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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"

17851 results found.

  1. GRB 090831C: Swift detection of a burst
  2. GRB 090831B, RIMOTS optical upper limits
  3. GRB 090831B: Swift detection of a possible burst
  4. Konus-Wind observations of GRB 090827
  5. GRB 090827: Swift XRT and UVOT observations
  6. GRB 090817 - TLS Observations
  7. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  8. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  9. GRB 090820: MASTER-Net optical polarization observations
  10. GRB 090817: optical upper limit
  11. GRB 090817: Confirmation of the X-ray afterglow
  12. GRB 090817: Swift/UVOT Upper Limits
  13. GRB 090817: Swift-XRT observations
  14. GRB 090814A: optical observations
  15. VLA radio non-detection of GRB 090812
  16. GRB 090813: CrAO optical obsevations
  17. GRB090814A: NOT optical follow-ups
  18. GRB 090814B: Swift/UVOT Upper Limits
  19. GRB 090814B: Swift-XRT detection of a possible afterglow.
  20. GRB 090814A: Swift/UVOT Observations
  21. GRB 090814A, RIMOTS optical upper limits
  22. GRB090814A: VLT spectroscopy
  23. GRB 090814: Enhanced Swift-XRT position
  24. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  25. GRB 090814: Swift detection of a burst
  26. GRB 090813: Fermi GBM observation
  27. Konus-Wind observations of GRB090813
  28. GRB090813: Swift/UVOT upper limits
  29. GRB 090813: Enhanced Swift-XRT position
  30. GRB 090813: P60 Optical Afterglow Confirmation
  31. GRB 090813: Swift detection of a burst
  32. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  33. GRB 090812: RAPTOR detections during the burst
  34. GRB 090812, RIMOTS optical upper limits
  35. GRB090812: Swift/UVOT observations
  36. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  37. GRB 090812: Enhanced Swift-XRT position
  38. GRB 090812: P60 Confirmation of Optical Afterglow
  39. GRB 090812: Swift detection of a burst with an optical counterpart
  40. GRB 090809: Further NOT optical observations
  41. VLA radio upper limit on GRB 090809
  42. GRB 090809: WHT observations
  43. GRB 090809B: Fermi GBM detection
  44. GRB090809: Swift/UVOT observations
  45. GRB 090809: Enhanced Swift-XRT position
  46. GRB 090809: Swift-BAT refined analysis
  47. GRB 090809: afterglow confirmation at the NOT
  48. GRB 090809: Swift detection of a burst with a possible optical counterpart
  49. GRB 090807: MITSuME optical upper limit
  50. GRB 090807: Swift/UVOT Upper Limits
  51. GRB 090807: Enhanced Swift-XRT position
  52. GRB 090807, RIMOTS optical upper limits
  53. GRB 090807: Swift detection of a burst
  54. GRB 090726: optical observation
  55. Swift trigger 358760 is probably a noise event
  56. GRB 090727: GRT Optical Observation
  57. GRB 090726: GRT Optical Observation
  58. GRB 090727: Swift/UVOT Upper Limits
  59. GRB 090728: Swift/UVOT Upper Limits
  60. GRB 090728: Enhanced Swift-XRT position
  61. GRB 090728, RIMOTS optical upper limits
  62. GRB 090728: Swift detection of a burst
  63. GRB 090727: Enhanced Swift-XRT position
  64. GRB 090715B: Late-time Lick 3m observations
  65. GRB 090727: Swift detection of a burst
  66. GRB090726: Swift/UVOT observations
  67. GRB 090726: Enhanced Swift-XRT position
  68. GRB 090726: optical transient candidate
  69. Swift XRT and UVOT refned analysis of GRB 090720
  70. GRB 090709A: Swift XRT Timing Analysis
  71. GRB 090715B: VLA radio detection
  72. GRB 090720 Source found in ground processing of Swift-BAT data
  73. GRB 090718B: Fermi GBM detection
  74. GRB 090715B: further NOT optical observations
  75. GRB 090709A - CARMA mm Observations
  76. GRB 090715A: VLA observations
  77. GRB 090715B: Swift/UVOT followup observations
  78. GRB 090715B: Enhanced Swift-XRT position
  79. GRB 090715B: Observation of the optical afterglow
  80. GRB 090715B: NOT optical observations
  81. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  82. GRB 090715: Swift detection of a short hard burst
  83. GRB 090709A: Xinglong TNT optical upper limit
  84. VLA radio observations of GRB 090709A
  85. GRB 090621B: MTM-500 optical observations
  86. GRB 090709A: Swift UVOT upper limits
  87. GRB 090709A: WHT LIRIS observations
  88. GRB 090709A: P60 Observations
  89. GRB 090709A: NOT optical observations
  90. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  91. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  92. GRB 090709A, RIMOTS optical upper limits
  93. GRB 090709A: Enhanced Swift-XRT position
  94. GRB 090709A: Subaru NIR observation
  95. GRB 090709 : planned Suzaku-ToO observation
  96. GRB 090709: Faulkes Telescope North Upper Limits
  97. GRB 090709: PAIRITEL NIR Upper Limits
  98. GRB 090709: Swift detection of a bright burst
  99. GRB 090708: Early RAPTOR Optical Limits
  100. GRB 090708, Swift-BAT refined analysis

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