SN 2017egm: A Helium-rich Superluminous Supernova with Multiple Bumps in the Light Curves
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
SN 2017egm : A Helium-rich Superluminous Supernova with Multiple Bumps in the Light Curves. / Zhu, Jiazheng; Jiang, Ning; Dong, Subo; Filippenko, Alexei V.; Rudy, Richard J.; Pastorello, A.; Ashall, Christopher; Bose, Subhash; Post, R. S.; Bersier, D.; Benetti, Stefano; Brink, Thomas G.; Chen, Ping; Dou, Liming; Elias-Rosa, N.; Lundqvist, Peter; Mattila, Seppo; Russell, Ray W.; Sitko, Michael L.; Somero, Auni; Stritzinger, M. D.; Wang, Tinggui; Brown, Peter J.; Cappellaro, E.; Fraser, Morgan; Kankare, Erkki; Moran, S.; Prentice, Simon; Pursimo, Tapio; Reynolds, T. M.; Zheng, WeiKang.
In: Astrophysical Journal, Vol. 949, No. 1, 23, 01.05.2023.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - SN 2017egm
T2 - A Helium-rich Superluminous Supernova with Multiple Bumps in the Light Curves
AU - Zhu, Jiazheng
AU - Jiang, Ning
AU - Dong, Subo
AU - Filippenko, Alexei V.
AU - Rudy, Richard J.
AU - Pastorello, A.
AU - Ashall, Christopher
AU - Bose, Subhash
AU - Post, R. S.
AU - Bersier, D.
AU - Benetti, Stefano
AU - Brink, Thomas G.
AU - Chen, Ping
AU - Dou, Liming
AU - Elias-Rosa, N.
AU - Lundqvist, Peter
AU - Mattila, Seppo
AU - Russell, Ray W.
AU - Sitko, Michael L.
AU - Somero, Auni
AU - Stritzinger, M. D.
AU - Wang, Tinggui
AU - Brown, Peter J.
AU - Cappellaro, E.
AU - Fraser, Morgan
AU - Kankare, Erkki
AU - Moran, S.
AU - Prentice, Simon
AU - Pursimo, Tapio
AU - Reynolds, T. M.
AU - Zheng, WeiKang
PY - 2023/5/1
Y1 - 2023/5/1
N2 - When discovered, SN 2017egm was the closest (redshift z = 0.03) hydrogen-poor superluminous supernova (SLSN-I) and a rare case that exploded in a massive and metal-rich galaxy. Thus, it has since been extensively observed and studied. We report spectroscopic data showing strong emission at around He i lambda 10830 and four He i absorption lines in the optical. Consequently, we classify SN 2017egm as a member of an emerging population of helium-rich SLSNe-I (i.e., SLSNe-Ib). We also present our late-time photometric observations. By combining them with archival data, we analyze high-cadence ultraviolet, optical, and near-infrared light curves spanning from early pre-peak (similar to-20 days) to late phases (similar to+300 days). We obtain its most complete bolometric light curve, in which multiple bumps are identified. None of the previously proposed models can satisfactorily explain all main light-curve features, while multiple interactions between the ejecta and circumstellar material (CSM) may explain the undulating features. The prominent infrared excess with a blackbody luminosity of 10(7)-10(8) L (circle dot) detected in SN 2017egm could originate from the emission of either an echo of a pre-existing dust shell or newly formed dust, offering an additional piece of evidence supporting the ejecta-CSM interaction model. Moreover, our analysis of deep Chandra observations yields the tightest-ever constraint on the X-ray emission of an SLSN-I, amounting to an X-ray-to-optical luminosity ratio less than or similar to 10(-3) at late phases (similar to 100-200 days), which could help explore its close environment and central engine.
AB - When discovered, SN 2017egm was the closest (redshift z = 0.03) hydrogen-poor superluminous supernova (SLSN-I) and a rare case that exploded in a massive and metal-rich galaxy. Thus, it has since been extensively observed and studied. We report spectroscopic data showing strong emission at around He i lambda 10830 and four He i absorption lines in the optical. Consequently, we classify SN 2017egm as a member of an emerging population of helium-rich SLSNe-I (i.e., SLSNe-Ib). We also present our late-time photometric observations. By combining them with archival data, we analyze high-cadence ultraviolet, optical, and near-infrared light curves spanning from early pre-peak (similar to-20 days) to late phases (similar to+300 days). We obtain its most complete bolometric light curve, in which multiple bumps are identified. None of the previously proposed models can satisfactorily explain all main light-curve features, while multiple interactions between the ejecta and circumstellar material (CSM) may explain the undulating features. The prominent infrared excess with a blackbody luminosity of 10(7)-10(8) L (circle dot) detected in SN 2017egm could originate from the emission of either an echo of a pre-existing dust shell or newly formed dust, offering an additional piece of evidence supporting the ejecta-CSM interaction model. Moreover, our analysis of deep Chandra observations yields the tightest-ever constraint on the X-ray emission of an SLSN-I, amounting to an X-ray-to-optical luminosity ratio less than or similar to 10(-3) at late phases (similar to 100-200 days), which could help explore its close environment and central engine.
U2 - 10.3847/1538-4357/acc2c3
DO - 10.3847/1538-4357/acc2c3
M3 - Journal article
VL - 949
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 23
ER -
ID: 355102811