Circumnuclear star formation in the barred galaxy NGC 1022.
Abstract
Observations of ring like structures around the compact nucleus of a bar galaxy are useful for determining whether the structure is at the expected location of a resonance and also whether there is star formation in them. We observed the barred spiral galaxy NGC 1022 in the radio continuum at 20, 6, and 2 cm, in CO(1 -0) and CO(2-1) and in the near infrared J, H and K bands. No evidence was found for a circumnuclear ring like structure either from our radio continuum or our CO observations. Radio continuum emission is only detected from the central 20" of the galaxy, in a compact core and a weaker second component to the north. The spectral indices of the integrated fluxes at the three wavelengths are flatter than an average disk spectral index, α_disk_~-0.75, namely α^6^_20_=-0.52, α^2^_20_= - 0.23 and α^2^_6_= - 0.03. From our millimeter observations we estimate a molecular hydrogen mass within a diameter of 3.3 kpc of 1 10^9^ M_sun_. The observed near-infrared colors are J - H = 0.82 and H - K = 0.35. From our observations with an aperture of 14", together with smaller aperture observations by Devereux et al. we estimate a mass within 200 pc of 2 10^9^ M_sun_.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 1991
- Bibcode:
- 1991A&A...252...19G
- Keywords:
-
- Barred Galaxies;
- Galactic Structure;
- Star Formation;
- Compact Galaxies;
- Galactic Nuclei;
- Astrophysics