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J/ApJ/695/L134   Chemical anomalies in old LMC clusters   (Mucciarelli+, 2009)

Looking outside the galaxy: the discovery of chemical anomalies in three old Large Magellanic Cloud clusters. Mucciarelli A., Origlia L., Ferraro F.R., Pancino E. <Astrophys. J., 695, L134-L139 (2009)> =2009ApJ...695L.134M
ADC_Keywords: Equivalent widths ; Clusters, globular ; Magellanic Clouds ; Spectroscopy ; Abundances ; Stars, giant Keywords: globular clusters: individual (NGC 1786, NGC 2210, NGC 2257) - Magellanic Clouds - techniques: spectroscopic Abstract: By using the multifiber spectrograph FLAMES mounted at the ESO-VLT, we have obtained high-resolution spectra for 18 giant stars, belonging to three old globular clusters of the Large Magellanic Cloud (namely NGC 1786, 2210, and 2257). While stars in each cluster showed quite homogeneous iron content, within a few cents of dex (the mean values being [Fe/H]=-1.75±0.01dex, -1.65±0.02dex and -1.95±0.02dex for NGC 1786, 2210, and 2257, respectively), we have detected significant inhomogeneities for the [Na/Fe], [Al/Fe], [O/Fe], and [Mg/Fe] abundance ratios, with evidence of [O/Fe] versus [Na/Fe] and [Mg/Fe] versus [Al/Fe] anticorrelations. The trends detected nicely agree with those observed in Galactic Globular Clusters, suggesting that such abundance anomalies are ubiquitous features of old stellar systems and they do not depend on the parent galaxy environment. In NGC 1786 we also detected two extreme O-poor, Na-rich stars. This is the first time that a firm signature of extreme chemical abundance anomalies has been found in an extragalactic stellar cluster. Description: 18 giants located in three old LMC clusters (NGC 1786, 2210, and 2257) have been observed with FLAMES at the ESO-VLT telescope (ID Proposal 080.D-0368(A)). The target stars have been selected along the red giant branch of IR color-magnitude diagram (A. Mucciarelli et al., 2010, Cat. J/ApJ/717/277) with typical K0∼12.8-13.5 magnitudes and (J-K)0∼0.6-0.8 colors. All the targets have been observed with the UVES Red Arm (covering the ∼4800-6800Å wavelength range) and the HR 11 and HR 13 GIRAFFE/MEDUSA setups (covering the 5600-5840Å and 6120-6400Å ranges, respectively). The spectra have been acquired in series of 8-9 exposures of ∼45 minutes each. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 50 18 Information about the target stars from Mucciarelli et al. 2010, Cat. J/ApJ/717/277 table1.dat 44 1452 Atomic data and equivalent widths for the sample stars
See also: VI/110 : Final Merged Log of IUE Observations (NASA-ESA, 2000) VII/183 : The Cluster System of the LMC (Kontizas+ 1990) J/ApJ/717/277 : Chemical composition of old LMC clusters (Mucciarelli+, 2010) J/AJ/136/375 : Chemical composition of LMC red giants (Mucciarelli+, 2008) J/AJ/132/1630 : CaII spectroscopy in Magellanic Cloud clusters (Grocholski+, 2006) J/ApJ/611/270 : Magellanic star clusters IR fluctuations (Gonzalez+, 2004) J/AJ/98/2086 : CCD photometry of NGC 2257 RR Lyrae (Walker 1989) Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 3 A3 --- --- [NGC] 5- 13 A9 --- Name Giant star name (NNNN-NNNN) 15- 19 F5.1 km/s HRV Heliocentric velocity 21- 25 F5.2 mag K0mag Dereddened K0-band magnitude 27- 36 F10.7 deg RAdeg Right ascension in decimal degrees (J2000) 38- 48 F11.7 deg DEdeg Declination in decimal degrees (J2000) 50 A1 --- Inst [UG] Adopted instrumental configuration (U for UVES and G for GIRAFFE spectra)
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Name Giant star name (NNNN-NNNN) 11- 15 A5 --- Ion Ion identification 17- 23 F7.2 0.1nm Wave Wavelength in Angstroms 25- 28 F4.2 eV ExPot Excitation potential 30- 35 F6.2 [-] log(gf) Log of the oscillator strength 37 A1 --- l_EW Limit flag on EW 38- 42 F5.1 10-13m EW ? Equivalent width in mÅ 44 A1 --- f_EW [s] "s" if obtained from spectral synthesis
History: * 04-Apr-2011: From electronic version of the journal * 26-May-2011: Names in table1 corrected to be in agreement with the other paper (Mucciarelli et al. 2010, J/ApJ/717/277): - 2210-1228 transformed into 2210-122 - 2257-862 transformed into 2257-842 References: Ferraro et al. Iron Content of NGC 1978 in the LMC. 2006ApJ...645L..33F Mucciarelli et al. Chemical composition of LMC red giants. 2008AJ....136..375M Cat. J/AJ/136/375 Mucciarelli et al. Chemical composition of three old LMC clusters. 2010ApJ...717..277M Cat. J/ApJ/717/277
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Apr-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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