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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').
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.

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

28115 results found.

  1. GRB 260411B: Fermi-LAT detection
  2. GRB 260411B: COLIBRÍ optical observations
  3. GRB 260410B: Fermi GBM Observation
  4. GRB260411B: 3.6m DOT optical observation
  5. GRB 260411A: SVOM/GRM observation
  6. GRB 260411B: SVOM/GRM observation of a long burst
  7. GRB 260409A: Insight-HXMT/HE detection
  8. GRB 260411B: Fermi GBM Detection
  9. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  10. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  11. GRB 260410A: COLIBRÍ optical upper limit
  12. EP-WXT01709259790: Optical Upper limits with kinder observations
  13. GRB 260410A: Fermi GBM Observation
  14. GRB 260410B: SVOM/GRM detection of a short faint burst
  15. EP-WXT01709259790: Xinglong optical upper limit
  16. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  17. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  18. EP260409a: COLIBRÍ optical upper limits
  19. EP260409a: Global MASTER-Net observations report
  20. EP260409a: Einstein Probe detection of an X-ray transient
  21. EP260321a: VLA radio detection
  22. GRB 260407A: Glowbug gamma-ray detection
  23. GRB 260402A: SVOM/ECLAIRs refined analysis
  24. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  25. EP260402a / GRB 260402A: Mephisto optical upper limits
  26. EP-WXT01709259586: Xinglong optical upper limit
  27. EP260403a: Mephisto optical upper limits
  28. EP260402a/GRB 260402A: Xinglong optical upper limit
  29. EP260405a: GMOS-N optical upper limits
  30. EP260405a: Global MASTER-Net observations report
  31. EP260405a: Einstein Probe detection of a fast X-ray transient
  32. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  33. Fermi trigger No 797039833: Global MASTER-Net observations report
  34. EP260324A / AT 2026hir: COLIBRÍ further optical observations
  35. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  36. The EP-WXT trigger 01709259586 is likely a flaring star
  37. GRB 260330B: SVOM/VT further optical observation
  38. EP260403a: LCO optical observations of the counterpart
  39. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  40. EP260403a: LCO optical counterpart detection
  41. EP260403a: COLIBRÍ optical counterpart candidate
  42. GRB 260330B: SVOM/VT optical candidate
  43. EP260403a: Einstein Probe detection of an X-ray transient
  44. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow
  45. EP260402a/GRB 260402A: refined analysis of the EP-WXT and EP-FXT observations
  46. EP260402a/GRB 260402A: Jinshan near-infrared upper limit
  47. GRB 260402C: NuSTAR detection of prompt emission
  48. GRB 260402C: AstroSat CZTI detection of a long burst
  49. EP260324A / AT 2026hir: COLIBRÍ optical observations
  50. GRB 260402A: WINTER J-band upper limit
  51. GRB260402A: GROWTH-India Telescope optical upper limit
  52. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  53. EP260402a/GRB 260402A: SVOM/C-GFT upper limit
  54. GRB 260401A: SVOM/GRM observation
  55. EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient
  56. GRB 260402A: Kilonova-Catcher optical upper limit
  57. GRB 260402A: MASTER optical observations
  58. GRB 260402A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  59. GRB 260402A: SVOM/MXT candidate X-ray afterglow
  60. GRB 260402A: SVOM detection of a burst
  61. Fermi GRB 260401A: Global MASTER-Net observations report
  62. GRB 260401A: Fermi GBM Observation
  63. GRB 260401A: NuSTAR detection of prompt emission
  64. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  65. GRB 260401A: MAXI/GSC detection
  66. GRB 260401A: BALROG localization (Fermi Trigger 796733611 / GRB 260401454)
  67. GRB 260401A: Fermi GBM Final Real-time Localization
  68. EP260329b: Mondy and Assy-Turgen optical upper limits
  69. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  70. EP260321a :Xinglong optical observations
  71. EP260327a: Xinglong optical upper limit
  72. GRB 260330B: SVOM/VT optical upper limits
  73. Konus-Wind detection of GRB 260320A
  74. GRB 260321A: SVOM/ECLAIRs refined analysis
  75. EP260329b: J-band upper limits with WINTER
  76. EP260329a: J-band upper limit with WINTER
  77. GRB 260330A: Glowbug gamma-ray detection
  78. Fermi GBM Sub-Threshold Detection of GRB 260330B
  79. GRB 260330B: LCO optical upper limits
  80. EP260324a / AT2026hir: g- and r-band optical follow-up with the PKU 60cm Telescope
  81. EP260329b: refined analysis of the EP-WXT and EP-FXT observations
  82. EP260329a: COLIBRÍ optical upper limit
  83. EP260329a: EP-FXT follow up observation
  84. EP260329a: NOT optical counterpart candidate
  85. EP260329b: Global MASTER-Net observations report
  86. Fermi trigger No 796485221: Global MASTER-Net observations report
  87. GRB 260327A: Insight-HXMT/HE detection
  88. EP260329b: Optical follow-up with Kinder observations
  89. EP 260329b: COLIBRÍ optical observations
  90. EP260329a: Optical upper limit with Kinder observations
  91. EP260329b: LCO optical observations of the counterpart
  92. GRB 260326A: Insight-HXMT/HE detection
  93. EP260329b: Einstein Probe detection of an X-ray transient
  94. EP260329a: Einstein Probe detection of an X-ray transient
  95. EP-WXT trigger 01709259209: TRT optical counterpart detection
  96. The EP-WXT trigger 01709259209 (EP260329b?): Las Cumbres discovery of the optical counterpart
  97. EP260327a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  98. EP260327a: SVOM/VT optical upper limits
  99. EP260327a: WINTER J-band upper limit
  100. EP260327a: COLIBRÍ optical upper limits

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