2005A&A...431..127T


Query : 2005A&A...431..127T

2005A&A...431..127T - Astronomy and Astrophysics, volume 431, 127-142 (2005/2-3)

Thick disks and halos of spiral galaxies M 81, NGC 55 and NGC 300.

TIKHONOV N.A., GALAZUTDINOVA O.A. and DROZDOVSKY I.O.

Abstract (from CDS):

By using images from the HST/WFPC2/ACS archive, we have analyzed the spatial distribution of the AGB and RGB stars along the galactocentric radius of nearby spiral galaxies M 81, NGC 300 and NGC 55. Examining color-magnitude diagrams and stellar luminosity functions, we gauge the stellar contents of the surroundings of the three galaxies. The red giant population (RGB) identified at large galactocentric radii yields a distance of 3.85±0.08Mpc for M 81, 2.12±0.10Mpc for NGC 55, and 2.00±0.13Mpc for NGC 300, and a mean stellar metallicity of -0.65, -1.25, and -0.87 respectively. We find that there are two number density gradients of RGB stars along the radius, which correspond to the thick disk and halo components of the galaxies. We confirm the presence of a metallicity gradient of evolved stars in these galaxies, based on the systematic changes of the color distribution of red giant stars. These results imply that the thick disk might be a general feature of spiral galaxies, and endorse a further investigation of the outer stellar edges of nearby spirals, which is critical in constraining the origin and evolution of galaxies.

Abstract Copyright:

Journal keyword(s): galaxies: individual: M 81 - galaxies: individual: NGC 55 - galaxies: individual: NGC 300 - galaxies: stellar content - galaxies: photometry - galaxies: structure

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 NGC 55 GiG 00 14 53.602 -39 11 47.86 8.54 8.58 7.87 7.84   ~ 774 2
2 NGC 300 GiG 00 54 53.4465638304 -37 41 03.168402396 8.83 8.69 8.13 7.46   ~ 1485 2
3 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1656 2
4 NGC 2976 GiP 09 47 15.458 +67 54 58.97 11.77 11.03 10.16 9.51   ~ 666 1
5 LEDA 28529 G 09 53 48.8 +68 58 09   18.89       ~ 90 1
6 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4419 3
7 UGC 5336 AG? 09 57 32.8632 +69 02 50.735 15.19 15.15 14.10 14.12   ~ 312 4
8 NGC 3077 GiP 10 03 19.0965510921 +68 44 01.556166166 11.23 10.85 10.14 9.74   ~ 768 0
9 NAME Garland G 10 03 43.1 +68 41 32           ~ 62 2
10 NGC 4244 GiG 12 17 29.659 +37 48 25.60   10.71   9.99   ~ 556 1
11 IC 5052 G 20 52 01.633 -69 11 35.93 12.83 12.20 11.66 11.40   ~ 152 0

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