BOSS DR12 survey: Clustering of galaxies and Dark Matter Haloes
Sergio Rodriguez, UAM, Madrid and Cal. Berkeley
BOSS SDSS-III is the largest redshift survey for the large scale structure and a powerful sample for the study of the low redshift Baryonic Acoustic Oscillations. We combine the features of the survey, such as, geometry, angular incompleteness and stellar mass incompleteness, with the BigMultiDark cosmological simulation to do a study of the distribution of galaxies in the dark matter halos. Using this large N-Body simulation and the halo abundance matching technique, we found a remarkably good agreement with the 2-point and 3-point statistics of the data.
On the Edge: Exoplanets with Orbital Periods Shorter Than a Peter Jackson Movie
Brian Jackson, Boise State Univeristy
From wispy gas giants to tiny rocky bodies, exoplanets with orbital periods of several days and less challenge theories of planet formation and evolution. Recent searches have found small rocky planets with orbits reaching almost down to their host stars’ surfaces, including an iron-rich Mars-sized body with an orbital period of only four hours. So close to their host stars that some of them are actively disintegrating, these objects’ origins remain unclear, and even formation models that allow significant migration have trouble accounting for their very short periods. Some are members of multi-planet system and may have been driven inward via secular excitation and tidal damping by their sibling planets. Others may be the fossil cores of former gas giants whose atmospheres were stripped by tides.
In this presentation, I’ll discuss the work of our Short-Period Planets Group (SuPerPiG), focused on finding and understanding this surprising new class of exoplanets. We are sifting data from the reincarnated Kepler Mission, K2, to search for additional short-period planets and have found several new candidates. We are also modeling the tidal decay and disruption of close-in gaseous planets to determine how we could identify their remnants, and preliminary results suggest the cores have a distinctive mass-period relationship that may be apparent in the observed population. Whatever their origins, short-period planets are particularly amenable to discovery and detailed follow-up by ongoing and future surveys, including the TESS mission.
New Tools for Galactic Archaeology from the Milky Way
Gail Zasowski, John Hopkins University
One of the critical components for understanding galaxy evolution is understanding the Milky Way Galaxy itself — its detailed structure and chemodynamical properties, as well as fundamental stellar physics, which we can only study in great detail locally. This field is currently undergoing a dramatic expansion towards the kinds of large-scale statistical analyses long used by the extragalactic and other communities, thanks in part to an enormous influx of data from space- and ground-based surveys. I will describe the Milky Way and Local Group in the context of general galaxy evolution and highlight some recent developments in Galactic astrophysics that take advantage of these big data sets and analysis techniques. In particular, I will focus on two diverse approaches: one to characterize the distribution and dynamics of the carbon-rich, dusty diffuse ISM, and one to map the resolved bulk stellar properties of the inner disk and bulge. The rapid progress in these areas promises to continue, with the arrival of data sets from missions like SDSS, Gaia, LSST, and WFIRST.
Asteroseismology of Red Giants: The Detailed Modeling of Red Giants in Eclipsing Binary Systems
Jean McKeever, NMSU
Asteroseismology is an invaluable tool that allows one to peer into the inside of a star and know its fundamental stellar properties with relative ease. There has been much exploration of solar-like oscillations within red giants with recent advances in technology, leading to new innovations in observing. The Kepler mission, with its 4-year observations of a single patch of sky, has opened the floodgates on asteroseismic studies. Binary star systems are also an invaluable tool for their ability to provide independent constraints on fundamental stellar parameters such as mass and radius. The asteroseismic scaling laws link observables in the light curves of stars to the physical parameters in the star, providing a unique tool to study large populations of stars quite easily. In this work we present our 4-year radial velocity observing program to provide accurate dynamical masses for 16 red giants in eclipsing binary systems. From this we find that asteroseismology overestimates the mass and radius of red giants by 15% and 5% respectively. We further attempt to model the pulsations of a few of these stars using stellar evolution and oscillation codes. The goal is to determine which masses are correct and if there is a physical cause for the discrepancy in asteroseismic masses. We find there are many challenges to modeling evolved stars such as red giants and we address a few of the major concerns. These systems are some of the best studied systems to date and further exploration of their asteroseismic mysteries is inevitable.
Characterizing the oscillatory response of the chromosphere during solar flares
Laurel Farris; NMSU Astronomy Department
Quasi-periodic pulsations (QPPs) are observed in the emission of solar flares over a wide range of wavelengths,
particularly in the radio and hard x-ray regimes where non-thermal emission dominates. These pulsations are
considered to be an intrinsic feature of flares, yet the exact mechanism that triggers them remains unclear.
There have been reports of an increase in the oscillatory power at 3-minute periods (the local acoustic
cutoff frequency) in the solar chromosphere associated with flaring events. I propose to investigate the
chromospheric response to flares by inspecting the spatial and temporal onset and evolution of the 3-minute
oscillatory power, along with any QPP patterns that may appear in chromospheric emission. The analysis
will be extended to multiple flares, and will include time before, during, and after the main event. To test
initial methods, the target of interest was the well-studied 2011 February 15 X-class flare. Data from two
instruments on board the Solar Dynamics Observatory (SDO) were used in the preliminary study, including
continuum images from the Helioseismic and Magnetic Imager (HMI) and UV images at 1600 and 1700
Angstroms from the Atmospheric Imaging Assembly (AIA). Later, spectroscopic data from the Interface
Region Imaging Spectrometer (IRIS) will be used to examine velocity patterns in addition to intensity.