Skip to main content
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"
  1. GRB 050525: observatons of the optical afterglow
  2. GRB050525: ROTSE-III Refined Analysis
  3. GRB 050525 - Very Bright, Not Short
  4. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  5. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  6. XRF050522: NIR observations of XRT candidate
  7. XRF 050522: Swift XRT refined analysis
  8. XRF050522: Radio Observations
  9. Swift/UVOT observation of XRF 050522
  10. GRB 050509A: Further I-band imaging
  11. GRB050522,optical observation
  12. GRB050520,optical observation
  13. XRF 050522: Continued NIR P200 Monitoring
  14. RBO Observations of GRB050522
  15. GRB050509b: optical observations
  16. Recent GRB BVRcIc field photometry
  17. GRB050520: Radio Observations
  18. XRF 050522: Swift XRT observation
  19. XRF050522, BVRcIc field photometry
  20. XRF 050522 : Lulin observations
  21. XRF050522: Optical Observations
  22. XRF050522: Near-infrared Observations
  23. XRF 050522: KAIT observations
  24. XRF 050522 detected with INTEGRAL
  25. GRB 050520: VLT/ULTRACAM observations
  26. Swift UVOT Observations of GRB 050520
  27. GRB 050520: Swift XRT refined analysis
  28. XRF050509C: Chandra Afterglow Detection
  29. XRF 050509c: Swift XRT Upper Limit
  30. XRF050509c: Radio Observations
  31. RBO Observations of GRB050520
  32. GRB 050520: P200 Observations
  33. GRB050520: Liverpool Telescope follow-up
  34. RBO Observations of GRB050520
  35. GRB 050520: TAROT optical limit
  36. GRB 050520: Swift XRT position
  37. GRB 050520: VLT/ULTRACAM observations
  38. GRB 050520: OSN optical observations
  39. GRB 050520: BART optical limit
  40. GRB 050520 - A long GRB detected with INTEGRAL
  41. No Swift-BAT Lightcurves in real-time for next 3 weeks
  42. Swift-BAT trigger 122203 is not a real GRB
  43. XRF 050509C: REM NIR and Optical refined analysis
  44. GRB 050504: Swift XRT afterglow candidate has faded
  45. XRF 050509c optical afterglow
  46. GRB 050509B and short GRB-SN association? (corrected)
  47. GRB 050509B and short GRB-SN association?
  48. GRB 050509B: Subaru Optical Observations
  49. GRB050502b: Early Observation
  50. GRB050509b, Bok telescope B-band imaging
  51. Refined Chandra analysis of GRB 050509b
  52. GRB050509b, SDSS pre-burst observations
  53. GRB 050509b: Keck/Chandra Cross-Correlation
  54. GRB 050509b: Keck/Chandra Cross-Correlation
  55. Chandra observation of GRB 050509b
  56. GRB 050509b: RAPTOR deep, early limits.
  57. GRB050509B: Optical/Infared observations
  58. GRB 050509b: Swift/UVOT follow-up measurements
  59. GRB 050509b Milagro GeV/TeV Observations
  60. GRB050509B: Optical observations at the Very Large Telescope
  61. GRB 050509b: No Optical Variability in XRT Error Circle
  62. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  63. GRB 050509a: Swift-BAT refined analysis
  64. GRB 050509c: ROTSE-III Optical Limits
  65. GRB 050509B: WSRT Radio Observations
  66. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  67. GRB 050505, early TAROT observation
  68. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  69. GRB 050509b: Further Analysis of Keck LRIS Images
  70. GRB050509c: REM NIR and Optical observations
  71. GRB 050509b: Physical Properties of the Candidate Host galaxy
  72. GRB 050505: SARA Observations
  73. Swift UVOT Follow-up Observations of GRB 050509B
  74. GRB 050509B, Optical Observations
  75. GRB 050509B: Swift/XRT refined analysis
  76. GRB050509a: Swift UVOT observations
  77. GRB 050509b: Optical observations
  78. GRB 050509b: Precision Astrometry
  79. GRB 050509b: Possible Optical Counterpart
  80. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  81. GRB 050509A: Optical observations
  82. GRB 050509b: Optical Counterpart Candidate
  83. GRB050509b: Radio Observations
  84. GRB 050509b: PAIRITEL and WIYN Observations
  85. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  86. GRB 050509b: optical observations
  87. GRB 050509b: Swift XRT Position
  88. GRB 050509B: ROTSE-III Optical Limits
  89. Swift Detection of GRB050509b: A short duration burst
  90. GRB 050509a: Swift XRT Position
  91. Swift Detection of the Burst GRB050509
  92. Swift-BAT detection of GRB 050507
  93. GRB 050505: Keck I-band Magnitude
  94. GRB 050505: early time observations
  95. GRB 050505 - Faulkes Telescope North observations
  96. GRB 050502a: Swift XRT Upper Limit
  97. GRB 050505, simultaneous optical observation
  98. GRB050505: Infrared observations
  99. GRB 050505: Further Swift UVOT observations.
  100. GRB050505: AAVSO observations

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