Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
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. GRB 050416: Swift/UVOT refined analysis
  2. Swift-BAT detection of GRB 050416b
  3. IBAS GRB Alert # 2463: not a GRB
  4. GRB050412: Radio Observations
  5. GRB 050416: Swift/UVOT detection of afterglow emission
  6. GRB050416: Refined Swift-XRT analysis
  7. GRB050416: Maidanak optical observations
  8. GRB 050416: Swift-BAT refined analysis
  9. GRB 050416: ART observations
  10. GRB 050416,optical observation
  11. GRB 050416: KAIT observations
  12. GRB050416: P200 NIR Observations
  13. GRB 050416: Swift XRT Position
  14. GRB 050416: Radio observations
  15. Confirmation of OT for GRB050416
  16. GRB050416: P60 Afterglow Candidate
  17. Swift BAT/XRT Detection of GRB 050416
  18. GRB 050412: Subaru observations
  19. GRB 050408: RTT150 optical observations
  20. GRB050408: optical observation
  21. GRB 050412: PROMPT VRcIc Observations
  22. GRB 050408: Kuiper 1.5m observations
  23. GRB 050412: optical limit
  24. GRB 050412: optical observations
  25. GRB 050408: refined XRT analysis, no jet break seen yet
  26. GRB 050412: early Swift XRT analysis results
  27. GRB 050412 : XingLong optical observation
  28. GRB 050412: Swift-BAT refined analysis
  29. GRB 050412: ANU 2.3m observations
  30. GRB 050412: Early Optical/Ultraviolet Observations with
  31. GRB 050412: retraction of UVOT transient report
  32. GRB 050412: UVOT transient not in XRT error circle
  33. GRB 050408: SDSS Field Calibration
  34. GRB 050412: Optical limit
  35. GRB 050412: LCO Optical Observations
  36. GRB 050412: Optical observations
  37. GRB050412: P60 Observations
  38. GRB 050412: Swift XRT Position
  39. GRB050412: optical limit before and during GRB
  40. GRB 050412: LCO optical observations
  41. GRB050412: ROTSE-III Optical Limits
  42. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  43. GRB 050412: IR and Optical observations
  44. GRB 050412: IR Observations
  45. GRB050408: Radio Observations
  46. GRB 050401: Optical limit
  47. GRB 050408: Optical limit
  48. GRB050410: P60 Observations
  49. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  50. GRB 050410, optical observations
  51. GRB 050408: PROMPT VRcIc Observations
  52. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  53. GRB 050410 R band Optical Observations
  54. GRB050410 : Null detection report
  55. GRB 050410, optical observations
  56. GRB050410: Radio Observations
  57. GRB 050408: Swift XRT measurement of possible jet break
  58. GRB050410: MASTER optical observations
  59. GRB 050410: Early observations with Swift-UVOT
  60. Swift-BAT detection of GRB 050410
  61. GRB 050410: Swift XRT Position
  62. GRB 050408: Retraction of Proposed Host Galaxy
  63. GRB 050408: Inconsistency of host galaxy identification
  64. GRB 050408: Subaru Observations
  65. GRB 050408: WIDGET simultaneous optical observations
  66. GRB 050408: SOAR UBVRc Observations
  67. GRB 050408: Properties of the Host Galaxy
  68. GRB 050408: Mercator Optical Observations
  69. GRB050408: Radio Observations
  70. GRB 050408: Swift XRT analysis
  71. GRB 050408, SMARTS optical/IR afterglow observations
  72. GRB 050408: Optical limit at 20 min after the burst
  73. GRB 050408, optical observations
  74. GRB050408: REM NIR and Optical observation
  75. GRB 050408: Moderate-resolution Gemini Spectroscopy
  76. GRB 050408,optical observation
  77. GRB 050408 Optical Observations
  78. GRB 050408: Emission and absorption redshift
  79. GRB 050408: Mercator Optical Observations
  80. GRB 050408: Magellan astrometry and photometry
  81. GRB 050408: First Optical observations with TFOSC at the RTT150
  82. GRB 050408: steepening of the optical decay
  83. GRB 050408: Optical afterglow confirmed
  84. GRB 050408: opitcal observation
  85. GRB 050408, optical observations
  86. GRB 050408 optical candidate
  87. GRB 050408: Swift XRT Position
  88. GRB 050408: ROTSE-III Optical Limits
  89. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  90. GRB050408: MASTER optical observations
  91. GRB050401: Radio Detection
  92. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  93. GRB 050406: Magellan optical observations
  94. GRB 050406: early Swift XRT analysis results
  95. GRB 050406 BAT refined analysis
  96. GRB 050406: Early observations with Swift-UVOT
  97. GRB 050406: Swift XRT Position
  98. Swift-BAT detection of GRB 050406
  99. Konus-Wind observation of GRB 050401
  100. GRB050401: Radio observation at 610 MHz with GMRT

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