1 code implementation • 15 Nov 2022 • Ji Won Park, Simon Birrer, Madison Ueland, Miles Cranmer, Adriano Agnello, Sebastian Wagner-Carena, Philip J. Marshall, Aaron Roodman, The LSST Dark Energy Science Collaboration
For each test set of 1, 000 sightlines, the BGNN infers the individual $\kappa$ posteriors, which we combine in a hierarchical Bayesian model to yield constraints on the hyperparameters governing the population.
2 code implementations • 30 Nov 2020 • Ji Won Park, Sebastian Wagner-Carena, Simon Birrer, Philip J. Marshall, Joshua Yao-Yu Lin, Aaron Roodman
The computation time for the entire pipeline -- including the training set generation, BNN training, and $H_0$ inference -- translates to 9 minutes per lens on average for 200 lenses and converges to 6 minutes per lens as the sample size is increased.
1 code implementation • 26 Oct 2020 • Sebastian Wagner-Carena, Ji Won Park, Simon Birrer, Philip J. Marshall, Aaron Roodman, Risa H. Wechsler
We show that the posterior PDFs are sufficiently accurate (i. e., statistically consistent with the truth) across a wide variety of power-law elliptical lens mass distributions.
2 code implementations • 14 Aug 2020 • Simon Birrer, Tommaso Treu
Time-delay cosmography can reach sufficient precision to resolve the Hubble tension at 3-5$\sigma$, without assumptions on the radial mass profile of lens galaxies.
Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies
2 code implementations • 21 Jan 2020 • Lilan Yang, Simon Birrer, Tommaso Treu
For multiply-imaged sources, the tool can also fit and apply first (deflection) second (shear, convergence) and third order (flexion) corrections to the local gravitational potential to improve the overall reconstruction, depending on the quality of the data.
Astrophysics of Galaxies Instrumentation and Methods for Astrophysics
no code implementations • 5 Nov 2019 • Brian Nord, Andrew J. Connolly, Jamie Kinney, Jeremy Kubica, Gautaum Narayan, Joshua E. G. Peek, Chad Schafer, Erik J. Tollerud, Camille Avestruz, G. Jogesh Babu, Simon Birrer, Douglas Burke, João Caldeira, Douglas A. Caldwell, Joleen K. Carlberg, Yen-Chi Chen, Chuanfei Dong, Eric D. Feigelson, V. Zach Golkhou, Vinay Kashyap, T. S. Li, Thomas Loredo, Luisa Lucie-Smith, Kaisey S. Mandel, J. R. Martínez-Galarza, Adam A. Miller, Priyamvada Natarajan, Michelle Ntampaka, Andy Ptak, David Rapetti, Lior Shamir, Aneta Siemiginowska, Brigitta M. Sipőcz, Arfon M. Smith, Nhan Tran, Ricardo Vilalta, Lucianne M. Walkowicz, John ZuHone
The field of astronomy has arrived at a turning point in terms of size and complexity of both datasets and scientific collaboration.
1 code implementation • 17 Sep 2019 • Nikki Arendse, Radosław J. Wojtak, Adriano Agnello, Geoff C. -F. Chen, Christopher D. Fassnacht, Dominique Sluse, Stefan Hilbert, Martin Millon, Vivien Bonvin, Kenneth C. Wong, Frédéric Courbin, Sherry H. Suyu, Simon Birrer, Tommaso Treu, Leon V. E. Koopmans
Results from time-delay lenses are consistent with those from distance-ladder calibrations and point to a discrepancy between absolute distance scales measured from the CMB (assuming the standard cosmological model) and late-time observations.
Cosmology and Nongalactic Astrophysics
1 code implementation • 24 Apr 2019 • Simon Birrer, Tommaso Treu
The time delay between the arrival of photons of multiple images of time variable sources can be used to constrain absolute distances in the Universe (Refsdal 1964), and in turn obtain a direct estimate of the Hubble constant and other cosmological parameters.
Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies
12 code implementations • 26 Mar 2018 • Simon Birrer, Adam Amara
The software is also able to reconstruct complex extended sources (Birrer et.
Cosmology and Nongalactic Astrophysics