@misc{10481/63670, year = {2020}, month = {7}, url = {http://hdl.handle.net/10481/63670}, abstract = {We present multiwavelength observations of two gap transients that were followed by the Carnegie Supernova Project-II. The observations are 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 three days after outburst, the subsequent optical and near-infrared broadband followup extending over a period of about two months, 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 midinfrared 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 overestimate the luminosity. Finally, examination of pre-outburst Hubble Space Telescope images yields no progenitor detection.}, organization = {USA's NSF AST-0306969 AST-0607438 AST-1008343 AST-1613426 AST-1613455 AST-1613472}, organization = {Danish Agency for Science and Technology and Innovation}, organization = {Independent Research Fund Denmark (IRFD) 8021-00170B}, organization = {VILLUM FONDEN 13261}, organization = {Science Foundation Ireland}, organization = {European Union (EU) 754513}, organization = {Aarhus University Research Foundation}, organization = {National Science Foundation (NSF) AST1613455}, organization = {Texas A&M University Mitchell/Heep/Munnerlyn Chair in Observational Astronomy}, organization = {European Union (EU) 839090}, organization = {European Union (EU) PGC2018-095317-B-C21}, organization = {Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1191038}, organization = {Ministry of Economy, Development, and Tourism's Millennium Science Initiative IC120009}, organization = {Catania University 55722062134}, publisher = {EDP Sciences}, keywords = {Supernovae: individual: SNhunt120}, keywords = {Supernovae: general}, title = {The Carnegie Supernova Project II Observations of the intermediate-luminosity red transient SNhunt120}, doi = {10.1051/0004-6361/202038018}, author = {Stritzinger, M. D. and Galbany González, Lluis}, }