J/ApJ/763/61 Abundances of 7 red giant members of BootesI (Gilmore+, 2013)
Elemental abundances and their implications for the chemical enrichment of the
Bootes I ultrafaint galaxy.
Gilmore G., Norris J.E., Monaco L., Yong D., Wyse R.F.G., Geisler D.
<Astrophys. J., 763, 61 (2013)>
=2013ApJ...763...61G 2013ApJ...763...61G
ADC_Keywords: Abundances ; Stars, giant ; Radial velocities ; Equivalent widths
Keywords: galaxies: abundances; galaxies: dwarf; galaxies: individual: Bootes I;
Galaxy: abundances; stars: abundances
Abstract:
We present a double-blind analysis of high-dispersion spectra of seven
red giant members of the Bootes I ultrafaint dwarf spheroidal galaxy,
complemented with re-analysis of a similar spectrum of an
eighth-member star. The stars cover [Fe/H] from -3.7 to -1.9 and
include a CEMP-no star with [Fe/H]=-3.33. We conclude from our
chemical abundance data that Bootes I has evolved as a self-enriching
star-forming system, from essentially primordial initial abundances.
This allows us uniquely to investigate the place of CEMP-no stars in a
chemically evolving system, in addition to limiting the timescale of
star formation. The elemental abundances are formally consistent with
a halo-like distribution, with enhanced mean [α/Fe] and small
scatter about the mean. This is in accord with the high-mass stellar
initial mass function in this low-stellar-density, low-metallicity
system being indistinguishable from the present-day solar neighborhood
value. There is a non-significant hint of a decline in [α/Fe]
with [Fe/H]; together with the low scatter, this requires low star
formation rates, allowing time for supernova ejecta to be mixed over
the large spatial scales of interest. One star has very high [Ti/Fe],
but we do not confirm a previously published high value of [Mg/Fe] for
another star. We discuss the existence of CEMP-no stars, and the
absence of any stars with lower CEMP-no enhancements at higher [Fe/H],
a situation that is consistent with knowledge of CEMP-no stars in the
Galactic field. We show that this observation requires there be two
enrichment paths at very low metallicities: CEMP-no and
"carbon-normal."
Description:
High-resolution, moderate-S/N, spectra were obtained of seven BootesI
red giants as part of a larger program to investigate the kinematics
and chemical abundances of the Bootes I system. During 2009
February-March, data were obtained with the FLAMES spectrograph of the
8.2m Kueyen (VLT/UT2) telescope at Cerro Paranal, Chile. The spectra
cover the wavelength ranges 4800-5750Å and 5840-6800Å, and have
resolving power R=47000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 64 7 The seven Bootes I red giant program stars
table2.dat 41 7 Radial velocities for program stars
table3.dat 63 7 Atmospheric parameters for program stars
table4.dat 107 115 *NY atomic data, equivalent widths, and absolute
abundances
table5.dat 108 226 *GM atomic data, equivalent widths, and absolute
abundances
table8.dat 61 8 Adopted α-element abundances
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Note on table4.dat and table5.dat: Throughout the paper, "NY" stand for
Norris J.E. & Yong D. and "GM" are for Geisler D. & Monaco L. for the
double-blind analysis (see section 1.1).
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/A+A/562/A146 : Chemical abundances of 8 metal-poor stars (Ishigaki+, 2014)
J/ApJ/736/146 : Radial velocities of stars in Bootes I (Koposov+, 2011)
J/ApJ/723/1632 : Abundance spreads in Bootes I and Segue 1 (Norris+, 2010)
J/ApJ/711/350 : Metal-poor giant Boo-1137 abundances (Norris+, 2010)
J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)
J/MNRAS/380/281 : Faint galactic satellites spectrosc. survey (Martin+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Identification number
(<[NWG2010] BooI NNN> in Simbad)
6- 7 I2 --- M07 ? Identification number from Martin+, 2007,
Cat. J/MNRAS/380/281
9- 10 I2 --- L11 ? Identification number from
Lai+ (2011ApJ...738...51L 2011ApJ...738...51L)
12- 13 I2 h RAh Hour of right ascension (J2000)
15- 16 I2 min RAm Minute of right ascension (J2000)
18- 22 F5.2 s RAs Second of right ascension (J2000)
24 A1 --- DE- Sign of declination (J2000)
25- 26 I2 deg DEd Degree of declination (J2000)
28- 29 I2 arcmin DEm Arcminute of declination (J2000)
31- 34 F4.1 arcsec DEs Arcsecond of declination (J2000)
36- 41 F6.3 mag g0mag [17.4/18.4] SDSS-DR7 g0-band magnitude (1)
43- 47 F5.3 mag (g-r)0 [0.6/0.9] (g-r)0 color index (1)
49- 53 F5.2 [Sun] [Fe/H]a [-3/-1.4]? Abundance [Fe/H] using CaIIK line (2)
55- 58 F4.1 [Sun] [Fe/H]b [-3/-1.6]? Abundance [Fe/H] using CaII IR
triplet (3)
60- 64 F5.2 [Sun] [Fe/H]c [-4/-1.6]? Abundance [Fe/H] (4)
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Note (1): SDSS Data Release 7 (Abazajian et al. 2009, Cat. II/294) ugriz
photometry g0 and (g-r)0 (where a reddening of E(B-V)=0.02
(Belokurov et al. 2006ApJ...647L.111B 2006ApJ...647L.111B) has been adopted).
Note (2): [Fe/H] determined by Norris et al. (2008ApJ...689L.113N 2008ApJ...689L.113N) using the
CaII K line.
Note (3): [Fe/H] determined by Martin et al. (2007, Cat. J/MNRAS/380/281) using
the CaII infrared triplet.
Note (4): [Fe/H] determined by Lai et al. (2011ApJ...738...51L 2011ApJ...738...51L) using
intermediate-resolution blue data.
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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- 4 I4 --- Star Star number
6- 11 F6.2 km/s RVny Radial velocity determined by Norris & Yong
13- 16 F4.2 km/s e_RVny Internal standard error in RVny
18- 19 I2 --- o_RVny Number of individual spectra that were measured
21- 26 F6.2 km/s RVgm Radial velocity determined by Geisler & Monaco
28- 31 F4.2 km/s e_RVgm Internal standard error in RVgm
33- 34 I2 --- o_RVgm Number of individual spectra that were measured
36- 41 F6.2 km/s HRV [92.5/107] Mean radial velocity
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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- 4 I4 --- Star Star number
6- 9 I4 K Teff1 [4570/4790] Effective temperature (1)
11- 13 F3.1 [cm/s2] logg1 [0.8/1.6] Surface gravity (1)
15- 19 F5.2 [Sun] [Fe/H]1 [-3.3/-1.9] Abundance [Fe/H] (1)(4)
21- 23 F3.1 km/s Vt1 [2.4/3.3] Microturbulent velocity (1)
25- 28 I4 K Teff2 [4550/4800] Effective temperature (2)
30- 32 F3.1 [cm/s2] logg2 [0.9/1.4] Surface gravity (2)
34- 38 F5.2 [Sun] [Fe/H]2 [-3.44/-1.8] Abundance [Fe/H] (2)(4)
40- 42 F3.1 km/s Vt2 [1.8/2.9] Microturbulent velocity (2)
44 A1 --- l_Teff3 Limit flag on Teff3
46- 49 I4 K Teff3 [4600/4600]? Effective temperature (3)
51- 53 F3.1 [cm/s2] logg3 [0.5/1]? Surface gravity (3)
55- 59 F5.2 [Sun] [Fe/H]3 [-2.95/-2.03]? Abundance [Fe/H] (3)(4)
61- 63 F3.1 km/s Vt3 [2.1/2.1]? Microturbulent velocity (3)
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Note (1): Determined by Norris & Yong (NY).
Note (2): Determined by Geisler & Monaco (GM).
Note (3): Determined by Feltzing et al. (2009A&A...508L...1F 2009A&A...508L...1F)
Note (4): Assuming logε☉(Fe)=7.50, following Asplund et al.
(2009ARA&A..47..481A 2009ARA&A..47..481A).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Ion Species identifier
6- 12 F7.2 0.1nm lambda [4810/6644] Wavelength λ (Å)
14- 17 F4.2 eV chi Excitation potential
19- 23 F5.2 [-] log(gf) Log of the oscillator strength
25- 29 F5.1 10-13m EW33 ? Equivalent width in Boo 33 (mÅ)
31- 35 F5.2 [-] loge33 ? Log absolute abundance in Boo 33 (2)
37- 41 F5.1 10-13m EW41 ? Equivalent width in Boo 41 (mÅ)
43- 47 F5.2 [-] loge41 ? Log absolute abundance in Boo 41 (2)
49- 53 F5.1 10-13m EW94 ? Equivalent width in Boo 94 (mÅ)
55- 59 F5.2 [-] loge94 ? Log absolute abundance in Boo 94 (2)
61- 65 F5.1 10-13m EW117 ? Equivalent width in Boo 117 (mÅ)
67- 71 F5.2 [-] loge117 ? Log absolute abundance in Boo 117 (2)
73- 77 F5.1 10-13m EW119 ? Equivalent width in Boo 119 (mÅ)
79- 83 F5.2 [-] loge119 ? Log absolute abundance in Boo 119 (2)
85- 89 F5.1 10-13m EW127 ? Equivalent width in Boo 127 (mÅ)
91- 95 F5.2 [-] loge127 ? Log absolute abundance in Boo 127 (2)
97-101 F5.1 10-13m EW130 ? Equivalent width in Boo 130 (mÅ)
103-107 F5.2 [-] loge130 ? Log absolute abundance in Boo 130 (2)
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Note (2): where loge(X) = (log(NX/NH)+12.0)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Species identifier
7- 14 F8.3 0.1nm lambda [4810/6768] Wavelength λ (Å)
16- 20 F5.3 eV chi Excitation potential χ
22- 27 F6.3 [-] log(gf) Log of the oscillator strength
29- 33 F5.1 10-13m EW33 ? Equivalent width in Boo 33 (1)
35- 39 F5.2 [-] loge33 ? Log absolute abundance in Boo 33 (2)
41- 45 F5.1 10-13m EW41 ? Equivalent width in Boo 41 (1)
47- 50 F4.2 [-] loge41 ? Log absolute abundance in Boo 41 (2)
52- 56 F5.1 10-13m EW94 ? Equivalent width in Boo 94 (1)
58- 62 F5.2 [-] loge94 ? Log absolute abundance in Boo 94 (2)
64- 68 F5.1 10-13m EW117 ? Equivalent width in Boo 117 (1)
70- 74 F5.2 [-] loge117 ? Log absolute abundance in Boo 117 (2)
76- 80 F5.1 10-13m EW119 ? Equivalent width in Boo 119 (1)
82- 85 F4.2 [-] loge119 ? Log absolute abundance in Boo 119 (2)
87- 91 F5.1 10-13m EW127 ? Equivalent width in Boo 127 (1)
93- 97 F5.2 [-] loge127 ? Log absolute abundance in Boo 127 (2)
99-102 F4.1 10-13m EW130 ? Equivalent width in Boo 130 (1)
104-108 F5.2 [-] loge130 ? Log absolute abundance in Boo 130 (2)
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Note (1): In units of milli-Angstroms.
Note (2): where loge(X) = (log(NX/NH) + 12.0)
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [Boo-]
5- 8 I4 --- Star [33/1137] Star number
9 A1 --- f_Star [d] d: CEMP-no star (Carbon-Enhanced Metal-Poor
with no enhancement of heavy neutron-capture
elements over Solar ratios )
11- 14 F4.2 [Sun] [Mg/Fe] [0.1/1.1] Magnesium abundance
16- 19 F4.2 [Sun] e_[Mg/Fe] [0.1/0.3] [Mg/Fe] uncertainty (1)
21- 24 F4.2 [Sun] [Ca/Fe] [0.1/0.6] Calcium abundance
26- 29 F4.2 [Sun] e_[Ca/Fe] [0.05/0.2] [Ca/Fe] uncertainty (1)
31- 35 F5.2 [Sun] [Ti/Fe] [-0.02/0.8] Titanium abundance
37- 40 F4.2 [Sun] e_[Ti/Fe] [0.1/0.3] [Ti/Fe] uncertainty (1)
42- 45 F4.2 [Sun] [a/Fe] [0.1/0.8] α-elements abundance (2)
47- 50 F4.2 [Sun] e_[a/Fe] [0.09/0.2] [a/Fe] uncertainty (3)
52- 56 F5.2 [Sun] [Fe/H] [-3.7/-1.8] Iron abundance
58- 61 F4.2 [Sun] e_[Fe/H] [0.1/0.2] [Fe/H] uncertainty (1)
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Note (1): Arithmetic mean of Norris & Yong (NY) and Geisler & Monaco (GM)
errors.
Note (2): [α/Fe]=([Mg/Fe]+[Ca/Fe]+[Ti/Fe])/3.
Note (3): Quadrature mean of NY and GM errors, except for Boo-119 and Boo-1137
for which the values are based on the analysis of GM and the present
reanalysis of the data of Norris et al. (2010, Cat. J/ApJ/711/350),
respectively.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Oct-2014