Pairing Optical and Atomic Hydrogen Detections to Assess Newly-Discovered Galaxy Candidates

Abstract

As optical telescopes become more advanced, their detections begin to unveil very faint, previously unobserved extragalactic objects in the night sky – some of which could be among the smallest and most diffuse galaxies ever discovered. Many of the objects detected appear to be comprised of young, blue stars which seem to exist in isolation from any parent galaxies. In this research, we attempt to connect the very faint optical detections with atomic hydrogen, HI, detections from archival surveys, in order to assess the likelihood that they are newly-discovered galaxies and whether they are actively forming stars. Using the Systematically Measuring Ultra-diffuse Galaxies (SMUDGes) catalog to generate a list of potential candidates, the HI profile corresponding to each candidate’s coordinates was generated and smoothed, ensuring the detection of subtle emissions. Out of the 48 candidates analyzed, 2 very promising candidates emerged and properties like the object’s recessional velocity and HI mass were determined. While the lack of emissions detected may point to radio surveys not being deep enough to detect subtle HI emissions, observing these successful candidates may allow for the formation, origins and evolution of these objects to be studied, thus expanding our knowledge of the universe and galaxy formations.