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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"

19572 results found.

  1. GRB 260714B: COLIBRÍ optical counterpart candidate
  2. sb26071506: SVOM detection of a X-ray transient
  3. EP260703a: SVOM/ECLAIRs Upper Limit
  4. GRB 260709A: AstroSat CZTI detection
  5. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  6. GRB 260706A: ATCA detection of possible radio counterpart
  7. GRB 260705A: ATCA radio observations
  8. EP260713a: Einstein Probe detection of an X-ray transient
  9. EP260623a: KAIT optical observations
  10. GRB 260708A: GRANDMA Optical Observations
  11. GRB 260708A: LCO optical observations
  12. EP260711a: Einstein Probe detection of an X-ray transient
  13. GRB 260709A: SVOM/GRM detection
  14. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  15. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  16. GRB 260706A : GRANDMA Upper limits
  17. GRB 260708A: Kilonova-Catcher optical afterglow detection
  18. IceCube-260708A: One candidate from the Zwicky Transient Facility
  19. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  20. GRB260708B: MAXI/GSC detection
  21. GRB 260705B: SVOM/GRM observation
  22. EP260707a (by EP-FXT): NOT optical upper limit
  23. EP260707a is not a real source
  24. EP260707a: LCOGT Optical Upper Limit
  25. EP260707a: TRT optical upper limit
  26. EP260707a: Einstein Probe detection of an X-ray transient
  27. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  28. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  29. GRB 260706A: SVOM/GRM observation
  30. GRB 260706A: REM optical/NIR observations
  31. GRB 260706A: LCO optical upper limit
  32. GRB 260706A: SVOM detection of a burst
  33. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  34. GRB 260705A: LCO optical upper limits
  35. GRB 260704A: NOT optical upper limits
  36. Fermi GBM Sub-Threshold Detection of GRB 260705A
  37. GRB 260705A: SVOM detection of a burst
  38. GRB 260629A: SVOM/GRM observation of a short burst
  39. GRB 260629A: AstroSat CZTI detection
  40. GRB 260704A: SVOM detection of a possible GRB
  41. EP260703a: EP-WXT detection of a fast X-ray transient
  42. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  43. GRB 260614B: ATCA Radio Upper Limits
  44. EP260628a: EP-WXT detection of a fast X-ray transient
  45. EP260626a: further Liverpool Telescope optical upper limits
  46. EP260626a: COLIBRÍ optical upper limit
  47. EP260626a: Liverpool Telescope upper limits
  48. EP260626a: EP-WXT detection of a fast X-ray transient
  49. Konus-Wind detection of GRB 260623B / EP260623a
  50. EP260623a: TNG NIR afterglow detection
  51. GRB 260619A: SVOM/ECLAIRs refined analysis
  52. EP260623a: Liverpool Telescope optical observations
  53. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  54. EP260623a: WINTER J-band observations
  55. EP260623a: Optical follow-up observations with Kinder
  56. EP260623a: SVOM/VT optical observations
  57. EP260623a: TRT optical observations
  58. EP260623a: REM optical/NIR afterglow detection
  59. EP 260623a: COLIBRÍ optical observations
  60. EP260623a: Las Cumbres discovery of the optical counterpart
  61. EP260623a: Einstein Probe detection of an X-ray transient
  62. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  63. EP260618a: Liverpool Telescope optical observations
  64. GRB 260618B: LCO optical observations
  65. EP260618a: JinShan optical observations
  66. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  67. GRB 260619A: TRT optical counterpart confirmation
  68. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  69. GRB 260604B: 239Alferov CubeSat detection
  70. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  71. GRB 260616A: SVOM/GRM observation
  72. EP260618a: OHP/T193 optical observations
  73. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  74. GRB 260619A: Kilonova-Catcher optical upper limit
  75. EP260618a: LCO optical counterpart confirmation
  76. EP260618a: COLIBRÍ optical counterpart candidate
  77. GRB 260619A: SVOM possible detection of a faint burst
  78. EP260618a: EP-WXT detection of an X-ray transient
  79. GRB 260610B: AbAO optical observations
  80. GRB 260506B: cubesat Avion detection
  81. GRB 260616C: GECAM-B observation of a burst
  82. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  83. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  84. GRB 260429A: cubesat Avion detection
  85. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  86. EP260616a: EP-WXT detection of a fast X-ray transient
  87. GRB 260610B: Terskol optical observations
  88. GRB 260610B: SVOM/GRM observation
  89. GRB 260614B: SVOM/VT optical candidate from VHF data
  90. GRB 260614B: SVOM detection of a burst
  91. GRB 260611B: SVOM/GRM detection
  92. GRB 260603C: AstroSat CZTI detection
  93. GRB 260610B: further Liverpool Telescope optical observations
  94. GRB 260610B / AT2026owq: GRANDMA optical observations
  95. GRB 260610B / AT2026owq: further SAO RAS optical observations
  96. EP260605a: COLIBRÍ optical upper limits
  97. GRB 260610b: Liverpool Telescope optical observations
  98. EP260610b: Liverpool Telescope optical upper limits
  99. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  100. GRB 260610B / AT2026owq: OASDG optical observations

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