Recent Talks

The immediate surroundings of our Milky Way galaxy are home to a number of dwarf galaxies, whose variety in shape, size, spatial location and velocity tells us that these Galactic satellites all have different tales to tell. While some look round, pristine and undisturbed, others have disturbed morphologies or show gradients in their metallicity, while yet others have unusual kinematic features or clearly show their dissolution into a stellar stream. Very few of them contain significant levels of gas, also prompting the question of what mechanism is responsible for stripping out their gas content. This talk will explore the eclectic mix of Milky Way dwarf galaxies and what their properties can reveal to us about their different stories, and also what they can collectively tell us of our own Galaxy. I will also discuss how looking at the Galactic vicinity is aiding us, via this population of Galactic satellites, in the increasingly popular area of near-field cosmology.

Little is known about the mid-infrared (MIR) polarization at high-angular resolution of Active Galactic Nuclei (AGN), however, the polarimetric mode of CanariCam on the 10.4-m Gran Telescopio CANARIAS has opened a new window to reveal its core. We have found a variety of results: 1) A Highly polarized synchrotron emission in the core of Cygnus A; 2) a very complex MIR polarization structures in and around the core of NGC 1068; and 3) a very low polarized core of Mrk 231. In this talk, I will present new CanariCam polarimetric results on several AGN which provide key information on our understanding of the AGN structure and jet formation.

MASTER-Kislovodsk auto-detection system discovered a faint transient in the Andromeda galaxy on January 13th 2015. It was originally identified as a classical nova and received designation M31N 2015-01a. Further observations showed discrepancies with the spectra and lightcurves typical for the classical novae. The transient was re-identified as a likely stellar merger (aka Luminous Red Nova (LRN)), similar to V838Mon. In this presentation I will deliver a short overview of our current understanding of this class of objects and a summary of the current state of the ongoing observing campaign of the M31 LRN. Recent results will be discussed with a particular emphasis on the contributions made possible by GTC and other observing facilities at Observatorio Roque de los Muchachos. At the final part of the presentation I will touch on follow up observations once M31 is available for observations again.

 I will present a multiwavelength study of a large MIPS selected galaxies and satisfy a certain IRAC color criterion. Stellar population modeling and IRS spectra together demonstrate that the double criteria used to select this sample have efficiently isolated massive star-forming galaxies at /z/ ~ 1.9. This is the first starburst (SB)-dominated ultraluminous infrared galaxies (ULIRG) sample at high redshift with total infrared luminosity measured directly from Spitzer, Herschel FIR and millimeter photometry, and as such gives us the first accurate view of broadband spectral energy distributions for SB galaxies at extremely high luminosity and at all wavelengths. The HST images in optical and NIR bands show that most objects have very extended morphologies in the rest-frame ultraviolet and optical band, thus extended distribution of PAH molecules. We conclude that objects in this sample are ULIRGs powered mainly by SB; and the total infrared luminosity density contributed by this type of objects at /z/ ~ 1.9.

En el mundo romano, a la hora de crear una nueva ciudad, un parcelario rural, un campamento, era necesario tener el parabien de los dioses, hecho que se conseguía mediante el rito de fundación. En este ceremonial, entre otras cosa, se marcaba sobre el suelo una figura compuesta por dos líneas que se cortaban perpendicularmente, señalando respectivamente, la linea norte-sur y este-oeste. Estas dos alineaciones marcaban, teóricamente, las direcciones de los dos ejes principales de los trazados romanos: el cardo y el decumano. La realidad es que esa orientación hacia los puntos cardinales se dio en pocas ocasiones; causas simbólicas y rituales, cuestiones prácticas y funcionales, hicieron que a los trazados se les concedieran otras alineaciones. Cómo dibujar en el suelo orientaciones que no siguen los ejes cardinales, y teniendo en cuenta los medios con los que se contaba en ese período histórico es la temática en la que versará este seminario, en donde la descripción de la técnica definida por el agrimensor Nipsius, la varatio, va a ser la base de la explicación a uno de los plausibles procedimientos utilizado para conferir al entramado que se quiera construir, la orientación que se consideró la más adecuada para ese lugar.

In the past years, intensive Site Characterization campaigns have been performed to chose the sites for the future giant ELTs. Various atmospheric turbulence profilers with different resolution and sensed altitude ranges have been used, as well as climatological tools and satellite data analysis. Mixing long term statistics at low altitude resolution with high resolution data collected during short term campaigns allows to produce the reference profiles as input to the Adaptive Optics (AO) instrument performance estimators. In this talk I will perform a brief review of the principal and most used instruments and tools in order to give to the audience a panorama of the work and the efforts to monitor the atmospheric turbulence for astronomical purposes.

SDSS-III and its four surveys, BOSS, SEGUE-2, MARVELS and APOGEE, came to an end in June 2014, and all data were publicly released last January. The IAC participation as a full member spanned all surveys, and has driven an increase in the use of SDSS data at the IAC: about 15 % of the papers published by the IAC (and about 30% of its citations) in 2010-2014 involve the use of SDSS data.SDSS-IV started immediately after SDSS-III ended, with three new surveys, eBOSS, APOGEE-2, and MaNGA. The IAC continues in the collaboration as the sole full institutional member in Spain, and one of the few in Europe. We will provide an update on SDSS-IV, and bring some the IAC researchers working on SDSS to tell us first hand about their science.

With the aim of testing the relation between supernova (SN) rate and star formation rate, we conducted a SN search in a sample of local starburst galaxies (SBs) where both star formation rates and extinction are extremely high. The search was performed in the near-infrared, where the bias due to extinction is reduced using HAWK-I on the VLT. We discovered six SNe, in excellent agreement with expectations, when considering that, even in our search, about 60% of events remain hidden in the nuclear regions due to a combination of reduced search efficiency and very high extinction.
In addition I will present my plans for next months at IAC for the "Starbursts and EMIR project". I will participate in the commissioning of the instrument at La Palma, collaborating in the development of the ETC and I  will compile a catalog of starbursts for EMIR with the aim to study their imprint in the cosmic evolution of galaxies.

Current scientific cosmology hosts a plurality of scenarios that articulate in different ways the precision astronomy's observations. However, this palette of alternatives is not taken as the true scientific production. There is a monist tendency to think that scientific results should be represented by a single scenario. The present work seeks to undermine the attempts to justify that tendency and to show that even if a single and final stage is waiting, methodological pluralism also would be the best option to achieve it.

Our Universe is filled with a mind-blowing diversity and different types and appearances of galaxies. Finding out about how they formed and evolved is one of the most challenging tasks in astronomy. When looking about 10 billion years back, to an epoch about 3 billion years after the big bang, we can see galaxies at earlier stages of their lives. In this talk, studies of different kinds of galaxies in the early universe will be presented. Two examples of the very intriguing population of massive quiescent z~2 galaxies were analyzed in terms of their stellar populations and morphologies. As the spectroscopic sample is still small, especially for galaxies at the faint end of the luminosity function, we make use of the biggest available "telescopes" in the universe: We search for red z~2 galaxies whose apparent brightnesses have been boosted by the Gravitational Lensing effect of intermediate redshift galaxy clusters with available mass models. Our findings indicate older ages for these galaxies than expected. Also, their remarkable compactness was corroborated. Furthermore, I'm going to present a study of a special case of so-called Damped Lyman-alpha Absorbers (DLAs), with two intervening galaxies in the line of sight of a higher-redshift QSO, which is also one example of only about a dozen known galaxy counterparts of a DLA. It fits into the emerging paradigm that galaxies which are responsible for higher metallicity DLAs are more massive and luminous than typical DLA galaxies. Motivated by that particular discovery, during the past few years we have undertaken a survey targeting candidate dust-reddened quasars missing in the sample from Sloan Digital Sky Survey. Spectroscopic follow-up with the NOT and the NTT has demonstrated a very high success rate of our selection (>90%). The main motivation is to search for quasars reddened by foreground dusty galaxies and we have found several such examples. We have also serendipitously found quasars with abnormal, very UV-steep extinction curves as well as a large number of broad absorption line quasars (BALs). The latter allow us to study the dependence of the BAL QSO population on redshift, reddening and luminosity. The results show a strong evolution of the BAL QSO fraction with cosmic time, with a peak at z~2.5 where several quantities in the Universe are also found to peak or vary. In addition,the dependence of this fraction with reddening and luminosity provides new constraints on the models for broad absorption origin in quasars. We are currently carrying out a pilot study of a search for even redder quasars selected from a combination of SDSS, UKIDSS and WISE photometry with the aim of selecting very dust-obscurred quasars or high-redshift BALs at z>2. Preliminary results from the first run et the NOT in March 2015 of the brightest candidates show very promising results which will also be briefly shown in the talk.