2003A&A...407..541D


C.D.S. - SIMBAD4 rel 1.7 - 2021.04.12CEST23:21:26

2003A&A...407..541D - Astronomy and Astrophysics, volume 407, 541-549 (2003/8-4)

Galactic structure studies with BATC star counts.

DU C., ZHOU X., MA J., CHEN A.B.-C., YANG Y., LI J., WU H., JIANG Z. and CHEN J.

Abstract (from CDS):

We report the first results of star counts carried out with the National Astronomical Observatories (NAOC) 60/90cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000Å in the BATC survey. We analyze a sample of over 1400 main sequence stars (14≤V≤21), which lie in the field with central coordinates RA=09h53m13.30s and Dec=47°49'00.0'' (J2000) (Galactic coordinates: l=169.95°, b=49.80°). The field of view is 0.95deg2, and the spatial scale was 1.67''. Since star counts at high galactic latitudes are not strongly related to the radial distribution, they are well suited to study the vertical distribution of the Galaxy. In our model, the distribution of stars perpendicular to the plane of the Galaxy is given by two exponential disks (thin disk plus thick disk) and a de Vaucouleurs halo. Also, based on star counts, we derive the scale heights of the thin disk to be 320+14–15pc and of the thick disk to be 640+30–32pc, respectively, with a local density of 7.0±1% of the thin disk. The errors of scale heights and the corresponding space number density normalization are estimated at a 68% confidential level. The density law for the Galactic halo population is also investigated. We find that the observed counts support an axial ratio of c/a≤0.6 for a de Vaucouleurs r1/4 law, implying a more flattened halo. We consider that it is possible that the halo has two subpopulations-a flattened inner halo and a spherical outer halo in the Milky Way, and such a halo model might resolve many of the divergences in star count results. We also derive the stellar luminosity function (SLF) for the thin disk, and it partly agrees with the Hipparcos luminosity function.

Abstract Copyright:

Journal keyword(s): Galaxy: structure - stars: luminosity function, mass function

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 SA 68- reg 00 17 28 +15 53.2           ~ 52 0
2 HD 19445 PM* 03 08 25.5884 +26 19 51.400 8.29 8.52 8.06 7.60 7.27 G2VFe-3 746 0
3 HD 84937 PM* 09 48 56.09801 +13 44 39.3237 8.49 8.68 8.32 7.97 7.70 F8Vm-5 734 0
4 SA 57- reg 13 08 38 +29 23.1           ~ 177 0
5 BD+26 2606 SB* 14 49 02.3550036151 +25 42 09.136461939 9.92 10.16 9.73 9.27 8.95 A5 357 0
6 BD+17 4708 SB* 22 11 31.3751899315 +18 05 34.158392398 9.73 9.91 9.46 9.03 8.70 sdF8 545 0

    Equat.    Gal    SGal    Ecl

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2021.04.12-23:21:26

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