Skip to main content
Retirement of GCN Classic VOEvent Brokers. 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 070810B: Keck spectroscopy of possible host galaxies
  2. GRB070810B: Swift/UVOT Upper Limits
  3. GRB 070810B: XRT refined analysis
  4. GRB 070810B, Swift-BAT refined analysis
  5. GRB 070810: MASTER optical observation
  6. GRB 070809: Swift/UVOT Corrected Photometry
  7. Swift Alert 070810.8: MASTER optical observation
  8. Swift Trigger 287421: False trigger due to star tracker loss
  9. GRB 070810A: Swift-BAT refined analysis
  10. GRB 070810B: Xinglong TNT optical Upper Limit
  11. GRB070810B: Optical observations with KANATA
  12. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  13. GRB 070809: Swift/UVOT Upper Limits
  14. GRB 070810B: Swift detection of a short burst
  15. VLA upper limit on the short hard burst GRB 070729
  16. GRB 070810: Keck redshift and photometry
  17. No radio detection in superAGILE burst 070724B
  18. GRB 070809: Keck Imaging
  19. GRB 070810: Swift-XRT Team Refined Analysis
  20. GRB 070809: Swift-XRT refined analysis
  21. GRB 070810: enhanced Swift-XRT position
  22. GRB 070810: Swift/UVOT Optical Counterpart
  23. GRB 070810: ROTSE-III Detection of Optical Counterpart
  24. GRB 070810: Swift detection of a burst
  25. GRB 070809, Swift-BAT refined analysis
  26. GRB 070809: Optical Pre-imaging from Palomar
  27. GRB 070808: Swift/UVOT upper limits
  28. GRB 070809: ROTSE-III Optical Limits
  29. GRB 070809: Swift detection of a short burst
  30. GRB 070808 : Faulkes Telescope South Observations
  31. GCN Swift XRT update position notices and enhanced position circulars
  32. GRB 070808: Swift XRT refined analysis
  33. GRB 070808, Swift-BAT refined analysis
  34. GRB 070808: OPTIMA-Burst optical upper limit
  35. GRB 070808: Xinglong TNT optical Upper Limit
  36. GRB070808: Optical observations with KANATA
  37. GRB070808 - SDSS Pre-Burst Observations
  38. GRB 070808: ROTSE-III Optical Limits
  39. GRB 070808: Swift detection of a burst
  40. GRB061121A: PROMPT Observations
  41. GRB070805 XRT and UVOT afterglow candidate
  42. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  43. GRB070612A: Radio upper limit from GMRT
  44. GRB 070721B: correct afterglow position
  45. Swift/UVOT observations of GRB070805
  46. GRB 070805, Swift-BAT refined analysis
  47. GRB 070805: Swift XRT initial analysis.
  48. GRB 070805: Swift/UVOT initial analysis
  49. GRB 070805: Swift detection of a burst
  50. UVOT observations of SAXJ1810.8-2609
  51. Swift detection of a outburst from SAX J1810.8-2609
  52. VLA non-detection of GRB 070721B
  53. GRB 070802: REM optical observations
  54. GRB 070724B: Swift-XRT afterglow confirmation
  55. GRB 070802: Swift-XRT refined analysis
  56. GRB070802: Swift/UVOT upper limits
  57. GRB 070802: Confirmation of the optical afterglow
  58. GRB 070802, Swift-BAT refined analysis
  59. GRB 070802: VLT redshift
  60. GRB 070802: refined Swift XRT position
  61. GRB 070802: V-band detection of the candidate afterglow
  62. GRB 070802: LCO I-band candidate
  63. GRB 070802: GROND J band candidate
  64. GRB 070802: LCO optical observations
  65. GRB 070802: Swift detection of a burst
  66. GRB 070731, Swift-BAT refined analysis
  67. Konus-A observation of GRB 070729
  68. Swift/UVOT detection of GRB070714B
  69. AGILE-ACS position for the SGR 1806-20 July 27 burst
  70. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  71. GRB 070729: LCO optical imaging
  72. VLA upper limit on short hard burst GRB 070714B
  73. Intense burst from SGR 1806-20 detected on July 27
  74. GRB070729: Swift/UVOT upper limits
  75. GRB 070729: Swift-XRT refined analysis
  76. GRB 070729, Swift-BAT refined analysis
  77. GRB 070729: Magellan NIR Observations
  78. GRB 070724B: P60 Observations
  79. GRB 070729: Swift detection of a short hard burst
  80. GRB 070724B: Swift/UVOT Upper limits
  81. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  82. GRB 070724B: Swift-XRT afterglow likely candidate
  83. GRB 070721A: optical observations
  84. GRB 070724A: further VLT observations
  85. GRB 070724B: Suzaku WAM observation of the prompt emission
  86. Konus-Wind observation of GRB 070724B
  87. GRB 070724B: Analysis of AGILE gamma-ray data
  88. GRB 070724B: Swift-XRT afterglow candidates
  89. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  90. Four radio sources in Swift-XRT error box of GRB 070724
  91. GRB 070724: optical observations
  92. GRB070724: Host galaxy redshift
  93. GRB 070724: P60 and Gemini Observations
  94. GRB 060814 - Keck host detection and redshift
  95. GRB 070724: IR observations
  96. GRB 070724: Closer association with DSS source
  97. Swift/UVOT refined analysis of GRB070724
  98. GRB 070724: Swift-XRT Team refined analysis
  99. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  100. Short-Hard GRB070714B: PROMPT 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