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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').
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"

21467 results found.

  1. GRB 240112C: Glowbug gamma-ray detection
  2. GRB 240112C: VZLUSAT-2 detection
  3. Konus-Wind detection of GRB 240112C
  4. GRB 240112C: GRBAlpha detection
  5. GRB 240112C: Swift/UVOT Detection
  6. GRB 240112C: Fermi GBM Detection
  7. GRB 240112C: Swift-XRT refined Analysis
  8. GRB 240112C: SAO RAS optical observations
  9. Swift GRB 240112C: Global MASTER-Net observations report
  10. GRB 240109A: Swift-BAT refined analysis
  11. GRB 240112C: Swift detection of a burst with an optical counterpart
  12. GRB 240109A: Fermi GBM Observation
  13. GRB 231214A: ATCA Radio Upper Limits
  14. Konus-Wind detection of GRB 240101C
  15. Swift GRB240109.17: Global MASTER-Net observations report
  16. GRB 240109A: Swift detection of a short burst
  17. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  18. IPN triangulation of GRB 240101C (short)
  19. GRB GRB240101C: Fermi GBM observation
  20. GRB 240101A: 1.3m DFOT optical observations
  21. GRB 240102A: 1.3m DFOT optical upper limit
  22. GRB 240101B: 1.3m DFOT optical upper limit
  23. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  24. GRB 231220A: Swift-UVOT upper limit
  25. GRB 240102A: Swift-BAT refined analysis
  26. GRB 240102A: Swift/UVOT Upper Limits
  27. GRB 231230A: Swift-BAT refined analysis
  28. GRB 240101A: Swift-BAT refined analysis
  29. GRB 240101B: Swift-BAT refined analysis
  30. GRB 240102A: Enhanced Swift-XRT position
  31. GRB 240101B: Swift-XRT refined Analysis
  32. GRB 240102A: Swift-XRT refined Analysis
  33. GRB 240102A: LCOGT Optical Upper Limits
  34. GRB240102A: BOOTES-6/DPRT optical upper limit
  35. GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  36. GRB 240102A: Swift detection of a burst
  37. GRB 240101A: Terskol Zeiss-2000 optical observations
  38. GRB 240101B: Swift/UVOT Upper Limits
  39. GRB 240101A: Swift/UVOT Upper Limits
  40. GRB 240101A: Swift-XRT refined Analysis
  41. GRB 240101B: Enhanced Swift-XRT position
  42. GRB 240101B: KAIT Optical Upper Limit
  43. GRB 240101A: KAIT Optical Upper Limit
  44. GRB 240101A: Enhanced Swift-XRT position
  45. Swift GRB240101.85: Global MASTER-Net observations report
  46. GRB 240101B: Swift detection of a burst
  47. GRB 240101A: Swift detection of a burst
  48. GRB231230A: Fermi GBM Observation
  49. GRB 231230A: Swift-XRT refined Analysis
  50. GRB 231230A: GOTO optical upper limits
  51. GRB 231230A: Enhanced Swift-XRT position
  52. GRB 231230A: Swift/UVOT Upper Limits
  53. GRB 231230A: NOT optical upper limits
  54. GRB 231230A: Prompt enhanced Swift-XRT position
  55. GRB 231230A: Swift detection of a burst
  56. Swift GRB231230.06: Global MASTER-Net observations report
  57. GRB 231210B: BOOTES-7 optical upper limit
  58. Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
  59. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  60. GRB 231222B: Swift-XRT afterglow detection
  61. GRB 231222B: Fermi-LAT detection
  62. GRB 231222A: Tiled Swift observations
  63. GRID detection of GRB 231215A
  64. GRB 231220A: Swift-XRT follow-up observations
  65. GRB 231220A: Swift ToO observations
  66. GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
  67. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  68. GRID detection of GRB 231205B
  69. GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
  70. GRB 231214B: Fermi GBM observation
  71. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  72. GRB 231216A: 10.4 m GTC optical upper limit
  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. Swift GRB231216.77: Global MASTER-Net observations report
  91. GRB 231216A: Swift detection of a burst
  92. Konus-Wind detection of GRB 231215A
  93. GRB 231215A: NOT optical observations
  94. GRB 231214A: Swift/UVOT Upper Limits
  95. GRB 231205B: VZLUSAT-2 detection
  96. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  97. GRB 231215A: Fermi GBM observation
  98. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  99. GRB 231215A: Swift/UVOT Detection
  100. GRB 231215A: Swift-XRT refined Analysis

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