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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. Swift-BAT spectral lag analysis of GRB 080413B
  2. GRB 080413a, SMARTS optical/IR afterglow observations
  3. GRB 080413B: Swift XRT refined analysis
  4. GRB080413A: Swift/UVOT observations
  5. GRB 080413B, Swift-BAT refined analysis
  6. GRB 080413A: Swift-XRT refined analysis
  7. GRB 080413A, Swift-BAT refined analysis
  8. GRB 080413A Bootes observation
  9. GRB 080413A: VLT/UVES redshift
  10. GRB 080413B: VLT redshift
  11. GRB080413B: REM NIR & Optical Observation
  12. GRB 080413B: GROND detection of afterglow in all bands
  13. GRB 080413B: Swift detection of a possibly short burst with optical counterpart
  14. GRB 080413A: REM detection of the NIR Afterglow
  15. GRB 080413: Enhanced Swift-XRT position
  16. GRB 080413: TAROT Calern observatory optical observations
  17. GRB 080413: Swift detection of a burst with an optical afterglow
  18. GRB 080413: ROTSE-III Detection of Optical Counterpart
  19. GRB 080411: Swift/UVOT refined analysis
  20. GRB 080411, Swift-BAT refined analysis
  21. GRB 080411: Swift-XRT Refined Analysis
  22. Konus-Wind observation of GRB 080411
  23. GRB 080411: Enhanced Swift-XRT position
  24. GRB 080411: VLT redshift
  25. GRB 080411: GROND detection of optical afterglow candidate
  26. GRB080330: MAGIC telescope GeV observation
  27. GRB 080411: Swift detection of a bright burst
  28. GRB 080330: Swift-XRT refined position retraction
  29. GRB 080409: Swift-BAT refined analysis
  30. GRB 080408: GROND detection of optical/NIR afterglow candidate
  31. GRB 080330 optical observations
  32. Swift/UVOT observations of GRB080409
  33. GRB 080409: Swift XRT refined analysis
  34. UVOT/Swift Observations of GRB080408
  35. GRB 080408: Swift-XRT position of a possible afterglow
  36. GRB 080409: Enhanced Swift-XRT position
  37. GRB 080409: REM optical/NIR observations
  38. GRB 080409: Swift detection of a burst
  39. GRB 080408: Analysis of AGILE Gamma-ray data
  40. GRB 080408: GRB Localization by SuperAGILE
  41. GRB 080319A: Early RAPTOR optical limits
  42. GRB 080319B: HST observations
  43. GRB 080330: RAPTOR detection of prompt optical flash
  44. GRB 080319B: Potential Jet Break Observed by Swift-XRT and UVOT
  45. GRB 080405: Swift-BAT refined analysis
  46. GRB 080405: Swift-XRT position
  47. GRB 080405: Mars Oddysey and Swift-BAT detection, possible host galaxy
  48. GRB 080325: optical upper limit
  49. GRB 080328: GAO 150cm telescope Optical Observation
  50. GRB080330: Improved Swift XRT Position
  51. GRB 080330: Prompt PROMPT Observations
  52. GRB080330: optical observations
  53. GRB 080319B: TORTORA light curve (Correction)
  54. GRB080328, RIMOTS optical upper limit
  55. GRB080330: optical observations
  56. GRB080330: Swift XRT refined analysis
  57. GRB 080330: REM optical observations
  58. GRB 080330, SMARTS optical/IR afterglow observations
  59. GRB 080330 Swift-UVOT refined analysis
  60. GRB 080328: Suzaku WAM observation of the prompt emission
  61. GRB080330: TNT optical observations
  62. GRB 080330, Swift-BAT refined analysis
  63. Konus-Wind observation of GRB 080328
  64. GRB 080330: Redshift Confirmation from Hobby-Eberly Telescope Spectroscopy
  65. GRB080330: LOAO R-band Detection
  66. GRB 080330: GROND Observations
  67. GRB 080330: NOT redshift
  68. GRB 080330: TAROT Calern observatory optical observations
  69. GRB 080330A: PAIRITEL Infrared Detections
  70. GRB 080330: error in reported XRT position
  71. GRB080330 - SDSS Pre-Burst Observations
  72. GRB 080330: Liverpool Telescope Optical observations
  73. GRB 080330A: ROTSE-III Detection of Optical Counterpart
  74. GRB 080330: Swift detection of a burst with an optical counterpart
  75. GRB 080330: TAROT Calern observatory optical detection
  76. GRB 080319B: Continued Gemini-South followup and possible host galaxy
  77. GRB 080328: BTA optical imaging and spectroscopy
  78. GRB 080328, Swift-BAT refined analysis
  79. GRB 080328: Swift XRT refined analysis
  80. GRB 080325, Swift-BAT refined analysis
  81. Swift/UVOT observations of GRB080328
  82. GRB080325 - I and z-band Imaging
  83. GRB080319B, BVRcIc field calibration
  84. GRB 080328: Enhanced Swift-XRT position
  85. GRB080328: Faulkes Telescope North observations
  86. GRB 080328: Swift detection of a burst with an optical counterpart
  87. GRB 080325: Subaru detection of NIR afterglow candidate
  88. GRB080310, late-time photometry with LBT
  89. GRB 080325: MITSuME Akeno optical upper limits
  90. GRB080325: XRT Refined Analysis
  91. GRB 080325: GROND Observations
  92. GRB080319B: optical observations
  93. GRB 080325: Swift/UVOT Upper Limits
  94. GRB 080319C: Gemini-North spectroscopic redshift
  95. GRB 080325: Early observations from OSN
  96. GRB 080325: NIR afterglow candidate
  97. GRB 080319D: GROND Detection of the Optical Counterpart
  98. GRB 080325: Enhanced Swift-XRT position
  99. GRB 080325: Swift detection of a burst
  100. GRB 080319B : Apparent spectral evolution in very early Swift/XRT WT mode data: intrinsic or pile-up effect?

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