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"

19538 results found.

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

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