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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"
  1. GRB 100510A: Fermi GBM detection/observation
  2. GRB 100511A: Fermi GBM detection/observation
  3. GRB 100511A: Super-LOTIS early observations
  4. Swift-BAT trigger 421695 is likely not astrophysical
  5. GRB100504A: Optical upper limits at IAO
  6. GRB 100510A: MAXI/GSC detection
  7. GRB 100511A, RIMOTS optical upper limits
  8. Trigger 421695: Swift detection of a possible burst
  9. GRB100508A: Further Swift/UVOT Observations
  10. GRB100503A: Suzaku WAM observation of the prompt emission
  11. GRB 100508A: GROND Detection of the optical afterglow
  12. GRB 100508A: Swift-XRT Refined analysis
  13. GRB 100508A: Swift-BAT refined analysis
  14. GRB 100508A: Enhanced Swift-XRT position
  15. GRB100508A: Swift/UVOT Detection of the Afterglow
  16. GRB 100508A: ROTSE-III Optical Limits
  17. GRB 100508A: Swift detection of a burst
  18. GRB 100418A: Keck imaging
  19. GRB 100418A: RTT150 optical observations
  20. Fermi Gamma-ray Burst Monitor trigger 294712621 is not a GRB
  21. Swift-BAT refined analysis of trigger 421262
  22. GRB 100504A: Fermi GBM observation
  23. An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73
  24. GRB 100504A: Swift/UVOT Observations
  25. GRB 100418A: Flattening of the Swift/UVOT Optical Light Curve
  26. GRB 100504A: Swift-XRT refined analysis
  27. GRB 100504A: Enhanced Swift-XRT position
  28. GRB 100504A: GROND Upper limits
  29. GRB 100504A: Swift-BAT refined analysis
  30. GRB 100504A: SARA-South Upper Limit
  31. GRB 100503A: Fermi GBM detection
  32. GRB 100504A: UVOT-enhanced XRT position
  33. GRB 100504A: Swift detection of a burst
  34. Swift-BAT trigger 421072 is not astrophyical
  35. INTEGRAL observations of Swift GRB trigger 421072
  36. GRB100423A : Suzaku WAM observation of the prompt emission
  37. Trigger 421072: Possible Swift detection of a GRB or transient
  38. GRB 100420A: EVLA radio observations
  39. GRB 100420A: Gemini discovery of infrared afterglow
  40. GRB 100423A: xinglong TNT optical upper limit
  41. GRB 100420A: Terskol optical upper limit
  42. GRB 100427A: Swift XRT and UVOT Upper Limits
  43. GRB 100427A: Fermi GBM detection
  44. GRB 100424a. Radio observations
  45. GRB 100418A: RTT150 optical observations
  46. GRB 100427A detected in ground analysis of Swift BAT data
  47. GRB 100414A : EVLA Radio Detection
  48. GRB 100414A : WSRT Radio Detection
  49. Konus-Wind observation of GRB 100423A
  50. GRB 100423A: CrAO optical observations
  51. GRB 100418A: Terskol optical observations
  52. GRB 100424A: CrAO optical observations
  53. GRB 100424A: NIR Afterglow Confirmation
  54. GRB 100425A: Swift XRT refined analysis
  55. GRB 100424A: Gemini/NIRI H-band observations
  56. GRB100425A: Swift/UVOT Upper Limits
  57. GRB 100424A: Swift/UVOT Upper Limits
  58. GRB 100424A: Liverpool Telescope Upper Limits
  59. GRB 100425A: Enhanced Swift-XRT position
  60. GRB 100425A: Swift-BAT refined analysis
  61. GRB 100425A: VLT/X-shooter redshift
  62. GRB 100425A: GROND afterglow observation
  63. GRB 100424A: Gemini/NIRI Candidate Afterglow
  64. GRB 100424A: D50 optical limits
  65. GRB 100425A: candidate optical afterglow from the VLT
  66. GRB100424A: MITSuME optical upper limits
  67. GRB100423A: MITSuME optical upper limits
  68. GRB 100424A : Lulin early z'-band upper limit
  69. GRB 100424A: GROND Upper Limits
  70. GRB 100424A: PAIRITEL NIR Upper Limits
  71. GRB 100424A: Swift-XRT refined analysis
  72. GRB 100425A: Swift detection of a burst
  73. GRB 100424A: WHT z-band observations
  74. GRB 100424A: NOT optical observations
  75. GRB 100424A, Swift-BAT refined analysis
  76. GRB 100424A: Enhanced Swift-XRT position
  77. GRB 100424A: Prompt enhanced Swift-XRT position.
  78. GRB 100424A: Swift detection of a burst
  79. GRB 100420A: GRT Optical Observation
  80. GRB 100418A: ROVOR optical measurements at 35 hours
  81. Swift-BAT refined analysis of trigger 420256
  82. Swift Trigger 420256: D50 optical limits
  83. GRB 100418A: Possible Evidence for a Supernova
  84. GRB 100420A: Swift-BAT refined analysis
  85. GRB 100423B: Fermi GBM detection
  86. GRB 100423A: Swift-BAT refined analysis
  87. Swift Trigger 420256: IAC80 R-band observations
  88. Swift Trigger 420256: BOOTES-2 observations
  89. Swift Trigger 420256: ROTSE-III Optical Limits
  90. Trigger 420256: Swift detection of a possible GRB
  91. GRB 100423A: Skynet/PROMPT Detections
  92. GRB 100423A: GROND discovery of afterglow
  93. GRB 100423A: Swift detection of a burst
  94. Radio afterglow detection of GRB 100418A with the EVLA
  95. GRB 100414A: Radio Afterglow Detection with the Expanded VLA
  96. GRB 100418A: Continued PAIRITEL NIR Observations
  97. GRB 100418A: WSRT Radio Detection
  98. GRB100418A: REM possible afterglow detection
  99. GRB 100418A: Continuing Swift/UVOT Observations
  100. GRB 100418A: further GROND observations and light curve fit

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