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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 100901A: Enhanced Swift-XRT position
  2. GRB 100901A: optical observation at Mt.Terskol
  3. GRB 100901A: MASTER power low decay
  4. GRB 100901A: Gemini-N Redshift
  5. GRB 100901A: MASTER: the OT brightenning
  6. GRB 100901A: confirmation of the afterglow
  7. GRB 100901A: MASTER Optical Early Limits
  8. GRB 100901A: Faulkes Telescope North afterglow candidate
  9. GRB 100901A: Swift detection of a burst with an optical afterglow
  10. Konus-Wind observation of GRB 100826A
  11. GRB 100829.9: MASTER Optical Limits
  12. IPN triangulation of GRB 100826A
  13. GRB100826A: Fermi-LAT Observations
  14. GRB 100823A: optical upper limit
  15. GRB 100814A: Maidanak optical observations
  16. GRB 100823A: optical observations
  17. GRB 100823A: MAXI/GSC detection
  18. GRB 100725B: Mondy optical upper limit
  19. GRB 100725B: Maidanak optical upper limit
  20. GRB 100823A: Swift/UVOT Evidence for Fading Afterglow Emission
  21. GRB100807A: R band observations
  22. GRB100823A : MOA optical observation
  23. GRB 100823A: Candidate IR afterglow
  24. GRB 100823A: Swift XRT refined analysis
  25. GRB 100823A: VLT/X-Shooter spectroscopy
  26. GRB 100823A - second epoch WHT observations
  27. GRB 100823A: TNG NIR observations
  28. GRB 100823: 1.5m OSN I-band observations
  29. GRB 100823A: Swift/UVOT Upper Limits
  30. GRB 100823A: WHT observations
  31. GRB 100823A: Swift-BAT refined analysis
  32. GRB 100823A: Enhanced Swift-XRT position
  33. GRB 100823A: Swift detection of a burst
  34. GRB 100814A: Suzaku WAM observation of the prompt emission
  35. GRB 100814A: ISON-NM optical observations
  36. IBAS Alert n. 6057 is not due to a GRB
  37. EVLA radio afterglow detection of GRB 100814A
  38. GRB 100814B: Fermi GBM detection
  39. GRB 100814A: optical observations
  40. GRB 100816A: Fermi GBM observation (correction to GCN 11124)
  41. Konus-Wind observation of GRB 100816A
  42. GRB100816A: MITSuME optical upper limits
  43. GRB 100816A: 10.4-m GTC redshift confirmation
  44. GRB 100816A: Fermi GBM observation
  45. GRB 100816A: VLT and Gemini-N revised redshift
  46. GRB 100814A : Liverpool Telescope Observations
  47. GRB 100814A: NOT optical observations
  48. GRB 100816A: NOT optical observations
  49. Konus-Wind observation of GRB 100814A
  50. GRB 100814A : Lulin optical observation
  51. GRB 100816A : Lulin r'-band observation
  52. GRB 100816A: Gemini-N spectroscopy
  53. GRB 100816A: Swift UVOT Observations
  54. GRB100816A Swift-XRT refined analysis
  55. GRB 100816A: Swift-BAT spectral lag results
  56. GRB 100816A: 1.23m CAHA optical observations
  57. GRB 100816A, Swift-BAT refined analysis
  58. GRB 100816A: Enhanced Swift-XRT position
  59. GRB 100816A: Gemini-N imaging
  60. GRB 100816A: CQUEAN riz-band Detection, Host Galaxy?
  61. GRB100814A - interesting UVOT lightcurve.
  62. GRB 100816A: TAROT Calern observatory optical detection
  63. GRB 100816A: MASTER Optical Limits
  64. GRB100816A: TNG optical afterglow confirmation.
  65. GRB 100816A: ROTSE-III Optical Limits
  66. GRB 100816A: Swift detection of a possibly short burst with optical afterglow
  67. Swift-BAT trigger 431756 is not a burst
  68. Swift/UVOT observations of GRB100814A - title correction to GCN 11097
  69. GRB 100814A: Fermi GBM observation
  70. GRB 100814A: Submm observations from APEX
  71. Swift/UVOT Observations of GRB100814A - a clearer table.
  72. GRB 100814A: Swift-XRT refined analysis
  73. Swift/UVOT observations of GRB100814A
  74. GRB 100814A, Swift-BAT refined analysis
  75. GRB 100814A: CQUEAN r- and i-band Observation
  76. GRB 100814A: Enhanced Swift-XRT position
  77. GRB 100814A: GROND Detection of the Optical/NIR Afterglow
  78. GRB 100814A: IAC80 R-band observations
  79. GRB100814A: Magellan Echellette Observations
  80. GRB 100814A: Swift UVOT observations of the optical afterglow
  81. GRB 100814A: Swift detection of a burst with an optical afterglow
  82. GRB 100814A: ROTSE-III Detection of Optical Counterpart
  83. Swift-BAT trigger 431582 likely is IGR J17464-2811
  84. GRB 100805A: the 4-th epoch of SAO RAS optical observations
  85. GRB 100805A: optical observation in CrAO (correction to the GCN 11077 and second epoch)
  86. GRB 100802A: further NOT observation
  87. GRB 100805A: Swift/UVOT Observations of a Possible Late-Time Brightening
  88. GRB 100807A: P200 Infrared Observations
  89. GRB 100805A: the 3-rd epoch of SAO RAS optical observations
  90. GRB100807A: optical observation in CrAO
  91. GRB 100805A: optical observation in CrAO
  92. GRB 100805A: 2-nd epoch of SAO RAS optical observations
  93. GRB100807A: MITSuME optical upper limits
  94. GRB 100807A: Swift XRT refined analysis
  95. GRB 100807A: P60 Optical Afterglow Discovery
  96. GRB 100807A: Swift/UVOT Upper Limits
  97. GRB 100805A: SAO RAS optical observations
  98. GRB 100807A: Enhanced Swift-XRT position
  99. GRB 100807A: Swift-BAT refined analysis
  100. GRB 100807A: ROTSE-III Optical Limits

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