A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
The Type I superluminous supernova catalogue – II. Spectroscopic evolution in the photospheric phase, velocity measurements, and constraints on diversity
Tekijät: Aamer, Aysha; Nicholl, Matt; Gomez, Sebastian; Berger, Edo; Blanchard, Peter; Anderson, Joseph P.; Angus, Charlotte; Aryan, Amar; Ashall, Chris; Chen, Ting-Wan; Dimitriadis, Georgios; Galbany, Lluis; Gkini, Anamaria; Gromadzki, Mariusz; Gutierrez, Claudia P.; Hiramatsu, Daichi; Hosseinzadeh, Griffin; Inserra, Cosimo; Kumar, Amit; Kumar, Harsh; Kuncarayakti, Hanindyo; Leloudas, Giorgos; Mazzali, Paolo; Medler, Kyle; Muller-Bravo, Tomas E.; Ramirez, Mauricio; Sankar.K, Aiswarya; Schulze, Steve; Singh, Avinash; Sollerman, Jesper; Srivastav, Shubham; Terwel, Jacco H.; Young, David R.
Kustantaja: Oxford University Press (OUP)
Kustannuspaikka: OXFORD
Julkaisuvuosi: 2025
Journal: Monthly Notices of the Royal Astronomical Society
Tietokannassa oleva lehden nimi: Monthly Notices of the Royal Astronomical Society
Lehden akronyymi: MON NOT R ASTRON SOC
Vuosikerta: 541
Numero: 3
Aloitussivu: 2674
Lopetussivu: 2706
Sivujen määrä: 33
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/staf1113
Verkko-osoite: https://doi.org/10.1093/mnras/staf1113
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/499699931
Hydrogen-poor superluminous supernovae (SLSNe) are among the most energetic explosions in the universe, reaching luminosities up to 100 times greater than those of normal supernovae. This paper presents the largest compilation of SLSN photospheric spectra to date, encompassing data from the advanced Public ESO Spectroscopic Survey of Transient Objects (ePESSTO+), the Finding Luminous and Exotic Extragalactic Transients (FLEET) search, and all published spectra up to December 2022. The data set includes a total of 974 spectra of 234 SLSNe. By constructing average phase binned spectra, we find SLSNe initially exhibit high temperatures (10 000−11 000 K), with blue continua and weak lines. A rapid transformation follows, as temperatures drop to 5000−6000 K by 40 d post-peak, leading to stronger P-Cygni features. Variance within the data set is slightly reduced when defining the phase of spectra relative to explosion, rather than peak, and normalising to the population’s median e-folding decline time. Principal Component Analysis (PCA) supports this, requiring fewer components to explain the same level of variation when binning data by scaled days from explosion, suggesting a more homogeneous grouping. Using PCA and K-means clustering, we identify outlying objects with unusual spectroscopic evolution and evidence for energy input from interaction, but find no support for groupings of two or more statistically significant subpopulations. We find Fe II λ5169 line velocities closely track the radius implied from blackbody fits, indicating formation near the photosphere. We also confirm a correlation between velocity and velocity gradient, which can be explained if all SLSNe are in homologous expansion but with different scale velocities. This behaviour aligns with expectations for an internal powering mechanism.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
Julkaisussa olevat rahoitustiedot:
AA and MN are supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no.948381).
SG is supported by an STScI Postdoctoral Fellowship.
The Berger Time-Domain Group is supported in part by NSF and NASA funds.
AA and T-WC acknowledge the Yushan Young Fellow Program by the Ministry of Education, Taiwan, for the financial support (MOE-111-YSFMS-0008-001-P1).
This work was funded by ANID, Millennium Science Initiative, ICN12_009.
LG and CPG acknowledge financial support from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016, the Spanish Ministerio de Ciencia e Innovación (MCIN) and the Agencia Estatal de Investigación (AEI) 10.13039/501100011033 under the PID2023-151307NB-I00 SNNEXT project, the program Unidad de Excelencia María de Maeztu CEX2020-001058-M, and the Departament de Recerca i Universitats de la Generalitat de Catalunya through the 2021-SGR-01270 grant. LG also acknowledges financial support from AGAUR, ILINK23001, and COOPB2304. CPG acknowledges financial support from the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 Research and Innovation Programme of the European Union under the Marie Skłodowska-Curie and the Beatriu de Pinós 2021 BP 00168 programme.
HK was funded by the Research Council of Finland projects 324504, 328898, and 353019.
GL was supported by a research grant (VIL60862) from VILLUM FONDEN.
TEMB is funded by Horizon Europe ERC grant no. 101125877.
MR acknowledge support from National Agency for Research and Development (ANID) grants ANID-PFCHA/Doctorado Nacional/2020-21202606.
AS acknowledges support from the Knut and Alice Wallenberg foundation through the ‘Gravity Meets Light’ project.
SS is partially supported by LBNL Subcontract 7707915.
