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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 150616A: Watcher optical upper limit
  2. Swift triggers again on V404 Cyg
  3. Swift Trigger 644596 is V404 Cyg
  4. Swift Trigger 644520 is V404 Cyg
  5. IBAS trigger 7015 is not a GRB
  6. GRB 150616A: Swift/UVOT Upper Limits
  7. GRB 150616A: Swift-BAT refined analysis
  8. V404 Cyg outburst (Swift trigger 643949 ): TSHAO optical observations
  9. GRB 150616A: Swift-XRT refined Analysis
  10. Konus-Wind observation of Galactic transient V404 Cyg in outburst
  11. GRB 150616A: Enhanced Swift-XRT position
  12. GRB 150616A: Swift detection of a burst
  13. Fermi GBM trigger 150616734 is not a GRB
  14. Fermi GBM trigger 150616594 is not a GRB
  15. V404 Cyg: Swift/UVOT Detection
  16. Fermi Gamma-ray Burst Monitor triggers bn150615791 and bn150615798 are not GRBs
  17. Optical follow-up of Swift trigger on V404 Cyg
  18. GRB 150615A, Swift-BAT refined analysis
  19. Swift trigger 643949 is V404 Cyg
  20. GRB 150615A: Swift-XRT refined Analysis
  21. Fermi GBM trigger 150615574 is not a GRB
  22. GRB 150608A: Swift-XRT follow-up observations
  23. GRB 150615A: Swift/UVOT Detection
  24. GRB 150615A: Enhanced Swift-XRT position
  25. GRB 150615A: Swift detection of a burst
  26. Fermi GBM trigger 150613619 is not a GRB
  27. Fermi GBM trigger 150612648 is not a GRB
  28. GRB 150608A: MITSuME Akeno optical upper limits
  29. Trigger 643078: Swift detection of H1743-322
  30. Konus-Wind observation of GRB 150608A
  31. GRB 150608A: Swift-XRT afterglow detection
  32. Fermi Gamma-ray Burst Monitor trigger 455474712 / 150608698 is not a GRB
  33. GRB150607A: AAO and CrAO optical observations
  34. GRB150607A: Discovery Channel Telescope Optical Observations
  35. GRB 150608A: Tiled Swift observations
  36. GRB 150608A: MAXI/GSC detection
  37. Konus-Wind observation of GRB 150607A
  38. GRB 150607A: Swift-XRT refined Analysis
  39. GRB 150607A: Swift/UVOT Detection
  40. GRB 150607A: NOT optical observations
  41. GRB 150607A: Swift-BAT refined analysis
  42. GRB 150607A: Fermi GBM Detection
  43. GRB 150607A: Enhanced Swift-XRT position
  44. GRB 150607A: Swift detection of a burst with an optical counterpart
  45. GRB 150518A: possible SN observations
  46. Swift trigger 642453 is not an astrophysical source
  47. Swift Trigger 642453: a possible GRB
  48. Konus-Wind observation of GRB 150530A
  49. GRB 150530B: Swift-XRT observations
  50. GRB 150527A: Continued RATIR Observations
  51. Swift Triggers 642296 and 642297 are not GRBs
  52. GRB 150530B: Swift ToO observations
  53. GRB 150530B detected in ground analysis of BAT data
  54. GRB 150530A: RATIR Optical Observations
  55. GRB 150530A: Swift-XRT refined Analysis
  56. GRB 150530A: Swift/UVOT Upper Limits
  57. GRB 150530A: Fermi GBM observation
  58. GRB 150530A: Swift-BAT refined analysis
  59. GRB 150530A: Enhanced Swift-XRT position
  60. GRB 150530A: Swift detection of a burst
  61. Fermi GBM trigger 150529948 is not a GRB
  62. GRB 150513A: Swift-XRT observations
  63. Konus-Wind observation of GRB 150527A
  64. GRB 150527A: Swift-XRT refined Analysis
  65. GRB 150527A: MITSuME Okayama upper limits
  66. GRB 150527A: Swift/UVOT Upper Limits
  67. GRB150527A: REM - NIR afterglow
  68. GRB 150527A: Swift-BAT refined analysis
  69. GRB 150527A: Enhanced Swift-XRT position
  70. GRB 150527A: Fermi GBM observation
  71. GRB 150527A: LCOGT McDonald observations
  72. GRB 150527A: RATIR Afterglow Detection
  73. GRB 150523A: Suzaku WAM observation of the prompt emission
  74. GRB 150527A: Swift detection of a burst
  75. GRB 150523A: Swift ToO observations
  76. GRB 150523A: Swift/UVOT Detection
  77. GRB 150513A: request for X-ray follow up
  78. Konus-Wind observation of GRB 150523A
  79. GRB 150523A: LCOGT FTS afterglow confirmation
  80. GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
  81. Confirmation that Swift Trigger 641332 is not astrophysical
  82. GRB 150523A Swift-XRT afterglow detection
  83. GRB 150523B: Swift ToO observations
  84. GRB 150523A: Fermi-LAT detection
  85. GRB 150523A: Fermi GBM detection
  86. Swift trigger 641332 is probably not an astrophysical source
  87. GRB 150518A: Continued RATIR optical observations
  88. GRB 150518A: MAXI-GSC further analysis
  89. GRB 150518A: 6.0 GHz VLA detection
  90. Disreqard the recent cluster of Swift-related GCN Circulars
  91. GRB 150518A: MITSuME Akeno Optical observation
  92. GRB 150518A: Mondy optical observations
  93. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  94. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  95. Konus-Wind observation of GRB 150518A
  96. GRB 150518A: Swift-XRT follow-up observations
  97. GRB 150518A : Xinglong TNT upper limit
  98. GRB 150518A: SAO RAS optical observations
  99. GRB 150518A: Correction
  100. GRB 150518A: VLT/X-shooter redshift of the likely host galaxy

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