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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"

26 results found.

  1. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  2. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  3. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  4. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  5. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  6. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345)
  7. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345).
  8. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  9. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  10. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  11. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  12. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  13. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  14. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  15. LIGO/Virgo/KAGRA S241125n: HCT upper limit
  16. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  17. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  18. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  19. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  20. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  21. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  22. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  23. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  24. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  25. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  26. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate

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