Bibcode
Alonso-Herrero, A.; Ryder, S. D.; Knapen, J. H.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 322, Issue 4, pp. 757-769.
Fecha de publicación:
4
2001
Número de citas
39
Número de citas referidas
30
Descripción
We present high-resolution near-infrared imaging obtained using adaptive
optics and HST/NICMOS, and ground-based spectroscopy of the hotspot
galaxy NGC 2903. Our near-infrared resolution imaging enables us to
resolve the infrared hotspots into individual young stellar clusters or
groups of these. The spatial distribution of the stellar clusters is not
coincident with that of the bright Hii regions, as revealed by the
HST/NICMOS Paα image. Overall, the circumnuclear star formation in
NGC 2903 shows a ring-like morphology with an approximate diameter of
625pc. The star formation properties of the stellar clusters and Hii
regions have been studied using the photometric and spectroscopic
information in conjunction with evolutionary synthesis models. The
population of bright stellar clusters shows a very narrow range of ages,
4-7×106yr after the peak of star formation, or absolute
ages 6.5-9.5×106yr (for the assumed short-duration
Gaussian bursts), and luminosities similar to the clusters found in the
Antennae interacting galaxy. This population of young stellar clusters
accounts for some 7-12per cent of the total stellar mass in the central
625pc of NGC 2903. The Hii regions in the ring of star formation have
luminosities close to that of the supergiant Hii region 30 Doradus, they
are younger than the stellar clusters, and they will probably evolve
into bright infrared stellar clusters similar to those observed today.
We find that the star formation efficiency in the central regions of NGC
2903 is higher than in normal galaxies, approaching the lower end of
infrared luminous galaxies.