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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 080804: UVES redshift
  2. GRB 080804: Swift detection of a burst with optical afterglow
  3. GRB 080804: ROTSE-III Detection of Optical Counterpart
  4. GRB 080802: Swift/UVOT Upper Limits
  5. GRB 080802: Swift-XRT Refined Analysis
  6. GRB 080802: UVI Telescope Upper Limit
  7. GRB 080802, Swift-BAT refined analysis
  8. GRB 080802: Swift detection of a probable burst
  9. GRB 080727C: Suzaku WAM observation of the prompt emission
  10. GRB 080727B: IR photometry
  11. GRB 080727A: Early IR observations
  12. GRB 080727C: TAROT Calern observatory optical observations
  13. GRB 080727B: KAIT photometry and an early lightcurve break
  14. GRB 080727B: GROND redshift limit
  15. GRB 080727C, Swift-BAT refined analysis
  16. GRB 080727C: Swift/UVOT Upper Limits
  17. Konus-Wind observation of GRB 080727B
  18. GRB 080727C: Swift XRT refined analysis
  19. GRB 080727C: Liverpool Telescope observations
  20. GRB 080727A: VLT upper limits
  21. GRB 080727C: Enhanced Swift-XRT position
  22. GRB 080727B: REM NIR afterglow prompt detection
  23. GRB080727C: RTT150 optical observations
  24. GRB 080727C: Swift detection of a burst
  25. Swift detection of XTE J1701-407
  26. GRB 080727B: Swift/UVOT Upper Limits
  27. BAT Trigger 318150 is not a GRB
  28. GRB 080727B: Swift-XRT refined analysis
  29. GRB 080727B, Swift-BAT refined analysis
  30. GRB 080727A, Swift-BAT refined analysis
  31. GRB 080727A: Swift-XRT refined analysis
  32. GRB080727A: Swift/UVOT Upper Limits
  33. GRB 080727B: Enhanced Swift-XRT position
  34. GRB 080727A: Enhanced Swift-XRT position
  35. GRB 080727B: KAIT observations
  36. GRB 080727B: REM prompt observations
  37. GRB 080727B: Swift detection of a bright burst
  38. GRB 080727: Swift detection of a burst
  39. GRB 080726: GRB Localization by SuperAGILE
  40. GRB 080725, Swift-BAT refined analysis
  41. GRB 080723A: optical upper limit
  42. GRB080723B: Swift/UVOT Upper Limits
  43. GRB 080725: REM prompt observations
  44. Konus-Wind observation of GRB 080723B
  45. GRB 080725: Swift detection of a burst
  46. ATCA radio upper limit on GRB 080723B
  47. GRB 080723A: Swift/UVOT Upper Limits
  48. VLA radio upper limit on GRB 080721
  49. GRB 080723B - correction to flux conversion factor
  50. GRB 080723B - Swift-XRT refined analysis
  51. GRB 080723B - Swift-XRT position
  52. GRB 080723, Swift-BAT refined analysis
  53. GRB 080723B: AGILE GRID and MCAL results
  54. GRB 080723B : Planned XMM-Newton observation
  55. GRB 080723A: Swift-XRT refined analysis
  56. GRB 080723B: Detection and Localization by SuperAGILE
  57. GRB 080723B : a long GRB detected with INTEGRAL
  58. GRB 080723: Enhanced Swift-XRT position
  59. GRB 080723: Swift detection of a burst
  60. GRB 080721 : Lulin 2nd optical follow-ups
  61. GRB 080721: OA fading and redshift
  62. TNG/DOLORES redshift for GRB080721
  63. GRB 080721: UVOT Follow-Up Observations
  64. Konus-Wind observation of GRB 080721
  65. GRB 080721: Swift-XRT refined analysis
  66. GRB 080721: Enhanced Swift-XRT position
  67. GRB 080721, Swift-BAT refined analysis
  68. GRB 080721: Swift/UVOT Photometric Redshift
  69. GRB 080721 : Lulin Optical follow-ups
  70. GRB 080721: Swift-XRT correct position
  71. GRB 080721: Swift detection of a burst with a bright optical counterpart.
  72. Retraction of Swift Trigger 317393
  73. Trigger 317393: Swift detection of a possible GRB
  74. Trigger 317205: Swift detection of an outburst from XTE J1701-407
  75. GRB 080714: GROND confirmation of the optical/NIR afterglow
  76. Konus-Wind observation of GRB 080714
  77. GRB 080714: Swift/UVOT Detection of an Optical Afterglow
  78. GRB 080714: Swift-XRT refined analysis
  79. GRB 080714: Enhanced Swift-XRT position
  80. GRB 080714: Swift-BAT refined analysis
  81. GRB 080714: Swift detection of a burst
  82. GRB 080702A: optical upper limit
  83. GRB 080603A: CrAO optical observations
  84. GRB 080603B: optical observations in MAO
  85. GRB 080603B: optical observations in CrAO
  86. GRB 080710: Optical observation with MITSuME Okayama
  87. GRB 080710: TLS observations, steepening afterglow decay
  88. GRB 080702B: Swift XRT confirmation of the afterglow
  89. GRB 080710: Lick IR detection
  90. GRB 080710, Swift-BAT refined analysis
  91. GRB 0800707: optical observations
  92. GRB 080710: Rapid PROMPT Observations
  93. GRB 080710: Swift-XRT refined analysis
  94. GRB080710: Swift/UVOT observations
  95. GRB 080710: Enhanced Swift-XRT position
  96. GRB 080710: Faulkes Telescope North observations
  97. GRB 080710: Gemini spectroscopy and probable redshift
  98. UVOT white band observations of GRB080710
  99. GRB 080710: REM afterglow confirmation & brightening
  100. GRB 080710: KAIT OA candidate

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