Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

18435 results found.

  1. Fermi LAT detection of GRB 090510
  2. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  3. GRB 090510: Swift detection of a short hard burst
  4. GRB 090408: optical upper limit
  5. GRB 090418A: optical observation
  6. GRB 090509: GROND afterglow candidate
  7. GRB 090509: Swift detection of a burst
  8. GRB 090423: optical limit
  9. GRB 090424: optical observations
  10. GRB 090429A: ROVOR magnitude limit
  11. GRB 090426: optical observations
  12. GRB 090429D: Fermi GBM detection
  13. GRB 090429B: Swift/UVOT Upper Limits
  14. GRB 090429A: Swift/UVOT Upper Limits
  15. GRB 090429A: Swift-XRT refined analysis
  16. GRB 090429A: GROND upper limits
  17. GRB 090429B: Swift XRT refined analysis
  18. GRB 090429A: Enhanced Swift-XRT position
  19. GRB 090429B: RIMOTS optical upper limits
  20. GRB 090429B: Swift-BAT refined analysis
  21. GRB 090429A: Swift-BAT refined analysis
  22. GRB 090429B: Enhanced Swift-XRT position
  23. GRB 090429A - Correction to XRT position
  24. GRB090429B: Gemini-N infrared IR candidate
  25. GRB 090429B: GROND Observations
  26. GRB 090429B: Swift detection of a burst
  27. GRB 090429: Swift detection of a burst
  28. GRB 090424 : Multiband Optical observation from Nainital
  29. GRB 090423: CARMA mm observations
  30. GRB 090423: millimeter detection
  31. GRB 090426: Swift/BAT spectral lag results
  32. GRB 090424: Suzaku WAM observation of the prompt emission
  33. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  34. GRB090426 Swift/UVOT observations
  35. GRB 090426: Swift-BAT refined analysis
  36. GRB 090426: Swift-XRT refined analysis
  37. GRB 090423: GROND second epoch imaging and refined SED
  38. GRB 090426: Enhanced Swift-XRT position
  39. GRB 090426, RIMOTS optical upper limits
  40. GRB 090426: TNT confimation of optical counterpart
  41. GRB 090426: Swift detection of a burst with an optical counterpart
  42. GRB 090424: MASTER-Net prompt optical limit
  43. VLA radio observation of high-z GRB 090423
  44. GRB 090424: THO optical observations
  45. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  46. GRB 090423: Swift/BAT spectral lag results
  47. GRB 090424: Swift-XRT refined analysis
  48. GRB 090423: energetic, luminosity and jet break
  49. Swift/UVOT observations of GRB 090424
  50. GRB 090424: Enhanced Swift-XRT position
  51. GRB 090424: Swift-BAT refined analysis
  52. GRB 090424: Fermi GBM Observation
  53. GRB 090423: Fermi GBM observation
  54. GRB 090422: Fermi GBM observation
  55. GRB 090423: Ep,i - Eiso correlation
  56. GRB 090424: SDSS Galaxy at the Swift position
  57. GRB 090424: TNT optical observations
  58. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  59. GRB 090424: Swift detection of a burst with an optical counterpart
  60. GRB 090423: GROND detection and preliminary photo-z
  61. GRB 090423: Swift-XRT refined analysis
  62. GRB090423 - Swift/UVOT upper limits.
  63. GRB 090423: NIR photometry and evidence for spectral break
  64. GRB 090422: Swift-XRT refined analysis
  65. GRB090423, RIMOTS optical upper limits
  66. GRB 090423: Enhanced Swift-XRT position
  67. GRB 090423: Swift-BAT refined analysis
  68. GRB 090422: Swift/UVOT Upper Limits
  69. GRB 090423: Faulkes Telescope South observations
  70. GRB 090418A: R and I band observation
  71. GRB 090423: Swift detection of a burst
  72. GRB 090422: Liverpool Telescope possible candidate
  73. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  74. GRB 090422: Swift-BAT refined analysis
  75. GRB 090422: Enhanced Swift-XRT position
  76. GRB 090422: Liverpool Telescope observations
  77. GRB 090422: Swift detection of a burst
  78. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  79. Swift-BAT trigger 349718 is not a burst
  80. GRB 090417B: Optical observation
  81. GRB 090418A: optical observations
  82. GRB 090419: Swift/UVOT Observations
  83. GRB 090418B: Faulkes Telescope North observations
  84. GRB 090418A: Swift/UVOT Observations
  85. GRB 090417B: Swift/UVOT Upper Limits
  86. GRB 090417B Correction to the BAT refined analysis position
  87. GRB 090419: Swift-XRT refined analysis
  88. Konus-Wind observation of GRB 090418B
  89. GRB 090419: GROND detection of afterglow candidate
  90. GRB 090419: Swift-BAT refined analysis
  91. VLA radio upper limit on GRB 090417B
  92. GRB 090419: Enhanced Swift-XRT position
  93. GRB 090418: Swift XRT refined analysis
  94. GRB 090418A: ROTSE-III Refined Analysis
  95. GRB 090419: Swift detection of a burst
  96. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  97. GRB 090418: Swift-BAT refined analysis
  98. GRB 090417B: Swift-XRT refined analysis
  99. GRB 090418: Enhanced Swift-XRT position
  100. GRB 090417B: Swift-BAT further 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