Searches for Fast Radio Bursts

Following the discovery of fast radio bursts (FRBs) in 2007, astronomers have entered a new era in astronomy in which understanding the nature of these type of radio transients is one of the most important modern astronomy questions. In this thesis I detail our current state of knowledge in this rapidly evolving field and describe real-time search systems designed to find FRBs using the 20-meter radio telescope at the Green Bank Observatory and the Arecibo L-band Feed Array (ALFA) receiver of the Arecibo 300-meter telescope in Puerto Rico. These experiments are called GBTrans and ALFABURST, respectively. I give details of the observing systems and report on the non-detection of FRBs for both surveys. GBTrans is sensitive enough to detect approximately half of all currently known FRBs while ALFABURST is sensitive enough to detect almost all of the current FRB population. I estimate that GBTrans survey probed redshifts out to about 0.3 corresponding to an effective survey volume of around 124,000 Mpc3. Assuming a constant density for sources per unit co-moving volume and considering the possibility of detecting bright FRBs in the sidelobes of the ALFA beams, I estimate ALFABURST probed redshifts out to about 3.5. Based on this, the expected event rate would be at most two FRBs per year at the 99% confidence level. Modeling the FRB rate as a function of fluence, F, as a power law with Fα, I constrain the index α \u3c 2.5 at the 90% confidence level based on the GBTrans results. A number of pulses from previously known pulsars were detected in both the GBTrans and ALFABURST surveys which provided excellent verification on the survey sensitivity used to compute the effective volumes quoted above. One Galactic transient, J1845+00, was found in the ALFABURST survey. This is most likely a member of the rotating radio transient (RRAT) population. It has so far not been seen in follow-up observations. Eight further single-pulse candidates from ALFABURST are also reported. At the time of writing, due to incomplete metadata records, the positions of these sources are not well enough known to allow further follow-up. Future observations with ALFABURST are anticipated in the coming year. Finally, I also describe preliminary observations from an Arecibo survey of gamma-ray burst sources

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy