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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"

27401 results found.

  1. GRB 090113: Swift UVOT upper limits
  2. GRB 090113: GROND Upper Limits
  3. GRB 090113: Swift-XRT refined analysis
  4. GRB 090113: Observations from NOT
  5. GRB 090113: Enhanced Swift-XRT position
  6. GRB 090113: Swift-BAT refined analysis
  7. GRB 090113: ROTSE-III Optical Limits
  8. GRB 090112B: Fermi GBM Detection
  9. GRB 090113: Swift detection of a burst
  10. GRB 090112: Fermi GBM detection
  11. GRB 090109: Fermi GBM detection
  12. GRB 090108B: Fermi GBM detection
  13. GRB 090111, Swift-BAT refined analysis
  14. GRB 090111: Swift UVOT Upper Limits
  15. GRB 090108: Fermi GBM Detection
  16. GRB 090111: Swift-XRT refined analysis
  17. GRB 090111: Enhanced Swift-XRT position
  18. GRB 090111: Swift detection of a burst
  19. GRB 090107B: Suzaku WAM observation of the prompt emission
  20. GRB090107B: Fermi GBM Detection
  21. GRB 090107B: Swift XRT afterglow confirmation
  22. GRB 090107B: Swift/UVOT Observations
  23. GRB 090107B: Swift-XRT detection of possible afterglow
  24. GRB 090107B: a long GRB localized by INTEGRAL
  25. Fermi/GBM detection of GRB 081226A
  26. Fermi/GBM detection of GRB 081225
  27. GRB 090107: Swift-BAT refined analysis
  28. GRB 081231: Fermi GBM Detection
  29. VLA radio upper limit on GRB 090102
  30. GRB 090102: GRT Optical Observation
  31. Swift triggered on the HMXB 1A 1118-61
  32. GRB 081229: Fermi GBM detection
  33. GRB 090102: P60 Imaging and P200 Spectroscopy
  34. GRB 090102 Observations from IAC80
  35. GRB 090102: GROND observations of the optical afterglow
  36. GRB 090102: Swift-BAT refined analysis
  37. GRB 090102: Swift XRT refined analysis
  38. GRB 090102: NOT redshift
  39. GRB 090102: Enhanced Swift-XRT position
  40. GRB 090102: REM observations of a bright afterglow
  41. GRB 090102: Swift detection of a burst with an optical counterpart
  42. GRB 090102: TAROT Calern observatory optical observations
  43. GRB 081230: GROND confirmation of the afterglow
  44. GRB 081230, Swift-BAT refined analysis
  45. GRB081230: Swift-XRT refined analysis
  46. GRB 081230 Swift/UVOT Observations
  47. GRB 081230: Enhanced Swift-XRT position
  48. GRB 081230: ROTSE-III Detection of Optical Counterpart
  49. GRB 081230: Swift detection of a burst
  50. GRB 081226C: Fermi GBM detection
  51. GRB 081228, Swift-BAT refined analysis
  52. VLA radio detection of GRB 081221
  53. GRB 081228: Swift/UVOT Upper Limits
  54. GRB 081228: Swift-XRT Team refined analysis
  55. GRB 081228: detection by GROND
  56. GRB 081228: Enhanced Swift-XRT position
  57. GRB 081228: TAROT Calern observatory optical observations
  58. GRB 081228: Swift detection of a burst
  59. VLA radio observation of GRB 081221
  60. GRB 081226B: Swift XRT and UVOT upper limits
  61. GRB 081224: Suzaku WAM observation of the prompt emission
  62. GRB 081226: Swift-XRT refined analysis
  63. GRB 081226A: Swift UVOT Upper Limits
  64. GRB 081226A: Swift-BAT refined analysis
  65. GRB 081226: GROND afterglow candidate
  66. GRB 081226: ROTSE-III Optical Limits
  67. GRB 081226: Swift detection of a possible short-hard burst
  68. GRB 080810: optical observations
  69. GRB 081211B: optical observations
  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. VLA radio upper limit on GRB 081222
  78. GRB 081222: Fermi GBM observation
  79. GRB 081221: Probable host galaxy in Keck imaging
  80. GRB 081204C: Fermi GBM detection
  81. GRB 081222, Swift-BAT refined analysis
  82. GRB 081221, Swift-BAT refined analysis
  83. GRB081222 optical limit by "Pi of the Sky"
  84. GRB 081222: Swift XRT refined analysis
  85. GRB081221: Fermi GBM observation
  86. IPN triangulation of bright GRB 081215A
  87. GRB 081222: Faulkes Telescope South observations
  88. GRB 081221: Gemini-N nIR imaging
  89. GRB081222, optical observation
  90. GRB081203A: BTA observation
  91. Konus-Wind observation of GRB 081221
  92. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  93. GRB081222: REM candidate afterglow
  94. GRB 081222: Swift detection of a burst with a bright optical afterglow
  95. GRB 081221: Enhanced Swift-XRT position
  96. GRB 081221: further NOT observations
  97. GRB 081221: NOT observations
  98. GRB 081221: Swift detection of a burst
  99. GRB 081217: Fermi GBM detection
  100. GRB 081211B: Further Swift-XRT analysis

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