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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

23413 results found.

  1. GRB 260718A: LCO optical upper limits
  2. GRB 260710A: SVOM/GRM observation
  3. GRB 260718A: Fermi GBM Observation
  4. GRB 260718A : GRANDMA and KNC upper limits
  5. GRB 260718A: SVOM/VT optical upper limits
  6. GRB 260718A: SVOM/VT optical upper limits from VHF data
  7. GRB 260714B: SVOM/GRM observation
  8. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  9. GRB 260714B: COLIBRÍ optical counterpart candidate
  10. sb26071506: SVOM detection of a X-ray transient
  11. EP260703a: SVOM/ECLAIRs Upper Limit
  12. GRB 260709A: AstroSat CZTI detection
  13. GRB 260714B: AstroSat CZTI detection
  14. GRB 260714B: Fermi GBM Detection
  15. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  16. EP260713a: Einstein Probe detection of an X-ray transient
  17. EP260623a: KAIT optical observations
  18. EP260711a: EP-FXT follow-up observation
  19. GRB 260708A: GRANDMA Optical Observations
  20. GRB 260708A: LCO optical observations
  21. EP260711a: Einstein Probe detection of an X-ray transient
  22. GRB 260710A: Fermi GBM Detection
  23. GRB 260709A: SVOM/GRM detection
  24. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  25. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  26. GRB 260708A: Glowbug gamma-ray detection
  27. GRB 260706A : GRANDMA Upper limits
  28. GRB 260708A: Kilonova-Catcher optical afterglow detection
  29. IceCube-260708A: One candidate from the Zwicky Transient Facility
  30. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  31. GRB 260705B: SVOM/GRM observation
  32. GRB 260706A: Further EP-FXT follow-up observation
  33. EP260707a (by EP-FXT): NOT optical upper limit
  34. EP260707a is not a real source
  35. EP260707a: LCOGT Optical Upper Limit
  36. EP260707a: TRT optical upper limit
  37. EP260707a: Einstein Probe detection of an X-ray transient
  38. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  39. GRB 260705C: Glowbug gamma-ray detection of a short burst
  40. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  41. GRB 260706A: REM optical/NIR observations
  42. GRB 260706A: LCO optical upper limit
  43. IPN triangulation of GRB 260627A
  44. IceCube260704A: OHP/T193 optical observations
  45. GRB 260705A: LCO optical upper limits
  46. GRB 260704A: NOT optical upper limits
  47. GRB 260629A: SVOM/GRM observation of a short burst
  48. GRB 260704A: SVOM detection of a possible GRB
  49. EP260703a: EP-WXT detection of a fast X-ray transient
  50. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  51. GRB 260623A: Glowbug gamma-ray detection
  52. GRB 260614B: ATCA Radio Upper Limits
  53. EP260628a: EP-WXT detection of a fast X-ray transient
  54. EP260626a: further Liverpool Telescope optical upper limits
  55. EP260626a: COLIBRÍ optical upper limit
  56. EP260626a: Liverpool Telescope upper limits
  57. EP260626a: EP-WXT detection of a fast X-ray transient
  58. EP260623a: TNG NIR afterglow detection
  59. EP260623a: Liverpool Telescope optical observations
  60. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  61. EP260623a: WINTER J-band observations
  62. GRB 260617A: Glowbug gamma-ray detection of a short burst
  63. IPN triangulation of GRB 260605A
  64. EP260623a: Optical follow-up observations with Kinder
  65. EP260623a: SVOM/VT optical observations
  66. EP260623a: TRT optical observations
  67. EP260623a: REM optical/NIR afterglow detection
  68. EP 260623a: COLIBRÍ optical observations
  69. EP260623a: Las Cumbres discovery of the optical counterpart
  70. EP260623a: Einstein Probe detection of an X-ray transient
  71. EP260618a: Liverpool Telescope optical observations
  72. GRB 260618B: LCO optical observations
  73. EP260618a: JinShan optical observations
  74. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  75. GRB 260619A: TRT optical counterpart confirmation
  76. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  77. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  78. Konus-Wind detection of GRB 260617A
  79. GRB 260616B: AstroSat CZTI detection
  80. GRB 260616A: AstroSat CZTI detection
  81. GRB 260616A: SVOM/GRM observation
  82. EP260618a: OHP/T193 optical observations
  83. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  84. GRB 260619A: Kilonova-Catcher optical upper limit
  85. EP260618a: EP-FXT follow-up observation
  86. EP260618a: LCO optical counterpart confirmation
  87. EP260618a: COLIBRÍ optical counterpart candidate
  88. GRB 260619A: SVOM possible detection of a faint burst
  89. IPN triangulation of GRB 260617A (short)
  90. EP260618a: EP-WXT detection of an X-ray transient
  91. GRB 260610B: AbAO optical observations
  92. GRB 260506B: cubesat Avion detection
  93. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  94. GRB 260616A: GECAM-B observation
  95. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  96. GRB 260429A: cubesat Avion detection
  97. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  98. GRB 260614A: AstroSat CZTI detection
  99. EP260616a: EP-WXT detection of a fast X-ray transient
  100. GRB 260610B: Terskol optical observations

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