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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 180630A: Swift detection of a burst with an optical counterpart
  2. GRB 180626C: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 551697835)
  3. GRB 180626A: TSHAO optical upper limit
  4. Konus-Wind observation of GRB 180626A
  5. Konus-Wind observation of GRB 180626C
  6. GRB 180624A: NOT optical counterpart
  7. Konus-Wind observation of GRB 180626B
  8. GRB 180626A: RATIR Optical Observations
  9. IPN Triangulation of GRB 180626C (short)
  10. IPN Triangulation of GRB 180626B (short)
  11. GRB 180626A: Swift-BAT refined analysis
  12. GRB 180626A: KAIT Optical Upper Limit
  13. GRB 180626A: Swift-XRT refined Analysis
  14. GRB 180626A: COATLI Optical Detection
  15. GRB 180624A: LCO Haleakala observations
  16. GRB 180626A: Swift/UVOT Detection
  17. Konus-Wind observation of GRB 180623A
  18. GRB 180626A: RATIR Optical Detection
  19. GRB 180626A: LCO Haleakala observations
  20. GRB 180626A: ISON-MN optical observations
  21. GRB 180626A: Enhanced Swift-XRT position
  22. GRB 180626A: A long GRB detected by INTEGRAL
  23. GRB 180626A: Swift detection of a burst with an optical counterpart
  24. GRB 180623B: CALET Gamma-Ray Burst Monitor detection
  25. GRB 180624A: Swift-BAT refined analysis
  26. AT2018cow: Swift/BAT data search
  27. GRB 180624A: RATIR Optical Observations
  28. GRB 180624A: LBT/MODS redshift measurement
  29. GRB 180620B: AstroSat CZTI detection
  30. GRB 180620A: AstroSat CZTI detection
  31. GRB 180618A: AstroSat CZTI detection
  32. GRB 180613A: LCO Afterglow detection
  33. GRB 180624A: GROND observations
  34. GRB 180624A: LCO Siding Springs afterglow candidate
  35. GRB 180624A: MITSuME Okayama optical upper limits
  36. GRB 180624A: Swift-XRT refined Analysis
  37. GRB 180624A: Swift/UVOT Upper Limits
  38. GRB 180624A: Enhanced Swift-XRT position
  39. GRB 180623A: retraction of the Swift/UVOT Detection
  40. GRB 180623A: Swift-BAT refined analysis
  41. GRB 180624A: Swift detection of a burst
  42. GRB 180623A: Swift/UVOT Detection
  43. GRB 180623A: Swift-XRT refined Analysis
  44. GRB 180623A: Enhanced Swift-XRT position
  45. GRB 180623A: Swift detection of a burst
  46. GRB 180620B: Swift/UVOT Detection
  47. GRB 180620A iTelescope observation
  48. Konus-Wind observation of GRB 180620B
  49. Konus-Wind observation of GRB 180620A
  50. GRB 180620B: VLT/X-shooter redshift
  51. Konus-Wind observation of GRB 180618A (a short GRB with extended emission)
  52. GRB 180620B: Swift-BAT refined analysis
  53. GRB 180613A: Afterglow confirmation and added photometry
  54. GROND observations of GRB 180620B
  55. GROND observations of GRB 180620A
  56. GRB 180620B: Swift-XRT refined Analysis
  57. GRB 180618B: CALET Gamma-Ray Burst Monitor detection
  58. GRB 180620A: Swift-BAT refined analysis
  59. GRB 180620B: Enhanced Swift-XRT position
  60. GRB 180620B: Fermi GBM detection
  61. GRB 180620A: KAIT Optical Observations
  62. GRB 180620A: Xinglong-2.16m optical observations
  63. GRB 180618A: Swift/UVOT Detection
  64. GRB 180618A: TSHAO optical upper limit
  65. GRB 180620A: Swift-XRT refined Analysis
  66. GRB 180620B: Swift detection of a burst with an optical counterpart
  67. GRB 180620A: COATLI Detection and Light Curve
  68. GRB 180620A: Swift/UVOT Detection
  69. GRB 180618A: Xinglong-2.16m optical upper limit
  70. GRB 180620A: LCO McDonald observations
  71. GRB 180620A: Enhanced Swift-XRT position
  72. GRB 180620A: MASTER OT observation
  73. GRB 180620A: ISON-MN afterglow confirmation
  74. GRB 180620A: RATIR Optical Afterglow Detection
  75. GRB 180620A: Swift detection of a burst with an optical counterpart
  76. GRB 180618A: MASTER OT observation (a short GRB with extended emission)
  77. GRB 180618A: Swift-BAT refined analysis (a short GRB with extended emission)
  78. GRB 180611A: AstroSat CZTI detection
  79. GRB 180618A: Fermi GBM detection
  80. GRB 180618A: Swift-XRT refined Analysis
  81. GRB 180618A: LT prompt observations
  82. GRB 180618A: Enhanced Swift-XRT position
  83. GRB 180618A: Swift detection of a burst with an optical counterpart
  84. GRB 180614A: AbAO optical observations
  85. GRB 180614A: 1.5m OSN I-band observation
  86. GRB 180614A: Swift/UVOT Upper Limits
  87. GRB 180614A: Swift-BAT refined analysis
  88. GRB 180529A: AstroSat CZTI detection
  89. GRB 180614A: NOT optical upper limits
  90. GRB 180614A: MASTER observation
  91. GRB 180614A: Swift-XRT refined Analysis
  92. GRB 180614A: Enhanced Swift-XRT position
  93. GRB 180614A: Swift detection of a burst
  94. GRB 180613A: Swift/UVOT Upper Limits
  95. GRB 180613A GROND observations: correction
  96. GRB 180613A GROND observations
  97. GRB 180613A, Swift-BAT refined analysis
  98. GRB 180613A: Possible IR afterglow
  99. GRB 180613A: Swift-XRT refined Analysis
  100. GRB 180613A: Enhanced Swift-XRT position

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