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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').

18047 results found.

  1. GRB 250213A: Swift ToO observations
  2. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  3. GRB 250211A: Swift ToO observations
  4. GRB 250207A: Fermi GBM Observation
  5. Konus-Wind detection of GRB 250207A
  6. GRB 250207A: Skynet optical afterglow observations
  7. GRB 250207A: 1.3m DFOT Optical observations
  8. GRB 250206A: Swift-XRT observations
  9. GRB 250129A: GRANDMA Continued Afterglow Detection
  10. GRB 250207A: Swift-BAT refined analysis
  11. GRB 250205A: 1.3m DFOT optical upper limit
  12. GRB 250206A: Tiled Swift observations
  13. GRB 250206A: Fermi-LAT detection
  14. GRB 250207B: Swift-XRT observations
  15. EP250207a: EP-WXT detection and XRT follow-up observation
  16. GRB 250207A: Swift-XRT refined Analysis
  17. GRB 250207A: Enhanced Swift-XRT position
  18. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  19. GRB 250207A: REM IR afterglow detection
  20. GRB 250207A: FRAM-Auger optical detection
  21. GRB 250207B: Tiled Swift observations
  22. GRB 250207A: REM optical afterglow detection
  23. GRB 250207A: Swift/UVOT Detection
  24. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  25. GRB 250207A: Swift detection of a burst with optical counterpart
  26. GRB 250205A: Fermi GBM Observation
  27. GRB 250205A: Swift/UVOT Upper Limits
  28. GRB 250205A: Swift/XRT detection
  29. IPN triangulation of GRB 250201A
  30. GRB 250129A: Swift-BAT refined analysis
  31. IPN triangulation of GRB 250204B (short/hard)
  32. IPN triangulation of GRB 250202B
  33. GRB 250129A: LCO late afterglow detection
  34. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  35. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  36. GRB 250129A: SVOM/C-GFT optical observations
  37. Swift GRB250129A: MASTER 4 days observations report
  38. Konus-Wind detection of GRB 250129A
  39. GRB 250129A: 1.3m DFOT Optical observations
  40. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  41. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  42. GRB 250129A: COLIBRÍ Optical Observations
  43. GRB 250129A: TNG NIR afterglow detection
  44. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  45. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  46. GRB 250128B: VLA radio upper limit
  47. Ep250125A: 1.3m DFOT optical upper limit
  48. GRB 250129A: Skynet optical observations
  49. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  50. GRB 250129A: Swift-XRT refined Analysis
  51. GRB 250128B: TNG optical upper limit
  52. GRB 250129A: Swift/UVOT Detection
  53. GRB 250127A: CrAO and Terskol optical upper limits
  54. GRB 250129A: Enhanced Swift-XRT position
  55. GRB 250128B: NOT optical upper limit
  56. GRB 250129A: REM optical/NIR afterglow detection
  57. GRB 250129A: Early afterglow detection by LCO.
  58. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  59. GRB 250129A: LCO optical observations
  60. GRB 250129A: GOTO optical observations show brightening afterglow
  61. Swift GRB 250129A: Global MASTER-Net observations report
  62. GRB 250128B: Enhanced Swift-XRT position
  63. GRB 250129A: Swift detection of a burst with an optical counterpart
  64. Swift GRB 250129A: Global MASTER-Net OT detection
  65. GRB 250128B: Swift-XRT refined Analysis
  66. GRB 250128B: Fermi GBM Observation
  67. GRB 250128B: GOTO optical upper limit
  68. Swift GRB 250128B: Global MASTER-Net observations report
  69. EP250125a: Upper limits from Swift/BAT-GUANO
  70. GRB 250128B: LCO optical observations
  71. GRB 250128B: Swift detection of a short burst
  72. GRB 250127A: Swift-XRT observations
  73. GRB 250127A: EP-FXT afterglow detection
  74. GRB 250117A: Fermi GBM Observation
  75. GRB 250127A: SVOM/VT upper limit
  76. IPN triangulation of GRB 250119C
  77. GRB 250127A: Swift ToO observations
  78. GRB 250118A: Fermi GBM Observation
  79. EP250125a: REM optical counterpart detection
  80. GRB 250119C: Fermi GBM Observation
  81. EP250125a: Swift/XRT detection of a fading counterpart
  82. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  83. IPN triangulation of GRB 250118B
  84. Konus-Wind detection of GRB 250119B
  85. IPN triangulation of GRB 250119B
  86. Improved IPN triangulation of GRB 250107C
  87. GRB 250114A: Swift-BAT refined analysis
  88. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  89. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  90. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  91. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  92. Konus-Wind detection of GRB 250117A
  93. IPN triangulation of GRB 250117A (short)
  94. GRB 250117A: SVOM/GRM observation of a short burst
  95. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  96. Swift Trigger 1282245 is not a GRB
  97. GRB 250114B: Swift-XRT afterglow detection
  98. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  99. IPN triangulation of GRB 250113A
  100. GRB 250114B: Swift-XRT observations

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