Regarding Optical Transients PS1-11xm and PS1-11xn
ATel #3354; A. J. Drake, S. G. Djorgovski, A. A. Mahabal, M. J. Graham, R. Williams, C. Donalek (Caltech); J. Prieto (Carnegie Obs); M. Catelan (PUC); E. Christensen (Gemini Obs); E. C. Beshore, S. M. Larson (LPL/UA).
on 17 May 2011; 03:41 UT
Credential Certification: Andrew J. Drake (ajd@cacr.caltech.edu)
Subjects: Optical, A Comment, Transient
Regarding Smartt et al. (2011, ATEL#3351), we find that transient PS1-11xm was detected in
CSS images taken on 2011-03-15 and 2011-05-13. On both occasions the object was measured
in four images with V ~ 18.8. These values appear consistent with the PS1 magnitude
of i=19.1 observed on 2011-04-19. The lack of a clear brightness variation over this 59 day
observation period is not expected for a type-IIn SN and is unlike that of the probable
ultaluminous type-IIn supernova CSS100217 (Drake et al. 2011a, ApJ, in press).
However, prior observations of the object on 21 nights spanning the period from 2006-02-03
to 2010-06-12 show the object at a brightness consistent with the SDSS r-band magnitude (within
uncertainties). The ~1.8 mag brightness variation is larger than typically observed for
NLS1 (Drake et al. 2011a, Fig 15) and is consistent with the presence of a transient event.
Nevertheless, unlike the normal AGN PS1-1000305 (Kankare et al. 2010, ATel#2716; Drake et al. 2010a, ATEL#2725) and PS1-1000382 (Valenti et al. 2010, ATel#2773; Drake et al. 2010b, ATEL#2784), the CSS
photometric sampling of PS1-11xm is insufficient to constrain possible recent AGN activity.
Transient PS1-11xn (Smartt et al. 2011, ATEL#3351) matches supernova CSS110501:144740+514105 (Drake et al. 2011b, ATel#3324). This object was confirmed by Drake et al. (2011c, ATEL#3340), but incorrectly noted as CSS110501:094825+204333. The observed spectroscopic properties noted in Drake et al. (2011c) are consistent with those given in Smartt et al. (2011).