Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-01-20
Astrophys.Space Sci.324:341-342,2009
Astronomy and Astrophysics
Astrophysics
4 pages, proceeding of the meeting "Young massive star clusters - Initial conditions and environments", Granada, Spain, 2007
Scientific paper
10.1007/s10509-009-0091-x
(Abbr.) We present high resolution (R~20000) spectra in the blue and the far red of cicumnuclear star-forming regions (CNSFRs) in three early type spirals (NGC3351, NGC2903 and NGC3310) which have allowed the study of the kinematics of stars and ionized gas in these structures and, for the first time, the derivation of their dynamical masses for the first two. In some cases these regions, about 100 to 150 pc in size, are seen to be composed of several individual star clusters with sizes between 1.5 and 4.9 pc estimated from Hubble Space Telescope (HST) images. The stellar dispersions have been obtained from the Calcium triplet (CaT) lines at $\lambda\lambda$ 8494,8542,8662 \AA, while the gas velocity dispersions have been measured by Gaussian fits to the H$\beta$ and [OIII] $\lambda\lambda$ 5007 \AA lines on the high dispersion spectra. Values of the stellar velocity dispersions are between 30 and 68 km/s. We apply the virial theorem to estimate dynamical masses of the clusters, assuming that systems are gravitationally bounded and spherically symmetric, and using previously measured sizes. The measured values of the stellar velocity dispersions yield dynamical masses of the order of 10$^7$ to 10$^8$ solar masses for the whole CNSFRs. Stellar and gas velocity dispersions are found to differ by about 20 to 30 km/s with the H$\beta$ emission lines being narrower than both the stellar lines and the [OIII] $\lambda\lambda$ 5007 \AA lines. The twice ionized oxygen, on the other hand, shows velocity dispersions comparable to those shown by stars, in some cases, even larger. We have found indications of the presence of two different kinematical components in the ionized gas of the regions...
Cardaci Monica V.
Diaz Angeles I.
Hagele Guillermo F.
Terlevich Elena
Terlevich Roberto
No associations
LandOfFree
Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-384467