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Asiago spectroscopic observations of ASASSN-17qy and SN 2017ixv

ATel #11080; M. Berton, S. Chen, S. Ciroi, P. Ochner, E. Congiu, A. Reguitti (Padova University), Y. Cai, A. Pastorello (INAF-OAPd)
on 21 Dec 2017; 16:05 UT
Credential Certification: Marco Berton (marco.berton@unipd.it)

Subjects: Optical, Supernovae, Transient

In the framework of the Asiago Transient Classification Program (see, e.g., Tomasella et al. 2014, AN, 335, 841), we report the spectroscopic classification of ASASSN-17qy in the galaxy 2MASX J06001492-1806013, and confirm the spectroscopic classification of SN 2017ixv in NGC 6796 proposed by R. Leadbeater (via TNS). The candidates were discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014) and Giancarlo Cortini, respectively. The spectra have been obtained with the 1.22m Galileo Telescope of Asiago equipped with a B&C spectrograph (range 330-790 nm; resolution 0.6 nm).

Survey Name    | IAU Name   | Discovery (UT)  | Discovery mag | Observation (UT) | Redshift | Type  | Phase    | Notes 
ASASSN-17qy    | SN 2017iyl | 2017-12-09.45   | 16.7 (V)      | 2017-12-20.98    | 0.027846 | Ia   | +7d       | (1) 
    -          | SN 2017ixv | 2017-12-17.83   | 16.0 (unf.)   | 2017-12-20.75    | 0.007302 | Ic   | after max | (2) 

(1) The spectrum resembles that of the normal Type Ia SN 1999ee (Hamuy et al. 2002, AJ, 124, 417) about one week after the B-band maximum. The velocity of the SN ejecta, as inferred from the position of the minimum of the Si II 635.5 nm feature, is about 10800 km/s. The redshift of the host galaxy is from Huchra et al. 2012, ApJS, 199, 26.

(2) The spectrum resembles that of the broad line Type Ic SNe 2002ap and 1997ef about 10-15 days after light curve peak. A fairly good match is also obtained with that of a normal Type Ic event such as SN 2004ew (Taubenberger et al. 2006, MNRAS, 371, 1459) at a slightly earlier phase (3-5 days after maximum). We also note that a narrow Na I doublet feature is observed in absorption at the host galaxy redshift, with an EW = 3.6 A, suggesting a significant line-of-sight reddening. The redshift of NGC 6798 is from Theureau et al. 1998, A&AS, 130, 333.

Classifications used the GELATO (Harutyunyan et al. 2008, A&A, 488, 383) and SNID (Blondin and Tonry 2007, ApJ, 666, 1024) tools. Calibrated spectra and additional information can be retrieved in the IAU Transient Name Server.