Interstellar Gas in the NGC 4410 Galaxy Group

Abstract

We present new radio continuum, 21 cm HI, and 2.6 mm CO data for the peculiar radio galaxy NGC 4410A and its companion NGC 4410B, and compare with available optical and X-ray maps. Our radio continuum maps show an asymmetric double-lobedstructure, with a high surface brightness lobe extending 3.6 arcmin (~100 kpc) to the southeast and a 6.2 arcmin (~180 kpc) low surface brightness feature in the northwest. Molecular gas is abundant in NGC 4410A, with M(H2) ~ 4 X 10^9 M(sun) (using the standard Galactic conversion factor), but is undetected in NGC 4410B. HI is less abundant, with M(HI) ~ 10^9 M(sun) for the pair. Our HI map shows a 3 X 10^8 M(sun) HI tail extending 1.7 arcmin (50 kpc) to the southeast of the pair, coincident with a faint optical tail and partially overlapping with the southeastern radio lobe. The HI tail is anti-coincident with a 2' (56 kpc) long X-ray structure aligned with a stellar bridge that connects the pair to a third galaxy. If this X-ray emission is associated with the group, there is 3 - 8 X 10^8 M(sun) of hot gas in this feature: either intracluster gas or shocked gas associated with the bridge. Our detection of abundant interstellar gas in this pair suggests that the distortions in this lobe map have been caused by the interstellar medium in this system. The interaction of the two galaxies and the subsequent motion of the interstellar medium in the system relative to the jet may have produced sufficient ram pressure to bend the radio jet. An alternative hypothesis is that the jet was distorted by ram pressure due to an intracluster medium, although the small radial velocity of NGC 4410A relative to the group and the lack of diffuse X-ray emission in the group makes this less likely unless the group is not virialized or is in the process of merging with another group.Comment: 12 pages, Latex, 8 figures (some multiple panels); figures 4a and 4b are color; Astrophysical Journal, in pres

BVRIphotometric analysis for the galaxy group NGC 4410

“…The group of galaxies NGC 4410 is a peculiar group of twelve galaxies with velocities in the range 6900−7500 km s −1 (Smith 2000) with four components in obvious interaction: NGC 4410 A-D (Figs. 1−3).…”

“…• 17 40 , J2000.0) has been classified as a Sab pec asymmetric double-lobed radio-galaxy (Hummel et al 1986;Tschöcke et al 1999;Smith 2000), with the radio emission interpreted as a distorted radio jet. This galaxy forms a galaxy pair and, most probably, a future merger (Smith 2000;Donahue et al 2002;Smith et al 2003) with the E?…”

“…This galaxy forms a galaxy pair and, most probably, a future merger (Smith 2000;Donahue et al 2002;Smith et al 2003) with the E? pec or S0?…”

“…pec galaxy (Hummel et al 1986;Smith 2000) NGC 4410B. This galaxy pair (NGC 4410A/B) has two diffuse optical filaments, one at the NW of NGC 4410A and the other at SE of NGC 4410B (Hummel et al 1986;Smith 2000), and a tidal bridge connecting with NGC 4410C, a S0? type (Smith 2000).…”

“…This galaxy pair (NGC 4410A/B) has two diffuse optical filaments, one at the NW of NGC 4410A and the other at SE of NGC 4410B (Hummel et al 1986;Smith 2000), and a tidal bridge connecting with NGC 4410C, a S0? type (Smith 2000). In this galaxy pair, there are some optical knots visible in our color maps situated near the NGC 4410A nucleus and classified as H II regions (Donahue et al 2002).…”