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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 080405: Swift-XRT position
  2. GRB 080405: Mars Oddysey and Swift-BAT detection, possible host galaxy
  3. GRB 080325: optical upper limit
  4. GRB 080328: GAO 150cm telescope Optical Observation
  5. GRB080330: Improved Swift XRT Position
  6. GRB 080330: Prompt PROMPT Observations
  7. GRB080330: optical observations
  8. GRB 080319B: TORTORA light curve (Correction)
  9. GRB080328, RIMOTS optical upper limit
  10. GRB080330: optical observations
  11. GRB080330: Swift XRT refined analysis
  12. GRB 080330: REM optical observations
  13. GRB 080330, SMARTS optical/IR afterglow observations
  14. GRB 080330 Swift-UVOT refined analysis
  15. GRB 080328: Suzaku WAM observation of the prompt emission
  16. GRB080330: TNT optical observations
  17. GRB 080330, Swift-BAT refined analysis
  18. Konus-Wind observation of GRB 080328
  19. GRB 080330: Redshift Confirmation from Hobby-Eberly Telescope Spectroscopy
  20. GRB080330: LOAO R-band Detection
  21. GRB 080330: GROND Observations
  22. GRB 080330: NOT redshift
  23. GRB 080330: TAROT Calern observatory optical observations
  24. GRB 080330A: PAIRITEL Infrared Detections
  25. GRB 080330: error in reported XRT position
  26. GRB080330 - SDSS Pre-Burst Observations
  27. GRB 080330: Liverpool Telescope Optical observations
  28. GRB 080330A: ROTSE-III Detection of Optical Counterpart
  29. GRB 080330: Swift detection of a burst with an optical counterpart
  30. GRB 080330: TAROT Calern observatory optical detection
  31. GRB 080319B: Continued Gemini-South followup and possible host galaxy
  32. GRB 080328: BTA optical imaging and spectroscopy
  33. GRB 080328, Swift-BAT refined analysis
  34. GRB 080328: Swift XRT refined analysis
  35. GRB 080325, Swift-BAT refined analysis
  36. Swift/UVOT observations of GRB080328
  37. GRB080325 - I and z-band Imaging
  38. GRB080319B, BVRcIc field calibration
  39. GRB 080328: Enhanced Swift-XRT position
  40. GRB080328: Faulkes Telescope North observations
  41. GRB 080328: Swift detection of a burst with an optical counterpart
  42. GRB 080325: Subaru detection of NIR afterglow candidate
  43. GRB080310, late-time photometry with LBT
  44. GRB 080325: MITSuME Akeno optical upper limits
  45. GRB080325: XRT Refined Analysis
  46. GRB 080325: GROND Observations
  47. GRB080319B: optical observations
  48. GRB 080325: Swift/UVOT Upper Limits
  49. GRB 080319C: Gemini-North spectroscopic redshift
  50. GRB 080325: Early observations from OSN
  51. GRB 080325: NIR afterglow candidate
  52. GRB 080319D: GROND Detection of the Optical Counterpart
  53. GRB 080325: Enhanced Swift-XRT position
  54. GRB 080325: Swift detection of a burst
  55. GRB 080319B : Apparent spectral evolution in very early Swift/XRT WT mode data: intrinsic or pile-up effect?
  56. IBAS Alert n. 5245: NOT a GRB
  57. GRB 080319B: Spitzer Mid-infrared Observations
  58. GRB 080319C: Suzaku WAM observation of the prompt emission
  59. GRB 080319B: Second & Third Epoch WSRT Radio Observations
  60. Radio Detection of GRB 080319B
  61. GRB 080320, Swift-BAT refined analysis
  62. GRB 080319B: Optical observation (Brno, CZ)
  63. GRB 080319D: GROND Observations
  64. GRB 080319B: TORTORA light curve
  65. GRB 080319B: optical upper limit
  66. GRB 080319D: optical upper limit
  67. GRB080319B: Time-Independent XRT Spectrum
  68. GRB 080319D, Swift-BAT refined analysis
  69. GRB 080319C: UVOT Observations
  70. GRB 080319B: UVOT Observations
  71. GRB 080319A: UVOT Observations
  72. GRB 080320: Swift XRT refined analysis
  73. GRB 080319B - CARMA mm Observations
  74. GRB 080320: Early Super-LOTIS Observations
  75. GRB 080320: J detection with FLAMINGOS
  76. GRB 080319D: Swift XRT refined analysis
  77. GRB 080320: optical limit
  78. GRB 080320: Gemini-N optical afterglow
  79. Konus-Wind observation of GRB 080319C
  80. GRB 080319B: Gemini-South photometry
  81. GRB 080319B: Allen Telescope Array Observations
  82. GRB 080319B optical observations
  83. GRB 080319C, Swift-BAT refined analysis
  84. Konus-Wind observation of GRB 080319B
  85. GRB 080319B: WSRT Radio Observations
  86. GRB 080320: SDSS source and Gemini-N observations
  87. GRB 080320: Enhanced Swift-XRT position
  88. GRB 080320: optical limit from IAC80
  89. GRB 080319C: Early RAPTOR Observations
  90. GRB 080319B: second epoch imaging from Canarias (correction to GCN7469)
  91. GRB 080319C: KAIT OA observations
  92. GRB 080320 - SDSS Pre-Burst Observations
  93. GRB 080320: Swift detection of a burst
  94. GRB 080320: ROTSE-III Optical Limits
  95. GRB 080319B : Lulin observation of temporal break at 0.2 days
  96. GRB 080319B: ROTSE-III Observations of Optical Counterpart
  97. GRB 080319B: optical observations
  98. GRB 080319C - SDSS Pre-Burst Observations
  99. GRB 080319A SDSS Pre-Burst Observations
  100. Swift-BAT trigger 306829 is IGR J16479-4514

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