The slowly declining type Ia supernova 2008fv and the near-infrared second maximum^⋆

¹ INAF-Osservatorio Astronomico di Teramo, via M. Maggini s.n.c., 64100 Teramo, Italy
e-mail: biscardi@oa-teramo.inaf.it
² Dipartimento di Fisica – Università di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome, Italy
³ Central Astronomical Observatory at Pulkovo, Pulkovskoe Shosse 65, 196140 St. Petersburg, Russia

Received: 25 January 2010
Accepted: 12 October 2011

Abstract

Aims. We present optical and near-infrared (NIR) photometry of supernova (SN) 2008fv and a brief investigation of SN type Ia to search for possible correlations between the properties of NIR light curves and the optical decline rate.

Methods. We analyse our BVRI and JHK observations to derive light curves (LCs), colour curves, and the bolometric behaviour of SN 2008fv. Data range from about five days before to two months after maximum. We also collect a database of the main characteristics of NIR LCs of SNe Ia available in literature.

Results. We find close similarities between the observed LCs of the SN event studied here and SN 2000E. SN 2008fv is a slow-declining SNe Ia with a post-maximum decline of Δm_15,B = 0.96  ±  0.08 mag and a B-band maximum luminosity of M_B,0 =  −19.40    ±    0.1 mag, close to the value of normal SNe Ia. The optical and NIR data allow us to constrain the host galaxy reddening of NGC 3147, E(B − V) = 0.22  ±  0.05 mag and its distance μ = 33.2  ±  0.1 mag. Furthermore, we derive a synthesized ⁵⁶Ni mass of about 0.7 M_⊙, by using the well-known relation between the maximum luminosity of the uvoir bolometric light curve and the initial content of ⁵⁶Ni. We investigate the correlation between the NIR characteristics of LCs and optical properties by collecting data of a sample of 40 SNe. We derive quantitative relationships involving the epoch of the secondary maximum in the JHK bands and the decline rate Δm₁₅(B). Further, we find no correlations between Δm₁₅ measured in the JHK bands and the optical Δm₁₅(B). In contrast, quite evident correlations with the Δm₁₅(B) and Δm₄₀(J)/Δm₁₅(H).