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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"

20958 results found.

  1. GRB 150622A: Swift-XRT observations
  2. GRB 150622A: Tiled Swift observations
  3. V404 Cyg: Fermi GBM observations
  4. GRB 150616A: Watcher optical upper limit
  5. Swift triggers again on V404 Cyg
  6. Swift Trigger 644520 is V404 Cyg
  7. GRB 150616A: Swift/UVOT Upper Limits
  8. V404 Cyg outburst (Swift trigger 643949 ): TSHAO optical observations
  9. Konus-Wind observation of Galactic transient V404 Cyg in outburst
  10. V404 Cyg: Swift/UVOT Detection
  11. GRB 150608A: Swift-XRT follow-up observations
  12. GRB 150615A: Swift/UVOT Detection
  13. Trigger 643078: Swift detection of H1743-322
  14. GRB 150608A: Swift-XRT afterglow detection
  15. GRB150607A: AAO and CrAO optical observations
  16. GRB150607A: Discovery Channel Telescope Optical Observations
  17. GRB 150608A: Tiled Swift observations
  18. GRB 150607A: Swift/UVOT Detection
  19. GRB 150607A: NOT optical observations
  20. GRB 150518A: possible SN observations
  21. Swift Trigger 642453: a possible GRB
  22. GRB 150530B: Swift-XRT observations
  23. GRB 150527A: Continued RATIR Observations
  24. GRB 150530B: Swift ToO observations
  25. GRB 150530A: RATIR Optical Observations
  26. GRB 150530A: Swift/UVOT Upper Limits
  27. GRB 150513A: Swift-XRT observations
  28. GRB 150527A: Swift/UVOT Upper Limits
  29. GRB150527A: REM - NIR afterglow
  30. GRB 150527A: LCOGT McDonald observations
  31. GRB 150527A: RATIR Afterglow Detection
  32. GRB 150523A: Swift ToO observations
  33. GRB 150523A: Swift/UVOT Detection
  34. GRB 150523A Swift-XRT afterglow detection
  35. GRB 150523B: Swift ToO observations
  36. GRB 150518A: Continued RATIR optical observations
  37. GRB 150518A: 6.0 GHz VLA detection
  38. Disreqard the recent cluster of Swift-related GCN Circulars
  39. GRB 150518A: Mondy optical observations
  40. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  41. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  42. GRB 150518A: Swift-XRT follow-up observations
  43. GRB 150518A: SAO RAS optical observations
  44. GRB 150518A: RATIR optical observations
  45. GRB 150518A: GMG observation
  46. GRB 150518A: Xinglong2.16m optical afterglow detection
  47. Swift/UVOT observations of GRB150518A
  48. GRB 150518A: Swift-XRT afterglow detection
  49. GRB 150518A: Tiled Swift observations
  50. GRB 150514A: Further Swift observations
  51. GRB 150514A: VLT/X-shooter redshift
  52. GRB 150514A: GROND Bright Afterglow Confirmation
  53. GRB 150514A: Swift/UVOT Detection
  54. GRB 150514A: Swift-XRT afterglow detection
  55. GRB 150514A: Swift ToO observations
  56. GRB 150512A: CrAO optical observations
  57. GRB 150512A: iPTF Optical Observations
  58. GRB 150424A: 9.8 GHz VLA detection
  59. GRB 150423A: GMG observation limit
  60. GRB 150423A: JCMT SCUBA-2 sub-mm observation
  61. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  62. GRB 150430A: GROND Upper Limits
  63. GRB 150430A: Swift/UVOT Upper Limits
  64. GRB 150428B: IRSF NIR upper limits
  65. GRB 150428B: Swift/UVOT Upper Limits
  66. GRB 150428C: Swift-XRT observations
  67. GRB 150428A: Swift/UVOT Upper Limits
  68. GRB 150413A: CrAO optical observations
  69. GRB 150428B: MASTER-net prompt optical observation
  70. GRB 150428A: MASTER-net early optical observation
  71. GRB 150428C: Tiled Swift observations
  72. GRB 150428A: Danish1.56m optical observations
  73. GRB 150428A: RATIR optical observations
  74. GRB 150428A: P60 observations
  75. GRB 150428A: GROND Dark Burst Host Candidate
  76. GRB 150424A: RATIR Observations
  77. GRB 150424A: GROND detects strong fading
  78. GRB 150424A: NOT optical observations
  79. GRB 150423A: Continued RATIR optical afterglow monitoring
  80. GRB 150424A: Swift/UVOT Observations
  81. GRB 150423A: TSHAO optical observations
  82. GRB 150424B: Tiled Swift observations
  83. GRB 150423A: WHT observations
  84. GRB 150423A: Keck redshift of neighboring galaxy
  85. GRB 150423A: UKIRT NIR observations
  86. GRB 150423A: Swift/UVOT Upper Limits
  87. GRB 150423A: VLT detection
  88. GRB 150423A: RATIR optical afterglow monitoring
  89. GRB 150423A: Keck optical afterglow confirmation
  90. GRB 150423A: GROND afterglow candidate
  91. GRB 150423A: KAIT Optical Upper Limit
  92. GRB 150423A: GROND observation
  93. GRB150418A: Swift/UVOT did not detect a new source
  94. Further Swift XRT observations of GRB 150418A
  95. GRB 150413A: Swift-XRT observations
  96. GRB 150418A: Swift-XRT observations
  97. GRB 150413A: RTT150 optical observations
  98. GRB 150418A: Tiled Swift observations
  99. GRB 150413A: ISON-Ussuriysk optical observations
  100. Confirmation that Swift trigger 638217 is not an astrophysical source

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