Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

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').

21 results found.

  1. LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
  2. LIGO/Virgo S190412m: SVOM/GWAC observations of the initial skymap
  3. LIGO/Virgo S190412m: TAROT-GRANDMA observation report.
  4. LIGO/Virgo S190412m: Palomar Gattini-IR Wide-field Infrared Follow-up
  5. LIGO/Virgo S190412m: GOTO optical coverage - no notable counterparts
  6. LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
  7. LIGO/Virgo S190412m: Swift/BAT data search
  8. LIGO/Virgo S190412m: J-GEM optical/NIR follow-up observations
  9. LIGO/Virgo S190412m: Fermi-GBM Observations
  10. LIGO/Virgo S190412m: MAXI/GSC Observations
  11. LIGO-Virgo S190412m: AGILE GRID observations
  12. LIGO/Virgo S190412m: Insight-HXMT/HE observation
  13. LIGO/Virgo S190408an: ATLAS observations of the S190412m skymap
  14. LIGO/Virgo S190412m/G329483: ANTARES neutrino search
  15. LIGO/Virgo S190412m: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  16. LIGO-Virgo S190412m: Search for neutrino counterparts with IceCube
  17. LIGO/Virgo S190412m: HAWC follow-up
  18. INTEGRAL prompt observation of S190412m
  19. LIGO-Virgo S190412m: AGILE preliminary analysis
  20. LIGO/Virgo S190412m: MASTER early alert observation
  21. LIGO/Virgo S190412m: Identification of a GW binary merger candidate


Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit