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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"

21788 results found.

  1. GRB 090515: Swift detection of a short burst
  2. GRB 090510: Suzaku WAM observation of the prompt emission
  3. GRB 090510, Radio limits
  4. GRB090510: VLT/FORS2 spectroscopic redshift
  5. GRB 090510: GROND observations
  6. GRB 090509, further Swift-BAT refined analysis
  7. Konus-Wind observation of GRB 090510
  8. AGILE detection of GRB 090510
  9. GRB 090510: UVOT refined analysis
  10. GRB 090510: Enhanced Swift-XRT position
  11. GRB 090510: NOT afterglow confirmation
  12. GRB 090510: Fermi GBM detection
  13. Fermi LAT detection of GRB 090510
  14. GRB 090509, SMARTS optical/IR afterglow observations
  15. GRB 090510: Swift detection of a short hard burst
  16. GRB 090509: GROND further analysis and redshift limit
  17. GRB 090509: REM NIR afterglow
  18. GRB 090509: GROND afterglow candidate
  19. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  20. GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
  21. GRB 090427: GROND observations
  22. GRB 090429A: ROVOR magnitude limit
  23. GRB 090428B: Suzaku WAM observation of the prompt emission
  24. GRB 090424, SMARTS optical/IR afterglow monitoring
  25. GRB 090429B: Swift/UVOT Upper Limits
  26. GRB 090429A: Swift/UVOT Upper Limits
  27. GRB 090429B: Gemini-N further nIR observations
  28. GRB 090429A: GROND upper limits
  29. GRB 090429A: Enhanced Swift-XRT position
  30. GRB 090418A BVRcIc field calibration
  31. GRB 090426: GAO 150cm telescope Optical Observation
  32. GRB 090429B: RIMOTS optical upper limits
  33. GRB 090429B: Enhanced Swift-XRT position
  34. GRB090429B: Gemini-N infrared IR candidate
  35. GRB 090429B: VLT upper limits
  36. GRB 090429B: GROND Observations
  37. GRB 090429B: Super-LOTIS early observations
  38. GRB 090429B: Swift detection of a burst
  39. GRB 090429: Swift detection of a burst
  40. GRB 090424 : Multiband Optical observation from Nainital
  41. IPN triangulation of very bright GRB 090427
  42. GRB 090426: R-band limit
  43. GRB 090423: CARMA mm observations
  44. GRB 090424: Suzaku WAM observation of the prompt emission
  45. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  46. GRB 090423: GROND second epoch imaging and refined SED
  47. Detection of bright radio afterglow of GRB 090424 with the VLA
  48. GRB 090426: Enhanced Swift-XRT position
  49. GRB090426: Observation for Optical counterpart from MIRO
  50. GRB 090426, RIMOTS optical upper limits
  51. GRB 090426: Swift detection of a burst with an optical counterpart
  52. GRB 090424: MASTER-Net prompt optical limit
  53. VLA radio observation of high-z GRB 090423
  54. GRB 090424: THO optical observations
  55. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  56. GRB 090423: Y-band field calibration update/correction
  57. GRB 090424 : TAOS optical detection
  58. GRB 090424: Liverpool Telescope observations
  59. GRB 090424: Optical observations from 1.23m CAHA
  60. GRB 090424: MASTER-Net prompt optical observations
  61. GRB 090424: Enhanced Swift-XRT position
  62. GRB 090424: Swift-BAT refined analysis
  63. GRB 090424: Fermi GBM Observation
  64. GRB 090424: Swift detection of a burst with an optical counterpart
  65. GRB090423: Y-band field calibration
  66. GRB 090423 limiting magnitudes
  67. GRB 090423: Near infrared observation at Okayama Observatory
  68. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  69. GRB 090423: GROND detection and preliminary photo-z
  70. GRB 090423: NOT z-band limit
  71. GRB090418A Rc-band photometry
  72. GRB 090423: NIR photometry and evidence for spectral break
  73. GRB090423, RIMOTS optical upper limits
  74. GRB 090423: Enhanced Swift-XRT position
  75. GRB 090422: Swift/UVOT Upper Limits
  76. GRB 090423: UKIRT K-band observations
  77. GRB 090423: P60 Observations
  78. GRB 090418A: R and I band observation
  79. GRB 090423: Swift detection of a burst
  80. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  81. GRB 090422: Enhanced Swift-XRT position
  82. GRB 090418B: RTT150 optical observations
  83. GRB 080410: GAO 150cm telescope Optical Observation
  84. GRB 080408A: GAO 150cm telescope Optical Observation
  85. GRB 090418B: Suzaku WAM observation of the prompt emission
  86. GRB 090422: Swift detection of a burst
  87. GRB 090418B: GRAS002 observatios
  88. GRB 090417B: Optical observation
  89. GRB 090418B: GROND observations
  90. GRB 090419: Swift/UVOT Observations
  91. GRB 090418B: Faulkes Telescope North observations
  92. GRB 090418A: Swift/UVOT Observations
  93. GRB 090417B: Swift/UVOT Upper Limits
  94. GRB 090419: Swift-XRT refined analysis
  95. Konus-Wind observation of GRB 090418B
  96. GRB 090419: GROND detection of afterglow candidate
  97. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  98. VLA radio detection of GRB 090418
  99. VLA radio upper limit on GRB 090417B
  100. GRB 090419: Enhanced Swift-XRT position

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