Introducing the Condor Array Telescope. II. Deep imaging observations of the edge-on spiral galaxy NGC 5907 and the NGC 5866 Group: yet another view of the iconic stellar stream

TL;DR

This study uses deep imaging with the Condor Array Telescope to analyze the NGC 5907 stellar stream, revealing its morphology, potential progenitors, and possible dark matter subhalo interactions, challenging previous claims and providing new insights.

Contribution

The paper presents detailed deep imaging observations of the NGC 5907 stellar stream, clarifying its structure and morphology, and identifying new features and potential progenitors not previously reported.

Findings

The stellar stream is a single curved structure 220 kpc long.

No evidence of a progenitor galaxy remnant in the eastern stream.

Detection of a possible bifurcation and a gap in the western stream.

Abstract

We used the Condor Array Telescope to obtain deep imaging observations through the luminance filter of the entirety of the NGC 5866 Group, including a very extended region surrounding the galaxy NGC 5907 and its stellar stream. We find that the stellar stream consists of a single curved structure that stretches $220$ kpc from a brighter eastern stream to a fainter western stream that bends to the north and then curls back toward the galaxy. This result runs contrary to a previous claim of a second loop of the stellar stream but is consistent with another previous description of the overall morphology of the stream. We further find that: (1) an extension of the western stream appears to bifurcate near its apex, (2) there is an apparent gap of $\approx 6$ kpc in the western stream due east of the galaxy, (3) contrary to a previous claim, there is no evidence of the remnant of a progenitor galaxy within the eastern stream, although (4) there are many other possible progenitor galaxies, (5) there is another structure that, if it is at the distance of the galaxy, stretches 240 kpc and contains two very large, very low-surface-brightness "patches" of emission, one of which was noted previously and another of which was not. We note the number and variety of stellar streams in the vicinity of NGC 5907 and the apparent gap in the western stream, which may be indicative of a dark subhalo or satellite in the vicinity of the galaxy.