ELFT HÍRADÓ

[Sandor Katz <katz AT bodri.elte.hu>]

majus 3, 14:15, ELTE-ELFT szeminarium, Lagymanyosi tomb 2.54

Yohai Meiron (Eotvos): Detecting triple systems with gravitational wave 
observations

The Laser Interferometer Gravitational Wave Observatory (LIGO) has recently 
discovered gravitational waves (GWs) emitted by merging black hole binaries. We 
examine whether future GW detections may identify triple companions of merging 
binaries. Such a triple companion causes variations in the GW signal due to the 
varying path length along the line of sight during the orbit around the center 
of mass (Doppler shift). Other effects such as relativistic beaming, 
gravitational redshift, and Shapiro may also distort the waveform. We find that 
the prospects for detecting the triple companion are the highest for low-mass 
compact object binaries which spend the longest time in the LIGO frequency 
band. In particular, for merging neutron star binaries, LIGO may detect a white 
dwarf or M-dwarf perturber at signal to noise ratio of 8, if it is within 0.4 
solar radius distance from the binary and the system is within a distance of 
100 Mpc. Stellar mass (supermassive) black hole perturbers may be detected at a 
factor 5x (1000x) larger separations. Such pertubers in orbit around the 
merging binary emit GWs at frequencies above 1 mHz detectable by the Laser 
Interferometer Space Antenna (LISA) in coincidence.