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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"

15685 results found.

  1. GRB 050421: Swift-UVOT observation
  2. GRB 050421: ROTSE-III Optical Limits
  3. GRB 050421: early Swift XRT analysis results
  4. GRB 050421: BOOTES-2 simultaneous optical observations
  5. GRB 050421: Optical observations at the INT
  6. Swift Detection of GRB050421
  7. GRB 050315: potential host galaxy
  8. GRB050326: analysis of the XMM-Newton observation
  9. GRB050418: Null Optical Observations
  10. GRB050416A, optical observations
  11. GRB 050416: Mitsume optical observation
  12. GRB 050416 : optical observation at Xinglong observatory
  13. GRB 050416B: optical observations
  14. GRB 050416: Swift/UVOT refined analysis
  15. GRB 050416: Swift/UVOT detection of afterglow emission
  16. GRB050416: Maidanak optical observations
  17. GRB 050416: ART observations
  18. GRB 050416,optical observation
  19. GRB 050416: Swift XRT Position
  20. GRB 050408: RTT150 optical observations
  21. GRB050408: optical observation
  22. GRB 050412: optical limit
  23. GRB 050412: optical observations
  24. GRB 050412 : XingLong optical observation
  25. GRB 050412: Early Optical/Ultraviolet Observations with
  26. GRB 050412: Optical limit
  27. GRB 050412: LCO Optical Observations
  28. GRB 050412: Optical observations
  29. GRB050412: optical limit before and during GRB
  30. GRB 050412: LCO optical observations
  31. GRB050412: ROTSE-III Optical Limits
  32. GRB 050412: IR and Optical observations
  33. GRB050408: Radio Observations
  34. GRB 050401: Optical limit
  35. GRB 050408: Optical limit
  36. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  37. GRB 050410, optical observations
  38. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  39. GRB 050410 R band Optical Observations
  40. GRB 050410, optical observations
  41. GRB050410: MASTER optical observations
  42. GRB 050410: Early observations with Swift-UVOT
  43. Swift-BAT detection of GRB 050410
  44. GRB 050408: WIDGET simultaneous optical observations
  45. GRB 050408: SOAR UBVRc Observations
  46. GRB 050408: Properties of the Host Galaxy
  47. GRB 050408: Mercator Optical Observations
  48. GRB050408: Radio Observations
  49. GRB 050408: Swift XRT analysis
  50. GRB 050408, SMARTS optical/IR afterglow observations
  51. GRB 050408: Optical limit at 20 min after the burst
  52. GRB 050408, optical observations
  53. GRB050408: REM NIR and Optical observation
  54. GRB 050408: Moderate-resolution Gemini Spectroscopy
  55. GRB 050408,optical observation
  56. GRB 050408 Optical Observations
  57. GRB 050408: Emission and absorption redshift
  58. GRB 050408: Mercator Optical Observations
  59. GRB 050408: First Optical observations with TFOSC at the RTT150
  60. GRB 050408: steepening of the optical decay
  61. GRB 050408: Optical afterglow confirmed
  62. GRB 050408, optical observations
  63. GRB 050408 optical candidate
  64. GRB 050408: ROTSE-III Optical Limits
  65. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  66. GRB050408: MASTER optical observations
  67. GRB050401: Radio Detection
  68. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  69. GRB 050406: Magellan optical observations
  70. GRB 050406: Early observations with Swift-UVOT
  71. Swift-BAT detection of GRB 050406
  72. GRB050401: Radio observation at 610 MHz with GMRT
  73. GRB 050401: VLT spectroscopic redshift
  74. GRB 050401 Optical Observations
  75. GRB050401: Maidanak optical observation
  76. GRB 050401 BAT refined analysis
  77. GRB050401: TNG R-band observation
  78. GRB 050402: Early observations with Swift-UVOT
  79. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  80. GRB 050401: Optical afterglow confirmed
  81. GRB 050401: Optical afterglow candidate
  82. GRB050331: No Afterglow Detected
  83. GRB 050331: Swift UVOT Source
  84. GRB050326: optical limit
  85. GRB 050326: Early observations with Swift-UVOT
  86. GRB050326: optical limit 33min before GRB
  87. GRB050319, optical observations
  88. GRB050319, color indices
  89. GRB050319: optical observation, March 20-22
  90. GRB050319: RTT150 Optical Observations
  91. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  92. GRB 050318: Swift-BAT refined analysis
  93. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  94. GRB050319: VLA Observations
  95. GRB050319: radio observation
  96. GRB 050319 R band observations
  97. GRB 050319: Swift-UVOT detection of the afterglow
  98. GRB050319: Radio Observations
  99. GRB 050319: NIR afterglow candidate
  100. GRB 050319:Near IR afterglow

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