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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 180709A: Enhanced Swift-XRT position
  2. GRB 180703B: further analysis of CGBM data
  3. GRB 180703A: Swift-XRT afterglow detection
  4. GRB 180709A: Swift detection of a burst
  5. GRB 180705A: RTT150 optical upper limit
  6. Trigger 846740: Swift trigger near NGC5055
  7. Konus-Wind observation of GRB 180703A
  8. GRB 180703A: MASTER optical observation
  9. IPN Triangulation of GRB 180703A
  10. GRB 180706A: GOTO optical limits
  11. GRB 180706A: TSHAO optical observations
  12. GRB 180706A: Swift/UVOT Detection
  13. GRB 180706A: Swift-BAT refined analysis
  14. GRB 180705A: Swift-XRT refined Analysis
  15. GRB 180706A: Fermi GBM observation
  16. Konus-Wind observation of GRB 180704A
  17. GRB 180706A: Swift-XRT refined Analysis
  18. GRB 180706A: Enhanced Swift-XRT position
  19. Konus-Wind observation of GRB 180701A
  20. Konus-Wind observation of GRB 180703B
  21. GRB 180705A: TSHAO optical upper limit
  22. GRB 180705A: Swift/UVOT Upper Limits
  23. GRB 180705A: RATIR Optical Observations
  24. GRB 180706A: COATLI Optical Detection
  25. GRB 180706A: Swift detection of a burst with optical counterpart
  26. IPN Triangulation of GRB 180703B
  27. GRB 180705A: Swift-BAT refined analysis
  28. GRB 180705A: Enhanced Swift-XRT position
  29. Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
  30. GRB 180705A: MASTER optical observation
  31. GRB 180705A: Swift-XRT observations
  32. GRB 180705A: Swift detection of a burst
  33. GRB 180704A: AstroSat CZTI detection
  34. GRB 180703A: AstroSat CZTI detection
  35. GRB 180704B: CALET Gamma-Ray Burst Monitor detection
  36. GRB 180703A: Swift/UVOT Upper Limits
  37. GRB 180703B: Fermi GBM detection
  38. GRB 180703A: Fermi GBM detection
  39. GRB 180704A: Swift-XRT refined Analysis
  40. GRB 180704A: Swift-BAT refined analysis
  41. GRB 180704A: Swift/UVOT Upper Limits
  42. GRB 180703A: LCO Sutherland possible optical candidate
  43. GRB 180703A: Swift-XRT observations
  44. GRB 180704A: Enhanced Swift-XRT position
  45. GRB150101B: INTEGRAL prompt gamma-ray signal from a possible GRB170817A-analogue
  46. GRB 180703B: CALET Gamma-Ray Burst Monitor detection
  47. GRB 180704A: Swift-XRT observations
  48. GRB 180704A: MASTER optical observation
  49. GRB 180704A: Swift detection of a burst
  50. GRB 180703B: Fermi-LAT detection
  51. GRB 180703A: Fermi-LAT detection
  52. GRB 180703A: Tiled Swift observations
  53. GRB 180630A: Swift/UVOT Detection
  54. GRB 180701A: MAXI/GSC detection
  55. GRB 180626C : GOTO optical observations
  56. GRB 180626B : GOTO optical observations
  57. GRB 180630A: Swift-BAT refined analysis
  58. GRB 180630A: Swift-XRT refined Analysis
  59. GRB 180630A: Fermi GBM detection
  60. GRB 180626C / Fermi trigger 551697835: MASTER inspection
  61. GRB 180630A: Enhanced Swift-XRT position
  62. GRB 180630A: Swift detection of a burst with an optical counterpart
  63. GRB 180626C: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 551697835)
  64. GRB 180626A: TSHAO optical upper limit
  65. Konus-Wind observation of GRB 180626A
  66. Konus-Wind observation of GRB 180626C
  67. GRB 180624A: NOT optical counterpart
  68. Konus-Wind observation of GRB 180626B
  69. GRB 180626A: RATIR Optical Observations
  70. IPN Triangulation of GRB 180626C (short)
  71. IPN Triangulation of GRB 180626B (short)
  72. GRB 180626A: Swift-BAT refined analysis
  73. GRB 180626A: KAIT Optical Upper Limit
  74. GRB 180626A: Swift-XRT refined Analysis
  75. GRB 180626A: COATLI Optical Detection
  76. GRB 180624A: LCO Haleakala observations
  77. GRB 180626A: Swift/UVOT Detection
  78. Konus-Wind observation of GRB 180623A
  79. GRB 180626A: RATIR Optical Detection
  80. GRB 180626A: LCO Haleakala observations
  81. GRB 180626A: ISON-MN optical observations
  82. GRB 180626A: Enhanced Swift-XRT position
  83. GRB 180626A: A long GRB detected by INTEGRAL
  84. GRB 180626A: Swift detection of a burst with an optical counterpart
  85. GRB 180623B: CALET Gamma-Ray Burst Monitor detection
  86. GRB 180624A: Swift-BAT refined analysis
  87. AT2018cow: Swift/BAT data search
  88. GRB 180624A: RATIR Optical Observations
  89. GRB 180624A: LBT/MODS redshift measurement
  90. GRB 180620B: AstroSat CZTI detection
  91. GRB 180620A: AstroSat CZTI detection
  92. GRB 180618A: AstroSat CZTI detection
  93. GRB 180613A: LCO Afterglow detection
  94. GRB 180624A: GROND observations
  95. GRB 180624A: LCO Siding Springs afterglow candidate
  96. GRB 180624A: MITSuME Okayama optical upper limits
  97. GRB 180624A: Swift-XRT refined Analysis
  98. GRB 180624A: Swift/UVOT Upper Limits
  99. GRB 180624A: Enhanced Swift-XRT position
  100. GRB 180623A: retraction of the Swift/UVOT Detection

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