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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 150527A: Continued RATIR Observations
  2. Swift Triggers 642296 and 642297 are not GRBs
  3. GRB 150530B: Swift ToO observations
  4. GRB 150530B detected in ground analysis of BAT data
  5. GRB 150530A: RATIR Optical Observations
  6. GRB 150530A: Swift-XRT refined Analysis
  7. GRB 150530A: Swift/UVOT Upper Limits
  8. GRB 150530A: Fermi GBM observation
  9. GRB 150530A: Swift-BAT refined analysis
  10. GRB 150530A: Enhanced Swift-XRT position
  11. GRB 150530A: Swift detection of a burst
  12. Fermi GBM trigger 150529948 is not a GRB
  13. GRB 150513A: Swift-XRT observations
  14. Konus-Wind observation of GRB 150527A
  15. GRB 150527A: Swift-XRT refined Analysis
  16. GRB 150527A: MITSuME Okayama upper limits
  17. GRB 150527A: Swift/UVOT Upper Limits
  18. GRB150527A: REM - NIR afterglow
  19. GRB 150527A: Swift-BAT refined analysis
  20. GRB 150527A: Enhanced Swift-XRT position
  21. GRB 150527A: Fermi GBM observation
  22. GRB 150527A: LCOGT McDonald observations
  23. GRB 150527A: RATIR Afterglow Detection
  24. GRB 150523A: Suzaku WAM observation of the prompt emission
  25. GRB 150527A: Swift detection of a burst
  26. GRB 150523A: Swift ToO observations
  27. GRB 150523A: Swift/UVOT Detection
  28. GRB 150513A: request for X-ray follow up
  29. Konus-Wind observation of GRB 150523A
  30. GRB 150523A: LCOGT FTS afterglow confirmation
  31. GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
  32. Confirmation that Swift Trigger 641332 is not astrophysical
  33. GRB 150523A Swift-XRT afterglow detection
  34. GRB 150523B: Swift ToO observations
  35. GRB 150523A: Fermi-LAT detection
  36. GRB 150523A: Fermi GBM detection
  37. Swift trigger 641332 is probably not an astrophysical source
  38. GRB 150518A: Continued RATIR optical observations
  39. GRB 150518A: MAXI-GSC further analysis
  40. GRB 150518A: 6.0 GHz VLA detection
  41. Disreqard the recent cluster of Swift-related GCN Circulars
  42. GRB 150518A: MITSuME Akeno Optical observation
  43. GRB 150518A: Mondy optical observations
  44. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  45. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  46. Konus-Wind observation of GRB 150518A
  47. GRB 150518A: Swift-XRT follow-up observations
  48. GRB 150518A : Xinglong TNT upper limit
  49. GRB 150518A: SAO RAS optical observations
  50. GRB 150518A: Correction
  51. GRB 150518A: VLT/X-shooter redshift of the likely host galaxy
  52. GRB 150518A: RATIR optical observations
  53. GRB 150518A: GMG observation
  54. GRB 150518A: Xinglong2.16m optical afterglow detection
  55. Swift/UVOT observations of GRB150518A
  56. GRB 150518A: Swift-XRT afterglow detection
  57. GRB 150518A: Tiled Swift observations
  58. GRB 150518A: MAXI/GSC detection
  59. GRB 150514A: Further Swift observations
  60. Konus-Wind observation of GRB 150514A
  61. GRB 150514A: VLT/X-shooter redshift
  62. GRB 150514A: GROND Bright Afterglow Confirmation
  63. GRB 150514A: Swift/UVOT Detection
  64. GRB 150514A: Fermi GBM Detection
  65. GRB 150514A: Swift-XRT afterglow detection
  66. GRB 150514A: Swift ToO observations
  67. GRB 150514A: Fermi-LAT detection
  68. GRB 150512A: CrAO optical observations
  69. GRB 150513A: Swift-BAT refined analysis
  70. GRB 150513A: Fermi GBM detection
  71. GRB 150513A: Fermi-LAT detection
  72. GRB 150512A: Fermi GBM detection
  73. GRB 150513A: Swift detection of a burst
  74. GRB 150512A: iPTF Optical Observations
  75. Konus-Wind observation of GRB 150510A
  76. GRB 150510A: Fermi GBM detection
  77. GRB 150510A: Fermi-LAT Refined Analysis
  78. GRB 150510A: Fermi-LAT detection
  79. GRB 150424A: 9.8 GHz VLA detection
  80. GRB 150423A: GMG observation limit
  81. Konus-Wind observation of GRB 150428A
  82. GRB 150423A: Chandra X-ray Observation
  83. Confirmation that Swift Trigger 639636 is not astrophysical
  84. Swift Trigger 639636: a possible GRB
  85. GRB 150423A: JCMT SCUBA-2 sub-mm observation
  86. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  87. GRB 150430A: GROND Upper Limits
  88. GRB 150430A: Swift-BAT refined analysis
  89. Konus-Wind observation of GRB 150430A
  90. GRB 150430A: Fermi GBM Detection
  91. GRB 150430A: Swift-XRT refined Analysis
  92. GRB 150430A: MAXI/GSC detection
  93. GRB 150430A: Swift/UVOT Upper Limits
  94. GRB 150430A: Swift detection of a burst
  95. GRB 150428B: IRSF NIR upper limits
  96. GRB 150428B: Swift/UVOT Upper Limits
  97. GRB 150428C: Swift-XRT observations
  98. GRB 150428A: Swift/UVOT Upper Limits
  99. GRB 150413A: CrAO optical observations
  100. GRB 150426A: Fermi GBM detection

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