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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 080727C: Liverpool Telescope observations
  2. GRB 080727A: VLT upper limits
  3. GRB 080727C: Enhanced Swift-XRT position
  4. GRB 080727B: REM NIR afterglow prompt detection
  5. GRB080727C: RTT150 optical observations
  6. GRB 080727C: Swift detection of a burst
  7. Swift detection of XTE J1701-407
  8. GRB 080727B: Swift/UVOT Upper Limits
  9. BAT Trigger 318150 is not a GRB
  10. GRB 080727B: Swift-XRT refined analysis
  11. GRB 080727B, Swift-BAT refined analysis
  12. GRB 080727A, Swift-BAT refined analysis
  13. GRB 080727A: Swift-XRT refined analysis
  14. GRB080727A: Swift/UVOT Upper Limits
  15. GRB 080727B: Enhanced Swift-XRT position
  16. GRB 080727A: Enhanced Swift-XRT position
  17. GRB 080727B: KAIT observations
  18. GRB 080727B: REM prompt observations
  19. GRB 080727B: Swift detection of a bright burst
  20. GRB 080727: Swift detection of a burst
  21. GRB 080726: GRB Localization by SuperAGILE
  22. GRB 080725, Swift-BAT refined analysis
  23. GRB 080723A: optical upper limit
  24. GRB080723B: Swift/UVOT Upper Limits
  25. GRB 080725: REM prompt observations
  26. Konus-Wind observation of GRB 080723B
  27. GRB 080725: Swift detection of a burst
  28. ATCA radio upper limit on GRB 080723B
  29. GRB 080723A: Swift/UVOT Upper Limits
  30. VLA radio upper limit on GRB 080721
  31. GRB 080723B - correction to flux conversion factor
  32. GRB 080723B - Swift-XRT refined analysis
  33. GRB 080723B - Swift-XRT position
  34. GRB 080723, Swift-BAT refined analysis
  35. GRB 080723B: AGILE GRID and MCAL results
  36. GRB 080723B : Planned XMM-Newton observation
  37. GRB 080723A: Swift-XRT refined analysis
  38. GRB 080723B: Detection and Localization by SuperAGILE
  39. GRB 080723B : a long GRB detected with INTEGRAL
  40. GRB 080723: Enhanced Swift-XRT position
  41. GRB 080723: Swift detection of a burst
  42. GRB 080721 : Lulin 2nd optical follow-ups
  43. GRB 080721: OA fading and redshift
  44. TNG/DOLORES redshift for GRB080721
  45. GRB 080721: UVOT Follow-Up Observations
  46. Konus-Wind observation of GRB 080721
  47. GRB 080721: Swift-XRT refined analysis
  48. GRB 080721: Enhanced Swift-XRT position
  49. GRB 080721, Swift-BAT refined analysis
  50. GRB 080721: Swift/UVOT Photometric Redshift
  51. GRB 080721 : Lulin Optical follow-ups
  52. GRB 080721: Swift-XRT correct position
  53. GRB 080721: Swift detection of a burst with a bright optical counterpart.
  54. Retraction of Swift Trigger 317393
  55. Trigger 317393: Swift detection of a possible GRB
  56. Trigger 317205: Swift detection of an outburst from XTE J1701-407
  57. GRB 080714: GROND confirmation of the optical/NIR afterglow
  58. Konus-Wind observation of GRB 080714
  59. GRB 080714: Swift/UVOT Detection of an Optical Afterglow
  60. GRB 080714: Swift-XRT refined analysis
  61. GRB 080714: Enhanced Swift-XRT position
  62. GRB 080714: Swift-BAT refined analysis
  63. GRB 080714: Swift detection of a burst
  64. GRB 080702A: optical upper limit
  65. GRB 080603A: CrAO optical observations
  66. GRB 080603B: optical observations in MAO
  67. GRB 080603B: optical observations in CrAO
  68. GRB 080710: Optical observation with MITSuME Okayama
  69. GRB 080710: TLS observations, steepening afterglow decay
  70. GRB 080702B: Swift XRT confirmation of the afterglow
  71. GRB 080710: Lick IR detection
  72. GRB 080710, Swift-BAT refined analysis
  73. GRB 0800707: optical observations
  74. GRB 080710: Rapid PROMPT Observations
  75. GRB 080710: Swift-XRT refined analysis
  76. GRB080710: Swift/UVOT observations
  77. GRB 080710: Enhanced Swift-XRT position
  78. GRB 080710: Faulkes Telescope North observations
  79. GRB 080710: Gemini spectroscopy and probable redshift
  80. UVOT white band observations of GRB080710
  81. GRB 080710: REM afterglow confirmation & brightening
  82. GRB 080710: KAIT OA candidate
  83. GRB 080710: Swift XRT position
  84. GRB 080710: Swift detection of a burst
  85. GRB 080707: possible break in the X-rays
  86. New Swift-XRT GRB products available online.
  87. GRB 080707: GROND Confirmation of the Optical Afterglow
  88. UVOT observations of GRB080707
  89. GRB 080707, Swift-BAT refined analysis
  90. GRB 080707: Swift XRT refined analysis
  91. GRB 080707: Enhanced Swift-XRT position
  92. GRB 080707: VLT redshift
  93. GRB 080707: GROND Detection of the Optical Afterglow Candidate
  94. GRB 080707: Swift detection of a burst
  95. Refined analysis of Swift Trigger 316063, is IGR J08408-4503
  96. Trigger 316063: Swift detection of a transient
  97. GRB 080703: GROND Upper Limits
  98. GRB 080702B: GROND Upper Limits
  99. GRB 080703: Swift-XRT refined analysis
  100. GRB 080703: UVOT Follow-Up Observation

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