J/AJ/131/332 Velocities of individual stars in NGC 205 (Geha+, 2006)
Local Group dwarf elliptical galaxies.
I. Mapping the dynamics of NGC 205 beyond the tidal radius.
Geha M., Guhathakurta P., Rich R.M., Cooper M.C.
<Astron. J., 131, 332-342 (2006)>
=2006AJ....131..332G 2006AJ....131..332G
ADC_Keywords: Radial velocities ; Galaxies, nearby ; Stars, giant
Keywords: galaxies: dwarf - galaxies: individual (NGC 205) -
galaxies: interactions - galaxies: kinematics and dynamics
Abstract:
NGC 205 is the nearest example of a dwarf elliptical galaxy and
the prototype of this enigmatic galaxy class. Photometric evidence
suggests that NGC 205, a close satellite of the M31 galaxy, is tidally
interacting with its parent galaxy. We present stellar radial velocity
measurements out to a projected radius of 20' (5kpc) in NGC 205 based
on Keck DEIMOS multislit spectroscopic observations of 725 individual
red giant branch stars. Our kinematic measurements extend from the
center out to 6 times the effective radius of NGC 205, well past the
expected tidal radius. The contamination in our kinematic sample from
M31 field stars is estimated to be a few percent based on maximum
likelihood fits to the distribution of stars in position-velocity
space.
Description:
Four multislit masks were observed on the nights of 2003 September 30
and October 1 with the Keck II 10m telescope and DEIMOS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 64 725 Velocity measurements for individual stars in NGC 205
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See also:
J/AJ/112/1438 : NGC 205 BVRI photometry (Lee, 1996)
J/AJ/125/3037 : RI photometry of NGC 205 carbon stars (Demers+, 2003)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- [GGR2006] NGC 205 star designation (1)
8- 9 I2 h RAh Hour of Right Ascension (J2000) (1)
11- 12 I2 min RAm Minute of Right Ascension (J2000) (1)
14- 17 F4.1 s RAs Second of Right Ascension (J2000) (1)
19 A1 --- DE- Sign of the Declination (J2000) (1)
20- 21 I2 deg DEd Degree of Declination (J2000) (1)
23- 24 I2 arcmin DEm Arcminute of Declination (J2000) (1)
26- 29 F4.1 arcsec DEs Arcsecond of Declination (J2000) (1)
31- 34 F4.1 mag Imag The I band magnitude (1)
36- 39 F4.2 mag R-I The (R-I) color index (1)
41- 46 F6.1 km/s HRV Heliocentric radial velocity
48- 51 F4.1 km/s e_HRV Error in HRV (2)
53- 57 F5.1 --- S/N Median per pixel S/N value (3)
59- 64 A6 --- Mask Mask identification (4)
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Note (1): Taken from Demers et al. (2003, private communication).
Note (2): Determined from measurement overlaps for each mask as discussed
in Section 2.4.
Note (3): In the wavelength range 8000-9000Å and refer the reader to
Gilbert et al. (2006, in press) for a discussion of velocity
errors for individual slitlets based on the S/N.
Note (4): Table 2: Keck DEIMOS multislit mask observing parameters
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Mask RA DE PA texp Nslit Useful
Name (J2000.0) (deg) (s) spectra
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N205-1 00 40 27.4 +41 41 30.5 0 3600 184 91%
N205-2 00 39 50.5 +41 48 41.8 -45 3600 185 85%
N205-3 00 40 53.0 +41 40 53.0 -45 3600 193 84%
N205-4 00 40 27.4 +41 41 30.5 0 3600 320 88%
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 02-Nov-2006