J/ApJ/874/138 Gaia and LAMOST DR4 M giant members of Sgr stream (Li+, 2019)
Detecting the Sagittarius stream with LAMOST DR4 M giants and Gaia DR2.
Li J., Liu C., Xue X., Zhong J., Weiss J., Carlin J.L., Tian H.
<Astrophys. J., 874, 138 (2019)>
=2019ApJ...874..138L 2019ApJ...874..138L
ADC_Keywords: Stars, M-type; Stars, giant; Spectra, optical; Radial velocities;
Space velocities; Photometry, infrared; Stars, distances;
Abundances, [Fe/H]; Proper motions
Keywords: galaxies: individual (Sagittarius dSph) ; Galaxy: halo ;
Galaxy: structure ; stars: abundances ; stars: distances ;
stars: late-type
Abstract:
We use LAMOST DR4 M giants combined with Gaia DR2 proper motions and
ALLWISE photometry to obtain an extremely pure sample of Sagittarius
(Sgr) stream stars. Using TiO5 and CaH spectral indices as indicators,
we selected a large sample of M-giant stars from M-dwarf stars in
LAMOST DR4 spectra. Considering the position, distance, proper motion,
and angular momentum distribution, we obtained 164 pure Sgr stream
stars. We find that the trailing arm has higher energy than the
leading arm in the same angular momentum. The trailing arm we detected
extends to a heliocentric distance of ∼130kpc at
Λ☉∼170°, which is consistent with the feature found
in RR Lyrae in Sesar+ (2017, J/ApJ/844/L4). Both of these detections
of Sgr, in M-giants and in RR Lyrae, imply that the Sgr stream may
contain multiple stellar populations with a broad metallicity range.
Description:
In this paper, we map the 6D phase space of M giants from the
Sagittarius (Sgr) stream in LAMOST using LAMOST DR4 (V/153) radial
velocities combined with Gaia DR2 (I/345) proper motions and
ALLWISE (II/328) photometry.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 251 164 The parameters for Sagittarius stream members
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Description of file:
On the FTP, "Sgr_164.fits" is the original table in FITS format.
See also:
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/153 : LAMOST DR4 catalogs (Luo+, 2018)
J/AJ/113/806 : M-Subdwarfs (Gizis 1997)
J/ApJ/508/397 : H-band Spectral Standards (Meyer+ 1998)
J/AJ/125/1598 : New high PM stars in the northern sky (Lepine+, 2003)
J/ApJ/670/346 : M giant stars in the Sagittarius dwarf galaxy. V. (Chou+, 2007)
J/ApJ/753/90 : Stellar param. of K5 and later type Kepler stars (Mann+, 2012)
J/AJ/145/102 : Bright M dwarf spectroscopy in the northern sky (Lepine+, 2013)
J/MNRAS/440/3430 : SDSS-2MASS-WISE stellar colour locus (Davenport+, 2014)
J/other/RAA/15.1154 : M-giant star candidates in LAMOST DR 1 (Zhong+, 2015)
J/ApJS/226/1 : Carbon stars from LAMOST DR2 data (Ji+, 2016)
J/ApJ/823/59 : WISE and 2MASS photometry of M giant stars (Li+, 2016)
J/ApJ/844/L4 : PS1 RRab for tracing outer Virgo overdensity (Sesar+, 2017)
J/AJ/153/204 : RR Lyrae stars from the PS1 3π survey (Sesar+, 2017)
J/ApJS/234/31 : Carbon stars from LAMOST using machine learning (Li+, 2018)
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 (J2000) (ra)
13- 22 F10.7 deg DEdeg Declination (J2000) (dec)
24- 30 F7.3 deg Lambda [63.6/268.4] Λ☉ value (L_v)
32- 40 F9.5 deg B [-14.5/14.8] B☉ value (B_v)
42- 48 F7.4 mag Jmag0 [10.49/15.08] 2MASS J-band magnitude (j0)
50- 56 F7.4 mag Hmag0 [9.59/14.22] 2MASS H-band magnitude (h0)
58- 64 F7.4 mag Ksmag0 [9.22/14.02] 2MASS Ks-band magnitude (k0)
66- 72 F7.4 mag W1mag0 [8.86/14] AllWISE W1-band (3.35um)
magnitude (w10)
74- 80 F7.4 mag W2mag0 [8.9/14.02] AllWISE W2-band (4.6um)
magnitude (w20)
82- 89 F8.3 km/s HRV [-280/163] Heliocentric radial velocity (rv)
91- 98 F8.3 km/s Vgsr [-263/133] Line-of-sight Galactic standard
of rest (GSR) velocity (1)
100-107 F8.4 kpc Dist [20/123.2] Heliocentric distance
109-115 F7.4 [-] [Fe/H] [-5.1/0.8] Metallicity (feh)
117-123 F7.3 --- S/N [5/131] Signal to noise ratio (sn)
125-131 F7.3 kpc Xgc X coordinate (positive toward the Sun) (X_GC)
133-139 F7.3 kpc Ygc Y coordinate (positive in the the direction
of Galactic rotation) (Y_GC)
141-147 F7.3 kpc Zgc Z coordinate (Z_GC)
149-156 F8.3 km/s Vx [-359/197] X Cartesian velocity (V_x)
158-165 F8.3 km/s Vy [-223/152] Y Cartesian velocity (V_y)
167-174 F8.3 km/s Vz [-322/137] Z Cartesian velocity (V_z)
176-181 F6.3 mas/yr pmRA [-2.3/1.3] Gaia DR2 proper motion in RA
183-187 F5.3 mas/yr e_pmRA [0.04/0.7] pmRA uncertainty (pmRA_error)
189-194 F6.3 mas/yr pmDE [-3/-0.1] Gaia DR2 proper motion
in DEC (pmDec)
196-200 F5.3 mas/yr e_pmDE [0.03/0.4] pmDE uncertainty (pmDec_error)
202-211 F10.3 km2/s2 E [-87685/-7501] Energy space (2)
213-221 F9.3 km2/s2 L [481.8/20932] Total angular momentum (2)
223-231 F9.3 km2/s2 Lx [-3523/7844] X-component of angular
momentum (L_x) (2)
233-241 F9.3 km2/s2 Ly [-2811/17311] Y-component of angular
momentum (L_y) (2)
243-251 F9.3 km2/s2 Lz [-9690/9260] Z-component of angular
momentum (L_z) (2)
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Note (1): For each star, we calculated the line-of-sight Galactic standard of
rest velocity from the heliocentric RV using the formula:
Vgsr=RV+10cosl.cosb+225.2sinl.cosb+7.2sinb km/s. See Section 2.3.
Note (2): Based on the Galactocentric (X, Y, Z, Vx, Vy, Vz) and potential
φtot(X, Y, Z), the four integrals of motion (E,L) can be calculated
as follows (Equation 1):
E = 1/2(V2x+V2y+V2z)+φtot(x2+y2+z2)0.5
Lx = YVz-ZVy
Ly = ZVx-XVz
Lz = XVy-YVx
L = (L2x+L2y+L2z)0.5
See Section 2.4 and 3.3.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 31-Aug-2020