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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

19670 results found.

  1. GRB 250219A: 1.6m Mephisto optical upper limits
  2. GRB 250219A: SVOM/VT optical counterpart
  3. GRB 250219A: Swift-XRT observations
  4. GRB 250219A: Swift ToO observations
  5. GRB 250217C: Swift-XRT observations
  6. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  7. GRB 250217C: Tiled Swift observations
  8. IPN triangulation of GRB 250217C (short)
  9. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  10. SVOM/sb25021804: SVOM detection of a long X-ray transient
  11. GRB 250213A: Swift-XRT observations
  12. GRB 250215A / EP250215a: LCO detection of the afterglow
  13. GRB 250215A: Swift/UVOT Upper Limits
  14. GRB 250215A: Fermi GBM Observation
  15. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  16. GRB 250215A: Swift-XRT refined Analysis
  17. GRB 250213A: Swift ToO observations
  18. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  19. GRB 250211A: Swift ToO observations
  20. GRB 250207A: Fermi GBM Observation
  21. Konus-Wind detection of GRB 250207A
  22. GRB 250207A: Skynet optical afterglow observations
  23. GRB 250207A: 1.3m DFOT Optical observations
  24. GRB 250206A: Swift-XRT observations
  25. GRB 250129A: GRANDMA Continued Afterglow Detection
  26. GRB 250207A: Swift-BAT refined analysis
  27. GRB 250205A: 1.3m DFOT optical upper limit
  28. GRB 250206A: Tiled Swift observations
  29. GRB 250206A: Fermi-LAT detection
  30. GRB 250207B: Swift-XRT observations
  31. EP250207a: EP-WXT detection and XRT follow-up observation
  32. GRB 250207A: Swift-XRT refined Analysis
  33. GRB 250207A: Enhanced Swift-XRT position
  34. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  35. GRB 250207A: REM IR afterglow detection
  36. GRB 250207A: FRAM-Auger optical detection
  37. GRB 250207B: Tiled Swift observations
  38. GRB 250207A: REM optical afterglow detection
  39. GRB 250207A: Swift/UVOT Detection
  40. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  41. GRB 250207A: Swift detection of a burst with optical counterpart
  42. GRB 250205A: Fermi GBM Observation
  43. GRB 250205A: Swift/UVOT Upper Limits
  44. GRB 250205A: Swift/XRT detection
  45. IPN triangulation of GRB 250201A
  46. GRB 250129A: Swift-BAT refined analysis
  47. IPN triangulation of GRB 250204B (short/hard)
  48. IPN triangulation of GRB 250202B
  49. GRB 250129A: LCO late afterglow detection
  50. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  51. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  52. GRB 250129A: SVOM/C-GFT optical observations
  53. Swift GRB250129A: MASTER 4 days observations report
  54. Konus-Wind detection of GRB 250129A
  55. GRB 250129A: 1.3m DFOT Optical observations
  56. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  57. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  58. GRB 250129A: COLIBRÍ Optical Observations
  59. GRB 250129A: TNG NIR afterglow detection
  60. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  61. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  62. GRB 250128B: VLA radio upper limit
  63. Ep250125A: 1.3m DFOT optical upper limit
  64. GRB 250129A: Skynet optical observations
  65. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  66. GRB 250129A: Swift-XRT refined Analysis
  67. GRB 250128B: TNG optical upper limit
  68. GRB 250129A: Swift/UVOT Detection
  69. GRB 250127A: CrAO and Terskol optical upper limits
  70. GRB 250129A: Enhanced Swift-XRT position
  71. GRB 250128B: NOT optical upper limit
  72. GRB 250129A: REM optical/NIR afterglow detection
  73. GRB 250129A: Early afterglow detection by LCO.
  74. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  75. GRB 250129A: LCO optical observations
  76. GRB 250129A: GOTO optical observations show brightening afterglow
  77. Swift GRB 250129A: Global MASTER-Net observations report
  78. GRB 250128B: Enhanced Swift-XRT position
  79. GRB 250129A: Swift detection of a burst with an optical counterpart
  80. Swift GRB 250129A: Global MASTER-Net OT detection
  81. GRB 250128B: Swift-XRT refined Analysis
  82. GRB 250128B: Fermi GBM Observation
  83. GRB 250128B: GOTO optical upper limit
  84. Swift GRB 250128B: Global MASTER-Net observations report
  85. EP250125a: Upper limits from Swift/BAT-GUANO
  86. GRB 250128B: LCO optical observations
  87. GRB 250128B: Swift detection of a short burst
  88. GRB 250127A: Swift-XRT observations
  89. GRB 250127A: EP-FXT afterglow detection
  90. GRB 250117A: Fermi GBM Observation
  91. GRB 250127A: SVOM/VT upper limit
  92. IPN triangulation of GRB 250119C
  93. GRB 250127A: Swift ToO observations
  94. GRB 250118A: Fermi GBM Observation
  95. EP250125a: REM optical counterpart detection
  96. GRB 250119C: Fermi GBM Observation
  97. EP250125a: Swift/XRT detection of a fading counterpart
  98. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  99. IPN triangulation of GRB 250118B
  100. Konus-Wind detection of GRB 250119B

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