The Era of Binary Supermassive Black Holes: Coordination of Nanohertz-Frequency Gravitational-Wave Follow-up
Aspen Center for Physics, February 2-7 2025
Join us for in-depth discussions on planning for the identification of hosts of binary
supermassive black holes (MBHs) through coordination between pulsar timing arrays
(PTAs) and electromagnetic instruments!
PTAs are expected to begin resolving individual binary MBHs from the gravitational-wave
background in the next few years. The first few detections from PTAs will represent
the first conclusive identifications of binary supermassive black holes, however
will be poorly localized on the sky, potentially spanning regions of up to several
thousand square degrees (containing 100’s to 1000’s of candidate galaxies). Therefore,
extensive follow-up observations with a broad range of upcoming astrophysical
instruments, coupled with historical archives to track long-term signal evolution,
will be required to conclusively identify the host galaxies of these systems.
Building toward the first CW detection, significant questions remain that can only
be brought through a timely discussion between PTA scientists, electromagnetic
observers, and theorists. These critical questions include:
- How can upcoming electromagnetic surveys optimize the balance of sensitivity/field of view for the MMA identification of PTA detections?
- How can PTA and electromagnetic observing communities leverage the large ecosystem of multimessenger coordination infrastructure that have been developed for high-frequency gravitational-wave observations?
- What theorized electromagnetic signatures of binary MBHs require further inspection, and do current/future facilities enable observations of them?
- Are there critical observing capabilities for this science case that are not going to be realized by planned facilities?
As we enter this significant era of first discovery, coordination is crucial: rich
science will come from the identification of host galaxies of continuous-wave
detections. This pursuit will necessarily involve a broad-strokes multi-wavelength
effort, coordinated between PTAs, astronomical archives, new wide-field surveys,
and new targeted observations. In this era of imminent continuous-wave detections
by PTAs, it will be important to provide a roadmap towards observational coordination
between these efforts. This workshop will draw a broad range of electromagnetic
and gravitational-wave observers, large-survey scientists, and astronomy cyber-infrastructure
scientists, to plan and coordinate such follow-up. We anticipate that this Aspen
meeting will facilitate new collaborations and lead to significantly accelerated
progress in this field. This conference will include workshop-style elements,
bringing together critical players in PTA continuous-wave searches, MBH binary
evolution theory, MBH binary observation, multi-messenger cyberinfrastructure,
and astronomical observing and archiving facilities to address the above questions
and build new collaborative links across the multi-messenger spectrum.
Scientific Organizing Committee:
- Sarah Burke-Spolaor (Chair, sarah.spolaor@mail.wvu.edu)
- Tamara Bogdanovic
- Mike Eracleous
- Matthew Graham
- Kayhan Gultekin (kayhan+aspenw24@umich.edu)
- Jeffrey Hazboun (jeffrey.hazboun@oregonstate.edu)
- Chiara Mingarelli (chiara.mingarelli@yale.edu)
- Gautham Narayan
Event and Participant financial support:
We gratefully acknowledge support from the Research Corporation for Science Advancement: nurturing teacher-scholars and innovative basic research in the physical sciences at American and Canadian colleges and universities since 1912. We also gratefully acknowledge support from NANOGrav NSF Physics Fronter Center.