The Remarkable 60 x 2 kpc Optical Filament Associated with a Poststarburst Galaxy in Coma Cluster

TL;DR

This paper reports the discovery of an exceptionally long and narrow Halpha emitting filament in the Coma Cluster, associated with a poststarburst galaxy, exploring its possible origins.

Contribution

It presents the first detailed observation of a 60 kpc optical filament linked to a poststarburst galaxy in the Coma Cluster, and discusses potential formation mechanisms.

Findings

Detected a 60 kpc long, narrow Halpha filament in the Coma Cluster.

The filament shares the same redshift as the galaxy D100.

Possible origins include gas stripping from a dwarf galaxy or D100 by ram pressure.

Abstract

In the deep narrow band image of the Coma Cluster taken with Suprime-Cam of the Subaru telescope, we found an extremely long and narrow (~ 60 kpc x 2 kpc) Halpha emitting region associated with a poststarburst galaxy (D100). Follow up spectroscopy shows that the region has the same redshift as D100. The surface brightness of the region is typically 25 mag(AB) arcsec^-2 in Halpha, which corresponds to 0.5--4x10^-17 erg s^-1 cm^-2 arcsec^-2. We set two possible explanations for the origin of the region; gas stripped off from a merged dwarf, or gas stripped off from D100 by ram pressure. Either scenario has difficulty to fully explain all the observed characteristics of the region.