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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"

16161 results found.

  1. GRB 091117: TNG optical observations
  2. GRB 091117: 2nd epoch of Magellan optical observations
  3. GRB 091117: Magellan optical observations
  4. GRB 091117: XRT source coincident with a DSS galaxy
  5. GRB 091109A: GROND and VLT observations
  6. GRB 091109b: Magellan Observations
  7. GRB 091109B: Optical limits from Watcher
  8. GRB 091109B: ROTSE-III Optical Limits
  9. GRB 091109: Swift/UVOT observations
  10. GRB 091109: Faulkes Telescope South observations
  11. GRB 091109: Swift detection of a burst with optical afterglow
  12. GRB 091104: Swift/UVOT Upper Limits
  13. GRB091102 : MOA optical upper limit
  14. GRB 091102: ROTSE-III Optical Limits
  15. GRB 091024: optical observations
  16. GRB 090926a, SMARTS optical/IR afterglow observations
  17. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  18. GRB 091029, SMARTS optical/IR afterglow observations
  19. GRB 091018, SMARTS optical/IR afterglow observations
  20. GRB091029: Swift/UVOT observations
  21. GRB 091029: Skynet/PROMPT Continued Observations of Fading
  22. GRB091024 optical observations
  23. GRB 091029: Gemini-South Redshift
  24. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  25. GRB 091029: Swift detection of a burst with an optical counterpart
  26. GRB 091024: Keck/LRIS Spectroscopy
  27. GRB 091024: YNAO-GMG observations
  28. GRB 091026: Swift/UVOT Upper Limits
  29. Konus-Wind and Konus-RF observations of GRB 091024
  30. GRB 091020 : Xinglong TNT upper limit
  31. GRB091024 Swift/UVOT Upper Limits
  32. GRB 091024: KAIT optical afterglow observations
  33. GRB 091024: Super-LOTIS early observations
  34. GRB091024: VRcIc Afterglow Observations
  35. GRB 091024: Swift-XRT team refined analysis
  36. GRB 091024: Xinglong TNT optical observation
  37. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  38. GRB 091024: GRAS004 optical observations
  39. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  40. GRB091020 Swift/UVOT observations
  41. GRB 091020: NOT spectroscopic redshift
  42. GRB 091020: MASTER optical transient polarimetry
  43. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  44. GRB 091020: Swift detection of a burst with an optical afterglow
  45. GRB 091018: ROTSE-III Detection of Optical Counterpart
  46. GRB 091018: Swift detection of a burst with optical afterglow
  47. GRB 091003: Possible Supernova Component
  48. GRB 091010: optical obsevation
  49. GRB 091015: RTT150 optical observations
  50. GRB 091010: optical afterglow candidate rejection
  51. GRB 091010: Enhanced XRT position
  52. GRB 091010 optical upper limits
  53. GRB 091010: Swift/UVOT Upper Limits
  54. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  55. GRB 090904A: afterglow confirmation
  56. GRB 090812: Skynet/PROMPT and GORT Observations
  57. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  58. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  59. GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
  60. GRB 090929B: Swift/UVOT Observations
  61. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  62. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  63. GRB 090927: VLT redshift
  64. GRB 090927: Zadko Telescope observations
  65. Swift/UVOT observations of GRB 090927
  66. GRB 090926A: Skynet/PROMPT Continued Observations
  67. GRB090926A: Swift/UVOT observations
  68. GRB 090926B: VLT spectroscopy
  69. GRB 090927: Swift/UVOT detection of an optical afterglow
  70. GRB 090926B: optical object in error circle
  71. GRB 090926B: NOT optical observation
  72. GRB 090926A: Swift/UVOT detection of an optical afterglow
  73. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  74. GRB 090912: optical observation
  75. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  76. GRB 090912: Swift/UVOT Upper Limits
  77. GRB 090912 optical upper limit
  78. GRB 090814A: Skynet/DSO & GORT Observations
  79. GRB 090904B: GROND detection of the optical afterglow
  80. GRB 090904B: MOA-II Optical observation
  81. GRB 090904A: NOT observations
  82. GRB 090902B: WSRT Radio Observation
  83. GRB090904B: REM observations
  84. GRB 090904A: ROTSE-III Optical Limits
  85. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  86. GRB 090902B: Swift/UVOT refined analysis
  87. GRB 090902B: GROND NIR Afterglow Observations
  88. GRB 090902B: Optical afterglow candidate
  89. GRB 090831B: MITSuME optical upper limits
  90. GRB 090831B, RIMOTS optical upper limits
  91. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  92. GRB 090820: MASTER-Net optical polarization observations
  93. GRB 090817: optical upper limit
  94. GRB 090813: I-band observations from 1.5m OSN telescope
  95. GRB 090817: Swift-XRT observations
  96. GRB 090814A: optical observations
  97. VLA radio non-detection of GRB 090812
  98. GRB 090813: CrAO optical obsevations
  99. GRB090814A: NOT optical follow-ups
  100. GRB 090814B: I-band observations from 1.23m CAHA telescope

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