25 research outputs found
SN 2013ab : A normal type IIP supernova in NGC 5669
We present densely-sampled ultraviolet/optical photometric and low-resolution
optical spectroscopic observations of the type IIP supernova 2013ab in the
nearby (24 Mpc) galaxy NGC 5669, from 2 to 190d after explosion.
Continuous photometric observations, with the cadence of typically a day to one
week, were acquired with the 1-2m class telescopes in the LCOGT network, ARIES
telescopes in India and various other telescopes around the globe. The light
curve and spectra suggest that the SN is a normal type IIP event with a plateau
duration of days with mid plateau absolute visual magnitude of
-16.7, although with a steeper decline during the plateau (0.92 mag 100 d in band) relative to other archetypal SNe of similar brightness.
The velocity profile of SN 2013ab shows striking resemblance with those of SNe
1999em and 2012aw. Following the Rabinak & Waxman (2011) prescription, the
initial temperature evolution of the SN emission allows us to estimate the
progenitor radius to be 800 R, indicating that the SN
originated from a red supergiant star. The distance to the SN host galaxy is
estimated to be 24.3 Mpc from expanding photosphere method (EPM). From our
observations, we estimate that 0.064 M of Ni was synthesized
in the explosion. General relativistic, radiation hydrodynamical modeling of
the SN infers an explosion energy of erg, a progenitor
mass (at the time of explosion) of M and an initial radius
of R.Comment: 22 pages, 18 figures, 5 tables. Accepted for publication in MNRA
Photometric and spectroscopic evolution of the peculiar Type IIn SN 2012ab
We present an extensive ( 1200 d) photometric and spectroscopic
monitoring of the Type IIn supernova (SN) 2012ab. After a rapid initial rise
leading to a bright maximum (M = 19.39 mag), the light curves show a
plateau lasting about 2 months followed by a steep decline up to about 100 d.
Only in the band the decline is constant in the same interval. At later
phases, the light curves remain flatter than the Co decline suggesting
the increasing contribution of the interaction between SN ejecta with
circumstellar material (CSM). Although heavily contaminated by emission lines
of the host galaxy, the early spectral sequence (until 32 d) shows persistent
narrow emissions, indicative of slow unshocked CSM, and the emergence of broad
Balmer lines of hydrogen with P-Cygni profiles over a blue continuum, arising
from a fast expanding SN ejecta. From about 2 months to 1200 d, the
P-Cygni profiles are overcome by intermediate width emissions (FWHM
\kms), produced in the shocked region due to interaction. On the red wing a red
bump appears after 76 d, likely a signature of the onset of interaction of the
receding ejecta with the CSM. The presence of fast material both approaching
and then receding is suggestive that we are observing the SN along the axis of
a jet-like ejection in a cavity devoid of or uninterrupted by CSM in the
innermost regions.Comment: 8 Tables, 17 Figures. Accepted for publication in MNRA
Observations of Type Ia Supernova 2014J for Nearly 900 Days and Constraints on Its Progenitor System
We present extensive ground-based and ()
photometry of the highly reddened, very nearby type Ia supernova (SN Ia) 2014J
in M82, covering the phases from 9 days before to about 900 days after the
-band maximum. SN 2014J is similar to other normal SNe Ia near the maximum
light, but it shows flux excess in the band in the early nebular phase.
This excess flux emission can be due to light scattering by some structures of
circumstellar materials located at a few 10 cm, consistent with a single
degenerate progenitor system or a double degenerate progenitor system with mass
outflows in the final evolution or magnetically driven winds around the binary
system. At t+300 to +500 days past the -band maximum, the light
curve of SN 2014J shows a faster decline relative to the Ni decay. Such
a feature can be attributed to the significant weakening of the emission
features around [Fe III] 4700 and [Fe II] 5200 rather than
the positron escape as previously suggested. Analysis of the images taken
at t600 days confirms that the luminosity of SN 2014J maintains a flat
evolution at the very late phase. Fitting the late-time pseudo-bolometric light
curve with radioactive decay of Ni, Ni and Fe isotopes, we
obtain the mass ratio Ni/Ni as , which is
consistent with the corresponding value predicted from the 2D and 3D
delayed-detonation models. Combined with early-time analysis, we propose that
delayed-detonation through single degenerate scenario is most likely favored
for SN 2014J.Comment: 28 pages, 12 figures. Accepted for publication in Ap
Observations of A Fast-Expanding and UV-Bright Type Ia Supernova SN 2013gs
In this paper, we present extensive optical and ultraviolet (UV) observations
of the type Ia supernova (SN Ia) 2013gs discovered during the Tsinghua-NAOC
Transient Survey. The photometric observations in the optical show that the
light curves of SN 2013gs is similar to that of normal SNe Ia, with an absolute
peak magnitude of = 19.25 0.15 mag and a post-maximum decline
rate m(B) = 1.00 0.05 mag. \emph{Gehrels Swift} UVOT
observations indicate that SN 2013gs shows unusually strong UV emission
(especially in the band) at around the maximum light (M
18.9 mag). The SN is characterized by relatively weak Fe~{\sc ii} {\sc iii}
absorptions at 5000{\AA} in the early spectra and a larger expansion
velocity ( 13,000 km s around the maximum light) than the
normal-velocity SNe Ia. We discuss the relation between the color and
some observables, including Si~{\sc ii} velocity, line strength of Si~{\sc ii}
6355, Fe~{\sc ii}/{\sc iii} lines and (B). Compared to
other fast-expanding SNe Ia, SN 2013gs exhibits Si and Fe absorption lines with
similar strength and bluer color. We briefly discussed the origin of
the observed UV dispersion of SNe Ia.Comment: 31 pages, 10 figures, accepted to publish in Ap
The type IIB supernova 2011DH from a supergiant progenitor
A set of hydrodynamical models based on stellar evolutionary progenitors is used to study the nature of SN 2011DH. Our modeling suggests that a large progenitor star - with R ∼ 200 R⊙ - is needed to reproduce the early light curve (LC) of SN 2011dh. This is consistent with the suggestion that the yellow super-giant star detected at the location of the supernova (SN) in deep pre-explosion images is the progenitor star. From the main peak of the bolometric LC and expansion velocities, we constrain the mass of the ejecta to be ≈2 M⊙, the explosion energy to be E = (6-10) × 1050 erg, and the 56NI mass to be approximately 0.06 M⊙. The progenitor star was composed of a helium core of 3-4 M⊙ and a thin hydrogen-rich envelope of ≈0.1M ⊙ with a main-sequence mass estimated to be in the range of 12-15 M⊙. Our models rule out progenitors with helium-core masses larger than 8 M⊙, which correspond to MZAMS ≳ 25M⊙. This suggests that a single star evolutionary scenario for SN 2011DH is unlikely.Facultad de Ciencias Astronómicas y Geofísica
The Type IIb Supernova 2011dh from a Supergiant Progenitor
A set of hydrodynamical models based on stellar evolutionary progenitors is
used to study the nature of SN 2011dh. Our modeling suggests that a large
progenitor star ---with R ~200 Rsun---, is needed to reproduce the early light
curve of SN 2011dh. This is consistent with the suggestion that the yellow
super-giant star detected at the location of the SN in deep pre-explosion
images is the progenitor star. From the main peak of the bolometric light curve
and expansion velocities we constrain the mass of the ejecta to be ~2 Msun, the
explosion energy to be E= 6-10 x 10^50 erg, and the 56Ni mass to be
approximately 0.06 Msun. The progenitor star was composed of a helium core of 3
to 4 Msun and a thin hydrogen-rich envelope of ~0.1 M_sun with a main sequence
mass estimated to be in the range of 12--15 Msun. Our models rule out
progenitors with helium-core masses larger than 8 Msun, which correspond to
M_ZAMS > 25 Msun. This suggests that a single star evolutionary scenario for SN
2011dh is unlikely.Comment: 20 pages with 12 figures. Submitted to The Astrophysical Journal on
24 May 2012 and accepted on 17 July 201
Dust Environment Model of the Interstellar Comet 2I/Borisov
2I/Borisov is the first interstellar comet discovered on 2019 August 30, and it soon showed a coma and a dust tail. This study reports the results of images obtained at the Telescopio Nazionale Galileo telescope, on La Palma - Canary Islands, in 2019 November and December. The images have been obtained with the R filter in order to apply our dust tail model. The model has been applied to the comet 67P/Churyumov-Gerasimenko and compared to the Rosetta dust measurements showing a very good agreement. It has been applied to the comet 2I/Borisov, using almost the same parameters, obtaining a dust environment similar to that of 67P/Churyumov-Gerasimenko, suggesting that the activity may be very similar. The dust tail analysis provided a dust-loss rate Qd ≍ 35 kg s-1 in 2019 November and Qd ≍ 30 kg s-1 in 2019 December
Early Spectroscopy and Dense Circumstellar Medium Interaction in SN~2023ixf
We present the optical spectroscopic evolution of SN~2023ixf seen in
sub-night cadence spectra from 1.18 to 14 days after explosion. We identify
high-ionization emission features, signatures of interaction with material
surrounding the progenitor star, that fade over the first 7 days, with rapid
evolution between spectra observed within the same night. We compare the
emission lines present and their relative strength to those of other supernovae
with early interaction, finding a close match to SN~2020pni and SN~2017ahn in
the first spectrum and SN~2014G at later epochs. To physically interpret our
observations we compare them to CMFGEN models with confined, dense
circumstellar material around a red supergiant progenitor from the literature.
We find that very few models reproduce the blended \NC{} emission lines
observed in the first few spectra and their rapid disappearance thereafter,
making this a unique diagnostic. From the best models, we find a mass-loss rate
of \mlunit{}, which far exceeds the mass-loss rate for any
steady wind, especially for a red supergiant in the initial mass range of the
detected progenitor. These mass-loss rates are, however, similar to rates
inferred for other supernovae with early circumstellar interaction. Using the
phase when the narrow emission features disappear, we calculate an outer dense
radius of circumstellar material and a mean circumstellar material density
of . This is consistent with the
lower limit on the outer radius of the circumstellar material we calculate from
the peak \Halpha{} emission flux, .Comment: Submitted to ApJ