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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 060919 : Faulkes South Telescope Observations
  2. GRB 060919, Swift-BAT refined analysis
  3. GRB060919: XRT refined analysis
  4. GRB 060919: TAROT optical observations
  5. GRB 060919: Swift detection of a burst
  6. GRB 060912A: VLA Observation
  7. GRB 060912A: Probable Host Galaxy
  8. IBAS Alert n.3470: not a GRB
  9. GRB060825: MAGIC telescope GeV observation
  10. Konus-Wind observation of GRB 060912
  11. IBAS Alert No.3468: not a GRB
  12. GRB 060912: Redshift of nearby 2MASS galaxy
  13. GRB060912: optical observations
  14. GRB 060912B: Watcher observations
  15. GRB060912: Swift/UVOT Observations
  16. GRB060912: OPTIMA-Burst optical observations
  17. GRB 060912B: a long GRB detected with INTEGRAL
  18. GRB 060912: Swift XRT Team Refined Analysis
  19. GRB 060912, Swift-BAT refined analysis
  20. GRB 060912: Correction to GCN 5559
  21. GRB 060912: Xinglong TNT optical observations
  22. GRB 060912: Swift detection of a burst with an optical afterglow
  23. GRB060906: Danish/DFOSC optical observations
  24. VLA observations of GRB 060908
  25. GRB 060908: redshift
  26. GRB 060908, Swift/XRT refined analysis
  27. GRB 060908: Swift/UVOT Observations
  28. GRB 060908: Danish/DFOSC optical observations
  29. GRB 060908, Swift-BAT refined analysis
  30. GRB 060908 - SDSS Pre-burst Observations
  31. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  32. GRB 060904B: Kiso Optical observation
  33. GRB 060904A : Optical limit
  34. GRB 060908: REM optical prompt observation
  35. GRB 060908: PROMPT Detection of a Bright Counterpart
  36. GRB 060908: Swift detection of a burst with a bright optical counterpart
  37. GRB 060904A: Suzaku/WAM observation of the prompt emission
  38. GRB060906 , optical observation
  39. GRB060904b optical detections (delayed report due to internet outage)
  40. GRB 060906: optical observation
  41. GRB 060906: Early RAPTOR optical limits
  42. GRB 060906, Swift-BAT refined spectral analysis
  43. GRB 060906: Swift/XRT Refined Analysis
  44. GRB 060906: Swift-UVOT observations
  45. VLT redshift of GRB 060906
  46. GRB 060906, Swift-BAT refined analysis
  47. GRB 060906: FRAM observations - flash determination (airplane)
  48. GRB 060906: KAIT observations
  49. GRB 060906: Confirmation of P60 Optical Afterglow
  50. GRB 060906: observations with FRAM
  51. GRB 060906 (?): P60 Optical Afterglow Candidate
  52. GRB 060906: Swift detection of a probable burst
  53. GRB 060904A Milagro GeV/TeV Observations
  54. GRB060904b, optical observations
  55. GRB 060904b: SMARTS optical/IR afterglow observations
  56. GRB 060904B: RTT150 optical observations
  57. GRB060904A: Swift/UVOT optical observations
  58. GRB 060904A: Subaru NIR observation
  59. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  60. GRB 060904B: Swift-BAT refined analysis
  61. GRB060904b: Optical observations with Swift/UVOT
  62. Konus-Wind observation of GRB 060904A
  63. GRB 060904B: Swift-XRT refined analysis
  64. GRB 060904A: Refined analysis of the Swift-BAT burst
  65. GRB 060904A: Swift-XRT refined analysis
  66. GRB 060904A: Suzaku-XIS and -HXD observation plan
  67. GRB 060904B: VLT redshift
  68. GRB 060904A: P60 Observations
  69. GRB 060904B: Optical observations at Crni Vrh
  70. GRB060904B: Watcher observations
  71. GRB 060904B BOOTES-IR and 1.5m OSN observations
  72. GRB 060904B: TAROT optical counterpart observations
  73. GRB060904B - SDSS Pre-Burst Observations
  74. GRB 060904: TAROT optical observations
  75. GRB 060904B: Swift detection of a burst with optical counterpart
  76. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  77. GRB060904 - SDSS Pre-Burst Observations
  78. GRB 060904: Swift detection of a bright burst
  79. GRB060901: Optical observations
  80. 060901: Swift UVOT followup observations
  81. GRB 060901: pseudo-z from spectral parameters of the prompt
  82. Konus-Wind observation of GRB 060901
  83. GRB 060901: SMARTS optical/IR observations update
  84. GRB 060901: Swift/XRT Refined Analysis
  85. GRB 060901: SMARTS optical/IR observations
  86. GRB 060901: Swift/XRT Position
  87. GRB 060901: further INTEGRAL results
  88. GRB 060901: Watcher observations
  89. GRB 060901: a long GRB detected by INTEGRAL
  90. Two bright bursts from SGR 1806-20 detected with IBAS
  91. GRB 060605, observations using an Integral Field Unit
  92. GRB 060604: VLA Observation
  93. GRB 060814: Suzaku/WAM observation of the prompt emission
  94. GRB 060605: VLA Observation
  95. GRB 060707: VLA observation
  96. GRB 060825: VLA observations
  97. GRB 060825: pseudo-z from spectral parameters of the prompt emission
  98. Swift-BAT trigger 226614 is not a GRB
  99. GRB060826 - SDSS Pre-Burst Observations
  100. GRB 060826(?): Swift detection of a possible burst

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