| Abstract : | The direct detection of gravitational waves (GW) has opened a new window to the universe and resulted in the emergence of a new field: gravitational waves astronomy. In recent years ground-based interferometric detectors have detected numerous ‘chirp’ signals from various merger events. But there are other types of sources of gravitational waves that are yet to be detected. One of them is the result of accumulation of unresolved short-duration GW signals and events of cosmological origin. This persistent background signal, which is expected to be detected in the coming years, is known as the stochastic gravitational wave background (SGWB). Searching for this kind of source is challenging for its stochastic nature and computational resource requirements, especially for a narrowband SGWB search. With the development and implementation of a new data folding technique along with a new pipeline called PyStoch, many of the computational challenges were resolved. Hence, for the first time a search for narrowband SGWB was performed in all directions of the sky in the sensitive frequency ranges of the LIGO, Virgo interferometers. This is the all sky all frequency (ASAF) search which was done on the data from the first three observing runs of the LIGO Virgo interferometers. Although no evidence of a SGWB was found in the data, the robustness of this pipeline and the underlying method has been demonstrated; which implies this pipeline can be used to detect a SGWB when more sensitive data is obtained in future. Moreover, in this analysis we put upper limits on the GW sky in different directions and different frequencies and also identify a few probable directions of GW sources (currently considered insignificant candidates) which need more follow-up. |
