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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').
  1. GRB050408: Radio Observations
  2. GRB 050408: Swift XRT analysis
  3. GRB 050408, SMARTS optical/IR afterglow observations
  4. GRB 050408: Optical limit at 20 min after the burst
  5. GRB 050408, optical observations
  6. GRB050408: REM NIR and Optical observation
  7. GRB 050408: Moderate-resolution Gemini Spectroscopy
  8. GRB 050408,optical observation
  9. GRB 050408 Optical Observations
  10. GRB 050408: Emission and absorption redshift
  11. GRB 050408: Mercator Optical Observations
  12. GRB 050408: Magellan astrometry and photometry
  13. GRB 050408: First Optical observations with TFOSC at the RTT150
  14. GRB 050408: steepening of the optical decay
  15. GRB 050408: Optical afterglow confirmed
  16. GRB 050408: opitcal observation
  17. GRB 050408, optical observations
  18. GRB 050408 optical candidate
  19. GRB 050408: Swift XRT Position
  20. GRB 050408: ROTSE-III Optical Limits
  21. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  22. GRB050408: MASTER optical observations
  23. GRB050401: Radio Detection
  24. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  25. GRB 050406: Magellan optical observations
  26. GRB 050406: early Swift XRT analysis results
  27. GRB 050406 BAT refined analysis
  28. GRB 050406: Early observations with Swift-UVOT
  29. GRB 050406: Swift XRT Position
  30. Swift-BAT detection of GRB 050406
  31. Konus-Wind observation of GRB 050401
  32. GRB050401: Radio observation at 610 MHz with GMRT
  33. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  34. GRB 050401: VLT spectroscopic redshift
  35. GRB 050401 Optical Observations
  36. GRB050401: Maidanak optical observation
  37. GRB 050401 BAT refined analysis
  38. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  39. GRB050401: TNG R-band observation
  40. GRB 050402A: IR Analysis
  41. GRB050402: XDSS counterpart
  42. GRB 050402A: IR Observations
  43. GRB 050402: Early observations with Swift-UVOT
  44. Swift Trigger 113225: P60 Observations
  45. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  46. GRB 050401: Optical afterglow confirmed
  47. GRB 050401: Optical afterglow candidate
  48. Swift-BAT detection of GRB 050401
  49. GRB 050401: Prompt XRT position
  50. Retraction of three Swift GRB triggers
  51. GRB050331: No Afterglow Detected
  52. Swift-BAT detection of GRB 050331b
  53. GRB 050331: Swift UVOT Source
  54. Swift-BAT detection of GRB 050331
  55. GRB 050331: Swift XRT Position
  56. Swift Data Publicly Available Starting April 5, 2005
  57. GRB050319: radio observation
  58. Konus-Wind observation of GRB 050326
  59. GRB050326: optical limit
  60. GRB 050326: Early observations with Swift-UVOT
  61. GRB 050326 XMM-Newton observation
  62. GRB 050326 : Planned XMM-Newton observation
  63. GRB 050326: Swift XRT Position
  64. GRB050326: optical limit 33min before GRB
  65. GRB 050326 BAT refined analysis
  66. GRB050326: delayed XRT observation
  67. Swift-BAT detection of a bright GRB 050326
  68. GRB050319, optical observations
  69. GRB050319, color indices
  70. GRB050319: optical observation, March 20-22
  71. GRB050319: RTT150 Optical Observations
  72. Swift-BAT detection of a bright outburst from SGR1806-20
  73. Swift-BAT trigger 112060 is not a real GRB
  74. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  75. GRB 050319: ROTSE-III Refined Analysis
  76. GRB 050318: Swift-BAT refined analysis
  77. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  78. GRB050319: VLA Observations
  79. GRB050319: radio observation
  80. GRB 050319 R band observations
  81. GRB 050319: Swift-UVOT detection of the afterglow
  82. GRB 050315: Variability Analysis of Swift BAT Time History
  83. GRB050319: Radio Observations
  84. GRB 050319: NIR afterglow candidate
  85. GRB 050319:Near IR afterglow
  86. GRB050319: BR optical photometry
  87. GRB 050318: SWIFT-UVOT refined analysis
  88. GRB 050318: Absorption redshift from Magellan
  89. GRB 050319: Optical observation
  90. GRB 050319 : Confirmation of optical afterglow decay
  91. GRB 050319: Swift-BAT refined analysis
  92. GRB050319,optical observation
  93. Swift Detection of GRB 050319
  94. GRB 050319: Detection of Possible Optical Counterpart
  95. GRB 050318: Swift/UVOT detection of afterglow emission
  96. GRB 050318: Magellan optical afterglow identification
  97. GRB050318: Swift XRT position
  98. RXTE Observations of GRB050318
  99. Swift-BAT detection of GRB 050318
  100. GRB 050315, SMARTS optical afterglow decay

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