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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"

25 results found.

  1. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  2. LIGO/Virgo S200224ca: Upper limits from Konus-Wind observations
  3. LIGO/Virgo S200224ca: DESGW Summary of DECam Observations
  4. LIGO/Virgo S200224ca: No counterpart candidates in TOROS observations
  5. LIGO/Virgo S200224ca: Transient found in Swift/UVOT counterpart search
  6. LIGO/Virgo S200224ca: Updated Sky Localization and EM Bright Classification
  7. LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
  8. LIGO/Virgo S200224ca: Upper limits from CALET observations.
  9. LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
  10. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  11. LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
  12. LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
  13. LIGO/Virgo S200224ca: No counterpart candidates in KAIT observations
  14. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  15. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  16. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  17. LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
  18. LIGO/Virgo S200224ca: upper limits from AGILE/GRID observations
  19. LIGO/Virgo S200224ca: not observable by Fermi-GBM
  20. LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  21. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo S200224ca: upper limits from AGILE/MCAL observations
  23. LIGO/Virgo S200224ca: Global MASTER-Net observations report
  24. LIGO/Virgo S200224ca: Upper limits from IceCube neutrino searches
  25. LIGO/Virgo S200224ca: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration

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