Skip to main content
Updated Client Credential Expiration Policy. 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').
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 060607B: Swift-BAT Refined Analysis
  2. GRB060602A: Swift/UVOT upper limits
  3. GRB 060607B: Swift detection of a burst
  4. GCN 060607: Swift-UVOT obswervations.
  5. GRB 060607: Swift-BAT Refined Analysis
  6. GRB 060607: optical limit by "Pi of the Sky"
  7. GRB 060607: Swift-XRT Team refined analysis
  8. GRB 060607: IR observations
  9. GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst
  10. VLT/UVES observations of GRB 060607
  11. GRB 060607: PROMPT Observations
  12. GRB 060605: RTT150 optical observations
  13. GRB 060607: REM NIR afterglow
  14. GRB 060607: Swift detection of a burst with bright optical counterpart
  15. GRB 060522: PROMPT Optical Limits
  16. GRB 060605 BAT refined analysis
  17. GRB 060605: Xinglong TNT optical observations
  18. GRB060602B : REM infrared observations
  19. GRB060605: Swift/UVOT detections
  20. GRB 060605: Swift-XRT Team refined analysis
  21. SALT spectroscopy of GRB 060605
  22. GRB 060605: TNG optical observations
  23. GRB 060605: RTT150 optical observations
  24. GRB060605: Spectral Observations and Redshift
  25. GRB 060605: ROTSE-III Optical Counterpart
  26. GRB 060605: Swift detection of a burst with optical counterpart
  27. GRB 060605: ROTSE-III Detection of Optical Counterpart
  28. GRB060604: Swift/UVOT detections
  29. GRB 060604: redshift
  30. GRB 060512: Keck Redshift
  31. GRB 060604 optical photometry
  32. GRB 060604: Swift-XRT Team refined analysis
  33. GRB 060604: BAT refined analysis
  34. GRB 060604A: ROTSE-III Optical Limits
  35. GRB 060604: Swift detection of a burst with possible optical counterpart
  36. GRB 060602A: Swift-BAT Refined Analysis: Correction
  37. GRB 060602B: XMM-Newton Survey Source
  38. GRB 060602B: Swift-XRT Refined Analysis
  39. GRB 060602B: Swift-BAT Refined Analysis
  40. GRB 060602B: Swift/UVOT observations
  41. GRB 060602A: Swift-BAT Refined Analysis
  42. GRB 060602B: RTT150 optical observations
  43. GRB 060211A : WIDGET simultaneous optical observations
  44. GRB060602A: optical observations(/transient?)
  45. GRB 060526: Tautenburg Second Epoch Observations
  46. GRB060602A: Bootes-IR observations
  47. GRB 060602B: Swift detection of a burst
  48. GRB060602B: Watcher observations - no OT candidate
  49. GRB060602B: BOOTES-IR candidate afterglow
  50. GRB060602 - SDSS Pre-Burst Observations
  51. GRB 060602: Swift detection of a burst
  52. GRB 060502A: Optical afterglow observations
  53. GRB 060526: Break in X-ray light curve
  54. GRB 060526: RTT150 optical observations
  55. GRB060526, optical observations
  56. GRB 051227 : WIDGET simultaneous optical observations
  57. GRB 051028 : WIDGET pre-trigger limit
  58. GRB 060526: RTT150 optical observations
  59. GRB 060526: Multiple Optical Flares
  60. GRB060526: afterglow fitting and probable jet break
  61. GRB 060526: RTT150 optical observations
  62. GRB060526: Optical counterpart from MIRO
  63. GRB060502b: optical observations
  64. GRB 060526: RTT150 optical observations
  65. GRB 060526: Tautenburg OT observation and light curve fitting
  66. GRB060526: optical observations
  67. GRB 060526: SMARTS optical/IR afterglow observations
  68. GRB060526: possible break in the optical light curve
  69. GRB 060526: REM observations
  70. GRB 060526: RTT150 optical observations, afterglow flattening
  71. GRB 060526: Optical Flare
  72. GRB 060526: MDM-2.4m Observations
  73. GRB 060526: Refined analysis of the Swift-BAT burst
  74. GRB 060526: RTT150 optical observations
  75. GRB060526: Further Swift-UVOT Observations
  76. GRB060526, optical observations
  77. GRB 060526: Magellan Redshift
  78. GRB 060526 Lulin optical observation
  79. GRB 060526: Swift/XRT Team refined analysis
  80. GRB 060526: TNG optical observations
  81. GRB 060526: ROTSE-III Observations of Optical Counterpart
  82. GRB 060526: Watcher Observations
  83. GRB060526 - SDSS Pre-burst Observations
  84. GRB 060526: Continued emission for the Swift burst
  85. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  86. GRB060505: VLT observations of the optical afterglow
  87. GRB 060413 : WIDGET simultaneous optical observations
  88. GRB 060522: Swift/UVOT Observations: Correction
  89. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  90. XMM-Newton observation of GRB060510b
  91. GRB060512: Late-Time P200 Observations
  92. GRB060522: z = 5.11 Keck-LRIS Redshift
  93. GRB 060522: Swift/XRT Team refined analysis
  94. GRB 060522: Swift-BAT Refined Analysis
  95. GRB 060522: REM NIR observations
  96. GRB 060522: TNG optical observations
  97. GRB 060522: Swift detection of a burst with possible optical afterglow
  98. GRB 060512: reanalysis of optical spectra
  99. GRB 060515: NIR observation
  100. GRB 060210: Jet Break in the XRT light curve

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