Gravitational wave data analysis for the advanced detector era

Resumen

Gravitational wave astronomy became a reality on September 2015 with the LIGO-Virgo discovery of a distant and massive binary black hole coalescence. The more recent discovery of a binary neutron star merger in August 2017, followed by a gamma ray burst and a kilonova, reinforces the expectation of observing the first almost monochromatic continuous gravitational wave; these type signals are suppose to be emitted by spinning non-axisymmetric compact objects e.g neutron stars. This thesis is devoted to the search of gravitational wave emissions from isolated compact objects in our own galaxy. However, even after considering their relative proximity compared to the compact binary mergers we have observed to date, these gravitational-wave are very elusive as their strain amplitudes are orders of magnitude weaker i.e. O(10) compared to the typical O(10) observed from compact binary mergers. Due to this the detection of such weak signals would be the result of long time spans integration of data, this problem translates in a threshold sensitivity and parameter space volume due to limited computational resources. The main work has focused on the development and optimization of semi-coherent methods, based on the Hough transform, to search for continuous sinusoidal gravitational wave signals from unknown continuous sources e.g neutron stars that do not beam a radio signal in the earth’s direction and for signals of intermediate durations (of the order of hours to days) as applied in the GW170817 post-merger remnant search for a newborn neutron star. The work I present here has been crucial for a number of continuous wave searches in data from the advanced LIGO detectors, which are collected in this thesis. My contributions have been included in three LIGO-Virgo full collaboration papers in which I had a leading role, as well as in several short author papers. I have also been involved in multiple updates of the LSC Data Analysis Software (LIGO Algorithm Library - LALSuite), including a new full search for transient gravitational waves of intermediate duration.