J/ApJ/711/361 Local Group dE galaxies. II. (Geha+, 2010)
Local Group dwarf elliptical galaxies.
II. Stellar kinematics to large radii in NGC 147 and NGC 185.
Geha M., van der Marel R.P., Guhathakurta P., Gilbert K.M., Kalirai J.,
Kirby E.N.
<Astrophys. J., 711, 361-373 (2010)>
=2010ApJ...711..361G 2010ApJ...711..361G
ADC_Keywords: Stars, giant ; Radial velocities ; Photometry, VRI ;
Galaxies, nearby
Keywords: galaxies: dwarf - galaxies: individual (NGC 147, NGC 185) -
galaxies: kinematics and dynamics
Abstract:
We present kinematic and metallicity profiles for the M 31 dwarf
elliptical (dE) satellite galaxies NGC 147 and NGC 185. The profiles
represent the most extensive spectroscopic radial coverage for any dE
galaxy, extending to a projected distance of 8 half-light radii
(8reff∼14'). We achieve this coverage via Keck/DEIMOS multislit
spectroscopic observations of 520 and 442 member red giant branch
stars in NGC 147 and NGC 185, respectively. In contrast to previous
studies, we find that both dEs have significant internal rotation. We
measure a maximum rotational velocity of 17±2km/s for NGC 147 and
15±5km/s for NGC 185. The velocity dispersions decrease gently with
radius with average dispersions of 16±1km/s and 24±1km/s for NGC
147 and NGC 185, respectively. The average metallicities for NGC 147
and NGC 185 are [Fe/H]=-1.1±0.1 and [Fe/H]=-1.3±0.1, respectively;
both dEs have internal metallicity dispersions of 0.5dex, but show no
evidence for a radial metallicity gradient.
Description:
Individual stars in NGC 147 and NGC 185 were targeted for spectroscopy
according to their probability of being a RGB star based on
Canada-France-Hawaii Telescope (CFHT) CFH12K mosaic imaging in the R
and I bands.
The data were taken with the Keck II 10 m telescope and the DEIMOS
spectrograph, covering a wavelength region 6400-9100Å. Four
multislit masks were observed in NGC 147 on the nights of 2005 August
28 and September 5-7. Five masks were observed in NGC 185 on 2006
September 16. The spectral resolution, taking into account the
anamorphic distortion, is 1.37Å (FWHM, equivalent to 47km/s at the
CaII triplet).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 54 520 Keck/DEIMOS velocity measurements for NGC 147
table7.dat 54 442 Keck/DEIMOS Velocity Measurements for NGC 185
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See also:
B/cfht : Log of CFHT Exposures (CADC, 1979-)
J/A+A/532/A78 : Long-period variables in NGC 147 and NGC 185 (Lorenz+, 2011)
J/A+A/445/69 : JHK' photometry of C stars in NGC 147 (Sohn+, 2006)
J/A+A/437/61 : Near-IR photometry of AGB stars in NGC 185 (Kang+, 2005)
J/A+A/418/33 : RI photometry of C stars in NGC 147 (Battinelli+, 2004)
J/A+A/417/479 : RI photometry of NGC 185 carbon stars (Battinelli+, 2004)
J/A+A/403/93 : Photometry of AGB stars in NGC 185 and NGC 147 (Nowotny+, 2003)
J/AJ/113/1001 : Stellar photometry in NGC 147 (Han+ 1997)
J/AJ/106/964 : BVRI photometry of NGC 185 stellar population (Lee+, 1993)
Byte-by-byte Description of file: table[67].dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/520] Running index number within the galaxy
5- 9 I5 --- Name Uniq source identification number
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 20 F4.1 s RAs Second of Right Ascension (J2000)
22 A1 --- DE- Sign of the Declination (J2000)
23- 24 I2 deg DEd Degree of Declination (J2000)
26- 27 I2 arcmin DEm Arcminute of Declination (J2000)
29- 32 F4.1 arcsec DEs Arcsecond of Declination (J2000)
34- 37 F4.1 mag Imag Apparent CFHT I-band magnitude
39- 42 F4.2 mag R-I The (R-I) color index
44- 49 F6.1 km/s HRV Heliocentric radial velocity
51- 54 F4.1 km/s e_HRV Error in HRV
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History:
From electronic version of the journal
References:
Geha et al. Paper I. 2006AJ....131..332G 2006AJ....131..332G Cat. J/AJ/131/332
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 03-Apr-2012