Galactic dynamo theory reproduces basic features of magnetic fields in nearby disk galaxies. The formation and ordering of magnetic fields depend on such parameters as the ratio of the disk thickness to the radius of the galaxy, its angular velocity and turbulence of the gas. We consider the mean-field dynamo mechanism to trace the evolution of magnetic fields in normal and starburst galaxies down to the disk formation epoch (z~1.5) and beyond it. The mean-field dynamo is able to increase the strength of a large-scale magnetic field for about 1000 times (~10-9 to ~10-6 Gauss) in ~6x109 years. At earlier epochs (z~3) the turbulent dynamo is envoked to provide a generation of magnetic fields in protogalaxies from 10-22 to 10-9 Gauss in a relatively short time period of 4x108 years. We discuss different evolutionary tracks for normal and starburst galaxies and perspectives to test them with future radio telescopes such as LOFAR and SKA.

In this poster we present ongoing efforts to tackle the problem of where massive star formation takes place within galaxies as a function of epoch. We present the techniques we are developing in order to analyze quantitatively the distribution of star formation within galaxies, and apply them to both local objects and those at increasing redshift. The parameters quantified include the radial concentration, the azimuthal asymmetry and the clumpiness on large and small scales, as well other morphological parameters we define and use for the first time. All the parameters have been calibrated on a local sample of galaxies using our own Hα images and comparing them with the same parameters measured on images from GALEX and SDSS. We then use them to analyze images from the HST GOODS survey over a range of redshift up to z~1.

Despite the fact that the recent years have seen the construction of large samples of distant disk galaxies, there is still debate on the evolution of fundamental scaling relations like the Tully-Fisher Relation (TFR), which links the luminosity and maximum rotation velocity. Different studies have found different results ranging from a non-evolving TFR to strong changes both in its slope and zero point. Our analysis relies on a data set of ~200 disks at 0.1

A key question in the formation and evolution of galaxies is the epoch and mechanisms of mass assembly. We will present the first results of an on-going ESO Large Program, using the AO-assisted NIR 3D spectrograph SINFONI on VLT, aiming to measure the velocity field of a unique sample of ~140 star-forming galaxies in the redshift range 1.0-1.8 selected in the VIMOS VLT Deep Survey. This large sample, spanning a wide range of masses (logM=[9-12]), is statistically representative of the overall population and thus suitable to probe the evolution in masses, mass-to-light ratios, and metallicities of these galaxies, as well as the fraction of mass assembled by merging, in the few billion years when star formation is at his maximum.

The gas content of galaxies is crucial for their evolution. Its connection with the excess of star formation at intermediate redshift and its dependence on the global and local environment of galaxies is being explored with ultra deep HI observations with the WSRT at z=0.2. The targeted volumes include two galaxy clusters, known to be very different in their dynamical state and star formation properties, as well as the large scale structure that surrounds them. Of particular interest is the gas content of the blue galaxies in the center of the massive Butcher-Oemler cluster A963 at z=0.206, in relation to the gas content of the blue galaxies in the surrounding field. On this poster, we present the first results from our ongoing HI survey at z=0.2.

In recent years, there has been a very hot debate on the nature and possible evolutionary paths of the faint, blue galaxies found in deep images of the sky. The bluest, high surface brightness objects found in these images are named Luminous Compact Blue Galaxies, and several possible evolutionary paths have been suggested for these galaxies. One path is that these systems are the proto-nuclei of spiral galaxies, still in their formation process. The other path proposes that these systems are the progenitors of today's population of spheroidal and dwarf elliptical systems. The poster presents and discusses evidence for and against these two evolutionay paths.

We have explored the galaxy disk/extended halo gas kinematic relationship using rotation curves (Keck/ESI) of ten intermediate redshift galaxies which were selected by MgII halo gas absorption observed in quasar spectra (Keck/HIRES, VLT/UVES). The halo gas is sampled at projected galactocentric distances of 25-105 kpc and at a range of position angles with respect to the galaxy major axis. Previous results of six edge-on galaxies, probed along their major axis, suggest that observed halo gas velocities are consistent with the galaxy disk angular momentum; implying extended disk-like halo rotation at galactocentric distances of 25-72 kpc. Using our new sample of ten galaxies, we demonstrate that the gas velocities are by and large not consistent with being directly coupled to the galaxy kinematics. Our sample contains two pairs of interacting galaxies and in one case, the gas velocities are both retrograde to the disk rotations and the angular momentum of the system. Thus, mechanisms other than co-rotation dynamics (i.e., gas inflow, feedback, galaxy-galaxy interactions, etc.) must be invoked to account for the overall observed kinematics of the halo gas. In order to better understand the dynamic interaction of the galaxy/halo/cosmic web environment, we performed similar mock observations of galaxies and gaseous halos in Lambda-CDM cosmological N-body simulations, with resolutions of 20-50 parsecs. Physical processes influencing halo gas dynamics, such as radiative cooling, star formation, metal enrichment, and thermal feedback due to supernovae, are implemented in the code. We present an example case of a z=0.85 galaxy with various orientations probing halo gas at a range of positions. The gas dynamics inferred using simulated quasar absorption lines are also inconsistent with observational data. Our results suggest that the galactic inflow and outflow mechanisms currently implemented in cosmological models are not yet fully understood.

Size is a fundamental parameter in our understanding of galaxy formation. The first galaxies- small, low mass disks grow to the large, structured galaxies of the present day through repeated mergers. Observations of large, massive disk galaxies at redshifts between 1.5 and 3 pose an interesting challenge to the hierarchical picture. The FIRES survey (Labbe et al. 2003) reveals that these galaxies have sizes comparable to the Milky Way. How did mass assemble into such large galaxies only 2-3 Gyr after the Big Bang? In this project, we aim to characterize the dynamical state of these large disks. Here, we present our preliminary results- the fraction of these galaxies undergoing star formation with near infrared spectroscopy obtained using the 8-m Gemini South Telescope.

Luminous Infrared Galaxies (LIRGs) are characterized by strong thermal emission in the IR from dust heating within both starbursts and AGN. In the nearby universe, major mergers, which drive star formation and AGN activity, create the majority of LIRGs. In contrast, half of all LIRGs at intermediate redshift (z~0.7) are normal looking spirals indicating that major mergers were not necessary to form LIRGs in the past. As part of the Center for Adaptive Optics Treasury Survey (CATS) we obtained high spatial resolution K-band imaging of 14 intermediate redshift LIRGs in the GOODS-S field. The observations were made with the Keck Laser Guide Star Adaptive Optics facility. We combine the HST optical images from GOODS with the Keck near-IR images to study the spatial distribution of stellar populations within the LIRGs. For each system, we attempt to identify the sites of recent star formation. Was the star formation centrally concentrated, possibly triggered by a minor merger or bar instability? Was it smoothly distributed throughout the galaxy, indicating a more regulated process? Or, was the star formation preferentially on the outskirts suggesting inside-out disk growth? We compare the stellar population distributions of the LIRG systems to a sample of “normal” disk galaxies drawn from the same fields.

Luminous Compact Blue Galaxies (LCBGs) are common at z~1, contributing 45% of the total star formation rate density at that time. By z=0, they are a factor of ten rarer and provide a negligible contribution to the local star formation rate density. While we know that LCBGs are rapidly evolving, we do not know what drives their evolution or into what type of galaxy they evolve. We present HI observations of a sample of local analogs to the high-redshift LCBGs. These data provide us with a measure of the fuel for future star formation and the total masses of LCBGs; information that we cannot currently obtain for z~1 LCBGs. In concert with a multi-wavelength dataset, we attempt to constrain what the LCBGs were at z~1 and into what they have evolved.

We present spatially resolved (<0.1") spectra of Hα emission from six high-redshift (z~1.5) star forming galaxies. These observations were obtained at Keck Observatory using the integral field spectrograph OSIRIS and the laser guide star adaptive optics (LGS AO) system. OSIRIS coupled with LGS-AO is able to measure a full two-dimensional mapping of Hα morphology and dynamics of galaxies at sub-kiloparsec scales. This study is aimed at identifying and analyzing rotationally supported objects in the early universe at a look back time (~9.3 Gyr) close to the estimated age of the Milky Way disk. We will discuss Hα kinematics, disk modelling, merger scenarios, mass distributions, star formation rates, and metallicity for each galaxy. In addition, we will address the implications for galaxy formation with respect to our sample and other complementary studies at higher redshifts.

For young galaxies, or galaxies with ongoing star formation, a substantial fraction of the rest-frame ultraviolet to near-IR light comes from the ionized interstellar medium in the form of emission lines and nebular continuum. At high redshifts, stellar populations are on average younger and the star formation activity higher than in the local Universe. Both of these effects act to boost the impact of nebular emission on the overall spectrum, yet the colours of high-redshift galaxies are routinely analyzed assuming that the observed optical to mid-infrared light is directly produced by stars. Here, we highlight the problems with this approach and assess the impact of nebular emission on UBVRIJHK and Spitzer IRAC/MIPS broadband photometry as a function of redshift for galaxies with different star formation histories.