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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"

20388 results found.

  1. GRB 090424 : Multiband Optical observation from Nainital
  2. IPN triangulation of very bright GRB 090427
  3. GRB 090423: CARMA mm observations
  4. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  5. GRB 090423: GROND second epoch imaging and refined SED
  6. Detection of bright radio afterglow of GRB 090424 with the VLA
  7. GRB 090426: Enhanced Swift-XRT position
  8. GRB090426: Observation for Optical counterpart from MIRO
  9. GRB 090426, RIMOTS optical upper limits
  10. GRB 090426: Swift detection of a burst with an optical counterpart
  11. GRB 090424: MASTER-Net prompt optical limit
  12. VLA radio observation of high-z GRB 090423
  13. GRB 090424: THO optical observations
  14. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  15. GRB 090423: Y-band field calibration update/correction
  16. GRB 090424 : TAOS optical detection
  17. GRB 090424: Liverpool Telescope observations
  18. GRB 090424: Optical observations from 1.23m CAHA
  19. GRB 090423: energetic, luminosity and jet break
  20. GRB 090424: MASTER-Net prompt optical observations
  21. GRB 090424: Enhanced Swift-XRT position
  22. GRB 090424: Swift detection of a burst with an optical counterpart
  23. GRB090423: Y-band field calibration
  24. GRB 090423 limiting magnitudes
  25. GRB 090423: Near infrared observation at Okayama Observatory
  26. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  27. GRB 090423: GROND detection and preliminary photo-z
  28. GRB 090423: NOT z-band limit
  29. GRB090418A Rc-band photometry
  30. GRB 090423: NIR photometry and evidence for spectral break
  31. GRB090423, RIMOTS optical upper limits
  32. GRB 090423: Enhanced Swift-XRT position
  33. GRB 090423: Swift-BAT refined analysis
  34. GRB 090422: Swift/UVOT Upper Limits
  35. GRB 090423: UKIRT K-band observations
  36. GRB 090423: P60 Observations
  37. GRB 090418A: R and I band observation
  38. GRB 090423: Swift detection of a burst
  39. GRB 090422: Enhanced Swift-XRT position
  40. GRB 090418B: RTT150 optical observations
  41. GRB 080410: GAO 150cm telescope Optical Observation
  42. GRB 080408A: GAO 150cm telescope Optical Observation
  43. GRB 090422: Swift detection of a burst
  44. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  45. GRB 090418B: GRAS002 observatios
  46. GRB 090418A: optical observations
  47. GRB 090418B: GROND observations
  48. GRB 090419: Swift/UVOT Observations
  49. GRB 090418B: Faulkes Telescope North observations
  50. GRB 090418A: Swift/UVOT Observations
  51. GRB 090417B: Swift/UVOT Upper Limits
  52. GRB 090419: Swift-XRT refined analysis
  53. GRB 090419: GROND detection of afterglow candidate
  54. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  55. VLA radio detection of GRB 090418
  56. VLA radio upper limit on GRB 090417B
  57. GRB 090419: Enhanced Swift-XRT position
  58. GRB 090418: Swift XRT refined analysis
  59. GRB 090419: Swift detection of a burst
  60. VLA observations of short burst GRB 090417A
  61. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  62. GRB 090417B: Gemini imaging
  63. GRB 090418: Enhanced Swift-XRT position
  64. GRB 090418: Swift detection of a burst with optical afterglow
  65. GRB 090417B: Subaru NIR Observations
  66. GRB 090417B: MITSuME Okayama optical upper limits
  67. GRB 090417B: optical observations
  68. GRB090417B: optical observations
  69. GRB 090417B: Swift detection of a burst
  70. GRB 090411A: Fermi GBM detection
  71. GRB 090410: GROND upper limits
  72. GRB 090410: MITSuME optical upper limits
  73. GRB 090408b: IPN Triangulation
  74. GRB 090328b: IPN Triangulation
  75. Konus-Wind and Konus-RF observations of GRB 090408b
  76. GRB 090409: Fermi GBM detection
  77. GRB090408, RIMOTS optical upper limits
  78. Swift-BAT trigger 348781: almost certainly not a burst
  79. GRB 090408B: MASTER II-Kourovka optical observations
  80. GRB 090407: GROND upper limits
  81. GRB 090407: VLT observations
  82. GRB 090407: Swift UVOT Upper Limits
  83. GRB 090407: Enhanced Swift-XRT position
  84. GRB 090407: ROTSE-III Optical Limits
  85. GRB 090407: Swift detection of a burst
  86. GRB 090404: GROND upper limits
  87. GRB 090404: further NOT observations
  88. Swift/UVOT observations of GRB090404
  89. GRB 090404: NOT observations
  90. GRB 090404: Enhanced Swift-XRT position
  91. GRB 090404: Swift detection of a burst
  92. GRB 090401B: VLA radio upper limit
  93. GRB 090401B: Upper limits of MITSuME optical observation
  94. GRB090401B, RIMOTS optical upper limits
  95. GRB 090401B: AGILE refined analysis
  96. GRB 090401B: Enhanced Swift-XRT position
  97. AGILE Gamma-ray detection of GRB 090401B
  98. GRB 090401B: Swift detection of a burst
  99. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  100. GRB 090323: Further TLS detections - a break?

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