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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"

27397 results found.

  1. GRB 090424 : TAOS optical detection
  2. GRB 090424: Liverpool Telescope observations
  3. GRB 090424: Swift-XRT refined analysis
  4. GRB 090424: Optical observations from 1.23m CAHA
  5. GRB 090423: energetic, luminosity and jet break
  6. GRB 090424: MASTER-Net prompt optical observations
  7. GRB 090424: Enhanced Swift-XRT position
  8. GRB 090424: Swift-BAT refined analysis
  9. GRB 090423: Fermi GBM observation
  10. GRB 090424: Swift detection of a burst with an optical counterpart
  11. GRB090423: Y-band field calibration
  12. GRB 090423 limiting magnitudes
  13. GRB 090423: Near infrared observation at Okayama Observatory
  14. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  15. GRB 090423: GROND detection and preliminary photo-z
  16. GRB 090423: NOT z-band limit
  17. GRB 090423: Swift-XRT refined analysis
  18. GRB090418A Rc-band photometry
  19. GRB 090423: NIR photometry and evidence for spectral break
  20. GRB 090422: Swift-XRT refined analysis
  21. GRB090423, RIMOTS optical upper limits
  22. GRB 090423: Enhanced Swift-XRT position
  23. GRB 090423: Swift-BAT refined analysis
  24. GRB 090422: Swift/UVOT Upper Limits
  25. GRB 090423: UKIRT K-band observations
  26. GRB 090423: P60 Observations
  27. GRB 090418A: R and I band observation
  28. GRB 090423: Swift detection of a burst
  29. GRB 090422: Liverpool Telescope possible candidate
  30. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  31. GRB 090422: Swift-BAT refined analysis
  32. GRB 090422: Enhanced Swift-XRT position
  33. GRB 090418B: RTT150 optical observations
  34. GRB 080410: GAO 150cm telescope Optical Observation
  35. GRB 080408A: GAO 150cm telescope Optical Observation
  36. GRB 090422: Liverpool Telescope observations
  37. GRB 090418B: Suzaku WAM observation of the prompt emission
  38. GRB 090422: Swift detection of a burst
  39. GRB 090418C: Fermi GBM Detection
  40. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  41. GRB 090418B: GRAS002 observatios
  42. GRB 090418B: GROND observations
  43. GRB 090419: Swift/UVOT Observations
  44. GRB 090418B: Faulkes Telescope North observations
  45. GRB 090418A: Swift/UVOT Observations
  46. GRB 090417B: Swift/UVOT Upper Limits
  47. GRB 090417B Correction to the BAT refined analysis position
  48. GRB 090419: Swift-XRT refined analysis
  49. Konus-Wind observation of GRB 090418B
  50. GRB 090419: GROND detection of afterglow candidate
  51. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  52. GRB 090419: Swift-BAT refined analysis
  53. VLA radio detection of GRB 090418
  54. VLA radio upper limit on GRB 090417B
  55. GRB 090419: Enhanced Swift-XRT position
  56. GRB 090418: Swift XRT refined analysis
  57. GRB 090419: Swift detection of a burst
  58. VLA observations of short burst GRB 090417A
  59. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  60. GRB 090417B: Gemini imaging
  61. GRB 090418: Swift-BAT refined analysis
  62. GRB 090417B: Swift-XRT refined analysis
  63. GRB 090418: Enhanced Swift-XRT position
  64. GRB 090418: Swift detection of a burst with optical afterglow
  65. GRB 090411B: Suzaku WAM observation of the prompt emission
  66. GRB 090411A: Suzaku WAM observation of the prompt emission
  67. GRB 090417B: Subaru NIR Observations
  68. GRB 090417B: MITSuME Okayama optical upper limits
  69. GRB 090417B: optical observations
  70. GRB090417B: optical observations
  71. GRB 090417B: Swift-BAT refined analysis
  72. GRB 090417A: Swift-BAT refined analysis
  73. GRB 090417A: Early-type nature of the putative host
  74. GRB 090417A: nearby galaxy redshift
  75. GRB 090417B: Swift detection of a burst
  76. GRB 090412: Fermi GBM detection
  77. GRB 090411B: Fermi GBM detection
  78. GRB 090411A: Fermi GBM detection
  79. GRB 090410: Suzaku WAM observation of the prompt emission
  80. GRB 090410: GROND upper limits
  81. GRB 090410: MITSuME optical upper limits
  82. GRB 090408b: IPN Triangulation
  83. GRB 090328b: IPN Triangulation
  84. GRB 090410: Swift-BAT refined analysis
  85. GRB 090409: Fermi GBM detection
  86. GRB090408, RIMOTS optical upper limits
  87. Swift-BAT trigger 348781: almost certainly not a burst
  88. GRB 090408B: MASTER II-Kourovka optical observations
  89. GRB 090407: GROND upper limits
  90. GRB 090407: VLT observations
  91. GRB 090407: Swift-XRT refined analysis
  92. GRB 090407: Swift UVOT Upper Limits
  93. GRB 090407: Enhanced Swift-XRT position
  94. GRB 090407: Swift-BAT refined analysis
  95. GRB 090407: ROTSE-III Optical Limits
  96. GRB 090407: Swift detection of a burst
  97. GRB 090404: millimeter detection
  98. GRB 090405: Fermi GBM Detection
  99. GRB 090403: Fermi GBM detection
  100. GRB 090404: GROND upper limits

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