Title：No Cluster Left Behind: Multiwavelength Cluster Count Cosmology with All the Data

speaker：Conghao Zhou

 

Abstract：
Cluster abundance is among the most powerful cosmological probes, but its constraining power is currently limited by systematic uncertainties in mass calibration. Optically selected samples in particular suffer from line-of-sight projection effects that bias both richness and lensing measurements. Jointly modeling clusters observed across multiple wavelengths offers a path to self-calibrating these systematics — yet previous multiwavelength analyses have typically discarded clusters lacking tSZ or X-ray counterparts, sacrificing much of the sample's statistical power. In this talk, I will present an analysis framework that retains every cluster detected in at least one survey: no cluster left behind. Applying it to Dark Energy Survey and South Pole Telescope data, I will show joint constraints on cluster mass calibration and optical projection effects. I will conclude with forecasts for multiwavelength cluster cosmology in the era of Rubin, Roman, the Simons Observatory, and eROSITA.

 

Bio:

Conghao Zhou is a Ph.D. candidate in Physics at UC Santa Cruz. He is interested in galaxy cluster cosmology, low surface brightness photometry, stellar halo science, pixel-to-object pipelines, and dwarf galaxies. He is a member of the Rubin, DES, DESI, and Merian collaborations.

 

Time: 14:00-15:00, 14/July, Tuesday
Venue: Room 506 (Large seminar room), Department of Astronomy