J/AJ/112/1438 NGC 205 BVRI photometry (Lee 1996)
Stellar populations in the central region of the dwarf elliptical galaxy NGC 205
Lee M.G.
<Astron. J. 112, 1438 (1996)>
=1996AJ....112.1438L 1996AJ....112.1438L (SIMBAD/NED BibCode)
ADC_Keywords: Populations, stellar ; Galaxies, photometry ; Photometry, CCD
Abstract:
BVRI/CCD photometry of ∼2,300 stars in the central 2.2'x3.5' area of
the dwarf elliptical galaxy NGC205 in the Local Group is presented.
The color-magnitude diagrams of NGC 205 show: (1) a blue plume around
(B-V)∼0.0mag, extending up to V∼19.3mag (MV~-5.4mag); and (2) a
strong asymptotic giant branch (AGB) population, the brightest of
which reaches I∼19.0mag, 1.5 mag brighter than the tip of the red
giant branch. BVRI photometry of three globular clusters (Hubble IV.
V, and VI) is also presented. Hubble V is much bluer [(B-V)=0.37]
than other globular clusters. This blue color of Hubble V leads to an
estimate of the age, ∼300Myrs. A V luminosity function for the blue
stars has been derived: the logarithmic slope of the luminosity
function for -5.7<MV←3.2 is 0.64±0.12, which is similar to those
of other nearby galaxies. The AGB stars extend to Mbol~-5.7mag, which
is ∼0.7mag brighter than those in NGC 185. The bolometric luminosity
function of the AGB stars in NGC 205 is found to be flatter than that
of the similar dwarf elliptical galaxy NGC 185, but similar to that of
a bulge field 4' of the nucleus of M31. Surface photometry for the
central area within R=50" is presented, showing that the colors get
bluer as the galactocentric radius decreases except for the nucleus
region within R=1.6" where the colors get redder inward. Star
formation history in NGC 205 is briefly discussed.
Objects:
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RA (2000) DE Designation(s)
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00 40.3 +41 41 NGC 205 = M 110
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 48 218 BVRI CCD photometry of the bright stars with
V<21.5mag in NGC 205
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Star number
6- 10 F5.1 pix Xpos X position (1)
12- 17 F6.1 pix Ypos Y position (1)
19- 23 F5.2 mag Vmag V magnitude
24 A1 --- u_Vmag Uncertainty flag on Vmag
25- 29 F5.2 mag B-V ? B-V colour index
30 A1 --- u_B-V Uncertainty flag on B-V
31- 35 F5.2 mag V-R ? V-R colour index
36 A1 --- u_V-R Uncertainty flag on V-R
37- 41 F5.2 mag (V-I) ? (V-I) colour index
42 A1 --- u_(V-I) Uncertainty flag on (V-I)
43- 47 F5.2 mag Imag ? I magnitude
48 A1 --- u_Imag Uncertainty flag on Imag
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Note (1): 1 pix = 0.205". X increases from left to right, Y from top to down.
The center of the nucleus of NGC 205
(1950) RA=00h37m38.7s, DE=+41°24'44" is at x=343, y=475.
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Table 4: Mean photometric errors vs V and I for NGC 205.
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V e_V e_B-V e_V-I I e_I e_V-I
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20.25 0.04 0.05 0.07 18.75 0.03 0.08
20.75 0.06 0.08 0.12 19.25 0.04 0.10
21.25 0.08 0.12 0.11 19.75 0.06 0.13
21.75 0.11 0.16 0.14 20.25 0.09 0.16
22.25 0.16 0.21 0.19 20.75 0.23 0.20
22.75 0.22 0.27 0.25 21.25 0.25 0.25
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History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 17-Jun-1997