Yilun Ma (Princeton University)

Title: From Deep Fields to the Wide Sky: Tracing Little Red Dots Across Cosmic Time
 

Abstract:  Little red dots  are an abundant population of red, compact, broad-line objects discovered by JWST at z=5-8. No existing models can fully explain their SEDs, which are V-shaped in the UV-optical and not strongly detected at other wavelengths. In this talk, I will first briefly review the challenges in understanding the SED of LRDs with JWST. I will then discuss our extensive effort to understand the demographics of LRDs across cosmic time as they are 100x more abundant than quasars at z>5 but rarely identified at cosmic noon. 

I will present our search for LRDs at 2<z<5 using wide-area, ground-based, multi-wavelength imaging surveys, spectroscopic follow-up campaigns and JWST observations. I will discuss our result from this search, including a dramatic number density decline towards lower redshift and a steep cutoff in luminosity functions of LRDs, as well as their implications to the LRD population and more broadly black hole growth. Finally, I will mention our planned multi-wavelength follow-ups of the low-redshift LRDs in the future to understand the nature of these intriguing sources.