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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
Password Certification: Andrew J. Drake (ajd@cacr.caltech.edu)

Subjects: Optical, A Comment, AGN, Nova, Supernova

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.


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