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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 060923: Early Super-LOTIS Observations
  2. GRB 060923: UKIRT nIR observations - candidate afterglow
  3. GRB060923: Faulkes Telescope North optical observations
  4. GRB060923 - SDSS Pre-Burst Observations
  5. GRB 060923: KAIT observations
  6. GRB 060923: Swift detection of a burst
  7. Swift detection of IGR J17497-2821 (trigger 230504)
  8. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  9. GRB060919: Swift/UVOT optical observations
  10. GRB 060919 : Faulkes South Telescope Observations
  11. GRB 060919, Swift-BAT refined analysis
  12. GRB060919: XRT refined analysis
  13. GRB 060919: TAROT optical observations
  14. GRB 060919: Swift detection of a burst
  15. GRB 060912A: VLA Observation
  16. GRB 060912A: Probable Host Galaxy
  17. IBAS Alert n.3470: not a GRB
  18. GRB060825: MAGIC telescope GeV observation
  19. Konus-Wind observation of GRB 060912
  20. IBAS Alert No.3468: not a GRB
  21. GRB 060912: Redshift of nearby 2MASS galaxy
  22. GRB060912: optical observations
  23. GRB 060912B: Watcher observations
  24. GRB060912: Swift/UVOT Observations
  25. GRB060912: OPTIMA-Burst optical observations
  26. GRB 060912B: a long GRB detected with INTEGRAL
  27. GRB 060912: Swift XRT Team Refined Analysis
  28. GRB 060912, Swift-BAT refined analysis
  29. GRB 060912: Correction to GCN 5559
  30. GRB 060912: Xinglong TNT optical observations
  31. GRB 060912: Swift detection of a burst with an optical afterglow
  32. GRB060906: Danish/DFOSC optical observations
  33. VLA observations of GRB 060908
  34. GRB 060908: redshift
  35. GRB 060908, Swift/XRT refined analysis
  36. GRB 060908: Swift/UVOT Observations
  37. GRB 060908: Danish/DFOSC optical observations
  38. GRB 060908, Swift-BAT refined analysis
  39. GRB 060908 - SDSS Pre-burst Observations
  40. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  41. GRB 060904B: Kiso Optical observation
  42. GRB 060904A : Optical limit
  43. GRB 060908: REM optical prompt observation
  44. GRB 060908: PROMPT Detection of a Bright Counterpart
  45. GRB 060908: Swift detection of a burst with a bright optical counterpart
  46. GRB 060904A: Suzaku/WAM observation of the prompt emission
  47. GRB060906 , optical observation
  48. GRB060904b optical detections (delayed report due to internet outage)
  49. GRB 060906: optical observation
  50. GRB 060906: Early RAPTOR optical limits
  51. GRB 060906, Swift-BAT refined spectral analysis
  52. GRB 060906: Swift/XRT Refined Analysis
  53. GRB 060906: Swift-UVOT observations
  54. VLT redshift of GRB 060906
  55. GRB 060906, Swift-BAT refined analysis
  56. GRB 060906: FRAM observations - flash determination (airplane)
  57. GRB 060906: KAIT observations
  58. GRB 060906: Confirmation of P60 Optical Afterglow
  59. GRB 060906: observations with FRAM
  60. GRB 060906 (?): P60 Optical Afterglow Candidate
  61. GRB 060906: Swift detection of a probable burst
  62. GRB 060904A Milagro GeV/TeV Observations
  63. GRB060904b, optical observations
  64. GRB 060904b: SMARTS optical/IR afterglow observations
  65. GRB 060904B: RTT150 optical observations
  66. GRB060904A: Swift/UVOT optical observations
  67. GRB 060904A: Subaru NIR observation
  68. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  69. GRB 060904B: Swift-BAT refined analysis
  70. GRB060904b: Optical observations with Swift/UVOT
  71. Konus-Wind observation of GRB 060904A
  72. GRB 060904B: Swift-XRT refined analysis
  73. GRB 060904A: Refined analysis of the Swift-BAT burst
  74. GRB 060904A: Swift-XRT refined analysis
  75. GRB 060904A: Suzaku-XIS and -HXD observation plan
  76. GRB 060904B: VLT redshift
  77. GRB 060904A: P60 Observations
  78. GRB 060904B: Optical observations at Crni Vrh
  79. GRB060904B: Watcher observations
  80. GRB 060904B BOOTES-IR and 1.5m OSN observations
  81. GRB 060904B: TAROT optical counterpart observations
  82. GRB060904B - SDSS Pre-Burst Observations
  83. GRB 060904: TAROT optical observations
  84. GRB 060904B: Swift detection of a burst with optical counterpart
  85. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  86. GRB060904 - SDSS Pre-Burst Observations
  87. GRB 060904: Swift detection of a bright burst
  88. GRB060901: Optical observations
  89. 060901: Swift UVOT followup observations
  90. GRB 060901: pseudo-z from spectral parameters of the prompt
  91. Konus-Wind observation of GRB 060901
  92. GRB 060901: SMARTS optical/IR observations update
  93. GRB 060901: Swift/XRT Refined Analysis
  94. GRB 060901: SMARTS optical/IR observations
  95. GRB 060901: Swift/XRT Position
  96. GRB 060901: further INTEGRAL results
  97. GRB 060901: Watcher observations
  98. GRB 060901: a long GRB detected by INTEGRAL
  99. Two bright bursts from SGR 1806-20 detected with IBAS
  100. GRB 060605, observations using an Integral Field Unit

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