Sergio Vaśquez - Academia.edu (original) (raw)
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Papers by Sergio Vaśquez
Publications of the Astronomical Society of the Pacific, 2015
ABSTRACT We present the first high spectral resolution abundance analysis of two newly discovered... more ABSTRACT We present the first high spectral resolution abundance analysis of two newly discovered Galactic globular clusters, namely Mercer 5 and 2MASS GC02 residing in regions of high interstellar reddening in the direction of the Galactic center. The data were acquired with the Phoenix high-resolution near-infrared echelle spectrograph at Gemini South (R~50000) in the 15500.0 A - 15575.0 A spectral region. Iron, Oxygen, Silicon, Titanium and Nickel abundances were derived for two red giant stars, in each cluster, by comparing the entire observed spectrum with a grid of synthetic spectra generated with MOOG. We found [Fe/H] values of -0.86 +/- 0.12 and -1.08 +/- 0.13 for Mercer 5 and 2MASS GC02 respectively. The [O/Fe], [Si/Fe] and [Ti/Fe] ratios of the measured stars of Mercer 5 follow the general trend of both bulge field and cluster stars at this metallicity, and are enhanced by > +0.3. The 2MASS GC02 stars have relatively lower ratios, but still compatible with other bulge clusters. Based on metallicity and abundance patterns of both objects we conclude that these are typical bulge globular clusters.
We present a study of abundances of two hidden Galactic globular clus- ters: Mercer 5 and 2MASS G... more We present a study of abundances of two hidden Galactic globular clus- ters: Mercer 5 and 2MASS GC02, using high-resolution (IR) spectra. We measure accurate radial velocities of vr = +194 ± 0.3 km s-1 for Mer- cer 5 star 1 and vr = +177 ± 0.3 km s-1 for Mercer 5 star 2. We find [Fe/H] = -1.00 ± 0.02 dex and average a - elements enhancement of +0.40 ± 0.02 dex for Mercer 5, while for 2MASS GC02 we only make a qualitative analysis, due to insufficient signal to noise of the target spectra.
Publications of the Astronomical Society of the Pacific, 2015
ABSTRACT We present the first high spectral resolution abundance analysis of two newly discovered... more ABSTRACT We present the first high spectral resolution abundance analysis of two newly discovered Galactic globular clusters, namely Mercer 5 and 2MASS GC02 residing in regions of high interstellar reddening in the direction of the Galactic center. The data were acquired with the Phoenix high-resolution near-infrared echelle spectrograph at Gemini South (R~50000) in the 15500.0 A - 15575.0 A spectral region. Iron, Oxygen, Silicon, Titanium and Nickel abundances were derived for two red giant stars, in each cluster, by comparing the entire observed spectrum with a grid of synthetic spectra generated with MOOG. We found [Fe/H] values of -0.86 +/- 0.12 and -1.08 +/- 0.13 for Mercer 5 and 2MASS GC02 respectively. The [O/Fe], [Si/Fe] and [Ti/Fe] ratios of the measured stars of Mercer 5 follow the general trend of both bulge field and cluster stars at this metallicity, and are enhanced by > +0.3. The 2MASS GC02 stars have relatively lower ratios, but still compatible with other bulge clusters. Based on metallicity and abundance patterns of both objects we conclude that these are typical bulge globular clusters.
We present a study of abundances of two hidden Galactic globular clus- ters: Mercer 5 and 2MASS G... more We present a study of abundances of two hidden Galactic globular clus- ters: Mercer 5 and 2MASS GC02, using high-resolution (IR) spectra. We measure accurate radial velocities of vr = +194 ± 0.3 km s-1 for Mer- cer 5 star 1 and vr = +177 ± 0.3 km s-1 for Mercer 5 star 2. We find [Fe/H] = -1.00 ± 0.02 dex and average a - elements enhancement of +0.40 ± 0.02 dex for Mercer 5, while for 2MASS GC02 we only make a qualitative analysis, due to insufficient signal to noise of the target spectra.