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

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