J/MNRAS/465/501 APOGEE N-rich stars in inner Galaxy (Schiavon+, 2017)
Chemical tagging with APOGEE:
discovery of a large population of N-rich stars in the inner Galaxy.
Schiavon R.P., Zamora O., Carrera R., Lucatello S., Robin A.C., Ness M.,
Martell S.L., Smith V.V., Garcia-Hernandez D.A., Manchado A., Schonrich R.,
Bastian N., Chiappini C., Shetrone M., Mackereth J.T., Williams R.A.,
Meszaros S., Allende Prieto C., Anders F., Bizyaev D., Beers T.C.,
Chojnowski S.D., Cunha K., Epstein C., Frinchaboy P.M., Garcia Perez A.E.,
Hearty F.R., Holtzman J.A., Johnson J.A., Kinemuchi K., Majewski S.R.,
Muna D., Nidever D.L., Nguyen D.C., O'Connell R.W., Oravetz D., Pan K.,
Pinsonneault M., Schneider D.P., Schultheis M., Simmons A., Skrutskie M.F.,
Sobeck J., Wilson J.C., Zasowski G.
<Mon. Not. R. Astron. Soc., 465, 501-524 (2017)>
=2017MNRAS.465..501S 2017MNRAS.465..501S (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, peculiar ; Abundances
Keywords: stars: abundances - stars: chemically peculiar - Galaxy: abundances -
Galaxy: bulge - globular clusters: general - Galaxy: halo
Abstract:
Formation of globular clusters (GCs), the Galactic bulge, or galaxy
bulges in general is an important unsolved problem in Galactic
astronomy. Homogeneous infrared observations of large samples of stars
belonging to GCs and the Galactic bulge field are one of the best ways
to study these problems. We report the discovery by APOGEE (Apache
Point Observatory Galactic Evolution Experiment) of a population of
field stars in the inner Galaxy with abundances of N, C, and Al that
are typically found in GC stars. The newly discovered stars have high
[N/Fe], which is correlated with [Al/Fe] and anticorrelated with
[C/Fe]. They are homogeneously distributed across, and kinematically
indistinguishable from, other field stars within the same volume.
Their metallicity distribution is seemingly unimodal, peaking at
[Fe/H]~-1, thus being in disagreement with that of the Galactic
GC system. Our results can be understood in terms of different
scenarios. N-rich stars could be former members of dissolved GCs, in
which case the mass in destroyed GCs exceeds that of the surviving GC
system by a factor of ∼8. In that scenario, the total mass contained
in so-called 'first-generation' stars cannot be larger than that
in 'second-generation' stars by more than a factor of ∼9 and was
certainly smaller. Conversely, our results may imply the absence of a
mandatory genetic link between 'second-generation' stars and GCs.
Last, but not least, N-rich stars could be the oldest stars in the
Galaxy, the by-products of chemical enrichment by the first stellar
generations formed in the heart of the Galaxy.
Description:
The results reported in this paper are based on elemental abundances
for a large sample of Galactic stars from Data Release 12 (DR12; Alam
et al., 2015ApJS..219...12A 2015ApJS..219...12A, Cat. V/147) of the Apache Point
Observatory Galactic Evolution Experiment (APOGEE; Majewski et al.,
2017AJ....154...94M 2017AJ....154...94M).
In this paper, we concern ourselves with a subset of the APOGEE
sample, namely stars located in the Galactic bulge. Moreover, because
we are interested in searching for stars with chemical signatures
typical of GC members, we focus on the abundances of Fe, C, N, and Al.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 106 58 N-rich stars identified in the inner Galaxy
bulge.dat 424 5148 Galactic bulge sample used in the paper
m3.dat 296 32 M3 sample used in the paper
m5.dat 296 25 M5 sample used in the paper
m71.dat 296 10 M71 sample used in the paper
m107.dat 296 8 M107 sample used in the paper
n6760.dat 296 9 NGC 6760 sample used in the paper
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/AJ/146/133 : Stellar parameters from SDSS-III APOGEE DR10 (Meszaros+, 2013)
J/AJ/146/156 : APOGEE M-dwarf survey I First year velocities (Deshpande+, 2013)
J/ApJ/819/2 : APOGEE kinematics. I. Galactic bulge overview (Ness+, 2016)
J/ApJ/852/49 : Properties of metal-poor stars in APOGEE DR13 (Hayes+, 2018)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name APOGEE designation (2MHHMMSSss+DDMMSSs)
20- 29 F10.6 deg RAdeg Right ascension (J2000)
31- 40 F10.6 deg DEdeg Declination (J2000)
42- 44 I3 --- S/N Signal-to-noise ratio
46- 49 I4 K Teff Effective temperature
51- 54 F4.1 [cm/s2] logg Surface gravity
56- 60 F5.2 [-] [Fe/H] Metallicity
62- 65 F4.2 [-] e_[Fe/H] rms uncertainty on [Fe/H]
67- 71 F5.2 [-] [Al/Fe] Abundance [Al/Fe]
73- 76 F4.2 [-] e_[Al/Fe] rms uncertainty on [Al/Fe]
78- 82 F5.2 [-] [C/Fe] Abundance [Cl/Fe]
84- 87 F4.2 [-] e_[C/Fe] rms uncertainty on [C/Fe]
89- 92 F4.2 [-] [N/Fe] Abundance [N/Fe]
94- 97 F4.2 [-] e_[N/Fe] rms uncertainty on [N/Fe]
99-102 F4.1 kpc Dist Distance
104-106 F3.1 kpc e_Dist rms uncertainty on Dist
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Byte-by-byte Description of file: bulge.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name APOGEE designation (2MHHMMSSss+DDMMSSs)
20- 25 F6.3 mag Jmag J magnitude
27- 31 F5.3 mag e_Jmag rms uncertainty on Jmag
33- 38 F6.3 mag Hmag H magnitude
40- 44 F5.3 mag e_Hmag rms uncertainty on Hmag
46- 51 F6.3 mag Kmag K magnitude
53- 57 F5.3 mag e_Kmag rms uncertainty on Kmag
59- 68 F10.6 deg RAdeg Right ascension (J2000)
70- 79 F10.6 deg DEdeg Declination (J2000)
81- 90 F10.6 deg GLON Galactic longitude
92-101 F10.6 deg GLAT Galactic latitude
103 I1 --- N Number of visits
105-112 F8.4 --- S/N Signal-to-noise ratio
114-124 F11.6 km/s HVavg Average heliocentric velocity
126-134 F9.6 km/s sigma Scatter of individual visit HVs
around average
136-143 F8.6 km/s e_HV Velocity error
145-152 F8.6 km/s e_HVmed Median of individual visit HVs
around average
154-160 F7.2 K Teff Effective temperature
162-168 F7.4 K e_Teff rms uncertainty on Teff
170-178 F9.6 [cm/s2] logg Surface gravity
180-187 F8.6 [cm/s2] e_logg rms uncertainty on logg
189-200 F12.6 [-] [Al/H] ?=-9999 Abundance [Al/H]
202-210 F9.6 [-] [C/H] Abundance [C/H]
212-220 F9.6 [-] [Fe/H] Abundance [Fe/H]
222-230 F9.6 [-] [N/H] Abundance [N/H]
232-243 F12.6 [-] e_[Al/H] ?=-9999 Abundance [Al/H]
245-252 F8.6 [-] e_[C/H] Abundance [C/H]
254-265 F12.6 [-] e_[Fe/H] Abundance [Fe/H]
267-274 F8.6 [-] e_[N/H] Abundance [N/H]
276-287 F12.6 mag IRAC1 ?=-9999 IRAC1 (3.6um) magnitude
289-300 F12.6 mag e_IRAC1 ?=-9999 rms uncertainty on IRAC1
302-313 F12.6 mag IRAC2 ?=-9999 IRAC2 (4.5um) magnitude
315-326 F12.6 mag e_IRAC2 ?=-9999 rms uncertainty on IRAC2
328-339 F12.6 mag IRAC3 ?=-9999 IRAC3 (5.8um) magnitude
341-352 F12.6 mag e_IRAC3 ?=-9999 rms uncertainty on IRAC3
354-365 F12.6 mag IRAC4 ?=-9999 IRAC4 (8.0um) magnitude
367-378 F12.6 mag e_IRAC4 ?=-9999 rms uncertainty on IRAC4
380-388 F9.6 mag EKs Ks-band extinction from APOGEE Targeting
(AK_TARG)
390-397 F8.5 --- Diso1 APOGEE distance 1
399-406 F8.5 --- Diso2 APOGEE distance 2
408-415 F8.5 --- Diso3 APOGEE distance 3
417-424 F8.6 --- e_Diso Error in distance
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Byte-by-byte Description of file: m107.dat m3.dat m5.dat m71.dat n6760.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name APOGEE designation (2MHHMMSSss+DDMMSSs)
20- 28 F9.3 mag Jmag ?=-9999.99 J magnitude
30- 38 F9.3 mag e_Jmag ?=-9999.99 rms uncertainty on Jmag
40- 45 F6.3 mag Hmag ?=-9999.99 H magnitude
47- 55 F9.3 mag e_Hmag ?=-9999.99 rms uncertainty on Hmag
57- 62 F6.3 mag Kmag ?=-9999.99 K magnitude
64- 68 F5.3 mag e_Kmag ?=-9999.99 rms uncertainty on Kmag
70- 79 F10.6 deg RAdeg Right ascension (J2000)
81- 90 F10.6 deg DEdeg Declination (J2000)
92 I1 --- N [1/5] Number of visits
94-100 F7.3 --- S/N Signal-to-noise ratio
102-112 F11.6 km/s HVavg Average heliocentric velocity
114-121 F8.6 km/s sigma Scatter of individual visit HVs
around average
123-130 F8.6 km/s e_HV Heliocentric velocity error
132-139 F8.4 km/s e_HVmed Median of individual visit HVs
around average
141-148 F8.2 K Teff ?=-9999 Effective temperature
150-161 F12.6 [cm/s2] logg ?=-9999 Surface gravity
163-169 F7.4 K e_Teff ?=-1 rms uncertainty on Teff
171-179 F9.6 [cm/s2] e_logg ?=-1 rms uncertainty on logg
181-192 F12.6 [-] [Al/H] ?=-9999 Abundance [Al/H]
194-205 F12.6 [-] [C/H] ?=-9999 Abundance [C/H]
207-218 F12.6 [-] [Fe/H] ?=-9999 Abundance [Fe/H]
220-231 F12.6 [-] [N/H] ?=-9999 Abundance [N/H]
233-244 F12.6 [-] e_[Al/H] ?=-9999 Abundance [Al/H]
246-257 F12.6 [-] e_[C/H] ?=-9999 Abundance [C/H]
259-270 F12.6 [-] e_[Fe/H] ?=-9999 Abundance [Fe/H]
272-283 F12.6 [-] e_[N/H] ?=-9999 Abundance [N/H]
285-296 F12.6 mag EKs ?=-9999.99 Ks-band extinction from
APOGEE Targeting (AK_TARG)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-Jun-2018