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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 170604A: RATIR Optical and NIR Observations
  2. GRB 170604A: AbAO optical observations
  3. Swift trigger 755873: Swift BAT and XRT refined analysis
  4. GRB 170522A: confirmation of the X-ray afterglow
  5. GROND observations of GRB170604A
  6. Swift Trigger 755873: MASTER Net optical observations
  7. GRB 170604A: Swift-XRT refined Analysis
  8. GRB 170604A: GTC spectroscopic redshift
  9. GRB 170604A: Enhanced Swift-XRT position
  10. GRB 170604A: Swift-BAT refined analysis
  11. Swift Trigger 755873: D50 optical limits
  12. Swift Trigger 755873: a possible GRB
  13. GRB 170604A: optical observations
  14. GRB 170604A: Swift detection of a burst
  15. Trigger 755848: Swift spurious trigger on Cen X-3
  16. GRB 170531B: ISON/Terskol optical observations
  17. GRB 170531B: Swift/UVOT Detection
  18. GRB 170531B: SMARTS optical/IR observations
  19. GRB 170531B: Swift-BAT refined analysis
  20. GRB 170531A: Swift/UVOT Upper Limits
  21. GRB 170531B: LCO observations
  22. GRB 170531B: Swift-XRT refined Analysis
  23. GRB 170531A: MASTER Net job
  24. GRB 170531A: Swift-XRT refined Analysis
  25. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  26. GROND observations of GRB 170531B
  27. GRB 170531B: Redshift from GTC/OSIRIS
  28. GRB 170531A: ePESSTO NTT observations
  29. GRB 170531B: Enhanced Swift-XRT position
  30. GRB 170531B: CrAO confirmation of the afterglow
  31. GRB 170531B: MASTER Net OT detection
  32. GRB 170531A: Swift/UVOT Observations
  33. GRB 170531B: Swift detection of a burst
  34. GRB 170531A: Swift detection of a burst
  35. GRB 170519A: CrAO optical observations
  36. GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
  37. Konus-Wind observation of GRB 170529A
  38. Konus-Wind observation of GRB 170527A
  39. IPN Triangulation of GRB 170529A (long)
  40. IPN Triangulation of GRB 170527A
  41. GRB 170511A: AstroSat CZTI detection
  42. GRB 170519A: ISON/Multa optical observations
  43. GRB 170511A: Fermi GBM observation
  44. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  45. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  46. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  47. GRB 170527A: Fermi GBM detection
  48. GRB 170526A, Swift-BAT refined analysis
  49. GRB 170526A: Swift/UVOT Upper Limits
  50. GRB 170526A: Swift-XRT refined Analysis
  51. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  52. GRB 170524A: RATIR Optical and NIR Observations
  53. GRB 170526A: Enhanced Swift-XRT position
  54. GRB 170524B: Swift-XRT observations
  55. GRB 170526A: Swift detection of a burst
  56. Konus-Wind observation of GRB 170524B
  57. GRB 170524B: MASTER-OAFA observations
  58. GRB 170511A CALET Gamma-Ray Burst Monitor detection
  59. GRB 170524A: TSHAO and CrAO optical observations
  60. GRB 170524B: Swift ToO observations
  61. GRB 170524A: Swift-BAT refined analysis
  62. GRB 170524B: Swift detection of a burst
  63. GRB 170524A: Swift/UVOT Upper Limits
  64. GRB 170524A: D50 optical observation and limit
  65. GRB 170524A: Swift-XRT refined Analysis
  66. IPN Triangulation of GRB 170522A
  67. GRB 170511A: MAXI/GSC detection
  68. GRB 170524A: Enhanced Swift-XRT position
  69. GRB 170524A: Swift detection of a burst (or possible new SGR)
  70. GRB 170522A: LCO McDonald observations
  71. GRB 170522A: Swift-XRT observations
  72. GRB 170522A: Global MASTER-Net job
  73. Konus-Wind observation of GRB 170522B
  74. IPN Triangulation of GRB 170522B (long/intense)
  75. Konus-Wind observation of GRB 170522A
  76. GRB 170522A: Tiled Swift observations
  77. GRB 170522A: Fermi-LAT detection
  78. GRB 170522A: Fermi GBM detection
  79. GRB 170514A CALET Gamma-Ray Burst Monitor detection
  80. GRB 170519A: MITSuME Akeno Optical Observation
  81. GRB 170519A: Watcher optical observations
  82. GRB 170519A: Continued RATIR Optical and NIR Observations
  83. GRB 170519A: MITSuME Okayama Optical Observation
  84. GRB 170519A: NOT optical observations
  85. GRB 170519A: Redshift from GTC/OSIRIS
  86. GRB170519A, Swift-UVOT Detection
  87. GRB 170519A: BOOTES-5/JGT early optical detection
  88. LIGO/Virgo G284239: DLT40 follow-up observation
  89. GRB 170519A: KAIT Optical Observations
  90. GRB 170519A: Swift-XRT refined Analysis
  91. GRB 170519A: iTelescope T11 optical observations
  92. GRB 170519A: Swift-BAT refined analysis
  93. GRB 170519A: Weihai optical observations
  94. GRB 170510A: LCO Siding Springs early observations
  95. GRB 170519A: RATIR Optical and NIR Observations
  96. GRB 170519A: optical observations
  97. GRB 170519A: Enhanced Swift-XRT position
  98. GRB 170519A: Swift detection of a burst with an optical counterpart
  99. GRB 170510A CALET Gamma-Ray Burst Monitor detection
  100. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients

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