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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"

19041 results found.

  1. GRB 150728A: AAO optical observations
  2. GRB 150728A: Swift/UVOT Upper Limits
  3. GRB 150728A: Swift-BAT refined analysis
  4. GRB 150728A: FTN observations
  5. GRB 150727A: RATIR Optical Observations
  6. GRB 150728A: Enhanced Swift-XRT position
  7. GRB 150728A: Swift detection of a GRB
  8. GRB 150727A: Swift-BAT refined analysis
  9. GRB 150727A: Watcher optical upper limit
  10. GRB 150727A: Swift/UVOT Detection
  11. GRB 150727A: Swift-XRT refined Analysis
  12. GRB 150727A: Enhanced Swift-XRT position
  13. GRB 150724B: Continued RATIR Optical Observations
  14. GRB 150727A: Swift detection of a burst with an optical counterpart
  15. GRB 150724B: Swift/UVOT Detection
  16. GRB 150724B: RATIR Optical Observations
  17. GRB 150724B: Swift ToO observations
  18. GRB 150724B: Fermi GBM detection
  19. Trigger 650221: Swift detection of a IGR J00291+5934
  20. GRB 150724A: Swift/UVOT Upper Limits
  21. GRB 150724A: Enhanced Swift-XRT position
  22. SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
  23. GRB 150724A: Swift detection of a burst
  24. GRB 150722A: Swift/UVOT Upper Limits
  25. GRB 150720A: Swift/UVOT Upper Limits
  26. GRB 150722A: Enhanced Swift-XRT position
  27. GRB 150722A: Swift-XRT observations
  28. GRB 150720A: Enhanced Swift-XRT position
  29. Swift Trigger 649706: a possible GRB or bright Galactic transient
  30. GRB 150711A: Burakan-ISON optical observations
  31. GRB 150716A: Swift/UVOT Upper Limits
  32. GRB 150716A: Continued RATIR Optical Observations
  33. GRB 150716A: P60 Candidate Optical Afterglow
  34. GRB 150716A: RATIR Optical Observations
  35. GRB 150716A: Swift detection of a burst
  36. Trigger 649113: Swift detection of SGR 1E 1841-045
  37. GRB 150710B: Swift-XRT afterglow detection
  38. GRB 150710B: Swift-XRT and Swift-UVOT observations
  39. GRB 150711A: Swift/UVOT Upper Limits
  40. GRB 150711A: Observations from the 2.5m NOT
  41. GRB 150711A: Enhanced Swift-XRT position
  42. GRB 150711A: Swift detection of a burst
  43. GRB 150710B: Swift ToO observations
  44. GRB 150710A: Swift/UVOT Upper Limits
  45. GRB 150710A: Swift-BAT refined analysis
  46. GRB 150710A: RATIR Observations
  47. Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
  48. Swift Trigger 648422: Swift-XRT observations
  49. IPN Triangulation of GRB 150702A
  50. GRB 150702A: Swift ToO observations
  51. GRB 150702A: Fermi-LAT detection
  52. GRB 150622A: Swift-XRT afterglow detection
  53. Swift Trigger 647642 is probably not an astrophysical source
  54. GRB 150627A: Swift/UVOT Detection
  55. GRB 150626B: Swift-XRT refined Analysis
  56. GRB 150627A: Swift ToO observations
  57. GRB 150626B: Swift/UVOT Upper Limits
  58. GRB 150626B: NOT optical upper limits
  59. GRB 150626B: Enhanced Swift-XRT position
  60. GRB 150626B: Swift detection of a burst
  61. GRB 150626A: Swift/UVOT Upper Limits
  62. GRB 150626A: Enhanced Swift-XRT position
  63. GRB 150626A: Swift detection of a burst
  64. V404 Cyg: MASTER Swift, Integral alert observations
  65. GRB 150622A: Tiled Swift observations
  66. GRB 150622A: MAXI/GSC detection
  67. Swift Trigger 645340: a possible GRB
  68. GRB 150616A: Watcher optical upper limit
  69. Swift triggers again on V404 Cyg
  70. Swift Trigger 644520 is V404 Cyg
  71. GRB 150616A: Swift/UVOT Upper Limits
  72. GRB 150616A: Swift-XRT refined Analysis
  73. GRB 150616A: Enhanced Swift-XRT position
  74. GRB 150616A: Swift detection of a burst
  75. V404 Cyg: Swift/UVOT Detection
  76. Optical follow-up of Swift trigger on V404 Cyg
  77. Swift trigger 643949 is V404 Cyg
  78. GRB 150615A: Swift-XRT refined Analysis
  79. GRB 150608A: Swift-XRT follow-up observations
  80. GRB 150615A: Swift/UVOT Detection
  81. GRB 150615A: Enhanced Swift-XRT position
  82. GRB 150615A: Swift detection of a burst
  83. GRB 150608A: MITSuME Akeno optical upper limits
  84. Trigger 643078: Swift detection of H1743-322
  85. Konus-Wind observation of GRB 150608A
  86. GRB150607A: AAO and CrAO optical observations
  87. GRB150607A: Discovery Channel Telescope Optical Observations
  88. GRB 150608A: Tiled Swift observations
  89. GRB 150608A: MAXI/GSC detection
  90. GRB 150607A: Swift-XRT refined Analysis
  91. GRB 150607A: Swift/UVOT Detection
  92. GRB 150607A: NOT optical observations
  93. GRB 150607A: Swift-BAT refined analysis
  94. GRB 150607A: Enhanced Swift-XRT position
  95. GRB 150607A: Swift detection of a burst with an optical counterpart
  96. GRB 150518A: possible SN observations
  97. Swift trigger 642453 is not an astrophysical source
  98. Swift Trigger 642453: a possible GRB
  99. GRB 150530B: Swift-XRT observations
  100. GRB 150527A: Continued RATIR Observations

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