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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"

32479 results found.

  1. IPN triangulation of GRB 260706B
  2. GRB 260718A: SVOM/ECLAIRs refined analysis
  3. EP260723a: SVOM/VT optical observation
  4. EP260723a: COLIBRÍ optical observations
  5. EP260723a: NOT optical conterpart confirmation
  6. EP260723a: Liverpool Telescope likely optical counterpart
  7. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  8. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  9. Konus-Wind detection of GRB 260721A
  10. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  11. GRB 260721A: NuSTAR detection of prompt emission
  12. Konus-Wind detection of GRB 260714B
  13. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  14. GRB 260705A: Retraction of optical counterpart
  15. GRB 260714B: Insight-HXMT/HE detection
  16. GRB 260718A: EP-FXT follow-up observation
  17. Fermi GRB 260718A: Global MASTER-Net observations report
  18. GRB 260718A: LCO optical upper limits
  19. GRB 260711A: SVOM/GRM observation
  20. GRB 260710A: SVOM/GRM observation
  21. GRB 260718A: Fermi GBM Observation
  22. GRB 260718A : GRANDMA and KNC upper limits
  23. GRB 260718A: SVOM/VT optical upper limits
  24. GRB 260718A: SVOM/VT optical upper limits from VHF data
  25. GRB 260718A: SVOM detection of a burst
  26. GRB 260714B: SVOM/GRM observation
  27. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  28. GRB 260714B: GECAM-B observation of a burst
  29. GRB 260618B: EP-FXT follow-up observation upper limit
  30. GRB 260714B: COLIBRÍ optical counterpart candidate
  31. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  32. SVOM sb26071506: Global MASTER-Net observations report
  33. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  34. EP260703a: SVOM/ECLAIRs Upper Limit
  35. GRB 260710A: AstroSat CZTI detection
  36. GRB 260709A: AstroSat CZTI detection
  37. GRB 260714B: AstroSat CZTI detection
  38. GRB 260714B: Fermi-LAT detection
  39. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  41. GRB 260706A: ATCA detection of possible radio counterpart
  42. GRB 260705A: ATCA radio observations
  43. GRB 260619A: SVOM/VT continuous optical observations
  44. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  45. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  46. EP260623a: KAIT optical observations
  47. EP260711a: EP-FXT follow-up observation
  48. GRB 260708A: GRANDMA Optical Observations
  49. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  50. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  51. GRB 260710A: Insight-HXMT/HE detection
  52. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  53. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  54. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 260708A: LCO optical observations
  56. GRB 260710A: Fermi GBM Detection
  57. GRB 260709A: SVOM/GRM detection
  58. GRB 260709A: GECAM-B observation
  59. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  60. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  61. GRB 260705C: AstroSat CZTI detection
  62. GRB 260708A: Glowbug gamma-ray detection
  63. GRB 260704A: SVOM/ECLAIRs refined analysis
  64. GRB 260706A : GRANDMA Upper limits
  65. GRB 260708A: Kilonova-Catcher optical afterglow detection
  66. GRB 260708A: GECAM-B observation of a burst
  67. IceCube-260708A: One candidate from the Zwicky Transient Facility
  68. GRB 260708A: Fermi-GBM observation
  69. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  70. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  71. GRB 260708A: Fermi-LAT detection
  72. GRB 260705B: SVOM/GRM observation
  73. GRB 260706A: Further EP-FXT follow-up observation
  74. GRB 260706A: SVOM/VT optical upper limits
  75. EP260707a (by EP-FXT): NOT optical upper limit
  76. EP260707a is not a real source
  77. EP260707a: LCOGT Optical Upper Limit
  78. EP260707a: TRT optical upper limit
  79. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  80. GRB 260705C: Glowbug gamma-ray detection of a short burst
  81. GRB 260706A: SVOM/ECLAIRs refined analysis
  82. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  83. GRB 260706A: SVOM/GRM observation
  84. GRB 260706A: REM optical/NIR observations
  85. IceCube-260704A: No candidates from the Zwicky Transient Facility
  86. GRB 260706A: LCO optical upper limit
  87. GRB 260706A: EP-FXT follow-up observation
  88. GRB 260706A: Fermi GBM Observation
  89. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  90. IPN triangulation of GRB 260627A
  91. GRB 260705A: SVOM/ECLAIRs refined analysis
  92. GRB 260706A: SVOM detection of a burst
  93. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  94. IceCube260704A: OHP/T193 optical observations
  95. GRB 260705A: LCO optical upper limits
  96. GRB 260704A: NOT optical upper limits
  97. Fermi GBM Sub-Threshold Detection of GRB 260705A
  98. GRB 260704A: EP-FXT follow-up observation
  99. GRB 260629A: SVOM/GRM observation of a short burst
  100. GRB 260629A: GECAM-A observation of a short burst

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