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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"

19574 results found.

  1. GRB 180404B: Enhanced Swift-XRT position
  2. GRB 180404A: Enhanced Swift-XRT position
  3. GRB 180404B: Swift detection of a burst with an optical counterpart
  4. GRB 180404A: Swift detection of a burst with an optical afterglow
  5. GRB 180402A: Swift/UVOT Upper Limits
  6. GRB 180402A: Swift-XRT refined Analysis
  7. GRB 180402A: Fermi GBM detection
  8. GRB 180402A: RATIR Upper Limits
  9. GRB 180402A: Swift detection of a possibly short burst
  10. GRB 180331B: Swift/UVOT Upper Limits
  11. GRB 180331B: AbAO optical observations
  12. GRB 180331B: Enhanced Swift-XRT position
  13. GRB 180331B: Swift detection of a burst
  14. GRB 180331A: Swift/UVOT Upper Limits
  15. GRB 180331A: Enhanced Swift-XRT position
  16. GRB 180331A: Swift detection of a burst
  17. GRB 180329B: Swift/UVOT Detection
  18. GRB 180329B: RATIR Optical Observations
  19. Swift Trigger 819863 is not a GRB
  20. GRB 180329B: NOT optical afterglow detection
  21. GRB 180329B: Enhanced Swift-XRT position
  22. GRB 180329B: Swift detection of a burst with an optical afterglow
  23. Swift Trigger 819301: possible GRB 180329A
  24. GRB 180325A: VLT/X-shooter spectroscopic observations
  25. GRB 180325A: Swift/UVOT Detection
  26. GRB 180325A: GROND observations
  27. GRB 180325A: TAROT Calern observatory optical observations
  28. GRB 180325A: D50 early optical follow-up
  29. GRB 180325A: Enhanced Swift-XRT position
  30. GRB 180325A: Optical Photometry with SLKT
  31. GRB 180325A: RATIR Optical Observations
  32. GRB 180325A: prompt REM optical/NIR detection
  33. GRB 180325A: NOT redshift
  34. GRB 180325A: Swift detection of a burst with an optical counterpart
  35. GRB 180324A: Swift/UVOT Upper Limits
  36. GRB 180324A: Enhanced Swift-XRT position
  37. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  38. GRB 180324A: Swift detection of a burst
  39. IPN Triangulation of GRB 180317A (short/hard)
  40. GRB 180316A: RATIR Optical Observations
  41. GRB 180316A: TSHAO optical observations
  42. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  43. GRB 180316A: Swift/UVOT Detection
  44. GRB 180316A: RATIR Optical Observations
  45. GRB 180316A: Enhanced Swift-XRT position
  46. GRB 180316A: LCO Cerro Tololo observations
  47. GROND observations of GRB 180316A
  48. GRB 180316A: Swift detection of a burst
  49. GRB 180314B: RATIR Optical Observations
  50. GRB 180314B: Zeiss-1000/CrAO optical upper limit
  51. GRB 180314B: Swift/UVOT Upper Limits
  52. GRB 180314B: Enhanced Swift-XRT position
  53. GRB 180314B: Swift detection of a burst
  54. Swift Trigger on MAXI J1820+070
  55. GRB 180314A: TAROT La Silla observatory optical observations
  56. GRB 180314A: LCO Siding Springs observations
  57. GRB 180314A: Swift/UVOT Detection
  58. GRB 180314A: REM optical/NIR observations
  59. GRB 180314A: MASTER-Net OT dtetction
  60. GRB 180314A: Enhanced Swift-XRT position
  61. GRB180314A: GROND detection of the afterglow
  62. GRB 180314A: Swift detection of a burst with an optical counterpart
  63. GRB 180311A: Swift/UVOT Upper Limits
  64. MAXI J1820+070: Swift/UVOT counterpart correction
  65. Swift detection of MAXI J1820+070
  66. GRB 180311A: Enhanced Swift-XRT position
  67. GRB 180311A: Swift detection of a burst
  68. GRB 180305A CALET Gamma-Ray Burst Monitor detection
  69. GRB 180305A: RATIR Optical Observations
  70. GRB 180305A: Swift/UVOT Upper Limits
  71. GRB 180305A: Mondy optical observations
  72. GRB 180305A: Swift-XRT afterglow detection
  73. GRB 180305A: RATIR Optical Afterglow Candidate
  74. GRB 180305A: Swift ToO observations
  75. GRB 180305A: Fermi-LAT detection
  76. GRB 180224A: Swift/UVOT Detection
  77. GRB 180224A: OASDG optical observations
  78. IPN Triangulation of GRB 180223A (long)
  79. GRB 180210A: Insight-HXMT/HE observation
  80. Swift Trigger 811686 is probably not an astrophysical source.
  81. GRB 180224A: AbAO optical observations
  82. GRB 180224A: RATIR Optical Observations
  83. GRB 180224A: Enhanced Swift-XRT position
  84. GRB 180224A: Swift detection of a burst with an optical counterpart
  85. MAXI J1813-095 source: AbAO optical observations
  86. GRB 180222A: Swift/UVOT Upper Limits
  87. GRB 180222A: Swift-BAT refined analysis
  88. GRB 180222A: Enhanced Swift-XRT position
  89. GRB 180222A: Swift detection of a burst
  90. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  91. Swift Trigger 811167: Detection of MAXI J1813-095
  92. GRB 180205A: Mondy optical observations
  93. IPN Triangulation of GRB 180218A (long/bright)
  94. GRB 180204A: 15 GHz upper limits from AMI
  95. Konus-Wind observation of GRB 180210A
  96. GRB 180205A: SEDM Observations
  97. GRB 180210A: Swift-XRT afterglow detection
  98. GRB 180210A: Tiled Swift observations
  99. GRB 180205A: BAO optical observations
  100. GRB 180210A: Swift ToO observations

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