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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"

39259 results found.

  1. GRB 260410A: Fermi GBM Final Real-time Localization
  2. EP260321a: Chandra X-ray Non-detection
  3. GRB 260409A: Fermi GBM Final Real-time Localization
  4. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  5. GRB 260407A: GECAM-A detection
  6. GRB 260407A: Insight-HXMT/HE detection
  7. EP260409a: COLIBRÍ optical upper limits
  8. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  9. EP260409a: Global MASTER-Net observations report
  10. GRB 260404A: Fermi GBM Final Localization
  11. GRB 260407A: Glowbug gamma-ray detection
  12. GRB 260402A: SVOM/ECLAIRs refined analysis
  13. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  14. GRB 260310A / AT2026fgk: X-ray rebrightening
  15. EP260402a / GRB 260402A: Mephisto optical upper limits
  16. EP260403a: Mephisto optical upper limits
  17. EP260402a/GRB 260402A: Xinglong optical upper limit
  18. GRID detection of GRB 260401A
  19. GRB 260407A: Fermi GBM Final Real-time Localization
  20. EP260405a: Global MASTER-Net observations report
  21. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  22. Fermi trigger No 797039833: Global MASTER-Net observations report
  23. GRB 260403A: GECAM-B observation of a long burst
  24. Fermi Gamma-ray Burst Monitor trigger 796972356/260404217 is not a GRB
  25. GRB 260330B: SVOM/VT further optical observation
  26. Fermi Gamma-ray Burst Monitor trigger 796931884/260403749 is not a GRB
  27. GRB 260330B: SVOM/ECLAIRs refined analysis
  28. EP260403a: LCO optical observations of the counterpart
  29. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  30. EP260403a: LCO optical counterpart detection
  31. EP260403a: COLIBRÍ optical counterpart candidate
  32. GRB 260330B: SVOM/VT optical candidate
  33. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow
  34. GRB 260403A: AstroSat CZTI detection
  35. EP260402a/GRB 260402A: refined analysis of the EP-WXT and EP-FXT observations
  36. GRB 260402B: GECAM-B observation
  37. EP260402a/GRB 260402A: Jinshan near-infrared upper limit
  38. GRB 260402C: NuSTAR detection of prompt emission
  39. GRB 260402C: AstroSat CZTI detection of a long burst
  40. EP260324A / AT 2026hir: COLIBRÍ optical observations
  41. GRB 260403A: Fermi GBM Final Real-time Localization
  42. GRB 260402B: Fermi GBM Final Real-time Localization
  43. GRB 260402A: WINTER J-band upper limit
  44. GRB260402A: GROWTH-India Telescope optical upper limit
  45. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  46. EP260402a/GRB 260402A: SVOM/C-GFT upper limit
  47. GRB 260401A: SVOM/GRM observation
  48. GRB 260401A: GECAM-B observation
  49. EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient
  50. GRB 260402A: Kilonova-Catcher optical upper limit
  51. GRB 260402A: MASTER optical observations
  52. GRB 260402A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  53. GRB 260402A: SVOM/MXT candidate X-ray afterglow
  54. GRB 260402A: SVOM detection of a burst
  55. Fermi GRB 260401A: Global MASTER-Net observations report
  56. GRB 260401A: Fermi GBM Observation
  57. GRB 260401A: NuSTAR detection of prompt emission
  58. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 260401A: MAXI/GSC detection
  60. GRB 260401A: BALROG localization (Fermi Trigger 796733611 / GRB 260401454)
  61. GRB 260401A: Fermi GBM Final Real-time Localization
  62. EP260329b: Mondy and Assy-Turgen optical upper limits
  63. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  64. EP260321a :Xinglong optical observations
  65. EP260329b: GOTO detection of optical counterpart
  66. GRB 260330B: SVOM/VT optical upper limits
  67. Konus-Wind detection of GRB 260320A
  68. Konus-Wind detection of GRB 260316B (duplicate submission)
  69. Konus-Wind detection of GRB 260316B
  70. GRB 260321A: SVOM/ECLAIRs refined analysis
  71. EP260329b: J-band upper limits with WINTER
  72. EP260329a: J-band upper limit with WINTER
  73. GRB 260330A: Glowbug gamma-ray detection
  74. GRB 260310A: VLA Multi-frequency Radio Observations
  75. Fermi GBM Sub-Threshold Detection of GRB 260330B
  76. GRB 260330B: LCO optical upper limits
  77. GRB 260330B: SVOM detection of a burst
  78. EP260329a: COLIBRÍ optical upper limit
  79. GRB 260330A: Fermi GBM Final Real-time Localization
  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. EP 260329b: COLIBRÍ optical observations
  84. EP260329b: LCO optical observations of the counterpart
  85. GRB 260326A: Insight-HXMT/HE detection
  86. EP-WXT trigger 01709259209: TRT optical counterpart detection
  87. GRID detection of GRB 260326A
  88. GRB 260310A: Gemini-North Spectral Confirmation of Supernova Features
  89. SMA Detection of GRB 260310A / AT 2026fgk
  90. GRB 260307B: ATCA Radio Upper Limits
  91. EP260327a: COLIBRÍ optical upper limits
  92. GRB 260327A: AstroSat CZTI detection of a long burst
  93. EP260324a: GROWTH-India Telescope optical observation
  94. EP260327a: Global MASTER-Net observations report
  95. GRB 260310A / AT 2026fgk: COLIBRÍ photometric evidence of the emerging supernova
  96. GRB 260310A: OSIRIS+/GTC spectroscopic detection of the associated BL-Ic, SN 2026fgk
  97. GRB 260310A / AT2026fgk: Late-time infrared detection with MIRAGE on the MDM 1.3m telescope
  98. IPN triangulation of GRB 260320A
  99. GRB 260310A / AT2026fgk: R- and I-band observations with the PKU 60 cm optical telescope
  100. GRB 260326A: Fermi GBM Detection

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