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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 161017A: Enhanced Swift-XRT position
  2. GRB 161014A: Continued RATIR Optical and NIR Observations
  3. GRB 161015A: Swift/UVOT observations
  4. GRB 161017A: Swift detection of a burst with a bright optical afterglow
  5. GRB161017.74 MASTER-Net OT detection
  6. Konus-Wind observation of GRB 161015A
  7. GRB 161014A: VLT/X-shooter redshift confirmation
  8. GRB161015A: AstroSat CZTI detection
  9. Konus-Wind observation of GRB 161014A
  10. GRB 161014A: refined analysis of TSHAO optical observations
  11. GRB 161015A: Swift-XRT observations
  12. GRB 161015A: Fermi GBM detection
  13. GRB 161015A: Tiled Swift observations
  14. GRB 161015A: Fermi-LAT detection
  15. GRB161004A: Further analysis of the burst nature
  16. GRB 161014A: RATIR Optical and NIR Observations
  17. GRB 161014A: Fermi GBM observation
  18. GRB 161014A: Swift-XRT refined Analysis
  19. GRB 161014A: Swift-BAT refined analysis
  20. GRB 161014A: TNG optical observations
  21. GRB 161014A: AROMA-N Optical Observation
  22. GRB 161014A: Continued MITSuME Akeno Optical Observation
  23. GRB 161014A: Swift/UVOT Detection
  24. GRB161014A: NOT optical observations
  25. GRB 161014A: GTC spectroscopy
  26. GRB 161014A: TSHAO optical observations
  27. GRB 161011A: RATIR Optical and NIR Observations
  28. GRB 161014A: Swift-XRT and UVOT afterglow detection
  29. GRB 161014A: Kanata optical observation
  30. GRB 161014A : Xinglong TNT optical observation
  31. GRB161014A: optical afterglow candidate with the LCOGT-FTS
  32. GRB 161014A: MITSuME-Akeno optical observation
  33. GRB 161014A: Swift detection of a burst
  34. GRB 161010A: Swift/UVOT Possible Detection
  35. GRB 161010A: CALET Gamma-Ray Burst Monitor detection
  36. GRB 161011A, Swift-BAT refined analysis
  37. GRB 161011A: Swift burst of interest
  38. GRB 161011A: TSHAO afterglow candidate
  39. GRB 161011A: Swift/UVOT Upper Limits
  40. GRB 161011A: Swift-XRT refined Analysis
  41. Konus-Wind observation of GRB 161010A
  42. GRB 161011A: Enhanced Swift-XRT position
  43. GRB 161010A: Swift-XRT afterglow detection
  44. GRB 161011A: Prompt enhanced Swift-XRT position
  45. GRB 161011A: Swift detection of a burst
  46. GRB 161010A: Swift ToO observations
  47. GRB 161010A: a long GRB detected by INTEGRAL
  48. GRB 161007A: NOT optical observations
  49. GRB 161007A: AbAO optical observations
  50. GRB 161007A: Mondy optical observations
  51. GRB 161007A: Swift-BAT refined analysis
  52. GRB 161007A: Swift/UVOT Upper Limits
  53. GRB 161007A: Swift-XRT refined Analysis
  54. GRB 161007A: GTC observations
  55. GRB 161007A: Enhanced Swift-XRT position
  56. GRB 161004A: Maidanak optical observations
  57. GRB 161004A: refined analysis of TSHAO optical observations
  58. GRB 161007A: Prompt enhanced Swift-XRT position
  59. GRB 161007A: MASTER-net early optical observations
  60. GRB 161007A: Swift detection of a burst
  61. GRB 160821A: Maisoncelles observatory optical observations
  62. GRB 160925A: Kottamia R-band observation
  63. Konus-Wind observation of GRB 161004B
  64. GRB 160927A: GTC observations
  65. GRB 161004B: CALET Gamma-Ray Burst Monitor detection
  66. GRB 160927A: CALET Gamma-Ray Burst Monitor ground detection
  67. GRB 161004A: Swift-BAT refined analysis
  68. GRB 150302A: late-time imaging and optical afterglow confirmation
  69. GRB 161001A: IRSF upper limits
  70. GRB 161004B: Fermi GBM detection
  71. GRB 161004B: Swift/UVOT Upper Limits
  72. GRB161004B: AstroSat CZTI detection
  73. GRB 161004B: Swift-BAT refined analysis
  74. GRB 161004B: Swift-XRT refined Analysis
  75. GRB 161004A: RATIR Optical and NIR Observations
  76. GRB 160917B: Lomonosov BDRG gamma ray discovery
  77. GRB 161004B: Enhanced Swift-XRT position
  78. GRB 160917A: Lomonosov BDRG gamma ray detection
  79. GRB 160915A: Lomonosov BDRG gamma ray detection
  80. GRB 161004B: Prompt enhanced Swift-XRT position
  81. GRB 161004B: Swift detection of a burst
  82. GRB 161004A: SAO RAS optical upper limit
  83. GRB 161004A: Swift-XRT refined Analysis
  84. GRB 161004A: Swift/UVOT Detection
  85. GRB 161004A: Enhanced Swift-XRT position
  86. Swift Trigger 715209 is not an astrophysical event
  87. GRB 161004A: Bassano Bresciano Observatory upper limit
  88. GRB 161004A: TSHAO optical observations
  89. GRB 161004A: Swift detection of a burst with a possible optical counterpart
  90. GRB 160927A: 15 GHz upper limits from AMI
  91. Konus-Wind observation of GRB 161001A (short/hard ?)
  92. GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
  93. GRB 161001A: GROND afterglow candidate
  94. GRB 161001A, Swift-BAT refined analysis (likely a short GRB)
  95. GRB 161001A: Fermi GBM detection
  96. GRB 161001A: Swift-XRT refined Analysis
  97. GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
  98. GRB 161001A: Swift/UVOT Upper Limits
  99. GRB 161001A: Enhanced Swift-XRT position
  100. GRB 161001A: Prompt enhanced Swift-XRT position

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