Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000aas...19711104r&link_type=abstract
American Astronomical Society, 197th AAS Meeting, #111.04; Bulletin of the American Astronomical Society, Vol. 32, p.1591
Astronomy and Astrophysics
Astronomy
Scientific paper
Using the VLT with FORS1 and ISAAC we resolve stars in the halo and NE shell of the nearest giant elliptical galaxy NGC 5128. The shell is likely to be the stellar debris of a smaller galaxy accreted by NGC 5128 approximately 160 to 500 Myr ago (Quinn 1984, ApJ, 297, 596; Israel 1998, A&ARv, 8, 237). We indeed observe a higher stellar density at the position of the shell. On the shell a string of young blue stars is superimposed (see also Graham 1998, ApJ, 502, 245 and Mould et al. 2000, ApJ, 536, 266). Comparison of our UV color-magnitude diagram (CMD) with the theoretical isochrones of the Padua group gives an age of 10-15 Myr for this recent star formation. The bluest stars (U-V<-0.75) are mainly aligned with the direction of the radio and X-ray jet, but there is also a vertical structure located at the edge of the large HI cloud found next to the shell (Schiminovich 1994, ApJ, 432, L101). The optical (U-V) and near-IR (V-Ks) CMDs for the rest of the shell stars are consistent with an old population similar to the one observed in the halo field of NGC 5128. The halo population of NGC 5128 is mainly old and has a significant metallicity spread. The optical-near IR (V-Ks) CMDs reveal stars as metal-poor as [Fe/H] ~-2 dex. Unfortunately, the incompleteness in the V-band photometry prevents the determination of the upper end of the metallicity distribution. At the assumed distance of 3.6 Mpc (Soria et al. 1996, ApJ, 465, 79), the K-band magnitude of the tip of the RGB is expected to be found at K ~21. We observe a large number of stars between 19.5 and 21 mag in Ks, corresponding to a significant intermediate-age AGB population. This work was partially sponsored by FONDECYT grants No. 07990048 and 01990440.
Bedding Tim
Rejkuba Marina
Silva Ronaldo Da
~Minniti Dante
No associations
LandOfFree
Stellar populations of the recent merger NGC 5128 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 Stellar populations of the recent merger NGC 5128, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar populations of the recent merger NGC 5128 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1728035