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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"
  1. Konus-Wind observation of GRB 180409A
  2. GRB 180410A: Swift detection of a burst or a Galactic transient.
  3. IPN Triangulation of GRB 180409A
  4. GRB 180409A: Tiled Swift observations
  5. GRB 180402A: ISON-NM early optical limits
  6. GRB 180407A: Swift-BAT refined analysis
  7. Swift Trigger 823014: TAROT Calern observatory optical observations
  8. GRB 180407A: COATLI Upper Limits
  9. Swift Trigger 823014 is probably not a GRB
  10. GRB 180407A: Swift detection of a burst
  11. GRB 180404B: Swift/UVOT Detection
  12. IPN Triangulation of GRB 180404C (long)
  13. Konus-Wind observation of GRB 180404B
  14. Chandra observations of GRB161219B 400 days after the explosion
  15. GRB 180404C CALET Gamma-Ray Burst Monitor detection
  16. Fermi GBM triggers 544628550/180405571, 544542853/180404579, 544531428/180404447 are not GRBs
  17. GRB 180404A: Swift/UVOT Detection
  18. GRB 180404A: LCO FTS observations
  19. GRB 180404A: Swift-XRT refined Analysis
  20. GRB 180404B: Swift-BAT refined analysis
  21. GRB 180402A: Fermi GBM refined spectral analysis
  22. GRB 180404A: Swift-BAT refined analysis
  23. GRB 180404B: Swift-XRT refined Analysis
  24. GRB 180404B: Fermi GBM observation
  25. GRB 180404B: MASTER-OAFA OT observation
  26. Fermi GBM triggers 544440014/180403389 and 544451446/180403521 are not GRBs
  27. GRB 180404B: Enhanced Swift-XRT position
  28. GRB 180404A: MASTER-OAFA OT observation
  29. GRB 180404A: Enhanced Swift-XRT position
  30. GRB 180404A: VLT/X-shooter redshift
  31. GRB 180404B: Swift detection of a burst with an optical counterpart
  32. GRB 180404A: Swift detection of a burst with an optical afterglow
  33. Konus-Wind observation of GRB 180402A
  34. GRB 180402A: Swift/UVOT Upper Limits
  35. GRB 180402A: Swift-XRT refined Analysis
  36. GRB 180402A: Fermi GBM detection
  37. GRB 180402A, Swift-BAT refined analysis
  38. GRB 180402A: KAIT Optical Upper Limit
  39. GRB 180402A: RATIR Upper Limits
  40. GRB 180402A: LCO McDonald observations
  41. GRB 180402A: Swift detection of a possibly short burst
  42. GRB 180331B: Swift/UVOT Upper Limits
  43. GRB 180331B: Swift-XRT refined Analysis
  44. GRB 180331B: AbAO optical observations
  45. GRB 180331B: Swift-BAT refined analysis
  46. GRB 180331B: Enhanced Swift-XRT position
  47. GRB 180331A: Swift-BAT refined analysis
  48. GRB 180331B: Swift detection of a burst
  49. GRB 180331A: Swift-XRT refined Analysis
  50. GRB 180329B: LCO FTS observations
  51. GRB 180331A: Swift/UVOT Upper Limits
  52. GRB 180331A: Enhanced Swift-XRT position
  53. GRB 180331A: Swift detection of a burst
  54. GRB 180329B: VLT/X-shooter spectroscopic observations
  55. GRB 180329B: Swift-BAT refined analysis
  56. GRB 180329B: Swift/UVOT Detection
  57. GRB 180329B: RATIR Optical Observations
  58. Swift Trigger 819863 is not a GRB
  59. GRB 180329B: NOT optical afterglow detection
  60. GRB 180329A: Swift-BAT refined analysis
  61. GRB 180329B: Swift-XRT refined Analysis
  62. GRB 180329B: Enhanced Swift-XRT position
  63. GRB 180329B: Swift detection of a burst with an optical afterglow
  64. GRB180325A: AstroSat CZTI detection
  65. Swift Trigger 819301: possible GRB 180329A
  66. GRB 180325A: VLT/X-shooter spectroscopic observations
  67. Konus-Wind observation of GRB 180318A
  68. Konus-Wind observation of GRB 180326A
  69. Konus-Wind observation of GRB 180317A
  70. GRB 180325A: further NOT observations
  71. IPN Triangulation of GRB 180326A (long)
  72. GRB 180325A: Swift/UVOT Detection
  73. Konus-Wind observation of GRB 180316A
  74. Konus-Wind observation of GRB 180324A
  75. Konus-Wind observation of GRB 180325A
  76. GRB 180325A, Swift-BAT refined analysis
  77. GRB 180325A: GROND observations
  78. GRB 180325A: Global MASTER-Net OT prompt observations
  79. GRB 180325A: TAROT Calern observatory optical observations
  80. GRB 180325A: D50 early optical follow-up
  81. GRB 180325A: Swift-XRT refined Analysis
  82. GRB 180325A: Enhanced Swift-XRT position
  83. GRB 180325A: Optical Photometry with SLKT
  84. GRB 180325A: RATIR Optical Observations
  85. GRB 180325A: prompt REM optical/NIR detection
  86. GRB 180325A: NOT redshift
  87. GRB 180325A: prompt LT observations
  88. GRB 180324A, Swift-BAT refined analysis
  89. GRB 180325A: Swift detection of a burst with an optical counterpart
  90. GRB 180324A: Swift/UVOT Upper Limits
  91. GRB 180324A: Swift-XRT refined Analysis
  92. GRB 180324A: Enhanced Swift-XRT position
  93. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  94. GRB 180324A: KAIT Optical Upper Limit
  95. GRB 180324A: Prompt enhanced Swift-XRT position
  96. GRB 180324A: Swift detection of a burst
  97. IBAS Alert n. 8033: Not a GRB
  98. IPN Triangulation of GRB 180318A (long)
  99. IPN Triangulation of GRB 180317A (short/hard)
  100. IBAS Alert n. 8032: Not a GRB

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