Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

18786 results found.

  1. GRB 050215b: XRT confirmation of IR afterglow candidate
  2. GRB050215b: P60 Optical Observations
  3. GRB 050215b: Swift XRT Source Variability
  4. GRB 050215B: candidate afterglow
  5. GRB 050215b : Lulin follow-up observation
  6. GRB 050215b, BOOTES-2 simultaneous optical observations
  7. GRB 050215B: UKIRT K-band imaging
  8. GRB 050215b: Swift XRT Observations
  9. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  10. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  11. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  12. GRB050215B: ROTSE-III optical observations
  13. GRB050215A: ROTSE-III Optical Observations
  14. short/hard GRB 050202, optical observations
  15. GRB 050128: Radio observations
  16. Further analysis of the short Swift-BAT GRB 050202
  17. GRB 050202: Second epoch radio observations
  18. GRB050202: Radio Observations
  19. GRB 050202: Short burst detected by Swift-BAT
  20. SGR1806-20: Swift-BAT detection of a large normal burst
  21. GRB050128: Faulkes Telescope South observations
  22. GRB050128,optical observations
  23. GRB050126: Updated Swift XRT Position
  24. GRB 050126: Radio Observations
  25. GRB050128 Swift-BAT observations
  26. GRB 050128: Swift XRT prompt afterglow position
  27. GRB 050124: K-band afterglow observations
  28. GRB050126: MASTER optical limit for KECK OT
  29. GRB050126: Burst Parameters Measured by BAT
  30. GRB050126: MASTER optical observations
  31. GRB 050126: Prompt XRT detection and localization
  32. GRB050124: No Swift UVOT Detection of Afterglow Emission
  33. GRB 050117a: Radio Observations
  34. GRB050124,optical observation
  35. GRB050124: Updated Swift XRT Position and Fluxes
  36. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  37. GRB050124: Refined BAT position, spectral and fluence information
  38. GRB050124: Swift-BAT position of a double-peaked burst
  39. GRB050117a: Radio Observations
  40. GRB050117a: Refined analysis
  41. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  42. GRB050117b: Swift-BAT detection of a weak burst
  43. GRB050117: optical observation
  44. GRB 050117, I-band observations
  45. GRB 050117: Optical observation
  46. GRB050117: Refined XRT position
  47. GRB050117: MASTER optical observations
  48. MASTER:GRB050117 SWIFT
  49. GRB050117: Swift-BAT detection of a long multi-peaked burst
  50. GRB050117: Swift XRT Position
  51. SGR1806-20: Swift-BAT observations of two additional bursts
  52. SGR 1806-20, RHESSI observations of the 041227 giant flare
  53. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  54. GRB 041217: Optical observations
  55. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  56. GRB041228: ROTSE-III Optical Observations
  57. GRB041228: Swift-BAT detection of a burst
  58. GRB041219; RXTE ASM Observations
  59. NIR Observations of GRB 041219
  60. GRB041226: ROTSE-III Optical Observations
  61. GRB041226: Swift-BAT detection of a burst
  62. GRB041223: decay of the afterglow
  63. GRB041224: ROTSE-III Optical Observations
  64. GRB 041223: XRT afterglow spectrum and light curve
  65. GRB 041223 Fluence measured by Swift-BAT
  66. GRB041224: Swift-BAT detection of a soft burst
  67. GRB041223: optical and NIR observations with REM
  68. Swift-BAT Time History of GRB041219
  69. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  70. GRB041223: ROTSE-III Optical Observations
  71. GRB041223: Swift-BAT detection of a bright long burst
  72. GRB041220: Swift-BAT burst
  73. GRB 041219 Optical Observations
  74. GRB041219c: Third Burst in One Day from Swift-BAT
  75. GRB041219b: A Swift-BAT burst
  76. Swift-BAT detection of the bright long burst GRB041219
  77. GRB041217: optical limit 30 min after GRB
  78. GRB041217: Optical Observations
  79. GRB041217: NIR and optical observations with REM
  80. GRB041217: P60 Optical Observations
  81. GRB041217: Infrared Observations
  82. GRB041217: The First GRB Located On-Board Swift
  83. GRB040916: Optical observations
  84. GRB040422: optical and NIR observations at the VLT
  85. GRB040223, improved XMM position
  86. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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