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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"

28050 results found.

  1. GRB 090419: Swift-XRT refined analysis
  2. Konus-Wind observation of GRB 090418B
  3. GRB 090419: GROND detection of afterglow candidate
  4. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  5. GRB 090419: Swift-BAT refined analysis
  6. VLA radio detection of GRB 090418
  7. VLA radio upper limit on GRB 090417B
  8. GRB 090419: Enhanced Swift-XRT position
  9. GRB 090418: Swift XRT refined analysis
  10. GRB 090419: Swift detection of a burst
  11. VLA observations of short burst GRB 090417A
  12. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  13. GRB 090417B: Gemini imaging
  14. GRB 090418: Swift-BAT refined analysis
  15. GRB 090417B: Swift-XRT refined analysis
  16. GRB 090418: Enhanced Swift-XRT position
  17. GRB 090418: Swift detection of a burst with optical afterglow
  18. GRB 090411B: Suzaku WAM observation of the prompt emission
  19. GRB 090411A: Suzaku WAM observation of the prompt emission
  20. GRB 090417B: Subaru NIR Observations
  21. GRB 090417B: MITSuME Okayama optical upper limits
  22. GRB 090417B: optical observations
  23. GRB090417B: optical observations
  24. GRB 090417B: Swift-BAT refined analysis
  25. GRB 090417A: Swift-BAT refined analysis
  26. GRB 090417A: Early-type nature of the putative host
  27. GRB 090417A: nearby galaxy redshift
  28. GRB 090417B: Swift detection of a burst
  29. GRB 090412: Fermi GBM detection
  30. GRB 090411B: Fermi GBM detection
  31. GRB 090411A: Fermi GBM detection
  32. GRB 090410: Suzaku WAM observation of the prompt emission
  33. GRB 090410: GROND upper limits
  34. GRB 090410: MITSuME optical upper limits
  35. GRB 090408b: IPN Triangulation
  36. GRB 090328b: IPN Triangulation
  37. GRB 090410: Swift-BAT refined analysis
  38. GRB 090409: Fermi GBM detection
  39. GRB090408, RIMOTS optical upper limits
  40. Swift-BAT trigger 348781: almost certainly not a burst
  41. GRB 090408B: MASTER II-Kourovka optical observations
  42. GRB 090407: GROND upper limits
  43. GRB 090407: VLT observations
  44. GRB 090407: Swift-XRT refined analysis
  45. GRB 090407: Swift UVOT Upper Limits
  46. GRB 090407: Enhanced Swift-XRT position
  47. GRB 090407: Swift-BAT refined analysis
  48. GRB 090407: ROTSE-III Optical Limits
  49. GRB 090407: Swift detection of a burst
  50. GRB 090404: millimeter detection
  51. GRB 090405: Fermi GBM Detection
  52. GRB 090403: Fermi GBM detection
  53. GRB 090404: GROND upper limits
  54. GRB 090404: further NOT observations
  55. Swift/UVOT observations of GRB090404
  56. GRB 090404: NOT observations
  57. GRB 090404: Swift-XRT Team refined analysis
  58. GRB 090404: Swift-BAT refined analysis
  59. GRB 090404: Enhanced Swift-XRT position
  60. GRB 090404: Swift detection of a burst
  61. GRB 090401A: Suzaku WAM observation of the prompt emission
  62. GRB 090401B: Suzaku WAM observation of the prompt emission
  63. GRB 090401B: Xinglong TNT optical Upper Limit
  64. GRB 090401B: VLA radio upper limit
  65. GRB 090401B: Upper limits of MITSuME optical observation
  66. GRB090401B, RIMOTS optical upper limits
  67. GRB 090401B: AGILE refined analysis
  68. GRB 090401B: Swift XRT Refined Analysis
  69. GRB 090331: Fermi GBM detection
  70. Konus-Wind observation of GRB 090401A
  71. GRB 090401B: Enhanced Swift-XRT position
  72. AGILE Gamma-ray detection of GRB 090401B
  73. GRB 090401B: Swift-BAT refined analysis
  74. GRB 090401B: Swift detection of a burst
  75. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  76. GRB 090401, Swift-BAT refined analysis
  77. GRB 090323: Further TLS detections - a break?
  78. GRB 090324: Suzaku WAM observation of the prompt emission
  79. GRB 090328: Radio afterglow detection
  80. GRB 090326: Fermi GBM detection
  81. GRB 090328: Fermi GBM Spectral Analysis
  82. GRB 090328B: Fermi GBM Detection
  83. GRB 090330: Fermi GBM detection
  84. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  85. GRB 090328: Swift XRT refined analysis
  86. GRB090323: Optical observations from NOT
  87. GRB 090328: Swift UVOT observations
  88. GRB 090328: Updated position/optical afterglow candidate
  89. Fermi LAT and GBM detections of GRB090328
  90. GRB 090323: Radio afterglow detection
  91. GRB 090327: Fermi GBM detection
  92. GRB 090320B: MASTER-Net prompt optical observations
  93. GRB 090323: Fermi GBM Spectral Analysis
  94. GRB 090323: UVOT Detection of Afterglow
  95. GRB 090324: SuperAGILE Localization of a Long GRB
  96. GRB 090323: P60 Afterglow Confirmation
  97. GRB 090323: GROND Detection of the Afterglow and Photo-z
  98. GRB 090323: Possible XRT Counterpart
  99. GRB 090320C: Fermi GBM Detection
  100. GRB 090320B: Fermi GBM detection.

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