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Compact Galactic Binaries
Thursday Chair: Steve Eikenberry
08:00 - 08:30 Warren Brown
Smithsonian
White Dwarf BinariesDownload
08:30 - 09:00 Shane Larson
CIERA/Northwestern University
Galactic Ultra-compact Binaries in Gravitational WavesDownload
09:00 - 09:30 Sweta Shah
Radboud University, NIKHEF
Gravitational wave astrophysics of Galactic binariesDownload
White Dwarf Binaries Download
Warren Brown - Smithsonian
White dwarfs provide useful verification binaries because they emit light. White dwarfs are the most common type of stellar remnant in the Galaxy, and nearby detached binaries exist at mHz frequencies. I will describe the experimental constraints provided by optical spectroscopy and photometry. Our targeted survey of extremely low mass white dwarfs, objects that form in compact binaries, has discovered a number of eLISA verification binaries in the last 3 years. I will present our latest Pdot measurements for J0651, and a newly discovered verification binary at 2 mHz.
Galactic Ultra-compact Binaries in Gravitational Waves Download
Shane Larson - CIERA/Northwestern University
The galaxy harbors at least $10^7$ ultra-compact binaries that radiate in the millihertz band covered by space-based gravitational wave detectors. A large fraction of these binaries will have overlapping signals that merge to form a confusion limited foreground, but there will also be a large number (tens of thousands) that are expected to be individually resolvable. Many "verification binaries" from this population have already been seen in electromagnetic telescopes, and will be among the first sources detected by a LISA-like mission. A tremendous amount of progress has been made over the past several years in simulating that population, and determining effective methods for measuring and characterizing these systems in gravitational waves. This talk will discuss the nature of the galactic binary gravitational wave foreground, review how space based detectors like LISA will perceive this important population of stars, explore what is known about the compact binary data analysis problem, and note the science that we hope to pursue through detailed studies of individual binary star systems.
Gravitational wave astrophysics of Galactic binaries Download
Sweta Shah - Radboud University, NIKHEF
Combining gravitational wave (GW) data and electromagnetic (EM) data for the Galactic binaries can be useful in further constraining the sources’ parameters. I will review our recent results where we find that the EM data can significantly improve the determination of the astrophysically interesting parameters of the sources such as amplitude, inclination, masses and distance. We find that inclination of AMCVn*– like systems will not be determined by the GW data whereas it is significantly accurately measured from the EM data. This measurement of inclination reduces the GW uncertainty in the amplitude by a factor of 6. We also find that a prior knowledge of sky position for the binaries will reduce the uncertainties in amplitude and inclination by up to a factor of 2. These factors can go up to 60 if a prior knowledge of inclination is also included. Furthermore we find that EM data on distance and radial velocity of the stellar components significantly improve our knowledge of the individual masses, which depend on the inclination of the source and its signal strength. I also address the feasibility of doing tidal studies of very short period white dwarf binaries with eLISA. *a verification binary source