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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 170531B: CrAO confirmation of the afterglow
  2. GRB 170531B: MASTER Net OT detection
  3. GRB 170531A: Swift/UVOT Observations
  4. GRB 170531B: Swift detection of a burst
  5. GRB 170531A: Swift detection of a burst
  6. GRB 170519A: CrAO optical observations
  7. GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
  8. Konus-Wind observation of GRB 170529A
  9. Konus-Wind observation of GRB 170527A
  10. IPN Triangulation of GRB 170529A (long)
  11. IPN Triangulation of GRB 170527A
  12. GRB 170511A: AstroSat CZTI detection
  13. GRB 170519A: ISON/Multa optical observations
  14. GRB 170511A: Fermi GBM observation
  15. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  16. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  17. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  18. GRB 170527A: Fermi GBM detection
  19. GRB 170526A, Swift-BAT refined analysis
  20. GRB 170526A: Swift/UVOT Upper Limits
  21. GRB 170526A: Swift-XRT refined Analysis
  22. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  23. GRB 170524A: RATIR Optical and NIR Observations
  24. GRB 170526A: Enhanced Swift-XRT position
  25. GRB 170524B: Swift-XRT observations
  26. GRB 170526A: Swift detection of a burst
  27. Konus-Wind observation of GRB 170524B
  28. GRB 170524B: MASTER-OAFA observations
  29. GRB 170511A CALET Gamma-Ray Burst Monitor detection
  30. GRB 170524A: TSHAO and CrAO optical observations
  31. GRB 170524B: Swift ToO observations
  32. GRB 170524A: Swift-BAT refined analysis
  33. GRB 170524B: Swift detection of a burst
  34. GRB 170524A: Swift/UVOT Upper Limits
  35. GRB 170524A: D50 optical observation and limit
  36. GRB 170524A: Swift-XRT refined Analysis
  37. IPN Triangulation of GRB 170522A
  38. GRB 170511A: MAXI/GSC detection
  39. GRB 170524A: Enhanced Swift-XRT position
  40. GRB 170524A: Swift detection of a burst (or possible new SGR)
  41. GRB 170522A: LCO McDonald observations
  42. GRB 170522A: Swift-XRT observations
  43. GRB 170522A: Global MASTER-Net job
  44. Konus-Wind observation of GRB 170522B
  45. IPN Triangulation of GRB 170522B (long/intense)
  46. Konus-Wind observation of GRB 170522A
  47. GRB 170522A: Tiled Swift observations
  48. GRB 170522A: Fermi-LAT detection
  49. GRB 170522A: Fermi GBM detection
  50. GRB 170514A CALET Gamma-Ray Burst Monitor detection
  51. GRB 170519A: MITSuME Akeno Optical Observation
  52. GRB 170519A: Watcher optical observations
  53. GRB 170519A: Continued RATIR Optical and NIR Observations
  54. GRB 170519A: MITSuME Okayama Optical Observation
  55. GRB 170519A: NOT optical observations
  56. GRB 170519A: Redshift from GTC/OSIRIS
  57. GRB170519A, Swift-UVOT Detection
  58. GRB 170519A: BOOTES-5/JGT early optical detection
  59. LIGO/Virgo G284239: DLT40 follow-up observation
  60. GRB 170519A: KAIT Optical Observations
  61. GRB 170519A: Swift-XRT refined Analysis
  62. GRB 170519A: iTelescope T11 optical observations
  63. GRB 170519A: Swift-BAT refined analysis
  64. GRB 170519A: Weihai optical observations
  65. GRB 170510A: LCO Siding Springs early observations
  66. GRB 170519A: RATIR Optical and NIR Observations
  67. GRB 170519A: optical observations
  68. GRB 170519A: Enhanced Swift-XRT position
  69. GRB 170519A: Swift detection of a burst with an optical counterpart
  70. GRB 170510A CALET Gamma-Ray Burst Monitor detection
  71. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  72. GRB 170510A: Swift-XRT afterglow detection
  73. GRB 170516A: Swift-BAT refined analysis
  74. GRB 170516A: Swift-XRT refined Analysis
  75. AXP CXOU J164710.2-455216: Fermi GBM observation
  76. GRB 170516A: Swift/UVOT Upper Limits
  77. GRB 170516A: Enhanced Swift-XRT position
  78. GRB 170516A: Swift detection of a burst
  79. Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
  80. Swift Trigger on AXP CXOU J164710.2-455216
  81. GRB 170514A: Fermi GBM detection
  82. GRB 170510A: AstroSat CZTI(Veto) detection
  83. Fermi GBM trigger 516459580/170514541 is not a GRB
  84. GRB 170510A: Global MASTER Net possible OT observations
  85. Konus-Wind observation of GRB 170510A
  86. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  87. LIGO/Virgo G284239: Konus-Wind observations
  88. GRB 170510A: LCO possible counterpart
  89. GRB 170510A: Swift-XRT observations
  90. GRB 170510A: Fermi GBM observation
  91. LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
  92. LIGO/Virgo G284239: MAXI/GSC observations
  93. GRB 170510A: Tiled Swift observations
  94. GRB 170510A: Fermi-LAT detection
  95. Swift Trigger 752193 is not a GRB
  96. LIGO/Virgo G284239: AstroSat CZTI upper limits
  97. Trigger 751928: Swift misidentification of Cen X-3
  98. GRB 170423A: TAROT Reunion observatory optical observations
  99. IceCube-170506A - IceCube update on a high-energy neutrino candidate event
  100. Swift XRT observations of GRB 170424A

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