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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 080723B - correction to flux conversion factor
  2. GRB 080723B - Swift-XRT refined analysis
  3. GRB 080723B - Swift-XRT position
  4. GRB 080723, Swift-BAT refined analysis
  5. GRB 080723B: AGILE GRID and MCAL results
  6. GRB 080723B : Planned XMM-Newton observation
  7. GRB 080723A: Swift-XRT refined analysis
  8. GRB 080723B: Detection and Localization by SuperAGILE
  9. GRB 080723B : a long GRB detected with INTEGRAL
  10. GRB 080723: Enhanced Swift-XRT position
  11. GRB 080723: Swift detection of a burst
  12. GRB 080721 : Lulin 2nd optical follow-ups
  13. GRB 080721: OA fading and redshift
  14. TNG/DOLORES redshift for GRB080721
  15. GRB 080721: UVOT Follow-Up Observations
  16. Konus-Wind observation of GRB 080721
  17. GRB 080721: Swift-XRT refined analysis
  18. GRB 080721: Enhanced Swift-XRT position
  19. GRB 080721, Swift-BAT refined analysis
  20. GRB 080721: Swift/UVOT Photometric Redshift
  21. GRB 080721 : Lulin Optical follow-ups
  22. GRB 080721: Swift-XRT correct position
  23. GRB 080721: Swift detection of a burst with a bright optical counterpart.
  24. Retraction of Swift Trigger 317393
  25. Trigger 317393: Swift detection of a possible GRB
  26. Trigger 317205: Swift detection of an outburst from XTE J1701-407
  27. GRB 080714: GROND confirmation of the optical/NIR afterglow
  28. Konus-Wind observation of GRB 080714
  29. GRB 080714: Swift/UVOT Detection of an Optical Afterglow
  30. GRB 080714: Swift-XRT refined analysis
  31. GRB 080714: Enhanced Swift-XRT position
  32. GRB 080714: Swift-BAT refined analysis
  33. GRB 080714: Swift detection of a burst
  34. GRB 080702A: optical upper limit
  35. GRB 080603A: CrAO optical observations
  36. GRB 080603B: optical observations in MAO
  37. GRB 080603B: optical observations in CrAO
  38. GRB 080710: Optical observation with MITSuME Okayama
  39. GRB 080710: TLS observations, steepening afterglow decay
  40. GRB 080702B: Swift XRT confirmation of the afterglow
  41. GRB 080710: Lick IR detection
  42. GRB 080710, Swift-BAT refined analysis
  43. GRB 0800707: optical observations
  44. GRB 080710: Rapid PROMPT Observations
  45. GRB 080710: Swift-XRT refined analysis
  46. GRB080710: Swift/UVOT observations
  47. GRB 080710: Enhanced Swift-XRT position
  48. GRB 080710: Faulkes Telescope North observations
  49. GRB 080710: Gemini spectroscopy and probable redshift
  50. UVOT white band observations of GRB080710
  51. GRB 080710: REM afterglow confirmation & brightening
  52. GRB 080710: KAIT OA candidate
  53. GRB 080710: Swift XRT position
  54. GRB 080710: Swift detection of a burst
  55. GRB 080707: possible break in the X-rays
  56. New Swift-XRT GRB products available online.
  57. GRB 080707: GROND Confirmation of the Optical Afterglow
  58. UVOT observations of GRB080707
  59. GRB 080707, Swift-BAT refined analysis
  60. GRB 080707: Swift XRT refined analysis
  61. GRB 080707: Enhanced Swift-XRT position
  62. GRB 080707: VLT redshift
  63. GRB 080707: GROND Detection of the Optical Afterglow Candidate
  64. GRB 080707: Swift detection of a burst
  65. Refined analysis of Swift Trigger 316063, is IGR J08408-4503
  66. Trigger 316063: Swift detection of a transient
  67. GRB 080703: GROND Upper Limits
  68. GRB 080702B: GROND Upper Limits
  69. GRB 080703: Swift-XRT refined analysis
  70. GRB 080703: UVOT Follow-Up Observation
  71. GRB 080703: VLT observations of the afterglow
  72. GRB 080703: Enhanced Swift-XRT position
  73. GRB 080703, Swift-BAT refined analysis
  74. GRB 080702B Swift-BAT refined analysis
  75. GRB 080703: Swift detection of a burst with optical afterglow
  76. GRB 080703A: ROTSE-III Detection of Optical Counterpart
  77. No radio detection from the short GRB 080702A
  78. GRB 080702b: LCO optical observations
  79. Swift/UVOT observation of GRB080702A
  80. GRB 080702B: Swift XRT and UVOT observations
  81. GRB 080625: Suzaku WAM observation of the prompt emission
  82. GRB 080702A: MITSuME Akeno optical upper limits
  83. GRB 080701A: Early RAPTOR optical limits
  84. Swift Trigger 315630: Swift/UVOT Upper Limits
  85. GRB 080702A, Swift-BAT refined analysis
  86. GRB 080702A: Swift-XRT Team refined analysis
  87. GRB 080702B : Burst detected in BAT during Swift slew
  88. GRB 080702A: Enhanced Swift-XRT position
  89. Swift Trigger 315630: TLS R-band observation
  90. Swift Trigger 315630: Probably not a GRB
  91. GRB 080702: Swift detection of a short burst
  92. GRB 080701: Swift-XRT refined analysis
  93. GRB 080701A, VATT optical upper limit
  94. TLS I-Band Observation of GRB 080701A
  95. GRB 080701A: Swift/UVOT Upper Limits
  96. GRB 080701A: Early Super-LOTIS Observations
  97. GRB 080701: Enhanced Swift-XRT position
  98. GRB 080701A, Swift-BAT refined analysis
  99. Trigger 315630: Swift detection of a possible burst
  100. GRB 080701: Swift-XRT Prompt Analysis

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