Physical conditions in the nuclei of spiral galaxies. II. Photometric and spectroscopic observations of the nuclei of southern spiral galaxies.
Abstract
Summary. In this paper, we present new spectroscopic and photometric measurements on the central regions of southern spiral galaxies. The photometric observations give the fluxes through narrow interference filters, four of which apply to the continuum, while three are specifically set up for the emission lines [Oii] 3726-29 A, HP 4861 A and [Oiii] 4959-5007 A. A detailed study of these filters has been made, in order to give an absolute and precise determination of flux. Eleven galactic nuclei were observed differentially with comparison stars, which were subsequently calibrated against Hayes standard stars. Spectroscopic results were added, in order to assess precisely the information content passed by each filter, and to obtain the profiles of the emission lines. As a by-product we give also the computed UBV data for the comparison stars and also for the galactic nuclei: in this case, the UB V data is free from the emission line contribution and refers only to the continuous energy distribution. All results are uncorrected for reddening (by the object itself and by the Galaxy). Key words: nuclei of galaxies - photometry - spectroscopy - southern hemisphere
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 1974
- Bibcode:
- 1974A&A....33..331A