J/MNRAS/460/884 EMBLA survey. Galactic bulge metal-poor stars (Howes+, 2016)
The EMBLA survey - metal-poor stars in the Galactic bulge.
Howes L.M., Asplund M., Keller S.C., Casey A.R., Yong D., Lind K.,
Frebel A., Hays A., Alves-Brito A., Bessell M.S., Casagrande L.,
Marino A.F., Nataf D.M., Owen C.I., Da Costa G.S., Schmidt B.P.,
Tisserand P.
<Mon. Not. R. Astron. Soc., 460, 884-901 (2016)>
=2016MNRAS.460..884H 2016MNRAS.460..884H (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, population II ; Abundances
Keywords: stars: abundances - stars: Population II - Galaxy: bulge -
Galaxy: evolution
Abstract:
Cosmological models predict the oldest stars in the Galaxy should be
found closest to the centre of the potential well, in the bulge. The
Extremely Metal-poor BuLge stars with AAOmega survey (EMBLA)
successfully searched for these old, metal-poor stars by making use of
the distinctive SkyMapper photometric filters to discover candidate
metal-poor stars in the bulge. Their metal-poor nature was then
confirmed using the AAOmega spectrograph on the Anglo-Australian
Telescope. Here we present an abundance analysis of 10 bulge stars
with -2.8<[Fe/H]←1.7 from MIKE/Magellan observations, in total
determining the abundances of 22 elements. Combining these results
with our previous high-resolution data taken as part of the Gaia-ESO
Survey, we have started to put together a picture of the chemical and
kinematic nature of the most metal-poor stars in the bulge. The
currently available kinematic data are consistent with the stars
belonging to the bulge, although more accurate measurements are needed
to constrain the stars' orbits. The chemistry of these bulge stars
deviates from that found in halo stars of the same metallicity. Two
notable differences are the absence of carbon-enhanced metal-poor
bulge stars, and the α element abundances exhibit a large
intrinsic scatter and include stars which are underabundant in these
typically enhanced elements.
Description:
Ten stars were observed using the MIKE high-resolution spectrograph
on Magellan's 6.5m Clay telescope. The observations took place between
April and June of 2012, and all make use of the full wavelength
coverage offered by MIKE, with the spectra covering (as a minimum)
370-890nm. All except one star (SMSS J182637.10-342924.2) were
configured with a 1.0 arcsec slit, resulting in resolving powers of
22000 in the blue and 28000 in the red, and were binned by two in both
the spatial and spectral directions. SMSS J182637.10-342924.2 was
instead observed in April as part of a different set of observations,
where a slit with width of 0.35-arcsec and no spatial or spectral
binning, was used. This provided resolving powers of 83000 and 65000,
in the blue and red, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 172 14 Stellar parameters for the 10 bulge stars and
the four stars originally published in
Howes et al. (2014MNRAS.445.4241H 2014MNRAS.445.4241H)
(tables 1, 4, 5 and 6 of the paper)
table7.dat 298 14 Chemical abundances for all 14 stars
table2.dat 38 232 Atomic data
table3.dat 86 203 *The measured equivalent widths of the 10 stars
for each spectral line
refs.dat 133 45 References
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Note on table3.dat: lines from Table 2 that are missing here were not measured
in any of these stars.
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1 A1 --- Flag [BH] B for bulge stars,
H for Howes et al. (2014MNRAS.445.4241H 2014MNRAS.445.4241H)
stars
3- 21 A19 --- SMSS SMSS star designation (JHHMMSS.ss+DDMMSS.s)
23- 28 F6.2 deg GLON [] Galactic longitude
30- 35 F6.2 deg GLAT Galactic latitude
37- 46 A10 "date" Obs.Date Observation date (only for bulge stars)
48- 52 I5 s Texp ? Exposure time (only for bulge stars)
54- 56 I3 nm lambda1 ? Wavelength range (only for bulge stars)
57 A1 --- --- [-] (only for bulge stars)
58- 60 I3 nm lambda2 ? Wavelength range (only for bulge stars)
62- 65 F4.2 arcsec Slit ? Slit width (only for bulge stars)
67- 68 I2 pix-1 S/N450 ? Signal-to-noise per pixel at 450nm
(only for bulge stars)
69- 70 I2 pix-1 S/Ntot ? Median S/N per pixel calculated across
total wavelength range (only for H stars)
72- 78 F7.2 km/s VGC Galactocentric velocity (1)
80- 83 F4.1 kpc Dist Heliocentric distance (this paper)
85- 87 F3.1 kpc e_Dist rms uncertainty on Dist (this paper)
89- 92 I4 K Teff Effective temperature (this paper)
94- 96 I3 K e_Teff rms uncertainty on Teff (this paper)
98-101 F4.2 [cm/s2] logg Surface gravity (this paper)
103-106 F4.2 [cm/s2] e_logg rms uncertainty on logg (this paper)
108-112 F5.2 [-] [Fe/H] Metallicity (this paper)
114-117 F4.2 [-] e_[Fe/H] rms uncertainty on [Fe/H] (this paper)
119-121 F3.1 km/s vt Microturbulent velocity (this paper)
123-125 F3.1 km/s e_vt rms uncertainty on vt (this paper)
127-130 F4.1 kpc DistG ? Heliocentric distance from Gaia-ESO
(only for H stars)
132-134 F3.1 kpc e_DistG ? rms uncertainty on Dist from Gaia-ESO
(only for H stars)
136-139 I4 K TeffG ? Effective temperature from Gaia-ESO
(only for H stars)
141-143 I3 K e_TeffG ? rms uncertainty on Teff from Gaia-ESO
(only for H stars)
145-148 F4.2 [cm/s2] loggG ? Surface gravity from Gaia-ESO
(only for H stars)
150-153 F4.2 [cm/s2] e_loggG ? rms uncertainty on logg from Gaia-ESO
(only for H stars)
155-159 F5.2 [-] [Fe/H]G ? Metallicity from Gaia-ESO
(only for H stars)
161-164 F4.2 [-] e_[Fe/H]G ? rms uncertainty on [Fe/H] from Gaia-ESO
(only for H stars)
166-168 F3.1 km/s vtG ? Microturbulent velocity from Gaia-ESO
(only for H stars)
170-172 F3.1 km/s e_vtG ? rms uncertainty on vt from Gaia-ESO
(only for H stars)
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Note (1): For bulge stars, calculated using equation (4)
VGC = Vhelio + 220sin(l)cos(b) + 16.5(sin(b)sin(25) + cos(b)cos(25)cos[l-53])
where Vhelio is the star's heliocentric velocity, and l and b are the
Galactic coordinates in degrees.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SMSS SMSS star designation (JHHMMSS.ss+DDMMSS.s)
21- 26 F6.2 --- [C/Fe] ?=-99.9 Abundance [C/Fe]
28- 33 F6.2 --- e_[C/Fe] ?=-99.9 rms uncertainty on [C/Fe]
35- 40 F6.2 --- [O/Fe] ?=-99.9 Abundance [O/Fe]
42- 47 F6.2 --- e_[O/Fe] ?=-99.9 rms uncertainty on [O/Fe]
49- 54 F6.2 --- [Na/Fe] ?=-99.9 Abundance [Na/Fe]
56- 61 F6.2 --- e_[Na/Fe] ?=-99.9 rms uncertainty on [Na/Fe]
63- 67 F5.2 --- [Mg/Fe] Abundance [Mg/Fe]
69- 72 F4.2 --- e_[Mg/Fe] rms uncertainty on [Mg/Fe]
74- 79 F6.2 --- [Al/Fe] ?=-99.9 Abundance [Al/Fe]
81- 86 F6.2 --- e_[Al/Fe] ?=-99.9 rms uncertainty on [Al/Fe]
88- 93 F6.2 --- [Si/Fe] ?=-99.9 Abundance [Si/Fe]
95-100 F6.2 --- e_[Si/Fe] ?=-99.9 rms uncertainty on [Si/Fe]
102-107 F6.2 --- [K/Fe] ?=-99.9 Abundance [K/Fe]
109-114 F6.2 --- e_[K/Fe] ?=-99.9 rms uncertainty on [K/Fe]
116-120 F5.2 --- [Ca/Fe] Abundance [Ca/Fe]
122-125 F4.2 --- e_[Ca/Fe] rms uncertainty on [Ca/Fe]
127-132 F6.2 --- [Sc/Fe] ?=-99.9 Abundance [Sc/Fe]
134-139 F6.2 --- e_[Sc/Fe] ?=-99.9 rms uncertainty on [Sc/Fe]
141-145 F5.2 --- [Ti/Fe] Abundance [Ti/Fe]
147-150 F4.2 --- e_[Ti/Fe] rms uncertainty on [Ti/Fe]
152-157 F6.2 --- [Cr/Fe] ?=-99.9 Abundance [Cr/Fe]
159-164 F6.2 --- e_[Cr/Fe] ?=-99.9 rms uncertainty on [Cr/Fe]
166-171 F6.2 --- [Mn/Fe] ?=-99.9 Abundance [Mn/Fe]
173-178 F6.2 --- e_[Mn/Fe] ?=-99.9 rms uncertainty on [Mn/Fe]
180-185 F6.2 --- [Co/Fe] ?=-99.9 Abundance [Co/Fe]
187-192 F6.2 --- e_[Co/Fe] ?=-99.9 rms uncertainty on [Co/Fe]
194-198 F5.2 --- [Ni/Fe] Abundance [Ni/Fe]
200-203 F4.2 --- e_[Ni/Fe] rms uncertainty on [Ni/Fe]
205-210 F6.2 --- [Zn/Fe] ?=-99.9 Abundance [Zn/Fe]
212-217 F6.2 --- e_[Zn/Fe] ?=-99.9 rms uncertainty on [Zn/Fe]
219-224 F6.2 --- [Sr/Fe] ?=-99.9 Abundance [Sr/Fe]
226-231 F6.2 --- e_[Sr/Fe] ?=-99.9 rms uncertainty on [Sr/Fe]
233-238 F6.2 --- [Y/Fe] ?=-99.9 Abundance [Y/Fe]
240-245 F6.2 --- e_[Y/Fe] ?=-99.9 rms uncertainty on [Y/Fe]
247-252 F6.2 --- [Zr/Fe] ?=-99.9 Abundance [Zr/Fe]
254-259 F6.2 --- e_[Zr/Fe] ?=-99.9 rms uncertainty on [Zr/Fe]
261-265 F5.2 --- [Ba/Fe] Abundance [Ba/Fe]
267-270 F4.2 --- e_[Ba/Fe] rms uncertainty on [Ba/Fe]
272-277 F6.2 --- [La/Fe] ?=-99.9 Abundance [La/Fe]
279-284 F6.2 --- e_[La/Fe] ?=-99.9 rms uncertainty on [La/Fe]
286-291 F6.2 --- [Eu/Fe] ?=-99.9 Abundance [Eu/Fe]
293-298 F6.2 --- e_[Eu/Fe] ?=-99.9 rms uncertainty on [Eu/Fe]
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Ion
7- 14 F8.4 nm lambda Wavelength
16- 20 F5.3 eV EP Excitation potential
23- 29 F7.3 [-] loggf Oscillator strength
31- 38 A8 --- Ref Reference, in refs.dat file
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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- 5 A5 --- Ion Ion
7- 14 F8.4 nm lambda Wavelength
16- 21 F6.2 0.1pm EW1 ? J182637.10-342924.2 equivalent width
23- 28 F6.2 0.1pm EW2 ? J182600.09-332531.0 equivalent width
30- 35 F6.2 0.1pm EW3 ? J182601.24-332358.3 equivalent width
37- 43 F7.3 0.1pm EW4 ? J182753.81-334607.7 equivalent width
45- 50 F6.2 0.1pm EW5 ? J183000.36-333919.3 equivalent width
52- 57 F6.2 0.1pm EW6 ? J182922.48-335559.4 equivalent width
59- 64 F6.2 0.1pm EW7 ? J182930.47-335958.3 equivalent width
66- 71 F6.2 0.1pm EW8 ? J183225.29-334938.4 equivalent width
73- 79 F7.3 0.1pm EW9 ? J183128.71-341018.4 equivalent width
81- 86 F6.2 0.1pm EW10 ? J182948.48-341053.9 equivalent width
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 63 A40 --- Aut Author's name
65-133 A69 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Oct-2017