The Carnegie Supernova Project II. Observations of the intermediate luminosity red transient SNhunt120

Abstract

We present multi-wavelength observations of two gap transients followed by the Carnegie Supernova Project-II and supplemented with data obtained by a number of different programs. Here in the first of two papers, we focus on the intermediate luminosity red transient (ILRT) designated SNhunt120, while in a companion paper we examine the luminous red novae AT 2014ej. Our data set for SNhunt120 consists of an early optical discovery, estimated to be within 3 days after outburst, the subsequent optical and near-infrared broadband followup extending over a $\sim$2 month period, two visual- and two near-infrared wavelength spectra, and Spitzer Space Telescope observations extending from early ($+$28 d) to late ($+$1155 d) phases. SNhunt120 resembles other ILRTs such as NGC 300-2008-OT and SN 2008S, and like these other ILRTs, SNhunt120 exhibits prevalent mid-infrared emission at both early and late phases. From the comparison of SNhunt120 and other ILRTs to electron-capture supernova simulations, we find that the current models underestimate the explosion kinetic energy and thereby produce synthetic light curves that over-estimate the luminosity. Finally, examination of pre-outburst Hubble Space Telescope images yields no progenitor detection.

Paper 1 of a series of 2. Eight pages of text, 14 figures, and 10 tables. Replaced to match the version published on A&A

References in corpus (17)

• Binary interaction dominates the evolution of massive stars
• HyperLEDA. III. The catalogue of extragalactic distances
• Observational constraints on the progenitors of core-collapse supernovae : the case for missing high mass stars
• The Supernova Channel of Super-AGB Stars
• Super and massive AGB stars - IV. Final fates - Initial to final mass relation
• A New Class of Luminous Transients and A First Census of Their Massive Stellar Progenitors
• The Carnegie Supernova Project I: Third Photometry Data Release of Low-Redshift Type Ia Supernovae and Other White Dwarf Explosions
• The 2008 Luminous Optical Transient in the Nearby Galaxy NGC 300
• An Intermediate Luminosity Transient in NGC300: The Eruption of a Dust-Enshrouded Massive Star
• SN 2008S: A Cool Super-Eddington Wind in a Supernova Impostor
• A very faint core-collapse supernova in M85
• Remnants and ejecta of thermonuclear electron-capture supernovae: Constraining oxygen-neon deflagrations in high-density white dwarfs
• Electron-capture supernovae exploding within their progenitor wind
• A Spitzer/IRS Spectrum of the 2008 Luminous Transient in NGC 300: Connection to Proto-Planetary Nebulae
• The transitional gap transient AT 2018hso: new insights on the luminous red nova phenomenon
• The Carnegie Supernova Project II. Observations of the intermediate luminosity red transient SNhunt120
• Observations of the Optical Transient in NGC 300 with AKARI/IRC: Possibilities of Asymmetric Dust Formation

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