Star formation in bulgeless late type galaxies: clues to their evolution
arXiv:1205.1936 · doi:10.1111/j.1365-2966.2012.21120.x
Abstract
We present GMRT 1280 MHz radio continuum observations and follow-up optical studies of the disk and nuclear star formation in a sample of low luminosity bulgeless galaxies. The main aim is to understand bulge formation and overall disk evolution in these late type galaxies. We detected radio continuum from five of the twelve galaxies in our sample; the emission is mainly associated with disk star formation. Only two of the detected galaxies had extended radio emission; the others had patchy disk emission. In the former two galaxies, NGC3445 and NGC4027, the radio continuum is associated with star formation triggered by tidal interactions with nearby companion galaxies. We did follow-up Halpha imaging and nuclear spectroscopy of both galaxies using the Himalayan Chandra Telescope (HCT). The Halpha emission is mainly associated with the strong spiral arms. The nuclear spectra indicate ongoing nuclear star formation in NGC3445 and NGC4027 which maybe associated with nuclear star clusters. No obvious signs of AGN activity were detected. Although nearly bulgeless, both galaxies appear to have central oval distortions in the R band images; these could represent pseudobulges that may later evolve into large bulges. We thus conclude that tidal interactions are an important means of bulge formation and disk evolution in bulgeless galaxies; without such triggers these galaxies appear to be low in star formation and overall disk evolution.
12 pages, 14 figures, to appear in MNRAS
References in corpus (14)
- The GALEX Ultraviolet Atlas of Nearby Galaxies
- Dynamics of Barred Galaxies
- Multiwavelength study of massive galaxies at z~2. II. Widespread Compton thick AGN and the concurrent growth of black holes and bulges
- The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei
- Radial variation of attenuation and star formation in the largest late-type disks observed with GALEX
- The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey: Interaction-Induced Star Formation in the Mid-Infrared
- FIR colours of nearby late-type galaxies in the Herschel Reference Survey
- An Accreting Black Hole in the Nuclear Star Cluster of the Bulgeless Galaxy NGC 1042
- Dark matter dominance at all radii in the superthin galaxy UGC 7321
- The dark matter halos of the bluest low surface brightness galaxies
- A Chandra view of NGC 3621: a bulgeless galaxy hosting an AGN in its early phase?
- The nature of late-type spiral galaxies: structural parameters, optical and near-infrared colour profiles, and dust extinction
- Multi-wavelength Study of Young Massive Star Clusters in the Interacting Galaxy ARP 24
- AGN Activity and Black Hole Masses in Low Surface Brightness Galaxies