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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"

40 results found.

  1. LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
  2. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  3. LIGO/Virgo S191216ap: Updated Source Classification
  4. LIGO/Virgo S191216ap: Upper limits from Insight-HXMT/HE observations
  5. LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
  6. LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
  7. LIGO/Virgo S191216ap: No radio candidates so far in the VLA/JAGWAR galaxy targeted search
  8. LIGO/Virgo S191216ap: MASTER optical observation
  9. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  10. LIGO/Virgo S191216ap: AstroSat CZTI upper limits
  11. LIGO/Virgo S191216ap: Subaru/Hyper Suprime-Cam observations of GW+IceCube+HAWC error region
  12. LIGO/Virgo S191216ap: UPDATED list of galaxies coincident with LIGO/Virgo LALInference skymap and HAWC positions
  13. LIGO/Virgo S191216ap: Updated Sky Localization
  14. LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
  15. LIGO/Virgo S191216ap: No candidates found in J-GEM follow-up observations of HAWC error region
  16. LIGO/Virgo S191216ap: Correction to GCN 26488 (NOWT observations)
  17. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  18. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  19. LIGO/Virgo S191216ap and IceCube neutrino: no counterpart candidates from AGILE-GRID observations
  20. LIGO/Virgo S191216ap: GRAWITA Loiano observations of HAWC error region
  21. LIGO/Virgo S191216ap: No transient candidates in CALET observations
  22. LIGO/Virgo S191216ap: CORRECTED list of galaxies coincident with LIGO/Virgo and HAWC positions
  23. LIGO/Virgo S191216ap: Nanshan follow-up observations
  24. LIGO/Virgo S191216ap: galaxies consistent with GW + Neutrino + HAWC position
  25. LIGO/Virgo S191216ap and IceCube neutrino: Swift XRT sources
  26. LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
  27. LIGO/Virgo S191216ap: No significant counterpart candidates in SAGUARO observations
  28. LIGO/Virgo S191216ap: HAWC gamma-ray sub-threshold event coincident with LIGO/Virgo and IceCube localizations
  29. LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
  30. LIGO/Virgo S191216ap: no counterpart candidates in the Swift/BAT observations
  31. LIGO/Virgo S191216ap: No Candidates from the Zwicky Transient Facility
  32. LIGO/Virgo S191216ap: Correction to GCN 26460 (IceCube event coincident with GW event)
  33. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
  35. LIGO/Virgo S191216ap: 1 counterpart neutrino candidate from IceCube neutrino searches
  36. LIGO/Virgo S191216ap : no neutrino counterpart candidate in ANTARES search
  37. LIGO/Virgo S191216ap: Global MASTER-Net observations report
  38. LIGO/Virgo S191216ap: no INTEGRAL observation
  39. LIGO/Virgo S191216ap: No counterpart candidates in HAWC observations
  40. LIGO/Virgo S191216ap: Identification of a GW compact binary merger candidate

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