My research focuses on studying super massive black holes with sufficient resolution to directly observe the event horizon. To do this our group assembles global networks of telescopes that observe at mm wavelengths to create an Earth-size virtual telescope using the technique of Very Long Baseline Interferometry (VLBI). We target SgrA*, the 4 million solar mass black hole at the center of the Milky Way, and M87, a giant elliptical galaxy for this work. Both of these objects present to us the largest apparent event horizons in the Universe, and both can be resolved by (sub)mm VLBI arrays. We call this project The Event Horizon Telescope (EHT).
A link to a white paper describing the EHT can be found here.
The website for the Event Horizon Telescope contains more scientific, logistical, and technical details.
EHT Observational Results.
- Resolving the Jet-Launch Region of the M87 Supermassive Black Hole
- Detection of Event-Horizon-Scale structure in SgrA*.
- Detection of Time Variable structure in SgrA*.
Fitting Physical Models to 1.3mm VLBI data on SgrA*
- Estimating Spin, Disk Inclination, and Orientation using Physical Models of SgrA*.
- Using Closure Phase to further constrain RIAF models.
Simulations: Future EHT Observations.
As the EHT is built out from the initial 3-station array to include sites spanning the Globe, imaging fidelity and the ability to monitor time variable structures near the event horizon will grow. Using RIAF models, realistic synthetic data sets from future EHT arrays have been created. Analysis of these data sets shows that 0.8/1.3mm VLBI observations can place tight constraints on SgrA* emission models and allow searches for periodicity associated with orbits near the black hole.