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

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