The curious case of J113924.74+164144.0: a possible new group of galaxies at z = 0.0693

TL;DR

This study investigates a galaxy with tidal features at z=0.069, using HI observations to explore potential interactions and the possibility of a new galaxy group formation.

Contribution

First HI observations of a galaxy with tidal features at z=0.069, revealing signs of interaction and suggesting a loose galaxy group.

Findings

Detected extended HI emission from the galaxy with tidal features.

No HI emission detected from the neighboring spiral galaxy.

Identified a potential galaxy group at z ~ 0.069.

Abstract

J113924.74+164144.0 is an interesting galaxy at z = 0.0693, i.e. D_L ~ 305 Mpc, with tidal-tail-like extended optical features on both sides. There are two neighbouring galaxies, a spiral galaxy J113922.85+164136.3 which has a strikingly similar 'tidal' morphology, and a faint galaxy J113923.58+164129.9. We report HI 21 cm observations of this field to search for signatures of possible interaction. Narrow HI emission is detected from J113924.74+164144.0, but J113922.85+164136.3 shows no detectable emission. The total HI mass detected in J113924.74+164144.0 is 7.7 x 10^9 M_solar. The HI emission from the galaxy is found to be extended and significantly offset from the optical position of the galaxy. We interpret this as signature of possible interaction with the neighbouring spiral galaxy. There is also a possible detection of HI emission from another nearby galaxy J113952.31+164531.8 at z = 0.0680 at a projected distance of 600 kpc, and with a total HI mass of 5.3 x 10^9 M_solar, suggesting that all these galaxies form a loose group at z ~ 0.069.