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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"

23413 results found.

  1. Detection of bright radio afterglow of GRB 090424 with the VLA
  2. GRB 090426: Enhanced Swift-XRT position
  3. GRB090426: Observation for Optical counterpart from MIRO
  4. GRB 090426, RIMOTS optical upper limits
  5. GRB 090426: Swift detection of a burst with an optical counterpart
  6. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  7. GRB 090424: MASTER-Net prompt optical limit
  8. VLA radio observation of high-z GRB 090423
  9. GRB090424: BVRI/R-band detection after 15 hrs burst
  10. GRB 090424: THO optical observations
  11. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  12. GRB090423: Y-band limit
  13. GRB 090423: Y-band field calibration update/correction
  14. GRB 090423: Swift/BAT spectral lag results
  15. GRB 090424 : TAOS optical detection
  16. GRB 090424: Liverpool Telescope observations
  17. GRB 090424: Optical observations from 1.23m CAHA
  18. GRB 090423: energetic, luminosity and jet break
  19. GRB 090424: MASTER-Net prompt optical observations
  20. GRB 090424: Enhanced Swift-XRT position
  21. GRB 090424: Swift-BAT refined analysis
  22. GRB 090424: Fermi GBM Observation
  23. GRB 090424: Swift detection of a burst with an optical counterpart
  24. GRB090423: Y-band field calibration
  25. GRB 090423 limiting magnitudes
  26. GRB 090423: Near infrared observation at Okayama Observatory
  27. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  28. GRB 090423: GROND detection and preliminary photo-z
  29. GRB 090423: NOT z-band limit
  30. GRB 090423: Swift-XRT refined analysis
  31. GRB090418A Rc-band photometry
  32. GRB090423 - Swift/UVOT upper limits.
  33. GRB 090423: NIR photometry and evidence for spectral break
  34. GRB 090422: Swift-XRT refined analysis
  35. GRB090423, RIMOTS optical upper limits
  36. GRB 090423: Enhanced Swift-XRT position
  37. GRB 090422: Swift/UVOT Upper Limits
  38. GRB 090423: UKIRT K-band observations
  39. GRB 090423: P60 Observations
  40. GRB 090418A: R and I band observation
  41. GRB 090423: Swift detection of a burst
  42. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  43. GRB 090422: Enhanced Swift-XRT position
  44. GRB 090418B: RTT150 optical observations
  45. GRB 080410: GAO 150cm telescope Optical Observation
  46. GRB 080408A: GAO 150cm telescope Optical Observation
  47. GRB 090418B: Suzaku WAM observation of the prompt emission
  48. GRB 090422: Swift detection of a burst
  49. GRB 090418C: Fermi GBM Detection
  50. Swift-BAT trigger 349718 is not a burst
  51. GRB 090418B: GRAS002 observatios
  52. GRB 090418B: GROND observations
  53. GRB 090419: Swift/UVOT Observations
  54. GRB 090418B: Faulkes Telescope North observations
  55. GRB 090418A: Swift/UVOT Observations
  56. GRB 090417B: Swift/UVOT Upper Limits
  57. GRB 090419: Swift-XRT refined analysis
  58. GRB 090419: GROND detection of afterglow candidate
  59. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  60. VLA radio detection of GRB 090418
  61. VLA radio upper limit on GRB 090417B
  62. GRB 090419: Enhanced Swift-XRT position
  63. GRB 090418: Swift XRT refined analysis
  64. GRB 090419: Swift detection of a burst
  65. VLA observations of short burst GRB 090417A
  66. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  67. GRB 090417B: Gemini imaging
  68. GRB 090417B: Swift-XRT refined analysis
  69. GRB 090418: Enhanced Swift-XRT position
  70. GRB 090418 Lick Redshift
  71. GRB 090418: Swift detection of a burst with optical afterglow
  72. GRB 090417B: Subaru NIR Observations
  73. GRB 090417B: MITSuME Okayama optical upper limits
  74. GRB090417B: Xinglong TNT optical upper limit
  75. GRB 090417B: optical observations
  76. GRB090417B: optical observations
  77. GRB 090417B: Swift detection of a burst
  78. GRB 090417: 2MASS galaxy within BAT Localization
  79. GRB 090417: Swift detection of a short burst
  80. GRB 090412: Fermi GBM detection
  81. GRB 090411B: Fermi GBM detection
  82. GRB 090411A: Fermi GBM detection
  83. GRB 090410: GROND upper limits
  84. GRB 090410: MITSuME optical upper limits
  85. GRB 090408b: IPN Triangulation
  86. GRB 090328b: IPN Triangulation
  87. GRB 090410: Swift detection of a burst
  88. Konus-Wind and Konus-RF observations of GRB 090408b
  89. GRB090408 : TAOS optical observations
  90. GRB 090409: Fermi GBM detection
  91. GRB090408, RIMOTS optical upper limits
  92. GRB 090408: Xinglong TNT optical Upper Limit
  93. Swift-BAT trigger 348781: almost certainly not a burst
  94. Fermi GBM Detection of a weak source
  95. GRB 090408B: MASTER II-Kourovka optical observations
  96. GRB 090408: Swift detection of a burst
  97. GRB 090407: GROND upper limits
  98. GRB 090407: VLT observations
  99. GRB 090407: Swift UVOT Upper Limits
  100. GRB 090407: Enhanced Swift-XRT position

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