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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"

21264 results found.

  1. GRB 090429B: Swift/UVOT Upper Limits
  2. GRB 090429A: Swift/UVOT Upper Limits
  3. GRB 090429B: Gemini-N further nIR observations
  4. GRB 090429A: GROND upper limits
  5. GRB 090429A: Enhanced Swift-XRT position
  6. GRB 090418A BVRcIc field calibration
  7. GRB 090426: GAO 150cm telescope Optical Observation
  8. GRB 090429B: RIMOTS optical upper limits
  9. GRB 090429B: Enhanced Swift-XRT position
  10. GRB090429B: Gemini-N infrared IR candidate
  11. GRB 090429B: VLT upper limits
  12. GRB 090429B: GROND Observations
  13. GRB 090429B: Super-LOTIS early observations
  14. GRB 090429B: Swift detection of a burst
  15. GRB 090429: Swift detection of a burst
  16. GRB 090424 : Multiband Optical observation from Nainital
  17. IPN triangulation of very bright GRB 090427
  18. GRB 090426: R-band limit
  19. GRB 090423: CARMA mm observations
  20. GRB 090424: Suzaku WAM observation of the prompt emission
  21. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  22. GRB 090423: GROND second epoch imaging and refined SED
  23. Detection of bright radio afterglow of GRB 090424 with the VLA
  24. GRB 090426: Enhanced Swift-XRT position
  25. GRB090426: Observation for Optical counterpart from MIRO
  26. GRB 090426, RIMOTS optical upper limits
  27. GRB 090426: Swift detection of a burst with an optical counterpart
  28. GRB 090424: MASTER-Net prompt optical limit
  29. VLA radio observation of high-z GRB 090423
  30. GRB 090424: THO optical observations
  31. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  32. GRB 090423: Y-band field calibration update/correction
  33. GRB 090424 : TAOS optical detection
  34. GRB 090424: Liverpool Telescope observations
  35. GRB 090424: Optical observations from 1.23m CAHA
  36. GRB 090424: MASTER-Net prompt optical observations
  37. GRB 090424: Enhanced Swift-XRT position
  38. GRB 090424: Swift-BAT refined analysis
  39. GRB 090424: Fermi GBM Observation
  40. GRB 090424: Swift detection of a burst with an optical counterpart
  41. GRB090423: Y-band field calibration
  42. GRB 090423 limiting magnitudes
  43. GRB 090423: Near infrared observation at Okayama Observatory
  44. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  45. GRB 090423: GROND detection and preliminary photo-z
  46. GRB 090423: NOT z-band limit
  47. GRB090418A Rc-band photometry
  48. GRB 090423: NIR photometry and evidence for spectral break
  49. GRB090423, RIMOTS optical upper limits
  50. GRB 090423: Enhanced Swift-XRT position
  51. GRB 090422: Swift/UVOT Upper Limits
  52. GRB 090423: UKIRT K-band observations
  53. GRB 090423: P60 Observations
  54. GRB 090418A: R and I band observation
  55. GRB 090423: Swift detection of a burst
  56. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  57. GRB 090422: Enhanced Swift-XRT position
  58. GRB 090418B: RTT150 optical observations
  59. GRB 080410: GAO 150cm telescope Optical Observation
  60. GRB 080408A: GAO 150cm telescope Optical Observation
  61. GRB 090418B: Suzaku WAM observation of the prompt emission
  62. GRB 090422: Swift detection of a burst
  63. GRB 090418B: GRAS002 observatios
  64. GRB 090417B: Optical observation
  65. GRB 090418B: GROND observations
  66. GRB 090419: Swift/UVOT Observations
  67. GRB 090418B: Faulkes Telescope North observations
  68. GRB 090418A: Swift/UVOT Observations
  69. GRB 090417B: Swift/UVOT Upper Limits
  70. GRB 090419: Swift-XRT refined analysis
  71. Konus-Wind observation of GRB 090418B
  72. GRB 090419: GROND detection of afterglow candidate
  73. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  74. VLA radio detection of GRB 090418
  75. VLA radio upper limit on GRB 090417B
  76. GRB 090419: Enhanced Swift-XRT position
  77. GRB 090418A: ROTSE-III Refined Analysis
  78. GRB 090419: Swift detection of a burst
  79. VLA observations of short burst GRB 090417A
  80. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  81. GRB 090417B: Gemini imaging
  82. GRB 090418: Swift-BAT refined analysis
  83. GRB 090418: Enhanced Swift-XRT position
  84. GRB 090418: Swift detection of a burst with optical afterglow
  85. GRB 090411B: Suzaku WAM observation of the prompt emission
  86. GRB 090411A: Suzaku WAM observation of the prompt emission
  87. GRB 090417B: Subaru NIR Observations
  88. GRB 090417B: MITSuME Okayama optical upper limits
  89. GRB 090417B: optical observations
  90. GRB090417B: optical observations
  91. GRB 090417B: Swift detection of a burst
  92. GRB 090410: Suzaku WAM observation of the prompt emission
  93. GRB 090410: GROND upper limits
  94. GRB 090410: MITSuME optical upper limits
  95. GRB 090408b: IPN Triangulation
  96. GRB 090328b: IPN Triangulation
  97. GRB090408, RIMOTS optical upper limits
  98. Swift-BAT trigger 348781: almost certainly not a burst
  99. GRB 090408B: MASTER II-Kourovka optical observations
  100. GRB 090407: GROND upper limits

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