Ricardo Demarco
Full Professor at Universidad de Concepción (Concepción)
rdemarco [at] astro-udec.cl
I am researcher with about 2 decades of experience as a professional astronomer since the obtention of the Ph.D. (2003), and more than a decade of academic experience as a faculty professor (since 2009). I am interested in the study of galaxies, clusters of galaxies and large-scale structures, in general, in the universe, particularly in the context of galaxy formation and evolution. Most of the work done so far has been focused on high-redshift (z>0.8) galaxies in high-density environments. The main scientific driver of this is to understand the star formation quenching process in galaxies (nature vs. nurture). I am experienced with the acquisition, analysis and interpretation of mainly (rest-frame) optical spectra of galaxies. I am also experienced with imaging observations in the optical and near-IR bands. My direct use of observing facilities includes state-of-the-art infrastructure such as the Very Large Telescope (VLT), Magellan, Gemini South, the Blanco 4-m telescope, the New Technology Telescope (NTT), and the APEX radio-telescope. I have actively participated in international collaborations such as the Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS), the CLASH-VLT spectroscopic survey, the GCLASS spectroscopic survey, and the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. I currently am external collaborator of the Southern Photometric Local Universe Survey (S-PLUS), member of the 4MOST Science Team within the Chilean Cluster Galaxy Evolution Survey (CHANCES), and member of the Galaxies Science Collaboration of the LSST project. I addition to the above, more recently I have become interested in certain aspects of astrobiology, particularly bio-markers and their remote detection, as well as the detection and study of extremophiles on extraterrestrial-analog environments here on Earth.
For more information, visit: http://www.astro-udec.cl/rdemarco/, http://www.astro-udec.cl/rdemarco/En/science_team.html
The Chilean Cluster Galaxy Evolution Survey
CHANCES is one of the 9 extragalactic community surveys approved for 4MOST. Its main goal is to study the evolution of galaxies in and around 150 of the most massive galaxy clusters in the local Universe and out to z~0.4. CHANCES will provide legacy spectroscopic support for the eROSITA X-ray mission, complementing that from the 4MOST Galaxy Clusters Survey, by obtaining spectroscopic redshifts confirming membership for >1000 galaxies per cluster. The survey will provide comprehensive spectroscopic coverage of cluster galaxies both within and well beyond the virial radius, covering the surrounding infall regions out to 5r200 from the cluster. This will permit us to map the hierarchical assembly of the clusters in detail, and measure the importance of pre-processing, where galaxies are transformed within X-ray groups and filaments prior to their arrival into the clusters themselves.
Environmental studies of galaxies with S-PLUS
The "galaxy environment" working group within the S-PLUS collaboration is focused on studying the physical process that drive galaxy evolution in and around galaxy clusters, using data from the Southern Photometric Local Universe Survey (S-PLUS). One specific problem this group is concerned with is to understand the quenching of star formation in galaxies , specially in sub-structures located in the in-falling regions of clusters of galaxies. The S-PLUS main survey covers an area of about 8,000 square degrees of the Southern hemisphere at high Galactic latitudes with a typical photometric depth of r~21 mag. A system of 12 (narrow- and broad-band) filters provides an unparalleled SED sampling for accurate photometric redshifts, and the determination of other physical properties such as stellar masses, star formation rates, and stellar populations of galaxies.
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The CLASH-VLT Survey
The VLT large program "Dark Matter Mass Distributions of Hubble Treasury Clusters and the Foundations of LCDM Structure Formation Models" is a panoramic spectroscopic survey with the VIMOS spectrograph on the VLT of 13 massive clusters of galaxies at z=0.2-0.6 drawn from the "Cluster Lensing and Supernova Survey with Hubble" (CLASH) HST multi-treasury program. The survey was designed to: (i) obtain ~500 spectroscopic members per cluster, over 3-5 Mpc, for an accurate reconstruction of the cluster mass profile from dynamical analysis; (ii) obtain redshifts for high-z magnified galaxies and strong lensing features in the cluster cores out to z~7; and (iii) provide a full spectrophotometric characterization of the largest sample of cluster galaxies to date, with stellar masses ranging from 108 to 1012 solar masses. The CLASH-VLT data set is complemented with observations from Subaru/SupCam, HST, Chandra/XMM. The main scientific objectives of the project are the determination of cluster mass density profiles to constrain dark matter properties, obtain a census of primordial galaxies to study the re-ionization of the Universe, and explore galaxy structure and evolution.
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The GOGREEN Survey
The Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) Survey is built on multi-object spectroscopy of 21 galaxy clusters in the redshift range 1<z<1.5, representing the Universe when it was only a third of its present age. The targets are selected to span a wide range of masses, representing the range of building blocks from which today’s clusters were built. The sample of spectroscopically confirmed members reaches unprecedented stellar masses at this redshift, providing the first look at environmental effects on galaxy evolution at a time when galaxies were growing in a fundamentally different way from today. Our methodology takes full advantage of Hamamatsu detectors, which make Gemini’s GMOS spectrographs the best in the world for studying distant galaxy clusters. GOGREEN spectra allow us to measure the dynamics of different galaxy populations, their stellar populations, and to obtain a robust measurement of the abundance of low-mass, quiescent galaxies.
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