I will present Beyond The Peak: a FTS spectral mapping survey of ionized, neutral and molecular gas of 22 nearby SINGS galaxies. These observations spatially resolve line emission from [NII], [CI] and 12CO from J(4-3) to J(13-12). A key project goal is to develop diagnostics and an understanding of molecular excitation. This can impact the relation between ground based observations of 12CO and mass density, driving deviations from established empirical relations, like KS, by up to an order of magnitude in different environments. These data provide observational diagnostics of how CO excitation varies inside and between galaxies, and how to use ancillary data needed to correctly interpret low-J observations without mid-J and high-J 12CO transitions.

Surveys now show that a significant fraction (approximately one quarter) of early-type galaxies have molecular gas, detected via CO. The molecular gas in early-types is found to be in very central distributions, where the effects of shear, hydrostatic pressure and possible AGN influence will be maximal. But little is yet known about the state of molecular gas in these galaxies. I will present the results of a survey of 18 molecular-gas rich early-type galaxies from the Atlas3d sample in 12CO, 13CO, HCN and HCO+ from the IRAM 30m telescope. This study reveals a wide range of average optical depths for the molecular gas, but a fairly constant dense gas fraction. We also currently know little about the origin of the molecular gas in these systems, but the molecular gas kinematics indicate that accretion from external sources plays an important role. Additionally, I will discuss whether the molecular gas in early-type galaxies may be less efficient at forming stars, despite the universal molecular gas-SFR relation observed for other galaxy types.

Abstract: One of the best-motivated classes of dark-matter candidate is the Weakly-Interacting Massive Particle (WIMP).  In this talk, I will discuss WIMPs in the context of direct-detection experiments.  First, I will discuss a new signal for WIMP dark matter: gravitational focusing in direct-detection experiments.  This effect leads to an energy-dependent phase-shift in the peak direct-detection event rate throughout the year.  I will discuss this in light of current putative annual-modulation claims.  Second, I will discuss what we can learn about WIMPs in the "early-discovery" days once WIMPs are conclusively found in direct-detection experiments.  I will show that what we can learn about WIMPs depends sensitively on the ensemble of experiments that are running at the time of discovery.

Cosmic Microwave Background (CMB) is a vestige radiation generated during the Recombination era, some 390,000 years after the Big Bang, when the Universe had become transparent for the first time. Initial observations of CMB made by the Wilkinson Microwave Anisotropy Probe (WMAP) led to determining the age of the Universe. The mechanisms that drove the recombination have been discovered by using modeling of the primordial plasma and seeking agreement with the observations. The new Plank Surveyor Instrument launched in 2009 has been expected to produce data about the recombination era of an unprecedented accuracy, that require including better information regarding the basic atomic physics processes into the present models. In this talk, I will review the results for various Rydberg atom - charge particle collisions and establish their relative importance during the stages of recombination era, with respect to each other and to radiative processes. Energy changing and angular momentum changing collisions with electrons and ions are considered.

The remarkable progress of large-scale astronomical surveys in the last two decades have allowed us to constrain the current cosmological model to an unprecedented precision.  At the same time, the field of computational cosmology has emerged, and evolved hand-in-hand with the observational cosmology.   In this talk, I will review the history and current status of observational cosmology, and describe how supercomputers have helped to shape our current views of cosmological structure formation.  In the field of computational cosmology, I argue that we are now entering the third revolution in the cosmological study of galaxy formation. In the latter part of my talk, I will also discuss a separate work on the accretion onto supermassive black holes, and its cosmological importance.

The circumgalactic medium contains signatures of key processes in galaxy formation, such as gas accretion and outflow, and may account for the majority of baryons in the Universe. To probe gas in this environment, I developed new methods to model quasar spectra and measure absorption induced by gas in galaxy halos. Applying the new tools to all quasar spectra in the SDSS, I have compiled a metal absorber catalog of ~50,000 systems and, for the first time, measured the large-scale distribution of gas from galaxies out to ~20 Mpc, linking the gas properties of individual galaxies to their large-scale environment. I will further discuss the new constraints of these results bring to the physics of circumgalactic medium and its role in galaxy formation and evolution in general.

The variety of observations of Active Galactic Nuclei (AGN) show that the nuclear activity is powered by a central massive black hole that drives radio emitting jets and ionizes surrounding line-emitting clouds. This central engine is surrounded by an obscuring torus, comprised of optically thick dusty clouds in a rotating configuration. As a result, sources viewed pole-on have a direct sight-line to the central engine and their spectra show broad lines (~ 10,000 km/sec) that are missing from AGN observed edge-on.  Viewing angle was generally considered the only property controlling the AGN line spectrum. Instead, I will present evidence that line emission is actually evolving as the accretion rate to the central black-hole is decreasing and show that this evolution is explained naturally by the dynamical properties of the toroidal obscuration.

If the baryonic content of galaxies consists primarily of stars, ISM,  and hot (10^7 K) x-ray halo gas, then galaxies are missing between 70 - 95 % of their baryons relative to the cosmological fraction. When accounting for the baryon budget of galaxies, however,  we must not overlook the cooler (10^4 K) photo-ionized gas phase that makes up the circumgalactic medium (CGM). Our collaboration, COS-Halos, has been working to characterize the elusive multiphase CGM that extends out to at least 300 kpc from stellar components of galaxies. Specifically, we have observed the halo gas of 50  galaxies drawn from the imaging dataset of the Sloan Digital Sky Survey (SDSS) whose angular offsets from quasar sightlines and redshifts imply impact parameters (rho < 150 kpc) well inside their virial radii.  As we have shown in previous empirical studies, these data comprise a carefully-selected statistically-sampled map of the physical state and metallicity of the CGM for L ~ L* galaxies. Of particular relevance to the halo missing baryon problem is the total baryonic mass contained in the multiphase CGM, as traced by absorption from hydrogen and metal lines in various ionization states (e.g. MgII, SiII, CII, SiIII, CIII, SiIV, OVI).  In this talk, I will describe how I have modeled the photoionized gas of the CGM with a range of physical conditions, and rigorously determined the CGM gas ionization parameters and metallicities along 33 of the COS-Halos sightlines that provide the best-determined measurements of HI and metal-line column densities.  With the constraints imposed by the data and models, I am able to provide the most reliable mass estimate of the CGM to date, and show definitively that the CGM is an important reservoir of baryons on galactic scales.