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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 090617: Fermi GBM detection
  2. GRB 090618: LOAO R-band Observation
  3. GRB 090618: Enhanced Swift-XRT position
  4. GRB 090618 Faulkes Telescope North observations
  5. Optical observations of GRB 090618
  6. GRB 090618: Lick/KAST Spectroscopy
  7. GRB 090618: OA behavior from KAIT
  8. GRB 090618: planned XMM-Newton observation
  9. GRB 090618: ROTSE-III Detection of Optical Counterpart
  10. GRB 090618: KAIT optical afterglow
  11. GRB090618: P60 Optical Afterglow
  12. GRB 090618: Swift detection of a bright burst with optical afterglow
  13. GRB 090616: Fermi GBM detection
  14. GRB 090612: Fermi GBM detection
  15. GRB 090610C: Fermi GBM detection
  16. GRB 090610B: Fermi GBM detection
  17. GRB 090610: Fermi GBM detection
  18. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  19. GRB 090602: Suzaku WAM observation of the prompt emission
  20. GRB 090424: WSRT Radio Observations
  21. GRB 090423: WSRT Radio Observations
  22. RXTE Discovery of Pulsations from SGR 0418+5729
  23. GRB 090531B: Fermi GBM detection
  24. Konus-RF observation of SGR burst 090605A
  25. Discovery of a new soft gamma repeater source, SGR 0418+5729
  26. GRB 090608: Fermi GBM detection
  27. GRB 090606: Fermi GBM detection
  28. GRB 090607: XRT Team Refined Analysis
  29. GRB 090607: Swift/UVOT Upper Limits
  30. GRB 090607: Swift-BAT refined analysis of the SHB
  31. GRB 090607: GRAS001 optical observations
  32. GRB 090607: Faulkes Telescope North observations
  33. GRB 090607: Swift detection of a burst
  34. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  35. GRB 090530B: Suzaku WAM observation of the prompt emission
  36. GRB 090530: Further NOT optical observations
  37. GRB 090530: RTT150 Optical Observation
  38. GRB 090602: Fermi GBM detection
  39. GRB 090529A: RTT150 Optical Observations
  40. GMRT observation of GRB 090424 afterglow
  41. GRB 090528: Suzaku WAM observation of the prompt emission
  42. GRB090529: Further NOT optical observations
  43. GRB 090531b, SMARTS optical/IR observations
  44. GRB 090531B: GROND observation
  45. GRB 090528B: Suzaku WAM observation of the prompt emission
  46. GRB 090530: Early RAPTOR Optical Observations
  47. GRB090529B: ROVOR Upper Limits
  48. GRB 090531A: SARA upper limit
  49. GRB 090531B: Swift/BAT spectral lag results
  50. GRB 090529C: Fermi GBM detection
  51. GRB 090529B: Fermi GBM detection
  52. GRB 090530B: Fermi GBM detection
  53. Corrections to GRB 090531B Swift/UVOT Upper Limits
  54. GRB 090531B, RIMOTS optical upper limits
  55. GRB 090531B: Swift/UVOT Upper Limits
  56. GRB 090528B: MASTER-II Kourovka optical limit
  57. GRB 090529: MITSuME optical observation
  58. GRB 090530: GRT Optical Observation
  59. GRB 090531B: Swift-BAT refined analysis
  60. Initial Swift/UVOT observations of GRB 090531B
  61. GRB 090531B: Swift-XRT candidate afterglow position
  62. GRB 090531B: ROTSE-III Optical Limits
  63. GRB 090531B: Swift detection of a burst
  64. GRB 090531: Swift-BAT refined analysis
  65. GRB090530: R-band Observation
  66. GRB 090530: break in light curve
  67. GRB 090529: VLT spectroscopic redshift
  68. GRB 090531: GROND upper limits
  69. GRB 090531: P60 Observations
  70. GRB 090531: Swift detection of a burst
  71. GRB 090529: NOT optical observations
  72. GRB 090530: NOT optical observations
  73. GRB090530: Swift XRT refined analysis
  74. GRB090530: Swift/UVOT afterglow detection
  75. GRB 090529: Swift-XRT refined analysis
  76. GRB 090529: OSN optical observations
  77. GRB 090528B: Fermi GBM detection
  78. GRB 090528: Fermi GBM detection
  79. GRB 090530: Enhanced Swift-XRT position
  80. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  81. GRB 090530: Swift-BAT refined analysis
  82. GRB 090530: GRAS002 refined OA analysis
  83. GRB 090530: GRAS002 optical observations
  84. GRB 090530: PAIRITEL NIR Detections
  85. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  86. GRB 090530: Swift detection of a burst with an optical counterpart
  87. GRB 090529: optical observations
  88. GRB 090529: TLS Afterglow Observations
  89. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  90. GRB 090529: Swift-BAT refined analysis
  91. GRB 090529: Enhanced Swift-XRT position
  92. GRB 090529: Preliminary Swift/UVOT Upper Limit
  93. GRB 090529: Xinglong TNT optical observation
  94. GRB 090529: Swift detection of a burst
  95. GRB 090520D: Fermi GBM detection
  96. GRB 090520C: Fermi GBM detection
  97. GRB 090520B: Fermi GBM detection
  98. GRB090518B optical limit by "Pi of the Sky"
  99. GRB 090522 : Fermi GBM detection
  100. GRB 090524: Fermi GBM detection

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