Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

19175 results found.

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