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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"

42185 results found.

  1. GRB100906A: MITSuME Okayama Optical Observation
  2. GRB 100906A: Ondrejov 65cm observations
  3. GRB 100906A: TLS Multicolor Observations
  4. GRB 100901A: TLS observations, SDSS calibration, decay slope
  5. GRB 100901A: ISON-NM optical observations
  6. GRB 100906A: Swift-BAT refined analysis
  7. GRB 100906A: UKIRT zYJHK Observation
  8. GRB 100906A: MASTER preliminary polarization prompt light curve
  9. GRB 100906A: Gemini-N/GMOS redshift
  10. GRB 100906A : Faulkes Telescope North optical observations
  11. GRB 100906A: MASTER early OT observations
  12. GRB 100906A: Swift detection of a burst with an optical afterglow
  13. GRB 100829A: MASTER optical observations
  14. GRB100905A: Optical upper limits at IAO
  15. GRB100905A: MITSuME Okayama optical upper limits
  16. GRB 100905A: Swift-XRT refined analysis.
  17. GRB 100905A: UKIRT zJHK Observation
  18. GRB 100901A: Possible WSRT Radio Detection
  19. GRB100905A: 1.5m OSN upper limit
  20. GRB 100905A: Enhanced Swift-XRT position
  21. GRB 100905A: Swift-BAT refined analysis
  22. GRB100904A: BOOTES-3 Upper Limit
  23. GRB 100905A: MASTER Prompt Optical Observations
  24. GRB 100905A: Swift detection of a burst
  25. Optical observations of GRB 100901A
  26. GRB10901A: Murikabushi telescope observation at 3 days after the burst
  27. GRB 100901A: Submm observations from SMA
  28. GRB 100902A: UKIRT JK Observation
  29. GRB 100901A: UKIRT zYJHK Observation
  30. GRB 100904A: Swift-BAT refined analysis
  31. GRB100902A: Optical upper limits at IAO
  32. GRB10901A: Optical observations at IAO
  33. Konus-Wind observation of GRB 100829A
  34. GRB 100904A: Swift detection of a burst
  35. GRB 100902A: Swift-BAT refined analysis
  36. GRB 100901A: optical observation at Mt.Terskol
  37. GRB 100901A: multicolor photometry at Mt.Terskol
  38. GRB 100901A: Lightbuckets Optical Observations
  39. GRB 100901A: HCT optical observations
  40. GRB 100902A: 1.5m OSN I-band Upper Limits
  41. Tentative redshift of GRB100902A from Swift-XRT data
  42. GRB 100902A: Swift XRT refined analysis
  43. GRB 100902A: Swift/UVOT Upper Limits
  44. GRB 100902A: optical observation at Mt.Terskol
  45. GRB 100901A: optical observation at Mt.Terskol
  46. GRB 100901A: Kanata Telescope observation of the optical afterglow
  47. GRB100901A: MITSuME Okayama Optical Observation at 1 day after the burst
  48. GRB 100902A: Enhanced Swift-XRT position
  49. GRB 100901A: TLS Observations: Break?
  50. GRB 100902A: MASTER Prompt Optical Observations
  51. GRB 100901A: ISON-NM optical observations
  52. GRB 100902A: MASTER Optical Early Limit
  53. GRB 100902A: Swift detection of a burst
  54. GRB 100901A: 1.5m OSN BVRI-band observations.
  55. GRB 100901A: ROTSE-III Detection
  56. GRB 100901A: MASTER optical flare at 420s discovery
  57. GRB 100901A: Vega telescope optical afterglow observation
  58. Swift/UVOT Observations of GRB100901A
  59. GRB 100901A : HCT optical observations
  60. GRB 100901A: SARA-N observations
  61. GRB 100901A: THO optical observations
  62. GRB100901A: MITSuME Okayama Optical Observation
  63. GRB 100901A: Swift-XRT Team refined analysis
  64. GRB 100901A - NOT optical observation
  65. GRB 100901A: Swift-BAT refined analysis
  66. GRB 100901A: optical observation at Mt.Terskol
  67. GRB 100901A: Enhanced Swift-XRT position
  68. GRB 100901A: optical observation at Mt.Terskol
  69. GRB 100901A: MASTER power low decay
  70. GRB 100901A: Gemini-N Redshift
  71. GRB 100901A: confirmation of the afterglow
  72. GRB 100901A: MASTER Optical Early Limits
  73. GRB 100901A: Faulkes Telescope North afterglow candidate
  74. GRB 100901A: Swift detection of a burst with an optical afterglow
  75. Konus-Wind observation of GRB 100826A
  76. GRB 100829.9: MASTER Optical Limits
  77. GRB100826A: Fermi-LAT Observations
  78. GRB 100823A: optical upper limit
  79. GRB 100814A: Maidanak optical observations
  80. GRB 100823A: optical observations
  81. GRB 100823A: MAXI/GSC detection
  82. GRB 100725B: Mondy optical upper limit
  83. GRB 100725B: Maidanak optical upper limit
  84. GRB 100823A: Swift/UVOT Evidence for Fading Afterglow Emission
  85. GRB100807A: R band observations
  86. GRB100823A : MOA optical observation
  87. GRB 100823A: Candidate IR afterglow
  88. GRB 100823A: Swift XRT refined analysis
  89. GRB 100823A: VLT/X-Shooter spectroscopy
  90. GRB 100823A - second epoch WHT observations
  91. GRB 100823A: TNG NIR observations
  92. GRB 100823: 1.5m OSN I-band observations
  93. GRB 100823A: Swift/UVOT Upper Limits
  94. GRB 100823A: WHT observations
  95. GRB 100823A: Swift-BAT refined analysis
  96. GRB 100823A: Enhanced Swift-XRT position
  97. GRB 100823A: Swift detection of a burst
  98. GRB 100814A: Suzaku WAM observation of the prompt emission
  99. GRB 100814A: ISON-NM optical observations
  100. IBAS Alert n. 6057 is not due to a GRB

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