List of past INPA Seminars — 2018
from a massive stellar envelope based on relativistic hydrodynamical simulations and post- process radiation transfer calculations in three dimensions. It is shown that structures developed within the jet during its propagation have a significant imprint on the resulting emission. Particularly, we show that the viewing angle dependence of the emission properties caused by the lateral structure naturally reproduces the observed correlation between the peak energy and luminosity (Yonetoku relation). We also show that the emission possesses non-negligible degree of polarization.
In the first part of this seminar I will present the DEAP-3600 experiment and its recent results with an emphasis on radioactive backgrounds. In the second part of the seminar I will briefly describe a few recent investigations of rare beta and double beta decay processes such as 36Ar, 39Ar and 42Ar with DEAP but also other isotopes with gamma-spectroscopy setups. I will illustrate their importance in the context of radioactive backgrounds in other low background experiments and in the context of understanding nuclear structure. Especially the better understanding of nuclear models and their intrinsic parameters is needed to obtain more reliable nuclear matrix elements e.g. for neutrinoless double beta decay processes in order to connect the observed half-life to the the effective Majorana neutrino mass.
This discussion will first elaborate on some of the experimental and theoretical niceties of the muon, and briefly look at the particle from a historical perspective, emphasizing a few of the many important roles that its played in piecing together our current understanding of particle physics. We will then look at a variety of anomalies in experiments using muons, which, taken together may suggest the possibility of sensitivity to new physics within reach of future experiments, some of which will also be looked at. Topics include recent developments in the proton radius puzzle, the muon anomalous magnetic moment, hints of lepton flavor non-universality in B decays, and searches for charged lepton flavor violation. For fun, a recent discovery in the Great Pyramid of Giza using muon tomography will also be discussed.
The next generation of cosmological surveys promises significant advancements in the field of weak gravitational lensing. As such, it is crucial that relevant systematic effects such as the intrinsic alignment of galaxies are well-understood. I will discuss a new method for measuring the scale-dependence of the intrinsic alignment contamination to the galaxy-galaxy lensing signal, which takes advantage of multiple shear estimates applied to the same data set. For a galaxy-galaxy lensing measurement which uses LSST sources and DESI lenses, the signal-to-noise on the intrinsic alignment signal measured by our method is forecast to improve on an existing method (Blazek et al. 2012) by a factor of >2, for optimally chosen pairs of shear estimates.
Recent advances in the analysis of the X-ray emission and its variability in AGN, observed by the great X-ray observatories, coupled with general relativistic ray tracing simulations, have revealed vast amounts of information about the extreme environments in the immediate vicinity of the black hole event horizon. The effects of general relativity on the reflected emission can be exploited to pinpoint the location of reflection in the strong gravitational field, while time delays in the X-ray echoes off the accretion disc enable the structure of the innermost regions to be mapped.
We discover how the X-ray emitting corona evolves on long and short timescales, giving rise to orders of magnitude variation in luminosity as well as the processes the corona can undergo during transient events, most notably the collimation and ejection of portions of the corona during X-ray flares, reminiscent of the aborted launching of a jet. The latest X-ray reverberation studies are revealing, for the first time, structure within the corona including a persistent collimated core akin to the base of a jet, even in radio-quiet sources, alongside a second component associated with the accretion disc itself.
This gives us important insight into the small-scale processes close to the event horizon that enable supermassive black holes to power some of the most luminous objects in the Universe, launch vast jets and play their important role in the formation of structure in the Universe.
We use the absorption by neutral Hydrogen and by Magnesium-II observed in quasar spectra to trace the underlying matter density fluctuations. Combined with galaxies and quasars, these two tracers allow to measure the 3d cross-correlation of matter from a redshift of z = 0.5 up to a redshift of z = 2.4.