Astrophysics researcher

Centro de Estudios de Física del Cosmos de Aragón

Tel. (+34) 978 266 221

aaorsi at cefca dot es


I'm an astrophysics researcher at Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA) in the city of Teruel, Spain. My interests include Galaxy formation and evolution, Large Scale Structure, Semi-analytical models, High redshift galaxies and Lyman-alpha radiative transfer. I obtained a PhD in 2010 from Durham University, UK, under the supervision of Prof. Cedric G. Lacey and Prof. Carlton M. Baugh. My thesis title is "The Nature of Emission-Line galaxies in Hierarchical Cosmologies", and it's available here.

My work is mostly concentrated in predicting galaxy properties from hierarchical models of galaxy formation. The top video on the right illustrates this: High redshift Lyman-alpha emitters (shown in blue) cluster around massive radio galaxies (shown in pink), tracing an underlying dark matter overdensity (gray)

I have developed models for nebular emission in star-forming galaxies by combining radiative transfer and photoionisation codes with semi-analytical models. In order to understand the properties of galaxies detected by their Ly-alpha emission line, I developed a Monte Carlo radiative transfer code of Ly-alpha photons that allows us to predict the escape fraction and line profiles of these photons. The bottom video on the right is a movie I made showing Ly-alpha photons escaping from a spherical neutral gas cloud.

Many large cosmological surveys are currently targeting emission line galaxies (ELGs) to probe the Large Scale Structure of the Universe, particularly at high redshifts. I'm especially interested in characterising the properties of ELGs as cosmological probes. In my latest paper, we demonstrate that capturing the Galaxy Formation mechanisms that shape the galaxy population studied is crucial for modelling their clustering, even on large scales. Specifically, we developed a model to describe satellite kinematics, showing that this leads to and accurate description of the redshift-space clustering down to sub-Mpc scales.

I'm an active member of the J-PAS survey, an ~8500 square degrees survey of the northern sky with 56 optical narrowband filters. Within this collaboration, I coordinate the "Global Galaxy Properties" Science Group. J-PAS will be carried out at the OAJ observatory operated by CEFCA.

The predecessor of J-PAS is J-PLUS. This ongoing survey was originally designed to provide the photometric calibration for J-PAS, but its data allow for multiple science projects from stellar to extragalactic astrophysics. In J-PLUS, I am a member of its Survey Science Committee. I'm also leading a project to detect and characterise z~0.75 ELGs detected by their [OII] 3727 emission..

I am also a member of the Euclid collaboration, ESA's Cosmic Vision space mission to map the geometry of the Universe, and of ATLAS Probe, a concept for a NASA probe-class mission to map the 3D distribution of sources up to very high redshifts.



The slides from my talk at Simulated Skies for new-generation spectroscopic surveys, ESAC, Madrid, 25th of April, 2018.


10th April, 2018

The J-PLUS presentation paper is out!

Check out the preprint of J-PLUS Paper 0, submitted to A&A,. The paper features a description of the instrumental and survey designs, and a brief description of many science cases being actively exploited. As written in the abstract,

"J-PLUS has the potential to contribute to a wide range of fields in Astrophysics, both in the nearby universe (Milky Way, 2D IFU-like studies, stellar populations of nearby and moderate redshift galaxies, clusters of galaxies) and at high redshifts (ELGs at z~ 0.77, 2.2 and 4.4, QSOs, etc)"

7th February, 2018

Workshop announcement

We are very happy to announce a workshop on "Understanding Emission-line galaxies for the next generation of cosmological surveys" to be held in Teruel, Spain, 3-6 of September 2018.

The main goal of this workshop is to bring together and foster collaborations between people working in

i) Current and future cosmological surveys targeting ELGs;

ii) Galaxy formation models and mock catalogues of ELGs, and

iii) Detailed studies of ELGs in the optical + NIR at high redshift.

Detailed information can be found here:…/understanding_emission_line_galaxies

The deadline for registration is the 15th of June.