Papers by Marcela Espinoza Contreras
Soi/soar Search For Short-Period Variable Stars In The Open Cluster Ngc 6531
In this work we report preliminary results of a search for shortperiod variable stars in the open... more In this work we report preliminary results of a search for shortperiod variable stars in the open cluster NGC 6531. In particular we looked for new roAp, Delta-Scuti and gamma-Doradus stars. We collected high-precision V-Bessel time-series data with the SOAR Optical Imager (SOI) at the SOAR 4.1m telescope. The data were reduced using a custom pipeline based on IRAF/PyRAF and the final light-curves were analyzed using discrete Fourier transforms (DFT). The periods and the preliminary classifications of five newly discovered variables are discussed.
Raman-scattered laser guide-star photons to monitor the scatter of astronomical telescope mirrors
Astronomy & Astrophysics
The first observations of laser guide-star photons that are Raman-scattered by air molecules abov... more The first observations of laser guide-star photons that are Raman-scattered by air molecules above the Very Large Telescope (VLT) were reported in June 2017. The initial detection came from the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph, following the installation of the 4 Laser Guide Star Facility (4LGSF) on Unit Telescope 4 (UT4) of the VLT. In this Letter, we delve further into the symbiotic relationship between the 4LGSF laser guide-star system, the UT4 telescope, and MUSE by monitoring the spectral contamination of MUSE observations by Raman photons over a 27-month period. This dataset reveals that dust particles deposited on the primary and tertiary mirrors of UT4, which are responsible for a reflectivity loss of ∼8% at 6000 Å, contribute (60 ± 5)% to the laser line fluxes detected by MUSE. The flux of Raman lines, which contaminates scientific observations that are acquired with optical spectrographs, thus provides a new, non-invasive means t...
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Papers by Marcela Espinoza Contreras