A Dearth of Atomic Hydrogen in NGC1052-DF2

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 - $M_{HI}<3.15\times 10^6(\Delta V/20\text{km/s}{)}^{1/2}{M}_{\odot }(3\sigma )$. This makes NGC1052-DF2 an extremely gas poor galaxy with an atomic gas to stellar mass fraction of $M_{HI}/M_{\ast }<0.016(\Delta V/20\text{km/s}{)}^{1/2}(3\sigma )$. 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.

4 pages, 2 figures; updated to match version published in MNRAS letters