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 090628: Swift XRT position
  2. GRB 090628: Swift detection of a burst
  3. Fermi LAT observations of GRB 090626
  4. GRB 090625B: Fermi GBM observation
  5. GRB 090423: Spitzer observations of the z~8.3 burst
  6. GRB 090625B: Swift/UVOT Upper Limits
  7. GRB 090625B: Swift-XRT refined analysis
  8. GRB 090626: Fermi GBM detection
  9. GRB 090625B: GROND upper limits
  10. GRB 090623: Suzaku WAM observation of the prompt emission
  11. GRB090618: HCT optical observations
  12. GRB 090618: SARA Second Epoch Observations
  13. GRB 090625B: Faulkes Telescope South observations
  14. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  15. GRB 090625B: a long GRB localized by INTEGRAL
  16. GRB 090625: Fermi GBM detection
  17. GRB 090618: Correction to GCN 9568
  18. GRB 090617: Suzaku WAM observation of the prompt emission
  19. GRB 090618: Suzaku WAM observation of the prompt emission
  20. GRB 090621A: Enhanced Swift-XRT position
  21. GRB 090623: Fermi GBM detection
  22. GRB 090621B: GRT Optical Observation
  23. GRB 090621A: GRT Optical Observation
  24. PAIRITEL observations of GRB 090618
  25. GRB 090621B: Fermi GBM detection
  26. GRB 090621B: I-band observations from 1.23m CAHA
  27. GRB 090621D: Fermi GBM detection
  28. GRB 090621B: Gemini spectrum of afterglow candidate
  29. GRB 090621C: Fermi GBM detection
  30. GRB 090621B: P60 Observations
  31. GRB 090621: Fermi GBM observation
  32. GRB 090621B: VLA observations
  33. GRB 090620: Fermi GBM detecion
  34. Konus-Wind and Konus-RF observations of GRB 090618
  35. GRB 090621B: Swift/UVOT Upper Limits
  36. GRB 090621B: Swift-BAT refined analysis
  37. GRB 090621B: Swift-XRT refined analysis
  38. GRB 090621B: RTT150 optical observations
  39. GRB 090618: RTT150 optical observations
  40. GRB 090621B: Optical Observations
  41. GRB 090621A: Swift-BAT refined analysis
  42. GRB 090621B: Swift detection of a short hard burst
  43. GRB 090621: Swift/UVOT Upper Limits
  44. GRB 090621: Swift-XRT Team refined analysis
  45. GRB090618: Spectrum and photometry from 6.0m BTA
  46. GRB 090618: BOAO V-band Observation
  47. GRB 090621: Swift detection of a burst
  48. GRB 090618: ZTSh optical observations
  49. GRB 090618 : WSRT radio detection
  50. GRB090618, underlying supernova search
  51. GRB090618: OAA-OAUV Optical observations
  52. GRB 090618: Fermi GBM observation
  53. GRB 090618, Swift-BAT refined spectral analysis
  54. VLA radio detection of GRB 090618
  55. GRB 090618 15GHz radio detection
  56. GRB090618 - Continued optical monitoring and light curve break
  57. GRB 090618: Swift-BAT refined analysis
  58. GRB 090618: SARA observations
  59. GRB090618: Swift-XRT team refined analysis
  60. GRB090618: Swift/UVOT bright afterglow detection
  61. GRB 090618: SDSS host detection
  62. Swift XRT observations of GRB 090531A
  63. GRB 090618: AGILE observations
  64. GRB 090617: Fermi GBM detection
  65. GRB 090618: LOAO R-band Observation
  66. GRB 090618: Enhanced Swift-XRT position
  67. GRB 090618 Faulkes Telescope North observations
  68. Optical observations of GRB 090618
  69. GRB 090618: Lick/KAST Spectroscopy
  70. GRB 090618: OA behavior from KAIT
  71. GRB 090618: planned XMM-Newton observation
  72. GRB 090618: ROTSE-III Detection of Optical Counterpart
  73. GRB 090618: KAIT optical afterglow
  74. GRB090618: P60 Optical Afterglow
  75. GRB 090618: Swift detection of a bright burst with optical afterglow
  76. GRB 090616: Fermi GBM detection
  77. GRB 090612: Fermi GBM detection
  78. GRB 090610C: Fermi GBM detection
  79. GRB 090610B: Fermi GBM detection
  80. GRB 090610: Fermi GBM detection
  81. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  82. GRB 090602: Suzaku WAM observation of the prompt emission
  83. GRB 090424: WSRT Radio Observations
  84. GRB 090423: WSRT Radio Observations
  85. RXTE Discovery of Pulsations from SGR 0418+5729
  86. GRB 090531B: Fermi GBM detection
  87. Konus-RF observation of SGR burst 090605A
  88. Discovery of a new soft gamma repeater source, SGR 0418+5729
  89. GRB 090608: Fermi GBM detection
  90. GRB 090606: Fermi GBM detection
  91. GRB 090607: XRT Team Refined Analysis
  92. GRB 090607: Swift/UVOT Upper Limits
  93. GRB 090607: Swift-BAT refined analysis of the SHB
  94. GRB 090607: GRAS001 optical observations
  95. GRB 090607: Faulkes Telescope North observations
  96. GRB 090607: Swift detection of a burst
  97. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  98. GRB 090530B: Suzaku WAM observation of the prompt emission
  99. GRB 090530: Further NOT optical observations
  100. GRB 090530: RTT150 Optical Observation

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