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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"

15999 results found.

  1. GRB 090926B: VLT spectroscopy
  2. GRB 090927: Swift/UVOT detection of an optical afterglow
  3. GRB 090926B: optical object in error circle
  4. GRB 090926B: NOT optical observation
  5. GRB 090926A: Swift/UVOT detection of an optical afterglow
  6. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  7. GRB 090912: optical observation
  8. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  9. GRB 090912: Swift/UVOT Upper Limits
  10. GRB 090912 optical upper limit
  11. GRB 090904B: GROND detection of the optical afterglow
  12. GRB 090904B: MOA-II Optical observation
  13. GRB 090904A: NOT observations
  14. GRB 090902B: WSRT Radio Observation
  15. GRB 090904A: ROTSE-III Optical Limits
  16. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  17. GRB 090902B: Swift/UVOT refined analysis
  18. GRB 090902B: GROND NIR Afterglow Observations
  19. GRB 090902B: Optical afterglow candidate
  20. GRB 090831B: MITSuME optical upper limits
  21. GRB 090831B, RIMOTS optical upper limits
  22. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  23. GRB 090820: MASTER-Net optical polarization observations
  24. GRB 090817: optical upper limit
  25. GRB 090813: I-band observations from 1.5m OSN telescope
  26. GRB 090817: Swift-XRT observations
  27. GRB 090814A: optical observations
  28. VLA radio non-detection of GRB 090812
  29. GRB 090813: CrAO optical obsevations
  30. GRB090814A: NOT optical follow-ups
  31. GRB 090814B: I-band observations from 1.23m CAHA telescope
  32. GRB 090814B: Swift/UVOT Upper Limits
  33. GRB 090814A: Swift/UVOT Observations
  34. GRB 090814A, RIMOTS optical upper limits
  35. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  36. GRB090813: Swift/UVOT upper limits
  37. GRB 090813: Liverpool Telescope afterglow confirmation
  38. GRB 090813: P60 Optical Afterglow Confirmation
  39. GRB 090813: optical candidate from 1.23m CAHA telescope
  40. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  41. GRB 090812: RAPTOR detections during the burst
  42. GRB 090812: Swift XRT refined analysis
  43. GRB 090812, RIMOTS optical upper limits
  44. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  45. GRB 090812: Liverpool Telescope afterglow confirmation
  46. GRB 090812: P60 Confirmation of Optical Afterglow
  47. GRB 090812: Swift detection of a burst with an optical counterpart
  48. GRB 090809: Further NOT optical observations
  49. VLA radio upper limit on GRB 090809
  50. GRB 090809: afterglow confirmation at the NOT
  51. GRB 090809: Swift detection of a burst with a possible optical counterpart
  52. GRB 090807: MITSuME optical upper limit
  53. GRB 090807: Swift/UVOT Upper Limits
  54. GRB 090807, RIMOTS optical upper limits
  55. GRB 090726: optical observation
  56. GRB 090727: GRT Optical Observation
  57. GRB 090727: optical observations
  58. GRB 090726: GRT Optical Observation
  59. GRB 090728: Swift/UVOT Upper Limits
  60. GRB 090727: I-band observations from 1.23m CAHA
  61. GRB 090728, RIMOTS optical upper limits
  62. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  63. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  64. GRB 090715B: Late-time Lick 3m observations
  65. GRB 090726: D50 optical observations
  66. GRB090726: 6-meter telescope redshift
  67. GRB 090726: optical transient candidate
  68. GRB 090720: Gemini-North Imaging and Optical Afterglow
  69. GRB 090715B: further NOT optical observations
  70. GRB 090709A - CARMA mm Observations
  71. GRB 090715B: Lick observations
  72. GRB 090715B: MASTER optical limit
  73. GRB 090715B: Swift/UVOT followup observations
  74. GRB 090715B: break in the optical afterglow decay
  75. GRB 090715B: Observation of the optical afterglow
  76. GRB 090715B: NOT optical observations
  77. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  78. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  79. GRB 090715A: ROTSE-III Optical Limits
  80. GRB090713 optical limit by "Pi of the Sky"
  81. GRB 090709A: Xinglong TNT optical upper limit
  82. GRB 090621B: MTM-500 optical observations
  83. GRB 090709A: deep optical observation with the 10.4m GTC
  84. GRB 090709A: NOT optical observations
  85. GRB 090709A, RIMOTS optical upper limits
  86. GRB 090709A: Subaru NIR observation
  87. GRB 090709: ROTSE-III Optical Limits
  88. GRB 090708: Early RAPTOR Optical Limits
  89. GRB 090708: ROTSE-III Optical Limits
  90. XRF 090702 : RTT150 optical observations
  91. GRB 090618: Mondy optical observations
  92. GRB 090529: CrAO optical upper limit
  93. GRB 090529: MTM-500 optical observations
  94. GRB 090529: Mt.Terskol optical observations
  95. GRB 090313: optical observations
  96. XRF 090702: VLT imaging
  97. GRB 090404: Deep optical imaging and possible host association (correction)
  98. GRB 090404: Deep optical imaging and possible host association
  99. GRB 090618: RTT150 optical observations
  100. GRB080628: SAO RAS optical observations

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