MeerKAT HI imaging of the jellyfish galaxy ESO 137-001

TL;DR

This paper presents MeerKAT HI observations of the jellyfish galaxy ESO 137-001, revealing extensive gas stripping, a large HI tail, and insights into its star formation and gas depletion times during ram pressure interaction.

Contribution

First HI detection in both disc and outer regions of ESO 137-001, demonstrating advanced gas stripping and detailed analysis of its gas content and star formation.

Findings

ESO 137-001 has lost 90% of its initial HI mass.

A 40 kpc HI tail coincides with multi-wavelength tails.

HI depletion time is 0.29 Gyr, consistent with normal spiral galaxies when considering total gas.

Abstract

We present MeerKAT HI observations of ESO 137-001, a quintessential jellyfish galaxy with long multi-phase tails formed due to the interaction with the intra-cluster medium of its host galaxy cluster, ACO 3627. Our observations reveal the presence of HI in both the disc and outer regions of the galaxy for the first time, with a total HI mass of ($3.5 \pm\ 0.4) \times 10^{8}$ M$_{\odot}$. ESO 137-001 is at an advanced stage of gas stripping; it is extremely HI deficient and seems to have lost 90% of its initial HI mass; about 2/3 of the surviving HI is found at a larger radius than expected for a normal HI disc and forms a $\sim40$ kpc tail coincident with the tail detected at other wavelengths. Only $\sim10$% of the surviving HI is still found within the stellar disc, consistent with the expectation of an outside-in truncation due to ram pressure. Similarly to other jellyfish galaxies, ESO137-001 has a high star formation rate for the low amount of HI detected. We measure an HI depletion time of 0.29 Gyr. However, when taking into account the total gas (HI + H$_2$) content, the depletion time is consistent with typical values measured in nearby spiral galaxies. This suggests that ESO 137-001 is at its current stage of ram pressure interaction characterised by an efficient HI stripping, rather than an enhanced conversion of HI to H$_2$, which was recently observed in some other jellyfish galaxies.