A Dearth of Atomic Hydrogen in NGC1052-DF2

Aditya Chowdhury

Published 2018-10-11Version 1

The recently claimed discovery of an ultra-diffuse galaxy lacking dark matter has important implications for alternate theories to dark matter as well as models of galaxy formation within the $\Lambda$CDM context. In this letter, we present a deep Giant Metrewave Radio Telescope (GMRT) search for atomic hydrogen in this ultra-diffuse galaxy, NGC1052-DF2. We report a non-detection of the HI21cm transition from the galaxy and place a stringent upper-limit on the HI mass of the galaxy - $M_{HI} < 3.15 \times 10^6 \ ({\Delta V}/20 \ \textrm{km/s})^{1/2} \ M_\odot \ (3\sigma)$. This makes NGC1052-DF2 an extremely gas poor galaxy with an atomic gas to stellar mass fraction of $M_{HI}/M_* \ < \ 0.016 \ ({\Delta V}/20 \ \textrm{km/s})^{1/2} \ (3\sigma)$. Such low gas fractions are typical of dwarf ellipticals in dense environments and would be consistent with NGC1052-DF2 being a tidal dwarf, a scenario that can explain its apparent lack of dark matter.