Abstract:
Optical and NIR observations of the Type Ia supernova SN 2014J in M82 are presented. The
observed light curves are found to be similar to normal Type Ia supernovae (SNe Ia), with
a decline rate parameter
m
15
(
B
)
=
1.08
±
0.03. The supernova reached
B
-band maximum
on JD 2456690.14, at an apparent magnitude
m
B
(max)
=
11.94. The optical spectra show a
red continuum with deep interstellar Na
I
absorption, but otherwise resemble those of normal
SNe Ia. The Si
II
λ
6355 feature indicates a velocity of
∼
12 000 km s
−
1
at
B
-band maximum,
which places SN 2014J at the border of the normal velocity and high velocity group of SNe Ia.
The velocity evolution of SN 2014J places it in the Low Velocity Gradient subclass, whereas
the equivalent widths of Si
II
features near
B
-band maximum place it at the border of the core
normal and Broad Line subclasses of SNe Ia. An analytic model fit to the bolometric light
curve indicates that a total of
∼
1.3 M
was ejected in the explosion, and the ejected
56
Ni mass
M
Ni
∼
0.6 M
. The low [Fe
III
]
λ
4701 to [Fe
II
]
λ
5200 ratio in the nebular spectra of SN 2014J
hints towards clumpiness in the ejecta. Optical broad-band, linear polarimetric observations of
SN 2014J obtained on four epochs indicate an almost constant polarization (
P
R
∼
2.7 per cent;
θ
∼
37
◦
), which suggests that the polarization signal is of interstellar origin.
