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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"

28111 results found.

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

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