LSS open group seminar:  David Sanchez (Ciemat, Spain) and John Hood (Vanderbilt / UChicago)

1:00–2:00 pm ERC 419

David Sanchez  (Ciemat, Spain) "Constraining cosmological models with galaxy clustering and weak lensing data"

We are currently involved in the endgame of Stage III cosmological surveys. A remarkable milestone of this final period will be the analysis of the Dark Energy Survey (DES) Year 6 data. In the meantime, cosmologists must get prepared for the next generation of surveys. Rubin Observatory Legacy Survey of Space and Time (LSST) Dark Energy Science Collaboration (DESC) will be one of the main flagships of Stage IV projects to unveil the nature of dark energy. In this talk I will present preliminary results on the first harmonic space joint analysis of galaxy clustering, cosmic shear and galaxy-galaxy lensing, the so-called $3 \times 2$pt analysis using Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) public data. HSC is the deepest Stage III survey and uses a prototype version of the Rubin Science Pipelines, making this dataset ideal to use as a precursor to the LSST DESC. These characteristics allow us to put to the test software and tools developed by the LSST DESC collaboration as well as setting precise constraints on LCDM cosmological parameters. In this analysis we explore the applicability of mode deprojection as a method to correct the impact of observing conditions in spin-2 fields. As our main result, we aim to set constraints in the plane $\Omega_m - S_8$ that are competitive with the current state of the art.

John Hood (Vanderbilt / UChicago) "MM-wave AGN Monitoring with SPTPol 500^2 degree survey"

While continuous high-cadence monitoring of active galactic nuclei (AGN) is common at \gr, optical, and radio wavelengths, AGN monitoring in the millimeter (mm) band has mostly been restricted to short campaigns on targeted sources. Cosmic microwave background (CMB) telescopes are now providing an option for daily mm-wave monitoring of these objects in increasingly larger fields of view. Here we report on a pilot study using the SPTpol instrument on the South Pole Telescope (SPT), which was designed to observe the CMB at arcminute and larger angular scales, to monitor AGN. Between 2013 and 2016, SPTpol was used to continuously scan a 500 deg2 field, covering the entire field several times per day with detectors sensitive to radiation in bands centered at 95 and 150 GHz. We use SPT 150 GHz observations to create AGN light curves in the mm band and compare those to light curves at other wavelengths, in particular gamma-ray and optical. In this pilot study, our focus source is PKS 2326-502, which has extensive, day-timescale monitoring data in gamma-ray, optical, and now mm-wave between 2013 and 2016. We find PKS 2326-502 to be in a flaring state in the first two years of this monitoring, and we present a search for evidence of correlated variability between SPT (150 GHz), SMARTS (R band) and Fermi (gamma-ray) observations. This pilot study is paving the way for AGN monitoring with current and upcoming CMB experiments such as SPT-3G, Simons Observatory, and CMB-S4, including multi-wavelength studies with facilities such as VRO-LSST.

Event Type


May 19