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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. GRB090107B: Fermi GBM Detection
  2. GRB 090102: WSRT Radio Observations
  3. GRB 090107B: Swift XRT afterglow confirmation
  4. GRB 090107B: Swift/UVOT Observations
  5. GRB 090107B: Swift-XRT detection of possible afterglow
  6. GRB 090107B optical observations
  7. GRB 090107B: ROTSE-III Optical Limits
  8. GRB 090107B: a long GRB localized by INTEGRAL
  9. Fermi/GBM detection of GRB 081226A
  10. Fermi/GBM detection of GRB 081225
  11. GRB 090107: Swift-BAT refined analysis
  12. GRB 090107: Swift detection of a burst
  13. GRB 081231: Fermi GBM Detection
  14. GRB 090102: optical decay
  15. VLA radio upper limit on GRB 090102
  16. GRB 090102: GRT Optical Observation
  17. Swift triggered on the HMXB 1A 1118-61
  18. Konus-Wind observation of GRB 090102
  19. GRB 081229: Fermi GBM detection
  20. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  21. GRB 090102: P60 Imaging and P200 Spectroscopy
  22. GRB 090102 Observations from IAC80
  23. GRB 090102: GROND observations of the optical afterglow
  24. Swift UVOT observations of GRB 090102
  25. GRB 090102: Swift-BAT refined analysis
  26. GRB 090102: Swift burst of interest
  27. GRB 090102: Swift XRT refined analysis
  28. GRB 090102: NOT redshift
  29. GRB 090102: Enhanced Swift-XRT position
  30. GRB 090102: TAROT Calern observatory optical light curve
  31. GRB 090102: REM observations of a bright afterglow
  32. GRB 090102: Swift detection of a burst with an optical counterpart
  33. GRB 090102: TAROT Calern observatory optical observations
  34. GRB 081230: GROND confirmation of the afterglow
  35. GRB 081230, Swift-BAT refined analysis
  36. GRB081230: Swift-XRT refined analysis
  37. GRB 081230 Swift/UVOT Observations
  38. GRB 081230: Enhanced Swift-XRT position
  39. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  40. GRB 081230: ROTSE-III Detection of Optical Counterpart
  41. GRB 081230: Swift detection of a burst
  42. GRB 081228: GROND confirmation of the optical/NIR afterglow
  43. GRB 081226B: Fermi GBM observation
  44. GRB 081226C: Fermi GBM detection
  45. GRB 081228, Swift-BAT refined analysis
  46. VLA radio detection of GRB 081221
  47. GRB 081228: Swift/UVOT Upper Limits
  48. GRB 081228: Swift-XRT Team refined analysis
  49. GRB 081228: detection by GROND
  50. GRB 081228: Enhanced Swift-XRT position
  51. GRB 081228: TAROT Calern observatory optical observations
  52. GRB 081228: Swift detection of a burst
  53. VLA radio observation of GRB 081221
  54. GRB 081226B: Swift XRT and UVOT upper limits
  55. GRB 081224: Suzaku WAM observation of the prompt emission
  56. GRB 081226: Swift-XRT refined analysis
  57. GRB 081226A: Swift UVOT Upper Limits
  58. GRB 081226: Second epoch of Gemini-South imaging
  59. GRB 081226A: Swift-BAT refined analysis
  60. GRB 081226B: a short-hard GRB detected by INTEGRAL
  61. GRB 081226: Gemini-South spectrum of possible afterglow
  62. GRB 081226: Gemini-South imaging
  63. GRB 081226: GROND afterglow candidate
  64. GRB 081226: ROTSE-III Optical Limits
  65. GRB 081226: Swift detection of a possible short-hard burst
  66. GRB 080810: optical observations
  67. GRB 081211B: optical observations
  68. GRB081224: LAT retraction
  69. GRB 081224: Swift-XRT observation
  70. GRB 081222: MITSuME optical observation
  71. GRB 081224: Fermi GBM Detection & LAT Localization
  72. GRB 080810: optical observations
  73. Konus-Wind observation of GRB 081222
  74. GRB 081223: Fermi GBM detection
  75. GRB 081221: GROND observations
  76. GRB 081222: Gemini-N confirmation of redshift z=2.77
  77. GRB 081222:Optical afterglow observation
  78. VLA radio upper limit on GRB 081222
  79. GRB 081222: Fermi GBM observation
  80. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  81. GRB 081222: Gemini-South absorption redshift
  82. GRB081222: Swift/UVOT further observations
  83. GRB 081221: Probable host galaxy in Keck imaging
  84. GRB 081204C: Fermi GBM detection
  85. GRB 081222, Swift-BAT refined analysis
  86. GRB 081221, Swift-BAT refined analysis
  87. GRB081222 optical limit by "Pi of the Sky"
  88. Konus-Wind observation of very bright GRB 081215A
  89. GRB 081222: Swift XRT refined analysis
  90. GRB081221: Fermi GBM observation
  91. Swift/UVOT observations of GRB 081221
  92. IPN triangulation of bright GRB 081215A
  93. GRB 081221: Swift-XRT Refined Analysis
  94. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  95. GRB 081222: Faulkes Telescope South observations
  96. GRB 081221: Gemini-N nIR imaging
  97. GRB081222, optical observation
  98. GRB081222: Swift/UVOT detection of an optical afterglow
  99. GRB081203A: BTA observation
  100. Konus-Wind observation of GRB 081221

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