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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"

20280 results found.

  1. GRB 260727A: Kilonova-Catcher optical upper limit
  2. GRB 260727A: LCO optical upper limits
  3. GRB 260726A: SVOM detection of a burst
  4. EP260725a: EP-WXT detection of an X-ray transient
  5. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  6. GRB 260601A: cubesat Avion detection
  7. GRB 260718A: SVOM/ECLAIRs refined analysis
  8. EP260723a: SVOM/VT optical observation
  9. EP260723a: COLIBRÍ optical observations
  10. EP260723a: NOT optical conterpart confirmation
  11. EP260723a: Liverpool Telescope likely optical counterpart
  12. EP260723a: EP-WXT detection of a fast X-ray transient
  13. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  14. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  15. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  16. GRB 260705A: Retraction of optical counterpart
  17. GRB 260718A: LCO optical upper limits
  18. GRB 260710A: SVOM/GRM observation
  19. GRB 260718A : GRANDMA and KNC upper limits
  20. GRB 260718A: SVOM/VT optical upper limits
  21. GRB 260718A: SVOM/VT optical upper limits from VHF data
  22. GRB 260714B: SVOM/GRM observation
  23. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  24. GRB 260714B: GECAM-B observation of a burst
  25. GRB 260714B: COLIBRÍ optical counterpart candidate
  26. sb26071506: SVOM detection of a X-ray transient
  27. EP260703a: SVOM/ECLAIRs Upper Limit
  28. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  29. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  30. GRB 260706A: ATCA detection of possible radio counterpart
  31. GRB 260705A: ATCA radio observations
  32. EP260713a: Einstein Probe detection of an X-ray transient
  33. EP260623a: KAIT optical observations
  34. GRB 260708A: GRANDMA Optical Observations
  35. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  36. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  37. GRB 260708A: LCO optical observations
  38. EP260711a: Einstein Probe detection of an X-ray transient
  39. GRB 260709A: SVOM/GRM detection
  40. GRB 260709A: GECAM-B observation
  41. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  42. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  43. GRB 260704A: SVOM/ECLAIRs refined analysis
  44. GRB 260706A : GRANDMA Upper limits
  45. GRB 260708A: Kilonova-Catcher optical afterglow detection
  46. IceCube-260708A: One candidate from the Zwicky Transient Facility
  47. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  48. GRB 260705B: SVOM/GRM observation
  49. EP260707a (by EP-FXT): NOT optical upper limit
  50. EP260707a is not a real source
  51. EP260707a: LCOGT Optical Upper Limit
  52. EP260707a: TRT optical upper limit
  53. EP260707a: Einstein Probe detection of an X-ray transient
  54. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  55. GRB 260706A: SVOM/ECLAIRs refined analysis
  56. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  57. GRB 260706A: REM optical/NIR observations
  58. GRB 260706A: LCO optical upper limit
  59. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  60. GRB 260705A: SVOM/ECLAIRs refined analysis
  61. GRB 260705A: LCO optical upper limits
  62. GRB 260704A: NOT optical upper limits
  63. GRB 260629A: SVOM/GRM observation of a short burst
  64. GRB 260629A: AstroSat CZTI detection
  65. GRB 260704A: SVOM detection of a possible GRB
  66. EP260703a: EP-WXT detection of a fast X-ray transient
  67. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  68. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  69. EP260628a: EP-WXT detection of a fast X-ray transient
  70. EP260626a: further Liverpool Telescope optical upper limits
  71. EP260626a: COLIBRÍ optical upper limit
  72. EP260626a: Liverpool Telescope upper limits
  73. EP260626a: EP-WXT detection of a fast X-ray transient
  74. EP260623a: TNG NIR afterglow detection
  75. MASS-Cube (GRID 2.0) detection of GRB 260616B
  76. GRB 260619A: SVOM/ECLAIRs refined analysis
  77. EP260623a: Liverpool Telescope optical observations
  78. Konus-Wind detection of GRB 260618B
  79. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  80. EP260623a: WINTER J-band observations
  81. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  82. EP260623a: Optical follow-up observations with Kinder
  83. EP260623a: SVOM/VT optical observations
  84. EP260623a: TRT optical observations
  85. EP260623a: REM optical/NIR afterglow detection
  86. EP 260623a: COLIBRÍ optical observations
  87. EP260623a: Las Cumbres discovery of the optical counterpart
  88. EP260623a: Einstein Probe detection of an X-ray transient
  89. GRB 260614B: EP-FXT follow-up observation
  90. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  91. EP260618a: Liverpool Telescope optical observations
  92. GRB 260618B: LCO optical observations
  93. EP260618a: JinShan optical observations
  94. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  95. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  96. GRB 260619A: TRT optical counterpart confirmation
  97. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  98. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  99. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  100. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate

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