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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 150323A: P60 Optical Afterglow Candidate
  2. GRB 150323A: Swift detection of a burst
  3. Swift Triggers 635788-635794 are probably not real.
  4. Fermi GBM trigger 150319666 is not a GRB
  5. GRB 150318A: Swift-XRT refined Analysis
  6. Confirmation that Swift trigger 635306 is not an astrophysical source
  7. GRB 150314A: Further VLA observations
  8. GRB 150318A: Skynet PROMPT-CTIO Observations
  9. GRB 150318A: Swift-BAT refined analysis
  10. GRB 150318A: Swift/UVOT Upper Limits
  11. GRB 150318A : GROND upper limits
  12. Swift Trigger 635306 is probably not an astrophysical source
  13. GRB 150318A: Enhanced Swift-XRT position
  14. GRB 150318A: Swift detection of a burst
  15. GRB 150317A: Swift/UVOT Upper Limits
  16. GRB 150317A: Swift-XRT refined Analysis
  17. GRB 150317A: Swift-BAT refined analysis
  18. GRB 150317A: RATIR Optical Afterglow Detection
  19. GRB 150317A: Enhanced Swift-XRT position
  20. GRB 150317A: NOT optical observations
  21. GRB 150317A: Swift detection of a burst
  22. GRB 150314A: VLA observations
  23. GRB 150314A: Early RAPTOR Detection
  24. GRB 150220A, the review of the sky area in plate archives
  25. GRB 150314A: NOT further optical observations
  26. Konus-Wind observation of GRB 150314A
  27. GRB 150314A: Swift-XRT refined Analysis
  28. GRB 150314A: KAIT Optical Observations
  29. GRB 150314A: P60 observations
  30. GRB 150314A: Redshift from OSIRIS/GTC
  31. GRB 150314A: NOT optical observations
  32. GRB 150314A Swift-BAT refined analysis
  33. GRB 150314A: Swift/UVOT Detection
  34. GRB 150314A: Fermi GBM observation
  35. GRB 150314A: MITSuME Akeno upper limits
  36. GRB 150314A: Skynet Yerkes-41 Observations of the Optical Afterglow
  37. GRB 150314A: Fermi-LAT detection
  38. GRB 150314A: Enhanced Swift-XRT position
  39. GRB 150314A: KAIT Optical Candidate
  40. GRB 150314A: Swift detection of a bright burst
  41. GRB 150313A: MAXI/GSC detection
  42. Fermi GBM trigger 150312827 is not a GRB
  43. GRB 150309A: AAO optic upper limit
  44. GRB 150311A: Konus-Wind trigger at 16:16:24 is not a GRB
  45. GRB 150311A: MAXI/GSC possible afterglow detection
  46. GRB 150222A: CrAO optical observation
  47. Konus-Wind observation of GRB 150309A
  48. GRB 150309A: CrAO optic upper limit
  49. GRB 150309A: ISON-Kislovodsk optic upper limit
  50. Fermi GBM trigger 150311331 is not a GRB
  51. GRB 150309A: Swift-BAT refined analysis
  52. GRB 150309A: Fermi GBM detection
  53. GRB150309A: Optical observations at Crni Vrh
  54. GRB 150309A: Swift/UVOT Upper Limits
  55. GRB 150309A: MASTER prompt optical observation
  56. GRB 150309A: Swift-XRT refined Analysis
  57. GRB 150309A : Liverpool Telescope observations
  58. GRB 150309A: Enhanced Swift-XRT position
  59. GRB 150309A: BOOTES-1 and -2 upper limit
  60. GRB 150309A: Swift detection of a burst
  61. GRB 150305A: a long GRB detected by INTEGRAL
  62. GRB 150305A: Swift XRT confirms weak INTEGRAL event as a new GRB
  63. Fermi GBM trigger 150307942 is not a GRB
  64. Chandra X-ray observations of SWIFT J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka p[PFH2005] 622)
  65. Swift J0045.2+4151: analysis of XMM-Newton archival data
  66. Further UVOT Observations of Swift J0045.2+4151
  67. Fermi GBM trigger 150305751 is not a GRB
  68. GRB 150301C: VLA Observations
  69. Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622)
  70. BAT trigger 633105 (GRB 150301C): NOT r-band upper limit
  71. GRB 150302A: BOOTES-2/TELMA upper limit
  72. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  73. GRB 150302A: Mondy optical upper limit
  74. GRB 150302A, Swift-BAT refined analysis
  75. GRB 150302A: Swift/UVOT Upper Limits
  76. GRB 150302A: MITSuME Okayama upper limits
  77. GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
  78. GRB 150302A: Swift-XRT refined Analysis
  79. GRB 150302A: Enhanced Swift-XRT position
  80. GRB 150301B: Swift-XRT refined Analysis
  81. GRB 150220A: further Swift-XRT observations
  82. GRB 150301B: Swift/UVOT Observations
  83. GRB 150301B: LCOGT-Sutherland observations
  84. GRB 150302A: KAIT Optical Upper Limit
  85. GRB 150302A: UVOT Observations
  86. GRB 150302A: NOT afterglow candidate
  87. GRB 150302A: Swift detection of a burst
  88. GRB 150301B: Fermi GBM detection
  89. GRB 150301B: Swift-BAT refined analysis
  90. GRB 150301B: X-shooter spectroscopy
  91. GRB 150301B: GROND afterglow observations
  92. GRB 150301A: Swift/UVOT Upper Limits
  93. GRB 150301B: Enhanced Swift-XRT position
  94. GRB 150301A: Swift-BAT refined analysis
  95. GRB 150301B: MASTER early OT detection
  96. GRB 150301A: Swift-XRT refined Analysis
  97. GRB 150301C : (Swift trigger 633105) Swift observations
  98. GRB 150301B: Swift detection of a burst with an optical afterglow
  99. Swift Trigger 633173 is probably not an astrophysical source
  100. GRB 150301A: GROND Observations

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