When: Wednesday, November 2, 2022, 3:30 PM - 5:00 PMWhere: Physics (G. O. Jones building) Room 516 & online
Speaker: Charles Dalang (QMUL)
Extracting cosmological information from observables is a daunting task. In particular, the peculiar velocity of the observer affects in a systematic way, a large set of observables, including redshift, time intervals, angles, solid angles and specific intensities. In the first part of my talk, I will give an overview of what has led to a confident measurement of the observer’s peculiar velocity, when it really is an expectation, which can and should be tested. In a second part, I shall describe an alternative measurement of the observer’s peculiar velocity with quasar number counts, which gives a discrepant answer. I will provide a potential solution, with different crosschecks that can be performed. Finally, if time permits, I will describe an application to time delay cosmography.