A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Complexity in the light curves and spectra of slow-evolving superluminous supernovae
Tekijät: Inserra C, Nicholl M, Chen TW, Jerkstrand A, Smartt SJ, Kruhler T, Anderson JP, Baltay C, Della Valle M, Fraser M, Gal-Yam A, Galbany L, Kankare E, Maguire K, Rabinowitz D, Smith K, Valenti S, Young DR
Kustantaja: OXFORD UNIV PRESS
Julkaisuvuosi: 2017
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: 468
Numero: 4
Aloitussivu: 4642
Lopetussivu: 4662
Sivujen määrä: 21
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stx834
Tiivistelmä
A small group of the newly discovered superluminous supernovae show broad and slow-evolving light curves. Here we present extensive observational data for the slow-evolving superluminous supernova LSQ14an, which brings this group of transients to four in total in the low-redshift Universe (z < 0.2; SN 2007bi, PTF12dam, SN 2015bn). We particularly focus on the optical and near-infrared evolution during the period from 50 d up to 400 d from peak, showing that they are all fairly similar in their light curve and spectral evolution. LSQ14an shows broad, blueshifted [O III] lambda lambda 4959, 5007 lines, as well as a blueshifted [O II] lambda lambda 7320, 7330 and [Ca II]lambda lambda 7291, 7323. Furthermore, the sample of these four objects shows common features. Semi-forbidden and forbidden emission lines appear surprisingly early at 50-70 d and remain visible with almost no variation up to 400 d. The spectra remain blue out to 400 d. There are small, but discernible light-curve fluctuations in all of them. The light curve of each shows a faster decline than Co-56 after 150 d and it further steepens after 300 d. We also expand our analysis presenting X-ray limits for LSQ14an and SN 2015bn and discuss their diagnostic power. These features are quite distinct from the faster evolving superluminous supernovae and are not easily explained in terms of only a variation in ejecta mass. While a central engine is still the most likely luminosity source, it appears that the ejecta structure is complex, with multiple emitting zones and at least some interaction between the expanding ejecta and surrounding material.
A small group of the newly discovered superluminous supernovae show broad and slow-evolving light curves. Here we present extensive observational data for the slow-evolving superluminous supernova LSQ14an, which brings this group of transients to four in total in the low-redshift Universe (z < 0.2; SN 2007bi, PTF12dam, SN 2015bn). We particularly focus on the optical and near-infrared evolution during the period from 50 d up to 400 d from peak, showing that they are all fairly similar in their light curve and spectral evolution. LSQ14an shows broad, blueshifted [O III] lambda lambda 4959, 5007 lines, as well as a blueshifted [O II] lambda lambda 7320, 7330 and [Ca II]lambda lambda 7291, 7323. Furthermore, the sample of these four objects shows common features. Semi-forbidden and forbidden emission lines appear surprisingly early at 50-70 d and remain visible with almost no variation up to 400 d. The spectra remain blue out to 400 d. There are small, but discernible light-curve fluctuations in all of them. The light curve of each shows a faster decline than Co-56 after 150 d and it further steepens after 300 d. We also expand our analysis presenting X-ray limits for LSQ14an and SN 2015bn and discuss their diagnostic power. These features are quite distinct from the faster evolving superluminous supernovae and are not easily explained in terms of only a variation in ejecta mass. While a central engine is still the most likely luminosity source, it appears that the ejecta structure is complex, with multiple emitting zones and at least some interaction between the expanding ejecta and surrounding material.
Turun yliopiston Tutkimustietojärjestelmän portaali