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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"

26123 results found.

  1. IPN triangulation of GRB 250407A
  2. GRB 250407A: LCO detection of a fading optical counterpart
  3. EP250407a: Swift-XRT observations
  4. Konus-Wind detection of GRB 250407A
  5. GRB 250407A: SVOM/GRM observation of a bright long burst
  6. GRB 250407A: EP-WXT afterglow detection
  7. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  8. GRB 250407A: KAIT Optical Afterglow Candidate
  9. GRB 250407A: Fermi GBM Detection
  10. GRB 250407A: Swift-XRT afterglow detection
  11. GRB 250407A: Swift ToO observations
  12. GRB 250407A: SRG/ART-XC afterglow detection
  13. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  14. IPN triangulation of GRB 250406B (short/hard)
  15. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  16. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  17. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  18. GRB 250331D: Swift-XRT afterglow detection
  19. EP250404a: REM optical/NIR observations
  20. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  21. GRB 250403A: Montarrenti Observatory optical detection
  22. GRB 250403A: KAIT optical observations
  23. EP250404a: AKO Optical Afterglow Detection
  24. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  25. GRB 250331C Swift-BAT refined analysis
  26. GRB 250331B Swift-BAT refined analysis
  27. GRB 250330A Swift-BAT refined analysis
  28. EP250321A: J band upper limit by SYSU 80cm telescope
  29. EP250404a: BOOTES-4/JGT optical afterglow detection
  30. GRB 250403A: Swift/UVOT Detection
  31. GRB 250402A: Swift/UVOT Upper Limits
  32. GRB 250403A: SVOM/VT optical observation
  33. GRB 250403A: REM NIR afterglow detection
  34. GRB 250403A: LCO optical counterpart detection
  35. GRB 250403A: JinShan optical observations
  36. GRB 250402A: EP-FXT afterglow detection
  37. GRB 250403A: Swift-XRT observations
  38. GRB 250322A: 10 GHz VLA radio upper limits
  39. GRB 250403A: GOTO detection of the optical afterglow
  40. GRB 250402A: Swift-XRT observations
  41. GRB 250225B: VLT host galaxy redshift z = 0.950
  42. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  43. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  44. GRB 250402A: REM optical/NIR upper limits
  45. GRB 250402A: refined SVOM/MXT data analysis
  46. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  47. GRB 250329B: Swift/UVOT Upper Limit
  48. GRB 250329A: Swift/UVOT Upper Limit
  49. GRB 250327B: Swift/UVOT Detection
  50. GRB 250327A: Swift/UVOT Upper Limits
  51. GRB 250327B: Kilonova-Catcher Observations
  52. GRB250331D: AbAO optical observations
  53. GRB 250331D: Fermi GBM observation
  54. GRB 250331C: Swift/UVOT Upper Limits
  55. GRB 250331B: Swift/UVOT Upper Limits
  56. GRB 250328A: AbAO AS-32 Optical Observations
  57. GRB 250219A: NOT candidate host galaxy detection
  58. GRB 250331D: Swift-XRT observations
  59. GRB 250331C: Swift-XRT refined Analysis
  60. GRB 250331B: Swift-XRT refined Analysis
  61. GRB 250331B: Swift-XRT refined Analysis
  62. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  63. GRB 250327A Swift-BAT refined analysis
  64. GRB 250329B: CAHA 2.2m telescope optical limit
  65. GRB 250331D: Swift ToO observations
  66. Swift GRB 250331C: Global MASTER-Net observations report
  67. Swift GRB 250331B: Global MASTER-Net observations report
  68. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  69. GRB 250331C: Enhanced Swift-XRT position
  70. GRB 250331B: Enhanced Swift-XRT position
  71. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  72. GRB 250329B: Swift-XRT confirmation of fading
  73. GRB 250330A: VLT/FORS2 Afterglow Detection
  74. GRB20250327B: 45th Parallel Observatory upper limit
  75. GRB 250328A: Swift/UVOT Detection
  76. GRB 250328A: Swift-XRT refined Analysis
  77. GRB 250330A: Fermi GBM Observation
  78. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  79. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  80. GRB 250331C: Prompt enhanced Swift-XRT position
  81. GRB 250331C: Swift detection of a burst
  82. GRB 250331B: Swift detection of a burst
  83. GRB 250330A: SVOM/VT optical upper limit
  84. GRB 250330A: BOOTES-7 early optical upper limit
  85. GRB 250330A: Swift/UVOT Upper Limits
  86. GRB 250330A: Swift-XRT afterglow detection
  87. GRB 250328A: 1.6m Mephisto optical observations
  88. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  89. GRB 250330A: Fermi GBM Final Localization
  90. GRB 250330A: VLT/FORS2 Optical Observations
  91. GRB 250330A: Prompt Swift-XRT position
  92. GRB 250329B: Swift-XRT afterglow detection
  93. GRB 250330A: Swift detection of a burst
  94. Swift GRB250330.26: Global MASTER-Net observations report
  95. GRB 250328A: A fading optical afterglow confirmed by SVOM/VT
  96. GRB 250329B: SVOM/C-GFT optical upper limit
  97. GRB 250329B: SVOM/VT optical upper limit
  98. GRB250329A: REM optical afterglow detection
  99. GRB 250329A: Swift-XRT afterglow detection
  100. GRB 250328A: SVOM/C-GFT optical upper limit

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