Revisiting the formation history of the minor-axis dust lane galaxy NGC 1947

Spavone, M.; Iodice, E.; Calvi, R.; Bettoni, D.; Galletta, G.; Longo, G.; Mazzei, P.; Minervini, G.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 393, Issue 1, pp. 317-328.

Advertised on:
2
2009
Number of authors
8
IAC number of authors
0
Citations
11
Refereed citations
10
Description
In this paper, we present a detailed study of the peculiar early-type galaxy NGC 1947. The main goal of this work is to constrain the dynamical status and the formation history of NGC 1947 by comparing the observed properties with the predictions derived from different galaxy formation scenarios. To this aim, we derived the photometric and kinematical properties of NGC 1947. Due to the presence of an extended dust lane, which crosses the galaxy centre along the photometric minor axis, we used near-infrared (NIR) images (J and K bands) to derive an accurate analysis of the stellar light distribution. Optical images (in the V and R bands) are used to derive the colour profiles and colour maps to study the structure of the dust lane. The observed kinematics confirm the presence of two components with decoupled angular momentum: gas and dust rotate along the minor axis, while the rotation velocities of the stars are observed along the major axis. The complex structure observed in NGC 1947 supports the hypothesis that some kind of interactions happened in the evolution of this object. We analysed two alternatives: a merging process and an accretion event. We discussed how the observed properties strongly suggest that the decoupled ring of gas and dust has been accreted from outside.