J/A+A/523/A11 Open clusters towards the Galactic center (Magrini+, 2010)
Open clusters towards the Galactic center: chemistry and dynamics.
A VLT spectroscopic study of NGC6192, NGC6404, NGC6583.
Magrini L., Randich S., Zoccali M., Jilkova L., Carraro G., Galli D.,
Maiorca E., Busso M.
<Astron. Astrophys. 523, A11 (2010)>
=2010A&A...523A..11M 2010A&A...523A..11M
ADC_Keywords: Clusters, open ; Abundances, [Fe/H]
Keywords: Galaxy: abundances - Galaxy: evolution -
open clusters and associations: individual: NGC6192, NGC6404, NGC6583
Abstract:
In the framework of the study of the Galactic metallicity gradient and
its time evolution, we present new high-resolution spectroscopic
observations obtained with FLAMES and the fiber link to UVES at VLT of
three open clusters (OCs) located within ∼7kpc from the Galactic
Center (GC): NGC 6192, NGC 6404, NGC 6583. We also present new orbit
determination for all OCs with Galactocentric distances (Rgc)≤8kpc
and metallicity from high-resolution spectroscopy.
We have derived memberships of a group of evolved stars for each
clusters, obtaining a sample of 4, 4, and 2 member stars in NGC 6192,
NGC 6404, and NGC 6583, respectively. Using standard LTE analysis we
derived stellar parameters and abundance ratios for the iron-peak
elements Fe, Ni, Cr, and for the α-elements Al, Mg, Si, Ti, Ca.
We calculated the orbits of the OCs currently located within 8kpc from
the GC, and discuss their implication on the present-time radial
location.
The average metallicities of the three clusters are all oversolar:
[Fe/H]= +0.12±0.04 (NGC 6192), +0.11±0.04 (NGC 6404), +0.37±0.03
(NGC 6583). They are in qualitative agreement with their
galactocentric distances, being all internal OCs, and thus expected to
be metal richer than the solar neighborhood. The abundance ratios of
the other elements over iron [X/Fe] are consistent with solar values.
The clusters we have analysed, together with other OC and Cepheid
data, confirm a steep gradient in the inner disk, a signature of an
evolutionary rate different than in the outer disk.
Description:
Tables A.1-3: wavelengths, element, and corresponding EW for each
star. Table A.4: EW measured in the solar spectrum, obtained with the
same UVES setup of our observations, containing wavelengths, name of
the element, the excitation potential EP, log (gf), and measured EW in
the solar spectrum.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 84 15 List of stars
tablea1.dat 25 696 Equivalent widths of evolved stars in NGC6192
tablea2.dat 25 421 Equivalent widths of evolved stars in NGC6404
tablea3.dat 25 265 Equivalent widths of evolved stars in NGC6583
tablea4.dat 36 158 Solar equivalent widths
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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- 3 A3 --- --- [NGC]
5- 8 I4 --- NGC Cluster NGC number
10- 13 I04 --- Star Star number in cluster
15- 16 I2 h RAh Right Ascension J2000 (hours)
18- 19 I2 min RAm Right Ascension J2000 (minutes)
21- 25 F5.2 s RAs Right Ascension J2000 (seconds)
27 A1 --- DE- Declination J2000 (sign)
28- 29 I2 deg DEd Declination J2000 (degrees)
31- 32 I2 arcmin DEm Declination J2000 (minutes)
34- 37 F4.1 arcsec DEs Declination J2000 (seconds)
39- 44 F6.3 mag Vmag Johnson V magnitude
46- 50 F5.3 mag V-I V-I color index
52- 57 F6.3 mag Jmag 2MASS J magnitude
59- 64 F6.3 mag Hmag 2MASS H magnitude
66- 71 F6.3 mag Kmag 2MASS Ks magnitude
73- 75 I3 --- S/N Signal to noise ratio (at 650nm)
77- 81 F5.1 km/s RV Radial velocity
83- 84 A2 --- Mm [M NM] Membership (Member of NotMember)
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Byte-by-byte Description of file: tablea[123].dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda Rest frame wavelength
10- 13 A4 --- Ion Ion
15- 18 I04 --- Star Star ID number
20- 25 F6.1 0.1pm EW Equivalent width
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 0.1nm lambda Rest frame wavelength
10- 13 A4 --- Ion Ion
15- 20 F6.3 eV EP Excitation potential
23- 28 F6.3 --- log(gf) Oscillator strengths
31- 36 F6.1 0.1pm EW Equivalent Width
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Acknowledgements:
Laura Magrini <laura(at)arcetri.astro.it>
(End) Laura Magrini [Arcetri Obs.], Francois Ochsenbein [CDS] 23-Aug-2010