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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"

23403 results found.

  1. GRB 050505: SARA Observations
  2. GRB 050509B: Swift/XRT refined analysis
  3. GRB 050509b: Optical observations
  4. GRB 050509b: Possible Optical Counterpart
  5. GRB 050509A: Optical observations
  6. GRB050509b: Radio Observations
  7. GRB 050509B: ROTSE-III Optical Limits
  8. Swift Detection of GRB050509b: A short duration burst
  9. Swift Detection of the Burst GRB050509
  10. Swift-BAT detection of GRB 050507
  11. GRB 050502a: Swift XRT Upper Limit
  12. GRB 050505, simultaneous optical observation
  13. GRB 050505: Further Swift UVOT observations.
  14. GRB050505: AAVSO observations
  15. GRB050416A : 1 GHz limit from GMRT
  16. GRB050505: Optical Afterglow Candidate
  17. GRB050505 Swift-BAT refined analysis
  18. GRB 050416b:Swift XRT afterglow upper limits
  19. GRB 050416b:Swift XRT afterglow upper limits
  20. Swift-BAT detection of GRB050505
  21. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  22. GRB050502b: Afterglow Confirmation
  23. GRB050502: P200 Observations (Correction)
  24. GRB050502: P200 Observations
  25. Swift UVOT observation of GRB 050504
  26. GRB050504: P60 Observations
  27. GRB (?) 050504: IR Observations, Intriguing Source
  28. GRB 050502b, Optical observations
  29. GRB050502a: P60 Observations (Correction)
  30. GRB050502a: P60 Observations
  31. GRB 050502A: WSRT Radio Observations
  32. GRB050502A: Optical Observations
  33. GRB050502B Swift-BAT refined analysis
  34. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  35. Swift Detection of the Bright Burst GRB050502b
  36. GRB050502 - Optical Candidate from the Liverpool Telescope
  37. GRB 050502: ROTSE-III Detection of Possible Counterpart
  38. Swift/BAT possible detection of a weak burst GRB050430
  39. GRB050416a: Radio Detection
  40. GRB 050422: Swift-BAT refined analysis
  41. Swift Detection of GRB 050422
  42. GRB 050421: SLOTIS observations
  43. GRB 050421: Further Analysis of IR imaging
  44. GRB050421: Radio Observations
  45. GRB050421: Radio Observations
  46. GRB 050421: IR Observations
  47. GRB 050421: ROTSE-III Optical Limits
  48. GRB 050421: NIR observations re-examination
  49. GRB050421
  50. GRB 050421: early Swift XRT analysis results
  51. GRB 050421: NIR observations
  52. GRB050421: P60 Observations
  53. GRB 050421: BOOTES-2 simultaneous optical observations
  54. Swift Detection of GRB050421
  55. GRB 050416b: Tentative Swift XRT Position
  56. GRB 050315: potential host galaxy
  57. GRB050326: analysis of the XMM-Newton observation
  58. GRB050418: Null Optical Observations
  59. GRB050416A, optical observations
  60. GRB 050418: Swift-BAT refined analysis
  61. GRB 050416: Mitsume optical observation
  62. GRB 050416b: Swift-BAT refined analysis
  63. GRB050416B: IR observations
  64. GRB050412: Radio Observations
  65. GRB 050416: Swift/UVOT detection of afterglow emission
  66. GRB 050416: Swift-BAT refined analysis
  67. GRB 050416,optical observation
  68. GRB050416: P200 NIR Observations
  69. GRB 050416: Radio observations
  70. Swift BAT/XRT Detection of GRB 050416
  71. GRB 050412: Subaru observations
  72. GRB 050412: PROMPT VRcIc Observations
  73. GRB 050408: Kuiper 1.5m observations
  74. GRB 050412 : XingLong optical observation
  75. GRB 050412: Swift-BAT refined analysis
  76. GRB 050412: Early Optical/Ultraviolet Observations with
  77. GRB 050408: SDSS Field Calibration
  78. GRB 050412: Optical limit
  79. GRB050412: P60 Observations
  80. GRB050412: ROTSE-III Optical Limits
  81. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  82. GRB 050412: IR and Optical observations
  83. GRB 050412: IR Observations
  84. GRB050408: Radio Observations
  85. GRB 050401: Optical limit
  86. GRB 050408: Optical limit
  87. GRB050410: P60 Observations
  88. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  89. GRB 050410, optical observations
  90. GRB 050408: PROMPT VRcIc Observations
  91. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  92. GRB050410: Radio Observations
  93. GRB050410: MASTER optical observations
  94. GRB 050410: Early observations with Swift-UVOT
  95. GRB 050408: Inconsistency of host galaxy identification
  96. GRB 050408: Subaru Observations
  97. GRB 050408: WIDGET simultaneous optical observations
  98. GRB 050408: Properties of the Host Galaxy
  99. GRB050408: Radio Observations
  100. GRB 050408, optical observations

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