Skip to main content
Circulars over Kafka event name backfill. 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. GRB060403: Swift XRT refined position
  2. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  3. GRB 060403: Swift detection of a burst
  4. HETE trigger H4044: RTT150 optical observations
  5. GRB060331: Swift/UVOT upper limits
  6. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  7. Swift XRT observations of the HETE transient H4043
  8. HETE Trigger 4043: ROTSE-III Optical Limits
  9. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  10. H4043, an unusual high-energy transient observed by HETE
  11. GRB 060322: LNA optical limit
  12. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  13. INTEGRAL and XMM ToO observations of SGR1900+14
  14. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  15. SGR 1900+14: Swift-BAT detection of a bright outburst
  16. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  17. GRB 060323 : WIDGET simultaneous optical observations
  18. GRB 060323: Early optical observation at Xinglong
  19. GRB060218, optical observations
  20. GRB 060322: Confirmation of Swift XRT afterglow
  21. GRB 060211A: optical observation
  22. GRB060323: optical limit
  23. GRB060211B: optical observation
  24. SGR 1900+14: CORRECTION to GCN 4923
  25. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  26. SGR 1900+14: Swift detection of renewed activity
  27. GRB060323: NOT optical observations
  28. GRB 060322: IAC80 optical observations
  29. GRB 060322: Swift XRT afterglow candidate
  30. GRB060323: P60 Observations
  31. GRB 060323: Swift/UVOT Observations
  32. GRB 060323: optical afterglow confirmed
  33. GRB060323: NOT observations
  34. GRB 060323: Optical Observations
  35. GRB 060323: Tautenburg OT candidate retraction
  36. GRB 060323: Refined analysis of the Swift-BAT burst
  37. GRB 060323: optical observations at TNG
  38. GRB 060323: Swift XRT refined analysis
  39. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  40. GRB 060323: Swift/XRT position
  41. GRB 060322: Refined analysis of the Swift-BAT burst
  42. GRB060323, optical observation
  43. GRB060323 - SDSS Pre-Burst Observations
  44. GRB 060323: Swift detection of a burst with a possible optical afterglow
  45. GRB 060322: Swift-BAT detection of a 200-sec burst
  46. GRB060219: optical observation
  47. GRB060206: optical observation
  48. GRB060218/SN2006aj: optical observations
  49. GRB 060218/SN 2006aj, LNA optical observation
  50. GRB060218: Refined photometric calibration of comparison stars
  51. GRB 060319: WHT K-band candidate afterglow
  52. GRB 060319: IAC-80 optical observations
  53. GRB060319: Swift XRT refined analysis
  54. GRB060319: Swift/UVOT upper limits
  55. GRB 060319: Re-analysis of TNG data
  56. GRB060319: MASTER limit
  57. GRB 060319: Swift-BAT refined analysis
  58. GRB 060319 optical observations at TNG
  59. GRB060319 : Liverpool Telescope optical limit
  60. GRB060319: MASTER optical observation
  61. GRB060319 - SDSS Pre-burst Observations
  62. GRB060319: Swift/XRT position
  63. GRB 060319: Swift detection of a burst
  64. GRB060313: Radio Observations
  65. GRB 060313: early afterglow NIR upper limits with REM
  66. IBAS Alert n. 3221: not a GRB
  67. Konus-Wind observation of GRB 060313
  68. GRB060313: SSO 40inch Observations
  69. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  70. GRB 060313: PROMPT Observations
  71. GRB 060313: Swift/UVOT Observations
  72. GRB060313:Gemini South Observations
  73. GRB 060313: Swift-XRT team refined analysis
  74. GRB060313: optical observations of the afterglow candidate
  75. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  76. GRB 060313, SMARTS optical counterpart?
  77. GRB 060313: Possible optical counterpart
  78. GRB 060313: Swift XRT position
  79. GRB 060313, SMARTS optical/IR observations
  80. GRB060313: optical and near infrared observations with REM
  81. GRB 060313: Swift-BAT detection of a bright short hard burst
  82. GRB060218: SARA Observations of SN2006aj
  83. GRB060312: Swift UVOT observation
  84. GRB 060312: Refined analysis of the Swift-BAT burst
  85. GRB 060218/SN 2006aj, high resolution spectra
  86. GRB 060312: Swift XRT team refined analysis
  87. GRB060306: APO Ks-band Imaging Observations
  88. GRB 060312: ROTSE-III Optical Limits
  89. GRB 060312: Swift detection of a burst
  90. IBAS Alert n. 3218 : not a real GRB
  91. GRB 060306: SOAR Ks Observations
  92. Bright short hard GRB 060303: IPN localization and Konus spectrum
  93. GRB060219: Liverpool Telescope observations
  94. GRB 060306: MAGNUM observations
  95. GRB060218: analysis of the XMM-Newton observation
  96. Swift/UVOT observations of GRB060306
  97. GRB 060306: Swift-BAT refined analysis
  98. GRB 060306: Swift-XRT team refined analysis
  99. GRB 060306: PROMPT Observations
  100. GRB 060306: Swift detection of a bright burst

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