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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 140928A: MAXI-GSC detection
  2. GRB 140930B: MMT confirmation of the optical afterglow
  3. GRB 140930B: ISON-Kislovodsk observations
  4. GRB 140930B: WHT detection of candidate afterglow
  5. GRB 140930B: 1.23m CAHA optical observations
  6. GRB 140930B: Prompt enhanced Swift-XRT position
  7. GRB 140930B: MASTER early optical observations
  8. GRB 140930B: Swift detection of a short burst
  9. GRB140928A: Gemini-South observation
  10. GRB 140930A/MAXI J2259+524: MAXI-GSC detection
  11. Konus-Wind observation of GRB 140928A
  12. GRB 140928A: LCO-Cerro Tololo further observations
  13. IPN Triangulation of GRB 140928A
  14. GRB 140928A: LCO-Cerro Tololo observations
  15. GRB 140928A: Fermi GBM detection
  16. GRB 140928A: GROND Afterglow Candidate
  17. GRB 140928A: Swift-XRT observations
  18. GRB 140928A: Fermi-LAT detection
  19. GRB 140927A: Swift-UVOT analysis
  20. GRB 140927A: Swift-BAT refined analysis
  21. GRB 140927A: Swift-XRT refined Analysis
  22. GRB 140927A: Enhanced Swift-XRT position
  23. GRB 140927A: Swift detection of a burst
  24. Swift Trigger 613581 is not an astrophysical event
  25. Swift Trigger 613516 is not an astrophysical event
  26. GRB 140919A, Swift-BAT refined analysis
  27. GRB 140919A: Swift-XRT refined Analysis
  28. GRB 140919A: Swift/UVOT Detection
  29. GRB 140919A: GROND afterglow candidate
  30. GRB 140919A: Fermi GBM observation
  31. GRB 140919A: Enhanced Swift-XRT position
  32. GRB 140919A: Swift/UVOT observations
  33. GRB 140919A: Swift-XRT observations
  34. GRB 140919A: Swift detection of a burst
  35. GRB 140916B: LOT and iPTF follow-up of optical afterglow candidates
  36. Swift detection of outburst from 4U 1700+24
  37. GRB 140916A: Swift/UVOT Upper Limits
  38. GRB 140916A: Swift-BAT refined analysis
  39. GRB 140916A: UKIRT J-band observations
  40. GRB 140916A: Swift-XRT refined Analysis
  41. GRB 140916A: Enhanced Swift-XRT position
  42. GRB 140916A: MITSuME Okayama upper limits
  43. GRB 140916B: iPTF Optical Observations
  44. GRB 140916A: FTS observations
  45. GRB 140916A: Prompt enhanced Swift-XRT position
  46. GRB 140916A: Swift detection of a burst
  47. GRB 140907A: Continued DCT Observations
  48. Fermi GBM trigger 140913075 is not a GRB
  49. GRB 140909A: Confirmation of the Swift-XRT afterglow
  50. Possible radio detection of GRB 140903A with the GMRT
  51. GRB 140907A: Mondy optical observations
  52. GRB 140903A: Chandra detection of the afterglow
  53. GRB 140909A: Swift/UVOT Upper Limits
  54. GRB 140909A: Swift-XRT observations
  55. GRB 140907A: 1.23m CAHA optical observations
  56. GRB 140907A: TShAO observations
  57. GRB 140909A: Swift detection of a GRB
  58. Konus-Wind observation of GRB 140906C
  59. GRB 140907A: MASTER optical observations
  60. Refined IPN Triangulation of GRB 140906C
  61. GRB 140907A: Nishi-Harima NIR Observations
  62. GRB 140907A: MITSuME Akeno Optical Observation
  63. GRB 140907A: Discovery Channel Telescope observations
  64. IPN Triangulation of GRB 140906C (short/hard)
  65. GRB 140907A: T100 observations
  66. GRB 140907A: Swift-BAT refined analysis
  67. GRB 140907A: Fermi GBM Detection
  68. GRB 140907A: redshift from the 10.4m GTC telescope
  69. GRB 140907A: Swift-XRT refined Analysis
  70. GRB 140907A: Enhanced Swift-XRT position
  71. GRB 140907A: MITSuME Ishigakijima Optical Observation
  72. GRB140907A: MITSuME Okayama Optical Observation
  73. GRB 140907A : Virtual Telescope optical observations
  74. GRB140907A: Swift UVOT detection
  75. GRB 140906B: Fermi GBM Detection of a Long GRB
  76. GRB 140907A : Optical observations from Nanshan
  77. GRB 140907A: Swift detection of a burst with an optical counterpart
  78. GRB 140906A - Fermi GBM Detection
  79. GRB 140906A: iPTF optical transient candidates
  80. GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
  81. GRB 140903A: Possible optical variability
  82. GRB 140903A: NOT optical and NIR observations
  83. GRB 140901B: Swift XRT observation
  84. GRB 140903A: FTN observations
  85. GRB 140818B: TShAO optical upper limit
  86. GRB 140903A: ISON-Kislovodsk observations
  87. GRB 140903A: MAXI/GSC upper limit
  88. GRB 140903A: 6 GHz VLA detection
  89. GRB 140903A: Pan STARRS images of the field
  90. GRB 140901B: Fermi GBM detection
  91. GRB 140903A: tentative spectroscopic redshift
  92. GRB 140901B found in ground analysis of BAT data
  93. GRB 140903A: Swift/UVOT Upper Limits
  94. GRB 140903A: Swift-BAT Spectral lag analysis
  95. GRB 140903A: P60 Optical Observations
  96. GRB140903A: Discovery Channel Telescope Optical Detection
  97. GRB 140903A: Swift-BAT refined analysis
  98. GRB 140903A: Swift-XRT refined Analysis
  99. GRB 140903A: Coincident galaxy cluster in archival images
  100. GRB 140903A: Confirmed Swift detection of a short burst

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