Mercury’s proximity to the Sun and its low magnetic field strength lead to dynamic interactions of the solar wind with the magnetosphere as well as with the planet’s surface, which are unique in the solar system. MESSENGER, having been in orbit about Mercury since March 2011, has made important discoveries of this exciting magnetospheric environment. In this talk, I will discuss some aspects of Mercury’s magnetosphere, paying special attention to the bow shock, magnetopause, and cusp regions as well as to the planet’s internal magnetic field. I will discuss how we characterized the time-averaged shape and location of Mercury’s magnetopause and bow shock, as well as established these boundaries’ responses to the solar wind and interplanetary magnetic field. I will also describe the first observations of Mercury’s northern cusp region using Magnetometer data, and our estimates of the flux of precipitating particles to the surface. Finally, I will discuss a novel adaptation of the electron reflectometry technique in which we use protons precipitating to the surface (observed by the Fast Imaging Plasma Spectrometer onboard MESSENGER) to acquire the first measurements of Mercury’s surface magnetic field strength.

Most galaxies in the Universe host low-luminosity AGNs. These systems exhibit a vast range of dynamical and radiative effects, which require high sensitivity and high angular resolution to study. The closest objects with the largest central supermassive black holes are revealing their secrets with the improvement of instrumentation. I will review recent progress on observing with Chandra and modeling of the accretion flow onset regions in Sgr A* and NGC3115. The hot accretion flow in these sources is shaped by the combined effects of (1) radius-dependent mass injection by stellar winds, (2) galactic gravitational potential, (3) small-scale feedback such as conduction, and (4) supernova feedback. The natural outcomes of modeling are the virial/supervirial gas temperature and inhibited accretion with shallow density profile.

The quest for gravitational waves is reaching a key milestone as Advanced LIGO is approaching completion and science runs are scheduled to begin in 2015. In this talk, I will review the status and timelines of second generation gravitational wave detectors and the prospected observing scenarios over the next decade, with focus on searches for gravitational wave transients, the ability to localize gravitational wave sources and the ongoing efforts towards coincident searches of gravitational wave and electromagnetic signatures.

Abstract: 98% of all stars will end their lives as white dwarfs. In old stellar populations, such as globular clusters and stellar halos, the bulk of the progenitor stellar mass function above the present day turnoff is therefore now populated on the white dwarf cooling sequence. These remnants have remarkable properties and can be studied in exquisite detail to reveal their temperatures, gravities, and masses. In this talk, I will describe unprecedented HST imaging and Keck spectroscopic observations of these stars in old stellar populations. This work has led to the first global constraints on the mapping between initial stellar mass and final mass, and therefore has broad applications for understanding stellar evolution theory, mass loss, and chemical enrichment of the interstellar medium. Additionally, through a new technique, I will describe how we can invert the process of stellar evolution to establish a relation between the remnant mass in an old stellar population and the parent age. By applying this technique to nearby Milky Way halo stars, we measure the age of the inner halo of the Milky Way to be 11.4 ± 0.7 Gyr.

The last 180 years of astronomy at the institutions now known as the Five Colleges include: students arriving at college by stage coach; an observatory built as an octagon; a famous poet; an infamous, illicit love affair; pioneering observations from the Chilean desert; early astrobiology; the first SETI, more than 100 years ago; the first astronomical observations from an artificial platform above the earth’s surface; an innovative way to augment department budgets; discrimination against women in astronomy; the Layzer-Irvine equation; the Hapke-Irvine Law; a 100-ft long absorption cell for infrared spectroscopy; telescopes built with telephone poles and chicken wire; a Nobel prize; the Rydbeck factor; the Five College Radio Astronomy Observatory; new interstellar molecules; viruses from space and a new physical/biological measurement unit; a phony press release picked up by the media; giving the International Halley Watch FITS; and, after 800 years, a Scottish coat-of-arms with a comet (Halley’s, of course).

The Hubble Ultra Deep Field in the redshift range z=1 to 5 is dominated by clumpy galaxies, whose kiloparsec-scale star-forming complexes have masses 100x greater than similar complexes in local spirals. The clumps evidently form from gravitational instabilities following gas accretion, and the galaxies transform into the familiar disk morphologies of nearby spirals after a Gyr. Though rare, there are UV-bright local analogs of these distant clumpy galaxies that appear to be at an early evolutionary stage. I will compare star formation properties of local and distant galaxies based on photometry and spectroscopy, and present recent observations of local tadpole galaxies that show evidence for accretion of metal-poor gas.

Most stars, including our Sun, are thought to have formed within a stellar cluster, yet much of the star formation process within this type of environment is poorly constrained. Recent results from the Herschel Space Telescope hint that dense filaments of gas and dust are intimately linked with star formation, for both isolated stars and clustered systems. Several models also predict the importance of filaments in cluster formation, but observations of the key predicted processes are limited. I will present results from a Mopra survey of the Serpens South system which addresses this lack of observations. Serpens South is a recently discovered young cluster forming deeply embedded within a prominent dense filament. As such, it provides an ideal testbed for the scenario of significant mass accretion onto clusters via filaments. I will finish by discussing ways in which numerical simulations of star formation can be used to gain a deeper understanding of the processes involved, highlighting ongoing efforts of the group at McMaster University.

Empirical relations connecting star formation and the interstellar medium form the basis of many theoretical models of galaxy evolution. After reviewing the current observational status (and its limitations) of star formation laws, I will show what role they play for the evolution of various global galaxy properties. Observations of the mass-metallicity relation and of the cosmic star formation history, in particular, put stringent constraints on the actual functional relationship between star formation and the gas reservoir of galaxies. These results point towards a very simple and essentially time-independent star formation law that encapsulates most aspects of star formation relevant for the evolution of average galaxy properties across cosmic history.

Near-Field Cosmology: Big Science From Small Galaxies

The search for extra-solar planets has led to the surprising discovery of many Jupiter-like planets in very close proximity to their host star, the so-called ``hot Jupiters'' (HJs). Even more surprising, many of these HJs have orbits that are eccentric or highly inclined with respect to the equator of the star, and some (about 25%) even orbiting counter to the spin direction of the star. This poses a unique challenge to all planet formation models. We show that secular interactions between Jupiter-like planet and another perturber in the system can easily produce retrograde HJ orbits. We show that in the frame of work of secular hierarchical triple system (the so-called Kozai mechanism) the inner orbit's angular momentum component parallel to the total angular momentum (i.e., the z-component of the inner orbit angular momentum) need not be constant. In fact, it can even change sign, leading to a retrograde orbit. A brief excursion to very high eccentricity during the chaotic evolution of the inner orbit allows planet- star tidal interactions to rapidly circularize that orbit, decoupling the planets and forming a retrograde hot Jupiter. We estimate the relative frequencies of retrograde orbits and counter to the stellar spin orbits using Monte Carlo simulations, and find that the they are consistent with the observations. The high observed incidence of planets orbiting counter to the stellar spin direction may suggest that three body secular interactions are an important part of their dynamical history.

The study of structure formation during the first billion years is advancing rapidly, driven by pathfinding discoveries with the Hubble Space Telescope and motivated by anticipated studies that will wield next-generation facilities including ALMA, JWST, and LOFAR. I will show how detailed comparisons between numerical simulations and observations such as these inform our understanding of galaxy growth well into the cosmic dark ages. I will discuss observational and theoretical arguments that constrain how young galaxies ionized and heated the intergalactic medium. I will describe how the intergalactic medium's structure regulated the progress of cosmological reionization. Finally, I will show how a new class of cosmological radiation hydrodynamic simulations can be used to interpret existing observations of low-ionization metal absorbers that trace the earliest stages of structure formation.

Luminous Infrared Galaxies (LIRGs) are observed primarily to be interacting and merging galaxies. They are the sites of rampant star formation and active galactic nuclei (AGN), which are fed by abundant supplies of molecular gas. However, the very property that led to their initial discovery as a significant population - their high infrared luminosity - also makes them difficult to study; the majority of the UV and optical light from young, massive stars and AGN is absorbed by obscuring dust and re-emitted in the infrared. The Great Observatories All-sky LIRGs Survey thus makes use of the diversity in wavelength coverage of the present space-based telescopes to probe the activity in a large (~ 100 - 200), flux-limited sample of LIRGs from the Revised Bright Galaxy Sample (RBGS). The majority of the talk will be devoted to discussing the survey as a whole. The latter part of the talk will be focussed specifically on a GOALS analysis of NGC 2623.

Interstellar dust radiates most powerfully in the far-infrared, typically peaking in the 100-200um region. However, the emission at longer wavelengths is often unexpectedly strong. This is particularly true at microwave frequencies (~cm wavelengths), where sensitive studies of the CMB revealed emission that was far stronger than expected. This "anomalous microwave emission" is almost certainly produced in part by dust grains (PAHs) spinning at tens of GHz, although other processes may also contribute. The emission at mm- and submm wavelengths has also been problematic. Some galaxies (e.g., the SMC) show much stronger emission near ~1 mm than expected from "normal" dust models. This is sometimes attributed to large masses of very cold dust, but more likely it is telling us about new emission processes. I will argue that much of the submm excess in the SMC may be magnetic dipole emission from iron nanoparticles. If true for the SMC, this may presumably apply to other low-metallicity galaxies as well.

Chandra has revolutionized X-ray astronomy by being a versatile observatory for studying objects ranging in scale from the inner structure of the Crab pulsar nebula to high-redshift AGNs, clusters of galaxies, and cosmology. Chandra is operating well and is expected to last into 2020's. In the next few years, we expect a launch of an array of smaller missions, which will open new areas of X-ray astronomy such as polarimetry, imaging at E>10 keV, sensitive surveys, high-resolution X-ray spectroscopy, ensuring a continues short-term vibrancy of the field. However, in the post-Chandra era, X-ray astronomy cannot be sustained by small-scale experiments, and there are no concrete plans for a powerful, observatory-class mission. What an X-ray observatory for the 2020's can look like? We are developing a concept, SMART-X, for a next-generation X-ray observatory with large-area, 0.5" resolution grazing incidence adjustable X-ray mirrors, high-throuput critical transmission gratings, and X-ray microcalorimeter and CMOS-based imager in the focal plane. High angular resolution is enabled by new technology based on controlling the shape of mirror segments using thin film piezo actuators deposited on the back surface. Science application include observations of growth of supermassive black holes sinse redshifts of ~10, ultra-deep surveys overs 10's of square degrees, galaxy assembly at z=2-3, as well as new opportunities in the high-resolution X-ray spectroscopy and time domain.