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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"
  1. GRB 100902A: MASTER Prompt Optical Observations
  2. GRB 100901A: ISON-NM optical observations
  3. GRB 100902A: Faulkes Telescope South observations
  4. GRB 100902A: MASTER Optical Early Limit
  5. GRB 100902A: Swift detection of a burst
  6. GRB 100901A: 1.5m OSN BVRI-band observations.
  7. GRB 100901A: ROTSE-III Detection
  8. GRB 100901A: MASTER optical flare at 420s discovery
  9. GRB 100901A: Vega telescope optical afterglow observation
  10. Swift/UVOT Observations of GRB100901A
  11. GRB 100901A : HCT optical observations
  12. GRB 100901A: SARA-N observations
  13. GRB 100901A: THO optical observations
  14. GRB100901A: MITSuME Okayama Optical Observation
  15. GRB 100901A: Swift-XRT Team refined analysis
  16. GRB 100901A - NOT optical observation
  17. GRB 100901A: Swift-BAT refined analysis
  18. GRB 100901A: optical observation at Mt.Terskol
  19. GRB 100901A: Enhanced Swift-XRT position
  20. GRB 100901A: optical observation at Mt.Terskol
  21. GRB 100901A: MASTER power low decay
  22. GRB 100901A: Gemini-N Redshift
  23. GRB 100901A: MASTER: the OT brightenning
  24. GRB 100901A: confirmation of the afterglow
  25. GRB 100901A: MASTER Optical Early Limits
  26. GRB 100901A: Faulkes Telescope North afterglow candidate
  27. GRB 100901A: Swift detection of a burst with an optical afterglow
  28. Konus-Wind observation of GRB 100826A
  29. GRB 100829.9: MASTER Optical Limits
  30. IPN triangulation of GRB 100826A
  31. GRB100826A: Fermi-LAT Observations
  32. GRB 100823A: optical upper limit
  33. GRB 100814A: Maidanak optical observations
  34. GRB 100823A: optical observations
  35. GRB 100823A: MAXI/GSC detection
  36. GRB 100725B: Mondy optical upper limit
  37. GRB 100725B: Maidanak optical upper limit
  38. GRB 100823A: Swift/UVOT Evidence for Fading Afterglow Emission
  39. GRB100807A: R band observations
  40. GRB100823A : MOA optical observation
  41. GRB 100823A: Candidate IR afterglow
  42. GRB 100823A: Swift XRT refined analysis
  43. GRB 100823A: VLT/X-Shooter spectroscopy
  44. GRB 100823A - second epoch WHT observations
  45. GRB 100823A: TNG NIR observations
  46. GRB 100823: 1.5m OSN I-band observations
  47. GRB 100823A: Swift/UVOT Upper Limits
  48. GRB 100823A: WHT observations
  49. GRB 100823A: Swift-BAT refined analysis
  50. GRB 100823A: Enhanced Swift-XRT position
  51. GRB 100823A: Swift detection of a burst
  52. GRB 100814A: Suzaku WAM observation of the prompt emission
  53. GRB 100814A: ISON-NM optical observations
  54. IBAS Alert n. 6057 is not due to a GRB
  55. EVLA radio afterglow detection of GRB 100814A
  56. GRB 100814B: Fermi GBM detection
  57. GRB 100814A: optical observations
  58. GRB 100816A: Fermi GBM observation (correction to GCN 11124)
  59. Konus-Wind observation of GRB 100816A
  60. GRB100816A: MITSuME optical upper limits
  61. GRB 100816A: 10.4-m GTC redshift confirmation
  62. GRB 100816A: Fermi GBM observation
  63. GRB 100816A: VLT and Gemini-N revised redshift
  64. GRB 100814A : Liverpool Telescope Observations
  65. GRB 100814A: NOT optical observations
  66. GRB 100816A: NOT optical observations
  67. Konus-Wind observation of GRB 100814A
  68. GRB 100814A : Lulin optical observation
  69. GRB 100816A : Lulin r'-band observation
  70. GRB 100816A: Gemini-N spectroscopy
  71. GRB 100816A: Swift UVOT Observations
  72. GRB100816A Swift-XRT refined analysis
  73. GRB 100816A: Swift-BAT spectral lag results
  74. GRB 100816A: 1.23m CAHA optical observations
  75. GRB 100816A, Swift-BAT refined analysis
  76. GRB 100816A: Enhanced Swift-XRT position
  77. GRB 100816A: Gemini-N imaging
  78. GRB 100816A: CQUEAN riz-band Detection, Host Galaxy?
  79. GRB100814A - interesting UVOT lightcurve.
  80. GRB 100816A: TAROT Calern observatory optical detection
  81. GRB 100816A: MASTER Optical Limits
  82. GRB100816A: TNG optical afterglow confirmation.
  83. GRB 100816A: ROTSE-III Optical Limits
  84. GRB 100816A: Swift detection of a possibly short burst with optical afterglow
  85. Swift-BAT trigger 431756 is not a burst
  86. Swift/UVOT observations of GRB100814A - title correction to GCN 11097
  87. GRB 100814A: Fermi GBM observation
  88. GRB 100814A: Submm observations from APEX
  89. Swift/UVOT Observations of GRB100814A - a clearer table.
  90. GRB 100814A: Swift-XRT refined analysis
  91. Swift/UVOT observations of GRB100814A
  92. GRB 100814A, Swift-BAT refined analysis
  93. GRB 100814A: CQUEAN r- and i-band Observation
  94. GRB 100814A: Enhanced Swift-XRT position
  95. GRB 100814A: GROND Detection of the Optical/NIR Afterglow
  96. GRB 100814A: IAC80 R-band observations
  97. GRB100814A: Magellan Echellette Observations
  98. GRB 100814A: Swift UVOT observations of the optical afterglow
  99. GRB 100814A: Swift detection of a burst with an optical afterglow
  100. GRB 100814A: ROTSE-III Detection of Optical Counterpart

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