ASAS-SN Discovery of two bright CVs

ATel #5102; J. L. Prieto (Princeton), S. Villanueva, M. Fausnaugh, B. J. Shappee, K. Z. Stanek, C. S. Kochanek, J. Jencson, A. Talabere, J. F. Beacom (Ohio State), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), M. Dubberley, M. Elphick, S. Foale, E. Hawkins, D. Mullens, W. Rosing, R. Ross, Z. Walker (Las Cumbres Observatory)
on 4 Jun 2013; 15:25 UT
Credential Certification: Jose L. Prieto (jose@obs.carnegiescience.edu)

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During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"; ATel #4987, #4999, #5010, #5052, #5082), using data from the double 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered two new transients:

  
Object       RA (J2000)   DEC (J2000)     Disc. UT Date     Approx. Disc. V mag  
ASASSN-13al  19:32:06.63  +67:27:41.6     2013 June 1.47          15.2     
ASASSN-13am  22:11:59.05  +30:28:35.2     2013 June 4.52          15.3 

ASASSN-13al was present in images obtained 2013 UT June 1.47 but undetected (V > 17) on 2013 UT May 25 and earlier. Vizier reveals an optical source with B = 20.2-20.8 detected 1.6" from our ASAS-SN position in the USNO-B1 catalog. Images obtained by S. Villanueva and M. Fausnaugh with the MDM 2.4m telescope on 2013 Jun 2.45 confirmed the detection of the source. An optical spectrum obtained on June 4.3 with the APO 3.5m telescope (+DIS) shows almost no continuum with Balmer lines in emission (Halpha EW = 34 Angstroms, FWHM = 1600 km/s). The acquisition images obtained with APO showed that the source had faded significantly by June 4. ASASSN-13al is a CV in outburst past peak.

ASASSN-13am was present in images obtained 2013 UT June 4.52 but undetected (V > 17) on 2013 UT May 30 and earlier. SDSS DR9 reveals a blue star with g=21.89 +/- 0.06, r=21.90 +/- 0.08 detected at 0.2" from the position of the transient. ASASSN-13am is most likely a CV in outburst.