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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"

32482 results found.

  1. GRB 260602B: cubesat Avion detection
  2. GRB 260601A: cubesat Avion detection
  3. EP260723a: EP-FXT follow-up observation
  4. IPN triangulation of GRB 260706B
  5. GRB 260718A: SVOM/ECLAIRs refined analysis
  6. EP260723a: SVOM/VT optical observation
  7. EP260723a: COLIBRÍ optical observations
  8. EP260723a: NOT optical conterpart confirmation
  9. EP260723a: Liverpool Telescope likely optical counterpart
  10. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  12. Konus-Wind detection of GRB 260721A
  13. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 260721A: NuSTAR detection of prompt emission
  15. Konus-Wind detection of GRB 260714B
  16. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  17. GRB 260705A: Retraction of optical counterpart
  18. GRB 260714B: Insight-HXMT/HE detection
  19. GRB 260718A: EP-FXT follow-up observation
  20. Fermi GRB 260718A: Global MASTER-Net observations report
  21. GRB 260718A: LCO optical upper limits
  22. GRB 260711A: SVOM/GRM observation
  23. GRB 260710A: SVOM/GRM observation
  24. GRB 260718A: Fermi GBM Observation
  25. GRB 260718A : GRANDMA and KNC upper limits
  26. GRB 260718A: SVOM/VT optical upper limits
  27. GRB 260718A: SVOM/VT optical upper limits from VHF data
  28. GRB 260718A: SVOM detection of a burst
  29. GRB 260714B: SVOM/GRM observation
  30. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  31. GRB 260714B: GECAM-B observation of a burst
  32. GRB 260618B: EP-FXT follow-up observation upper limit
  33. GRB 260714B: COLIBRÍ optical counterpart candidate
  34. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  35. SVOM sb26071506: Global MASTER-Net observations report
  36. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  37. EP260703a: SVOM/ECLAIRs Upper Limit
  38. GRB 260710A: AstroSat CZTI detection
  39. GRB 260709A: AstroSat CZTI detection
  40. GRB 260714B: AstroSat CZTI detection
  41. GRB 260714B: Fermi-LAT detection
  42. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  43. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  44. GRB 260706A: ATCA detection of possible radio counterpart
  45. GRB 260705A: ATCA radio observations
  46. GRB 260619A: SVOM/VT continuous optical observations
  47. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  48. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  49. EP260623a: KAIT optical observations
  50. EP260711a: EP-FXT follow-up observation
  51. GRB 260708A: GRANDMA Optical Observations
  52. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  53. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  54. GRB 260710A: Insight-HXMT/HE detection
  55. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  56. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  57. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 260708A: LCO optical observations
  59. GRB 260710A: Fermi GBM Detection
  60. GRB 260709A: SVOM/GRM detection
  61. GRB 260709A: GECAM-B observation
  62. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  63. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  64. GRB 260705C: AstroSat CZTI detection
  65. GRB 260708A: Glowbug gamma-ray detection
  66. GRB 260704A: SVOM/ECLAIRs refined analysis
  67. GRB 260706A : GRANDMA Upper limits
  68. GRB 260708A: Kilonova-Catcher optical afterglow detection
  69. GRB 260708A: GECAM-B observation of a burst
  70. IceCube-260708A: One candidate from the Zwicky Transient Facility
  71. GRB 260708A: Fermi-GBM observation
  72. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  73. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 260708A: Fermi-LAT detection
  75. GRB 260705B: SVOM/GRM observation
  76. GRB 260706A: Further EP-FXT follow-up observation
  77. GRB 260706A: SVOM/VT optical upper limits
  78. EP260707a (by EP-FXT): NOT optical upper limit
  79. EP260707a is not a real source
  80. EP260707a: LCOGT Optical Upper Limit
  81. EP260707a: TRT optical upper limit
  82. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  83. GRB 260705C: Glowbug gamma-ray detection of a short burst
  84. GRB 260706A: SVOM/ECLAIRs refined analysis
  85. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  86. GRB 260706A: SVOM/GRM observation
  87. GRB 260706A: REM optical/NIR observations
  88. IceCube-260704A: No candidates from the Zwicky Transient Facility
  89. GRB 260706A: LCO optical upper limit
  90. GRB 260706A: EP-FXT follow-up observation
  91. GRB 260706A: Fermi GBM Observation
  92. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  93. IPN triangulation of GRB 260627A
  94. GRB 260705A: SVOM/ECLAIRs refined analysis
  95. GRB 260706A: SVOM detection of a burst
  96. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  97. IceCube260704A: OHP/T193 optical observations
  98. GRB 260705A: LCO optical upper limits
  99. GRB 260704A: NOT optical upper limits
  100. Fermi GBM Sub-Threshold Detection of GRB 260705A

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