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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 150323C: Mondy optical observations
  2. GRB 150323B : Xinglong TNT upper limit
  3. GRB 150323C, Swift-BAT refined analysis
  4. GRB 150323C: RATIR Optical Afterglow Observations - Errata
  5. GRB 150323C: Swift/UVOT Upper Limits
  6. GRB 150323B: Swift-XRT observations
  7. GRB 150323C: Enhanced Swift-XRT position
  8. GRB 150323C: RATIR Optical Afterglow Observations
  9. GRB 150323C : Xinglong TNT optical observation
  10. GRB 150323C: Swift-XRT refined Analysis
  11. GRB 150323C: Xingming upper limit
  12. GRB 150323A, Swift-BAT refined analysis
  13. GRB150323C: Fermi GBM detection
  14. GRB 150323A: KAIT Optical Observations
  15. GRB 150323C: Nanshan optical afterglow detection
  16. GRB 150323C: Prompt enhanced Swift-XRT position
  17. GRB 150323B: Fermi GBM observation
  18. GRB 150323C: MASTER-net optical observation
  19. GRB 150323C: Swift detection of a burst
  20. GRB 150323B: Swift ToO observations
  21. GRB 150323B detected in ground analysis of Swift-BAT data
  22. GRB 150323A: Swift-XRT refined Analysis
  23. GRB150323A: Swift-UVOT detection of the afterglow
  24. GRB 150323A: Keck redshift
  25. GRB 150323A: Enhanced Swift-XRT position
  26. GRB 150314A: GMG observation limit
  27. GRB 150323A: RATIR Optical Afterglow Observations
  28. GRB 150323A: P60 Optical Afterglow Candidate
  29. GRB 150323A: Swift detection of a burst
  30. Swift Triggers 635788-635794 are probably not real.
  31. Fermi GBM trigger 150319666 is not a GRB
  32. GRB 150318A: Swift-XRT refined Analysis
  33. Confirmation that Swift trigger 635306 is not an astrophysical source
  34. GRB 150314A: Further VLA observations
  35. GRB 150318A: Skynet PROMPT-CTIO Observations
  36. GRB 150318A: Swift-BAT refined analysis
  37. GRB 150318A: Swift/UVOT Upper Limits
  38. GRB 150318A : GROND upper limits
  39. Swift Trigger 635306 is probably not an astrophysical source
  40. GRB 150318A: Enhanced Swift-XRT position
  41. GRB 150318A: Swift detection of a burst
  42. GRB 150317A: Swift/UVOT Upper Limits
  43. GRB 150317A: Swift-XRT refined Analysis
  44. GRB 150317A: Swift-BAT refined analysis
  45. GRB 150317A: RATIR Optical Afterglow Detection
  46. GRB 150317A: Enhanced Swift-XRT position
  47. GRB 150317A: NOT optical observations
  48. GRB 150317A: Swift detection of a burst
  49. GRB 150314A: VLA observations
  50. GRB 150314A: Early RAPTOR Detection
  51. GRB 150220A, the review of the sky area in plate archives
  52. GRB 150314A: NOT further optical observations
  53. Konus-Wind observation of GRB 150314A
  54. GRB 150314A: Swift-XRT refined Analysis
  55. GRB 150314A: KAIT Optical Observations
  56. GRB 150314A: P60 observations
  57. GRB 150314A: Redshift from OSIRIS/GTC
  58. GRB 150314A: NOT optical observations
  59. GRB 150314A Swift-BAT refined analysis
  60. GRB 150314A: Swift/UVOT Detection
  61. GRB 150314A: Fermi GBM observation
  62. GRB 150314A: MITSuME Akeno upper limits
  63. GRB 150314A: Skynet Yerkes-41 Observations of the Optical Afterglow
  64. GRB 150314A: Fermi-LAT detection
  65. GRB 150314A: Enhanced Swift-XRT position
  66. GRB 150314A: KAIT Optical Candidate
  67. GRB 150314A: Swift detection of a bright burst
  68. GRB 150313A: MAXI/GSC detection
  69. Fermi GBM trigger 150312827 is not a GRB
  70. GRB 150309A: AAO optic upper limit
  71. GRB 150311A: Konus-Wind trigger at 16:16:24 is not a GRB
  72. GRB 150311A: MAXI/GSC possible afterglow detection
  73. GRB 150222A: CrAO optical observation
  74. Konus-Wind observation of GRB 150309A
  75. GRB 150309A: CrAO optic upper limit
  76. GRB 150309A: ISON-Kislovodsk optic upper limit
  77. Fermi GBM trigger 150311331 is not a GRB
  78. GRB 150309A: Swift-BAT refined analysis
  79. GRB 150309A: Fermi GBM detection
  80. GRB150309A: Optical observations at Crni Vrh
  81. GRB 150309A: Swift/UVOT Upper Limits
  82. GRB 150309A: MASTER prompt optical observation
  83. GRB 150309A: Swift-XRT refined Analysis
  84. GRB 150309A : Liverpool Telescope observations
  85. GRB 150309A: Enhanced Swift-XRT position
  86. GRB 150309A: BOOTES-1 and -2 upper limit
  87. GRB 150309A: Swift detection of a burst
  88. GRB 150305A: a long GRB detected by INTEGRAL
  89. GRB 150305A: Swift XRT confirms weak INTEGRAL event as a new GRB
  90. Fermi GBM trigger 150307942 is not a GRB
  91. Chandra X-ray observations of SWIFT J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka p[PFH2005] 622)
  92. Swift J0045.2+4151: analysis of XMM-Newton archival data
  93. Further UVOT Observations of Swift J0045.2+4151
  94. Fermi GBM trigger 150305751 is not a GRB
  95. GRB 150301C: VLA Observations
  96. Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622)
  97. BAT trigger 633105 (GRB 150301C): NOT r-band upper limit
  98. GRB 150302A: BOOTES-2/TELMA upper limit
  99. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  100. GRB 150302A: Mondy optical upper limit

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