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|Thu, Oct 03|
New York University
"The Future of the Sloan Digital Sky Survey"
I describe plans for the next-generation Sloan Digital Sky Survey, to begin in July 2014, and which consists of three programs, APOGEE-2, MaNGA and eBOSS. APOGEE-2 will use both the Sloan Foundation Telescope at Apache Point and the du Pont Telescope at Las Campanas to study Galactic archaeology with high-resolution near-infrared spectroscopy. MaNGA will develop fiber bundle technology for the BOSS spectrograph to perform multiplexed spatially resolved spectroscopy with an unprecedented combination of wavelength coverage and resolution for 10,000 nearby galaxies. eBOSS will study the Universe’s expansion using a massive survey of galaxies and quasars. eBOSS will also perform follow-up spectroscopy on X-ray and variable sources, making it both the largest and most broadly selected quasar survey. I will show how this innovative set of programs will lead to a better understanding of cosmology and galaxy formation, as well as stellar and exoplanetary astronomy.
|Thu, Oct 10|
University of Washington
" Forecasting Neutron Star Temperatures"
A subclass of neutron stars called quasi-persistent sources accrete matter from a companion episodically. After a bout of intense accretion, x-ray observations indicate that the neutron star surface cools on a time scale of several hundred days. I will review theoretical developments that have helped interpret these observations as thermal relaxation of a hot neutron star crust. Novel nuclear reactions and the properties of matter that is simultaneously solid and superfluid play a role. Although some questions remain, by fitting light curves of several sources, I show that the future thermal evolution of a neutron star that is currently cooling post accretion can be predicted and tested. As we develop more confidence in these cooling models, they can be used to obtain new insights about properties of matter at extreme density (10^10 -10^14 g/cm^3) and relatively low temperature.
|Thu, Oct 17|
University of Washington
"Influence of melting and radioactivity on the thermal and magnetic histories of Earth and Venus
|Thu, Oct 24|
|Michael DiPompeo II|
University of Wyoming
"The Complex Nature of Broad Absorption Line Quasars"
|Thu, Oct 31|
University of Warwick
"Compact Objects in Compact Binaries: The Extremely Low Mass White Dwarfs"
I will present an observational exploration of the exciting physics that can be enabled by high-speed photometry of extremely low-mass (ELM, < 0.25 Msun) white dwarf (WD) stars. WDs bearing such low mass cannot be formed in isolation within a Hubble time, and are necessarily the product of enhanced mass loss from a close binary companion. These ELM WDs are thus found in some of the most compact detached binaries known, many of which are rapidly merging. In fact, we have made the cleanest indirect detection of gravitational waves at visible wavelengths by measuring the orbital decay of a detached, eclipsing 12.75-min WD+WD binary. We have also used photometry to put constraints on fundamental parameters for these rare ELM WDs, many of which are companions to millisecond pulsars. We have discovered the first five pulsating ELM WDs, which will allow us to probe their interiors and confirm that these low-mass WDs have helium cores, as predicted by theory. We have also put initial constraints on the mass-radius relationship for ELM WDs using ellipsoidal variations of the first eight tidally distorted WDs ever found.
|Thu, Nov 07|
University of California, Los Angeles
"First Light with ALMA"
|Thu, Nov 21|
University of Toronto
"Galaxy Kinematics through Integral Field Spectroscopy"
|Thu, Dec 05|
"G2 as a Probe of Sgr A*’s Hot Environs: A View from Chandra and VLA"
The recent discovery of a dense, cold cloud (dubbed "G2") approaching the SMBH at our Galactic Center offers an unprecedented opportunity to test models of black hole accretion and its associated feedback. G2's orbit is eccentric and the cloud already shows signs of tidal disruption by the black hole. High-energy emission from the Sgr A*/G2 encounter will likely rise toward pericenter (mid-to-late 2013, or early 2014) and continue over the next several years as the material circularizes. This encounter is also likely to enhance Sgr A*'s flare activity across the electromagnetic spectrum. We present preliminary results from our 2013 joint Chandra/VLA monitoring campaigns (>400 ks from Chandra and ~30 hours from VLA). Our programs aim to study the radiation properties of Sgr A* as G2 breaks up and feeds the accretion flow, to constrain the rates and emission mechanisms of faint X-ray flares, and to detect G2 itself as it is shocked and heated. Meanwhile, the appearance of a new magnetar (SGR J174540.2-290029, 2.4 arcsec from Sgr A*) and an outburst from a transient LMXB (CXO J174540.0-290005) are yielding additional exciting science. We discuss the constraints these data place on theoretical models for the Sgr A*/G2 encounter and outline plans for continued monitoring with Chandra, XMM, HST, and VLA in 2014.