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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 150430A: Swift-BAT refined analysis
  2. Konus-Wind observation of GRB 150430A
  3. GRB 150430A: Fermi GBM Detection
  4. GRB 150430A: Swift-XRT refined Analysis
  5. GRB 150430A: MAXI/GSC detection
  6. GRB 150430A: Swift/UVOT Upper Limits
  7. GRB 150430A: Swift detection of a burst
  8. GRB 150428B: IRSF NIR upper limits
  9. GRB 150428B: Swift/UVOT Upper Limits
  10. GRB 150428C: Swift-XRT observations
  11. GRB 150428A: Swift/UVOT Upper Limits
  12. GRB 150413A: CrAO optical observations
  13. GRB 150426A: Fermi GBM detection
  14. GRB 150428C: MASTER-net automatic optical inspection
  15. GRB 150428B: Swift-XRT refined Analysis
  16. GRB 150428B: MASTER-net prompt optical observation
  17. Fermi GBM trigger 150424722 is not a GRB
  18. GRB 150428A: MASTER-net early optical observation
  19. GRB 150428A: Swift-XRT refined Analysis
  20. GRB 150428B: Swift-BAT refined analysis
  21. GRB 150428C: Tiled Swift observations
  22. GRB 150428A: Swift-BAT refined analysis
  23. GRB 150428B: Enhanced Swift-XRT position
  24. GRB 150428C/MAXI J0400+678: MAXI/GSC detection
  25. GRB 150428A: Danish1.56m optical observations
  26. GRB 150428A: RATIR optical observations
  27. GRB 150428A: P60 observations
  28. GRB 150428A: Enhanced Swift-XRT position
  29. GRB 150428A: GROND Dark Burst Host Candidate
  30. GRB 150428B: Swift detection of a burst
  31. GRB 150428A: Swift detection of a burst
  32. Trigger 639199: Swift detection of IGRJ16418-4532
  33. GRB 150423A: MITSuME Akeno Optical observation
  34. GRB 150424A: RATIR Observations
  35. GRB 150424A: Swift-BAT refined analysis
  36. GRB 150424A: Swift-XRT refined Analysis
  37. GRB 150424A: spectral lag, extended-time emission
  38. GRB 150424A: 10.4m GTC spectroscopy
  39. GRB 150424A: GROND detects strong fading
  40. GRB 150424A: NOT optical observations
  41. GRB 150423A: VLT/X-shooter spectroscopy and tentative redshift
  42. GRB 150423A: Continued RATIR optical afterglow monitoring
  43. GRB 150424B: Fermi GBM detection
  44. Konus-Wind observation of GRB 150424A
  45. GRB 150424A: Swift/UVOT Observations
  46. GRB 150423A: TSHAO optical observations
  47. GRB 150424A: Enhanced Swift-XRT position
  48. GRB 150424B: Tiled Swift observations
  49. GRB 150423A: WHT observations
  50. GRB 150424B: MAXI/GSC detection
  51. GRB 150424A: Keck detection of optical afterglow
  52. GRB 150423A: Keck redshift of neighboring galaxy
  53. GRB 150424A: Swift detection of a short burst
  54. GRB 150423A: MITSuME Okayama upper limits
  55. GRB 150423A: UKIRT NIR observations
  56. GRB 150423A: Swift-BAT refined analysis
  57. GRB 150423A: Swift/UVOT Upper Limits
  58. GRB 150423A: VLT detection
  59. GRB 150423A: Swift-XRT refined Analysis
  60. GRB 150423A: RATIR optical afterglow monitoring
  61. GRB 150423A: Enhanced Swift-XRT position
  62. GRB 150422A: Fermi GBM detection
  63. GRB 150423A: Keck optical afterglow confirmation
  64. GRB 150423A: GROND afterglow candidate
  65. GRB 150413A: Konus-Wind and Swift/BAT joint spectral analysis
  66. GRB 150423A: KAIT Optical Upper Limit
  67. GRB 150423A: GROND observation
  68. GRB 150423A: Swift detection of a short burst
  69. Konus-Wind observation of GRB 150418A
  70. GRB150418A: Swift/UVOT did not detect a new source
  71. Further Swift XRT observations of GRB 150418A
  72. Swift trigger 638589 is probably not an astrophysical source
  73. GRB 150413A: Swift-XRT observations
  74. GRB 150418A: Swift-XRT observations
  75. GRB 150413A: RTT150 optical observations
  76. GRB 150418A: Tiled Swift observations
  77. GRB 150418A: MAXI/GSC detection
  78. GRB 150413A: ISON-Ussuriysk optical observations
  79. GRB 150416A: Fermi GBM detection
  80. Confirmation that Swift trigger 638217 is not an astrophysical source
  81. GRB 150413A: MITSuME Akeno Optical observation
  82. GRB 150413A: SAO RAS observations
  83. LOAO B, R Observations of GRB150413A
  84. Swift Trigger 638217 is probably not an astrophysical source
  85. GRB 150416A: Fermi-LAT detection
  86. GRB 150413A: Refined redshift
  87. GRB 150413A: GMG observation
  88. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  89. GRB 150413A: additional P60 observations
  90. GRB 150413A : Virtual Telescope optical observations
  91. GRB 150413A
  92. GRB 150413A: Bassano Bresciano Observatory optical observations
  93. Konus-Wind observation of a bright burst from SGR 1935+2154
  94. GRB 150413A: T7 and T18 optical observations
  95. GRB 150413A: Swift-BAT refined analysis
  96. GRB150413A, optical observations
  97. IPN Triangulation of a bright burst from SGR 1935+2154
  98. GRB 150413A: optical observations
  99. GRB 150413A: redshift determination with the 2.2m CAHA
  100. GRB 150413A: P60 photometry

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