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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"

19551 results found.

  1. VLA radio upper limit on GRB 090417B
  2. GRB 090419: Enhanced Swift-XRT position
  3. GRB 090419: Swift detection of a burst
  4. VLA observations of short burst GRB 090417A
  5. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  6. GRB 090417B: Gemini imaging
  7. GRB 090418: Swift-BAT refined analysis
  8. GRB 090418: Enhanced Swift-XRT position
  9. GRB 090418: Swift detection of a burst with optical afterglow
  10. GRB 090417B: Subaru NIR Observations
  11. GRB 090417B: MITSuME Okayama optical upper limits
  12. GRB090417B: Xinglong TNT optical upper limit
  13. GRB 090417B: optical observations
  14. GRB090417B: optical observations
  15. GRB 090417A: Swift-BAT refined analysis
  16. GRB 090417B: Swift detection of a burst
  17. GRB 090412: Fermi GBM detection
  18. GRB 090411B: Fermi GBM detection
  19. GRB 090411A: Fermi GBM detection
  20. GRB 090410: Suzaku WAM observation of the prompt emission
  21. GRB 090410: GROND upper limits
  22. GRB 090410: MITSuME optical upper limits
  23. GRB 090408b: IPN Triangulation
  24. GRB 090328b: IPN Triangulation
  25. GRB 090410: Swift-BAT refined analysis
  26. Konus-Wind and Konus-RF observations of GRB 090408b
  27. GRB 090409: Fermi GBM detection
  28. GRB090408, RIMOTS optical upper limits
  29. Swift-BAT trigger 348781: almost certainly not a burst
  30. GRB 090408B: MASTER II-Kourovka optical observations
  31. GRB 090407: GROND upper limits
  32. GRB 090407: VLT observations
  33. GRB 090407: Swift UVOT Upper Limits
  34. GRB 090407: Enhanced Swift-XRT position
  35. GRB 090407: ROTSE-III Optical Limits
  36. GRB 090407: Swift detection of a burst
  37. GRB 090404: GROND upper limits
  38. GRB 090404: further NOT observations
  39. Swift/UVOT observations of GRB090404
  40. GRB 090404: NOT observations
  41. GRB 090404: Enhanced Swift-XRT position
  42. GRB 090404: Swift detection of a burst
  43. GRB 090401B: VLA radio upper limit
  44. GRB 090401B: Upper limits of MITSuME optical observation
  45. GRB090401B, RIMOTS optical upper limits
  46. GRB 090401B: Enhanced Swift-XRT position
  47. AGILE Gamma-ray detection of GRB 090401B
  48. GRB 090401B: Swift detection of a burst
  49. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  50. GRB 090328: Radio afterglow detection
  51. GRB 090326: Fermi GBM detection
  52. GRB 090328: Fermi GBM Spectral Analysis
  53. GRB 090328B: Fermi GBM Detection
  54. GRB 090330: Fermi GBM detection
  55. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  56. GRB090323: Optical observations from NOT
  57. Konus-Wind observation of GRB 090328
  58. GRB 090328: Swift UVOT observations
  59. GRB 090328: Updated position/optical afterglow candidate
  60. GRB 090323: Radio afterglow detection
  61. GRB 090327: Fermi GBM detection
  62. GRB 090320B: MASTER-Net prompt optical observations
  63. GRB 090323: Fermi GBM Spectral Analysis
  64. GRB 090323 TLS detection - still bright
  65. GRB 090323: UVOT Detection of Afterglow
  66. GRB 090323: P60 Afterglow Confirmation
  67. GRB 090323: GROND Detection of the Afterglow and Photo-z
  68. GRB 090323: Possible XRT Counterpart
  69. GRB 090320C: Fermi GBM Detection
  70. GRB 090320B: Fermi GBM detection.
  71. GRB 090319: Fermi GBM detection
  72. GRB 090320A: Fermi GBM detection
  73. Further 15GHz observations of GRB090313
  74. X-shooter observations of GRB 090313
  75. GRB090313: radio detection with the VLA
  76. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  77. Further radio observation of GRB 090313
  78. GRB 090313: detection with CARMA in 3mm band
  79. GRB090305B: MASTER-net prompt optical short burst observations
  80. GRB 090313: MITSuME Okayama observation
  81. GRB 090313: Additional Gemini-S photometry
  82. GRB 090313: TAROT La Silla observatory optical detection
  83. GRB 090313: Zadko Telescope observations
  84. GRB 090313: Ongoing plateau phase
  85. GRB 090313: Swift-XRT refined analysis
  86. GRB 090313: Swift/UVOT upper limits
  87. GRB 090313, GROND observations
  88. Swift trigger 346250 is probably not a burst
  89. GRB090310: Fermi GBM detection
  90. GRB 090205: Zadko Telescope late-time observations
  91. GRB 090309A: GROND upper limits
  92. GRB 090307A: TAROT Calern observatory optical observations
  93. GRB 090309: Swift/UVOT Upper Limits
  94. GRB090305B: Fermi GBM detection
  95. GRB 090309B: Fermi GBM detection
  96. GRB 090309: Enhanced Swift-XRT position
  97. GRB 090308: GROND observations
  98. GRB 090308: Gemini GMOS Observations
  99. GRB 090309: Swift detection of a burst
  100. GRB 090308B: Fermi GBM detection

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