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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"

32532 results found.

  1. Swift UVOT Follow-up Observations of GRB 050509B
  2. GRB 050509B, Optical Observations
  3. GRB 050509B: Swift/XRT refined analysis
  4. GRB050509a: Swift UVOT observations
  5. GRB 050509b: Optical observations
  6. GRB 050509b: Precision Astrometry
  7. GRB 050509b: Possible Optical Counterpart
  8. GRB 050509A: Optical observations
  9. GRB 050509b: Optical Counterpart Candidate
  10. GRB050509b: Radio Observations
  11. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  12. GRB 050509b: optical observations
  13. GRB 050509b: Swift XRT Position
  14. GRB 050509B: ROTSE-III Optical Limits
  15. GRB 050509a: Swift XRT Position
  16. GRB 050505: Keck I-band Magnitude
  17. GRB 050505: early time observations
  18. GRB 050502a: Swift XRT Upper Limit
  19. GRB 050505, simultaneous optical observation
  20. GRB050505: Infrared observations
  21. GRB 050505: Further Swift UVOT observations.
  22. GRB050505: AAVSO observations
  23. GRB050416A : 1 GHz limit from GMRT
  24. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  25. GRB 050505 UVOT
  26. GRB050505: Optical Afterglow Candidate
  27. GRB 050505: Swift XRT Position
  28. GRB050505 Swift-BAT refined analysis
  29. GRB 050502a: Optical Observations
  30. GRB 050416b:Swift XRT afterglow upper limits
  31. GRB 050416b:Swift XRT afterglow upper limits
  32. Swift-BAT detection of GRB050505
  33. GRB 050504: Swift XRT position
  34. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  35. GRB050502b: Afterglow Confirmation
  36. GRB050502: P200 Observations (Correction)
  37. GRB050502: P200 Observations
  38. GRB 050504 : R band observation at Lulin observatory
  39. Swift UVOT observation of GRB 050504
  40. GRB 050504, R band Observations
  41. GRB050504: P60 Observations
  42. GRB 050502b, Optical observations
  43. GRB050502a: P60 Observations (Correction)
  44. GRB050502a: P60 Observations
  45. GRB 050502a: RBO Observations
  46. GRB 050502A: WSRT Radio Observations
  47. GRB050502A: Optical Observations
  48. GRB050502B Swift-BAT refined analysis
  49. GRB050502B: I band source in XRT error circle
  50. Swift UVOT refined analysis
  51. Retraction of Swift-BAT trigger 116145
  52. GRB 050502a : R band observation at Lulin observatory
  53. GRB 050502b : optical observation at Lulin observatory
  54. GRB 050502b: Swift XRT Position
  55. GRB050502B: Optical Limits from ANU 1m
  56. GRB 050502: INTEGRAL results
  57. GRB050502: ANU 1m optical Observations
  58. GRB 050502: Confirmed variability of the afterglow candidate +
  59. GRB 050502: PAIRITEL IR Observations
  60. GRB 050502: ROTSE-III Detection of Possible Counterpart
  61. Swift-BAT Trigger 115881 is not a real GRB
  62. Swift/BAT possible detection of a weak burst GRB050430
  63. GRB 050401: Rc observation
  64. GRB050416a: Radio Detection
  65. GRB 050422: Swift-UVOT observation
  66. GRB 050422: Swift-BAT refined analysis
  67. GRB 050422: Swift XRT Position
  68. GRB 050421: NIR observations
  69. GRB 050416: Optical/NIR observations
  70. GRB 050421: SLOTIS observations
  71. GRB 050421: Further Analysis of IR imaging
  72. GRB050421: Radio Observations
  73. GRB050421: Radio Observations
  74. GRB 050421: Swift-UVOT observation
  75. GRB 050421: IR Observations
  76. GRB 050421: Swift-BAT refined analysis
  77. GRB 050421: ROTSE-III Optical Limits
  78. GRB 050421: NIR observations re-examination
  79. GRB050421
  80. GRB 050421: early Swift XRT analysis results
  81. GRB 050421: NIR observations
  82. GRB050421: P60 Observations
  83. GRB 050421: BOOTES-2 simultaneous optical observations
  84. GRB 050421: Optical observations at the INT
  85. Swift Detection of GRB050421
  86. GRB 050416b: Tentative Swift XRT Position
  87. GRB 050315: potential host galaxy
  88. GRB050418: Null Optical Observations
  89. GRB 050412: Chandra observations
  90. GRB050416A, optical observations
  91. GRB 050418: Swift-BAT refined analysis
  92. GRB 050416: Mitsume optical observation
  93. GRB 050416 : optical observation at Xinglong observatory
  94. GRB 050416B: optical observations
  95. GRB 050416b: Swift-BAT refined analysis
  96. GRB 050416b: LCO observations
  97. GRB 050416b: LCO observations
  98. GRB050416B: IR observations
  99. GRB 050416: Swift/UVOT refined analysis
  100. GRB050412: Radio Observations

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