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

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