English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Very long baseline interferometry (VLBI) makes it possible to recover imagesof astronomical sources with extremely high angular resolution. Most recently,the Event Horizon Telescope (EHT) has extended VLBI to short millimeterwavelengths with a goal of achieving angular resolution sufficient for imagingthe event horizons of nearby supermassive black holes. VLBI providesmeasurements related to the underlying source image through a sparse setspatial frequencies. An image can then be recovered from these measurements bymaking assumptions about the underlying image. One of the most importantassumptions made by conventional imaging methods is that over the course of anight's observation the image is static. However, for quickly evolving sources,such as the galactic center's supermassive black hole (Sgr A*) targeted by theEHT, this assumption is violated and these conventional imaging approachesfail. In this work we propose a new way to model VLBI measurements that allowsus to recover both the appearance and dynamics of an evolving source byreconstructing a video rather than a static image. By modeling VLBImeasurements using a Gaussian Markov Model, we are able to propagateinformation across observations in time to reconstruct a video, whilesimultaneously learning about the dynamics of the source's emission region. Wedemonstrate our proposed Expectation-Maximization (EM) algorithm, StarWarps, onrealistic synthetic observations of black holes, and show how it substantiallyimproves results compared to conventional imaging algorithms. Additionally, wedemonstrate StarWarps on real VLBI data of the M87 Jet from the VLBA.

Reconstructing Video from Interferometric Measurements of Time-Varying Sources