Recent Talks

The anomalous microwave emission (AME) is an additional diffuse foreground component, originated by an emission mechanism in the ISM different from the well-known synchrotron, free-free and thermal dust emissions. It was first discovered at the end of the nineties as a correlated signal between microwave CMB maps and infrared maps tracing the dust emission. Ever since several detections have been found in individual clouds in our Galaxy. This emission is an important contaminant for current and future CMB experiments, and therefore its characterization (both in temperature and in polarization) and understanding is mandatory. So far different theoretical models have been proposed to explain the physical mechanism that give rise to this emission. In this talk we will review these models and will present the current observational status of the AME, with particular emphasis on some recent studies that have been performed by our group in the IAC in the Perseus molecular complex and in the Pleiades reflection nebula.

The success of the next generation of instruments for 8 to 40-m class telescopes will depend on the ability of Adaptive Optics (AO) systems to provide excellent image quality and stability. This will be achieved by increasing the sampling, wavelength range and correction quality of the wave front error in both spatial and time domains. The modern generation of AO wavefront sensor detectors started in the late nineties with the development of the CCD50 detector by e2v under ESO contract for the ESO NAOS AO system. With a 128x128 pixels format, this 8 outputs CCD runs at a 500 Hz frame rate with a readout noise of 7e-. A major breakthrough has been achieved with the recent development of the CCD220, also by e2v technologies. This 240x240 pixels 8 outputs EMCCD (CCD with internal multiplication) has been jointly funded by ESO and Europe under the FP6 programme. The CCD220 detector and the OCAM2 camera are now the most sensitive system in the world for advanced adaptive optics systems, offering an astonishing <0.2 e readout noise at a frame rate of 1500 Hz with negligible dark current. Extremely easy to operate, OCAM2 only needs a 24 V power supply and a modest water cooling circuit. This system will be extensively described in this talk. An upgrade of OCAM2 is foreseen to boost its frame rate to 2500 Hz, opening the window of XAO wavefront sensing for the ELT. Since this major success, new developments started in Europe. One is fully dedicated to Laser Guide Star AO for the ELT with an ESO involvment. The spot elongation from a LGS SH wavefront sensor induces an increase of the pixel format. Two detectors are currently developed by e2v. The NGSD will be a 672x672 pixels CMOS detector with a readout noise of 4e (goal 1e) at 700 Hz frame rate. The LGSD is a scaling of the NGSD with 1680x1680 pixels and 3 e readout noise (goal 1e) at 700 Hz frame rate. New technologies will be developed for that purpose: new CMOS pixel architecture, CMOS back thinned and back illuminated device, full digital outputs. In addition, the CMOS technology is extremely robust in a telescope environment. Both detectors will be used on the ELT, depending on the AO system considered. Additional developments also started for wavefront sensing in the infrared based on new breakthrough using ultra low noise Avalanche Photodiode (APD) arrays within the RAPID project. The latter should offer a 320x240 8 outputs 30 microns IR array, sensitive from 0.4 to 3.2 microns, with 2 e readout noise at 1500 Hz frame rate. First results of this project will be showed.

In this talk I will review the subject of cosmological inflation, a period of early accelerated expansion. I will discuss Friedmann-Robertson-Walker cosmology and the horizon and flatness problems, and introduce inflation as a solution to those problems. I will also discuss the generation of  the primordial (scalar and tensor) spectrum of perturbations which provides the seeds for the large scale structure in the Universe. I will review quickly the status of observations in relation to the inflationary parameters, and then the implications for model building.

The spectral analysis of HII regions allows one to determine the chemical composition of the ionized gas phase of the interstellar medium (ISM) from the solar neighborhood to the high-redshift galaxies. Therefore, it stands as an essential tool for our knowledge of the chemical evolution of the Universe. However, it turns out that chemical abundances of heavy-element ions determined from the bright collisionally excited lines (CELs) are systematically lower than the abundances derived from the faint recombination lines (RLs) emitted by the same ions. Today, this controversial issue is known as abundance discrepancy problem and it is far from negligible. In the analysis of Galactic and extragalactic HII regions the O2+/H+ ratio calculated from the OII RLs is between 0.10 and 0.35 dex higher than that obtained from the [OIII] CELs. In this talk, we will face this problem in the benchmark object of the solar vicinity, the Orion Nebula. Due to its high surface brightness and proximity, the Orion Nebula is an ideal lab, which allows us to study in detail the possible role of its rich and well-resolved internal structure (such as Herbig-Haro objects, protoplanetary disks or bars) on the abundance discrepancy.

Relativistic jets in AGN in general, and in blazars in particular, are the most energetic and among the most powerful astrophysical objects known so far. Their relativistic nature provides them the ability to emit profusely in all spectral ranges from radio wavelengths to gamma-rays, as well as abrupt variability in all time scales (from hours to years). Since the birth of gamma-ray astronomy, locating the origin of gamma-ray emission has been a fundamental problem for the knowledge of the emission processes involved. Deep and densely time sampled monitoring programs with the Fermi Gamma-ray Space Telescope and several other facilities at most of the available spectral ranges (including polarization measurements where possible) are starting to shed light for the case of blazars. After a short review of the status of the problem, some of the latest results locating the GeV emission in the jets of some blazars, at >10 parsec from the central AGN engine, will be presented together with their implications about the gamma-ray emission mechanisms involved

In the last few years there has been cumulative evidence showing that massive galaxies have dramatically grown in size since z~3. This result has remained very controversial as it seems at odd with our previous knowledge based on the detailed analysis of the stellar populations of nearby massive spheroids which shows that their stars were form very early on and over a short time interval. In addition to this, there is growing observational support for a significant evolution of the morphologies of these galaxies with cosmic time. In this talk, I will summarize what we have learned since the discovery of the strong evolution of the morphological properties of the massive galaxies, the mechanisms proposed to explain their origin and size increase, and the pending questions still to solve.