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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"

23584 results found.

  1. XRF 090702: a long soft GRB localized with INTEGRAL
  2. GRB 090701: Fermi GBM detection
  3. GRB 090630: Fermi GBM detection
  4. GRB 090618: RTT150 optical observations
  5. GRB 090628: Swift/UVOT Upper Limits
  6. Konus-Wind observation of GRB 090626
  7. GRB 090628: Swift-BAT refined analysis
  8. GRB 090628: GROND upper limits
  9. GRB 090628: 1.23m CAHA optical observations
  10. GRB 090626: IPN localization
  11. GRB 090628: Swift detection of a burst
  12. GRB 090623: Suzaku WAM observation of the prompt emission
  13. GRB 090625B: Faulkes Telescope South observations
  14. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  15. GRB 090625B: a long GRB localized by INTEGRAL
  16. GRB 090625: Fermi GBM detection
  17. GRB 090618: Correction to GCN 9568
  18. GRB 090617: Suzaku WAM observation of the prompt emission
  19. GRB 090618: Suzaku WAM observation of the prompt emission
  20. GRB 090623: Fermi GBM detection
  21. GRB 090621B: I-band observations from 1.23m CAHA
  22. GRB 090621D: Fermi GBM detection
  23. GRB 090621B: Gemini spectrum of afterglow candidate
  24. GRB 090621C: Fermi GBM detection
  25. GRB 090621B: P60 Observations
  26. GRB 090620: Fermi GBM detecion
  27. Konus-Wind and Konus-RF observations of GRB 090618
  28. GRB 090621B: Swift-BAT refined analysis
  29. GRB 090621B: RTT150 optical observations
  30. GRB 090618: RTT150 optical observations
  31. GRB 090621A: Swift-BAT refined analysis
  32. GRB 090621B: Swift detection of a short hard burst
  33. GRB090618: Spectrum and photometry from 6.0m BTA
  34. GRB 090618: BOAO V-band Observation
  35. GRB 090621: Swift detection of a burst
  36. GRB 090618: Swift-BAT refined analysis
  37. GRB090618: Swift-XRT team refined analysis
  38. GRB 090618: AGILE observations
  39. GRB 090618: LOAO R-band Observation
  40. GRB 090618: Lick/KAST Spectroscopy
  41. GRB 090618: Swift detection of a bright burst with optical afterglow
  42. GRB 090612: Fermi GBM detection
  43. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  44. GRB 090602: Suzaku WAM observation of the prompt emission
  45. RXTE Discovery of Pulsations from SGR 0418+5729
  46. Konus-RF observation of SGR burst 090605A
  47. Discovery of a new soft gamma repeater source, SGR 0418+5729
  48. GRB 090608: Fermi GBM detection
  49. GRB 090607: Swift-BAT refined analysis of the SHB
  50. GRB 090607: Faulkes Telescope North observations
  51. GRB 090607: Swift detection of a burst
  52. GRB 090530B: Suzaku WAM observation of the prompt emission
  53. GRB 090530: RTT150 Optical Observation
  54. GRB 090529A: RTT150 Optical Observations
  55. GRB 090528: Suzaku WAM observation of the prompt emission
  56. GRB 090528B: Suzaku WAM observation of the prompt emission
  57. GRB090529B: ROVOR Upper Limits
  58. GRB 090531B: Swift/BAT spectral lag results
  59. GRB 090529C: Fermi GBM detection
  60. GRB 090529B: Fermi GBM detection
  61. GRB 090531B, RIMOTS optical upper limits
  62. GRB 090529: MITSuME optical observation
  63. GRB 090531B: Swift-BAT refined analysis
  64. GRB 090531B: Swift detection of a burst
  65. GRB 090531: Swift-BAT refined analysis
  66. GRB090530: R-band Observation
  67. GRB 090531: Swift detection of a burst
  68. GRB 090529: NOT optical observations
  69. GRB 090530: Swift-BAT refined analysis
  70. GRB 090530: GRAS002 refined OA analysis
  71. GRB 090530: PAIRITEL NIR Detections
  72. GRB 090530: Swift detection of a burst with an optical counterpart
  73. GRB 090529: optical observations
  74. GRB 090529: TLS Afterglow Observations
  75. GRB 090529: Swift-BAT refined analysis
  76. GRB 090529: Swift detection of a burst
  77. GRB 090520D: Fermi GBM detection
  78. GRB 090520C: Fermi GBM detection
  79. GRB 090520B: Fermi GBM detection
  80. GRB 090522 : Fermi GBM detection
  81. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  82. GRB 090513B: Fermi GBM detection
  83. GRB 090518: Fermi GBM detection
  84. GRB 090516C: Fermi GBM detection
  85. GRB 090520 Swift-BAT detection of a burst in ground analysis
  86. GRB 090516B: Fermi GBM detection
  87. GRB 090519: Swift-XRT refined analysis
  88. GRB 090519: GROND observation
  89. GRB 090519: Swift/UVOT Upper Limits
  90. GRB 090519, Swift-BAT refined analysis
  91. GRB 090519: TAROT Calern observatory optical observations
  92. GRB 090519: Swift detection of a burst
  93. GRB 090511: Fermi GBM Detection
  94. GRB 090514: Fermi GBM detection
  95. GRB 090518, Swift-BAT refined analysis
  96. GRB 090516, RIMOTS optical upper limits
  97. GRB090513: Fermi GBM detection
  98. GRB 090518: Swift detection of a burst
  99. GRB 090516: Swift-BAT refined analysis
  100. GRB 090516 - Zadko Telescope observations

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