Spectroscopic observations of southern nearby galaxies
| Autor: | E. Agüero, E. Bajaja, S. Paolantonio |
|---|---|
| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Astronomy and Astrophysics Supplement Series. 136:179-187 |
| ISSN: | 1286-4846 0365-0138 |
| DOI: | 10.1051/aas:1999459 |
| Popis: | The galaxy NGC 2442 was observed with a REOSC spectrograph, installed in the 2.15 m CASLEO telescope, in order to derive galactic parameters from the observed optical lines and to compare them with the re- sults of radioastronomical observations made in the con- tinuum, at 843 MHz, with the MOST and in the CO lines with the SEST telescope. Recent publications allowed us to extend the comparison to results from interferomet- ric observations of H and H i 21 cm lines and of the continuum at 1415 MHz. The long slit observations were made placing the 5: 8 slit at six dierent positions on the optical image of the galaxy. The emission line intensity ratios at the nuclear region indicate that NGC 2442 is a LINER. The electron temperature and volume density are Te 14 000 K and Ne 530 cm 3 , respectively. In contrast, a spectrum of a region 87 00 to the NE shows the typical characteristics of a H ii region. In this case Te 6 500 K and Ne 10 cm 3 . Good correlations between the distributions of intensities, velocity elds and rotation curves have been found for the optical and radio lines. It is shown that the three intensity peaks along the line at PA = 40 were not resolved by the observations at ra- dio frequencies. The steep central rotation curve seen in CO has been conrmed and improved showing the exis- tence of a disc or a ring, with a radius of 12: 00 5, rotating at 216/sin(i )k m s 1 . Two velocity components in three optical spectra obtained in the nuclear region, have been related to two small H regions close to the nucleus and to the central ring. Asymmetries in the distributions of the |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|