Oscar Hernandez Utrera

Universidad Nacional Autónoma de México | UNAM · Centro de Nanociencias y Nanotecnología

We present a thorough study of the target-cleaning phase to estimate the healthiness of the target in a direct current (DC) magnetron sputtering deposition. The study is based on real-time plasma monitoring by means of optical emission spectroscopy during a traditional cleaning phase in an Ar atmosphere. In this work we demonstrate that intensities...

The Cananea near-infrared camera (CANICA) is an instrument commissioned at the 2.12m telescope of the Guillermo Haro Astrophysical Observatory (OAGH) located in Cananea, Sonora, México. CANICA operates in the near-infrared at multiple bands including J(1.24 μm), H(1.63 μm) and K ' (2.12 μm) broad-bands. CANICA in located at the Ritchey-Chrétien foc...

The Cananea near-infrared camera (CANICA) is an instrument commissioned at the 2.12 m telescope of the Guillermo Haro Astrophysical Observatory (OAGH) located at Cananea, Sonora, M´exico. CANICA operates in the near-infrared at multiple bands including J(1.24 µm), H(1.63 µm) and K 0 (2.12 µm) broad-bands. CANICA is located at the Ritchey-Chr´etien...

Context. The signal processing of multi-aperture monomode interferometers using multiaxial recombination, such as AMBER/VLTI, makes use of the modeling of the fringes in the image space called the “P2VM method”. This method was only validated on simulated data.Aims. We aim to validate the P2VM method on-sky, and to use the knowledge acquired during...

The apparent size and greater luminosity of Red Super Giant stars (RSGs) make them ideal targets for astrometry experiments. Since the observation of Betelgeuse by Michelson & Pear (1921), several other works have been carried out improving the precision on the measurement of the diameter of the star (e.g., Weiner et al. 2000; Young et al. 2000). W...

Aims. This paper describes the design goals and engineering efforts that led to the realization of AMBER (Astronomical Multi BEam combineR) and to the achievement of its present performance. Methods. On the basis of the general instrumental concept, AMBER was decomposed into modules whose functions and detailed characteristics are given. Emphasis i...

We present here the current performances of the AMBER / VLTI instrument for standard use and compare these with the offered modes of the instrument. We show that the instrument is able to reach its specified precision only for medium and high spectral resolution modes, differential observables and bright objects. For absolute observables, the curre...

Aims. We present the first NIR spectro-interferometry of the LBV $\eta$ Carinae. The observations were performed with the AMBER instrument of the ESO Very Large Telescope Interferometer (VLTI) using baselines from 42 to 89 m. The aim of this work is to study the wavelength dependence of $\eta$ Car's optically thick wind region with a high spatial r...

Aims.We study the geometry and kinematics of the circumstellar environment of the Be star $\kappa$ CMa in the Br$\gamma$ emission line and its nearby continuum.Methods.We use the AMBER/VLTI instrument operating in the $K$ band, which provides a spatial resolution of about 6 mas with a spectral resolution of 1500, to study the kinematics within the...

Context.Optical long-baseline interferometry is moving a crucial step forward with the advent of general-user scientific instruments that equip large aperture and hectometric baseline facilities, such as the Very Large Telescope Interferometer (VLTI).Aims.AMBER is one of the VLTI instruments that combines up to three beams with low, moderate and hi...

Aims.We investigate the origin of the ${\rm Br}\gamma$ emission of the Herbig Ae star HD 104237 on Astronomical Unit (AU) scales.Methods.Using AMBER/VLTI at a spectral resolution $\mathcal{R}=1500$ we spatially resolve the emission in both the ${\rm Br}\gamma$ line and the adjacent continuum.Results.The visibility does not vary between the continuu...

Aims.In this paper, we present an innovative data reduction method for single-mode interferometry. It has been specifically developed for the AMBER instrument, the three-beam combiner of the Very Large Telescope Interferometer, but it can be derived for any single-mode interferometer.Methods.The algorithm is based on a direct modelling of the fring...

In this work, we present the first AMBER observations, of the Wolf-Rayet and O (WR+O) star binary system y2 Velorum. The AMBER instrument was used with the telescopes UT2, UT3, and UT4 on baselines ranging from 46m to 85m. It delivered spectrally dispersed visibilities, as well as differential and closure phases, with a resolution R = 1500 in the s...

Aims. In this paper, we present an innovative data reduction method for single-mode interferometry. It has been specifically developed for the AMBER