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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. GRB 180404A: Swift-XRT refined Analysis
  2. GRB 180404B: Swift-BAT refined analysis
  3. GRB 180402A: Fermi GBM refined spectral analysis
  4. GRB 180404A: Swift-BAT refined analysis
  5. GRB 180404B: Swift-XRT refined Analysis
  6. GRB 180404B: Fermi GBM observation
  7. GRB 180404B: MASTER-OAFA OT observation
  8. Fermi GBM triggers 544440014/180403389 and 544451446/180403521 are not GRBs
  9. GRB 180404B: Enhanced Swift-XRT position
  10. GRB 180404A: MASTER-OAFA OT observation
  11. GRB 180404A: Enhanced Swift-XRT position
  12. GRB 180404A: VLT/X-shooter redshift
  13. GRB 180404B: Swift detection of a burst with an optical counterpart
  14. GRB 180404A: Swift detection of a burst with an optical afterglow
  15. Konus-Wind observation of GRB 180402A
  16. GRB 180402A: Swift/UVOT Upper Limits
  17. GRB 180402A: Swift-XRT refined Analysis
  18. GRB 180402A: Fermi GBM detection
  19. GRB 180402A, Swift-BAT refined analysis
  20. GRB 180402A: KAIT Optical Upper Limit
  21. GRB 180402A: RATIR Upper Limits
  22. GRB 180402A: LCO McDonald observations
  23. GRB 180402A: Swift detection of a possibly short burst
  24. GRB 180331B: Swift/UVOT Upper Limits
  25. GRB 180331B: Swift-XRT refined Analysis
  26. GRB 180331B: AbAO optical observations
  27. GRB 180331B: Swift-BAT refined analysis
  28. GRB 180331B: Enhanced Swift-XRT position
  29. GRB 180331A: Swift-BAT refined analysis
  30. GRB 180331B: Swift detection of a burst
  31. GRB 180331A: Swift-XRT refined Analysis
  32. GRB 180329B: LCO FTS observations
  33. GRB 180331A: Swift/UVOT Upper Limits
  34. GRB 180331A: Enhanced Swift-XRT position
  35. GRB 180331A: Swift detection of a burst
  36. GRB 180329B: VLT/X-shooter spectroscopic observations
  37. GRB 180329B: Swift-BAT refined analysis
  38. GRB 180329B: Swift/UVOT Detection
  39. GRB 180329B: RATIR Optical Observations
  40. Swift Trigger 819863 is not a GRB
  41. GRB 180329B: NOT optical afterglow detection
  42. GRB 180329A: Swift-BAT refined analysis
  43. GRB 180329B: Swift-XRT refined Analysis
  44. GRB 180329B: Enhanced Swift-XRT position
  45. GRB 180329B: Swift detection of a burst with an optical afterglow
  46. GRB180325A: AstroSat CZTI detection
  47. Swift Trigger 819301: possible GRB 180329A
  48. GRB 180325A: VLT/X-shooter spectroscopic observations
  49. Konus-Wind observation of GRB 180318A
  50. Konus-Wind observation of GRB 180326A
  51. Konus-Wind observation of GRB 180317A
  52. GRB 180325A: further NOT observations
  53. IPN Triangulation of GRB 180326A (long)
  54. GRB 180325A: Swift/UVOT Detection
  55. Konus-Wind observation of GRB 180316A
  56. Konus-Wind observation of GRB 180324A
  57. Konus-Wind observation of GRB 180325A
  58. GRB 180325A, Swift-BAT refined analysis
  59. GRB 180325A: GROND observations
  60. GRB 180325A: Global MASTER-Net OT prompt observations
  61. GRB 180325A: TAROT Calern observatory optical observations
  62. GRB 180325A: D50 early optical follow-up
  63. GRB 180325A: Swift-XRT refined Analysis
  64. GRB 180325A: Enhanced Swift-XRT position
  65. GRB 180325A: Optical Photometry with SLKT
  66. GRB 180325A: RATIR Optical Observations
  67. GRB 180325A: prompt REM optical/NIR detection
  68. GRB 180325A: NOT redshift
  69. GRB 180325A: prompt LT observations
  70. GRB 180324A, Swift-BAT refined analysis
  71. GRB 180325A: Swift detection of a burst with an optical counterpart
  72. GRB 180324A: Swift/UVOT Upper Limits
  73. GRB 180324A: Swift-XRT refined Analysis
  74. GRB 180324A: Enhanced Swift-XRT position
  75. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  76. GRB 180324A: KAIT Optical Upper Limit
  77. GRB 180324A: Prompt enhanced Swift-XRT position
  78. GRB 180324A: Swift detection of a burst
  79. IBAS Alert n. 8033: Not a GRB
  80. IPN Triangulation of GRB 180318A (long)
  81. IPN Triangulation of GRB 180317A (short/hard)
  82. IBAS Alert n. 8032: Not a GRB
  83. GRB 180316A: RATIR Optical Observations
  84. GRB 180316A: MITSuME Akeno optical upper limits
  85. GRB 180316A: MITSuME Okayama optical upper limits
  86. GRB 180316A: TSHAO optical observations
  87. GRB 180314A: AstroSat CZTI detection
  88. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  89. Konus-Wind observation of GRB 180314A
  90. GRB 180316A: Swift-BAT refined analysis
  91. GRB 180316A: Swift-XRT refined Analysis
  92. GRB 180316A: Swift/UVOT Detection
  93. GRB 180316A: RATIR Optical Observations
  94. GRB 180316A: Enhanced Swift-XRT position
  95. GRB 180316A: LCO Cerro Tololo observations
  96. GRB 180314A: MITSuME Okayama optical upper limits
  97. GROND observations of GRB 180316A
  98. GRB180316A: MASTER-IAC OT light curve
  99. GRB180316A: MASTER-IAC optical detection
  100. GRB 180316A: Prompt enhanced Swift-XRT position

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