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

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