Astronomy & Astrophysics Seminar

Zoom: https://tau-ac-il.zoom.us/j/85031132958?pwd=UXZNS05ST01KVXhGTTdLRU9WekZEdz09

A Systematic Search for Techno-signatures using Machine Learning

Snir Pardo, TAU

Abstract:

The Breakthrough Listen Initiative has observed hundreds of nearby stars in search for signs of an extraterrestrial technological civilization. Their public archive includes hundreds of terabytes of radio data to sift through, with the main false-positives being human electronic communication and unintentional electromagnetic emission. I will present our search pipeline which relies on a few simple steps, including using the Uniform Manifold Approximation and Projection (UMAP) algorithm to reduce the dimensionality of the dataset. This and other simplifying assumptions allow us to process the entire sample of about 1300 stars in a reasonable amount of computing time, still about 60 months of CPU time. We generate tens of the most promising candidates that we then rule out by manual inspection. I will present the method, our results, and our prospects for improving the search further.

An Improved Method for Modeling Spectra of Light Echoes

Roee Partoush, TAU

Abstract:

Light echoes give us a unique perspective on the nature of supernovae and non-terminal stellar explosions. Spectroscopy of light echoes can reveal details on the kinematics of the ejecta, probe its asymmetry, and reveal details on its interaction with circumstellar matter, thus expanding our understanding of these transient events. However, the spectral features arise from a complex interplay between the source photons, the reflecting dust properties, and our instrumental setup.In this work I will present an improved method for modeling these effects on light echo spectra, one that relaxes the simplifying assumption of a light curve weighted sum, and instead estimates the relative contribution from each phase. I will discuss our logic, the gains we obtain over the method(s) used in the past, and prospects for further improvements. I will then show how it improves our analysis of echoes from Tycho's supernova.
 

Seminar Organizer: Dr. Iair Arcavi