Rapidly evolving transients in the Dark Energy Survey. Issue 1 (29th August 2018)

• Record Type: Journal Article
• Authors: Pursiainen, M; Childress, M; Smith, M; Prajs, S; Sullivan, M; Davis, T M; Foley, R J; Asorey, J; Calcino, J; Carollo, D; Curtin, C; D'Andrea, C B; Glazebrook, K; Gutierrez, C; Hinton, S R; Hoormann, J K; Inserra, C; Kessler, R; King, A; Kuehn, K; Lewis, G F; Lidman, C; Macaulay, E; Möller, A; Nichol, R C; Sako, M; Sommer, N E; Swann, E; Tucker, B E; Uddin, S A; Wiseman, P; Zhang, B; Abbott, T M C; Abdalla, F B; Allam, S; Annis, J; Avila, S; Brooks, D; Buckley-Geer, E; Burke, D L; Carnero Rosell, A; Carrasco Kind, M; Carretero, J; Castander, F J; Cunha, C E; Davis, C; De Vicente, J; Diehl, H T; Doel, P; Eifler, T F; Flaugher, B; Fosalba, P; Frieman, J; García-Bellido, J; Gruen, D; Gruendl, R A; Gutierrez, G; Hartley, W G; Hollowood, D L; Honscheid, K; James, D J; Jeltema, T; Kuropatkin, N; Li, T S; Lima, M; Maia, M A G; Martini, P; Menanteau, F; Ogando, R L C; Plazas, A A; Roodman, A; Sanchez, E; Scarpine, V; Schindler, R; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Tucker, D L; Walker, A R;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 481:Issue 1(2018)
• Page Start: 894
• Page End: 917
• Publication Date: 2018-08-29
• Subjects: supernovae: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty2309
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present the results of a search for rapidly evolving transients in the Dark Energy Survey Supernova Programme. These events are characterized by fast light-curve evolution (rise to peak in ≲10 d and exponential decline in ≲30 d after peak). We discovered 72 events, including 37 transients with a spectroscopic redshift from host galaxy spectral features. The 37 events increase the total number of rapid optical transients by more than a factor of two. They are found at a wide range of redshifts (0.05 < $z$ < 1.56) and peak brightnesses (−15.75 > M g > −22.25). The multiband photometry is well fit by a blackbody up to few weeks after peak. The events appear to be hot ( T ≈ 10 000–30 000 K) and large ( R ≈ 10 14 − 2 × 10 15 cm) at peak, and generally expand and cool in time, though some events show evidence for a receding photosphere with roughly constant temperature. Spectra taken around peak are dominated by a blue featureless continuum consistent with hot, optically thick ejecta. We compare our events with a previously suggested physical scenario involving shock breakout in an optically thick wind surrounding a core-collapse supernova, we conclude that current models for such a scenario might need an additional power source to describe the exponential decline. We find that these transients tend to favour star-forming host galaxies, which could be consistent with a core-collapse origin. However, more detailed modelling of the light curves is necessary to determine their physical origin.