scholarly journals Neutrino and gravitational wave signal of a delayed-detonation model of type Ia supernovae

2015 ◽  
Vol 92 (12) ◽  
Author(s):  
Ivo R. Seitenzahl ◽  
Matthias Herzog ◽  
Ashley J. Ruiter ◽  
Kai Marquardt ◽  
Sebastian T. Ohlmann ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Type Ia Supernovae ◽  
Wave Signal ◽  
Type Ia ◽  
Ia Supernovae ◽  
Detonation Model

scholarly journals Linear spectropolarimetry of 35 Type Ia supernovae with VLT/FORS: an analysis of the Si ii line polarization

2019 ◽  
Vol 490 (1) ◽  
pp. 578-599 ◽  
Author(s):  
Aleksandar Cikota ◽  
Ferdinando Patat ◽  
Lifan Wang ◽  
J Craig Wheeler ◽  
Mattia Bulla ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Numerical Predictions ◽  
Very Large Telescope ◽  
Type Ia ◽  
Supernova Explosions ◽  
Statistical Sample ◽  
Ia Supernovae ◽  
Low Dispersion ◽  
Detonation Model

ABSTRACT Spectropolarimetry enables us to measure the geometry and chemical structure of the ejecta in supernova explosions, which is fundamental for the understanding of their explosion mechanism(s) and progenitor systems. We collected archival data of 35 Type Ia supernovae (SNe Ia), observed with Focal Reducer and Low-Dispersion Spectrograph (FORS) on the Very Large Telescope at 127 epochs in total. We examined the polarization of the Si ii λ6355 Å line ($p_{\rm Si\, \small {II}}$) as a function of time, which is seen to peak at a range of various polarization degrees and epochs relative to maximum brightness. We reproduced the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship identified in a previous study, and show that subluminous and transitional objects display polarization values below the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship for normal SNe Ia. We found a statistically significant linear relationship between the polarization of the Si ii λ6355 Å line before maximum brightness and the Si ii line velocity and suggest that this, along with the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship, may be explained in the context of a delayed-detonation model. In contrast, we compared our observations to numerical predictions in the $\Delta m_{15}\!-\!v_{\rm Si\, \small {II}}$ plane and found a dichotomy in the polarization properties between Chandrasekhar and sub-Chandrasekhar mass explosions, which supports the possibility of two distinct explosion mechanisms. A subsample of SNe displays evolution of loops in the q–u plane that suggests a more complex Si structure with depth. This insight, which could not be gleaned from total flux spectra, presents a new constraint on explosion models. Finally, we compared our statistical sample of the Si ii polarization to quantitative predictions of the polarization levels for the double-detonation, delayed-detonation, and violent-merger models.

scholarly journals Continuous gravitational waves from magnetized white dwarfs

2019 ◽  
Vol 15 (S357) ◽  
pp. 79-83
Author(s):  
Surajit Kalita ◽  
Banibrata Mukhopadhyay
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
White Dwarfs ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae

AbstractRecent evidence of super-Chandrasekhar white dwarfs (WDs), from the observations of over-luminous type Ia supernovae (SNeIa), has been a great astrophysical discovery. However, no such massive WDs have so far been observed directly as their luminosities are generally quite low. Hence it immediately raises the question of whether there is any possibility of detecting them directly. The search for super-Chandrasekhar WDs is very important as SNeIa are used as standard candles in cosmology. In this article, we show that continuous gravitational wave can allow us to detect such super-Chandrasekhar WDs directly.

scholarly journals STUDY OF THE DETONATION PHASE IN THE GRAVITATIONALLY CONFINED DETONATION MODEL OF TYPE Ia SUPERNOVAE

2009 ◽  
Vol 693 (2) ◽  
pp. 1188-1208 ◽  
Author(s):  
Casey A. Meakin ◽  
Ivo Seitenzahl ◽  
Dean Townsley ◽  
George C. Jordan ◽  
James Truran ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae ◽  
Detonation Model

Three‐dimensional Delayed‐Detonation Model of Type Ia Supernovae

2005 ◽  
Vol 623 (1) ◽  
pp. 337-346 ◽  
Author(s):  
Vadim N. Gamezo ◽  
Alexei M. Khokhlov ◽  
Elaine S. Oran
Keyword(s):  
Three Dimensional ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae ◽  
Detonation Model

scholarly journals Sub-Chandrasekhar-mass detonations are in tension with the observed t0−MNi56 relation of type Ia supernovae

2020 ◽  
Vol 499 (4) ◽  
pp. 4725-4747
Author(s):  
Doron Kushnir ◽  
Nahliel Wygoda ◽  
Amir Sharon
Keyword(s):  
White Dwarf ◽  
Numerical Scheme ◽  
Radiation Transfer ◽  
Type Ia Supernovae ◽  
Escape Time ◽  
The Core ◽  
Type Ia ◽  
Γ Rays ◽  
Ia Supernovae ◽  
Detonation Model

ABSTRACT Type Ia supernovae (SNe Ia) are likely the thermonuclear explosions of carbon–oxygen (CO) white-dwarf (WD) stars, but their progenitor systems remain elusive. Recent studies have suggested that a propagating detonation within a thin helium shell surrounding a sub-Chandrasekhar mass CO core can subsequently trigger a detonation within the core (the double-detonation model, DDM). The outcome of this explosion is similar to a central ignition of a sub-Chandrasekhar mass CO WD (SCD). While SCD is consistent with some observational properties of SNe Ia, several computational challenges prohibit a robust comparison to the observations. We focus on the observed t0−MNi56 relation, where t0 (the γ-rays’ escape time from the ejecta) is positively correlated with MNi56 (the synthesized 56Ni mass). We apply our recently developed numerical scheme to calculate SCD and show that the calculated t0−MNi56 relation, which does not require radiation transfer calculations, converges to an accuracy of a few per cent. We find a clear tension between our calculations and the observed t0−MNi56 relation. SCD predicts an anticorrelation between t0 and MNi56, with $t_0\approx 30\, \textrm{d}$ for luminous ($M_\text{Ni56}\gtrsim 0.5\, \mathrm{ M}_{\odot }$) SNe Ia, while the observed t0 is in the range of $35\!-\!45\, \textrm{d}$. We show that this tension is larger than the uncertainty of the results, and that it exists in all previous studies of the problem. Our results hint that more complicated models are required, but we argue that DDM is unlikely to resolve the tension with the observations.

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