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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"

15985 results found.

  1. GRB050504: Faulkes North optical robotic limit
  2. GRB 050504: A long GRB detected with INTEGRAL
  3. GRB (?) 050504: IR Observations, Intriguing Source
  4. GRB 050502b, Optical observations
  5. GRB 050502A: WSRT Radio Observations
  6. GRB050502A: Optical Observations
  7. GRB 050502a : R band observation at Lulin observatory
  8. GRB 050502b : optical observation at Lulin observatory
  9. GRB050502B: Optical Limits from ANU 1m
  10. Swift Detection of the Bright Burst GRB050502b
  11. GRB050502: ANU 1m optical Observations
  12. GRB 050502: Confirmed variability of the afterglow candidate +
  13. GRB050502 - Correction on the Optical Candidate from the Liverpool
  14. GRB050502 - Optical Candidate from the Liverpool Telescope
  15. Swift/BAT possible detection of a weak burst GRB050430
  16. GRB 050401: Rc observation
  17. GRB050416a: Radio Detection
  18. GRB 050422: Swift-UVOT observation
  19. Swift Detection of GRB 050422
  20. GRB 050421: NIR observations
  21. GRB 050416: Optical/NIR observations
  22. GRB 050421: Swift-UVOT observation
  23. GRB 050421: ROTSE-III Optical Limits
  24. GRB 050421: early Swift XRT analysis results
  25. GRB 050421: BOOTES-2 simultaneous optical observations
  26. GRB 050421: Optical observations at the INT
  27. Swift Detection of GRB050421
  28. GRB 050315: potential host galaxy
  29. GRB050326: analysis of the XMM-Newton observation
  30. GRB050418: Null Optical Observations
  31. GRB050416A, optical observations
  32. GRB 050416: Mitsume optical observation
  33. GRB 050416 : optical observation at Xinglong observatory
  34. GRB 050416B: optical observations
  35. GRB 050416: Swift/UVOT refined analysis
  36. GRB 050416: Swift/UVOT detection of afterglow emission
  37. GRB050416: Maidanak optical observations
  38. GRB 050416: ART observations
  39. GRB 050416,optical observation
  40. GRB 050416: Swift XRT Position
  41. GRB 050408: RTT150 optical observations
  42. GRB050408: optical observation
  43. GRB 050412: optical limit
  44. GRB 050412: optical observations
  45. GRB 050412 : XingLong optical observation
  46. GRB 050412: Early Optical/Ultraviolet Observations with
  47. GRB 050412: Optical limit
  48. GRB 050412: LCO Optical Observations
  49. GRB 050412: Optical observations
  50. GRB050412: optical limit before and during GRB
  51. GRB 050412: LCO optical observations
  52. GRB050412: ROTSE-III Optical Limits
  53. GRB 050412: IR and Optical observations
  54. GRB050408: Radio Observations
  55. GRB 050401: Optical limit
  56. GRB 050408: Optical limit
  57. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  58. GRB 050410, optical observations
  59. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  60. GRB 050410 R band Optical Observations
  61. GRB 050410, optical observations
  62. GRB050410: MASTER optical observations
  63. GRB 050410: Early observations with Swift-UVOT
  64. GRB 050408: WIDGET simultaneous optical observations
  65. GRB 050408: SOAR UBVRc Observations
  66. GRB 050408: Properties of the Host Galaxy
  67. GRB 050408: Mercator Optical Observations
  68. GRB050408: Radio Observations
  69. GRB 050408: Swift XRT analysis
  70. GRB 050408, SMARTS optical/IR afterglow observations
  71. GRB 050408: Optical limit at 20 min after the burst
  72. GRB 050408, optical observations
  73. GRB050408: REM NIR and Optical observation
  74. GRB 050408: Moderate-resolution Gemini Spectroscopy
  75. GRB 050408,optical observation
  76. GRB 050408 Optical Observations
  77. GRB 050408: Emission and absorption redshift
  78. GRB 050408: Mercator Optical Observations
  79. GRB 050408: First Optical observations with TFOSC at the RTT150
  80. GRB 050408: steepening of the optical decay
  81. GRB 050408: Optical afterglow confirmed
  82. GRB 050408, optical observations
  83. GRB 050408 optical candidate
  84. GRB 050408: ROTSE-III Optical Limits
  85. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  86. GRB050408: MASTER optical observations
  87. GRB050401: Radio Detection
  88. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  89. GRB 050406: Magellan optical observations
  90. GRB 050406: Early observations with Swift-UVOT
  91. Swift-BAT detection of GRB 050406
  92. GRB050401: Radio observation at 610 MHz with GMRT
  93. GRB 050401: VLT spectroscopic redshift
  94. GRB 050401 Optical Observations
  95. GRB050401: Maidanak optical observation
  96. GRB 050401 BAT refined analysis
  97. GRB050401: TNG R-band observation
  98. GRB 050402: Early observations with Swift-UVOT
  99. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  100. GRB 050401: Optical afterglow confirmed

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