JPL Home NASA Home Caltech Home
Follow this link to skip to the main content
NASA Logo - Jet Propulsion Laboratory
JPL Home Earth Solar System Stars & Galaxies Technology
Science Visitor and Colloquium Program
Information for Visiting Speakers
Astrophysics Luncheon Seminar

Probing the Small-scale Structure in Strongly Lensed Systems via Transdimensional Inference
Presented by Tansu Daylan
Massachusetts Institute of Technology

Monday, March 4, 2019
12:00 noon in 183-328

Strong lensing is a sensitive probe of the small-scale density fluctuations in the Universe. We implement a pipeline to model strongly lensed systems using probabilistic cataloging, which is a transdimensional, hierarchical, and Bayesian framework to sample from a metamodel (i.e., union of models with different dimensionality) consistent with observed photon count maps. Probabilistic cataloging allows one to robustly characterize modeling covariances within and across lens models with different numbers of subhalos. Unlike traditional cataloging of subhalos, it does not require model subhalos to improve the goodness of fit above the detection threshold. Instead, it allows the exploitation of all information contained in the photon count maps for instance, when constraining the subhalo mass function. We further show that, by not including these small subhalos in the lens model, fixed-dimensional inference methods can significantly mismodel the data. Using a simulated Hubble Space Telescope data set, we show that the subhalo mass function can be probed even when many subhalos in the sample catalogs are individually below the detection threshold and would be absent in a traditional catalog.

JPL Contact: Vanessa Bailey (4-2034)

About the Speaker
Tansu Daylan is a graduate student at MIT.

SVCP Astrophysics

Privacy / Copyrights
  NASA Home Page
Site Manager:

CL 08-3220