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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. GRB060926 OPTIMA-Burst optical observation
  2. GRB 060926: MASTER optical observation
  3. GRB 060926: Swift detection of a burst
  4. GRB 060923C, Swift-BAT refined analysis
  5. GRB 060923C: VLA Observation
  6. GRB 060923C: NIR afterglow confirmed
  7. GRB060923C: AROMA optical obsevation
  8. GRB 060923C: Gemini Observations and Afterglow Candidate
  9. GRB 060923C, optical observation
  10. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  11. GRB 060923C: VLT J-band observations
  12. GRB060923B: Swift/UVOT upper limits
  13. GRB 060923B: Swift XRT Refined Analysis
  14. GRB 060923C: Swift XRT refined analysis
  15. GRB 060923C, Swift-BAT partial refined analysis
  16. GRB 060923A: Swift XRT refined analysis
  17. GRB 060923C: Keck Observations
  18. GRB 060923A: Keck and Gemini Observations
  19. GRB 060923C: Xinglong TNT optical observations
  20. GRB 060923B, Swift-BAT refined analysis
  21. GRB060923C : Faulkes Telescope South optical limits
  22. GRB060923C: Faulkes Telescope North optical observations
  23. GRB 060923C: optical observation
  24. GRB 060923C: Swift detection of a burst
  25. GRB 060923B: Swift detection of a burst
  26. GRB 060923, Swift-BAT refined analysis
  27. GRB 060923: Early Super-LOTIS Observations
  28. GRB 060923: UKIRT nIR observations - candidate afterglow
  29. GRB060923: Faulkes Telescope North optical observations
  30. GRB060923 - SDSS Pre-Burst Observations
  31. GRB 060923: KAIT observations
  32. GRB 060923: Swift detection of a burst
  33. Swift detection of IGR J17497-2821 (trigger 230504)
  34. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  35. GRB060919: Swift/UVOT optical observations
  36. GRB 060919 : Faulkes South Telescope Observations
  37. GRB 060919, Swift-BAT refined analysis
  38. GRB060919: XRT refined analysis
  39. GRB 060919: TAROT optical observations
  40. GRB 060919: Swift detection of a burst
  41. GRB 060912A: VLA Observation
  42. GRB 060912A: Probable Host Galaxy
  43. IBAS Alert n.3470: not a GRB
  44. GRB060825: MAGIC telescope GeV observation
  45. Konus-Wind observation of GRB 060912
  46. IBAS Alert No.3468: not a GRB
  47. GRB 060912: Redshift of nearby 2MASS galaxy
  48. GRB060912: optical observations
  49. GRB 060912B: Watcher observations
  50. GRB060912: Swift/UVOT Observations
  51. GRB060912: OPTIMA-Burst optical observations
  52. GRB 060912B: a long GRB detected with INTEGRAL
  53. GRB 060912: Swift XRT Team Refined Analysis
  54. GRB 060912, Swift-BAT refined analysis
  55. GRB 060912: Correction to GCN 5559
  56. GRB 060912: Xinglong TNT optical observations
  57. GRB 060912: Swift detection of a burst with an optical afterglow
  58. GRB060906: Danish/DFOSC optical observations
  59. VLA observations of GRB 060908
  60. GRB 060908: redshift
  61. GRB 060908, Swift/XRT refined analysis
  62. GRB 060908: Swift/UVOT Observations
  63. GRB 060908: Danish/DFOSC optical observations
  64. GRB 060908, Swift-BAT refined analysis
  65. GRB 060908 - SDSS Pre-burst Observations
  66. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  67. GRB 060904B: Kiso Optical observation
  68. GRB 060904A : Optical limit
  69. GRB 060908: REM optical prompt observation
  70. GRB 060908: PROMPT Detection of a Bright Counterpart
  71. GRB 060908: Swift detection of a burst with a bright optical counterpart
  72. GRB 060904A: Suzaku/WAM observation of the prompt emission
  73. GRB060906 , optical observation
  74. GRB060904b optical detections (delayed report due to internet outage)
  75. GRB 060906: optical observation
  76. GRB 060906: Early RAPTOR optical limits
  77. GRB 060906, Swift-BAT refined spectral analysis
  78. GRB 060906: Swift/XRT Refined Analysis
  79. GRB 060906: Swift-UVOT observations
  80. VLT redshift of GRB 060906
  81. GRB 060906, Swift-BAT refined analysis
  82. GRB 060906: FRAM observations - flash determination (airplane)
  83. GRB 060906: KAIT observations
  84. GRB 060906: Confirmation of P60 Optical Afterglow
  85. GRB 060906: observations with FRAM
  86. GRB 060906 (?): P60 Optical Afterglow Candidate
  87. GRB 060906: Swift detection of a probable burst
  88. GRB 060904A Milagro GeV/TeV Observations
  89. GRB060904b, optical observations
  90. GRB 060904b: SMARTS optical/IR afterglow observations
  91. GRB 060904B: RTT150 optical observations
  92. GRB060904A: Swift/UVOT optical observations
  93. GRB 060904A: Subaru NIR observation
  94. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  95. GRB 060904B: Swift-BAT refined analysis
  96. GRB060904b: Optical observations with Swift/UVOT
  97. Konus-Wind observation of GRB 060904A
  98. GRB 060904B: Swift-XRT refined analysis
  99. GRB 060904A: Refined analysis of the Swift-BAT burst
  100. GRB 060904A: Swift-XRT refined analysis

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