USAP-DC

\Millimeter-wave (mm-wave) observations of active galactic nucleus (AGN) variability have the potential to shed light on some of the key questions of AGN physics, such as the origin of blazar gamma-ray emission and the possible connection of AGN to the high-energy neutrinos detected by IceCube. While continuous, high-cadence monitoring of AGN is now common at gamma-ray, optical, and radio frequencies, AGN monitoring in the mm band has mostly been restricted to short campaigns on targeted sources. Cosmic Microwave Background (CMB) telescopes are now providing an option for daily monitoring of these objects within limited fields of view. I propose to use the South Pole Telescope (SPT), which was designed to observe the CMB at arcminute and larger angular scales, to monitor AGN, and then to expand this monitoring program to other CMB experiments such as Advanced ACTPol and the upcoming Simons Observatory and CMB-S4 experiments. A pilot project using data from the SPTpol camera on the SPT has enabled the monitoring of tens of mm-bright AGN on timescales from years to days at high signal to noise (S/N > 10 in a 36-hour coadd). A study focused on the blazar PKS 2326-502, which has extensive, day-timescale monitoring data in gamma-ray, optical, and now mm-wave data between 2013 and 2016 shows intriguing evidence of correlated variability between SPTpol (150 GHz), SMARTS (O/IR) and Fermi (gamma-rays) observations. I propose to carry out such multi-wavelength correlation studies on a large statistical sample of mm-wave-bright AGN, enabled by the repurposing of existing and future CMB data. This large sample (covering nearly 70 % of the sky) will also be key to investigating hints of correlations between mm-bright blazar flares and high-energy neutrinos. I further propose to build a public-facing server that will provide the mm lightcurves I construct from CMB data to the wider community.

Person	Role
Hood, John	Investigator and contact

Post Doc/Travel

Award # 2219065

USAP-2219065_1

None in the Database