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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 190114B: BOOTES-4/MET optical afterglow detection
  2. GRB 190114C: MASTER 4-polarizations filters OT detection
  3. GRB 190114C: Possible host galaxy in Pan-STARRS
  4. GRB 190114B: Enhanced Swift-XRT position
  5. GRB 190114C: MASTER afterglow Detection
  6. INTEGRAL observation of IceCube-190104A
  7. GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart
  8. GRB 190114A: OSN Detection
  9. GRB 190114B: Swift detection of a burst
  10. GRB 190114A: Swift-BAT refined analysis
  11. GRB 190103B: Swift/UVOT Upper Limits
  12. GRB 190114A: Swift-XRT refined Analysis
  13. GRB 190114A: GROND detection of the afterglow
  14. GRB 190114A: Enhanced Swift-XRT position
  15. GRB 190114A: VLT/X-shooter redshift
  16. GRB 190114A: Prompt enhanced Swift-XRT position
  17. GRB 190114A: Possible UVOT Detection
  18. GRB 190114A: Swift detection of a burst
  19. GRB 190110A：Insight-HXMT/HE detection
  20. Konus-Wind observation of GRB 190110A
  21. GRB 190110A, Swift-BAT refined analysis
  22. Correction to GCN Circular 23663: GRB 190109A: Swift UVOT Upper Limits
  23. Konus-Wind observation of GRB 190103A
  24. GRB 190110A: Fermi GBM detection
  25. GRB 190110A: Swift detection of a burst
  26. GRB 181228A: FRAM-ORM optical limit
  27. GRB 190106A: GMG continued observation
  28. IceCube-190104A: AstroSat CZTI counterpart search
  29. GRB 190109B: Fermi GBM observation
  30. GRB 190106A: OSN Afterglow Observations
  31. GRB 190109B: Swift/UVOT Upper Limits
  32. GRB 190109A: Swift/UVOT Upper Limits
  33. GRB 190109B: Swift-XRT refined Analysis
  34. GRB 190106A: optical observations, possible jet break detection
  35. GRB 190106A: Liverpool Telescope observations
  36. GRB 190109B: Swift-BAT refined analysis
  37. GRB 190109A: Fermi GBM observation
  38. Correction to the GCN circ. 23654 / GRB 190109B: Mondy optical upper limit
  39. GRB 190109B: COATLI Optical Observations
  40. GRB 190109B: BOOTES-5/JGT optical observations
  41. GRB 190109B: Mondy optical upper limit
  42. GRB 190109A: Swift-BAT refined analysis
  43. GRB 190109B: Enhanced Swift-XRT position
  44. GRB 190109B: Swift-XRT observations
  45. INTEGRAL Weak#8189: AROMA-N Optical Observation
  46. GRB190109A: MITSuME Akeno optical upper limits
  47. GRB 190109B: Swift detection of a burst
  48. CALET Gamma-Ray Burst Monitor: Policy change in the GCN circulars
  49. IPN triangulation of GRB 190103A (long)
  50. GRB 190109A: Swift-XRT refined Analysis
  51. GRB 190109A: Enhanced Swift-XRT position
  52. GRB 190109A: Prompt enhanced Swift-XRT position
  53. GRB 190109A: Swift detection of a burst
  54. IceCube-190104A: Swift-XRT observations
  55. GRB 190106A: Mondy optical observations
  56. Trigger 882561: Swift detection of MAXI J1631-479
  57. GRB 190106A : continued TSHAO optical observations
  58. Konus-Wind observation of GRB 190106A
  59. GRB 190106A: NEXT-0.6m and Xinglong-2.16m photometric single powerlaw decay
  60. IERCOO/ICSP optical observation of GRB 190106A
  61. GRB 190106A: GMG photometry in the 2nd night
  62. GRB 190106A: Swift-XRT refined Analysis
  63. GRB 190106A: VLT/X-shooter redshift confirmation
  64. GRB 190103B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 190106A: GMG spectral results
  66. GRB 190106A: update of the Xinglong-2.16m spectroscopy
  67. GRB 190106A: OASDG optical observations
  68. GRB 190106A: BOOTES-4/MET optical observations
  69. GRB 190106A: Swift/UVOT Detection
  70. GRB 190106A: Swift-BAT refined analysis
  71. GRB 190106A: Bassano Bresciano Observatory optical detection
  72. GRB 190106A: Xinglong-2.16m spectroscopy
  73. GRB 190106A: GWAC-F60B optical detection
  74. Fermi GBM Observations of IceCube-190104A
  75. GRB 190106A : TSHAO optical observations
  76. GRB 190106A: Enhanced Swift-XRT position
  77. GRB 190106A: GMG detection
  78. GRB 190106A: MITSuME Akeno optical observation
  79. GRB 190106A: MASTER Amur OT detection
  80. GRB 190106A: Swift detection of a burst with an optical counterpart
  81. SWIFT GRB190106.57 Global MASTER-Net OT detection
  82. Search for Counterparts to IceCube-190104A with IceCube
  83. Konus-Wind observation of GRB 190103B
  84. Search for counterpart to IceCube-190104A with ANTARES
  85. IceCube-190104A: MASTER optical observation
  86. GRB 190103A: AstroSat CZTI detection
  87. Fermi LAT Gamma-ray Observations of IceCube-190104A
  88. GRB 190103B: Bassano Bresciano observatory upper limit
  89. GRB 190103B: Swift-BAT refined analysis
  90. IceCube-190104A - IceCube observation of a high-energy neutrino candidate event
  91. GRB 190103B: Swift-XRT refined Analysis
  92. GRB 190103B: Enhanced Swift-XRT position
  93. GRB 190103B: Swift detection of a burst
  94. GRB 181201A: photometric signature of the SN
  95. GRB 190103A: AGILE/MCAL detection of a burst
  96. GRB 181231A: BOOTES-2/TELMA optical observations
  97. GRB 181231A: Fermi GBM detection
  98. GRB 181231A: Fermi-LAT detection
  99. GRB 181228A: Mondy and AbAO optical upper limits
  100. GRB 181225A: further Swift-XRT observations

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