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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"

2406 results found.

  1. GRB 260616A: SVOM/GRM observation
  2. GRB 260619A: Kilonova-Catcher optical upper limit
  3. GRB 260614B: NuSTAR detection of prompt emission
  4. GRB 260619A: SVOM possible detection of a faint burst
  5. GRB 260616A: Insight-HXMT detection
  6. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  7. GRB 260429A: cubesat Avion detection
  8. GRB 260604C: GRANDMA late observations with CFHT/MegaCam
  9. GRB 260614B: SVOM/ECLAIRs refined analysis
  10. GRB 260614B: GECAM-B observation
  11. GRB 260610B: SVOM/GRM observation
  12. GRB 260614B: SVOM/VT optical afterglow confirmation
  13. GRB 260614B: Fermi GBM Observation
  14. GRB 260614B: SVOM/VT optical candidate from VHF data
  15. GRB 260614B: SVOM detection of a burst
  16. GRB 260611B: SVOM/GRM detection
  17. GRB 260610B / AT2026owq: GRANDMA optical observations
  18. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  19. GRB 260610B / AT2026owq: SVOM/VT optical observations
  20. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  21. EP260610b: COLIBRÍ optical observations
  22. EP260610b: SVOM/VT optical confirmation with blue color
  23. EP260610a: SVOM/VT optical upper limits
  24. Konus-Wind detection of GRB 260601A
  25. IPN triangulation of GRB 260601A (short/hard)
  26. Konus-Wind detection of GRB 260604C
  27. GRB 260608A: Fermi GRB Observation
  28. GRB 260604C: AstroSat CZTI detection
  29. GRB 260604C: SVOM/ECLAIRs refined analysis
  30. GRB 260608A: SVOM/ECLAIRs refined analysis
  31. GRB 260604C: further SAO RAS optical observations
  32. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  33. GRB 260604C: SVOM/C-GFT upper limit
  34. GRB 260608A: SVOM detection of a burst
  35. GRB 260604C: GRANDMA further observations
  36. GRB 260604A: SVOM/GRM detection
  37. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  38. GRB 260604C: GECAM-B observation
  39. GRB 260604C: 6 GHz VLA observations
  40. GRB 260604C: SAO RAS optical observations
  41. GRB 260604C: GRANDMA observations
  42. GRB 260604B: SVOM/GRM detection
  43. GRB 260605A: Insight-HXMT/HE detection
  44. GRB260603A: SVOM/ECLAIRs refined analysis
  45. GRB 260604C: LCO optical upper limit
  46. GRB 260604C: GOTO detections of the optical afterglow
  47. GRB 260604C: Kilonova-Catcher optical afterglow detection
  48. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  49. GRB 260604C: Jinshan optical observations
  50. GRB 260604C: Fermi GBM Observation
  51. GRB 260604C: LAST detection of optical counterpart candidate
  52. SVOM GRB260604.85: Global MASTER-Net observations report
  53. GRB 260604C: SVOM detection of a long burst
  54. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  55. GRB 260603A: NOT optical observations
  56. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  57. GRB 260603A: EP-FXT follow-up observation
  58. GRB 260603A: Kilonova-Catcher optical upper limit
  59. GRB 260603A: SVOM/VT optical observations
  60. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  61. EP260602a: SVOM/VT optical magnitudes correction
  62. GRB 260601A: SVOM/GRM observation of a short burst
  63. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  64. SVOM GRB260603.23: Global MASTER-Net observations report
  65. GRB 260603A: SVOM detection of a burst
  66. EP260602a: SVOM/VT optical candidate
  67. GRB 260601B/EP260601a: SVOM/VT optical observations
  68. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  69. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  70. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  71. EP260526a: SVOM/VT optical upper limits
  72. EP260527a: SVOM/VT optical observation
  73. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  74. GRB 260522B: NuSTAR detection of prompt emission
  75. GRB 260519C: SVOM/GRM observation
  76. GRB 260511A: iTelescope T-75 optical detection
  77. GRB 260520B: SVOM/GRM observation
  78. GRB 260411B: TERI Gamma-ray detection
  79. GRB 260225D: TERI Gamma-ray detection
  80. GRB 260428A: TERI Gamma-ray detection
  81. GRB 260509A: SVOM/ECLAIRs refined analysis
  82. GRB 260519C: NuSTAR detection of prompt emission
  83. GRB 260516D: SVOM/ECLAIRs refined analysis
  84. GRB 260515A: SVOM/ECLAIRs refined analysis
  85. GRB 260421B: radio detection with the VLA
  86. GRID detection of GRB 260511A
  87. GRB 260516D: EP-FXT follow-up observation
  88. GRB 260516D: GOTO optical counterpart detection
  89. GRB 260516D: LCO optical observations
  90. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  91. GRB 260516D: SVOM/VT optical bright candidate
  92. GRB 260516D: FRAM-ORM optical limit
  93. SVOM GRB260516D: Global MASTER-Net observations report
  94. GRB 260516D: SVOM possible detection of a burst
  95. Konus-Wind detection of GRB 260515A
  96. GRB 260515A: LCO optical counterpart detection
  97. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  98. GRB 260515A: EP-FXT follow-up observation
  99. EP260514a: TRT optical counterpart candidate
  100. EP260514a: SVOM/VT optical candidate

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