Skip to main content
GCN at AAS 245, Legacy Circulars Address Retirement. See news and announcements

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').
  1. GRB 060923C: NIR afterglow confirmed
  2. GRB060923C: AROMA optical obsevation
  3. GRB 060923C: Gemini Observations and Afterglow Candidate
  4. GRB 060923C, optical observation
  5. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  6. GRB 060923C: VLT J-band observations
  7. GRB060923B: Swift/UVOT upper limits
  8. GRB 060923B: Swift XRT Refined Analysis
  9. GRB 060923C: Swift XRT refined analysis
  10. GRB 060923C, Swift-BAT partial refined analysis
  11. GRB 060923A: Swift XRT refined analysis
  12. GRB 060923C: Keck Observations
  13. GRB 060923A: Keck and Gemini Observations
  14. GRB 060923C: Xinglong TNT optical observations
  15. GRB 060923B, Swift-BAT refined analysis
  16. GRB060923C : Faulkes Telescope South optical limits
  17. GRB060923C: Faulkes Telescope North optical observations
  18. GRB 060923C: optical observation
  19. GRB 060923C: Swift detection of a burst
  20. GRB 060923B: Swift detection of a burst
  21. GRB 060923, Swift-BAT refined analysis
  22. GRB 060923: Early Super-LOTIS Observations
  23. GRB 060923: UKIRT nIR observations - candidate afterglow
  24. GRB060923: Faulkes Telescope North optical observations
  25. GRB060923 - SDSS Pre-Burst Observations
  26. GRB 060923: KAIT observations
  27. GRB 060923: Swift detection of a burst
  28. Swift detection of IGR J17497-2821 (trigger 230504)
  29. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  30. GRB060919: Swift/UVOT optical observations
  31. GRB 060919 : Faulkes South Telescope Observations
  32. GRB 060919, Swift-BAT refined analysis
  33. GRB060919: XRT refined analysis
  34. GRB 060919: TAROT optical observations
  35. GRB 060919: Swift detection of a burst
  36. GRB 060912A: VLA Observation
  37. GRB 060912A: Probable Host Galaxy
  38. IBAS Alert n.3470: not a GRB
  39. GRB060825: MAGIC telescope GeV observation
  40. Konus-Wind observation of GRB 060912
  41. IBAS Alert No.3468: not a GRB
  42. GRB 060912: Redshift of nearby 2MASS galaxy
  43. GRB060912: optical observations
  44. GRB 060912B: Watcher observations
  45. GRB060912: Swift/UVOT Observations
  46. GRB060912: OPTIMA-Burst optical observations
  47. GRB 060912B: a long GRB detected with INTEGRAL
  48. GRB 060912: Swift XRT Team Refined Analysis
  49. GRB 060912, Swift-BAT refined analysis
  50. GRB 060912: Correction to GCN 5559
  51. GRB 060912: Xinglong TNT optical observations
  52. GRB 060912: Swift detection of a burst with an optical afterglow
  53. GRB060906: Danish/DFOSC optical observations
  54. VLA observations of GRB 060908
  55. GRB 060908: redshift
  56. GRB 060908, Swift/XRT refined analysis
  57. GRB 060908: Swift/UVOT Observations
  58. GRB 060908: Danish/DFOSC optical observations
  59. GRB 060908, Swift-BAT refined analysis
  60. GRB 060908 - SDSS Pre-burst Observations
  61. GRB 060904B : CFHT/WIRCam NIR afterglow observations
  62. GRB 060904B: Kiso Optical observation
  63. GRB 060904A : Optical limit
  64. GRB 060908: REM optical prompt observation
  65. GRB 060908: PROMPT Detection of a Bright Counterpart
  66. GRB 060908: Swift detection of a burst with a bright optical counterpart
  67. GRB 060904A: Suzaku/WAM observation of the prompt emission
  68. GRB060906 , optical observation
  69. GRB060904b optical detections (delayed report due to internet outage)
  70. GRB 060906: optical observation
  71. GRB 060906: Early RAPTOR optical limits
  72. GRB 060906, Swift-BAT refined spectral analysis
  73. GRB 060906: Swift/XRT Refined Analysis
  74. GRB 060906: Swift-UVOT observations
  75. VLT redshift of GRB 060906
  76. GRB 060906, Swift-BAT refined analysis
  77. GRB 060906: FRAM observations - flash determination (airplane)
  78. GRB 060906: KAIT observations
  79. GRB 060906: Confirmation of P60 Optical Afterglow
  80. GRB 060906: observations with FRAM
  81. GRB 060906 (?): P60 Optical Afterglow Candidate
  82. GRB 060906: Swift detection of a probable burst
  83. GRB 060904A Milagro GeV/TeV Observations
  84. GRB060904b, optical observations
  85. GRB 060904b: SMARTS optical/IR afterglow observations
  86. GRB 060904B: RTT150 optical observations
  87. GRB060904A: Swift/UVOT optical observations
  88. GRB 060904A: Subaru NIR observation
  89. GRB 060904A: pseudo-z from spectral parameters of the prompt emission
  90. GRB 060904B: Swift-BAT refined analysis
  91. GRB060904b: Optical observations with Swift/UVOT
  92. Konus-Wind observation of GRB 060904A
  93. GRB 060904B: Swift-XRT refined analysis
  94. GRB 060904A: Refined analysis of the Swift-BAT burst
  95. GRB 060904A: Swift-XRT refined analysis
  96. GRB 060904A: Suzaku-XIS and -HXD observation plan
  97. GRB 060904B: VLT redshift
  98. GRB 060904A: P60 Observations
  99. GRB 060904B: Optical observations at Crni Vrh
  100. GRB060904B: Watcher observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov