| 1. |
- Clark, Peter, et al.
(författare)
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LSQ13ddu : a rapidly evolving stripped-envelope supernova with early circumstellar interaction signatures
- 2020
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 492:2, s. 2208-2228
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the rapidly evolving and unusual supernova LSQ13ddu, discovered by the La Silla-QUEST survey. LSQ13ddu displayed a rapid rise of just 4.8 +/- 0.9 d to reach a peak brightness of -19.70 +/- 0.02 mag in the LSQgr band. Early spectra of LSQ13ddu showed the presence of weak and narrow He I features arising from interaction with circumstellar material (CSM). These interaction signatures weakened quickly, with broad features consistent with those seen in stripped-envelope SNe becoming dominant around two weeks after maximum. The narrow He I velocities are consistent with the wind velocities of luminous blue variables but its spectra lack the typically seen hydrogen features. The fast and bright early light curve is inconsistent with radioactive Ni-56 powering but can be explained through a combination of CSM interaction and an underlying Ni-56 decay component that dominates the later time behaviour of LSQ13ddu. Based on the strength of the underlying broad features, LSQ13ddu appears deficient in He compared to standard SNe Ib.
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| 2. |
- Maguire, Kate, et al.
(författare)
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Tidal Disruptions of White Dwarfs : Theoretical Models and Observational Prospects
- 2020
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 216:3
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Forskningsöversikt (refereegranskat)abstract
- White dwarf stars that enter the tidal radius of black holes with masses less than or similar to 10(5) M-circle dot are doomed to be ripped apart by tidal forces. Black holes in this mass range between stellar black holes and supermassive black holes have not been conclusively identified so the detection of a tidal disruption of a white dwarf would provide clear evidence for the existence of intermediate-mass black holes. In this review, we present a theoretical and observational overview of the transient events that result from the tidal disruptions of white dwarfs by intermediate-mass black holes. This includes discussion of the latest simulations and predicted properties, the results of observational searches, as well as a summary of the potential for gravitational wave emission to be detected with upcoming missions.
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| 3. |
- Tomasella, Lina, et al.
(författare)
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Observations of the low-luminosity Type Iax supernova 2019gsc : a fainter clone of SN 2008ha?
- 2020
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 496:2, s. 1132-1143
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Tidskriftsartikel (refereegranskat)abstract
- We present optical photometric and spectroscopic observations of the faint-and-fast evolving Type Iax supernova (SN) 2019gsc, extending from the time of g-band maximum until about 50 d post-maximum, when the object faded to an apparent r-band magnitude m(r )= 22.48 +/- 0.11 mag. SN 2019gsc reached a peak luminosity of only M-g = -13.58 +/- 0.15 mag, and is characterized with a post-maximum decline rate Delta m(15)(g) = 1.08 +/- 0.14 mag. These light curve parameters are comparable to those measured for SN 2008ha of M-g = -13.89 +/- 0.14 mag at peak and Delta m(15)(g) =1.80 +/- 0.03 mag. The spectral features of SN 2019gsc also resemble those of SN 2008ha at similar phases. This includes both the extremely low ejecta velocity at maximum, similar to 3000 km s(-1) and at late-time (phase +54 d) strong forbidden iron and cobalt lines as well as both forbidden and permitted calcium features. Furthermore, akin to SN 2008ha, the bolometric light curve of SN 2019gsc is consistent with the production of approximate to 0.003 +/- 0.001 M-circle dot of Ni-56. The explosion parameters, M-ej approximate to 0.13 M-circle dot and E-k approximate to 12 x 10(48) erg, are also similar to those inferred for SN 2008ha. We estimate a subsolar oxygen abundance for the host galaxy of SN 2019gsc (12 + log(10)(O/H) =8.10 +/- 0.18 dex), consistent with the equally metal-poor environment of SN 2008ha. Altogether, our data set for SN 2019gsc indicates that this is a member of a small but growing group of extreme SN Iax that includes SN 2008ha and SN 2010ae.
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