J/A+A/653/A143 A2A catalog of 21000 bulge stars from ARGOS survey (Wylie+, 2021)
A2A: 21 000 bulge stars from the ARGOS survey with stellar parameters on the
APOGEE scale.
Wylie S.M., Gerhard O.E., Ness M.K., Clarke J.P., Freeman K.C.,
Bland-Hawthorn J.
<Astron. Astrophys., 653, A143 (2021)>
=2021A&A...653A.143W 2021A&A...653A.143W (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Spectroscopy ; Radial velocities ; Abundances
Keywords: stars: abundances - stars: fundamental parameters -
Galaxy: abundances - Galaxy: bulge - Galaxy: formation -
methods: data analysis
Abstract:
Aims. Spectroscopic surveys have by now collectively observed tens of
thousands of stars in the bulge of our Galaxy. However, each of these
surveys had unique observing and data processing strategies that led
to distinct stellar parameter and abundance scales. Because of this,
stellar samples from different surveys cannot be directly combined.
Methods. Here we use the data-driven method, The Cannon, to bring
21000 stars from theARGOS bulge survey, including 10000 red clump
stars, onto the parameter and abundance scales of the cross-Galactic
survey,APOGEE, obtaining rms precisions of 0.10dex, 0.07dex, 74K, and
0.18dex for [Fe/H], [Mg/Fe], Teff, and log(g), respectively. The
re-calibratedARGOS survey - which we refer to as the A2A survey - is
combined with theAPOGEE survey to investigate the abundance structure
of the Galactic bulge.
Results. We find X-shaped [Fe/H] and [Mg/Fe] distributions in the
bulge that are more pinched than the bulge density, a signature of its
disk origin. The mean abundance along the major axis of the bar varies
such that the stars are more [Fe/H]-poor and [Mg/Fe]-rich near the
Galactic centre than in the outer bulge and the long bar region. The
vertical [Fe/H] and [Mg/Fe] gradients vary between the inner bulge and
the long bar, with the inner bulge showing a flattening near the plane
that is absent in the long bar. The [Fe/H] - [Mg/Fe] distribution
shows two main maxima, an '[Fe/H]-poor [Mg/Fe]- rich' maximum and an
'[Fe/H]-rich [Mg/Fe]-poor' maximum, that vary in strength with
position in the bulge. In particular, the outer long bar close to the
Galactic plane is dominated by super-solar [Fe/H], [Mg/Fe]-normal
stars. Stars composing the [Fe/H]-rich maximum show little kinematic
dependence on [Fe/H], but for lower [Fe/H] the rotation and dispersion
of the bulge increase slowly. Stars with [Fe/H]←1dex have a very
different kinematic structure than stars with higher [Fe/H].
Conclusions. Comparing with recent models for the Galactic boxy-peanut
bulge, the abundance gradients and distribution, and the relation
between [Fe/H] and kinematics suggests that the stars comprising each
maximum have separate disk origins with the '[Fe/H]-poor [Mg/Fe]-rich'
stars originating from a thicker disk than the '[Fe/H]-rich
[Mg/Fe]-poor' stars.
Description:
The A2A survey is obtained by cross-matching the medium resolution
spectroscopic survey ARGOS with the high-resolution spectroscopic
survey APOGEE DR16. The stellar parameters of the ARGOS stars are
recalibrated to the APOGEE stellar parameter scale using the
data-driven method The Cannon and a set of training stars observed by
both surveys. The table provides revised values of effective
temperature, logg, [Fe/H] and [Mg/Fe] with estimated errors,
heliocentric radial velocities, as well as photometric information and
probability weights for these stars being part of the red clump.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 158 21325 Final catalog of all A2A stars with position,
magnitude and radial velocity data,
spectroscopic parameters, and red clump weights
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See also:
V/154 : SDSS Release 16 (DR16) (Ahumada+, 2020)
J/ApJ/808/16 : The Cannon: a new approach to determine abundances (Ness+, 2015)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- imbin I-mag bin of star (1)
9- 15 F7.3 deg RAdeg Right ascension (J2000)
18- 24 F7.3 deg DEdeg Declination (J2000)
27- 33 F7.3 deg GLON [] Galactic longitude
36- 42 F7.3 deg GLAT Galactic latitude
45- 49 F5.3 mag Ak Extinction
52- 57 F6.3 mag Kmag K-magnitude
60- 64 F5.3 mag (J-K)0 Extinction corrected color (J-K)0
67- 71 F5.3 [cm/s2] logg Log10 of surface gravity
78- 82 F5.3 [cm/s2] e_logg Error in logg
85- 92 F8.3 K Teff Effective temperature
96-102 F7.3 K e_Teff Error in Teff
105-110 F6.3 [-] [Fe/H] Iron-to-Hydrogen ratio
115-119 F5.3 [-] e_[Fe/H] Error in [Fe/H]
122-127 F6.3 --- [Mg/Fe] Magnesium-to-Iron ratio
133-137 F5.3 --- e_[Mg/Fe] Error in [Mg/Fe]
140-147 F8.3 km/s VHelio Line-of-sight velocity
154-158 F5.3 --- RCWeight [0/1] Weight of star for being red clump (2)
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Note (1): ARGOS survey stars were selected in I-mag bins 13-14, 14-15, 15-16.
'imbin' specifies which bin a given star falls into,
'0' for I-mag in 13-14 etc.
Note (2): For details, see eq. (9) of the paper.
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Acknowledgements:
A. Pandey, Max-Planck-Inst. Ex. Physics, Garching, Germany,
Ortwin Gerhard, gerhard(at)mpe.mpg.de
References:
Ness et al., ARGOS catalog, 2013MNRAS.430..836N 2013MNRAS.430..836N
Ahumada et al., APOGEE DR16, 2020ApJS..249....3A 2020ApJS..249....3A, Cat. V/154
Ness et al., The Cannon, 2015ApJ...808...16N 2015ApJ...808...16N, Cat. J/ApJ/808/16
(End) Patricia Vannier [CDS] 06-Oct-2023