Title: Studying Hyperluminous Infrared Galaxies with Strong Gravitational Lensing

Speaker: Professor Q. Daniel Wang (University of Massachusetts, Amherst)

Time: 14:00pm, March 19, 2024

Location: 3-302, PMO Xianlin Campus

Abstract: Hyperluminous infrared Balaxies (HyLIRGs) are the brightest galaxies in the Universe. Identified by their extremely high intrinsic infrared (IR) luminosity, such galaxies are rare and typically found at z > 2. I'll first introduce the Planck All Sky Survey for the Analysis Gravitationally Lensed Extreme Starbursts (PASSAGES). This survey provides a sample of 30 gravitationally lensed DSFGs. Taking advantage of the strong lensing magnification, we have made extensive multi-wavelength observations of these DSFGs, many of which are found to be intrinsically HyLIRGs. I'll then focus on a large XMM-Newton observing program to probe the accreting black hole population in three PASSAGES HyLIRGs. The X-ray emission in one of them seems to be dominated by high-mass X-ray binaries (HMXBs). Remarkably, the luminosity of this non-AGN X-ray emission exceeds the value obtained by calibration with local galaxies by a factor of about three. This enhanced X-ray emission most likely highlights the efficacy of dynamical HMXB production within compact clusters, which is an important mode of star formation in HyLIRGs. The remaining two morphologically and spectrally show a compact X-ray component in addition to the extended non-AGN X-ray emission, indicating the presence of AGNs. They show intriguing properties and may play an important role in the formation and evolution of HyLIRGs, which are still largely uncertain and need to be further studied.