A5077675007- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Astronomical and nuclear sciences
- Calibration and Measurement Techniques
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
- Historical Astronomy and Related Studies
- Infrared Target Detection Methodologies
- Solar and Space Plasma Dynamics
- Scientific Measurement and Uncertainty Evaluation
- Optical Polarization and Ellipsometry
- Molecular spectroscopy and chirality
- Tribology and Lubrication Engineering
- Advanced Semiconductor Detectors and Materials
- Veterinary Equine Medical Research
- Plant Toxicity and Pharmacological Properties
- Optical measurement and interference techniques
University of Concepción
2015-2024
Millennium Institute of Astrophysics
2015-2023
Universidad Nacional de Concepción
2014
Ludwig-Maximilians-Universität München
2013
Bayerische Staatssammlung für Paläontologie und Geologie
2013
Max Planck Institute for Extraterrestrial Physics
2013
University of Chile
2011
University of Warsaw
2009
Pontificia Universidad Católica de Chile
1992-2009
University of Hawaiʻi at Mānoa
2009
Context. The ESO public survey VISTA variables in the Vía Láctea (VVV) started 2010. VVV targets 562 sq. deg Galactic bulge and an adjacent plane region is expected to run for about five years.
We have obtained new spectrophotometric data for 28 H ii regions in the spiral galaxy NGC 300, a member of nearby Sculptor Group. The detection several auroral lines, including [O iii] λ4363, [S λ6312, and [N ii] λ5755, has allowed us to measure electron temperatures direct chemical abundances whole sample. determine first time this radial gas-phase oxygen abundance gradient based solely on obtain following least-square solution: 12 + log(O/H) = 8.57(±0.02) − 0.41(±0.03)R/R25, where...
We have determined parameters and abundances for three SMC nine LMC Cepheids that not been previously studied spectroscopically metallicity, as well one observed by Luck & Lambert. This work nearly doubles the number of with spectroscopic metallicities in triples LMC. For Galactic reference stars we 11 supergiants spectral type F0 to K1. These are used herein examine dispersion cosmic [Fe/H] values found Lambert, later papers will be correct distance moduli obtained us these using visual...
Aims. We determine period-luminosity relations for Milky Way Cepheids in the optical and near-IR bands. These can be used directly as reference extra-galactic distance determination to Cepheid populations with solar metallicity, they form basis a direct comparison obtained exactly same manner stars Magellanic Clouds, presented an accompanying paper. In that paper we show metallicity effect is very small consistent null effect, particularly bands, combine here all 111 from Way, LMC SMC best relation.
We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by Optical Gravitational Lensing Experiment (OGLE) survey. The components show negligible intrinsic variability. A consistent set stellar parameters was derived with low statistical and systematic uncertainty. absolute dimensions stars are calculated precision better than 3%. surface brightness–infrared color relation used derive...
A quantitative spectral analysis of 24 supergiants in the Sculptor Group spiral galaxy NGC 300 at a distance 1.9 Mpc is presented. new method introduced to analyze low-resolution (~5 Å) spectra, which yields metallicities accurate 0.2 dex including uncertainties arising from errors Teff (5%) and log g (0.2 dex). For first time stellar metallicity gradient based on elements such as titanium iron beyond Local investigated. Solar measured center 0.3 solar outskirts logarithmic –0.08 kpc−1. An...
We develop, implement and characterise an enhanced data reduction approach which delivers precise, accurate, radial velocities from moderate resolution spectroscopy with the fibre-fed VLT/FLAMES+GIRAFFE facility. This facility, appropriate care, adequate to resolve intrinsic velocity dispersions of very faint dSph dwarf galaxies. Importantly, repeated measurements let us reliably calibrate our individual errors ($0.2 \leq \delta_V\leq 5$ km s$^{-1}$) directly detect stars variable...
We present spectra of 14 A-type supergiants in the metal-rich spiral galaxy M83. derive stellar parameters and metallicities, measure a spectroscopic distance modulus m-M = 28.47 +\- 0.10 (4.9 0.2 Mpc), agreement with other methods. use characteristic metallicity M83 systems to discuss version mass-metallicity relation that is independent analysis nebular emission lines associated systematic uncertainties. reproduce radial gradient M83, which flattens at large radii, chemical evolution...
We present a photometric investigation of the globular cluster population NGC 1399, central galaxy in Fornax cluster, Washington C and Kron R filters within field 36' × 36', corresponding to about 200 kpc at distance. This is largest area around this ever studied with CCD photometry. The system 1399 found extend farther than 100 away from galaxy. color distribution exhibits pronounced bimodality. Within radial distance 55 kpc, red clusters are more strongly concentrated toward center blue...
We have used the infrared Barnes-Evans surface brightness technique to derive radii and distances of 34 Galactic Cepheid variables. Radius distance results obtained from both versions are in excellent agreement. The 28 variables determine period-radius (PR) relation. This relation is found a smaller dispersion than previous studies, identical PR by Laney & Stobie completely independent method, fact which provides persuasive evidence that now determined at very high confidence level. use...
We present new period-age (PA) and period-age-color (PAC) relations for fundamental first-overtone classical Cepheids. Current predictions rely on homogeneous sets of evolutionary pulsation models covering a broad range stellar masses chemical compositions. found that PA PAC mild dependence metal content. Moreover, the use different Cepheids improves accuracy age estimates in short-period (log P < 1) (old Cepheids), because they smaller intrinsic dispersions. At same time, long-period ≥...
We report the independent discovery of a new extrasolar transiting planet around OGLE-TR-113, candidate star from Optical Gravitational Lensing Experiment. Small radial velocity variations have been detected based on observations conducted with MIKE spectrograph Magellan I (Baade) telescope at Las Campanas Observatory (Chile) during 2003. also carried out light-curve analysis incorporating photometry and realistic physical parameters for star. OGLE-TR-113b has an orbital period only 1.43...
As a continuation of our previous work on the abundance gradient in outer part galactic disc, this paper presents results metallicicty distribution over galactocentric distances up to 15 kpc. The disc is clearly separated from middle by existence step metallicity at about 10 Taking region kpc kpc, one can derive an iron dex kpc-1 (25 stars). discontinuity be caused effective suppression mixing processes near corotation circle where radial component gas velocity should very small.
We have obtained deep near-infrared images in J and K filters of three fields the Sculptor galaxy NGC 300 with ESO VLT ISAAC camera. For 16 Cepheid variables these fields, we determined magnitudes at two different epochs, derived their mean bands. The slopes resulting period-luminosity relations are very good agreement measured LMC by Persson et al. Fitting to our data, distance moduli K. Using values together optical V I bands previous work, an improved total reddening for E(B-V)=0.096 +/-...
The extragalactic distance scale builds directly on the Cepheid Period-Luminosity (PL) relation as delineated by sample of Cepheids in Large Magellanic Cloud (LMC). However, LMC is a dwarf irregular galaxy, quite different from massive spiral galaxies used for calibrating scale. Recent investigations suggest that not only zero-point but also slope Milky Way PL differ significantly LMC, casting doubts universality relation. We want to make differential comparison relations two delineating...
This paper reports on the spectroscopic investigation of 101 Cepheids in Carina region. These extend previous samples by about 35% number and increase amount Galactic disk coverage especially direction l ≈ 270°. The new do not add much information to radial gradient, but provide a substantial azimuthal coverage. We find no dependence abundance over an 80° angle from center annulus 1 kpc depth centered Sun. A simple linear fit Cepheid data yields gradient d[Fe/H]/dRG = −0.055 ± 0.003 dex...
Long-baseline interferometry is an important technique to spatially resolve binary or multiple systems in close orbits. By combining several telescopes together and spectrally dispersing the light, it possible detect faint components around bright stars. Aims. We provide a rigorous detailed method search for high-contrast companions stars, determine detection level, estimate dynamic range from interferometric observations. developed code CANDID (Companion Analysis Non-Detection...
The quantitative spectral analysis of low resolution Keck LRIS spectra blue supergiants in the disk giant spiral galaxy M81 is used to determine stellar effective temperatures, gravities, metallicities, luminosites, interstellar reddening and a new distance using Flux-weighted Gravity--Luminosity Relationship (FGLR). Substantial extinction found with E(B-V) ranging between 0.13 0.38 mag an average value 0.26 mag. modulus obtained after individual corrections 27.7+/-0.1 result discussed...
A novel method of analysis double-lined eclipsing binaries containing a radially pulsating star is presented. The combined pulsating-eclipsing light curve built up from purely grid created using an existing modeling tool. For every pulsation phase the instantaneous radius and surface brightness are taken into account, being calculated disentangled radial velocity its out-of-eclipse pulsational ratio components, respectively. best model found Markov Chain Monte Carlo method. applied to binary...
The extragalactic distance scale builds on the Cepheid period-luminosity (PL) relation. In this paper, we want to carry out a strictly differential comparison of absolute PL relations obeyed by classical Cepheids in Milky Way (MW), LMC and SMC galaxies. Taking advantage substantial metallicity difference among populations these three galaxies, establish possible systematic trend relation zero point as function metallicity, determine size such an effect optical near-infrared photometric...