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. GRB 160303A: Swift/UVOT Detection
  2. GRB 160303A: RAPTOR Observations During Gamma-Ray Emitting Interval
  3. GRB 160303A: Enhanced Swift-XRT position
  4. GRB 160303A: RATIR Optical and NIR Afterglow Detection
  5. GRB 160303A: MITSuME Akeno optical upper limits
  6. GRB 160303A: LCOGT-FTN optical observations
  7. GRB 160303A: MITSuME Okayama upper limits
  8. GRB 160303A: ISON-NM early optical early limits
  9. GRB 160303A: Swift detection of a burst, possibly short
  10. GRB 160227A: LOAO 1.0m optical detection
  11. GRB 160227A: McDonald 0.8m Detection
  12. GRB 160228A: Swift/UVOT Upper Limits
  13. GRB 160227A: Swift/UVOT Detection
  14. GRB160228A: Further analyses on spectral lag and extended emission
  15. GRB 160228A: Mondy optcial observations
  16. GRB 160228A: RATIR Optical and NIR Observations
  17. GRB 160228A: MASTER-Amur prompt observations
  18. GRB 160228A: Swift-XRT refined Analysis
  19. GRB 160227A: MASTER prompt OT Detection and LC
  20. GRB 160227A: AROMA-N Optical Observation
  21. GRB 160228A: GROND Afterglow Candidate
  22. GRB 160228A: Swift-BAT refined analysis
  23. GRB 160228A: optical observations
  24. GRB 160227B: Fermi GBM detection
  25. GRB 160228A: Enhanced Swift-XRT position
  26. GRB 160227A: NOT redshift
  27. GRB 160228A: Prompt enhanced Swift-XRT position
  28. GRB 160228A: Swift detection of a burst
  29. GRB 160227A, Swift-BAT refined analysis
  30. GRB 160227A: Swift-XRT refined Analysis
  31. GRB 160227A: Enhanced Swift-XRT position
  32. GRB 160227A: MAXI/GSC detection
  33. GRB 160225A: TSHAO optical afterglow detection
  34. GRB 160227A: ISON-Kislovodsk optical observation
  35. GRB 160227A: Mt. Terskol observatory optical observation
  36. GRB 160227A: MASTER OT Detection
  37. GRB 160227A: Swift detection of a burst with an optical counterpart
  38. GRB 160225A: LOAO optical upper limit
  39. GRB 160225B: Fermi GBM detection
  40. IPN Triangulation of GRB 160225B
  41. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 follow up observations
  42. GRB 160225A: Continued RATIR Optical and NIR Observations
  43. GRB 160225.81/FERMI Trigg 478121069: MASTER OT J095503.19-355149.4 detection
  44. GRB 160225A: Swift-BAT refined analysis
  45. Fermi GBM trigger 478156376/16022621 is not a GRB
  46. GRB 160225A: MASTER-Amur observations
  47. GRB 160225A: RATIR Optical and NIR Observations
  48. GRB 160225A: Swift/UVOT Upper Limits
  49. GRB 160225A: Xinglong TNT optical observation
  50. GRB 160223B: CALET Gamma-Ray Burst Monitor detection
  51. GRB 160225A: Swift-XRT refined Analysis
  52. GRB 160225A: NOT optical observations
  53. GRB 160225A: WHT LIRIS observations
  54. GRB 160225A: MITSuME Okayama Optical Observation
  55. GRB 160225A: MITSuME Akeno Optical Observation
  56. GRB 160223A: RATIR Optical and NIR Observations
  57. GRB 160225A: TSHAO optical upper limit
  58. GRB 160225A: Enhanced Swift-XRT position
  59. GRB 160225A: MASTER-Amur early observations
  60. GRB 160225A: Swift detection of a burst
  61. GRB 160223A: Swift-XRT afterglow detection
  62. GRB 160221A: Swift-XRT afterglow detection
  63. GRB 160223A: AbAO optical observations
  64. Swift trigger 675784 is probably not an astrophysical source
  65. Konus-Wind observation of GRB 160219A
  66. GRB 160223B: MASTER-Amur early observations
  67. Fermi GBM trigger 477460274/160218161 is not a GRB
  68. Fermi GBM trigger 477985003/160224234 is not a GRB
  69. GRB 160223A: Swift-BAT refined analysis
  70. GRB 160223B: Khureltogot optical observations
  71. GRB 160223A: Fermi GBM observation
  72. GRB 160223B: Swift-XRT observations
  73. GRB 160223B: LCOGT-FTN optical observations
  74. GRB 160223B: Fermi GBM observation
  75. GRB 160223B: Swift ToO observations
  76. GRB 160223B: A long GRB detected by INTEGRAL
  77. GRB 160223A: GROND optical/NIR afterglow
  78. GRB 160223A: Swift detection of a burst
  79. GRB 160221A: Fermi GBM observation
  80. LVC GW 150914: TAROT/TZAC Final analysis correction
  81. GRB 160221A: GROND upper limits
  82. Correction to the title of Swift GCN 19051
  83. GRB 160220B: Further GROND Observations
  84. Further Swift/UVOT observations of GRB 160220B
  85. GRB 160221A: Swift-XRT observations
  86. GRB 160221A: MASTER-SAAO early observations
  87. LVC GW 150914: TAROT/TZAC Final analysis
  88. GRB 160221A: Swift ToO observations
  89. GRB 160221A: A long GRB detected by INTEGRAL
  90. Konus-Wind observation of GRB 160220B
  91. Swift trigger 674752 is likely due to a noise fluctuation
  92. GRB 160220B: Swift-BAT refined analysis
  93. GRB 160220B: GROND Observations
  94. GRB 160219A: Fermi GBM detection
  95. GRB 160220A: nIR observations at AAT
  96. GRB 160220A: Swift-XRT refined Analysis
  97. GRB 160220A: Swift-BAT refined analysis
  98. GRB160220B: Swift/UVOT observations
  99. GRB 160220B: Swift-XRT refined Analysis
  100. IPN Triangulation of GRB 160219A (short/hard)

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