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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 090626: IPN localization
  2. GRB 090628: Swift/UVOT Finding Chart Observation
  3. GRB 090628: Swift XRT position
  4. GRB 090628: Swift detection of a burst
  5. Fermi LAT observations of GRB 090626
  6. GRB 090625B: Fermi GBM observation
  7. GRB 090423: Spitzer observations of the z~8.3 burst
  8. GRB 090625B: Swift/UVOT Upper Limits
  9. GRB 090625B: Swift-XRT refined analysis
  10. GRB 090626: Fermi GBM detection
  11. GRB 090625B: GROND upper limits
  12. GRB 090623: Suzaku WAM observation of the prompt emission
  13. GRB090618: HCT optical observations
  14. GRB 090618: SARA Second Epoch Observations
  15. GRB 090625B: Faulkes Telescope South observations
  16. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  17. GRB 090625B: a long GRB localized by INTEGRAL
  18. GRB 090625: Fermi GBM detection
  19. GRB 090618: Correction to GCN 9568
  20. GRB 090617: Suzaku WAM observation of the prompt emission
  21. GRB 090618: Suzaku WAM observation of the prompt emission
  22. GRB 090621A: Enhanced Swift-XRT position
  23. GRB 090623: Fermi GBM detection
  24. GRB 090621B: GRT Optical Observation
  25. GRB 090621A: GRT Optical Observation
  26. PAIRITEL observations of GRB 090618
  27. GRB 090621B: Fermi GBM detection
  28. GRB 090621B: I-band observations from 1.23m CAHA
  29. GRB 090621D: Fermi GBM detection
  30. GRB 090621B: Gemini spectrum of afterglow candidate
  31. GRB 090621C: Fermi GBM detection
  32. GRB 090621B: P60 Observations
  33. GRB 090621: Fermi GBM observation
  34. GRB 090621B: VLA observations
  35. GRB 090620: Fermi GBM detecion
  36. Konus-Wind and Konus-RF observations of GRB 090618
  37. GRB 090621B: Swift/UVOT Upper Limits
  38. GRB 090621B: Swift-BAT refined analysis
  39. GRB 090621B: Swift-XRT refined analysis
  40. GRB 090621B: RTT150 optical observations
  41. GRB 090618: RTT150 optical observations
  42. GRB 090621B: Optical Observations
  43. GRB 090621A: Swift-BAT refined analysis
  44. GRB 090621B: Swift detection of a short hard burst
  45. GRB 090621: Swift/UVOT Upper Limits
  46. GRB 090621: Swift-XRT Team refined analysis
  47. GRB090618: Spectrum and photometry from 6.0m BTA
  48. GRB 090618: BOAO V-band Observation
  49. GRB 090621: Swift detection of a burst
  50. GRB 090618: ZTSh optical observations
  51. GRB 090618 : WSRT radio detection
  52. GRB090618, underlying supernova search
  53. GRB090618: OAA-OAUV Optical observations
  54. GRB 090618: Fermi GBM observation
  55. GRB 090618, Swift-BAT refined spectral analysis
  56. VLA radio detection of GRB 090618
  57. GRB 090618 15GHz radio detection
  58. GRB090618 - Continued optical monitoring and light curve break
  59. GRB 090618: Swift-BAT refined analysis
  60. GRB 090618: SARA observations
  61. GRB090618: Swift-XRT team refined analysis
  62. GRB090618: Swift/UVOT bright afterglow detection
  63. GRB 090618: SDSS host detection
  64. Swift XRT observations of GRB 090531A
  65. GRB 090618: AGILE observations
  66. GRB 090617: Fermi GBM detection
  67. GRB 090618: LOAO R-band Observation
  68. GRB 090618: Enhanced Swift-XRT position
  69. GRB 090618 Faulkes Telescope North observations
  70. Optical observations of GRB 090618
  71. GRB 090618: Lick/KAST Spectroscopy
  72. GRB 090618: OA behavior from KAIT
  73. GRB 090618: planned XMM-Newton observation
  74. GRB 090618: ROTSE-III Detection of Optical Counterpart
  75. GRB 090618: KAIT optical afterglow
  76. GRB090618: P60 Optical Afterglow
  77. GRB 090618: Swift detection of a bright burst with optical afterglow
  78. GRB 090616: Fermi GBM detection
  79. GRB 090612: Fermi GBM detection
  80. GRB 090610C: Fermi GBM detection
  81. GRB 090610B: Fermi GBM detection
  82. GRB 090610: Fermi GBM detection
  83. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  84. GRB 090602: Suzaku WAM observation of the prompt emission
  85. GRB 090424: WSRT Radio Observations
  86. GRB 090423: WSRT Radio Observations
  87. RXTE Discovery of Pulsations from SGR 0418+5729
  88. GRB 090531B: Fermi GBM detection
  89. Konus-RF observation of SGR burst 090605A
  90. Discovery of a new soft gamma repeater source, SGR 0418+5729
  91. GRB 090608: Fermi GBM detection
  92. GRB 090606: Fermi GBM detection
  93. GRB 090607: XRT Team Refined Analysis
  94. GRB 090607: Swift/UVOT Upper Limits
  95. GRB 090607: Swift-BAT refined analysis of the SHB
  96. GRB 090607: GRAS001 optical observations
  97. GRB 090607: Faulkes Telescope North observations
  98. GRB 090607: Swift detection of a burst
  99. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  100. GRB 090530B: Suzaku WAM observation of the prompt emission

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