Ohio State is in the process of revising websites and program materials to accurately reflect compliance with the law. While this work occurs, language referencing protected class status or other activities prohibited by Ohio Senate Bill 1 may still appear in some places. However, all programs and activities are being administered in compliance with federal and state law.

AstroParticle Lunch: Nobuyki Sakai (Osaka Univ)

astrolunch
Fri, November 21, 2025
11:30 am - 12:30 pm
Price Place PRB M2005

Nobuyki Sakai, a graduate student visiting from Osaka University in Japan
 
Title: Gamma-Ray Emission from AGN Disk Winds: A Case Study of the Nearby Seyfert Galaxy GRS 1734−292
 
Abstract: Recent Fermi-LAT observations have revealed GeV gamma-ray emission from several radio-quiet Seyfert galaxies, challenging the traditional view that powerful jets are required to produce high-energy gamma rays in active galactic nuclei (AGNs). One such object, GRS 1734-292, is a nearby Seyfert galaxy with empirically weak starburst and jet activity, yet it exhibits a significant gamma-ray signal. In this talk, we present the first comprehensive multiwavelength modeling of GRS 1734−292 and investigate whether its gamma-ray emission can be attributed to an AGN disk wind. We model lepto-hadronic emission from a shocked interstellar medium (ISM) and a shocked wind region created by the interaction between the disk wind and the surrounding ISM. We identify two viable emission scenarios: a hadronic (pp-dominated) scenario and a leptonic (external-Compton-dominated) scenario, both consistent with the observed Fermi-LAT spectrum and multiwavelength constraints. Our results suggest that future observations with CTAO and SWGO could detect TeV emission from a disk wind in this source. Moreover, in the pp-dominated scenario, the disk wind could accelerate cosmic-ray protons beyond 1 EeV, offering new insights into the role of radio-quiet Seyfert galaxies as potential sources of ultrahigh-energy cosmic rays.

Filed in: