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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: Suzaku WAM observation of the prompt emission
  2. GRB 090621A: Enhanced Swift-XRT position
  3. GRB 090623: Fermi GBM detection
  4. GRB 090621B: GRT Optical Observation
  5. GRB 090621A: GRT Optical Observation
  6. PAIRITEL observations of GRB 090618
  7. GRB 090621B: Fermi GBM detection
  8. GRB 090621B: I-band observations from 1.23m CAHA
  9. GRB 090621D: Fermi GBM detection
  10. GRB 090621B: Gemini spectrum of afterglow candidate
  11. GRB 090621C: Fermi GBM detection
  12. GRB 090621B: P60 Observations
  13. GRB 090621: Fermi GBM observation
  14. GRB 090621B: VLA observations
  15. GRB 090620: Fermi GBM detecion
  16. Konus-Wind and Konus-RF observations of GRB 090618
  17. GRB 090621B: Swift/UVOT Upper Limits
  18. GRB 090621B: Swift-BAT refined analysis
  19. GRB 090621B: Swift-XRT refined analysis
  20. GRB 090621B: RTT150 optical observations
  21. GRB 090618: RTT150 optical observations
  22. GRB 090621B: Optical Observations
  23. GRB 090621A: Swift-BAT refined analysis
  24. GRB 090621B: Swift detection of a short hard burst
  25. GRB 090621: Swift/UVOT Upper Limits
  26. GRB 090621: Swift-XRT Team refined analysis
  27. GRB090618: Spectrum and photometry from 6.0m BTA
  28. GRB 090618: BOAO V-band Observation
  29. GRB 090621: Swift detection of a burst
  30. GRB 090618: ZTSh optical observations
  31. GRB 090618 : WSRT radio detection
  32. GRB090618, underlying supernova search
  33. GRB090618: OAA-OAUV Optical observations
  34. GRB 090618: Fermi GBM observation
  35. GRB 090618, Swift-BAT refined spectral analysis
  36. VLA radio detection of GRB 090618
  37. GRB 090618 15GHz radio detection
  38. GRB090618 - Continued optical monitoring and light curve break
  39. GRB 090618: Swift-BAT refined analysis
  40. GRB 090618: SARA observations
  41. GRB090618: Swift-XRT team refined analysis
  42. GRB090618: Swift/UVOT bright afterglow detection
  43. GRB 090618: SDSS host detection
  44. Swift XRT observations of GRB 090531A
  45. GRB 090618: AGILE observations
  46. GRB 090617: Fermi GBM detection
  47. GRB 090618: LOAO R-band Observation
  48. GRB 090618: Enhanced Swift-XRT position
  49. GRB 090618 Faulkes Telescope North observations
  50. Optical observations of GRB 090618
  51. GRB 090618: Lick/KAST Spectroscopy
  52. GRB 090618: OA behavior from KAIT
  53. GRB 090618: planned XMM-Newton observation
  54. GRB 090618: ROTSE-III Detection of Optical Counterpart
  55. GRB 090618: KAIT optical afterglow
  56. GRB090618: P60 Optical Afterglow
  57. GRB 090618: Swift detection of a bright burst with optical afterglow
  58. GRB 090616: Fermi GBM detection
  59. GRB 090612: Fermi GBM detection
  60. GRB 090610C: Fermi GBM detection
  61. GRB 090610B: Fermi GBM detection
  62. GRB 090610: Fermi GBM detection
  63. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  64. GRB 090602: Suzaku WAM observation of the prompt emission
  65. GRB 090424: WSRT Radio Observations
  66. GRB 090423: WSRT Radio Observations
  67. RXTE Discovery of Pulsations from SGR 0418+5729
  68. GRB 090531B: Fermi GBM detection
  69. Konus-RF observation of SGR burst 090605A
  70. Discovery of a new soft gamma repeater source, SGR 0418+5729
  71. GRB 090608: Fermi GBM detection
  72. GRB 090606: Fermi GBM detection
  73. GRB 090607: XRT Team Refined Analysis
  74. GRB 090607: Swift/UVOT Upper Limits
  75. GRB 090607: Swift-BAT refined analysis of the SHB
  76. GRB 090607: GRAS001 optical observations
  77. GRB 090607: Faulkes Telescope North observations
  78. GRB 090607: Swift detection of a burst
  79. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  80. GRB 090530B: Suzaku WAM observation of the prompt emission
  81. GRB 090530: Further NOT optical observations
  82. GRB 090530: RTT150 Optical Observation
  83. GRB 090602: Fermi GBM detection
  84. GRB 090529A: RTT150 Optical Observations
  85. GMRT observation of GRB 090424 afterglow
  86. GRB 090528: Suzaku WAM observation of the prompt emission
  87. GRB090529: Further NOT optical observations
  88. GRB 090531b, SMARTS optical/IR observations
  89. GRB 090531B: GROND observation
  90. GRB 090528B: Suzaku WAM observation of the prompt emission
  91. GRB 090530: Early RAPTOR Optical Observations
  92. GRB090529B: ROVOR Upper Limits
  93. GRB 090531A: SARA upper limit
  94. GRB 090531B: Swift/BAT spectral lag results
  95. GRB 090529C: Fermi GBM detection
  96. GRB 090529B: Fermi GBM detection
  97. GRB 090530B: Fermi GBM detection
  98. Corrections to GRB 090531B Swift/UVOT Upper Limits
  99. GRB 090531B, RIMOTS optical upper limits
  100. GRB 090531B: Swift/UVOT Upper Limits

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