Hi! Welcome to my website.

I am an Associate Proffesor at the Institute of Astrophysics of the Pontificia Universidad Catolica, in Chile.

About Me

I am currently an astronomer at the Institute of Astrophysics of the Pontificia Universidad Catolica in Santiago, Chile. My main research interest is galaxy evolution and specifically the formation and growth of supermassive black holes and its connection to the regulation of star formation on their host galaxies. You can find my CV here in PDF, and a current list of publications here and here: ORCID iD iconhttps://orcid.org/0000-0001-7568-6412.

Research Topics

Black Hole Growth in Major Galaxy Mergers


The growth of supermassive black holes is highly episodic. The triggering mechanisms for these events are still heavily debated. In 2012, we presented observational evidence indicating that while the vast majority of the Active Galactic Nuclei (AGN) are triggered by secular processes, major galaxy mergers are responsible for the most rapid and violent growth episodes, responsible for up to 60% of the total mass gained by supermassive black holes.
I am now very interested in understanding how galaxy mergers trigger black hole growth. To accomplish this, we are studying the physical and dynamical properties of the molecular, neutral and ionized gas in active galaxies undergoing major galaxy mergers. We are doing this using for example the MUSE IFU spectrograph at the VLT and the ALMA array. Examples of our work can be find here and here.

AGN Population Synthesis Models


We use observations of AGN at all wavelengths, but particularly in X-rays, to model the AGN population as a function of parameters such as total luminosity (and hence black hole accretion rate), redshift and amount of obscuration. Among others, these models can explain the observed multiwavelength properties of AGN in deep extragalactic surveys, as we did here, a long time ago.
Another observational constrain for these models come from the Cosmic X-ray Background. Our first models, 15 years ago, were able to explain the spectral shape and intensity of the X-ray background, as presented here. Since then, we updated our model in 2009 to include the hard X-ray survey of the local universe carried out by the Swift satellite using the BAT instrument. More recently, as part of Dr. Tonima Annana PhD thesis, we have constructed and published the most updated AGN population synthesis model to date, now taking into account the deepest Chandra and NuSTAR observations of the X-ray sky to date.

Supermassive Black Hole Seeds in the Early Universe


One of the key open questions about the origin of the supermassive black holes is the nature of their seeds: are they remnants from the first, population III, stars, created by the direct collapse of a large gas cloud, or a combination of these? Observationally, while tens of quasars have been discovered and studied at z>6, the signatures of the seeds in these relatively massive black holes are lost. We have shown that even the deepest X-ray surveys today cannot reach low enough black hole masses to answer this question, which will require to wait for the next generation of X-ray observatories such as Athena and Lynx.
Another observational test of the nature of the first supermassive black hole seeds will be provided by the detection of the gravitational waves generated by their mergers, which will be detected in the next decade by the LISA mission. Together with Dr. Johannes Buchner we created and published a simple but powerful prescription to populate dark matter halos in cosmological simulations in order to trace their merging history and make specific predictions for the expect rate of events that LISA should detect.

Research Team

Current Members

Postdoctoral Fellows


  • Carolina Finlez (2020-2021)
  • Timothy Hewlett (2019-2021)
  • Federica Ricci (2018-2021)
  • Giacomo Venturi (2019-2023)

Graduate students


  • Fernando Penaloza (2019-2020)
  • Dusan Tubin (masters, 2019-2020)
  • Valentina Zagal (masters, 2019-2020)

Past Members

Postdoctoral Fellows


  • Patricia Bessiere (2015-2019)
  • George Privon (2015-2017)
  • Kyle Hiner (2014-2015)
  • Roger Leiton (2013-2015)
  • Yun-Kyeong Sheen (2013-2015)
  • Sabrina Cales (2013-2015)

Graduate students


  • Tonima Ananna (PhD at Yale University, supervised by Prof. Meg Urry, 2015-2019)
  • Lia Sartori (PhD at ETH-Zurich, supervised by Prof. Kevin Schawinski, 2015-2019)
  • Carla Fuentes (masters, 2014-2016)
  • Valeria Olivares (masters, 2014-2015)
  • Caddy Cortes (masters, 2012-2014)

Outreach

I am deeply commited and very passionate about outreach. Typically I give 10+ public talks on topics such as galaxy evolution and mergers, black holes, computational astrophysics, and others. Please do not hesitate to contact me if you would like me to participate in your astronomy outreach event.
As part of our Supermassive Black Holes collaboration we organize every year an astronomy school for professors and an astronomy research competition. In addition, in response to the COVID-19 pandemia, we started a program of weekly interactive astronomy talks. You can find them in our Youtube channel.

Media Apperances

  • ALMA Observations of NGC6240. NRAO Press Release here
  • AAS press release here
  • Several EMOL Op-ed articles here (in spanish)
  • La Clave Radio interview (in Spanish), here
  • Discovery of new exoplanets on Canal 24, here
  • Cooperativa Radio interview (in Spanish) here
  • Galaxy Mergers IfA Hawaii press release here

Contact

Feel free to contact me using the form below: