ASASSN-18am/SN 2018gk: an overluminous Type IIb supernova from a massive progenitor

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ASASSN-18am/SN 2018gk : an overluminous Type IIb supernova from a massive progenitor. / Bose, Subhash; Dong, Subo; Kochanek, C. S.; Stritzinger, M. D.; Ashall, Chris; Benetti, Stefano; Falco, E.; Filippenko, Alexei; Pastorello, Andrea; Prieto, Jose L.; Somero, Auni; Sukhbold, Tuguldur; Zhang, Junbo; Auchettl, Katie; Brink, Thomas G.; Brown, J. S.; Chen, Ping; Fiore, A.; Grupe, Dirk; Holoien, T. W. S.; Lundqvist, Peter; Mattila, Seppo; Mutel, Robert; Pooley, David; Post, R. S.; Reddy, Naveen; Reynolds, Thomas M.; Shappee, Benjamin J.; Stanek, K. Z.; Thompson, Todd A.; Villanueva, S. jR; Zheng, Weikang.

In: Monthly Notices of the Royal Astronomical Society, Vol. 503, No. 3, 05.2021, p. 3472-3491.

Research output: Contribution to journalJournal articleResearchpeer-review

Harvard

Bose, S, Dong, S, Kochanek, CS, Stritzinger, MD, Ashall, C, Benetti, S, Falco, E, Filippenko, A, Pastorello, A, Prieto, JL, Somero, A, Sukhbold, T, Zhang, J, Auchettl, K, Brink, TG, Brown, JS, Chen, P, Fiore, A, Grupe, D, Holoien, TWS, Lundqvist, P, Mattila, S, Mutel, R, Pooley, D, Post, RS, Reddy, N, Reynolds, TM, Shappee, BJ, Stanek, KZ, Thompson, TA, Villanueva, SJR & Zheng, W 2021, 'ASASSN-18am/SN 2018gk: an overluminous Type IIb supernova from a massive progenitor', Monthly Notices of the Royal Astronomical Society, vol. 503, no. 3, pp. 3472-3491. https://doi.org/10.1093/mnras/stab629

APA

Bose, S., Dong, S., Kochanek, C. S., Stritzinger, M. D., Ashall, C., Benetti, S., Falco, E., Filippenko, A., Pastorello, A., Prieto, J. L., Somero, A., Sukhbold, T., Zhang, J., Auchettl, K., Brink, T. G., Brown, J. S., Chen, P., Fiore, A., Grupe, D., ... Zheng, W. (2021). ASASSN-18am/SN 2018gk: an overluminous Type IIb supernova from a massive progenitor. Monthly Notices of the Royal Astronomical Society, 503(3), 3472-3491. https://doi.org/10.1093/mnras/stab629

Vancouver

Bose S, Dong S, Kochanek CS, Stritzinger MD, Ashall C, Benetti S et al. ASASSN-18am/SN 2018gk: an overluminous Type IIb supernova from a massive progenitor. Monthly Notices of the Royal Astronomical Society. 2021 May;503(3):3472-3491. https://doi.org/10.1093/mnras/stab629

Author

Bose, Subhash ; Dong, Subo ; Kochanek, C. S. ; Stritzinger, M. D. ; Ashall, Chris ; Benetti, Stefano ; Falco, E. ; Filippenko, Alexei ; Pastorello, Andrea ; Prieto, Jose L. ; Somero, Auni ; Sukhbold, Tuguldur ; Zhang, Junbo ; Auchettl, Katie ; Brink, Thomas G. ; Brown, J. S. ; Chen, Ping ; Fiore, A. ; Grupe, Dirk ; Holoien, T. W. S. ; Lundqvist, Peter ; Mattila, Seppo ; Mutel, Robert ; Pooley, David ; Post, R. S. ; Reddy, Naveen ; Reynolds, Thomas M. ; Shappee, Benjamin J. ; Stanek, K. Z. ; Thompson, Todd A. ; Villanueva, S. jR ; Zheng, Weikang. / ASASSN-18am/SN 2018gk : an overluminous Type IIb supernova from a massive progenitor. In: Monthly Notices of the Royal Astronomical Society. 2021 ; Vol. 503, No. 3. pp. 3472-3491.

Bibtex

@article{d1c47facda4545319ddc50c39354a1f9,
title = "ASASSN-18am/SN 2018gk: an overluminous Type IIb supernova from a massive progenitor",
abstract = "ASASSN-18am/SN 2018gk is a newly discovered member of the rare group of luminous, hydrogen-rich supernovae (SNe) with a peak absolute magnitude of M-V approximate to -20 mag that is in between normal core-collapse SNe and superluminous SNe. These SNe show no prominent spectroscopic signatures of ejecta interacting with circumstellar material (CSM), and their powering mechanism is debated. ASASSN-18am declines extremely rapidly for a Type II SN, with a photospheric-phase decline rate of similar to 6.0 mag (100 d)(-1). Owing to the weakening of H I and the appearance of He I in its later phases, ASASSN-18am is spectroscopically a Type IIb SN with a partially stripped envelope. However, its photometric and spectroscopic evolution shows significant differences from typical SNe IIb. Using a radiative diffusion model, we find that the light curve requires a high synthesized Ni-56 mass M-Ni similar to 0.4 M-circle dot and ejecta with high kinetic energy E-kin = (7-10) x 10(51) erg. Introducing a magnetar central engine still requires M-Ni similar to 0.3 M-circle dot and E-kin = 3 x 10(51) erg. The high Ni-56 mass is consistent with strong iron-group nebular lines in its spectra, which are also similar to several SNe Ic-BL with high Ni-56 yields. The earliest spectrum shows 'flash ionization' features, from which we estimate a mass-loss rate of (M) over dot approximate to 2 x 10(-4 )M(circle dot) yr(-1). This wind density is too low to power the luminous light curve by ejecta-CSM interaction. We measure expansion velocities as high as 17 000 km s(-1) for H alpha, which is remarkably high compared to other SNe II. We estimate an oxygen core mass of 1.8-3.4 M-circle dot using the [O I] luminosity measured from a nebular-phase spectrum, implying a progenitor with a zero-age main-sequence mass of 19-26 M-circle dot.",
keywords = "supernovae: general, supernovae: individual: (ASASSN-18am/SN 2018gk), galaxies: individual: WISE J163554.27+400151.8, CORE-COLLAPSE SUPERNOVAE, NEUTRINO-DRIVEN EXPLOSION, LIGHT-CURVES, SN 2013EJ, EVOLUTION, EMISSION, SPECTRA, SAMPLE, GALAXY, DUST",
author = "Subhash Bose and Subo Dong and Kochanek, {C. S.} and Stritzinger, {M. D.} and Chris Ashall and Stefano Benetti and E. Falco and Alexei Filippenko and Andrea Pastorello and Prieto, {Jose L.} and Auni Somero and Tuguldur Sukhbold and Junbo Zhang and Katie Auchettl and Brink, {Thomas G.} and Brown, {J. S.} and Ping Chen and A. Fiore and Dirk Grupe and Holoien, {T. W. S.} and Peter Lundqvist and Seppo Mattila and Robert Mutel and David Pooley and Post, {R. S.} and Naveen Reddy and Reynolds, {Thomas M.} and Shappee, {Benjamin J.} and Stanek, {K. Z.} and Thompson, {Todd A.} and Villanueva, {S. jR} and Weikang Zheng",
year = "2021",
month = may,
doi = "10.1093/mnras/stab629",
language = "English",
volume = "503",
pages = "3472--3491",
journal = "Royal Astronomical Society. Monthly Notices",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",

}

RIS

TY - JOUR

T1 - ASASSN-18am/SN 2018gk

T2 - an overluminous Type IIb supernova from a massive progenitor

AU - Bose, Subhash

AU - Dong, Subo

AU - Kochanek, C. S.

AU - Stritzinger, M. D.

AU - Ashall, Chris

AU - Benetti, Stefano

AU - Falco, E.

AU - Filippenko, Alexei

AU - Pastorello, Andrea

AU - Prieto, Jose L.

AU - Somero, Auni

AU - Sukhbold, Tuguldur

AU - Zhang, Junbo

AU - Auchettl, Katie

AU - Brink, Thomas G.

AU - Brown, J. S.

AU - Chen, Ping

AU - Fiore, A.

AU - Grupe, Dirk

AU - Holoien, T. W. S.

AU - Lundqvist, Peter

AU - Mattila, Seppo

AU - Mutel, Robert

AU - Pooley, David

AU - Post, R. S.

AU - Reddy, Naveen

AU - Reynolds, Thomas M.

AU - Shappee, Benjamin J.

AU - Stanek, K. Z.

AU - Thompson, Todd A.

AU - Villanueva, S. jR

AU - Zheng, Weikang

PY - 2021/5

Y1 - 2021/5

N2 - ASASSN-18am/SN 2018gk is a newly discovered member of the rare group of luminous, hydrogen-rich supernovae (SNe) with a peak absolute magnitude of M-V approximate to -20 mag that is in between normal core-collapse SNe and superluminous SNe. These SNe show no prominent spectroscopic signatures of ejecta interacting with circumstellar material (CSM), and their powering mechanism is debated. ASASSN-18am declines extremely rapidly for a Type II SN, with a photospheric-phase decline rate of similar to 6.0 mag (100 d)(-1). Owing to the weakening of H I and the appearance of He I in its later phases, ASASSN-18am is spectroscopically a Type IIb SN with a partially stripped envelope. However, its photometric and spectroscopic evolution shows significant differences from typical SNe IIb. Using a radiative diffusion model, we find that the light curve requires a high synthesized Ni-56 mass M-Ni similar to 0.4 M-circle dot and ejecta with high kinetic energy E-kin = (7-10) x 10(51) erg. Introducing a magnetar central engine still requires M-Ni similar to 0.3 M-circle dot and E-kin = 3 x 10(51) erg. The high Ni-56 mass is consistent with strong iron-group nebular lines in its spectra, which are also similar to several SNe Ic-BL with high Ni-56 yields. The earliest spectrum shows 'flash ionization' features, from which we estimate a mass-loss rate of (M) over dot approximate to 2 x 10(-4 )M(circle dot) yr(-1). This wind density is too low to power the luminous light curve by ejecta-CSM interaction. We measure expansion velocities as high as 17 000 km s(-1) for H alpha, which is remarkably high compared to other SNe II. We estimate an oxygen core mass of 1.8-3.4 M-circle dot using the [O I] luminosity measured from a nebular-phase spectrum, implying a progenitor with a zero-age main-sequence mass of 19-26 M-circle dot.

AB - ASASSN-18am/SN 2018gk is a newly discovered member of the rare group of luminous, hydrogen-rich supernovae (SNe) with a peak absolute magnitude of M-V approximate to -20 mag that is in between normal core-collapse SNe and superluminous SNe. These SNe show no prominent spectroscopic signatures of ejecta interacting with circumstellar material (CSM), and their powering mechanism is debated. ASASSN-18am declines extremely rapidly for a Type II SN, with a photospheric-phase decline rate of similar to 6.0 mag (100 d)(-1). Owing to the weakening of H I and the appearance of He I in its later phases, ASASSN-18am is spectroscopically a Type IIb SN with a partially stripped envelope. However, its photometric and spectroscopic evolution shows significant differences from typical SNe IIb. Using a radiative diffusion model, we find that the light curve requires a high synthesized Ni-56 mass M-Ni similar to 0.4 M-circle dot and ejecta with high kinetic energy E-kin = (7-10) x 10(51) erg. Introducing a magnetar central engine still requires M-Ni similar to 0.3 M-circle dot and E-kin = 3 x 10(51) erg. The high Ni-56 mass is consistent with strong iron-group nebular lines in its spectra, which are also similar to several SNe Ic-BL with high Ni-56 yields. The earliest spectrum shows 'flash ionization' features, from which we estimate a mass-loss rate of (M) over dot approximate to 2 x 10(-4 )M(circle dot) yr(-1). This wind density is too low to power the luminous light curve by ejecta-CSM interaction. We measure expansion velocities as high as 17 000 km s(-1) for H alpha, which is remarkably high compared to other SNe II. We estimate an oxygen core mass of 1.8-3.4 M-circle dot using the [O I] luminosity measured from a nebular-phase spectrum, implying a progenitor with a zero-age main-sequence mass of 19-26 M-circle dot.

KW - supernovae: general

KW - supernovae: individual: (ASASSN-18am/SN 2018gk)

KW - galaxies: individual: WISE J163554.27+400151.8

KW - CORE-COLLAPSE SUPERNOVAE

KW - NEUTRINO-DRIVEN EXPLOSION

KW - LIGHT-CURVES

KW - SN 2013EJ

KW - EVOLUTION

KW - EMISSION

KW - SPECTRA

KW - SAMPLE

KW - GALAXY

KW - DUST

U2 - 10.1093/mnras/stab629

DO - 10.1093/mnras/stab629

M3 - Journal article

VL - 503

SP - 3472

EP - 3491

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 3

ER -

ID: 271822207