Skip to main content
New! BOOM Notices and Schema v7.0.0. 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 100906A: optical observations at Mt.Terskol
  2. GRB 100901A: optical observation in Maidanak, break confirmation
  3. GRB 100909A: Faulkes Telescope North afterglow candidate
  4. GRB 100909A: ROTSE-III Optical Limits
  5. GRB 100909A: Planned XMM-Newton observation
  6. GRB 100902A : Confirmation of afterglow and re-brightening with CFHT r’-band imaging
  7. GRB 100909A: Swift target of opportunity observation
  8. GRB 100909A: a long GRB detected by INTEGRAL
  9. GRB100906A: detection at 15GHz
  10. GRB100901A: IAO optical upper limits at 4 days after the burst
  11. EVLA detection of radio afterglow of GRB100901A
  12. GRB 100901A: Confirmation of WSRT Radio Detection
  13. GRB 100901A: CrAO optical observations
  14. GRB 100906A: RTT150 optical observations
  15. GRB 100906A: GRAS-007 optical observations
  16. GRB100906A: R band observations
  17. Konus-Wind observation of GRB 100906A
  18. GRB100906A: non-detection at 15GHz
  19. GRB100906A: Optical observations at IAO
  20. GRB 100906A: Fermi GBM observation
  21. GRB 100906A: TLS Monitoring
  22. GRB 100901A: TLS Detection at 5.5 days
  23. GRB 100906A: Observations at the Virtual Telescope
  24. GRB 100906A: Swift-XRT refined analysis
  25. GRB 100906A: Enhanced Swift-XRT position
  26. GRB 100906A: Swift/UVOT Observations
  27. GRB100906A: Errata of MITSuME Okayama about observation time
  28. GRB100906A: MITSuME Okayama Optical Observation
  29. GRB 100906A: Ondrejov 65cm observations
  30. GRB 100906A: TLS Multicolor Observations
  31. GRB 100905A: Swift/UVOT Upper Limits
  32. GRB 100901A: TLS observations, SDSS calibration, decay slope
  33. GRB 100906A: MASTER preliminary prompt+afterglow lc
  34. GRB 100901A: ISON-NM optical observations
  35. GRB 100906A: Swift-BAT refined analysis
  36. GRB 100906A: UKIRT zYJHK Observation
  37. GRB 100906A: MASTER preliminary polarization prompt light curve
  38. GRB 100906A: Gemini-N/GMOS redshift
  39. GRB 100906A : Faulkes Telescope North optical observations
  40. GRB 100906A: MASTER early OT observations
  41. GRB 100906A: Swift detection of a burst with an optical afterglow
  42. GRB 100829A: MASTER optical observations
  43. GRB100905A: Optical upper limits at IAO
  44. GRB100905A: MITSuME Okayama optical upper limits
  45. GRB 100905A: Swift-XRT refined analysis.
  46. GRB 100905A: UKIRT zJHK Observation
  47. GRB 100901A: Possible WSRT Radio Detection
  48. GRB100905A: 1.5m OSN upper limit
  49. GRB 100905A: Enhanced Swift-XRT position
  50. GRB 100905A: Swift-BAT refined analysis
  51. GRB100904A: BOOTES-3 Upper Limit
  52. GRB 100905A: MASTER Prompt Optical Observations
  53. GRB 100905A: Faulkes Telescope North observations
  54. GRB 100905A: Swift detection of a burst
  55. Optical observations of GRB 100901A
  56. GRB10901A: Murikabushi telescope observation at 3 days after the burst
  57. GRB 100901A: Submm observations from SMA
  58. GRB 100902A: UKIRT JK Observation
  59. GRB 100902A: GROND observations; afterglow candidate
  60. GRB 100901A: UKIRT zYJHK Observation
  61. GRB 100904A: Swift-BAT refined analysis
  62. GRB100902A: Optical upper limits at IAO
  63. GRB10901A: Optical observations at IAO
  64. Konus-Wind observation of GRB 100829A
  65. GRB 100904A: Swift detection of a burst
  66. GRB 100902A: Swift-BAT refined analysis
  67. GRB 100901A: optical observation at Mt.Terskol
  68. GRB 100901A: multicolor photometry at Mt.Terskol
  69. IPN Triangulation of the very bright GRB 100829A
  70. GRB 100901A: Lightbuckets Optical Observations
  71. GRB 100901A: HCT optical observations
  72. GRB 100902A: 1.5m OSN I-band Upper Limits
  73. Tentative redshift of GRB100902A from Swift-XRT data
  74. GRB 100902A: Swift XRT refined analysis
  75. GRB 100902A: Swift/UVOT Upper Limits
  76. GRB 100902A: optical observation at Mt.Terskol
  77. GRB 100901A: optical observation at Mt.Terskol
  78. GRB 100901A: Kanata Telescope observation of the optical afterglow
  79. GRB100901A: MITSuME Okayama Optical Observation at 1 day after the burst
  80. GRB 100902A: Enhanced Swift-XRT position
  81. GRB 100901A: TLS Observations: Break?
  82. GRB100901A: Errata of MITSuME Okayama about reference catalog
  83. GRB 100902A: MASTER Prompt Optical Observations
  84. GRB 100901A: ISON-NM optical observations
  85. GRB 100902A: Faulkes Telescope South observations
  86. GRB 100902A: MASTER Optical Early Limit
  87. GRB 100902A: Swift detection of a burst
  88. GRB 100901A: 1.5m OSN BVRI-band observations.
  89. GRB 100901A: ROTSE-III Detection
  90. GRB 100901A: MASTER optical flare at 420s discovery
  91. GRB 100901A: Vega telescope optical afterglow observation
  92. Swift/UVOT Observations of GRB100901A
  93. GRB 100901A : HCT optical observations
  94. GRB 100901A: SARA-N observations
  95. GRB 100901A: THO optical observations
  96. GRB100901A: MITSuME Okayama Optical Observation
  97. GRB 100901A: Swift-XRT Team refined analysis
  98. GRB 100901A - NOT optical observation
  99. GRB 100901A: Swift-BAT refined analysis
  100. GRB 100901A: optical observation at Mt.Terskol

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