Dr. Antonio D. Montero-Dorta
I'm an Astrophysicist currently working as a Postdoctoral Research Associate at the Physiscs and Astronomy Department of the University of Utah, in Salt Lake City (USA). I use massive galaxy datasets to investigate the way galaxies evolve in time and to connect the galaxy population to the underlying dark-matter large-scale structure of the Universe. I develop novel statistical techniques to extract information from corrent/next generation cosmological surveys. I also maintain active research interests in other fields, such as stellar population synthesis.
Dark Energy Surveys: The Baryon Oscillation Spectroscopic Survey (BOSS)
MY LATEST RESEARCH: The Evolution of the most massive galaxies in the Universe
During the last years at Utah, my reserach has focused on the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS); the U. of Utah is an important node within the SDSS collaboration. BOSS has mapped the spatial distribution of luminous red galaxies (LRGs) and quasars to detect the characteristic scale imprinted by baryon acoustic oscillations (BAO) in the early universe. Sound waves that propagate in the early universe, like spreading ripples in a pond, imprint a characteristic scale on cosmic microwave background fluctuations. These fluctuations have evolved into today's walls and voids of galaxies, meaning this BAO scale (about 150 Mpc) is visible among galaxies today. The BAO measurement is a powerful tool to constrain the amount of dark matter and dark energy in the Universe.
Due to their unprecedented statistical power (e.g. BOSS has collected ~ 1 million objects), dark energy (DE) surveys (BOSS, eBOSS, Euclid, DES, DESI, LSST, etcetera) have tremendous potential not only to constrain the dark-energy and dark-matter contents of the Universe, but also to shed light into the evolution of the properties and clustering of galaxies. The challenge of optimizing the information that we can extract from massive DE surveys has motivated my research work during the last years.
Dark Energy Surveys: The Baryon Oscillation Spectroscopic Survey (BOSS)
How can we study galaxy evolution using DE surveys?
Realizing the potential of massive, cosmological surveys at high redshift presents significant challenges. These experiments are based on the measurement of specific cosmological features from the large-scale structure, such as the baryon acoustic oscillations (BAO) or the redshift distortions (RD). From these measurements, cosmological parameters can be derived. The current state of the art of precision cosmology dictates the use of huge volumes and large densities (large N) in order to reduce the error bars in cosmological measurements significantly. This, in combination with the high redshift probed, implies low signal-to-noise (S/N) spectra and large photometric errors, which remarkably hinder any galaxy population analysis performed from an object-by-object perspective.
Large photometric errors and low S/N imply that the information that we recieve from individual galaxies come very distorted. This issue, in combination with strong selection effects, produce "observed distributions" of galaxy properties like colors or magnitudes that are not representative of the true, underlying distributions. Extracting these "real" or "intrinsic" distributions of galaxy properties is very important to understand the way galaxies evolve and cluster. I develop new statistical methods within a comprehensive framework of forward-modeling inference to derive intrinsic galaxy-evolution and large-scale structure (LSS) properties of the galaxy populationfrom massive dark energy (DE) galaxy surveys. This properties can then be connected with higher-level theory.
The L-sigma relation between luminosity and the velocity dispersion is an important scaling relation for early-type galaxies. The L-sigma relation at the high-mass range at z=0.55 from BOSS appears to be very similar to that previously measured at z~0 (Montero-Dorta et al. 2015B)
In Montero-Dorta et al. (2015A) we use a novel statistical method to deconvolve the intrinsic red sequence (RS) color-magnitude distribution from photometric errors and selection effects. This method also allow us to compute one of the most fundamental properties of the galaxy population: the luminosity function (LF). The evolution of the RS LF appears to be passive within the redshift range 0.5<z<0.7.