The Arecibo Galaxy Environment Survey. Iii. Observations Toward the Galaxy Pair NGC 7332/7339 and the Isolated Galaxy NGC 1156

Abstract

Two 5 square degree regions around the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156 have been mapped in the 21-cm line of neutral hydrogen (H i) with the Arecibo L-band Feed Array out to a redshift of ∼ 0.065 (∼ 20000 km s −1 ) as part of the Arecibo Galaxy Environment Survey. One of the aims of this survey is to investigate the environment of galaxies by identifying dwarf companions and interaction remnants; both of these areas provide the potential for such discoveries. The neutral hydrogen observations were complemented by optical and radio follow-up observations with a number of telescopes. A total of 87 galaxies were found, of which 39 (45 per cent) were previously cataloged and 15 (17 per cent) have prior redshifts. Two dwarf galaxies have been discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity NGC 1156 . A parallel optical search of the area revealed one further possible dwarf galaxy near NGC 7332.

The Arecibo Galaxy Environment Survey – X. The structure of halo gas around M33

“…The observations and data reduction techniques are described in depth in Auld et al (2006), and also in Cortese et al (2008), Minchin et al (2010) and Davies et al (2011). Therefore, they have only been summarised here.…”

The Arecibo Galaxy Environment Survey IX: the isolated galaxy sample

“…It is dubious whether, given its projected distance from UGC 2082 and its separation in radial velocity, it is actually a companion of UGC 2082; we err on the side of including it in our analysis as a companion as this sets a lower limit on the significance of differences between our isolated galaxy sample and HIMFs from other regions (see next section). The companion of NGC 1156, referred to here as NGC 1156A, is a new detection by AGES, previously reported by Minchin et al (2010) as AGES J030039+254656.…”

“…All three fields were observed with the Arecibo L-band Feed Array (ALFA) in the standard AGES manner, as described by Auld et al (2007), Cortese et al (2008) and Minchin et al (2010). Observations were carried out in -5 (NGC 1156), 2009-10 (UGC 2082.…”

“…Observations were carried out in -5 (NGC 1156), 2009-10 (UGC 2082. Data for all three fields were taken with the WAPP correlators using the standard AGES setup Cortese et al 2008;Minchin et al 2010).…”

“…NGC 1156 is an irregular galaxy at a recessional velocity of 379 km s −1 . AGES observations of this galaxy and the surrounding region were reported in and in Minchin et al (2010). As in the earlier paper, we adopt the distance estimate of 7.8 Mpc from Karachentsev et al (2006).…”