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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"

27401 results found.

  1. Chandra observation of GRB 050509b
  2. GRB 050509b: RAPTOR deep, early limits.
  3. GRB050509B: Optical observations at the Very Large Telescope
  4. GRB 050509b: No Optical Variability in XRT Error Circle
  5. GRB 050509a: Swift-BAT refined analysis
  6. GRB 050509c: ROTSE-III Optical Limits
  7. GRB 050505, early TAROT observation
  8. GRB050509c: REM NIR and Optical observations
  9. GRB 050509b: Physical Properties of the Candidate Host galaxy
  10. GRB 050505: SARA Observations
  11. GRB 050509B, Optical Observations
  12. GRB 050509B: Swift/XRT refined analysis
  13. GRB 050509b: Optical observations
  14. GRB 050509A: Optical observations
  15. GRB050509b: Radio Observations
  16. GRB 050509b: PAIRITEL and WIYN Observations
  17. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  18. Swift Detection of GRB050509b: A short duration burst
  19. Swift Detection of the Burst GRB050509
  20. GRB 050505: early time observations
  21. GRB 050505, simultaneous optical observation
  22. GRB050505: AAVSO observations
  23. GRB050416A : 1 GHz limit from GMRT
  24. GRB050505: Optical Afterglow Candidate
  25. GRB050505 Swift-BAT refined analysis
  26. GRB 050416b:Swift XRT afterglow upper limits
  27. GRB 050416b:Swift XRT afterglow upper limits
  28. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  29. GRB050502b: Afterglow Confirmation
  30. GRB050502: P200 Observations (Correction)
  31. GRB050502: P200 Observations
  32. GRB 050504 : R band observation at Lulin observatory
  33. Swift UVOT observation of GRB 050504
  34. GRB 050504, R band Observations
  35. GRB 050502b, V band Observations
  36. GRB050504: P60 Observations
  37. GRB 050504: A long GRB detected with INTEGRAL
  38. GRB (?) 050504: IR Observations, Intriguing Source
  39. GRB 050502b, Optical observations
  40. GRB050502a: P60 Observations (Correction)
  41. GRB050502a: P60 Observations
  42. Renewal of SGR 1806-20 activity
  43. GRB050502B Swift-BAT refined analysis
  44. Swift UVOT refined analysis
  45. GRB 050502a : R band observation at Lulin observatory
  46. GRB 050502b : optical observation at Lulin observatory
  47. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  48. Swift Detection of the Bright Burst GRB050502b
  49. GRB 050502: INTEGRAL results
  50. GRB 050502: ROTSE-III Detection of Possible Counterpart
  51. Swift/BAT possible detection of a weak burst GRB050430
  52. GRB050416a: Radio Detection
  53. GRB 050422: Swift-UVOT observation
  54. GRB 050422: Swift-BAT refined analysis
  55. Swift Detection of GRB 050422
  56. GRB 050421: SLOTIS observations
  57. GRB 050421: Further Analysis of IR imaging
  58. GRB050421: Radio Observations
  59. GRB050421: Radio Observations
  60. GRB 050421: IR Observations
  61. GRB 050421: Swift-BAT refined analysis
  62. GRB050421
  63. GRB 050421: early Swift XRT analysis results
  64. GRB 050421: NIR observations
  65. GRB050421: P60 Observations
  66. GRB 050421: BOOTES-2 simultaneous optical observations
  67. GRB 050416b: Tentative Swift XRT Position
  68. GRB 050315: potential host galaxy
  69. GRB050326: analysis of the XMM-Newton observation
  70. GRB050418: Null Optical Observations
  71. GRB050416A, optical observations
  72. GRB 050418: Swift-BAT refined analysis
  73. GRB 050416: Mitsume optical observation
  74. GRB050416B: IR observations
  75. GRB050412: Radio Observations
  76. GRB 050416: Swift/UVOT detection of afterglow emission
  77. GRB050416: Refined Swift-XRT analysis
  78. GRB 050416,optical observation
  79. GRB050416: P200 NIR Observations
  80. GRB 050416: Radio observations
  81. Swift BAT/XRT Detection of GRB 050416
  82. GRB 050412: PROMPT VRcIc Observations
  83. GRB 050408: Kuiper 1.5m observations
  84. GRB 050412: early Swift XRT analysis results
  85. GRB 050412: Early Optical/Ultraviolet Observations with
  86. GRB 050408: SDSS Field Calibration
  87. GRB050412: P60 Observations
  88. GRB 050412: Swift XRT Position
  89. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  90. GRB 050412: IR and Optical observations
  91. GRB 050412: IR Observations
  92. GRB050408: Radio Observations
  93. GRB 050401: Optical limit
  94. GRB050410: P60 Observations
  95. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  96. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  97. GRB050410: Radio Observations
  98. GRB050410: MASTER optical observations
  99. GRB 050410: Early observations with Swift-UVOT
  100. Swift-BAT detection of GRB 050410

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