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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"
  1. GRB050509B: Optical observations at the Very Large Telescope
  2. GRB 050509b: No Optical Variability in XRT Error Circle
  3. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  4. GRB 050509a: Swift-BAT refined analysis
  5. GRB 050509c: ROTSE-III Optical Limits
  6. GRB 050509B: WSRT Radio Observations
  7. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  8. GRB 050505, early TAROT observation
  9. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  10. GRB 050509b: Further Analysis of Keck LRIS Images
  11. GRB050509c: REM NIR and Optical observations
  12. GRB 050509b: Physical Properties of the Candidate Host galaxy
  13. GRB 050505: SARA Observations
  14. Swift UVOT Follow-up Observations of GRB 050509B
  15. GRB 050509B, Optical Observations
  16. GRB 050509B: Swift/XRT refined analysis
  17. GRB050509a: Swift UVOT observations
  18. GRB 050509b: Optical observations
  19. GRB 050509b: Precision Astrometry
  20. GRB 050509b: Possible Optical Counterpart
  21. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  22. GRB 050509A: Optical observations
  23. GRB 050509b: Optical Counterpart Candidate
  24. GRB050509b: Radio Observations
  25. GRB 050509b: PAIRITEL and WIYN Observations
  26. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  27. GRB 050509b: optical observations
  28. GRB 050509b: Swift XRT Position
  29. GRB 050509B: ROTSE-III Optical Limits
  30. Swift Detection of GRB050509b: A short duration burst
  31. GRB 050509a: Swift XRT Position
  32. Swift Detection of the Burst GRB050509
  33. Swift-BAT detection of GRB 050507
  34. GRB 050505: Keck I-band Magnitude
  35. GRB 050505: early time observations
  36. GRB 050505 - Faulkes Telescope North observations
  37. GRB 050502a: Swift XRT Upper Limit
  38. GRB 050505, simultaneous optical observation
  39. GRB050505: Infrared observations
  40. GRB 050505: Further Swift UVOT observations.
  41. GRB050505: AAVSO observations
  42. GRB050416A : 1 GHz limit from GMRT
  43. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  44. GRB 050505 UVOT
  45. GRB050505: Optical Afterglow Candidate
  46. GRB 050505: Swift XRT Position
  47. GRB050505 Swift-BAT refined analysis
  48. GRB 050502a: Optical Observations
  49. GRB 050416b:Swift XRT afterglow upper limits
  50. GRB 050416b:Swift XRT afterglow upper limits
  51. Swift-BAT detection of GRB050505
  52. GRB 050504: Swift XRT position
  53. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  54. GRB050502b: Afterglow Confirmation
  55. GRB050502: P200 Observations (Correction)
  56. GRB050502: P200 Observations
  57. GRB 050504 : R band observation at Lulin observatory
  58. Swift UVOT observation of GRB 050504
  59. GRB 050504, R band Observations
  60. GRB050504: Faulkes North optical robotic limit
  61. GRB 050502b, V band Observations
  62. GRB050504: P60 Observations
  63. GRB 050504: A long GRB detected with INTEGRAL
  64. GRB (?) 050504: IR Observations, Intriguing Source
  65. GRB 050502b, Optical observations
  66. GRB050502a: P60 Observations (Correction)
  67. GRB050502a: P60 Observations
  68. Renewal of SGR 1806-20 activity
  69. GRB 050502a: RBO Observations
  70. GRB 050502A: WSRT Radio Observations
  71. GRB050502A: Optical Observations
  72. GRB050502B Swift-BAT refined analysis
  73. GRB050502B: I band source in XRT error circle
  74. Swift UVOT refined analysis
  75. Retraction of Swift-BAT trigger 116145
  76. GRB 050502a : R band observation at Lulin observatory
  77. GRB 050502b : optical observation at Lulin observatory
  78. GRB 050502b: Swift XRT Position
  79. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  80. GRB050502B: Optical Limits from ANU 1m
  81. Swift Detection of the Bright Burst GRB050502b
  82. GRB 050502: INTEGRAL results
  83. GRB050502: ANU 1m optical Observations
  84. GRB 050502: Confirmed variability of the afterglow candidate +
  85. GRB 050502: PAIRITEL IR Observations
  86. GRB050502 - Correction on the Optical Candidate from the Liverpool
  87. GRB050502 - Optical Candidate from the Liverpool Telescope
  88. GRB 050502 - A long GRB detected with INTEGRAL
  89. GRB 050502: ROTSE-III Detection of Possible Counterpart
  90. Swift-BAT Trigger 115881 is not a real GRB
  91. Swift/BAT possible detection of a weak burst GRB050430
  92. GRB 050401: Rc observation
  93. GRB050416a: Radio Detection
  94. GRB 050422: Swift-UVOT observation
  95. GRB 050422: Swift-BAT refined analysis
  96. GRB 050422: Swift XRT Position
  97. Swift Detection of GRB 050422
  98. GRB 050421: NIR observations
  99. GRB 050416: Optical/NIR observations
  100. GRB 050421: SLOTIS observations

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