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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 180720B: MITSuME Ishigaki optical observations
  2. GRB 180720C: Swift-XRT refined Analysis
  3. GRB 180711A: AstroSat CZTI detection
  4. GRB 180721A: Swift-BAT refined analysis
  5. GRB 180720C: Swift-BAT refined analysis
  6. GRB 180721A: Swift-XRT refined Analysis
  7. GRB 180720B: Swift-BAT refined analysis
  8. GRB 180721A: Enhanced Swift-XRT position
  9. GRB 180720B: VLT/X-shooter redshift
  10. GRB 180721A: LCO Haleakala observations
  11. GRB 180721A: Swift detection of a burst
  12. GRB 180720B: MAXI/GSC detection
  13. GRB 180720C: Swift/UVOT Upper Limits
  14. GRB 180720C: LT observations
  15. GRB 180720C: Fermi GBM observation
  16. GRB 180706A: OSN detection
  17. GRB 180720B: LCO optical afterglow observations
  18. GRB 180720C: Enhanced Swift-XRT position
  19. GCN 22984 was for GRB 180720B
  20. GRB 180720B: OSN detection, fading slower?
  21. GRB 180720B: Swift-XRT refined Analysis
  22. GRB 180720B: MITSuME Akeno optical observations
  23. GRB 180720C: Swift detection of a burst or possible Galactic Transient
  24. GRB 180720B: Fermi GBM observation
  25. GRB 180720B : Fermi-LAT detection
  26. GRB 180720B : TSHAO optical observations
  27. GRB 180715A: MASTER optical observation
  28. GRB 180720B: Kanata 1.5m optical/NIR observation
  29. GRB 180720B: LCO Haleakala possible bright optical candidate
  30. Correction: Swift trigger #848890 is GRB 180720B (not GRB 180720A)
  31. GRB 180720A: Fermi GBM observation
  32. GRB 180720B: Swift detection of a burst
  33. GRB 180718A: MASTER optical observation
  34. GRB 180718B: MASTER optical observation
  35. AGILE/MCAL detection of GRB 180720A
  36. GRB180715B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 553369644)
  37. GRB 180715A: Gemini imaging upper limits
  38. GRB 180715A: Swift/UVOT Upper Limits
  39. Swift detects a flare from AX 1631.9-4752
  40. GRB 180718B: Fermi GBM detection
  41. GRB 180716A: CALET Gamma-Ray Burst Monitor detection
  42. GRB 180718A: Swift ToO observations
  43. GRB 180718B: Swift ToO observations
  44. GRB 180718B: Fermi-LAT detection
  45. GRB 180718A: Fermi GBM detection
  46. GRB 180718A short GRB detected by IPN and found in ground analysis of BAT data
  47. Swift Trigger 848621 is not an astrophysical event
  48. Trigger 848584: Swift detection of AX 1631.9-4752
  49. GRB 180715A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 180715A: LCO Sutherland observations
  51. GRB 180715A: COATLI Optical Observations
  52. GRB 180715A: Swift-XRT observations
  53. GRB 180715A: Fermi GBM detection
  54. GRB 180715A: Swift-BAT refined analysis
  55. GRB 180715A: GOTO optical limits
  56. GRB 180715A: LCO Sutherland possible optical candidate
  57. GRB 180715A: Swift-XRT observations
  58. GRB 180715A: Swift detection of a short hard burst
  59. GRB180714A: a long GRB detected by INTEGRAL
  60. IceCube-171106A: MASTER optical observation
  61. GRB 180703A: optical afterglow confirmation
  62. GRB 180711A: CALET Gamma-Ray Burst Monitor detection
  63. IceCube-170922A: First Optical observations of the Neutrino Trigger by MASTER Global Net and 25 IceCube alerts inspection.
  64. GRB 180705A: OSN observations
  65. Swift Trigger 847216: misidentification of IGR J16385-2057
  66. GRB 180709A: BOOTES-5/JGT optical observations
  67. GRB 180709A: Swift-BAT refined analysis
  68. GRB 180709A: Swift/UVOT Upper Limits
  69. GRB 180709A: Swift-XRT refined Analysis
  70. GRB 180709A: Optical limits
  71. GRB 180709A: COATLI Optical Observations
  72. GRB 180709A: Enhanced Swift-XRT position
  73. GRB 180703B: further analysis of CGBM data
  74. GRB 180703A: Swift-XRT afterglow detection
  75. GRB 180709A: Swift detection of a burst
  76. GRB 180705A: RTT150 optical upper limit
  77. Trigger 846740: Swift trigger near NGC5055
  78. Konus-Wind observation of GRB 180703A
  79. GRB 180703A: MASTER optical observation
  80. IPN Triangulation of GRB 180703A
  81. GRB 180706A: GOTO optical limits
  82. GRB 180706A: TSHAO optical observations
  83. GRB 180706A: Swift/UVOT Detection
  84. GRB 180706A: Swift-BAT refined analysis
  85. GRB 180705A: Swift-XRT refined Analysis
  86. GRB 180706A: Fermi GBM observation
  87. Konus-Wind observation of GRB 180704A
  88. GRB 180706A: Swift-XRT refined Analysis
  89. GRB 180706A: Enhanced Swift-XRT position
  90. Konus-Wind observation of GRB 180701A
  91. Konus-Wind observation of GRB 180703B
  92. GRB 180705A: TSHAO optical upper limit
  93. GRB 180705A: Swift/UVOT Upper Limits
  94. GRB 180705A: RATIR Optical Observations
  95. GRB 180706A: COATLI Optical Detection
  96. GRB 180706A: Swift detection of a burst with optical counterpart
  97. IPN Triangulation of GRB 180703B
  98. GRB 180705A: Swift-BAT refined analysis
  99. GRB 180705A: Enhanced Swift-XRT position
  100. Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs

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