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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 150514A: GROND Bright Afterglow Confirmation
  2. GRB 150514A: Swift/UVOT Detection
  3. GRB 150514A: Fermi GBM Detection
  4. GRB 150514A: Swift-XRT afterglow detection
  5. GRB 150514A: Swift ToO observations
  6. GRB 150514A: Fermi-LAT detection
  7. GRB 150512A: CrAO optical observations
  8. GRB 150513A: Swift-BAT refined analysis
  9. GRB 150513A: Fermi GBM detection
  10. GRB 150513A: Fermi-LAT detection
  11. GRB 150512A: Fermi GBM detection
  12. GRB 150513A: Swift detection of a burst
  13. GRB 150512A: iPTF Optical Observations
  14. Konus-Wind observation of GRB 150510A
  15. GRB 150510A: Fermi GBM detection
  16. GRB 150510A: Fermi-LAT Refined Analysis
  17. GRB 150510A: Fermi-LAT detection
  18. GRB 150424A: 9.8 GHz VLA detection
  19. GRB 150423A: GMG observation limit
  20. Konus-Wind observation of GRB 150428A
  21. GRB 150423A: Chandra X-ray Observation
  22. Confirmation that Swift Trigger 639636 is not astrophysical
  23. Swift Trigger 639636: a possible GRB
  24. GRB 150423A: JCMT SCUBA-2 sub-mm observation
  25. GRB 150413A: AMI 15 GHz confirmation of radio counterpart
  26. GRB 150430A: GROND Upper Limits
  27. GRB 150430A: Swift-BAT refined analysis
  28. Konus-Wind observation of GRB 150430A
  29. GRB 150430A: Fermi GBM Detection
  30. GRB 150430A: Swift-XRT refined Analysis
  31. GRB 150430A: MAXI/GSC detection
  32. GRB 150430A: Swift/UVOT Upper Limits
  33. GRB 150430A: Swift detection of a burst
  34. GRB 150428B: IRSF NIR upper limits
  35. GRB 150428B: Swift/UVOT Upper Limits
  36. GRB 150428C: Swift-XRT observations
  37. GRB 150428A: Swift/UVOT Upper Limits
  38. GRB 150413A: CrAO optical observations
  39. GRB 150426A: Fermi GBM detection
  40. GRB 150428C: MASTER-net automatic optical inspection
  41. GRB 150428B: Swift-XRT refined Analysis
  42. GRB 150428B: MASTER-net prompt optical observation
  43. Fermi GBM trigger 150424722 is not a GRB
  44. GRB 150428A: MASTER-net early optical observation
  45. GRB 150428A: Swift-XRT refined Analysis
  46. GRB 150428B: Swift-BAT refined analysis
  47. GRB 150428C: Tiled Swift observations
  48. GRB 150428A: Swift-BAT refined analysis
  49. GRB 150428B: Enhanced Swift-XRT position
  50. GRB 150428C/MAXI J0400+678: MAXI/GSC detection
  51. GRB 150428A: Danish1.56m optical observations
  52. GRB 150428A: RATIR optical observations
  53. GRB 150428A: P60 observations
  54. GRB 150428A: Enhanced Swift-XRT position
  55. GRB 150428A: GROND Dark Burst Host Candidate
  56. GRB 150428B: Swift detection of a burst
  57. GRB 150428A: Swift detection of a burst
  58. Trigger 639199: Swift detection of IGRJ16418-4532
  59. GRB 150423A: MITSuME Akeno Optical observation
  60. GRB 150424A: RATIR Observations
  61. GRB 150424A: Swift-BAT refined analysis
  62. GRB 150424A: Swift-XRT refined Analysis
  63. GRB 150424A: spectral lag, extended-time emission
  64. GRB 150424A: 10.4m GTC spectroscopy
  65. GRB 150424A: GROND detects strong fading
  66. GRB 150424A: NOT optical observations
  67. GRB 150423A: VLT/X-shooter spectroscopy and tentative redshift
  68. GRB 150423A: Continued RATIR optical afterglow monitoring
  69. GRB 150424B: Fermi GBM detection
  70. Konus-Wind observation of GRB 150424A
  71. GRB 150424A: Swift/UVOT Observations
  72. GRB 150423A: TSHAO optical observations
  73. GRB 150424A: Enhanced Swift-XRT position
  74. GRB 150424B: Tiled Swift observations
  75. GRB 150423A: WHT observations
  76. GRB 150424B: MAXI/GSC detection
  77. GRB 150424A: Keck detection of optical afterglow
  78. GRB 150423A: Keck redshift of neighboring galaxy
  79. GRB 150424A: Swift detection of a short burst
  80. GRB 150423A: MITSuME Okayama upper limits
  81. GRB 150423A: UKIRT NIR observations
  82. GRB 150423A: Swift-BAT refined analysis
  83. GRB 150423A: Swift/UVOT Upper Limits
  84. GRB 150423A: VLT detection
  85. GRB 150423A: Swift-XRT refined Analysis
  86. GRB 150423A: RATIR optical afterglow monitoring
  87. GRB 150423A: Enhanced Swift-XRT position
  88. GRB 150422A: Fermi GBM detection
  89. GRB 150423A: Keck optical afterglow confirmation
  90. GRB 150423A: GROND afterglow candidate
  91. GRB 150413A: Konus-Wind and Swift/BAT joint spectral analysis
  92. GRB 150423A: KAIT Optical Upper Limit
  93. GRB 150423A: GROND observation
  94. GRB 150423A: Swift detection of a short burst
  95. Konus-Wind observation of GRB 150418A
  96. GRB150418A: Swift/UVOT did not detect a new source
  97. Further Swift XRT observations of GRB 150418A
  98. Swift trigger 638589 is probably not an astrophysical source
  99. GRB 150413A: Swift-XRT observations
  100. GRB 150418A: Swift-XRT observations

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