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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 090313: optical observations
  2. XRF 090702: VLT imaging
  3. XRF 090702: Swift-XRT afterglow position
  4. XRF 090702: a long soft GRB localized with INTEGRAL
  5. GRB 090404: Deep optical imaging and possible host association (correction)
  6. GRB 090404: Deep optical imaging and possible host association
  7. GRB 090701: Fermi GBM detection
  8. GRB 090628: Swift XRT refined analysis
  9. GRB 090630: Fermi GBM detection
  10. GRB 090618: RTT150 optical observations
  11. GRB 090628: Swift/UVOT Upper Limits
  12. Konus-Wind observation of GRB 090626
  13. GRB080628: SAO RAS optical observations
  14. GRB 090628: Swift-BAT refined analysis
  15. GRB090618: 15GHz radio emission faded
  16. GRB 090628: GROND upper limits
  17. GRB 090628: Enhanced Swift-XRT position
  18. GRB 090628: 1.23m CAHA optical observations
  19. GRB 090626: IPN localization
  20. GRB 090628: Swift/UVOT Finding Chart Observation
  21. GRB 090628: Swift XRT position
  22. GRB 090628: Swift detection of a burst
  23. Fermi LAT observations of GRB 090626
  24. GRB 090625B: Fermi GBM observation
  25. GRB 090423: Spitzer observations of the z~8.3 burst
  26. GRB 090625B: Swift/UVOT Upper Limits
  27. GRB 090625B: Swift-XRT refined analysis
  28. GRB 090626: Fermi GBM detection
  29. GRB 090625B: GROND upper limits
  30. GRB 090623: Suzaku WAM observation of the prompt emission
  31. GRB090618: HCT optical observations
  32. GRB 090618: SARA Second Epoch Observations
  33. GRB 090625B: Faulkes Telescope South observations
  34. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  35. GRB 090625B: a long GRB localized by INTEGRAL
  36. GRB 090625: Fermi GBM detection
  37. GRB 090618: Correction to GCN 9568
  38. GRB 090617: Suzaku WAM observation of the prompt emission
  39. GRB 090618: Suzaku WAM observation of the prompt emission
  40. GRB 090621A: Enhanced Swift-XRT position
  41. GRB 090623: Fermi GBM detection
  42. GRB 090621B: GRT Optical Observation
  43. GRB 090621A: GRT Optical Observation
  44. PAIRITEL observations of GRB 090618
  45. GRB 090621B: Fermi GBM detection
  46. GRB 090621B: I-band observations from 1.23m CAHA
  47. GRB 090621D: Fermi GBM detection
  48. GRB 090621B: Gemini spectrum of afterglow candidate
  49. GRB 090621C: Fermi GBM detection
  50. GRB 090621B: P60 Observations
  51. GRB 090621: Fermi GBM observation
  52. GRB 090621B: VLA observations
  53. GRB 090620: Fermi GBM detecion
  54. Konus-Wind and Konus-RF observations of GRB 090618
  55. GRB 090621B: Swift/UVOT Upper Limits
  56. GRB 090621B: Swift-BAT refined analysis
  57. GRB 090621B: Swift-XRT refined analysis
  58. GRB 090621B: RTT150 optical observations
  59. GRB 090618: RTT150 optical observations
  60. GRB 090621B: Optical Observations
  61. GRB 090621A: Swift-BAT refined analysis
  62. GRB 090621B: Swift detection of a short hard burst
  63. GRB 090621: Swift/UVOT Upper Limits
  64. GRB 090621: Swift-XRT Team refined analysis
  65. GRB090618: Spectrum and photometry from 6.0m BTA
  66. GRB 090618: BOAO V-band Observation
  67. GRB 090621: Swift detection of a burst
  68. GRB 090618: ZTSh optical observations
  69. GRB 090618 : WSRT radio detection
  70. GRB090618, underlying supernova search
  71. GRB090618: OAA-OAUV Optical observations
  72. GRB 090618: Fermi GBM observation
  73. GRB 090618, Swift-BAT refined spectral analysis
  74. VLA radio detection of GRB 090618
  75. GRB 090618 15GHz radio detection
  76. GRB090618 - Continued optical monitoring and light curve break
  77. GRB 090618: Swift-BAT refined analysis
  78. GRB 090618: SARA observations
  79. GRB090618: Swift-XRT team refined analysis
  80. GRB090618: Swift/UVOT bright afterglow detection
  81. GRB 090618: SDSS host detection
  82. Swift XRT observations of GRB 090531A
  83. GRB 090618: AGILE observations
  84. GRB 090617: Fermi GBM detection
  85. GRB 090618: LOAO R-band Observation
  86. GRB 090618: Enhanced Swift-XRT position
  87. GRB 090618 Faulkes Telescope North observations
  88. Optical observations of GRB 090618
  89. GRB 090618: Lick/KAST Spectroscopy
  90. GRB 090618: OA behavior from KAIT
  91. GRB 090618: planned XMM-Newton observation
  92. GRB 090618: ROTSE-III Detection of Optical Counterpart
  93. GRB 090618: KAIT optical afterglow
  94. GRB090618: P60 Optical Afterglow
  95. GRB 090618: Swift detection of a bright burst with optical afterglow
  96. GRB 090616: Fermi GBM detection
  97. GRB 090612: Fermi GBM detection
  98. GRB 090610C: Fermi GBM detection
  99. GRB 090610B: Fermi GBM detection
  100. GRB 090610: Fermi GBM detection

Advanced

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