J/ApJ/657/241 Spectroscopy of Leo I red giants (Koch+, 2007)
Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy.
Wide-Field implications for galactic evolution.
Koch A., Wilkinson M.I., Kleyna J.T., Gilmore G.F., Grebel E.K.,
MacKey A.D., Evans N.W., Wyse R.F.G.
<Astrophys. J. 657, 241 (2007)>
=2007ApJ...657..241K 2007ApJ...657..241K
ADC_Keywords: Galaxies, nearby ; Stars, giant ; Photometry ; Radial velocities ;
Abundances, [Fe/H]
Keywords: galaxies: abundances - galaxies: dwarf - galaxies: evolution -
galaxies: individual (Leo I) - galaxies: kinematics and dynamics
Abstract:
We present low-resolution spectroscopy of 120 red giants in the
Galactic satellite dwarf spheroidal (dSph) Leo I, obtained with
GeminiN GMOS and Keck DEIMOS. We find stars with velocities consistent
with membership of Leo I out to 1.3 King tidal radii. By measuring
accurate radial velocities with a median measurement error of 4.6km/s,
we find a mean systemic velocity of 284.2km/s with a global velocity
dispersion of 9.9km/s. The dispersion profile is consistent with
being flat out to the last data point.
Description:
One part of our observations was carried out in queue mode with the
Gemini Multiobject Spectrograph (GMOS) at the 8m Gemini North
telescope, Hawaii, over four nights between 2004 December and 2005
January. The other part of our data was obtained with the Deep Imaging
Multi-Object Spectrograph (DEIMOS) at the 10m Keck II telescope. Leo I
was observed on the DEIMOS multislit spectrograph on the Keck II
telescope on 2005 February 6-8.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 81 128 Characteristics of the target stars
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 A1 --- Samp [GD] GMOS or DEIMOS sample identification
3- 7 I5 --- [KWK2007] Identification number
9- 10 I2 h RAh Hour of Right Ascension (J2000)
12- 13 I2 min RAm Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 31 F5.2 arcsec DEs Arcsecond of Declination (J2000)
33- 37 F5.2 mag Imag The I band magnitude
39- 42 F4.2 mag V-I The (V-I) color index
44- 48 F5.2 arcmin Rad Distance from LeoI center
50- 55 F6.2 km/s HRV Heliocentric radial velocity (2)
57- 61 F5.2 km/s e_HRV Error in HRV
63- 67 F5.2 --- R Tonry-Davis R-based error of HRV
69- 70 I2 --- S/N Signal-to-noise
72- 76 F5.2 [-] Fe/H ? Metallicity on Carretta & Gratton scale (3)
78- 81 F4.2 [-] e_Fe/H ? Error in Fe/H
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Note (2): The velocities from both the GMOS and DEIMOS samples have been
shifted to a common mean
Note (3): On the reference scale of Carretta & Gratton (1997,
Cat. J/A+AS/121/95).
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History:
* 06-Jan-2009: From electronic version of the journal
* 31-Mar-2009: More accurate positions kindly supplied by the
author (Andreas Koch); original positions were accurate
to 1s in RA and 1arcsec in Dec only.
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 06-Jan-2009