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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"

36349 results found.

  1. GRB 240106A: GRBAlpha detection
  2. GRB 240107A: MAXI/GSC detection
  3. GRB 240106B: Fermi GBM Final Real-time Localization
  4. GRB 240106A: Fermi GBM Final Real-time Localization
  5. IPN triangulation of GRB 240101C (short)
  6. GRB GRB240101C: Fermi GBM observation
  7. GRB 240101A: 1.3m DFOT optical observations
  8. GRB 240102A: 1.3m DFOT optical upper limit
  9. GRB 240101B: 1.3m DFOT optical upper limit
  10. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  11. GRB 240102C: AstroSat CZTI detection
  12. GRB 240101C: AstroSat CZTI detection
  13. GRB 231220A: Swift-UVOT upper limit
  14. GRB 240102A: Swift-BAT refined analysis
  15. GRB 240102A: Swift/UVOT Upper Limits
  16. GRB 231230A: Swift-BAT refined analysis
  17. GRB 240101A: Swift-BAT refined analysis
  18. GRB 240101B: Swift-BAT refined analysis
  19. GRB 240102A: Enhanced Swift-XRT position
  20. GRB 240101B: Swift-XRT refined Analysis
  21. GRB 240102A: Swift-XRT refined Analysis
  22. GRB 240102B (Fermi GBM trigger 725926335/240102925) is not a GRB
  23. GRB 240102A: LCOGT Optical Upper Limits
  24. GRB240102A: BOOTES-6/DPRT optical upper limit
  25. GRB 240102B: Fermi GBM Final Real-time Localization
  26. GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  27. GRB 240102A: Swift detection of a burst
  28. GRB 240101A: Terskol Zeiss-2000 optical observations
  29. GRB 240101C: GRBAlpha detection
  30. GRB 240101B: Swift/UVOT Upper Limits
  31. GRB 240101A: Swift/UVOT Upper Limits
  32. GRB 240101A: Swift-XRT refined Analysis
  33. GRB 240101B: Enhanced Swift-XRT position
  34. GRB 240101B: KAIT Optical Upper Limit
  35. GRB 240101A: KAIT Optical Upper Limit
  36. GRB 240101A: Enhanced Swift-XRT position
  37. GRB 240101C: Fermi GBM Final Localization
  38. GRB 240101B: Swift detection of a burst
  39. GRB 240101A: Swift detection of a burst
  40. GRB231230A: Fermi GBM Observation
  41. GRB 231230A: Swift-XRT refined Analysis
  42. GRB 231230A: GOTO optical upper limits
  43. GRB 231230A: Enhanced Swift-XRT position
  44. GRB 231230A: Swift/UVOT Upper Limits
  45. GRB 231230A: NOT optical upper limits
  46. GRB 231230A: Prompt enhanced Swift-XRT position
  47. GRB 231230A: Swift detection of a burst
  48. GRB 231230A: Fermi GBM Final Real-time Localization
  49. GRB 231210B: BOOTES-7 optical upper limit
  50. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  51. IPN triangulation of GRB 231224A (short)
  52. GRB 231224A: Fermi GBM Final Real-time Localization
  53. GRB 231222B: GRBAlpha detection
  54. GRB 231222B: Swift-XRT afterglow detection
  55. GRB 231222B: Fermi GBM Detection
  56. GRB 231222B: Fermi-LAT detection
  57. GRB 231222A: Tiled Swift observations
  58. GRID detection of GRB 231215A
  59. GRB 231222A: Fermi GBM Final Real-time Localization
  60. GRB 231220A: Swift-XRT follow-up observations
  61. GRB 231220A: Swift ToO observations
  62. GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
  63. GRB 231220A: Fermi GBM Final Real-time Localization
  64. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  65. GRB 231219A: Fermi GBM Final Real-time Localization
  66. GRID detection of GRB 231205B
  67. GRID detection of GRB 231205A
  68. GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
  69. GRB 231214B: Fermi GBM observation
  70. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  71. GRB 231216A: 10.4 m GTC optical upper limit
  72. GRB 231215A: AMI-LA radio detection
  73. GRB 231216A: Nanshan/HMT optical upper limit
  74. GRB 231216A: LCOGT Optical Upper Limits
  75. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  76. GRB 231216A: Swift-XRT refined analysis correction
  77. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  78. GRB 231216A: Swift-XRT refined Analysis
  79. GRB 231216A: AST3-3 YaoAn Optical Upper Limit
  80. GRB 231216A: REM NIR upper limits
  81. GRB 231216A: Swift/UVOT Upper Limits
  82. GRB 231216A: Swift-BAT refined analysis
  83. GRB 231215A: Swift-BAT refined analysis
  84. GRB 231214A: Swift-BAT refined analysis
  85. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  86. GRB 231216A: GIT optical upper limit
  87. GRB 231216A: NOT optical upper limits
  88. GRB 231216A: BOOTES-2/TELMA optical upper limit
  89. GRB 231215A: GRBAlpha detection
  90. GRB 231216A: Swift detection of a burst
  91. Konus-Wind detection of GRB 231215A
  92. GRB 231215A: optical afterglow detection from the INAF Asiago Observatory
  93. GRB 231215A: NOT optical observations
  94. GRB 231214A: Swift/UVOT Upper Limits
  95. GRB 231215A: Redshift from OSIRIS+ / GTC
  96. GRB 231205B: VZLUSAT-2 detection
  97. GRB 231204A: VZLUSAT-2 detection
  98. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  99. GRB 231215A: Fermi GBM observation
  100. GRB 231215A: CALET Gamma-Ray Burst Monitor detection

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