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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

41996 results found.

  1. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  2. GRB 260310A / AT2026fgk: X-ray rebrightening
  3. EP260402a / GRB 260402A: Mephisto optical upper limits
  4. EP-WXT01709259586: Xinglong optical upper limit
  5. EP260403a: Mephisto optical upper limits
  6. EP260402a/GRB 260402A: Xinglong optical upper limit
  7. EP260321a: Upper limits from VLA radio observations
  8. GRID detection of GRB 260401A
  9. EP260321a: uGMRT observations
  10. EP260405a: GMOS-N optical upper limits
  11. EP260405a: SVOM/VT optical upper limits
  12. EP260405a: Global MASTER-Net observations report
  13. EP260405a: Einstein Probe detection of a fast X-ray transient
  14. The EP-WXT trigger 01709259621 is likely a flaring star
  15. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  16. The EP-WXT trigger 01709259615 is likely a flaring star
  17. Fermi trigger No 797039833: Global MASTER-Net observations report
  18. GRB 260403A: GECAM-B observation of a long burst
  19. EP260324A / AT 2026hir: COLIBRÍ further optical observations
  20. Fermi Gamma-ray Burst Monitor trigger 796972356/260404217 is not a GRB
  21. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  22. The EP-WXT trigger 01709259586 is likely a flaring star
  23. GRB 260330B: SVOM/VT further optical observation
  24. Fermi Gamma-ray Burst Monitor trigger 796931884/260403749 is not a GRB
  25. GRB 260330B: SVOM/ECLAIRs refined analysis
  26. EP260403a: LCO optical observations of the counterpart
  27. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  28. EP260403a: LCO optical counterpart detection
  29. EP260403a: COLIBRÍ optical counterpart candidate
  30. GRB 260330B: SVOM/VT optical candidate
  31. EP260403a: Einstein Probe detection of an X-ray transient
  32. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow
  33. GRB 260403A: AstroSat CZTI detection
  34. EP260402a/GRB 260402A: refined analysis of the EP-WXT and EP-FXT observations
  35. GRB 260402B: GECAM-B observation
  36. EP260402a/GRB 260402A: Jinshan near-infrared upper limit
  37. GRB 260402C: NuSTAR detection of prompt emission
  38. GRB 260402C: AstroSat CZTI detection of a long burst
  39. EP260324A / AT 2026hir: COLIBRÍ optical observations
  40. EP260324A / AT 2026hir: Spectroscopic Observations with the Next Generation Palomar Spectrograph
  41. GRB 260402A: WINTER J-band upper limit
  42. GRB260402A: GROWTH-India Telescope optical upper limit
  43. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  44. EP260402a/GRB 260402A: SVOM/C-GFT upper limit
  45. GRB 260401A: SVOM/GRM observation
  46. GRB 260401A: GECAM-B observation
  47. EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient
  48. GRB 260402A: Kilonova-Catcher optical upper limit
  49. GRB 260402A: MASTER optical observations
  50. GRB 260402A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  51. GRB 260402A: SVOM/MXT candidate X-ray afterglow
  52. GRB 260402A: SVOM detection of a burst
  53. Fermi GRB 260401A: Global MASTER-Net observations report
  54. GRB 260401A: Fermi GBM Observation
  55. GRB 260401A: NuSTAR detection of prompt emission
  56. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  57. GRB 260401A: MAXI/GSC detection
  58. EP260329b: Mondy and Assy-Turgen optical upper limits
  59. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  60. EP260321a :Xinglong optical observations
  61. EP260327a: Xinglong optical upper limit
  62. EP260329b: GOTO detection of optical counterpart
  63. GRB 260330B: SVOM/VT optical upper limits
  64. Konus-Wind detection of GRB 260320A
  65. Konus-Wind detection of GRB 260316B (duplicate submission)
  66. Konus-Wind detection of GRB 260316B
  67. GRB 260321A: SVOM/ECLAIRs refined analysis
  68. EP260329b: J-band upper limits with WINTER
  69. EP260329a: J-band upper limit with WINTER
  70. GRB 260330A: Glowbug gamma-ray detection
  71. GRB 260310A: VLA Multi-frequency Radio Observations
  72. Fermi GBM Sub-Threshold Detection of GRB 260330B
  73. GRB 260330B: LCO optical upper limits
  74. GRB 260330B: SVOM detection of a burst
  75. EP260324a / AT2026hir: g- and r-band optical follow-up with the PKU 60cm Telescope
  76. EP260329b: refined analysis of the EP-WXT and EP-FXT observations
  77. EP260329a: COLIBRÍ optical upper limit
  78. EP260329a: EP-FXT follow up observation
  79. EP260329a: NOT optical counterpart candidate
  80. EP260329b: Global MASTER-Net observations report
  81. Fermi trigger No 796485221: Global MASTER-Net observations report
  82. GRB 260327A: Insight-HXMT/HE detection
  83. EP260329b: Optical follow-up with Kinder observations
  84. EP 260329b: COLIBRÍ optical observations
  85. EP260329a: Optical upper limit with Kinder observations
  86. EP260329b: LCO optical observations of the counterpart
  87. GRB 260326A: Insight-HXMT/HE detection
  88. EP260329b: Einstein Probe detection of an X-ray transient
  89. EP260329a: Einstein Probe detection of an X-ray transient
  90. EP-WXT trigger 01709259209: TRT optical counterpart detection
  91. The EP-WXT trigger 01709259209 (EP260329b?): Las Cumbres discovery of the optical counterpart
  92. GRID detection of GRB 260326A
  93. GRB 260310A: Gemini-North Spectral Confirmation of Supernova Features
  94. EP260327a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  95. EP260327a: SVOM/VT optical upper limits
  96. SMA Detection of GRB 260310A / AT 2026fgk
  97. GRB 260307B: ATCA Radio Upper Limits
  98. EP260327a: WINTER J-band upper limit
  99. EP260327a: COLIBRÍ optical upper limits
  100. GRB 260327A: AstroSat CZTI detection of a long burst

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