2018 Fiscal Year Annual Research Report
The evolution of the stellar IMF with HSC strong lenses
| Project/Area Number |
17K14250
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
Sonnenfeld Alex 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (40772827)
|
|---|
| Project Period (FY) |
2017-04-01 – 2019-03-31
|
| Keywords | Strong lenses / Stellar IMF |
|---|
| Outline of Annual Research Achievements |
The main goal of this project is to use strong gravitational lensing to study the stellar initial mass function (IMF) of massive early-type galaxies.The plan to achieve this goal consists in creating a large sample of strong lenses using photometric data from the Hyper Suprime-Cam (HSC) survey, following up the sample with spectroscopic observations, and carrying out a statistical study of the stellar IMF in the lens galaxies.
In FY2018, I led a citizen science project aimed at discovering new strong lenses in HSC data. In this project, hosted on the 'zooniverse'platform (spacewarps.org), we let volunteers classify 300,000 HSC images of galaxies based on the presence of strong lenses. I was responsible for the definition of the sample, the creation of the images and the generation of simulated lenses to be used for training purposes.The campaign is over: we collected over 3,000,000 classifications from more than 6,000 volunteers.The analysis of the results is in progress, but we expect bewteen 100 and 300 new lenses to be discovered from this effort.
In parallel, I started a study of the stellar IMF of a sample of 23 HSC lenses at redshift 0.6 with available spectroscopic data.Results are still preliminary, but the data allow us to exclude a bottom-heavy IMF for the average IMF of our strong lenses.This is a very interesting result, because it contrasts with some claims made using spectral fitting techniques on local galaxies.
|
Research Products
(3 results)
