The program started in 2011 with the aim to classify all transients that are accessible from Asiago and are bright enough for our telescope/instrumentation. We use mainly the 1.82m Copernico telescope of Cima Ekar and, if not available, the 1.22m Galileo telescope of the Pennar station. A few cases of transients classified by our group with other facilities (eg. TNG) are included in the database.
Transient classification information and spectra (fits format) are made immediately available at our site. The spectra are semi-automatic reduction with archive calibration data. Please keep this in mind when using them.
For SN classification we compare the output of two automatic SN classification codes: Gelato (Harutyunyan et al. 2008, A&A 488, 383) and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).
If you use some of the information posted in these pages please make a reference to the paper Tomasella etal. 2014, A.N. 335, 841.
Discovered by: Pan-STARRS1 (aka PS17ckw)
The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of ASASSN-17fd in Ark481 (AT 2017dfb), discovered during the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN), cf. Atel #10300, and PS17ckw in SDSS J164539.02+013713.1 (AT 2017dgd), discovered by Pan-STARRS1 survey. The observations were performed with the Asiago 1.82 m Copernico Telescope equipped with AFOSC (range 340-820 nm; resolution 1.4 nm).
Survey Name | IAI Name | Discovery date (UT) | Discovery mag | Observation (UT) | Type | z | Notes| ASASSN-17fd | SN 2017dfb |2017-04-19.51 | 16.5 |2017-04-22.02 | SN Ia | 0.025955 | (1) | PS17ckw | SN 2017dgd |2017-04-19.52 | 17.76 |2017-04-22.05 | SN IIb| 0.022 | (2) |
(1) The spectrum is consistent with that of a Type Ia SN 1991T-like events before maximum light, at a redshift 0.0259, as deduced from the position of Halpha emission from the host galaxy (which is in agreement with the redshift of the host galaxy, Ark481 provided by Falco et al. 1999, PASP 111, 438), and in agreement with Cannizzaro et al. 2017 (Atel #10298). The strong Na I doublet absorption at the host galaxy redshift (we measured an EW ~ 2.15 A, which corresponds to a reddening of E(B-V)~0.3 when applying the Turatto et al. 2003 relation, published in ESO ASTROPHYSICS SYMPOSIA "From Twilight to Highlight: The Physics of Supernovae"), suggests large line-of-sight dust absorption.
(2) The red continuum and spectral features are best fitted by the type IIb supernovae before maximum. The spectrum is dominated by deep H-alpha and He-I 587.6 nm absorptions.