Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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. GRB051021: Swift XRT analysis
  2. GRB051021 (=H3947): Refined Analysis
  3. GRB 051021 : optical afterglow observation at Lulin
  4. GRB 051021: Optical observations
  5. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  6. GRB 051021: Optical observations and candidate afterglow
  7. GRB051021.63
  8. GRB051021.6: MASTER optical observation
  9. Swift-BAT trigger 160640 is not a real GRB
  10. GRB051021: A GRB Localized by HETE
  11. Swift-BAT trigger 160619 is not a GRB
  12. Swift-BAT triggered on a posible CR Shower or possible GRB
  13. GRB 050502b: Optical limit
  14. GRB 051016b: Optical limit
  15. Afterglow candidate of GRB 051016B observed at Lulin
  16. GRB 051016b: Gemini Near IR Observations
  17. GRB 051016A: Swift/UVOT upper limits
  18. GRB 051016B: refined analysis of the Swift/XRT data
  19. GRB 051016B: Swift/UVOT detection
  20. GRB 051016B,optical observation
  21. GRB 051016B : Optical follow-up at Lulin
  22. GRB 051016B: Refined analysis of the Swift-BAT burst
  23. GRB 051016B: Swift detection of a soft burst
  24. GRB 051016: Swift-BAT refined analysis
  25. GRB051016 XMM-Newton observation
  26. GRB051016: Swift XRT refined analysis.
  27. GRB051016: Planned XMM-Newton observation
  28. GRB 051016: LCO optical and near-IR imaging
  29. GRB 051016: PROMPT Observations
  30. GRB051016: Swift detection of a burst
  31. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  32. GRB051006: optical observations
  33. GRB 051012: Swift-BAT detection of burst yesterday
  34. Swift trigger 159578 is not a burst
  35. Swift-BAT Trigger 159578 is a possible burst
  36. GRB050805A: Rc optical observations
  37. GRB 051006: Swift/UVOT Upper Limits
  38. IBAS Alert 2675 : not a GRB
  39. GRB051008: optical candidate
  40. GRB 051008: - a high redshift high-luminosity burst?
  41. GRB 051008 - a low redshift low-luminosity burst?
  42. IBAS Alert 2673: not a real GRB
  43. GRB051011: bright nebulae near error box
  44. GRB051011: MASTER optical observation
  45. GRB051008: optical observation
  46. GRB051008: Swift XRT refined analysis
  47. GRB051008 - Swift UVOT upper limits
  48. Konus-Wind observation of GRB 051008
  49. GRB051008: Final refined analysis of the Swift-BAT burst
  50. GRB 051008: R-band upper limit
  51. GRB051008: Refined analysis of the Swift-BAT burst
  52. GRB051008: Radio Observation
  53. GRB 051008: Swift XRT position
  54. GRB 051008, optical observations
  55. GRB 051008: early Swift XRT analysis
  56. GRB 051008: Swift UVOT Candidate
  57. GRB051008: Swift-BAT detection of a bright burst
  58. GRB 051006: P60 Observations
  59. grb test
  60. GRB 051006: XRT refined analysis
  61. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  62. GRB 051006: optical observations at Sierra Nevada
  63. GRB051006: Refined analysis of the Swift-BAT burst
  64. GRB 051006: XRT position
  65. GRB051006: Swift detection of a burst
  66. GRB 050906, summary of radio observations
  67. Swift-BAT triggers 158261 and 158262 Retraction
  68. GRB051001: Swift UVOT Upper Limits
  69. GRB 050925: Second Epoch WSRT Radio Observations
  70. GRB 051001: Swift XRT refined analysis
  71. GRB 051001, optical observations at Mt. John
  72. GRB 051001: I-band limit
  73. GRB 051001: AAT infra-red observations
  74. GRB 051001: Swift-BAT refined analysis
  75. GRB 051001: Swift Detection of a Burst
  76. GRB 051001: ROTSE-III Optical Limits
  77. GRB050908: optical observations
  78. GRB050922C: optical observation
  79. GRB050922B: optical limit
  80. GRB 050922C: further VLT observations
  81. GRB 050820A: NIR photometry at the TNG
  82. GRB050922C: UVES/VLT high resolution spectroscopy
  83. GRB050925: Swift/XRT limits
  84. GRB/SGR 050925: IR Observations
  85. GRB050922C - Swift UVOT preliminary analysis
  86. GRB 050922C: break in the lightcurve
  87. GRB 050925: WSRT Radio Observations
  88. GRB050925: Swift UVOT upper limits
  89. Refined analysis of the Swift-BAT soft short burst
  90. GRB 050925 : I-band observation at Xinglong observatory
  91. GRB050925: Faulkes Telescope North R-band limit
  92. GRB050925: Swift-BAT detection of a short burst
  93. GRB 050922B: Correction to BAT refined analysis, longer burst
  94. GRB050922C: TNG spectroscopic observations
  95. GRB050922B: refined XRT analysis
  96. Konus-Wind observation of GRB 050922C
  97. GRB 050922C: Refined redshift
  98. GRB050922B: Swift UVOT early upper limits.
  99. GRB OT observation
  100. GRB050922C: observation at MonteBoo

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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