Details

Autor(en) / Beteiligte

• Srivastav, Shubham
• Smartt, Stephen J.
• Leloudas, Giorgos
• Huber, Mark E.
• Chambers, Ken
• Malesani, Daniele B.
• Hjorth, Jens
• Gillanders, James H.
• Schultz, A.
• Sim, Stuart A.
• Auchettl, Katie
• Fynbo, Johan P. U.
• Gall, Christa
• McBrien, Owen R.
• Rest, Armin
• Smith, Ken W.
• Wojtak, Radoslaw
• Young, David R.

Titel

The Lowest of the Low: Discovery of SN 2019gsc and the Nature of Faint Iax Supernovae

Ist Teil von

• Astrophysical journal. Letters, 2020-04, Vol.892 (2), p.L24

Ort / Verlag

Austin: The American Astronomical Society

Erscheinungsjahr

2020

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• We present the discovery and optical follow-up of the faintest supernova-like transient known. The event (SN 2019gsc) was discovered in a star-forming host at 53 Mpc by ATLAS. A detailed multicolor light curve was gathered with Pan-STARRS1 and follow-up spectroscopy was obtained with the Nordic Optical Telescope and Gemini-North. The spectra near maximum light show narrow features at low velocities of 3000-4000 km s−1, similar to the extremely low-luminosity SNe 2010ae and 2008ha, and the light curve displays a similar fast decline (Δm15(r) = 0.91 0.10 mag). SNe 2010ae and 2008ha have been classified as SNe Iax, and together the three either make up a distinct physical class of their own or are at the extreme low-luminosity end of this diverse supernova population. The bolometric light curve is consistent with a low kinetic energy of explosion (Ek ∼ 1049 erg s−1), a modest ejected mass (Mej ∼ 0.2 M ), and radioactive powering by 56Ni (MNi ∼ 2 × 10−3 M ). The spectra are quite well reproduced with radiative transfer models (TARDIS) and a composition dominated by carbon, oxygen, magnesium, silicon, and sulfur. Remarkably, all three of these extreme Iax events are in similar low-metallicity star-forming environments. The combination of the observational constraints for all three may be best explained by deflagrations of near MCh hybrid carbon-oxygen-neon white dwarfs that have short evolutionary pathways to formation.