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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"

32531 results found.

  1. GRB060923C: optical limit
  2. GRB060927: optical observations
  3. test of new software, grb
  4. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  5. GRB 060927: Swift/UVOT Optical Observations
  6. GRB 060927: Early color
  7. GRB 060927: Swift XRT Team refined analysis
  8. GRB 060927 optical limit
  9. GRB 060927, Swift-BAT refined analysis
  10. GRB060926: improved redshift
  11. GRB 060927, optical observation
  12. GRB 060927: Possible host galaxy (star?) in the SDSS
  13. GRB060927: Faulkes Telescope South observation
  14. GRB 060926: MASTER: first minutes decay
  15. GRB 060927: optical afterglow confirmation
  16. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  17. GRB060926: VLT redshift
  18. GRB 060926: Swift-UVOT Detections
  19. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  20. GRB 060926: OPTIMA-Burst -- further observations
  21. GRB 060926: Swift XRT refined analysis
  22. GRB 060926, Swift-BAT refined analysis
  23. GRB 060923A: Radio Observations
  24. GRB 060926: MASTER OT alert observation
  25. GRB 060912A: Redshift of probable host galaxy
  26. GRB 060926: BOOTES-IR observations
  27. GRB060926 OPTIMA-Burst optical observation
  28. GRB 060926: MASTER optical observation
  29. GRB 060923C, Swift-BAT refined analysis
  30. GRB 060923C: VLA Observation
  31. GRB 060923C: NIR afterglow confirmed
  32. GRB060923C: AROMA optical obsevation
  33. GRB 060923C: Gemini Observations and Afterglow Candidate
  34. GRB 060923C, optical observation
  35. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  36. GRB 060923C: VLT J-band observations
  37. GRB060923B: Swift/UVOT upper limits
  38. GRB 060923B: Swift XRT Refined Analysis
  39. GRB 060923C: Swift XRT refined analysis
  40. GRB 060923C, Swift-BAT partial refined analysis
  41. GRB 060923A: Swift XRT refined analysis
  42. GRB 060923C: Keck Observations
  43. GRB 060923A: Keck and Gemini Observations
  44. GRB 060923B, Swift-BAT refined analysis
  45. GRB060923C : Faulkes Telescope South optical limits
  46. GRB060923C: Faulkes Telescope North optical observations
  47. GRB 060923C: optical observation
  48. GRB 060923, Swift-BAT refined analysis
  49. GRB 060923: Early Super-LOTIS Observations
  50. GRB 060923: UKIRT nIR observations - candidate afterglow
  51. GRB060923: Faulkes Telescope North optical observations
  52. GRB060923 - SDSS Pre-Burst Observations
  53. GRB 060923: KAIT observations
  54. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  55. GRB060919: Swift/UVOT optical observations
  56. GRB 060919 : Faulkes South Telescope Observations
  57. GRB 060919, Swift-BAT refined analysis
  58. GRB060919: XRT refined analysis
  59. GRB 060912A: VLA Observation
  60. GRB 060912A: Probable Host Galaxy
  61. GRB060825: MAGIC telescope GeV observation
  62. Konus-Wind observation of GRB 060912
  63. GRB 060912: Redshift of nearby 2MASS galaxy
  64. GRB060912: optical observations
  65. GRB060912: Swift/UVOT Observations
  66. GRB060912: OPTIMA-Burst optical observations
  67. GRB 060912: Swift XRT Team Refined Analysis
  68. GRB 060912, Swift-BAT refined analysis
  69. GRB 060912: Correction to GCN 5559
  70. VLA observations of GRB 060908
  71. GRB 060908: redshift
  72. GRB 060908, Swift/XRT refined analysis
  73. GRB 060908: Swift/UVOT Observations
  74. GRB 060908: Danish/DFOSC optical observations
  75. GRB 060908, Swift-BAT refined analysis
  76. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  77. GRB 060908: REM optical prompt observation
  78. GRB 060904A: Suzaku/WAM observation of the prompt emission
  79. GRB060906 , optical observation
  80. GRB060904b optical detections (delayed report due to internet outage)
  81. GRB 060906: optical observation
  82. GRB 060906: Early RAPTOR optical limits
  83. GRB 060906, Swift-BAT refined spectral analysis
  84. GRB 060906: Swift/XRT Refined Analysis
  85. GRB 060906: Swift-UVOT observations
  86. VLT redshift of GRB 060906
  87. GRB 060906, Swift-BAT refined analysis
  88. GRB 060906: FRAM observations - flash determination (airplane)
  89. GRB 060906: KAIT observations
  90. GRB 060906: Confirmation of P60 Optical Afterglow
  91. GRB 060906: observations with FRAM
  92. GRB 060904A Milagro GeV/TeV Observations
  93. GRB060904b, optical observations
  94. GRB 060904b: SMARTS optical/IR afterglow observations
  95. GRB 060904B: RTT150 optical observations
  96. GRB060904A: Swift/UVOT optical observations
  97. GRB 060904A: Subaru NIR observation
  98. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  99. GRB 060904B: Swift-BAT refined analysis
  100. GRB060904b: Optical observations with Swift/UVOT

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