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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"

19603 results found.

  1. GRB 150626B: MASTER observations
  2. GRB 150626B: Swift detection of a burst
  3. GRB 150626A: Swift-XRT refined Analysis
  4. GRB 150626A: Swift/UVOT Upper Limits
  5. Trigger 646721: Swift detection of V 404 Cyg
  6. GRB 150626A: Enhanced Swift-XRT position
  7. GRB 150626A: Prompt enhanced Swift-XRT position
  8. GRB 150626A: Swift detection of a burst
  9. Swift Trigger 646423 is GS 1354-645
  10. Trigger 645944: Swift detection of H1745-203
  11. V404 Cyg: MASTER Swift, Integral alert observations
  12. GRB 150622A: Swift-XRT observations
  13. GRB 150622A: Tiled Swift observations
  14. Swift Trigger 645340 was Sco X-1
  15. Swift Trigger 645340: a possible GRB
  16. Trigger 645176: Swift detection of V404 Cyg
  17. Swift triggers again on V404 Cyg
  18. Swift Trigger 644596 is V404 Cyg
  19. Swift Trigger 644520 is V404 Cyg
  20. GRB 150616A: Swift/UVOT Upper Limits
  21. GRB 150616A: Swift-BAT refined analysis
  22. V404 Cyg outburst (Swift trigger 643949 ): TSHAO optical observations
  23. GRB 150616A: Swift-XRT refined Analysis
  24. Konus-Wind observation of Galactic transient V404 Cyg in outburst
  25. GRB 150616A: Enhanced Swift-XRT position
  26. GRB 150616A: Swift detection of a burst
  27. V404 Cyg: Swift/UVOT Detection
  28. Optical follow-up of Swift trigger on V404 Cyg
  29. GRB 150615A, Swift-BAT refined analysis
  30. Swift trigger 643949 is V404 Cyg
  31. GRB 150615A: Swift-XRT refined Analysis
  32. GRB 150608A: Swift-XRT follow-up observations
  33. GRB 150615A: Swift/UVOT Detection
  34. GRB 150615A: Enhanced Swift-XRT position
  35. GRB 150615A: Swift detection of a burst
  36. GRB 150608A: MITSuME Akeno optical upper limits
  37. Trigger 643078: Swift detection of H1743-322
  38. GRB 150608A: Swift-XRT afterglow detection
  39. GRB150607A: AAO and CrAO optical observations
  40. GRB150607A: Discovery Channel Telescope Optical Observations
  41. GRB 150608A: Tiled Swift observations
  42. Konus-Wind observation of GRB 150607A
  43. GRB 150607A: Swift-XRT refined Analysis
  44. GRB 150607A: Swift/UVOT Detection
  45. GRB 150607A: Swift-BAT refined analysis
  46. GRB 150607A: Fermi GBM Detection
  47. GRB 150607A: Enhanced Swift-XRT position
  48. GRB 150607A: Swift detection of a burst with an optical counterpart
  49. Swift trigger 642453 is not an astrophysical source
  50. Swift Trigger 642453: a possible GRB
  51. Konus-Wind observation of GRB 150530A
  52. GRB 150530B: Swift-XRT observations
  53. GRB 150527A: Continued RATIR Observations
  54. Swift Triggers 642296 and 642297 are not GRBs
  55. GRB 150530B: Swift ToO observations
  56. GRB 150530B detected in ground analysis of BAT data
  57. GRB 150530A: RATIR Optical Observations
  58. GRB 150530A: Swift-XRT refined Analysis
  59. GRB 150530A: Swift/UVOT Upper Limits
  60. GRB 150530A: Fermi GBM observation
  61. GRB 150530A: Swift-BAT refined analysis
  62. GRB 150530A: Enhanced Swift-XRT position
  63. GRB 150530A: Swift detection of a burst
  64. GRB 150513A: Swift-XRT observations
  65. Konus-Wind observation of GRB 150527A
  66. GRB 150527A: Swift-XRT refined Analysis
  67. GRB 150527A: Swift/UVOT Upper Limits
  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. GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
  79. Confirmation that Swift Trigger 641332 is not astrophysical
  80. GRB 150523A Swift-XRT afterglow detection
  81. GRB 150523B: Swift ToO observations
  82. GRB 150523A: Fermi-LAT detection
  83. Swift trigger 641332 is probably not an astrophysical source
  84. GRB 150518A: Continued RATIR optical observations
  85. GRB 150518A: MAXI-GSC further analysis
  86. GRB 150518A: 6.0 GHz VLA detection
  87. Disreqard the recent cluster of Swift-related GCN Circulars
  88. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  89. GRB 150518A: Swift-XRT follow-up observations
  90. GRB 150518A : Xinglong TNT upper limit
  91. GRB 150518A: RATIR optical observations
  92. GRB 150518A: GMG observation
  93. Swift/UVOT observations of GRB150518A
  94. GRB 150518A: Swift-XRT afterglow detection
  95. GRB 150518A: Tiled Swift observations
  96. GRB 150514A: Further Swift observations
  97. GRB 150514A: Swift/UVOT Detection
  98. GRB 150514A: Fermi GBM Detection
  99. GRB 150514A: Swift-XRT afterglow detection
  100. GRB 150514A: Swift ToO observations

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Download all Circulars as a .tar.gz archive (updated once a day):
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