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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"

28120 results found.

  1. GRB 260412A: Fermi GBM Observation
  2. GRB 260411B: Fermi-LAT detection
  3. GRB 260411B: COLIBRÍ optical observations
  4. GRB 260410B: Fermi GBM Observation
  5. GRB260411B: 3.6m DOT optical observation
  6. GRB 260411A: SVOM/GRM observation
  7. GRB 260411B: SVOM/GRM observation of a long burst
  8. GRB 260409A: Insight-HXMT/HE detection
  9. GRB 260411B: Fermi GBM Detection
  10. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  11. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  12. GRB 260410A: COLIBRÍ optical upper limit
  13. EP-WXT01709259790: Optical Upper limits with kinder observations
  14. GRB 260410A: Fermi GBM Observation
  15. GRB 260410B: SVOM/GRM detection of a short faint burst
  16. EP-WXT01709259790: Xinglong optical upper limit
  17. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  18. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  19. EP260409a: COLIBRÍ optical upper limits
  20. EP260409a: Global MASTER-Net observations report
  21. EP260409a: Einstein Probe detection of an X-ray transient
  22. EP260321a: VLA radio detection
  23. GRB 260407A: Glowbug gamma-ray detection
  24. GRB 260402A: SVOM/ECLAIRs refined analysis
  25. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  26. EP260402a / GRB 260402A: Mephisto optical upper limits
  27. EP-WXT01709259586: Xinglong optical upper limit
  28. EP260403a: Mephisto optical upper limits
  29. EP260402a/GRB 260402A: Xinglong optical upper limit
  30. EP260405a: GMOS-N optical upper limits
  31. EP260405a: Global MASTER-Net observations report
  32. EP260405a: Einstein Probe detection of a fast X-ray transient
  33. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  34. Fermi trigger No 797039833: Global MASTER-Net observations report
  35. EP260324A / AT 2026hir: COLIBRÍ further optical observations
  36. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  37. The EP-WXT trigger 01709259586 is likely a flaring star
  38. GRB 260330B: SVOM/VT further optical observation
  39. EP260403a: LCO optical observations of the counterpart
  40. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  41. EP260403a: LCO optical counterpart detection
  42. EP260403a: COLIBRÍ optical counterpart candidate
  43. GRB 260330B: SVOM/VT optical candidate
  44. EP260403a: Einstein Probe detection of an X-ray transient
  45. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow
  46. EP260402a/GRB 260402A: refined analysis of the EP-WXT and EP-FXT observations
  47. EP260402a/GRB 260402A: Jinshan near-infrared upper limit
  48. GRB 260402C: NuSTAR detection of prompt emission
  49. GRB 260402C: AstroSat CZTI detection of a long burst
  50. EP260324A / AT 2026hir: COLIBRÍ optical observations
  51. GRB 260402A: WINTER J-band upper limit
  52. GRB260402A: GROWTH-India Telescope optical upper limit
  53. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  54. EP260402a/GRB 260402A: SVOM/C-GFT upper limit
  55. GRB 260401A: SVOM/GRM observation
  56. EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient
  57. GRB 260402A: Kilonova-Catcher optical upper limit
  58. GRB 260402A: MASTER optical observations
  59. GRB 260402A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  60. GRB 260402A: SVOM/MXT candidate X-ray afterglow
  61. GRB 260402A: SVOM detection of a burst
  62. Fermi GRB 260401A: Global MASTER-Net observations report
  63. GRB 260401A: Fermi GBM Observation
  64. GRB 260401A: NuSTAR detection of prompt emission
  65. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  66. GRB 260401A: MAXI/GSC detection
  67. GRB 260401A: BALROG localization (Fermi Trigger 796733611 / GRB 260401454)
  68. GRB 260401A: Fermi GBM Final Real-time Localization
  69. EP260329b: Mondy and Assy-Turgen optical upper limits
  70. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  71. EP260321a :Xinglong optical observations
  72. EP260327a: Xinglong optical upper limit
  73. GRB 260330B: SVOM/VT optical upper limits
  74. Konus-Wind detection of GRB 260320A
  75. GRB 260321A: SVOM/ECLAIRs refined analysis
  76. EP260329b: J-band upper limits with WINTER
  77. EP260329a: J-band upper limit with WINTER
  78. GRB 260330A: Glowbug gamma-ray detection
  79. Fermi GBM Sub-Threshold Detection of GRB 260330B
  80. GRB 260330B: LCO optical upper limits
  81. EP260324a / AT2026hir: g- and r-band optical follow-up with the PKU 60cm Telescope
  82. EP260329b: refined analysis of the EP-WXT and EP-FXT observations
  83. EP260329a: COLIBRÍ optical upper limit
  84. EP260329a: EP-FXT follow up observation
  85. EP260329a: NOT optical counterpart candidate
  86. EP260329b: Global MASTER-Net observations report
  87. Fermi trigger No 796485221: Global MASTER-Net observations report
  88. GRB 260327A: Insight-HXMT/HE detection
  89. EP260329b: Optical follow-up with Kinder observations
  90. EP 260329b: COLIBRÍ optical observations
  91. EP260329a: Optical upper limit with Kinder observations
  92. EP260329b: LCO optical observations of the counterpart
  93. GRB 260326A: Insight-HXMT/HE detection
  94. EP260329b: Einstein Probe detection of an X-ray transient
  95. EP260329a: Einstein Probe detection of an X-ray transient
  96. EP-WXT trigger 01709259209: TRT optical counterpart detection
  97. The EP-WXT trigger 01709259209 (EP260329b?): Las Cumbres discovery of the optical counterpart
  98. EP260327a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  99. EP260327a: SVOM/VT optical upper limits
  100. EP260327a: WINTER J-band upper limit

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