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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 090621: Swift/UVOT Upper Limits
  2. GRB 090621: Swift-XRT Team refined analysis
  3. GRB090618: Spectrum and photometry from 6.0m BTA
  4. GRB 090618: BOAO V-band Observation
  5. GRB 090621: Swift detection of a burst
  6. GRB 090618: ZTSh optical observations
  7. GRB 090618 : WSRT radio detection
  8. GRB090618, underlying supernova search
  9. GRB090618: OAA-OAUV Optical observations
  10. GRB 090618: Fermi GBM observation
  11. GRB 090618, Swift-BAT refined spectral analysis
  12. VLA radio detection of GRB 090618
  13. GRB 090618 15GHz radio detection
  14. GRB090618 - Continued optical monitoring and light curve break
  15. GRB 090618: Swift-BAT refined analysis
  16. GRB 090618: SARA observations
  17. GRB090618: Swift-XRT team refined analysis
  18. GRB090618: Swift/UVOT bright afterglow detection
  19. GRB 090618: SDSS host detection
  20. Swift XRT observations of GRB 090531A
  21. GRB 090618: AGILE observations
  22. GRB 090617: Fermi GBM detection
  23. GRB 090618: LOAO R-band Observation
  24. GRB 090618: Enhanced Swift-XRT position
  25. GRB 090618 Faulkes Telescope North observations
  26. Optical observations of GRB 090618
  27. GRB 090618: Lick/KAST Spectroscopy
  28. GRB 090618: OA behavior from KAIT
  29. GRB 090618: planned XMM-Newton observation
  30. GRB 090618: ROTSE-III Detection of Optical Counterpart
  31. GRB 090618: KAIT optical afterglow
  32. GRB090618: P60 Optical Afterglow
  33. GRB 090618: Swift detection of a bright burst with optical afterglow
  34. GRB 090616: Fermi GBM detection
  35. GRB 090612: Fermi GBM detection
  36. GRB 090610C: Fermi GBM detection
  37. GRB 090610B: Fermi GBM detection
  38. GRB 090610: Fermi GBM detection
  39. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  40. GRB 090602: Suzaku WAM observation of the prompt emission
  41. GRB 090424: WSRT Radio Observations
  42. GRB 090423: WSRT Radio Observations
  43. RXTE Discovery of Pulsations from SGR 0418+5729
  44. GRB 090531B: Fermi GBM detection
  45. Konus-RF observation of SGR burst 090605A
  46. Discovery of a new soft gamma repeater source, SGR 0418+5729
  47. GRB 090608: Fermi GBM detection
  48. GRB 090606: Fermi GBM detection
  49. GRB 090607: XRT Team Refined Analysis
  50. GRB 090607: Swift/UVOT Upper Limits
  51. GRB 090607: Swift-BAT refined analysis of the SHB
  52. GRB 090607: GRAS001 optical observations
  53. GRB 090607: Faulkes Telescope North observations
  54. GRB 090607: Swift detection of a burst
  55. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  56. GRB 090530B: Suzaku WAM observation of the prompt emission
  57. GRB 090530: Further NOT optical observations
  58. GRB 090530: RTT150 Optical Observation
  59. GRB 090602: Fermi GBM detection
  60. GRB 090529A: RTT150 Optical Observations
  61. GMRT observation of GRB 090424 afterglow
  62. GRB 090528: Suzaku WAM observation of the prompt emission
  63. GRB090529: Further NOT optical observations
  64. GRB 090531b, SMARTS optical/IR observations
  65. GRB 090531B: GROND observation
  66. GRB 090528B: Suzaku WAM observation of the prompt emission
  67. GRB 090530: Early RAPTOR Optical Observations
  68. GRB090529B: ROVOR Upper Limits
  69. GRB 090531A: SARA upper limit
  70. GRB 090531B: Swift/BAT spectral lag results
  71. GRB 090529C: Fermi GBM detection
  72. GRB 090529B: Fermi GBM detection
  73. GRB 090530B: Fermi GBM detection
  74. Corrections to GRB 090531B Swift/UVOT Upper Limits
  75. GRB 090531B, RIMOTS optical upper limits
  76. GRB 090531B: Swift/UVOT Upper Limits
  77. GRB 090528B: MASTER-II Kourovka optical limit
  78. GRB 090529: MITSuME optical observation
  79. GRB 090530: GRT Optical Observation
  80. GRB 090531B: Swift-BAT refined analysis
  81. Initial Swift/UVOT observations of GRB 090531B
  82. GRB 090531B: Swift-XRT candidate afterglow position
  83. GRB 090531B: ROTSE-III Optical Limits
  84. GRB 090531B: Swift detection of a burst
  85. GRB 090531: Swift-BAT refined analysis
  86. GRB090530: R-band Observation
  87. GRB 090530: break in light curve
  88. GRB 090529: VLT spectroscopic redshift
  89. GRB 090531: GROND upper limits
  90. GRB 090531: P60 Observations
  91. GRB 090531: Swift detection of a burst
  92. GRB 090529: NOT optical observations
  93. GRB 090530: NOT optical observations
  94. GRB090530: Swift XRT refined analysis
  95. GRB090530: Swift/UVOT afterglow detection
  96. GRB 090529: Swift-XRT refined analysis
  97. GRB 090529: OSN optical observations
  98. GRB 090528B: Fermi GBM detection
  99. GRB 090528: Fermi GBM detection
  100. GRB 090530: Enhanced Swift-XRT position

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