Skip to main content
Retirement of GCN Classic VOEvent Brokers. 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 091127: Suzaku WAM observation of the prompt emission
  2. GRB 091126: Fermi GBM detection
  3. GRB 091130B: Swift-XRT team refined analysis
  4. GRB 091130B: Swift-BAT refined analysis
  5. GRB 091130B: Swift/UVOT Upper Limits
  6. GRB 091127: Skynet/PROMPT Observations of Fading
  7. GRB 091130B: Enhanced Swift-XRT position
  8. Swift trigger 377436 (possible GRB 091130A) is not a burst
  9. GRB 091130B: MASTER observations
  10. GRB 091130B: SDSS galaxy at XRT location
  11. GRB 091130B: Swift detection of a burst
  12. GRB 091130: MASTER observations
  13. GRB 091130: Swift detection of a possible burst
  14. GRB 091127: Radio observations
  15. GRB 091128: Fermi GBM detection
  16. Konus-Wind observation of GRB 091127
  17. GRB 091127: TAROT La Silla observatory optical observations
  18. GRB 091127: optical observations
  19. GRB 091127: LABOCA/APEX submm observations
  20. GRB 091127: Further NOT optical observations
  21. GRB 091127: Fermi GBM detection
  22. GRB 091127: MASTER early optical transient polarimetry
  23. GRB 091127: Gemini-N redshift
  24. GRB 091127: Swift-XRT afterglow detection and analysis
  25. GRB 091127: TAROT La Silla observatory optical decay
  26. GRB 091127: Swift/UVOT observations
  27. GRB 091127: CAHA 1.23m I-band observations
  28. GRB 091127: Swift-BAT refined analysis
  29. GRB 091127: NOT observations
  30. GRB 091127 : GROND observations
  31. GRB 091127: REM NIR afterglow detection
  32. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  33. GRB 091127: Liverpool Telescope afterglow candidate
  34. GRB 091127: Swift detection of a burst
  35. IPN Triangulation of GRB091120
  36. Konus-Wind observation of GRB 091120
  37. GRB 091120: MAXI GSC detection
  38. GRB 091120: Fermi GBM observation
  39. GRB 091117A: Suzaku WAM observation of the prompt emission
  40. GRB 091117: TNG optical observations
  41. GRB 091117A: Swift/UVOT followup observations
  42. GRB 091117: 2nd epoch of Magellan optical observations
  43. GRB 091117: VLA radio observations
  44. GRB 091117: Swift-XRT observations
  45. GRB 091117 BAT refined analysis
  46. GRB 091117: Evidence for Variability of XRT Source #1
  47. GRB091117: Gemini South Observations
  48. GRB 091117: Swift XRT refined analysis
  49. GRB 091117: Gemini-North spectroscopy of DSS galaxy
  50. Konus-Wind observations of GRB 091117A
  51. GRB 091117: Magellan optical observations
  52. GRB 091117: XRT source coincident with a DSS galaxy
  53. GRB 091117: OSN I-band observations
  54. GRB 091117A Detected in ground analysis of BAT data and IPN triangulation
  55. GRB 091112: Suzaku WAM observation of the prompt emission
  56. GRB 091102A: Suzaku WAM observation of the prompt emission
  57. GRB 091109B: Suzaku WAM observation of the prompt emission
  58. GRB091111: Swift XRT refined analysis
  59. Konus-Wind and Konus-RF observations of GRB 091031
  60. GRB 091112: Swift-BAT refined analysis
  61. GRB 091112: Fermi GBM observation
  62. GRB 091031: Fermi LAT detection of a faint burst
  63. GRB 091112: Swift detection of a possible burst
  64. GRB 091111: BOOTES-3 contemporaneous imaging
  65. GRB 091111: BOOTES-3 observations
  66. GRB 091111: a faint long GRB detected with INTEGRAL
  67. GRB 091109A: GROND and VLT observations
  68. GRB 091109B: Swift/UVOT Upper Limits
  69. GRB 091109B: VLT afterglow confirmation
  70. GRB 091109B: Swift-XRT Team refined analysis
  71. GRB 091109B: VLT observations
  72. GRB 091109b: Magellan Observations
  73. GRB 091109B: Swift-BAT refined analysis
  74. GRB 091109B: Enhanced Swift-XRT position
  75. GRB 091109B: Optical limits from Watcher
  76. GRB 091109B: ROTSE-III Optical Limits
  77. GRB 091109B: Swift detection of a short burst
  78. GRB091109: Correction to GCN 10139
  79. GRB 091030: Fermi GBM detection
  80. GRB 091109: Swift-XRT refined analysis
  81. GRB 091109: BOOTES-3 observations
  82. GRB 091109: Swift/UVOT observations
  83. GRB 091109: Faulkes Telescope South observations
  84. GRB 091109: Swift-BAT refined analysis
  85. GRB 091109: Enhanced Swift-XRT position
  86. GRB091109: REM detection of the NIR afterglow
  87. GRB 091109: Swift detection of a burst with optical afterglow
  88. GRB 091029: Observations from Stardome Observatory
  89. GRB 091104: Swift-BAT refined analysis
  90. GRB 091104: Swift XRT Refined Analysis
  91. GRB 091104: Swift/UVOT Upper Limits
  92. GRB091026 : IRSF NIR upper limit
  93. GRB091102 : MOA optical upper limit
  94. GRB 091104: Enhanced Swift-XRT position
  95. GRB 091104: Swift detection of a burst
  96. GRB 091102: LABOCA/APEX submm observations
  97. Fermi LAT Upper Limits on GRB 091010
  98. GRB 091102 : Faulkes Telescope South Upper Limits
  99. GRB 091102A: Fermi GBM observation
  100. GRB 091102: Swift-XRT refined analysis

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