DELIGHT: Deep Learning Identification of Galaxy Hosts of Transients using Multi-resolution Images

TL;DR

DELIGHT is a deep learning algorithm that efficiently identifies galaxy hosts of transients using multi-resolution images, enabling real-time analysis with higher accuracy and less data than traditional methods.

Contribution

The paper introduces DELIGHT, a novel multi-resolution image-based deep learning model for real-time galaxy host identification of transients, outperforming existing methods in accuracy and data efficiency.

Findings

Accurately identifies both large and small host galaxies.

Uses significantly less data than single-resolution approaches.

Reduces catastrophic errors and contamination in host identification.

Abstract

We present DELIGHT, or Deep Learning Identification of Galaxy Hosts of Transients, a new algorithm designed to automatically and in real-time identify the host galaxies of extragalactic transients. The proposed algorithm receives as input compact, multi-resolution images centered at the position of a transient candidate and outputs two-dimensional offset vectors that connect the transient with the center of its predicted host. The multi-resolution input consists of a set of images with the same number of pixels, but with progressively larger pixel sizes and fields of view. A sample of \nSample galaxies visually identified by the ALeRCE broker team was used to train a convolutional neural network regression model. We show that this method is able to correctly identify both relatively large ($10\arcsec < r < 60\arcsec$) and small ($r \le 10\arcsec$) apparent size host galaxies using much less information (32 kB) than with a large, single-resolution image (920 kB). The proposed method has fewer catastrophic errors in recovering the position and is more complete and has less contamination ($< 0.86\%$) recovering the cross-matched redshift than other state-of-the-art methods. The more efficient representation provided by multi-resolution input images could allow for the identification of transient host galaxies in real-time, if adopted in alert streams from new generation of large etendue telescopes such as the Vera C. Rubin Observatory.