Skip to main content
New! BOOM Notices and Schema v7.0.0. 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. XRT observations of GRB 051105A
  2. GRB 051105: Swift-BAT improved refined analysis
  3. GRB 051105b: ART optical limits
  4. GRB051105B - A long GRB detected by INTEGRAL
  5. GRB 051105B (INTEGRAL 2701): Optical observation
  6. GRB 051105: Swift-BAT refined analysis
  7. GRB 051105: Optical limit
  8. GRB 051105: Swift detection of a short burst
  9. IBAS Alert 2700: Not a GRB
  10. GRB 051016B host spectroscopy and redshift
  11. GRB051016B: optical observation
  12. Recent GRB UBVRcIc field photometry
  13. Konus-Wind observation of GRB 051028
  14. GRB051028:MASTER correction and final results
  15. GRB 051022: RTT150 optical observations
  16. GRB 051021A: RTT150 optical observations
  17. GRB051028 SARA Observation
  18. GRB051028: optical observations
  19. GRB051028: Swift/UVOT upper limits
  20. GRB051028: confirmation of the afterglow
  21. GRB051028: WHT optical candidate
  22. GRB051028: Swift XRT Position
  23. GRB051028:MASTER observations
  24. GRB 051028 (=H3951): A GRB localized by HETE
  25. GRB051028:MASTER optical observations
  26. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  27. GRB051022: Swift XRT measurement of jet break
  28. SGR 1806-20: continued moderate activity seen with INTEGRAL
  29. GRB051021B: Swift/UVOT Upper limits
  30. GRB 051021, Optical Observations
  31. GRB 051022: XRT Refined Spectral and Temporal Analysis
  32. GRB 051022, refined optical astrometry
  33. Chandra Observations of GRB 051022
  34. GRB051012: Swift-XRT analysis
  35. GRB 051022 Chandra Observations scheduled
  36. GRB051021B: Swift XRT refined analysis
  37. GRB051021a: optical observations
  38. GRB 051022: WSRT Radio Detection
  39. GRB 051022, mm counterpart
  40. GRB051022: host galaxy redshift
  41. GRB 051022: Swift/UVOT Upper Limits
  42. GRB051022: Radio Counterpart
  43. GRB051022: IR observations
  44. GRB 051022: SOAR JKs Observations
  45. GRB051021A: Swift XRT refined analysis
  46. Konus-Wind observation of GRB 051022
  47. GRB051022: Optical Observations
  48. GRB 051022: Magellan NIR imaging
  49. GRB 051021: PROMPT RcIc Observations
  50. GRB051021b: Magellan IR Imaging
  51. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  52. GRB 051021: Correction
  53. GRB 051022, J & K-band observation
  54. GRB 051021, SMARTS optical/IR observations
  55. GRB051022: Swift XRT Position
  56. GRB 051021: P200 Ks Observations
  57. IPN triangulation of GRB051022 (=H3950)
  58. GRB 051021: MDM Upper Limit
  59. GRB 051022 (=H3950): SXC Flight Localization is Valid
  60. GRB051021: Swift/UVOT Upper Limits
  61. GRB 051021B: Refined analysis of the Swift-BAT burst
  62. GRB 051022: SSO40 Optical Observations
  63. GRB051022,optical observation
  64. GRB 051022A: ROTSE-III Optical Limits
  65. GRB051022 (=H3590), A GRB Detected By HETE
  66. GRB 051022: Optical observations
  67. GRB 051021,optical observation
  68. GRB051021B: Swift XRT Position
  69. GRB 051021: SOAR NIR Observations
  70. GRB 051021B: Swift detection of a burst
  71. GRB051021: Swift XRT analysis
  72. GRB051021 (=H3947): Refined Analysis
  73. GRB 051021 : optical afterglow observation at Lulin
  74. GRB 051021: Optical observations
  75. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  76. GRB 051021: Optical observations and candidate afterglow
  77. GRB051021.63
  78. GRB051021.6: MASTER optical observation
  79. Swift-BAT trigger 160640 is not a real GRB
  80. GRB051021: A GRB Localized by HETE
  81. Swift-BAT trigger 160619 is not a GRB
  82. Swift-BAT triggered on a posible CR Shower or possible GRB
  83. GRB 050502b: Optical limit
  84. GRB 051016b: Optical limit
  85. Afterglow candidate of GRB 051016B observed at Lulin
  86. GRB 051016b: Gemini Near IR Observations
  87. GRB 051016A: Swift/UVOT upper limits
  88. GRB 051016B: refined analysis of the Swift/XRT data
  89. GRB 051016B: Swift/UVOT detection
  90. GRB 051016B,optical observation
  91. GRB 051016B : Optical follow-up at Lulin
  92. GRB 051016B: Refined analysis of the Swift-BAT burst
  93. GRB 051016B: Swift detection of a soft burst
  94. GRB 051016: Swift-BAT refined analysis
  95. GRB051016 XMM-Newton observation
  96. GRB051016: Swift XRT refined analysis.
  97. GRB051016: Planned XMM-Newton observation
  98. GRB 051016: LCO optical and near-IR imaging
  99. GRB 051016: PROMPT Observations
  100. GRB051016: Swift detection of a burst

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