J/ApJ/836/202 Kinematic study of the Leo II dwarf galaxy (Spencer+, 2017)
A multi-epoch kinematic study of the remote dwarf spheroidal galaxy Leo II.
Spencer M.E., Mateo M., Walker M.G., Olszewski E.W.
<Astrophys. J., 836, 202-202 (2017)>
=2017ApJ...836..202S 2017ApJ...836..202S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Photometry, SDSS ; Spectroscopy ;
Radial velocities ; Abundances, [Fe/H] ; Stars, giant
Keywords: galaxies: abundances; galaxies: dwarf;
galaxies: individual: Leo II; galaxies: kinematics and dynamics
Abstract:
We conducted a large spectroscopic survey of 336 red giants in the
direction of the Leo II dwarf galaxy using Hectochelle on the Multiple
Mirror Telescope, and we conclude that 175 of them are members based
on their radial velocities and surface gravities. Of this set, 40
stars have never before been observed spectroscopically. The systemic
velocity of the dwarf is 78.3±0.6km/s with a velocity dispersion of
7.4±0.4km/s. We identify one star beyond the tidal radius of Leo II
but find no signatures of uniform rotation, kinematic asymmetries, or
streams. The stars show a strong metallicity gradient of
-1.53±0.10dex/kpc and have a mean metallicity of -1.70±0.02dex.
Description:
We used the 90prime imager on the 2.3m Bok telescope at Steward
Observatory in Arizona to collect photometry of Leo II. Stars were
observed in the Washington M and I filters during 2006 February.
We calibrated these instrumental M and I magnitudes by transposing
them to apparent g and i magnitudes of the Sloan Digital Sky Survey
(SDSS).
Spectroscopic observations were obtained with the Multiple Mirror
Telescope (MMT) using Hectochelle. Spectra were taken on five
different runs between 2006 and 2013.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 44 9309 Photometric properties of stars in the direction
of Leo II
table3.dat 76 471 Spectroscopic properties of stars in the
direction of Leo II
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See also:
J/MNRAS/360/185 : VI photometry of the Leo II galaxy (Bellazzini+, 2005)
J/A+A/459/423 : VI and [Fe/H] of Fornax dSph RGB stars (Battaglia+, 2006)
J/ApJ/649/201 : Veloc. & Washington photom. in Carina dSph (Munoz+, 2006)
J/AJ/131/2114 : Radial velocities in Fornax dSph (Walker+, 2006)
J/MNRAS/378/318 : Chemical abundances in Leo I and II dSph (Bosler+, 2007)
J/AJ/133/270 : Metallicities and ages in Leo II dSph (Koch+, 2007)
J/AJ/134/566 : Leo II stellar kinematics (Koch+, 2007)
J/MNRAS/388/1185 : JHKs photometry of LeoII dSph giants (Gullieuszik+, 2008)
J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008)
J/ApJ/675/201 : Radial velocities of stars near Leo I (Mateo+, 2008)
J/AJ/137/3100 : Radial velocities of 4 dSph galaxies (Walker+, 2009)
J/ApJS/191/352 : Abundances in stars of MW dwarf satellites (Kirby+, 2010)
J/MNRAS/411/1013 : CaII triplet in Sextans dSph galaxy (Battaglia+, 2011)
J/ApJ/741/100 : Proper motions of Leo II member stars (Lepine+, 2011)
J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)
J/MNRAS/448/2717 : Bayesian analysis of resolved stellar spectra
(Walker+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
13- 22 F10.7 deg DEdeg Declination in decimal degrees (J2000)
24- 28 F5.2 mag gmag [15.9/23.7] The g band magnitude (SDSS system)
30- 33 F4.2 mag e_gmag [0.03/1.6] Uncertainty in gmag
35- 39 F5.2 mag imag [16.9/25.2] The i band magnitude (SDSS system)
41- 44 F4.2 mag e_imag [0.02/1.4] Uncertainty in imag
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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- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 20 F9.6 deg DEdeg Declination in decimal degrees (J2000)
22- 28 F7.2 d HJD Heliocentric Julian Date; JD-2450000
30- 35 F6.2 km/s RVel [-95.2/280.2] Radial velocity (likely members
have 57.7<RVel<101.2km/s)
37- 40 F4.2 km/s e_RVel [0.1/3] Uncertainty in RVel
42- 45 I4 K Teff [4321/7317] Effective temperature
47- 49 I3 K e_Teff [21/975] Uncertainty in Teff
51- 54 F4.2 [cm/s2] log(g) [0.7/5.6] Log surface gravity
56- 59 F4.2 [cm/s2] e_log(g) [0.04/1.4] Uncertainty in log(g)
61- 65 F5.2 [Sun] [Fe/H] [-3.6/1.4] Metallicity
67- 70 F4.2 [Sun] e_[Fe/H] [0.02/1] Uncertainty in [Fe/H]
72 I1 --- Nobs [1/8] Number of observations
74 A1 --- Mm Member of Leo II; "Y"=Yes (289 occurrences;
175 unique sources); or "N"
76 A1 --- Comb Single ("S") or combined ("C") measurement
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Oct-2017