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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 180316A: TSHAO optical observations
  2. GRB 180314A: AstroSat CZTI detection
  3. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  4. Konus-Wind observation of GRB 180314A
  5. GRB 180316A: Swift-BAT refined analysis
  6. GRB 180316A: Swift-XRT refined Analysis
  7. GRB 180316A: Swift/UVOT Detection
  8. GRB 180316A: RATIR Optical Observations
  9. GRB 180316A: Enhanced Swift-XRT position
  10. GRB 180316A: LCO Cerro Tololo observations
  11. GRB 180314A: MITSuME Okayama optical upper limits
  12. GROND observations of GRB 180316A
  13. GRB180316A: MASTER-IAC OT light curve
  14. GRB180316A: MASTER-IAC optical detection
  15. GRB 180316A: Prompt enhanced Swift-XRT position
  16. GRB 180316A: Swift detection of a burst
  17. GRB 180314B: RATIR Optical Observations
  18. GRB 180314B: Swift-BAT refined analysis
  19. GRB 180314B: Zeiss-1000/CrAO optical upper limit
  20. GRB 180314B: Swift/UVOT Upper Limits
  21. GRB 180314B: Swift-XRT refined Analysis
  22. GRB 180314B: Enhanced Swift-XRT position
  23. GRB 180313A: Fermi GBM detection
  24. GRB 180314B: Prompt enhanced Swift-XRT position
  25. GRB 180314B: Swift detection of a burst
  26. GRB 180314A: Swift-BAT refined analysis
  27. Swift Trigger on MAXI J1820+070
  28. GRB 180314A: TAROT La Silla observatory optical observations
  29. GRB 180314A: LCO Siding Springs observations
  30. GRB 180314A: Swift-XRT refined Analysis
  31. GRB 180314A: Fermi GBM observation
  32. GRB 180314A: VLT/X-shooter redshift
  33. GRB 180314A: Swift/UVOT Detection
  34. GRB 180314A: REM optical/NIR observations
  35. GRB 180314A: MASTER-Net OT dtetction
  36. GRB 180314A: Enhanced Swift-XRT position
  37. GRB180314A: GROND detection of the afterglow
  38. GRB 180314A: Swift detection of a burst with an optical counterpart
  39. Trigger 814090: Swift detection of MAXI J1820+070
  40. GRB 180305A: AstroSat CZTI detection
  41. GRB 180311A: Swift/UVOT Upper Limits
  42. GRB 180311A, Swift-BAT refined analysis
  43. GRB 180311A: Swift-XRT refined Analysis
  44. MAXI J1820+070: Swift/UVOT counterpart correction
  45. Swift detection of MAXI J1820+070
  46. GRB 180311A: Enhanced Swift-XRT position
  47. GRB 180311A: Prompt enhanced Swift-XRT position
  48. GRB 180311A: Swift detection of a burst
  49. GRB 180305A CALET Gamma-Ray Burst Monitor detection
  50. Trigger 813449: Swift detection of large burst from XTE J1701-407
  51. GRB 180305A: RATIR Optical Observations
  52. GRB 180305A: Swift/UVOT Upper Limits
  53. GRB 180305A: Mondy optical observations
  54. GRB 180305A: Swift-XRT afterglow detection
  55. Konus-Wind observation of GRB 180305A
  56. GRB 180305A: RATIR Optical Afterglow Candidate
  57. GRB 180305A: Swift ToO observations
  58. GRB 180305A: Fermi GBM detection
  59. GRB 180305A: Fermi-LAT detection
  60. GRB 180221B: Insight-HXMT/HE observation
  61. Fermi GBM trigger 541402602/180227234 is not a GRB
  62. GRB 180224A: Swift/UVOT Detection
  63. Konus-Wind observation of GRB 180223A
  64. GRB 180224A: OASDG optical observations
  65. IPN Triangulation of GRB 180223A (long)
  66. GRB 180210A: Insight-HXMT/HE observation
  67. Swift Trigger 811686 is probably not an astrophysical source.
  68. GRB 180224A: AbAO optical observations
  69. GRB 180224A: Swift-BAT refined analysis
  70. GRB 180224A: RATIR Optical Observations
  71. GRB 180224A: Swift-XRT refined Analysis
  72. GRB180224A: Global MASTER-Net bright OT detection
  73. GRB 180224A: Enhanced Swift-XRT position
  74. GRB 180224A: Swift detection of a burst with an optical counterpart
  75. GRB 180218A: AstroSat CZTI detection
  76. MAXI J1813-095 source: AbAO optical observations
  77. GRB 180222A: Swift/UVOT Upper Limits
  78. GRB 180221B CALET Gamma-Ray Burst Monitor detection
  79. GRB 180222A: Swift-XRT refined Analysis
  80. GRB 180222A: Swift-BAT refined analysis
  81. GRB 180222A: Enhanced Swift-XRT position
  82. GRB 180222A: A long GRB detected by INTEGRAL
  83. GRB 180222A: Swift detection of a burst
  84. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  85. Swift Trigger 811167: Detection of MAXI J1813-095
  86. GRB 180205A: Mondy optical observations
  87. GRB 180219A CALET Gamma-Ray Burst Monitor detection
  88. GRB180221A: MASTER-OAFA optical observations
  89. Swift Trigger 811074: possible GRB 180221A
  90. Konus-Wind observation of GRB 180218A
  91. GRB 180218A CALET Gamma-Ray Burst Monitor detection
  92. GRB 180218A: Fermi GBM Detection
  93. IPN Triangulation of GRB 180218A (long/bright)
  94. GRB 180204A: 15 GHz upper limits from AMI
  95. GRB 180112A: AstroSat CZTI detection
  96. Fermi GBM triggers 540405116/180215689 and 540476225/180216512 are not a GRBs
  97. Swift J1658.2-4242: Swift BAT and XRT refined analysis
  98. Swift trigger 810300: MASTER-OAFA robotic report
  99. Swift J1658.2-4242 (trigger 810300): Swift-XRT position
  100. Swift Trigger 810300 is a probable new Galactic source: Swift J1658.2-4242

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