| |
 |
| Paper: |
VLA H53α and H92α Line Observations of Central Region of NGC253 |
| Volume: |
375, From Z-Machines to ALMA: (Sub)Millimeter Spectroscopy of Galaxies |
| Page: |
279 |
| Authors: |
Rodriguez-Rico, C.A. |
| Abstract: |
We present new Very Large Array (VLA) observations toward NGC253 of the radio recombination line (RRL) H53α (43GHz) at an angular resolution of 1.″5 &3215; 1.″0. The free-free emission at 43GHz is estimated to be ∼ 140mJy, implying a star formation rate of ∼ 2MSolar yr−1 in the nuclear region of this starburst galaxy. A reanalysis is made of previously reported H92α observations carried out with angular resolutions of 1.″5 × 1.″0 and 0.&38243;36 × 0.″21. Based on the line and continuum emission models used for the 1.″5×1.″0 angular resolution observations, the RRLs H53α and H92α are tracers of the high-density (∼ 105 cm−3) and low-density (∼ 103 cm−3) thermally ionized gas components in NGC253, respectively. The velocity gradient in the central ∼ 18 pc of the NE component, as observed in both the H53α and H92α lines, is in the opposite direction from the velocity gradient determined from the CO observations. The enclosed virial mass, as deduced from the H53α velocity gradient over the NE component, is ∼ 5 × 106MSolar in the central ∼ 18 pc region. The H92α line observations at high angular resolution (0.″36 × 0.″21) reveal a large velocity gradient, along a P.A. ∼ −45° in the NE component, of ∼ 110 kms−1 arcsec−1. The dynamical mass estimated using the high angular resolution H92α data (∼ 7 × 106MSolar) supports the existence of an accreted massive object in the nuclear region of NGC253. A complete version of this paper has been published as Rodriguez-Rico et al. (2006). |
|
|
|
|
|
