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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 180314A: LCO Siding Springs observations
  2. GRB 180314A: Swift-XRT refined Analysis
  3. GRB 180314A: Fermi GBM observation
  4. GRB 180314A: VLT/X-shooter redshift
  5. GRB 180314A: Swift/UVOT Detection
  6. GRB 180314A: REM optical/NIR observations
  7. GRB 180314A: MASTER-Net OT dtetction
  8. GRB 180314A: Enhanced Swift-XRT position
  9. GRB180314A: GROND detection of the afterglow
  10. GRB 180314A: Swift detection of a burst with an optical counterpart
  11. Trigger 814090: Swift detection of MAXI J1820+070
  12. GRB 180305A: AstroSat CZTI detection
  13. GRB 180311A: Swift/UVOT Upper Limits
  14. GRB 180311A, Swift-BAT refined analysis
  15. GRB 180311A: Swift-XRT refined Analysis
  16. MAXI J1820+070: Swift/UVOT counterpart correction
  17. Swift detection of MAXI J1820+070
  18. GRB 180311A: Enhanced Swift-XRT position
  19. GRB 180311A: Prompt enhanced Swift-XRT position
  20. GRB 180311A: Swift detection of a burst
  21. GRB 180305A CALET Gamma-Ray Burst Monitor detection
  22. Trigger 813449: Swift detection of large burst from XTE J1701-407
  23. GRB 180305A: RATIR Optical Observations
  24. GRB 180305A: Swift/UVOT Upper Limits
  25. GRB 180305A: Mondy optical observations
  26. GRB 180305A: Swift-XRT afterglow detection
  27. Konus-Wind observation of GRB 180305A
  28. GRB 180305A: RATIR Optical Afterglow Candidate
  29. GRB 180305A: Swift ToO observations
  30. GRB 180305A: Fermi GBM detection
  31. GRB 180305A: Fermi-LAT detection
  32. GRB 180221B: Insight-HXMT/HE observation
  33. Fermi GBM trigger 541402602/180227234 is not a GRB
  34. GRB 180224A: Swift/UVOT Detection
  35. Konus-Wind observation of GRB 180223A
  36. GRB 180224A: OASDG optical observations
  37. IPN Triangulation of GRB 180223A (long)
  38. GRB 180210A: Insight-HXMT/HE observation
  39. Swift Trigger 811686 is probably not an astrophysical source.
  40. GRB 180224A: AbAO optical observations
  41. GRB 180224A: Swift-BAT refined analysis
  42. GRB 180224A: RATIR Optical Observations
  43. GRB 180224A: Swift-XRT refined Analysis
  44. GRB180224A: Global MASTER-Net bright OT detection
  45. GRB 180224A: Enhanced Swift-XRT position
  46. GRB 180224A: Swift detection of a burst with an optical counterpart
  47. GRB 180218A: AstroSat CZTI detection
  48. MAXI J1813-095 source: AbAO optical observations
  49. GRB 180222A: Swift/UVOT Upper Limits
  50. GRB 180221B CALET Gamma-Ray Burst Monitor detection
  51. GRB 180222A: Swift-XRT refined Analysis
  52. GRB 180222A: Swift-BAT refined analysis
  53. GRB 180222A: Enhanced Swift-XRT position
  54. GRB 180222A: A long GRB detected by INTEGRAL
  55. GRB 180222A: Swift detection of a burst
  56. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  57. Swift Trigger 811167: Detection of MAXI J1813-095
  58. GRB 180205A: Mondy optical observations
  59. GRB 180219A CALET Gamma-Ray Burst Monitor detection
  60. GRB180221A: MASTER-OAFA optical observations
  61. Swift Trigger 811074: possible GRB 180221A
  62. Konus-Wind observation of GRB 180218A
  63. GRB 180218A CALET Gamma-Ray Burst Monitor detection
  64. GRB 180218A: Fermi GBM Detection
  65. IPN Triangulation of GRB 180218A (long/bright)
  66. GRB 180204A: 15 GHz upper limits from AMI
  67. GRB 180112A: AstroSat CZTI detection
  68. Fermi GBM triggers 540405116/180215689 and 540476225/180216512 are not a GRBs
  69. Swift J1658.2-4242: Swift BAT and XRT refined analysis
  70. Swift trigger 810300: MASTER-OAFA robotic report
  71. Swift J1658.2-4242 (trigger 810300): Swift-XRT position
  72. Swift Trigger 810300 is a probable new Galactic source: Swift J1658.2-4242
  73. Konus-Wind observation of GRB 180210A
  74. GRB 180205A: SEDM Observations
  75. GRB 180210A: Swift-XRT afterglow detection
  76. GRB 180210A: Tiled Swift observations
  77. GRB 180205A: BAO optical observations
  78. Retraction of Swift trigger 809374
  79. GRB 180210A: Swift ToO observations
  80. GRB 180210A: Fermi-LAT detection
  81. GRB 180210A: Fermi GBM detection
  82. Trigger 809374: Swift detection of a possible non-burst faint source
  83. Trigger 809217: Swift trigger on RS CVn Star HD 8357
  84. GRB180205A: Optical observations with DOAO 1m telescope
  85. GRB 180205A: AbAO optical observations
  86. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  87. GRB 180205A optical observations
  88. GRB 180202A: Insight-HXMT/HE detection
  89. GRB 180204A: MITSuME Okayama optical upper limits
  90. GRB 180205A: confirmation of Swift-BAT trigger time.
  91. GRB 180205A: Optical observations
  92. GRB 180205A: Swift/UVOT Detection
  93. GRB 180205A: Nanshan-1m optical observations
  94. GRB 180205A: Swift-XRT refined Analysis
  95. GRB 180205A: Swift-BAT refined analysis
  96. GRB 180205A: Xinglong TNT optical observation
  97. GRB 180205A: Further GROND Observations reveal Afterglow is still bright
  98. GRB 180205A: Nickel telescope optical observations
  99. Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
  100. GRB 180205A: VLT polarimetry

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