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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

2406 results found.

  1. GRB 260515A: SVOM/VT optical observations
  2. GRB 260515A: OHP/T193 optical observations
  3. GRB 260515A: LCO optical observations
  4. SVOM GRB 260515A: Global MASTER-Net observations report
  5. GRB 260515A: NOT optical observations.
  6. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  7. GRB 260515A: SVOM/VT optical candidate from VHF data
  8. GRB 260515A: JinShan optical counterpart candidate
  9. GRB 260515A: SVOM detection of a burst
  10. GRB 260510C: Glowbug gamma-ray detection
  11. GRB 260511B: NOT optical observations
  12. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  13. GRB 260511B: Mephisto multi-band optical followup
  14. GRB 260511B: further SAO RAS optical observations
  15. GRB 260509A: SVOM/VT optical observations
  16. Konus-Wind detection of GRB 260511B
  17. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  18. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  19. GRB 260511A: Glowbug gamma-ray detection
  20. Konus-Wind detection of GRB 260511A
  21. MASS-Cube (GRID 2.0) detection of GRB 260511A
  22. GRB 260511B: SAO RAS optical observations
  23. GRB 260511B: FRAM-ORM optical detection
  24. GRB 260511A: EP-FXT follow-up observation
  25. GRB 260511B: EP-FXT follow-up observation
  26. GRB 260511B: LCO optical counterpart detection
  27. GRB260511B: MAO/AZT-22 optical observations
  28. GRB 260511A: SVOM/VT optical observations
  29. GRB 260511B: LCO optical observations
  30. GRB 260511B: GOTO optical counterpart detection
  31. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  32. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  33. GRB 260511B: SVOM/VT optical observations
  34. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  35. GRB 260510B: EP-FXT follow-up observation
  36. GRB 260510C: Fermi GBM Observation
  37. GRB 260511A: REM near-infrared detection
  38. GRB 260511B: AstroSat CZTI detection
  39. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  40. GRB 260511B: NuSTAR detection of prompt emission
  41. GRB 260511A: NuSTAR detection of prompt emission
  42. GRB 260511B: Fermi GBM Detection
  43. GRB 260511B: SVOM/VT optical observation with VHF data
  44. GRB 260511B: TRT optical observation
  45. GRB 260510B: SVOM/ECLAIRs refined analysis
  46. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  47. GRB 260511A: Fermi GBM Detection
  48. GRB 260511B SVOM/C-GFT optical counterpart detection
  49. GRB 260511A: UTGO H50 optical afterglow observation
  50. GRB 260510C: AstroSat CZTI detection
  51. GRB 260511B: SVOM detection of a burst
  52. GRB 260510C: EP-FXT follow-up observation
  53. GRB 260510C: SVOM/VT optical counterpart confirmation
  54. GRB 260511A: SVOM/VT optical observation with VHF data
  55. GRB 260511A: KAIT optical afterglow observations
  56. GRB 260511A: LCO optical afterglow detection
  57. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  58. GRB 260511A: TRT optical counterpart detection
  59. GRB 260511A: SVOM detection of a bright burst
  60. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  61. GRB 260510B: SVOM/VT optical upper limits
  62. GRB 260510C: SVOM/VT optical upper limits
  63. GRB 260510C: MAXI/GSC detection
  64. Fermi GBM Sub-Threshold Detection of GRB 260510B
  65. GRB 260510B: GOTO early upper limit
  66. GRB 260510C: SVOM detection of a burst
  67. GRB 260510B: LCO optical upper limits
  68. GRB 260510B: SVOM detection of a burst
  69. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  70. GRB 260509A: LCO optical observations
  71. SVOM GRB 260509A: MASTER-OAFA optical observation
  72. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  73. GRB 260509A: SVOM/VT optical candidate with VHF data
  74. GRB 260509A: LCO optical counterpart detection
  75. GRB 260509A: GOTO optical counterpart candidate
  76. GRB 260509A: SVOM detection of a burst
  77. EP260507a: SVOM/VT optical observations
  78. GRB 260504B: AstroSat CZTI detection
  79. GRB 260504B: SVOM/ECLAIRs refined analysis
  80. GRB 260430B: Glowbug gamma-ray detection
  81. GRB 260504B: SVOM/VT optical upper limits
  82. GRB 260421B: radio observation with the VLA
  83. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  84. Konus-Wind detection of GRB 260504B (short/hard)
  85. GRB 260504B: GECAM-B detection
  86. GRB 260504C: SVOM/GRM observation of short GRB
  87. GRB 260504B: SVOM/GRM spectral analysis
  88. GRB 260504B: SVOM/MXT refined analysis and potential detection
  89. GRB 260502A: SVOM/GRM observation of a short GRB
  90. GRB 260503A: SVOM/GRM observation of a GRB
  91. GRB 260504B: REM optical/NIR observations
  92. IPN triangulation of GRB 260429A
  93. IPN triangulation of GRB 260428A
  94. GRB 260504B: AST3-2 i-band upper limit
  95. GRB 260504B: LCO z-band upper limit
  96. SVOM GRB 260504B: MASTER-OAFA optical observations
  97. GRB 260504B: SVOM detection of a short burst
  98. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  99. IPN triangulation of a bright burst from SGR 1E1841-045
  100. GRB 260429A: SVOM/GRM observation of a short burst

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