16 research outputs found
How much radioactive nickel does ASASSN-15lh require?
The discovery of the most luminous supernova ASASSN-15lh triggered a
shock-wave in the supernova community. The three possible mechanisms proposed
for the majority of other superluminous supernovae do not produce a realistic
physical model for this particular supernova. In the present study we show the
limiting luminosity available from a nickel-powered pair-instability supernova.
We computed a few exotic nickel-powered explosions with a total mass of nickel
up to 1500 solar masses. We used the hydrostatic configurations prepared with
the GENEVA and MESA codes, and the STELLA radiative-transfer code for following
the explosion of these models. We show that 1500 solar masses of radioactive
nickel is needed to power a luminosity of 2x10^45 erg/s. The resulting light
curve is very broad and incompatible with the shorter ASASSN-15lh time-scale.
This rules out a nickel-powered origin of ASASSN-15lh. In addition, we derive a
simple peak luminosity - nickel mass relation from our data, which may serve to
estimate of nickel mass from observed peak luminosities.Comment: accepted for publication in MNRAS Letter
Near-Infrared and Optical Observations of Type Ic SN 2021krf: Luminous Late-time Emission and Dust Formation
We present near-infrared (NIR) and optical observations of the Type Ic
supernova (SN Ic) SN 2021krf obtained between days 13 and 259 at several
ground-based telescopes. The NIR spectrum at day 68 exhibits a rising -band
continuum flux density longward of 2.0 m, and a late-time optical
spectrum at day 259 shows strong [O I] 6300 and 6364 \r{A} emission-line
asymmetry, both indicating the presence of dust, likely formed in the SN
ejecta. We estimate a carbon-grain dust mass of 2 10
M and a dust temperature of 900 - 1200 K associated with this
rising continuum and suggest the dust has formed in SN ejecta. Utilizing the
one-dimensional multigroup radiation hydrodynamics code STELLA, we present two
degenerate progenitor solutions for SN 2021krf, characterized by C-O star
masses of 3.93 and 5.74 M, but with the same best-fit Ni mass
of 0.11 M for early times (0-70 days). At late times (70-300 days),
optical light curves of SN 2021krf decline substantially more slowly than that
expected from Co radioactive decay. Lack of H and He lines in the
late-time SN spectrum suggests the absence of significant interaction of the
ejecta with the circumstellar medium. We reproduce the entire bolometric light
curve with a combination of radioactive decay and an additional powering source
in the form of a central engine of a millisecond pulsar with a magnetic field
smaller than that of a typical magnetar.Comment: Accepted for publication in ApJ, 27 pages, 21 figures, 6 tables.
Previous arXiv submission (arXiv:2211.00205) replaced after acceptanc
Type Ib/Ic Supernovae: Effect of Nickel Mixing on the Early-time Color Evolution and Implications for the Progenitors
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