A dearth of atomic hydrogen in NGC 1052-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 in the lambda cold dark matter context. In this letter, we present a deep Giant Metrewave Radio Telescope search for atomic hydrogen in this ultra-diffuse galaxy, NGC 1052-DF2. We report a non-detection of the HI 21cm transition from the galaxy and place a stringent upper limit on the HI mass of the galaxy - MHI < 3.15 × 106 (ΔV /20 km/s)1/2 M⊙ (3σ). This makes NGC 1052-DF2 an extremely gas-poor galaxy with an atomic gas to stellar mass fraction of MHI/M* < 0.016 (ΔV /20 km/s)1/2 (3σ). Such low gas fractions are typical of dwarf ellipticals in dense environments and would be consistent with NGC 1052-DF2 having undergone a tidal stripping event which can also explain its apparent lack of dark matter.