Supernova 2010ev: A reddened high velocity gradient type Ia supernova^⋆

¹ Millennium Institute of Astrophysics, Casilla 36-D, Santiago Chile
e-mail: cgutierr@das.uchile.cl
² Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
³ European Southern Observatory, Alonso de Córdova 3107, Casilla 19 001, Santiago 19, Chile
⁴ Instituto de Astrofísica de La Plata (IALP, CONICET), 1467 La Plata Argentina
⁵ Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. República 252, Santiago, Chile
⁶ Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena, Chile
⁷ Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
⁸ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
⁹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁰ INAF − Osservatorio Astrofisico di Catania, Via Santa Sofia, 78, 95123, Catania, Italy
¹¹ University of North Carolina at Chapel Hill, Campus Box 3255, Chapel Hill, NC 27599-3255, USA

Received: 21 August 2015
Accepted: 1 February 2016

Abstract

Aims. We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev.

Methods. We obtain and analyze multiband optical light curves and optical/near-infrared spectroscopy at low and medium resolution spanning −7 days to +300 days from the B-band maximum.

Results. A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of Δm₁₅(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B − V) = 0.25 ± 0.05 and a reddening law of R_v = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si  iiλ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with v̇_Si = 164 ± 7 km s^-1 d^-1. The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the [Fe ii]λ7155 and [Ni ii]λ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions.