Intermediate-luminosity red transients: Spectrophotometric properties and connection to electron-capture supernova explosions

Y. Z. Cai, A. Pastorello, M. Fraser, M. T. Botticella, N. Elias-Rosa, L. Z. Wang, R. Kotak, S. Benetti, E. Cappellaro, M. Turatto, A. Reguitti, S. Mattila, S. J. Smartt, C. Ashall, S. Benitez, T. W. Chen, A. Harutyunyan, E. Kankare, P. Lundqvist, P. A. MazzaliA. Morales-Garoffolo, P. Ochner, G. Pignata, S. J. Prentice, T. M. Reynolds, X. W. Shu, M. D. Stritzinger, L. Tartaglia, G. Terreran, L. Tomasella, S. Valenti, G. Valerin, G. J. Wang, X. F. Wang, L. Borsato, E. Callis, G. Cannizzaro, S. Chen, E. Congiu, M. Ergon, L. Galbany, A. Gal-Yam, X. Gao, M. Gromadzki, S. Holmbo, F. Huang, C. Inserra, K. Itagaki, Z. Kostrzewa-Rutkowska, K. Maguire, S. Margheim, S. Moran, F. Onori, A. Sagués Carracedo, K. W. Smith, J. Sollerman, A. Somero, B. Wang, D. R. Young

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

3 Citas (Scopus)

Resumen

We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family of objects similar to the prototypical ILRT SN 2008S. These events have a rise time that is less than 15 days and absolute peak magnitudes of between-11.5 and-14.5 mag. Their pseudo-bolometric light curves peak in the range 0.5-9.0 × 1040 erg s-1 and their total radiated energies are on the order of (0.3-3) × 1047 erg. After maximum brightness, the light curves show a monotonic decline or a plateau, resembling those of faint supernovae IIL or IIP, respectively. At late phases, the light curves flatten, roughly following the slope of the 56Co decay. If the late-time power source is indeed radioactive decay, these transients produce 56Ni masses on the order of 10-4 to 10-3 M⊙. The spectral energy distribution of our ILRT sample, extending from the optical to the mid-infrared (MIR) domain, reveals a clear IR excess soon after explosion and non-negligible MIR emission at very late phases. The spectra show prominent H lines in emission with a typical velocity of a few hundred km s-1, along with Ca II features. In particular, the [Ca II] λ7291,7324 doublet is visible at all times, which is a characteristic feature for this family of transients. The identified progenitor of SN 2008S, which is luminous in archival Spitzer MIR images, suggests an intermediate-mass precursor star embedded in a dusty cocoon. We propose the explosion of a super-asymptotic giant branch star forming an electron-capture supernova as a plausible explanation for these events.

Idioma originalInglés
Número de artículoA157
PublicaciónAstronomy and Astrophysics
Volumen654
DOI
EstadoPublicada - 1 oct. 2021

Áreas temáticas de ASJC Scopus

  • Astronomía y astrofísica
  • Ciencias planetarias y espacial

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