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"
  1. GRB050709: Radio Observations
  2. GRB 050709: Swift UVOT and XRT observations
  3. GRB 050712: Swift-BAT Refined Analysis
  4. GRB050712: UVOT candidate optical counterpart
  5. GRB 050712: Swift XRT afterglow position
  6. GRB 050712: Swift detection of a weak burst
  7. GRB 050709: LCO40 Observations
  8. GRB050709, optical observations
  9. GRB050709: A Possible Short-Hard GRB Localized by HETE
  10. PROMPT Rc Observations of GRB 050709
  11. GRB 050525a: PROMPT VRcIc Detections
  12. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  13. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  14. GRB 050626 optical observations
  15. GRB 050626: Swift XRT observations
  16. GRB 050701
  17. GRB 050701, optical observations
  18. GRB 050408: ARC 3.5-meter NIR Observations
  19. GRB 050701: Refined XRT analysis
  20. Swift UVOT observations of GRB 050701
  21. GRB050701: Swift-BAT Refined analysis
  22. GRB 050701: Swift XRT afterglow position
  23. Swift trigger 143708 is really GRB 050701
  24. GRB 050607, radio observations
  25. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  26. GRB 050626 - Correction to GCN 3552
  27. GRB 050626 - a long GRB detected with INTEGRAL
  28. GRB 050525A: Swift Late-Time Decay Rate
  29. GRB050525a: HST Observations
  30. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  31. H3804: A Possible New XRB Detected by HETE
  32. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  33. XRF 050509c: Optical monitoring
  34. Konus-Wind observation of an intermediate burst from SGR 1806-20
  35. IBAS Alert #2512 is NOT a GRB
  36. XRF050509c: Radio Detection
  37. GRB 050416(a): Host Galaxy Redshift Determination
  38. GRB 050607: MDM Observation
  39. GRB 050607 optical decay
  40. GRB 050607: RTT150 optical observations
  41. GRB050607: refined analysis of prompt REM observations
  42. Swift/UVOT observations of GRB050607
  43. GRB 050607 : Lulin R-band observation
  44. GRB 050607: PROMPT VRcIc Observations
  45. GRB 050607: RAPTOR-S Early Optical Limits
  46. GRB050607: KAIT optical limits
  47. GRB 050525a, Mid-Infrared Observations
  48. GRB 050607: Optical decay and spectral slope
  49. GRB 050607: MDM Observations
  50. GRB050607,optical observation
  51. GRB 050607 - XRT refined data analysis
  52. Optical Afterglow of GRB 050607
  53. GRB050607 optical limit by "Pi of the Sky"
  54. GRB050607: Swift Detection of a long GRB
  55. GRB050607: P60 Observations
  56. GRB050607: prompt REM observations
  57. GRB 050603: prediction of t_break
  58. Limits on a SN in the field of GRB 050509b
  59. GRB 050603: Redshift
  60. GRB 050603 - XRT data analysis of the first day
  61. Konus-Wind observation of GRB 050603
  62. GRB 050603: Analysis of UVOT data
  63. GRB050603: Fading Afterglow observed by Swift UVOT
  64. GRB050603, submillimetre observations
  65. GRB 050603: Swift XRT Position
  66. GRB050603: Radio Detection
  67. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  68. GRB 050603: Afterglow Identification from LCO
  69. GRB 050603: INTEGRAL shows it is not a short GRB
  70. Swift/BAT Detection of GRB050603
  71. GRB 050408: jet break in the XRT light curve
  72. GRB 050525a, infrared observations
  73. GRB 050525a, SMARTS optical/IR afterglow observations
  74. GRB050528, XRT observations
  75. Correction to GCN Circ 3502 on GRB 050528
  76. GRB050528: updated Liverpool Telescope limits
  77. Swift-BAT GRB 050528: a soft burst
  78. Update on Swift-BAT GRB 050528 (Trigger 130679)
  79. GRB050528: BOOTES optical candidate (retraction)
  80. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  81. GRB050528: BOOTES optical candidate
  82. Possible GRB050528: no candidate from Liverpool Telescope
  83. Swift-BAT detection of possible GRB 050528
  84. GRB050525a: Radio Observations
  85. GRB 050509b: refined XRT/Chandra afterglow position analysis
  86. GRB 050525: RTT150, Optical observations
  87. GRB050525a: optical upper limits
  88. GRB 050525a: SARA Observations
  89. GRB 050525B: Swift-BAT observations
  90. GRB 050525: MITSuME Optical Observation in VRI
  91. GRB 050525a: MDM Observations
  92. GRB050525A,optical observation
  93. GRB 050525 : Lulin optical afterglow observations
  94. GRB050525: Super-LOTIS observations
  95. GRB 050525, spectral lag pseudo-redshift
  96. GRB 050525a: Gemini/GMOS Spectra
  97. GRB050306: optical afterglow not confirmed
  98. GRB 050525: BART optical observation
  99. GRB 050525A: BOOTES simultaneous optical observations
  100. GRB 050525A: Swift-BAT refined analysis

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