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 071021: Subaru NIR observation
  2. GRB071021: MITSuME Okayama Optical Upper Limits
  3. GRB 071021: Magellan i-band observation
  4. GRB 071021: Magellan R-band observation
  5. GRB 071021: Z-band detection
  6. GRB 071021: correction to GCNC 6968
  7. GRB 071020: Fading slowly?
  8. GRB 071010B: Fading quickly
  9. GRB 071021: optical and NIR observations
  10. GRB 071021: possible high-z burst
  11. GRB 071021, Swift-BAT refined analysis
  12. GRB071018: 2nd epoch obsevations of Xinglong TNT
  13. GRB 071021: retraction of Faulkes Telescope South candidate
  14. GRB 071021: Swift-XRT Team refined analysis
  15. GRB 071021: Xinglong TNT optical Upper Limit
  16. GRB 071021 : Lulin R-band limit
  17. Konus-Wind observation of GRB 071020
  18. GRB 071021: Faulkes Telescope South optical candidate
  19. GRB 071021: Swift detection of a burst
  20. GRB 071010B: Independent Confirmation of Break
  21. GRB071020A: Xinglong TNT Optical afterglow observations
  22. GRB 071020: Swift-XRT refined analysis
  23. GRB 071020, Swift-BAT refined analysis
  24. GRB 071020A: IR Imaging with PAIRITEL
  25. GRB 071020: VLT spectroscopy
  26. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  27. GRB071020 - SDSS Pre-burst Observations
  28. GRB 071020: Swift detection of a bright burst
  29. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  30. GRB 071018: Mercator Telescope optical observations
  31. Swift autonomous slewing re-enabled
  32. GRB071010b: optical observations
  33. GRB 071018: SARA observations
  34. GRB 071018: Swift-XRT observation
  35. GRB 071017 - Swift XRT observations
  36. VLA radio observation of GRB 071018
  37. GRB071018: Correction to the GCN 6936
  38. GRB071018: Correction to the GCN 6936
  39. GRB071018: Correction to the GCN 6936
  40. GRB071018: Correction to the title of the GCN 6936
  41. GRB 071018: Possible OT from Xinglong TNT observation
  42. GRB 071010B: Light Curve Break Confirmed
  43. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  44. GRB 071018, Swift-BAT refined analysis
  45. GRB 071018?: Swift detection of a possible burst
  46. GRB 071010B: Suzaku WAM observation of the prompt emission
  47. GRB 071013: 3rd TLS Epoch - constraints on variability
  48. GRB 071013: TNT optical data refined analysis
  49. GRB 071010B: Keck/DEIMOS emission-line redshift
  50. GRB 071017: a SHORT GRB detected by INTEGRAL
  51. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  52. GRB071013: optical observations
  53. GRB 071010B: Optical observations of EST
  54. GRB 071010B: TLS 3rd Epoch - finally a break??
  55. GRB 071011: MITSuME Optical Observations
  56. GRB 070920A: deep optical observations at the NOT
  57. GRB 071010B: Photometry after 1.6 days
  58. GRB 071010B: Keck/LRIS Photometry
  59. GRB 071010B: TLS 2nd Epoch, refined analysis
  60. GRB 071013: TLS Upper Limit
  61. Correction to GCN circular no. # 6915 for GRB 071010B
  62. VLA detection of radio afterglow of GRB 071010B
  63. VLA non-detection of GRB 071011
  64. GRB 071013: Optical observations
  65. GRB 071013: optical observations at NOT
  66. GRB 071013, Swift-BAT refined analysis
  67. GRB071013: optical limit
  68. GRB071010B, BVRcIc field calibration
  69. GRB 20071013: Xinglong TNT optical Upper Limit
  70. GRB 071013: Swift detection of a burst
  71. GRB 071010C Swift-BAT detection of a burst
  72. GRB 071011: Optical Limit after 13.95hrs
  73. GRB 071011: Xinglong TNT Optical afterglow observations
  74. GRB 071010B correction to GCN 6892 optical observations
  75. GRB 071011: Swift-XRT refined analysis
  76. VLA non-detection of GRB 071010A
  77. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  78. GRB 071011, Optical afterglow
  79. GRB 071011: Confirmation of P60 optical afterglow
  80. GRB 071010B: Optical Detection
  81. GRB 071011: Kanazawa Optical limits
  82. GRB 071011: P60 Optical Afterglow Candidate
  83. GRB 071011: MARGE Optical Limits
  84. GRB 071010B: Super-LOTIS upper limit
  85. GRB 071010B optical photometry
  86. GRB 071011: XRT afterglow detection
  87. GRB 071010B: Keck/LRIS Spectroscopy
  88. GRB 071011, Swift-BAT refined analysis
  89. GRB 071010B: Gemini Spectroscopic Observations
  90. GRB 071011: Early Super-LOTIS Observations
  91. GRB 071011: NAYUTA Optical Observation
  92. GRB 071010A: Continued Keck Imaging
  93. GRB 071010B: Bright OT confirmed with TLS
  94. GRB 071011: Optical afterglow candidate
  95. GRB 071011: Swift detection of a burst
  96. Optical Observation: GRB 071010
  97. Optical observations: GRB 071010A
  98. Konus-Wind observation of GRB 071010B
  99. GRB071010B: Swift/XRT detection
  100. GRB 071010B, Swift-BAT refined analysis

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