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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"

19093 results found.

  1. GRB 090424: Swift-XRT refined analysis
  2. GRB 090424: Optical observations from 1.23m CAHA
  3. GRB 090423: energetic, luminosity and jet break
  4. GRB 090424: MASTER-Net prompt optical observations
  5. GRB 090424: Enhanced Swift-XRT position
  6. GRB 090424: Fermi GBM Observation
  7. GRB 090423: Fermi GBM observation
  8. GRB 090422: Fermi GBM observation
  9. GRB 090423: Ep,i - Eiso correlation
  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. GRB090418A Rc-band photometry
  18. GRB 090423: NIR photometry and evidence for spectral break
  19. GRB090423, RIMOTS optical upper limits
  20. GRB 090423: Enhanced Swift-XRT position
  21. GRB 090422: Swift/UVOT Upper Limits
  22. GRB 090423: UKIRT K-band observations
  23. GRB 090423: P60 Observations
  24. GRB 090418A: R and I band observation
  25. GRB 090423: Swift detection of a burst
  26. GRB 090422: Swift-BAT refined analysis
  27. GRB 090422: Enhanced Swift-XRT position
  28. GRB 090418B: RTT150 optical observations
  29. GRB 080410: GAO 150cm telescope Optical Observation
  30. GRB 080408A: GAO 150cm telescope Optical Observation
  31. GRB 090422: Swift detection of a burst
  32. GRB 090418C: Fermi GBM Detection
  33. GRB 090418B: GRAS002 observatios
  34. GRB 090418B: GROND observations
  35. GRB 090419: Swift/UVOT Observations
  36. GRB 090418B: Faulkes Telescope North observations
  37. GRB 090418A: Swift/UVOT Observations
  38. GRB 090417B: Swift/UVOT Upper Limits
  39. Konus-Wind observation of GRB 090418B
  40. GRB 090419: GROND detection of afterglow candidate
  41. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  42. VLA radio detection of GRB 090418
  43. VLA radio upper limit on GRB 090417B
  44. GRB 090419: Enhanced Swift-XRT position
  45. GRB 090419: Swift detection of a burst
  46. VLA observations of short burst GRB 090417A
  47. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  48. GRB 090417B: Gemini imaging
  49. GRB 090418: Swift-BAT refined analysis
  50. GRB 090418: Enhanced Swift-XRT position
  51. GRB 090418: Swift detection of a burst with optical afterglow
  52. GRB 090417B: Subaru NIR Observations
  53. GRB 090417B: MITSuME Okayama optical upper limits
  54. GRB090417B: Xinglong TNT optical upper limit
  55. GRB 090417B: optical observations
  56. GRB090417B: optical observations
  57. GRB 090417A: Swift-BAT refined analysis
  58. GRB 090417B: Swift detection of a burst
  59. GRB 090412: Fermi GBM detection
  60. GRB 090411B: Fermi GBM detection
  61. GRB 090411A: Fermi GBM detection
  62. GRB 090410: Suzaku WAM observation of the prompt emission
  63. GRB 090410: GROND upper limits
  64. GRB 090410: MITSuME optical upper limits
  65. GRB 090408b: IPN Triangulation
  66. GRB 090328b: IPN Triangulation
  67. GRB 090410: Swift-BAT refined analysis
  68. Konus-Wind and Konus-RF observations of GRB 090408b
  69. GRB 090409: Fermi GBM detection
  70. GRB090408, RIMOTS optical upper limits
  71. Swift-BAT trigger 348781: almost certainly not a burst
  72. GRB 090408B: MASTER II-Kourovka optical observations
  73. GRB 090407: GROND upper limits
  74. GRB 090407: VLT observations
  75. GRB 090407: Swift UVOT Upper Limits
  76. GRB 090407: Enhanced Swift-XRT position
  77. GRB 090407: ROTSE-III Optical Limits
  78. GRB 090407: Swift detection of a burst
  79. GRB 090404: GROND upper limits
  80. GRB 090404: further NOT observations
  81. Swift/UVOT observations of GRB090404
  82. GRB 090404: NOT observations
  83. GRB 090404: Enhanced Swift-XRT position
  84. GRB 090404: Swift detection of a burst
  85. GRB 090401B: VLA radio upper limit
  86. GRB 090401B: Upper limits of MITSuME optical observation
  87. GRB090401B, RIMOTS optical upper limits
  88. GRB 090401B: Enhanced Swift-XRT position
  89. AGILE Gamma-ray detection of GRB 090401B
  90. GRB 090401B: Swift detection of a burst
  91. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  92. GRB 090328: Radio afterglow detection
  93. GRB 090326: Fermi GBM detection
  94. GRB 090328: Fermi GBM Spectral Analysis
  95. GRB 090328B: Fermi GBM Detection
  96. GRB 090330: Fermi GBM detection
  97. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  98. GRB090323: Optical observations from NOT
  99. Konus-Wind observation of GRB 090328
  100. GRB 090328: Swift UVOT observations

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