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P. Clark - One of the best experts on this subject based on the ideXlab platform.
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The rise and fall of an extraordinary Ca-rich transient: the discovery of ATLAS19dqr/SN 2019bkc
Astronomy and Astrophysics, 2020Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kiloparsecs from any likely host. Its light curves rise to maximum light in 5-6 d and then display a decline of Δm15 ∼ 5 mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe, but the early nebular phase spectra, which were reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10 000-12 000 km s-1. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of 0.2-0.4 M⊙ and a low Kinetic Energy of (2-4) × 1050 erg, giving a Specific Kinetic Energy Ek/Mej ∼ 1 [1051 erg]/M⊙. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events. © ESO 2020.
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The rise and fall of an extraordinary Ca-rich transient -- The discovery of ATLAS19dqr/SN 2019bkc
arXiv: High Energy Astrophysical Phenomena, 2019Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kpc from any likely host. Its light curves rise to maximum light in $5-6$ d and then display an decline of $\Delta m_{15} \sim5$ mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe but the early nebular phase spectra, reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10,000 -- 12,000 km/s. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of $0.2 - 0.4$ M$_{\odot}$ and a low Kinetic Energy of $ (2-5)\times 10^{50}$ erg, giving a Specific Kinetic Energy around unity. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events.
Bernd Zimanowski - One of the best experts on this subject based on the ideXlab platform.
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A new method for the determination of the Specific Kinetic Energy (SKE) released to pyroclastic particles at magmatic fragmentation: theory and first experimental results
Bulletin of Volcanology, 2012Co-Authors: Tobias Dürig, Fabio Dioguardi, Ralf Büttner, Pierfrancesco Dellino, Daniela Mele, Bernd ZimanowskiAbstract:Brittle magmatic fragmentation plays a crucial role in explosive eruptions. It represents the starting point of hazardous explosive events that can affect large areas surrounding erupting volcanoes. Knowing the initial Energy released during this fragmentation process is fundamental for the understanding of the subsequent dynamics of the eruptive gas-particle mixture and consequently for the forecasting of the erupting column’s behavior. The Specific Kinetic Energy (SKE) of the particles quantifies the initial velocity shortly after the fragmentation and is therefore a necessary variable to model the gas-particle conduit flow and eruptive column regime. In this paper, we present a new method for its determination based on fragmentation experiments and identification of the timings of Energy release. The results obtained on compositions representative for basaltic and phonolitic melts show a direct dependence on magma material properties: poorly vesiculated basaltic melts from Stromboli show the highest SKE values ranging from 7.3 to 11.8 kJ/kg, while experiments with highly vesiculated samples from Stromboli and Vesuvius result in lower SKE values (3.1 to 3.8 kJ/kg). The described methodology presents a useful tool for quantitative estimation of the Kinetic Energy release of magmatic fragmentation processes, which can contribute to the improvement of hazard assessment.
C Ashall - One of the best experts on this subject based on the ideXlab platform.
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The rise and fall of an extraordinary Ca-rich transient: the discovery of ATLAS19dqr/SN 2019bkc
Astronomy and Astrophysics, 2020Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kiloparsecs from any likely host. Its light curves rise to maximum light in 5-6 d and then display a decline of Δm15 ∼ 5 mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe, but the early nebular phase spectra, which were reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10 000-12 000 km s-1. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of 0.2-0.4 M⊙ and a low Kinetic Energy of (2-4) × 1050 erg, giving a Specific Kinetic Energy Ek/Mej ∼ 1 [1051 erg]/M⊙. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events. © ESO 2020.
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The rise and fall of an extraordinary Ca-rich transient -- The discovery of ATLAS19dqr/SN 2019bkc
arXiv: High Energy Astrophysical Phenomena, 2019Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kpc from any likely host. Its light curves rise to maximum light in $5-6$ d and then display an decline of $\Delta m_{15} \sim5$ mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe but the early nebular phase spectra, reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10,000 -- 12,000 km/s. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of $0.2 - 0.4$ M$_{\odot}$ and a low Kinetic Energy of $ (2-5)\times 10^{50}$ erg, giving a Specific Kinetic Energy around unity. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events.
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a physical basis for the h band blue edge velocity and light curve shape correlation in context of type ia supernova explosion physics
arXiv: High Energy Astrophysical Phenomena, 2019Co-Authors: C Ashall, M Stritzinger, Anthony L Piro, C R Burns, M M Phillips, P Hoeflich, E Y Hsiao, C Contreras, E Baron, S. DavisAbstract:Our recent work demonstrates a correlation between the high-velocity blue edge, $v_{edge}$, of the iron-peak Fe/Co/Ni $H$-band emission feature and the optical light curve shape of normal, transitional and sub-luminous type Ia Supernovae (SNe Ia). We explain this correlation in terms of SN Ia physics. $v_{edge}$ corresponds to the sharp transition between the complete and incomplete silicon burning regions in the ejecta. It measures the point in velocity space where the outer $^{56}$Ni mass fraction, $X_{\rm{Ni}}$, falls to the order of 0.03-0.10. For a given $^{56}$Ni mass, $M(^{56}Ni)$, $v_{edge}$ is sensitive to the Specific Kinetic Energy $E_{\rm kin}$($M(^{56}Ni)/M_{WD}$) of the corresponding region. Combining $v_{edge}$ with light curve parameters (i.e., s$_{BV}$, $\Delta m_{15,s}$ in $B$ and $V$) allows us to distinguish between explosion scenarios. The correlation between $v_{edge}$ and light-curve shape is consistent with explosion models near the Chandrasekhar limit. However, the available sub-$M_{Ch}$ WD explosion model based on SN 1999by exhibits velocities which are too large to explain the observations. Finally, the sub-luminous SN 2015bo exhibits signatures of a dynamical merger of two WDs demonstrating diversity among explosion scenarios at the faint end of the SNe Ia population.
Kun Yu - One of the best experts on this subject based on the ideXlab platform.
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a study on the comprehension of differences in Specific Kinetic Energy of tkx 50 and hmx from the perspective of gas products
Physical Chemistry Chemical Physics, 2019Co-Authors: Chuande Zhao, Qiang Peng, Fang Yang, Jianhua Zhou, Xinfeng Wang, Kun YuAbstract:5,5′-Bitetrazole-1,1′-dioxydihydroxylamine salt (TKX-50), a high-Energy energetic material, possesses good safety and Energy properties. The Energy characteristic data of TKX-50 are commonly generated via theoretical simulation and experimental measurements. Interestingly, the detonation velocity of TKX-50 is higher than HMX, but the Specific Kinetic Energy of TKX-50 is the opposite. Thus, a systematic study on the decomposition mechanism of TKX-50 is important to establish the reasons for this variation in Specific Kinetic Energy. Although the thermal decomposition mechanism of TKX-50 has been reported, the Specific compositional changes of its gas products under different heating conditions remain unknown, hindering a comprehensive understanding of the mechanism from the perspective of gas products. Herein, the gas products of TKX-50 and HMX in thermal decomposition and thermal explosion are investigated and compared. It was found that more TKX-50 is converted to ABTOX for further decomposition when the heating rate increases. ABTOX can decompose to C2N2, which is prone to polymerization, generating a solid residue under high temperature and pressure. Although polymerized C2N2 decomposes and burns during the explosion, it delays the time of TKX-50 reaching its maximum amount of outgassing, thereby affecting its Specific Kinetic Energy. Furthermore, in the thermal explosion, compared with HMX, TKX-50 generates less H2 and CO. Since the combustion heat of hydrogen is much higher than that of carbon, the more hydrogen generated, the higher the detonation heat obtained. Therefore, TKX-50 has a lower detonation heat, which also affects its Specific Kinetic Energy.
Simon Prentice - One of the best experts on this subject based on the ideXlab platform.
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The rise and fall of an extraordinary Ca-rich transient: the discovery of ATLAS19dqr/SN 2019bkc
Astronomy and Astrophysics, 2020Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kiloparsecs from any likely host. Its light curves rise to maximum light in 5-6 d and then display a decline of Δm15 ∼ 5 mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe, but the early nebular phase spectra, which were reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10 000-12 000 km s-1. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of 0.2-0.4 M⊙ and a low Kinetic Energy of (2-4) × 1050 erg, giving a Specific Kinetic Energy Ek/Mej ∼ 1 [1051 erg]/M⊙. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events. © ESO 2020.
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The rise and fall of an extraordinary Ca-rich transient -- The discovery of ATLAS19dqr/SN 2019bkc
arXiv: High Energy Astrophysical Phenomena, 2019Co-Authors: Simon Prentice, C Ashall, Kate Maguire, A. Flörs, S. Taubenberger, Cosimo Inserra, C. Frohmaier, T. W. Chen, J. P. Anderson, P. ClarkAbstract:This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kpc from any likely host. Its light curves rise to maximum light in $5-6$ d and then display an decline of $\Delta m_{15} \sim5$ mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and "ultra-stripped" type Ic SNe but the early nebular phase spectra, reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10,000 -- 12,000 km/s. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of $0.2 - 0.4$ M$_{\odot}$ and a low Kinetic Energy of $ (2-5)\times 10^{50}$ erg, giving a Specific Kinetic Energy around unity. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of Ar II, the Specific Kinetic Energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events.