J/ApJ/804/109 Equivalent widths of RGB stars in NGC 5053 (Boberg+, 2015)
Chemical abundances in NGC 5053: a very metal-poor and dynamically complex
globular cluster.
Boberg O.M., Friel E.D., Vesperini E.
<Astrophys. J., 804, 109 (2015)>
=2015ApJ...804..109B 2015ApJ...804..109B
ADC_Keywords: Equivalent widths ; Clusters, globular ; Radial velocities ;
Magnitudes, absolute ; Stars, giant
Keywords: Galaxy: abundances; globular clusters: individual: NGC 5053
Abstract:
NGC 5053 provides a rich environment to test our understanding of the
complex evolution of globular clusters (GCs). Recent studies have
found that this cluster has interesting morphological features beyond
the typical spherical distribution of GCs, suggesting that external
tidal effects have played an important role in its evolution and
current properties. Additionally, simulations have shown that NGC 5053
could be a likely candidate to belong to the Sagittarius dwarf galaxy
(Sgr dSph) stream. Using the Wisconsin-Indiana-Yale-NOAO-Hydra
multi-object spectrograph, we have collected high quality
(signal-to-noise ratio ∼75-90), medium-resolution spectra for red
giant branch stars in NGC 5053. Using these spectra we have measured
the Fe, Ca, Ti, Ni, Ba, Na, and O abundances in the cluster. We
measure an average cluster [Fe/H] abundance of -2.45 with a standard
deviation of 0.04 dex, making NGC 5053 one of the most metal-poor GCs
in the Milky Way (MW). The [Ca/Fe], [Ti/Fe], and [Ba/Fe] we measure
are consistent with the abundances of MW halo stars at a similar
metallicity, with alpha-enhanced ratios and slightly depleted [Ba/Fe].
The Na and O abundances show the Na-O anti-correlation found in most
GCs. From our abundance analysis it appears that NGC 5053 is at least
chemically similar to other GCs found in the MW. This does not,
however, rule out NGC 5053 being associated with the Sgr dSph stream.
Description:
The spectroscopic data for this study were collected using the
Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope with the Hydra
multi-object spectrograph on 2014 January 18 and 2014 February 14
(wavelength range: ∼6063-6380Å).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 64 18 Observational data
table4.dat 113 31 Equivalent widths
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/579/A104 : Abundances in NGC 5053 and NGC 5634 (Sbordone+, 2015)
J/AJ/149/53 : RVs of 12 Milky Way globular clusters (Kimmig+, 2015)
J/AJ/142/126 : CN & CH in SDSS Galactic globular clusters (Smolinski+, 2011)
J/MNRAS/402/226 : NGC 5053 variables VrI light curves (Arellano Ferro+, 2010)
J/ApJ/712/L21 : Calcium abundances in 17 globular clusters (Carretta+, 2010)
J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)
J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)
J/A+A/465/815 : Abundances of Sgr dSph stars (Sbordone+, 2007)
J/AJ/132/85 : Equivalent width of 33 metal-poor RHB (Preston+, 2006)
J/ApJS/161/304 : Star clusters in the MW and satellites (McLaughlin+, 2005)
J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)
J/A+A/350/955 : Atmospheric param. in metal-poor stars. II (Gratton+, 1999)
J/AJ/112/1489 : Spectroscopic survey for binaries in NGC 5053 (Yan+ 1996)
J/AJ/109/618 : RR Lyrae Stars in NGC 5053 (Nemec+ 1995)
J/AJ/109/269 : Photometry of NGC 5053 (Sarajedini+ 1995)
J/AJ/109/218 : Catalogue of globular cluster profiles (Trager+ 1995)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [2/23] Source identifier (1)
4- 5 I2 h RAh [13] Hour of Right Ascension (J2000)
7- 8 I2 min RAm [16] Minute of Right Ascension (J2000)
10- 14 F5.2 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- [+] Sign of the Declination (J2000)
17- 18 I2 deg DEd [17] Degree of Declination (J2000)
20- 21 I2 arcmin DEm [38/46] Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Arcsecond of Declination (J2000)
28- 32 F5.2 mag Vmag [14/15.4] Apparent V band magnitude (1)
34- 38 F5.2 mag VMag Absolute V band magnitude
40- 43 F4.2 mag (B-V)0 [0.7/1.1] Intrinsic (B-V) color index
45- 48 F4.2 mag (V-K)0 [1.8/2.8] Intrinsic (V-K) color index
50- 54 F5.1 km/s RVel [-27.1/44.2] Radial velocity
56- 58 F3.1 km/s e_RVel [0.6/2] Uncertainty in RVel
60- 62 I3 --- S/N [50/121] Signal-to-Noise ratio
64 A1 --- Mm [NY] Member?
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Note (1): ID number and Vmag from Sarajedini & Milone, 1995, J/AJ/109/269;
<Cl* NGC 5053 SM NNN> in Simbad.
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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- 3 A3 --- El Species name and ionization; I=neutral
(CaI, FeI, NiI or TiI)
5- 11 F7.2 0.1nm lambda [6102.7/6378.3] Wavelength
13- 18 F6.3 [-] log(gf) [-4.5/0] log Oscillator Strength
20- 23 F4.2 eV EP [0.8/4.2] Potential Energy
25- 29 F5.1 0.1pm EW2 [13/127]?=999.9 Equivalent width for Star 2 (1)
31- 35 F5.1 0.1pm EW3 [15/118]?=999.9 Equivalent width for Star 3 (1)
37- 41 F5.1 0.1pm EW4 [12/117]?=999.9 Equivalent width for Star 4 (1)
43- 47 F5.1 0.1pm EW6 [5/124]?=999.9 Equivalent width for Star 6 (1)
49- 53 F5.1 0.1pm EW9 [8/110]?=999.9 Equivalent width for Star 9 (1)
55- 59 F5.1 0.1pm EW11 [12/109]?=999.9 Equivalent width for Star 11 (1)
61- 65 F5.1 0.1pm EW12 [13/120]?=999.9 Equivalent width for Star 12 (1)
67- 71 F5.1 0.1pm EW14 [16/112]?=999.9 Equivalent width for Star 14 (1)
73- 77 F5.1 0.1pm EW15 [8/106]?=999.9 Equivalent width for Star 15 (1)
79- 83 F5.1 0.1pm EW16 [5/96]?=999.9 Equivalent width for Star 16 (1)
85- 89 F5.1 0.1pm EW17 [5/112]?=999.9 Equivalent width for Star 17 (1)
91- 95 F5.1 0.1pm EW19 [10/112]?=999.9 Equivalent width for Star 19 (1)
97-101 F5.1 0.1pm EW20 [3/102]?=999.9 Equivalent width for Star 20 (1)
103-107 F5.1 0.1pm EW21 [12/101]?=999.9 Equivalent width for Star 21 (1)
109-113 F5.1 0.1pm EW23 [4/93]?=999.9 Equivalent width for Star 23 (1)
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Note (1): In units of milli-Angstroms.
A 999.9 indicates that the line was not measured.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 26-Aug-2015