New HI observations of KK 69. Is KK 69 a dwarf galaxy in transition?

TL;DR

This study presents new high-sensitivity HI observations of KK 69, revealing its gas phases, asymmetrical distribution, and signs of interaction with NGC 2683, suggesting KK 69 is a transitional dwarf galaxy undergoing gas stripping.

Contribution

The paper provides detailed HI phase decomposition, maps asymmetrical gas distribution, and identifies signs of interaction and potential galaxy companions, advancing understanding of dwarf galaxy evolution.

Findings

30% of HI gas is in the cold neutral medium phase.

HI distribution is asymmetric and offset from the stellar body.

Evidence of gas stripping due to interaction with NGC 2683.

Abstract

We present new HI data of the dwarf galaxy KK 69, obtained with the Giant Metrewave Radio Telescope (GMRT) with a signal-to-noise ratio that almost double previous observations. We carried out a Gaussian spectral decomposition and stacking methods to identify the cold neutral medium (CNM) and the warm neutral medium (WNM) of the HI gas. We found that 30% of the total HI gas, which corresponds to a mass of approx. 10^7 Mo, is in the CNM phase. The distribution of the HI in KK 69 is not symmetric. Our GMRT HI intensity map of KK 69 overlaid onto a Hubble Space Telescope image reveals an offset of approx. 4 kpc between the HI high-density region and the stellar body, indicating it may be a dwarf transitional galaxy. The offset, along with the potential truncation of the HI body, are evidence of interaction with the central group spiral galaxy NGC 2683, indicating the HI gas is being stripped from KK 69. Additionally, we detected extended HI emission of a dwarf galaxy member of the group as well as a possible new galaxy located near the north-eastern part of the NGC 2683 HI disk.