18.2, r=18.2, i=18.1, z=17.9, on observation date = 2005-05-13
The 2005-05-13 SDSS magnitudes are consistent with those measured by CSS on 2005-05-19 (within
transformation uncertainties). Clearly the 2005 SDSS g-band magnitude is close to the PS1
"outburst" magnitude. The combination of SDSS and CSS data suggest that PS1-1000382, like PS1-1000305
(see Drake et al. 2010 ),
is due to long-timescale variability rather than an AGN outburst event.
Valenti et al. (2010) note PS1-1000384 as another AGN outburst event discovered by PS1 at r=19.34
as measured on June 6.60. We find this object exhibits no significant variation from V~19.5 on 5 nights of CSS observations taken between 2008-06-14 and 2010-06-20.
Lastly, Valenti et al. (2010) report the discovery of type IIp supernova PS1-1000383 on June 3.54 2010
(2 months past explosion). We confirm that an outburst is clearly seen in CSS data taken on May 18.38 UT and at 3-sigma significance on Apr 11.42 UT.