J/ApJ/933/151 Member stars of TriAnd, ACS and MRi in the MW (Zhang+, 2022)
The substructures in the anticenter region of the Milky Way.
Zhang Z., Shi W.B., Chen Y.Q., Zhao G., Carrell K., Zhang H.P.
<Astrophys. J., 933, 151 (2022)>
=2022ApJ...933..151Z 2022ApJ...933..151Z
ADC_Keywords: Associations, stellar; Stars, giant; Optical; Space velocities;
Abundances, [Fe/H]; Radial velocities; Proper motions
Keywords: Stellar streams ; Galaxy structure
Abstract:
We investigated the observational properties of Triangulum-Andromeda
(TriAnd), Monoceros Ring (MRi), and Anti-Center Stream (ACS) in the
anticenter region using K giants, M giants, and RGB stars from LAMOST
and SDSS survey. The Friends of Friends algorithm was applied to
select member stars of these structures. We found a new spur of TriAnd
at l∼133deg based on member stars selected in this work and compiled
from the literature. The distributions of radial velocity and proper
motion of its member stars indicate that TriAnd is gradually moving
away from the Sun. The comparisons of [Fe/H] and [α/Fe] between
TriAnd and thick-disk/halo stars reveal that TriAnd is likely to
originate from the thick disk. MRi and ACS are adjacent in space with
a boundary around latitude 30deg, and there is no significant
difference between the two structures in velocity, proper motions, and
orbits. We suggested that MRi and ACS probably have a common origin.
We made projections of the four structures in three-dimensional space
for the exploration of the movements between the Sagittarius (Sgr)
stellar stream and MRi, and found that a new spur was formed by the
Sgr stream members in the velocity distribution as it passed through
the MRi region.
Description:
The spectral data used in this work comes from the Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST) and from the Sloan
Digital Sky Survey (SDSS). Our work uses a sample of the combination
of LAMOST DR5 and SDSS DR9. We first select the red giant branch (RGB)
in the SDSS DR9.
The radial velocities of LAMOST and SDSS spectral data had been
calibrated according to the measured values of the high-resolution
spectra, and it shows no systematic deviation between the two data
sets. Therefore, in this work, we took the sample data of LAMOST as
the main source of metallicities and calibrated the SDSS data
accordingly. We finally obtain the sample stars with spatial position,
distance, metallicity, velocity, and proper motion. See section 2.2
To obtain distances, 3 different methods are used depending on the
type of star (RGB, K-giants or M-giants). To get proper motion, the
existing three types of stars are cross-matched with Gaia DR2 with a
radius of 1". See section 2.1
Objects:
---------------------------------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------------------------------
--- --- TriAnd = NAME Triangulum-Andromeda Region
--- --- ACS = NAME Anticenter Stream
--- --- MRi = NAME Monoceros Stream = NAME Monoceros Ring
---------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 143 128 Member stars of TriAnd
table3.dat 137 32 Member stars of ACS
table4.dat 142 132 Member Stars of MRi
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/ApJ/588/824 : Velocities of blue stars near (l,b)=(198,-27) (Yanny+, 2003)
J/A+A/548/A66 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
J/ApJ/751/130 : SDSS-DR7 red HB stars spectroscopic data (Shi+, 2012)
J/ApJ/795/52 : Red giant star sample from SDSS (Chen+, 2014)
J/ApJ/793/62 : Triangulum-Andromeda stellar properties (Sheffield+, 2014)
J/ApJ/794/60 : SDSS RGB stars distances (Tan+, 2014)
J/ApJ/798/110 : Equivalent widths of LAMOST metal-poor stars (Li+, 2015)
J/ApJ/816/80 : The SEGUE K giant survey. III. Galactic halo (Janesh+, 2016)
J/ApJ/823/59 : WISE and 2MASS photometry of M giant stars (Li+, 2016)
J/ApJ/859/L8 : Properties of TriAnd stars (Hayes+, 2018)
J/ApJ/854/47 : RRab of Monoceros Ring & A13 overdensities (Sheffield+, 2018)
J/ApJ/877/13 : Member stars of the GD-1 tidal stream (Huang+, 2019)
J/ApJ/874/138 : Gaia and LAMOST DR4 M giant members of Sgr stream (Li+, 2019)
J/ApJS/245/34 : Abundances for 6 million stars from LAMOST DR5 (Xiang+, 2019)
J/ApJ/880/65 : LAMOST K giants in Galactic halo substructures (Yang+, 2019)
J/ApJS/246/9 : Stellar parameters of LAMOST stars using SLAM (Zhang+, 2020)
J/ApJ/910/46 : Galactic anticenter substructure stars from LAMOST (Li+, 2021)
J/A+A/646/A99 : Gaia DR2 Monoceros and ACS candidates (Ramos+, 2021)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/128] Sequential number
5- 10 F6.3 deg RAdeg Right Ascension, decimal degrees (J2000)
12- 17 F6.3 deg DEdeg Declination, decimal degree (J2000)
19- 23 F5.2 kpc Dist [11.7/25.1] Heliocentric distance
25- 31 F7.2 km/s HRV [-169/-31.9] Heliocentric radial velocity
33- 38 F6.2 deg GLON Galactic Longitude
40- 45 F6.2 deg GLAT Galactic Latitude
47- 51 F5.2 [-] [Fe/H] [-1.54/0.54] Log of Fe/H abundance
53- 58 F6.2 kpc Xgc Galactic coordinate, X (G1)
60- 64 F5.2 kpc Ygc Galactic coordinate, Y (G1)
66- 70 F5.2 kpc Zgc Galactic coordinate, Z (G1)
72- 77 F6.2 km/s Vgsr [0.9/103] Galactic standard of rest velocity
79- 84 F6.3 mas/yr pmGLON Proper motion in galactic longitude
86- 91 F6.3 mas/yr pmGLAT Proper motion in galactic latitude
93- 99 F7.2 kpc.km/s L [3519/6554] Angular momentum
101-109 F9.2 km2/s2 E [-97282/-67169] Energy
111-118 F8.4 kpc Xgc2 Arrow's end point galactic coordinate, X
in Fig 15 (G1)
120-126 F7.4 kpc Ygc2 Arrow's end point galactic coordinate, Y
in Fig 15 (G1)
128-135 F8.5 kpc Zgc2 Arrow's end point galactic coordinate, Z
in Fig 15 (G1)
137-143 A7 --- Type Classification of star (1)
--------------------------------------------------------------------------------
Note (1): The member stars selected contain three types as follows:
K-giant = 111 occurrences
M-giant = 15 occurrences
RGB = red giant branch; 2 occurrences
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/32] Sequential number
4- 10 F7.3 deg RAdeg Right Ascension, decimal degrees (J2000)
12- 17 F6.3 deg DEdeg Declination, decimal degree (J2000)
19- 23 F5.2 kpc Dist [7.4/12.6] Heliocentric distance
25- 29 F5.2 km/s HRV [-1.8/30.1] Heliocentric radial velocity
31- 35 F5.2 [-] [Fe/H] [-1.06/-0.43] Log of Fe/H abundance
37- 42 F6.2 deg GLON Galactic Longitude
44- 48 F5.2 deg GLAT Galactic Latitude
50- 55 F6.2 kpc Xgc Galactic coordinate, X (G1)
57- 61 F5.2 kpc Ygc Galactic coordinate, Y (G1)
63- 66 F4.2 kpc Zgc Galactic coordinate, Z (G1)
68- 72 F5.2 km/s Vgsr [-3/72.6]Galactic standard of rest velocity
74- 78 F5.3 mas/yr pmGLON Proper motion in galactic longitude
80- 85 F6.3 mas/yr pmGLAT Proper motion in galactic latitude
87- 93 F7.2 kpc.km/s L [3067/4255] Angular momentum
95-104 F10.2 km2/s2 E [-106557/-89631] Energy
106-113 F8.4 kpc Xgc2 Arrow's end point galactic coordinate, X
in Fig 15 (G1)
115-121 F7.5 kpc Ygc2 Arrow's end point galactic coordinate, Y
in Fig 15 (G1)
123-129 F7.5 kpc Zgc2 Arrow's end point galactic coordinate, Z
in Fig 15 (G1)
131-137 A7 --- Type Classification of star (1)
--------------------------------------------------------------------------------
Note (1): The member stars selected contain two types as follows:
K-giant = 22 occurrences
RGB = red giant branch; 10 occurrences
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/132] Sequential number
5- 11 F7.3 deg RAdeg Right Ascension, decimal degrees (J2000)
13- 18 F6.3 deg DEdeg Declination, decimal degree (J2000)
20- 24 F5.2 kpc Dist [9.9/20.1] Heliocentric distance
26- 31 F6.2 km/s HRV [-67/105] Heliocentric radial velocity
33- 38 F6.2 deg GLON Galactic Longitude
40- 44 F5.2 deg GLAT Galactic Latitude
46- 50 F5.2 [-] [Fe/H] [-1.25/-0.05] Log of Fe/H abundance
52- 57 F6.2 kpc Xgc Galactic coordinate, X (G1)
59- 63 F5.2 kpc Ygc Galactic coordinate, Y (G1)
65- 68 F4.2 kpc Zgc Galactic coordinate, Z (G1)
70- 75 F6.2 km/s Vgsr [-48/66.4] Galactic standard of rest velocity
77- 82 F6.3 mas/yr pmGLON Proper motion in galactic longitude
84- 89 F6.3 mas/yr pmGLAT Proper motion in galactic latitude
91- 97 F7.2 kpc.km/s L [3543/5522] Angular momentum
99-107 F9.2 km2/s2 E [-98486/-76046] Energy
109-116 F8.4 kpc Xgc2 Arrow's end point galactic coordinate, X
in Fig 15 (G1)
118-126 F9.6 kpc Ygc2 Arrow's end point galactic coordinate, Y
in Fig 15 (G1)
128-134 F7.5 kpc Zgc2 Arrow's end point galactic coordinate, Z
in Fig 15 (G1)
136-142 A7 --- Type Classification of star (1)
--------------------------------------------------------------------------------
Note (1): The member stars selected contain two types as follows:
K-giant = 123 occurrences
M-giant = 9 occurrences
--------------------------------------------------------------------------------
Global notes:
Note (G1): Xgc, Ygc, and Zgc are the coordinates of stars and the starting point
coordinates of the arrows in Figure 15. Xgc2, Ygc2, and Zgc2 are the
end point coordinates of the arrows in Figure 15.
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History:
From electronic version of the journal
Acknowledgements:
Weibin Shi [swb at nao.cas.cn]
(End) Katia van der Woerd [CDS] 06-Sep-2024