Ricardo Demarco's Research

RESEARCH:

My main scientific interest is understanding how the galaxies and clusters of galaxies that we observe in the local universe came to being, as well as their physical properties at different redshifts.

In July 2009, I became a faculty member of the Department of Astronomy of the Universidad de Concepción (UdeC) in Chile, where I established the "Galaxy and Large Scale Structure evolution" (GaLSSev) research group dedicated to the study of clusters of galaxies and their connection with the evolution of galaxies. Since then, this effort has been supported by grants from the FONDECYT (regular category) program of CONICYT, the ALMA fund from CONICYT, and the Joint Committee European Southern Observatory (ESO)-Government of Chile, as well as funding provided by the BASAL Center "Centro de Astrofísica y Tecnologías Afines" (CATA), and UdeC. Over the years, I have gained direct observational experience with facilities such as the VLT, Magellan, Gemini, APEX, and CTIO Blanco telescopes, among others.

A bit of history:

As an undergraduate student at the Department of Astronomy and Astrophysics of PUC, I studied the collapse and formation of structures in the universe, focusing, in particular, on self-similar solutions for the spherical collapse of gas in an Einstein-de Sitter universe (Advisor: Dr. Andreas Reisenegger. See: dissertation).

My Ph.D. research, carried out at the Institut d'Astrophysique de Paris (IAP) and the European Southern Observatory (ESO) in Garching, took an observational approach instead, dedicated to the study of the physical properties of baryons in nearby and distant clusters of galaxies (Advisors: Dr. Florence Durret [IAP] and Dr. Piero Rosati [ESO]. See: Ph.D. dissertation).

At present:

Currently, my main research is dedicated to the analysis and interpretation of imaging and spectroscopic data sets from ground- and space-based observatories to investigate structure formation and evolution. In particular, the analysis of spectroscopic data allows me to map out large-scale structures (groups and clusters), study galaxy cluster dynamics and characterize the stellar content of galaxies in and around high-density environments out to z~1-2. In combination with accurate photometry and high angular resolution data, it is possible to investigate the stellar mass assembly history of galaxies and the effects of the environment on galaxy properties.

As a member of the SpARCS (PI.: G. Wilson), GCLASS (PI: A. Muzzin), and GOGREEN (PI.: M. Balogh) collaborations, I am involved in the study of galaxy clusters at z>0.8 and the search for clusters at z>1.5 to investigate the transition of these structures from protoclusters at z>2 to massive clusters at z<1, and the quenching of star formation in galaxies. I am also part of the CLASH-VLT survey, a VLT Large Program (PI.: P. Rosati) to carry out a panoramic spectroscopic survey of massive clusters at z=0.2-0.6, drawn from the sample of the CLASH HST multi-treasury program (PI.: M. Postman). This project is intended to probe the structure, mass distrubution and evolution of clusters, and obtain a census of primordial galaxies to explore the growth of structures in the early universe. In addition to the above, since 2019, I am an external collaborator of the Southern Photometric Local Universe Survey (S-PLUS; PI: Claudia Mendes de Oliveira), where I focus on galaxy properties and quenching in nearby clusters. And since 2021, I am a member of the 4MOST Science Team within the Chilean Cluster Galaxy Evolution Survey (CHANCES; PI: Chris Haines). This survey is intended to obtain ~300.000 spectra of galaxies in 150 clusters to study, among other interesting subjects, the pre-processing of galaxies that are incorporated into the cluster environment from large clustercentric distances.

Last but not least, I participate in the Galaxies Science Collaboration of the Legacy Survey of Space and Time (LSST) with the Simonyi Survey Telescope at the Vera Rubin Observatory, and in the data-science group (PI: Prof. G. Cabrera-Vives) of the Department of Computer Engineering at UdeC, specifically in the subgroup of Astroinformatics. I am also associate researcher of the Area-3 (Galaxies) of the Center for Astrophysics and Associated Technologies (CATA; PI: Prof. G. Garay).

People:

At present, I work directly with a few students from UdeC (see below). My group (GaLSSev) is part of a bigger research environment within our Department of Astronomy including professors Neil Nagar, Rodrigo Herrera-Camus, and Nathan Leigh. With them and their postdocs and students, we form the larger Extragalactic Astronomy Group at UdeC, including topics on AGN physics, sub-millimeter galaxies and radioastronomy, in addition to those mentioned above. I am also involved with Profs. Guillermo Cabrera-Vives and Pierluigi Cerulo, from the Department of Computer Science at UdeC, in research projects combining advanced computational techniques and large astronomical data sets to study galaxy formation and evolution.

My collaborators outside UdeC include: Prof. Michael Balogh (Univ. of Waterloo), Prof. Scott Fisher (Univ. of Oregon), Dr. Hector Flores (Obs. of Paris), Prof. Raphael Gobat (PUCV), Prof. Facundo Gómez (Univ. de La Serena), Prof. Lucia Guaita (UNAB), Prof. Chris Haines (Univ. de Atacama), Prof. Yara Jaffé (UV), Dr. Patricio Lagos (Univ. of Porto), Prof. Chris Lidman (ANU/Siding Spring Obs.), Prof. Claudia Mendes de Oliveira (Univ. of Sao Paulo), Dr. Hugo Messias (ALMA), Prof. Julie Nantais (UNAB), Dr. Mario Nonino (Obs. of Trieste), Dr. Priscilla Nowajewski (ALMA), Prof. Daniela Olave-Rojas (Univ. of Talca), Dr. Alessandro Rettura (JPL), Prof. Piero Rosati (Univ. of Ferrara), Prof. Greg Rudnick (Univ. of Kansas), Prof. James Schombert (Univ. of Oregon), Dr. Veronica Strazzullo (LMU), Prof. Sergio Torres (Univ. de La Serena), Dr. Eelco van Kampen (ESO/ALMA), and Prof. Gillian Wilson (UC Merced), among others.

Students from UdeC currently working with me (as advisor or co-advisor) are:

• Pablo Astudillo (graduate - master; expected to graduate: 2023)
• Camila Cid (graduate - master; expected to graduate: 2023)
• Matías Espinoza (graduate - master; expected to graduate: 2023)
• Benjamín González (graduate - master; expected to graduate: 2023)
• Diego Salvador (graduate - master; expected to graduate: 2023)
• Kamilla Barra (B.S.)
• Jorge Cortés (B.S.)
• Javiera Fuentes (B.S.)
• Iriel González (B.S.)
• Nicolás Henríquez (B.S.)
• Gustavo Iturra (B.S.)
• Felipe Oyarzo (B.S.)
• Antonia Salinas (B.S.)

International students currently working with me are:

• Marcela G. Paillalef (graduate; Ph.D. student at Obs. of Paris, France)

Postdocs who have previously worked (under my supervision) with me:

• Dr. Julie Nantais (Ph.D. Harvard University), at UdeC: 2010-2014
Currently assistant professor at Universidad Andrés Bello, Santiago, Chile

• Dr. Hugo Messias (Ph.D. Lisbon University), at UdeC: 2011-2013
Currently ALMA DSO Astronomer at ALMA Vitacura, Chile

• Dr. Yun-Kyeong Sheen (Ph.D. Yonsei University), at UdeC: 2012-2015
Currently staff astronomer at KASI, South Korea

• Dr. Yara Jaffé (Ph.D. University of Nottingham), at UdeC: 2012-2015
Currently assistant professor at Universidad de Valparaíso, Valparaíso, Chile

• Dr. Pierluigi Cerulo (Ph.D. Swinburne University), at UdeC: 2015-2020
Currently assistant professor at the Computer Science Dept., Univ. de Concepción, Concepción, Chile

• Dr. Clément Martinache (Ph.D. Paris University), at UdeC: 2017-2020
Currently out of astronomy

Left: posing during a long integration observation with the Magellan/Baade telescope at the Las Campanas Observatory in the Chilean Andes (© Alessandro Rettura & R. Demarco). Right: me at the control room of the Magellan/Baade telescope observing clusters of galaxies in the near infrared with the FourStar instrument (© Pierluigi Cerulo).