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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"

16159 results found.

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

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