A Dearth of Atomic Hydrogen in NGC1052-DF2

TL;DR

This study used GMRT observations to search for atomic hydrogen in the ultra-diffuse galaxy NGC1052-DF2, finding it to be extremely gas-poor, supporting theories of tidal stripping and challenging dark matter presence.

Contribution

First deep HI search in NGC1052-DF2, providing upper limits on atomic gas content and implications for galaxy formation and dark matter theories.

Findings

No HI detected in NGC1052-DF2

HI mass upper limit: < 3.15 x 10^6 M_sun

Gas fraction: < 0.016

Abstract

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 having undergone a tidal stripping event which can also explain its apparent lack of dark matter.