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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"

37914 results found.

  1. GRB 250823A: LCOGT Optical Detection
  2. GRB 250823A: BOOTES6/DPRT early optical detection
  3. GRB 250823A: Liverpool Telescope optical detection
  4. GRB 250823A: Swift detection of a burst
  5. GRB 250823A: Fermi GBM Final Real-time Localization
  6. Swift GRB250823.84: Global MASTER-Net observations report
  7. Konus-Wind detection of GRB 250821B
  8. GRB 250806A: Gemini observations of host galaxy candidate
  9. IPN triangulation of GRB 250821B (long/bright)
  10. GRB 250821A: Kilonova-Catcher optical upper limits
  11. EP250821a: Swift/XRT counterpart fading
  12. GRB 250812A: SVOM/ECLAIRs refined analysis
  13. GRB 250821A: Swift-BAT refined analysis
  14. EP250821a: Swift/UVOT further observations.
  15. GRB 250821A: VLT/FORS2 Optical Observation
  16. GRB 250821A: GECAM-B detection
  17. GRB 250821B: SVOM/GRM observation
  18. EP250821a: SVOM/VT optical observation
  19. Fermi GRB 250821B: Global MASTER-Net observations report
  20. GRB 250821A: NOT z-band upper limit
  21. GRB 250821C: Fermi GBM Final Real-time Localization
  22. GRB 250821A: KAIT optical upper limit
  23. GRB 250821A: Swift-XRT refined Analysis
  24. Swift GRB 250821A: Global MASTER-Net observations report
  25. GRB 250821B: Fermi GBM Detection
  26. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  27. GRB 250821B: Fermi GBM Final Localization of a Bright Burst
  28. GRB 250821A: Enhanced Swift-XRT position
  29. GRB 250821A: Swift/UVOT Upper Limits
  30. EP250821a: Rapidly fading optical source detected in Las Cumbres followup
  31. EP250821a: Swift XRT and UVOT counterpart detection
  32. GRB 250821A: LCOGT Optical Upper Limits
  33. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  34. GRB 250821A: Prompt enhanced Swift-XRT position
  35. GRB 250821A: Swift detection of a burst
  36. GRB 250819A: SVOM/GRM observation of a possible “long” duration type I burst
  37. GRB 250819A: Insight-HXMT detection
  38. GRB 250818B: 10 GHz VLA detection
  39. LIGO/Virgo/KAGRA S250818k: Swift observations of AT 2025ulz
  40. GRB 250814A: Swift/UVOT Upper Limits
  41. GRB 250813B: Swift/UVOT Upper Limit
  42. IPN triangulation of GRB 250816A (short)
  43. IPN triangulation of GRB 250814C (short)
  44. IPN triangulation of GRB 250804B (short)
  45. GRB 250818B: FTW optical and NIR observations show reddening of the counterpart
  46. GRB 250818B: Kilonova-Catcher optical afterglow detection
  47. GRB 250818B: Liverpool Telescope optical detections
  48. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  49. GRB 250818A: AstroSat CZTI detection
  50. GRB 250818B: Swift/UVOT Detection
  51. Fermi Gamma-ray Burst Monitor trigger 777342746/250820022 is not a GRB
  52. GRB 250820A: Fermi GBM Final Real-time Localization
  53. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  54. GRB 250818B: TRT Optical Observation
  55. Fermi GRB 250816A: Global MASTER-Net observations report
  56. GRB 250818B: SAO RAS optical observations
  57. Swift GRB 250818A: Global MASTER-Net observations report
  58. GRB 250818B: NOT optical observations
  59. GRB 250818A: Swift-XRT refined Analysis
  60. GRB 250818B: EP-FXT counterpart detection
  61. GRB 250818A: Swift-BAT refined analysis
  62. Fermi Gamma-ray Burst Monitor trigger 777251788/250818970 is not a GRB
  63. GRB 250818C: Fermi GBM Final Real-time Localization
  64. GRB 250818B: Keck redshift of the optical afterglow
  65. GRB 250818B: KAIT optical observations
  66. GRB 250818A: Swift/UVOT Upper Limits
  67. GRB 250818A: Enhanced Swift-XRT position
  68. GRB 250813B: SVOM/ECLAIRs refined analysis
  69. GRB 250818A: Fermi GBM Observation
  70. GRB 250818B: SVOM/VT optical observation
  71. GRB 250814A: Further GRAWITA TNG NIR observations
  72. GRB 250818B: Swift-XRT afterglow detection
  73. GRB 250818B: GOTO optical counterpart candidate
  74. GRB 250818B: SVOM detection of a short burst
  75. GRB 250818A: Swift detection of a burst
  76. GRB 250818A: Fermi GBM Final Real-time Localization
  77. sb25081602: Swift-XRT observations
  78. GRB 250816A: SVOM/GRM observation of a short burst
  79. Fermi GRB 250814B: Global MASTER-Net observations report
  80. GRB 250816A: Fermi GBM Final Real-time Localization
  81. GRB 250814A: Swift-BAT refined analysis
  82. GRB 250815A: Fermi GBM Final Localization
  83. GRB 250813B: Liverpool Telescope optical upper limits
  84. GRB 250814A: Further COLIBRÍ optical upper limit
  85. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  86. GRB 250814A: GRAWITA TNG NIR observations
  87. GRB 250812A: SVOM/VT optical continued observation
  88. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  89. GRB 250813B: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  90. GRB250814A: TRT optical upper limits
  91. GRB 250814B: SVOM/GRM observation
  92. GRB 250814C: SVOM/GRM observation of a short burst
  93. LIGO/Virgo/KAGRA S250813k: Swift XRT observations, 2 X-ray sources
  94. GRB 250813B: SVOM/GRM observation
  95. GRB 250814A: P200/WIRC observations of the afterglow candidate
  96. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  97. GRB 250814A: KAIT optical upper limit
  98. GRB 250814A: Swift-XRT refined Analysis
  99. GRB 240814A: Fermi GBM Observation
  100. GRB 250814A: Possible afterglow candidate from P200/WIRC

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