J/ApJ/824/5 Chemical abundances in NGC 5024 (M53) (Boberg+, 2016)
Chemical abundances in NGC 5024 (M53): a mostly first generation
globular cluster.
Boberg O.M., Friel E.D., Vesperini E.
<Astrophys. J., 824, 5-5 (2016)>
=2016ApJ...824....5B 2016ApJ...824....5B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, giant ; Equivalent widths ;
Rotational velocities ; Photometry, UBV
Keywords: Galaxy: abundances; globular clusters: individual: NGC 5024
Abstract:
We present the Fe, Ca, Ti, Ni, Ba, Na, and O abundances for a sample
of 53 red giant branch stars in the globular cluster (GC) NGC 5024
(M53). The abundances were measured from high signal-to-noise medium
resolution spectra collected with the Hydra multi-object spectrograph
on the Wisconsin-Indiana-Yale-NOAO 3.5m telescope. M53 is of interest
because previous studies based on the morphology of the cluster's
horizontal branch suggested that it might be composed primarily of
first generation (FG) stars and differ from the majority of other GCs
with multiple populations, which have been found to be dominated by
the second generation (SG) stars. Our sample has an average
[Fe/H]=-2.07 with a standard deviation of 0.07dex. This value is
consistent with previously published results. The alpha-element
abundances in our sample are also consistent with the trends seen in
Milky Way halo stars at similar metallicities, with enhanced [Ca/Fe]
and [Ti/Fe] relative to solar. We find that the Na-O anti-correlation
in M53 is not as extended as other GCs with similar masses and
metallicities. The ratio of SG to the total number of stars in our
sample is approximately 0.27 and the SG generation is more centrally
concentrated. These findings further support that M53 might be a
mostly FG cluster and could give further insight into how GCs formed
the light element abundance patterns we observe in them today.
Description:
The observations for this study were taken on the
Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope over six nights:
2014 January 20-23, 2014 February 12, 2014 February 13, 2014 February
15. The resulting spectra cover a wavelength range of approximately
6063-6380Å with typical signal-to-noise ratios (S/Ns) of 80-120,
and a dispersion of 0.16Å/pixel (R∼18000).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 73 92 Observational data
table3.dat 36 54 Derived atmospheric parameters
ew.dat 35 3604 Equivalent widths (from table 4) for the
53 red giant members
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/581/A70 : Grid of NLTE EW & NLTE corrections BaII lines (Korotin+, 2015)
J/ApJ/804/109 : Equivalent widths of RGB stars in NGC 5053 (Boberg+, 2015)
J/AJ/149/153 : Abundances of red giants in 10 GCs (Meszaros+, 2015)
J/AJ/149/53 : RVs of 12 Milky Way globular clusters (Kimmig+, 2015)
J/A+A/567/A69 : Radial velocity and photometry in NGC 4372 (Kacharov+, 2014)
J/MNRAS/424/2722 : Variable stars in NGC 5024 (M53) (Bramich+, 2012)
J/AJ/142/126 : CN & CH in SDSS Galactic GCs (Smolinski+, 2011)
J/MNRAS/416/2265 : Variable stars in NGC 5024 (M53) (Arellano Ferro+, 2011)
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/ApJ/681/1505 : Abundances of red giants in ω Cen (Johnson+, 2008)
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/358/547 : M53 variable stars V light curves (Kopacki, 2000)
J/AJ/116/1775 : BV photometry of M53 (Rey+, 1998)
J/PAZh/23/454 : Identification and coordinates in M 53 (Evstigneeva+, 1997)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/132] Identification number (G1)
5- 6 I2 h RAh [13] Hour of Right Ascension (J2000)
8- 9 I2 min RAm [12/13] Minute of Right Ascension (J2000)
11- 15 F5.2 s RAs Second of Right Ascension (J2000)
17 A1 --- DE- [+] Sign of the Declination (J2000)
18- 19 I2 deg DEd [18] Degree of Declination (J2000)
21- 22 I2 arcmin DEm [4/15] Arcminute of Declination (J2000)
24- 28 F5.2 arcsec DEs Arcsecond of Declination (J2000)
30- 34 F5.2 mag Vmag [12.5/15.5] Apparent V band magnitude (G1)
36- 40 F5.2 mag VMag [-3.76/-0.83] Absolute V band magnitude
42- 46 F5.3 mag (B-V)0 [0.04/1.5] Intrinsic (B-V) color index
48- 52 F5.3 mag (V-K)0 [0.1/4.2] Intrinsic (V-K) color index
54- 58 F5.1 km/s RVel [-76.4/370.1]? Radial velocity
60- 63 F4.1 km/s e_RVel [0.7/56]? Uncertainty in RVel
65- 67 I3 --- S/N [48/139]? Signal-to-Noise
69 I1 --- o_RVel [1/5]? Number of observation in RVel
71 A1 --- Mm Member? (75 "Y" and 17 "N")
73 A1 --- f_Mm [b] Flag on Mm (1)
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Note (1):
b = Has a radial velocity consistent with the systemic cluster velocity,
but the spectral analysis did not converge on a solution for the
atmospheric parameters. We consider this star to be a non-member and
possibly a photometric interloper.
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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- 3 I3 --- ID [3/132] Identification number (G1)
9- 12 I4 K Teff [3965/4820] Effective temperature
17- 21 F5.2 --- BCv [-0.8/-0.3] Bolometric correction in V
25- 27 F3.1 [cm/s2] logg [0.5/1.6] Log of surface gravity
33- 36 F4.2 km/s Vt [1.5/2.3] Microturbulent velocity
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Byte-by-byte Description of file: ew.dat
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Bytes Format Units Label Explanations
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1 - 3 I3 --- ID [3/132] Identification number (G1)
5- 7 A3 --- El Species name (Ca, Fe, Ni or Ti) and
ionization: I=neutral
9- 16 F8.3 0.1nm lambda [6082.7/6360.9] Wavelength in Angstroms
18- 23 F6.3 [-] loggf [-6/-0.09] log oscillator strength
25- 29 F5.3 eV EP [0.8/4.8] Potential energy
31- 35 F5.1 0.1pm EW [4.9/191]?=999.9 Equivalent width;
in milli-Angstroms
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Global note:
Note (G1): Identifier and Vmag from Rey et al. 1998, J/AJ/116/1775;
<Cl* NGC 5024 RLB NNNNN> in Simbad
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Aug-2016