J/MNRAS/380/281 Faint galactic satellites spectroscopic survey (Martin+, 2007)
A Keck/DEIMOS spectroscopic survey of faint galactic satellites:
searching for the least massive dwarf galaxies.
Martin N.F., Ibata R.A., Chapman S.C., Irwin M., Lewis G.F.
<Mon. Not. R. Astron. Soc., 380, 281-300 (2007)>
=2007MNRAS.380..281M 2007MNRAS.380..281M
ADC_Keywords: Galaxies, photometry ; Spectroscopy ; Radial velocities
Keywords: galaxies: dwarf - galaxies: kinematics and dynamics - Local Group -
dark matter
Abstract:
We present the results of a spectroscopic survey of the recently
discovered faint Milky Way satellites Bootes, Ursa Major I,
Ursa Major II and Willman 1 (Wil1). Using the DEep Imaging
Multi-Object Spectrograph mounted on the Keck II telescope, we have
obtained samples that contain from ∼15 to ∼85 probable members of
these satellites for which we derive radial velocities precise to a
few km/s down to i∼21-22. About half of these stars are observed with
a high enough signal-to-noise ratio to estimate their metallicity to
within ±0.2dex. The characteristics of all the observed stars are
made available, along with those of the Canes Venatici I dwarf galaxy
that have been analysed in a companion paper.
Description:
Target stars were selected for observation from the point sources in
the fourth data release (DR4) of the SDSS. For Boo, CVnI and UMaI, two
DEIMOS masks were observed, slightly offset in declination, whereas
only one field in each of UMaII and Wil1 were observed. Each mask was
observed with three exposures of 1200s with the 1200-lines/mm
grating during the nights of 2006 May 27 and 28.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 96 Derived parameters for stars in the Boo sample
table2.dat 67 127 Derived parameters for stars in the CVnI sample
table3.dat 67 68 Derived parameters for stars in the UMaI sample
table4.dat 67 54 Derived parameters for stars in the UMaII sample
table5.dat 67 48 Derived parameters for stars in the Wil1 sample
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See also:
http://sdss.org : SDSS Home Page
Byte-by-byte Description of file: table?.dat
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Bytes Format Unit Label Explanations
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1- 2 I2 h RAh SDSS right ascension (J2000.0) (1)
4- 5 I2 min RAm SDSS right ascension (J2000.0)
7- 11 F5.2 s RAs SDSS right ascension (J2000.0)
13 A1 --- DE- SDSS declination sign (J2000.0)
14- 15 I2 deg DEd SDSS declination (J2000.0)
17- 18 I2 arcmin DEm SDSS declination (J2000.0)
20- 23 F4.1 arcsec DEs SDSS declination (J2000.0)
25- 29 F5.2 mag gmag SDSS g magnitude
31- 35 F5.2 mag imag SDSS i magnitude
37- 42 F6.1 km/s RV Measured radial velocity
44- 47 F4.1 km/s e_RV rms uncertainty on RV
49- 51 I3 0.1nm-1 S/N Signal-to-noise ratio of the spectrum
(in Å-1)
53- 56 F4.1 [Sun] [Fe/H] ?=- Derived metallicity of Boo members with
S/N>10Å-1
58- 61 F4.1 0.1nm EWCa Weighted sum of the EWs of the three CaI
lines at 8498, 8542 and 8662Å
63- 65 F3.1 0.1nm EWNa Sum of the EWs of the two NaI
lines at 8193 and 8195Å
67 A1 --- Mm [y/n] Status of the stars that were used to
derive the parameters of the dwarf (2)
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Note (1): Objects identified as [MIC2007] JHHMMSS.ss+DDMMSS.s in Simbad
Note (2): None-members (y/n value) have e_RV>15km/s, are aligned with the
Boo CMD features, have [Fe/H]>-1.0, have EWNa>0.8 or are clearly away
from the radial velocity peak produced by the dwarf galaxy.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 21-Dec-2007