Asiago spectroscopic classification of four SNe

ATel #6899; L. Tomasella, S. Benetti, E. Cappellaro, N. Elias-Rosa, P. Ochner, A. Pastorello, L. Tartaglia, G. Terreran, M. Turatto (INAF OAPd)
on 11 Jan 2015; 06:07 UT
Credential Certification: Lina Tomasella (lina.tomasella@oapd.inaf.it)

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The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic observation of ASASSN-15ak, PSN J09411555+3553174, PSN J12543553-1234186, ASASSN-15ae, MASTER OT J021447.67+481852.6. Targets were supplied by the Astronomy Section of the Rochester Academy of Sciences (arXiv:1103.5165) and/or by the CBAT Transient Objects Confirmation Page (TOCP). The observations were performed with the Asiago 1.82 m Copernico Telescope (+AFOSC; range 340-820 nm; resolution 1.2 nm), which was equipped with the CCD Andor IKON L936.

Name	| Date (UT)	| z	| Type	| Phase	| Notes
ASASSN-15ak	| 20150110.87	| 0.015	| SN Ia-pec	| pre-max	| (1)
MASTER OT J021447.67+481852.6	| 20150110.90	|	| star	|	| (2)
PSN J09411555+3553174	| 20150110.94	| 0.023	| SN Ia	| pre-max	| (3)
PSN J12543553-1234186	| 20150111.12	| 0.015	| SN Ia	| +6d	| (4)
ASASSN-15ae	| 20150111.17	| 0.031	| SN Ia	| +5d	| (5)

(1) Best match with type-Ia pec 91T-like SNe, few days before B-band maximum light. The expansion velocity of ASASSN-15ak, as deduced from the position of the minimum of the Si-II 635.5nm absorption, is around 11000 km/s.

(2) The spectrum shows Balmer absorptions (Hbeta, Hgamma, Hdelta), at rest wavelength, on a strong blue continuum. We note a weak emission component in the red wing of Balmer lines. Weak NaID absorption is also visible.

(3) A good match is found with several normal type-Ia supernovae few days before B-band maximum light. The expansion velocity of PSN J09411555+3553174, as deduced from the position of the minimum of the Si-II 635.5nm absorption, is around 12200 km/s.

(4) The spectrum shows this is a type-Ia SN around one week after B-band maximum light. The expansion velocity of PSN J12543553-1234186, as deduced from the position of the minimum of the Si-II 635.5nm absorption, is around 10800 km/s.

(5) Best match with several type-Ia SNe, about one week after B-band maximum. The expansion velocity of ASASSN-15ae, as deduced from the position of the minimum of the Si-II 635.5nm absorption, is around 11200 km/s. The classification is in agreement with ATel #6897.

Classification was done with GELATO (Harutyunyan et al. 2008, A&A, 488, 383) and SNID (Blondin and Tonry 2007, ApJ, 666, 1024). The Asiago classification spectra are posted at the website http://sngroup.oapd.inaf.it.

Padova Asiago SN group