Spectroscopic Classification of DES Supernova Candidates with Magellan

ATel #6589; P. Challis, A. Avelino, R. P. Kirshner, K. Mandel (Harvard-Smithsonian Center for Astrophysics); E. Ahn, D. A. Finley, J. Frieman, J. Marriner, W. Wester (Fermilab); G. Aldering, A. G. Kim, R. C. Thomas (Lawrence Berkeley National Laboratory); K. Barbary, J. S. Bloom, D. Goldstein, P. Nugent, S. Perlmutter (Lawrence Berkeley National Laboratory + University of California, Berkeley); R. J. Foley (University of Illinois); F. J. Castander (ICE, IEEC/CSIC, Barcelona); S. Desai, K. Paech (Ludwig Maximilians University, Munich); R. C. Smith (NOAO/CTIO); M. Schubnell (University of Michigan); R. Kessler, D. Scolnic (University of Chicago); R. A. Covarrubias (University of Illinois / NCSA); R. C. Wolf, J. A. Fischer, J.-L. Fischer, L. Gladney, M. March, M. Sako (University of Pennsylvania); P. J. Brown, K. Krisciunas, N. Suntzeff (Texas A&M University); C. D'Andrea, R. Nichol, A. Papadopoulos (University of Portsmouth); M. Smith, M. Sullivan (University of Southampton); R. Maartens (University of the Western Cape); R. Gupta, E. Kovacs, S. Kuhlmann, H. Spinka (Argonne National Laboratory)
on 17 Oct 2014; 16:34 UT
Credential Certification: Chris D'Andrea (chris.dandrea@port.ac.uk)

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We report optical spectroscopy of supernova candidates discovered by the Dark Energy Survey (ATel #4668). The spectra (420-950 nm) were obtained using LDSS-3C on the 6.5m Clay telescope at the Las Campanas Observatory on Sept 23,24, 2014. Object classification was performed using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

 
Name       |  RA (J2000) |  Dec (J2000) | Disc.       |Disc.  | Spectrum    |Redshift|Type      |Phase |Notes 
                                        | Date (UT)   |Mag (r)| Date (UT)   |        |          |      |  
DES14E2f   | 00 42 01.13 | -43 31 27.7  | 2014 Aug 17 | 21.6  | 2014 Sep 23 |0.349   |galaxy    |      |  
DES14E2aqu | 00 40 10.75 | -44 01 48.8  | 2014 Sep 11 | 23.0  | 2014 Sep 23 |0.193   |blue cont.|      | 1 
DES14X2cy  | 02 22 51.25 | -07 11 18.3  | 2014 Aug 17 | 22.1  | 2014 Sep 23 |0.232   |II        |+200  | 2 
DES14X3aeb | 02 24 24.61 | -04 40 29.7  | 2014 Sep 02 | 21.2  | 2014 Sep 23 |0.314   |Ia        |+13   | 
DES14S1td  | 02 52 22.94 | +00 37 20.0  | 2014 Aug 20 | 22.3  | 2014 Sep 23 |0.170   |galaxy    |      |   
DES14S1aot | 02 51 12.85 | -00 40 08.8  | 2014 Sep 02 | 22.9  | 2014 Sep 23 |0.364   |Ia        |0     |   
DES14S1aow | 02 50 35.72 | +00 56 16.6  | 2014 Sep 02 | 23.1  | 2014 Sep 23 |0.472   |Ia        |0     | 
DES14C1es  | 03 36 41.40 | -27 50 24.0  | 2014 Aug 17 | 20.9  | 2014 Sep 23 |0.219   |Ia        |+26   |   
DES14C2pw  | 03 38 02.38 | -29 19 49.2  | 2014 Aug 20 | 21.2  | 2014 Sep 23 |0.101   |Ia        |+80   |   
DES14C2apq | 03 40 21.49 | -29 02 54.9  | 2014 Sep 03 | 23.3  | 2014 Sep 23 |0.303   |II        |      | 3 
DES14C3aol | 03 30 09.97 | -28 42 27.4  | 2014 Sep 02 | 21.7  | 2014 Sep 23 |0.075   |II        |+25   |   

Notes:

(1) DES14E2aqu displays a blue continuum consistent with a young core-collapse SN. At z = 0.193, it was discovered at M ~ -17.0 mag.

(2) DES14X2cy is an old SN II. SNID matches include the SN IIn 1998S at +200 days and SN IIL 1979C at +80 days. On examination of Year 1 DES data, we detect the SN in the last images of our first campaign, Feb. 9, 2014. It is detected in all 4 griz filters. This implies that the SN was at about 185 days (in the rest frame) after explosion at the time the Magellan spectrum was obtained.

(3) DES14C2apq appears to be a SN II, with the best SNID matches consistent with the SN IIb "hypernova" 2003bg, although there are no obvious He lines. There are some, lower-quality matches with SNe Ic-BL as well. The absorption feature at ~6240 A in the rest frame, if H alpha, would be at about -15,000 km/s, consistent with SN 2003bg. If this feature were Si II, as is the case in SNe Ic-BL, it would be at only -5300 km/s, making such an identification unlikely.