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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').

8 results found.

  1. GRB 090904B: GROND detection of the optical afterglow
  2. GRB 090904B: Swift/UVOT Refined Analysis
  3. GRB 090904B: Fermi GBM detection
  4. GRB 090904B: Swift XRT Refined Analysis
  5. GRB 090904B: MOA-II Optical observation
  6. GRB 090904B: Swift-BAT refined analysis
  7. GRB 090904B: Enhanced Swift-XRT position
  8. GRB 090904B: Swift detection of a burst


Download all Circulars as a .tar.gz archive:
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