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

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