Aims and Scope

The Black Hole Explorer (BHEX) is a space mission concept being developed for the NASA Explorers Program. BHEX will produce the sharpest images in the history of astronomy by extending submillimeter Very Long Baseline Interferometry (VLBI) to space. The primary objective of BHEX is to detect and measure a black hole’s “photon ring,’’ composed of rays of light that have orbited the black hole before escaping. The photon ring traces a narrow region of space just outside the black hole’s event horizon, which is a unique probe for its spacetime and enables direct measurements of the black hole’s spin. BHEX will achieve these goals by extending the existing ground-based millimeter/submillimeter VLBI arrays (EHT and GMVA) to space at the observing frequencies of 86, 230, and 345 GHz. 

The Japanese community is a major contributor to the mission concept development from science to instrument design. Potential key technological contributions to the mission include key components of the receiver front end, the development of a novel space-qualified multi-stage 4.5K cryocooler similar to that flown on the JAXA’s Hitomi and XRISM satellites, the ground support using millimeter/submillimeter observatories including VERA, Nobeyama 45-m, and ALMA, and using the network of optical downlink stations for ground-to-space laser communications. The community’s scientific interests span from physics at the edge of the event horizon, astrophysics of black hole accretion and jets, to the molecular universe to be potentially explored at radio frequencies for the first time observed with the mission. This community plans to co-propose the mission to JAXA as a collaborative US-Japan space program.

This two-day workshop aims to connect the BHEX community with broad regional astronomy and space science communities. This workshop features keynote speakers from the BHEX team and the broader astronomical community to summarize the mission concept development and crucial contributions from  Japan.

We will further invite oral and poster contributions regarding broad topics relevant to the mission including:

• Science Drivers and Requirements
  • Photon ring and fundamental physics (BH properties, tests of GR, EM/GW studies, dark matter, exotic compact objects)
  • Black holes and their cosmic context (SMBH formation and evolution, studies of SMBH binaries, multi-wavelength studies of black holes and jets, large-scale jet collimation and kinematics)
  • Accretion (probing accretion flow dynamics and structure, turbulence, plasma studies near a BH)
  • Jet launching (energy extraction from spinning BHs, black hole magnetospheres, jet kinematics and monitoring)
  • Transients and impulsive phenomena (incoherent transients including XRBs, TDEs, and SNe, GW precursor/afterglow studies)
  • Algorithms and inference (imaging methods, model fitting to interferometric data, feature extraction, machine learning, parameter estimation, synthetic data)
  • Community Science (Single-dish Opportunities)
• Operations and Instrumentations
  • Antenna and Optics
  • Cryogenics and Recievers
  • Backend, Buffer and Downlink
  • Frequency Reference
  • Science Operations
  • Flight Dynamics and Orbit Optimization

Important Dates