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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"

20951 results found.

  1. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  2. GRB050502b: Afterglow Confirmation
  3. GRB050502: P200 Observations (Correction)
  4. GRB050502: P200 Observations
  5. GRB 050504 : R band observation at Lulin observatory
  6. GRB 050504, R band Observations
  7. GRB050504: Faulkes North optical robotic limit
  8. GRB 050502b, V band Observations
  9. GRB050504: P60 Observations
  10. GRB (?) 050504: IR Observations, Intriguing Source
  11. GRB 050502b, Optical observations
  12. GRB050502a: P60 Observations (Correction)
  13. GRB050502a: P60 Observations
  14. GRB 050502a: RBO Observations
  15. GRB 050502A: WSRT Radio Observations
  16. GRB050502A: Optical Observations
  17. GRB050502B Swift-BAT refined analysis
  18. GRB 050502b : optical observation at Lulin observatory
  19. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  20. Swift Detection of the Bright Burst GRB050502b
  21. GRB050502: ANU 1m optical Observations
  22. GRB 050502: Confirmed variability of the afterglow candidate +
  23. GRB 050502: PAIRITEL IR Observations
  24. GRB 050502: ROTSE-III Detection of Possible Counterpart
  25. Swift/BAT possible detection of a weak burst GRB050430
  26. GRB050416a: Radio Detection
  27. Swift Detection of GRB 050422
  28. GRB 050421: NIR observations
  29. GRB 050416: Optical/NIR observations
  30. GRB 050421: SLOTIS observations
  31. GRB 050421: Further Analysis of IR imaging
  32. GRB050421: Radio Observations
  33. GRB050421: Radio Observations
  34. GRB 050421: IR Observations
  35. GRB 050421: ROTSE-III Optical Limits
  36. GRB 050421: NIR observations re-examination
  37. GRB 050421: NIR observations
  38. GRB050421: P60 Observations
  39. GRB 050421: BOOTES-2 simultaneous optical observations
  40. GRB 050421: Optical observations at the INT
  41. Swift Detection of GRB050421
  42. GRB 050416b: Tentative Swift XRT Position
  43. GRB 050315: potential host galaxy
  44. GRB050418: Null Optical Observations
  45. GRB 050412: Chandra observations
  46. GRB050416A, optical observations
  47. GRB 050416 : optical observation at Xinglong observatory
  48. GRB 050416B: optical observations
  49. GRB 050416b: LCO observations
  50. GRB 050416b: LCO observations
  51. GRB050416B: IR observations
  52. GRB050412: Radio Observations
  53. GRB 050416: Swift/UVOT detection of afterglow emission
  54. GRB050416: Maidanak optical observations
  55. GRB 050416: ART observations
  56. GRB 050416: KAIT observations
  57. GRB050416: P200 NIR Observations
  58. GRB 050416: Radio observations
  59. GRB 050412: Subaru observations
  60. GRB 050408: RTT150 optical observations
  61. GRB 050412: PROMPT VRcIc Observations
  62. GRB 050408: Kuiper 1.5m observations
  63. GRB 050412: optical observations
  64. GRB 050408: refined XRT analysis, no jet break seen yet
  65. GRB 050412: ANU 2.3m observations
  66. GRB 050412: Early Optical/Ultraviolet Observations with
  67. GRB 050412: LCO Optical Observations
  68. GRB 050412: Optical observations
  69. GRB050412: P60 Observations
  70. GRB 050412: LCO optical observations
  71. GRB 050412: IR and Optical observations
  72. GRB 050412: IR Observations
  73. GRB050408: Radio Observations
  74. GRB050410: P60 Observations
  75. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  76. GRB 050410, optical observations
  77. GRB 050408: PROMPT VRcIc Observations
  78. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  79. GRB 050410 R band Optical Observations
  80. GRB 050410, optical observations
  81. GRB050410: Radio Observations
  82. GRB 050408: Swift XRT measurement of possible jet break
  83. GRB050410: MASTER optical observations
  84. GRB 050410: Early observations with Swift-UVOT
  85. Swift-BAT detection of GRB 050410
  86. GRB 050408: Subaru Observations
  87. GRB 050408: WIDGET simultaneous optical observations
  88. GRB 050408: SOAR UBVRc Observations
  89. GRB 050408: Properties of the Host Galaxy
  90. GRB 050408: Mercator Optical Observations
  91. GRB050408: Radio Observations
  92. GRB 050408, SMARTS optical/IR afterglow observations
  93. GRB 050408, optical observations
  94. GRB 050408 Optical Observations
  95. GRB 050408: Emission and absorption redshift
  96. GRB 050408: Mercator Optical Observations
  97. GRB 050408: Magellan astrometry and photometry
  98. GRB 050408: First Optical observations with TFOSC at the RTT150
  99. GRB 050408, optical observations
  100. GRB 050408 optical candidate

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