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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28 results found.

  1. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  2. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  3. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  4. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  5. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  6. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  7. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  8. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  9. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  10. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  11. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  12. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  13. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  14. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
  15. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  16. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  17. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  18. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  19. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  20. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  21. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  22. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  23. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  24. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  25. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  26. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  27. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  28. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate

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