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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 150518A: MAXI-GSC further analysis
  2. GRB 150518A: 6.0 GHz VLA detection
  3. Disreqard the recent cluster of Swift-related GCN Circulars
  4. GRB 150518A: MITSuME Akeno Optical observation
  5. GRB 150518A: Mondy optical observations
  6. GRB 150518A: AMI 15 GHz detection of possible radio counterpart
  7. GRB 150518A: MASTER-net before, early and after optical stereoscopic observations with possible MP discovery inside MAXI error box
  8. Konus-Wind observation of GRB 150518A
  9. GRB 150518A: Swift-XRT follow-up observations
  10. GRB 150518A : Xinglong TNT upper limit
  11. GRB 150518A: SAO RAS optical observations
  12. GRB 150518A: Correction
  13. GRB 150518A: VLT/X-shooter redshift of the likely host galaxy
  14. GRB 150518A: RATIR optical observations
  15. GRB 150518A: GMG observation
  16. GRB 150518A: Xinglong2.16m optical afterglow detection
  17. Swift/UVOT observations of GRB150518A
  18. GRB 150518A: Swift-XRT afterglow detection
  19. GRB 150518A: Tiled Swift observations
  20. GRB 150518A: MAXI/GSC detection
  21. GRB 150514A: Further Swift observations
  22. Konus-Wind observation of GRB 150514A
  23. GRB 150514A: VLT/X-shooter redshift
  24. GRB 150514A: GROND Bright Afterglow Confirmation
  25. GRB 150514A: Swift/UVOT Detection
  26. GRB 150514A: Fermi GBM Detection
  27. GRB 150514A: Swift-XRT afterglow detection
  28. GRB 150514A: Swift ToO observations
  29. GRB 150514A: Fermi-LAT detection
  30. GRB 150512A: CrAO optical observations
  31. GRB 150513A: Swift-BAT refined analysis
  32. GRB 150513A: Fermi GBM detection
  33. GRB 150513A: Fermi-LAT detection
  34. GRB 150512A: Fermi GBM detection
  35. GRB 150513A: Swift detection of a burst
  36. GRB 150512A: iPTF Optical Observations
  37. Konus-Wind observation of GRB 150510A
  38. GRB 150510A: Fermi GBM detection
  39. GRB 150510A: Fermi-LAT Refined Analysis
  40. GRB 150510A: Fermi-LAT detection
  41. GRB 150424A: 9.8 GHz VLA detection
  42. GRB 150423A: GMG observation limit
  43. Konus-Wind observation of GRB 150428A
  44. GRB 150423A: Chandra X-ray Observation
  45. Confirmation that Swift Trigger 639636 is not astrophysical
  46. Swift Trigger 639636: a possible GRB
  47. GRB 150423A: JCMT SCUBA-2 sub-mm observation
  48. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  49. GRB 150430A: GROND Upper Limits
  50. GRB 150430A: Swift-BAT refined analysis
  51. Konus-Wind observation of GRB 150430A
  52. GRB 150430A: Fermi GBM Detection
  53. GRB 150430A: Swift-XRT refined Analysis
  54. GRB 150430A: MAXI/GSC detection
  55. GRB 150430A: Swift/UVOT Upper Limits
  56. GRB 150430A: Swift detection of a burst
  57. GRB 150428B: IRSF NIR upper limits
  58. GRB 150428B: Swift/UVOT Upper Limits
  59. GRB 150428C: Swift-XRT observations
  60. GRB 150428A: Swift/UVOT Upper Limits
  61. GRB 150413A: CrAO optical observations
  62. GRB 150426A: Fermi GBM detection
  63. GRB 150428C: MASTER-net automatic optical inspection
  64. GRB 150428B: Swift-XRT refined Analysis
  65. GRB 150428B: MASTER-net prompt optical observation
  66. Fermi GBM trigger 150424722 is not a GRB
  67. GRB 150428A: MASTER-net early optical observation
  68. GRB 150428A: Swift-XRT refined Analysis
  69. GRB 150428B: Swift-BAT refined analysis
  70. GRB 150428C: Tiled Swift observations
  71. GRB 150428A: Swift-BAT refined analysis
  72. GRB 150428B: Enhanced Swift-XRT position
  73. GRB 150428C/MAXI J0400+678: MAXI/GSC detection
  74. GRB 150428A: Danish1.56m optical observations
  75. GRB 150428A: RATIR optical observations
  76. GRB 150428A: P60 observations
  77. GRB 150428A: Enhanced Swift-XRT position
  78. GRB 150428A: GROND Dark Burst Host Candidate
  79. GRB 150428B: Swift detection of a burst
  80. GRB 150428A: Swift detection of a burst
  81. Trigger 639199: Swift detection of IGRJ16418-4532
  82. GRB 150423A: MITSuME Akeno Optical observation
  83. GRB 150424A: RATIR Observations
  84. GRB 150424A: Swift-BAT refined analysis
  85. GRB 150424A: Swift-XRT refined Analysis
  86. GRB 150424A: spectral lag, extended-time emission
  87. GRB 150424A: 10.4m GTC spectroscopy
  88. GRB 150424A: GROND detects strong fading
  89. GRB 150424A: NOT optical observations
  90. GRB 150423A: VLT/X-shooter spectroscopy and tentative redshift
  91. GRB 150423A: Continued RATIR optical afterglow monitoring
  92. GRB 150424B: Fermi GBM detection
  93. Konus-Wind observation of GRB 150424A
  94. GRB 150424A: Swift/UVOT Observations
  95. GRB 150423A: TSHAO optical observations
  96. GRB 150424A: Enhanced Swift-XRT position
  97. GRB 150424B: Tiled Swift observations
  98. GRB 150423A: WHT observations
  99. GRB 150424B: MAXI/GSC detection
  100. GRB 150424A: Keck detection of optical afterglow

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