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

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