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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. GRB 050412: LCO Optical Observations
  2. GRB 050412: Optical observations
  3. GRB050412: P60 Observations
  4. GRB 050412: Swift XRT Position
  5. GRB050412: optical limit before and during GRB
  6. GRB 050412: LCO optical observations
  7. GRB050412: ROTSE-III Optical Limits
  8. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  9. GRB 050412: IR and Optical observations
  10. GRB 050412: IR Observations
  11. GRB050408: Radio Observations
  12. GRB 050401: Optical limit
  13. GRB 050408: Optical limit
  14. GRB050410: P60 Observations
  15. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  16. GRB 050410, optical observations
  17. GRB 050408: PROMPT VRcIc Observations
  18. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  19. GRB 050410 R band Optical Observations
  20. GRB050410 : Null detection report
  21. GRB 050410, optical observations
  22. GRB050410: Radio Observations
  23. GRB 050408: Swift XRT measurement of possible jet break
  24. GRB050410: MASTER optical observations
  25. GRB 050410: Early observations with Swift-UVOT
  26. Swift-BAT detection of GRB 050410
  27. GRB 050410: Swift XRT Position
  28. GRB 050408: Retraction of Proposed Host Galaxy
  29. GRB 050408: Inconsistency of host galaxy identification
  30. GRB 050408: Subaru Observations
  31. GRB 050408: WIDGET simultaneous optical observations
  32. GRB 050408: SOAR UBVRc Observations
  33. GRB 050408: Properties of the Host Galaxy
  34. GRB 050408: Mercator Optical Observations
  35. GRB050408: Radio Observations
  36. GRB 050408: Swift XRT analysis
  37. GRB 050408, SMARTS optical/IR afterglow observations
  38. GRB 050408: Optical limit at 20 min after the burst
  39. GRB 050408, optical observations
  40. GRB050408: REM NIR and Optical observation
  41. GRB 050408: Moderate-resolution Gemini Spectroscopy
  42. GRB 050408,optical observation
  43. GRB 050408 Optical Observations
  44. GRB 050408: Emission and absorption redshift
  45. GRB 050408: Mercator Optical Observations
  46. GRB 050408: Magellan astrometry and photometry
  47. GRB 050408: First Optical observations with TFOSC at the RTT150
  48. GRB 050408: steepening of the optical decay
  49. GRB 050408: Optical afterglow confirmed
  50. GRB 050408: opitcal observation
  51. GRB 050408, optical observations
  52. GRB 050408 optical candidate
  53. GRB 050408: Swift XRT Position
  54. GRB 050408: ROTSE-III Optical Limits
  55. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  56. GRB050408: MASTER optical observations
  57. GRB050401: Radio Detection
  58. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  59. GRB 050406: Magellan optical observations
  60. GRB 050406: early Swift XRT analysis results
  61. GRB 050406 BAT refined analysis
  62. GRB 050406: Early observations with Swift-UVOT
  63. GRB 050406: Swift XRT Position
  64. Swift-BAT detection of GRB 050406
  65. Konus-Wind observation of GRB 050401
  66. GRB050401: Radio observation at 610 MHz with GMRT
  67. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  68. GRB 050401: VLT spectroscopic redshift
  69. GRB 050401 Optical Observations
  70. GRB050401: Maidanak optical observation
  71. GRB 050401 BAT refined analysis
  72. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  73. GRB050401: TNG R-band observation
  74. GRB 050402A: IR Analysis
  75. GRB050402: XDSS counterpart
  76. GRB 050402A: IR Observations
  77. GRB 050402: Early observations with Swift-UVOT
  78. Swift Trigger 113225: P60 Observations
  79. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  80. GRB 050401: Optical afterglow confirmed
  81. GRB 050401: Optical afterglow candidate
  82. Swift-BAT detection of GRB 050401
  83. GRB 050401: Prompt XRT position
  84. Retraction of three Swift GRB triggers
  85. GRB050331: No Afterglow Detected
  86. Swift-BAT detection of GRB 050331b
  87. GRB 050331: Swift UVOT Source
  88. Swift-BAT detection of GRB 050331
  89. GRB 050331: Swift XRT Position
  90. Swift Data Publicly Available Starting April 5, 2005
  91. GRB050319: radio observation
  92. Konus-Wind observation of GRB 050326
  93. GRB050326: optical limit
  94. GRB 050326: Early observations with Swift-UVOT
  95. GRB 050326 XMM-Newton observation
  96. GRB 050326 : Planned XMM-Newton observation
  97. GRB 050326: Swift XRT Position
  98. GRB050326: optical limit 33min before GRB
  99. GRB 050326 BAT refined analysis
  100. GRB050326: delayed XRT observation

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