Revealing Dusty Supernovae in High-Redshift (Ultra-)Luminous InfraRed Galaxies Through Near-Infrared Integrated Light Variability

TL;DR

This study introduces a novel infrared variability technique to detect supernovae in dusty, high-redshift (U)LIRGs, leveraging long-term Spitzer and Herschel data to identify supernovae indirectly through integrated light changes.

Contribution

The paper proposes and demonstrates a new method for detecting supernovae in high-redshift dusty galaxies via integrated infrared light variability, suitable for future JWST observations.

Findings

Identified supernova candidates through light curve analysis.

Validated the method's ability to distinguish supernovae from AGN activity.

Showed potential for probing nuclear regions of distant galaxies.

Abstract

Luminous and ultra-luminous infrared galaxies ((U)LIRGs) are rare today but are increasingly abundant at high redshifts. They are believed to be dusty starbursts, and hence should have high rates of supernovae (multiple events per year). Due to their extremely dusty environment, however, such supernovae could only be detected in restframe infrared and longer wavelengths, where our current facilities lack the capability of finding them individually beyond the local universe. We propose a new technique for higher redshifts, which is to search for the presence of supernovae through the variability of the integrated rest-frame infrared light of the entire hosts. We present a pilot study to assess the feasibility of this technique. We exploit a unique region, the "IRAC Dark Field" (IDF), that the Spitzer Space Telescope has observed for more than 14 years in 3--5 micron. The IDF also has deep far-infrared data (200--550 micron) from the Herschel Space Observatory that allow us to select high-redshift (U)LIRGs. We obtain a sample of (U)LIRGs that have secure optical counterparts, and examine their light curves in 3--5 micron. While the variabilities could also be caused by AGNs, we show that such contaminations can be identified. We present two cases where the distinct features in their light curves are consistent with multiple supernovae overlapping in time. Searching for supernovae this way will be relevant to the James Webb Space Telescope (JWST) to probe high-redshift (U)LIRGs into their nuclear regions where JWST will be limited by its resolution.