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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. Swift Trigger 420256: D50 optical limits
  2. GRB 100418A: Possible Evidence for a Supernova
  3. GRB 100420A: Swift-BAT refined analysis
  4. GRB 100423B: Fermi GBM detection
  5. GRB 100423A: Swift-BAT refined analysis
  6. Swift Trigger 420256: IAC80 R-band observations
  7. Swift Trigger 420256: BOOTES-2 observations
  8. Swift Trigger 420256: ROTSE-III Optical Limits
  9. Trigger 420256: Swift detection of a possible GRB
  10. GRB 100423A: Skynet/PROMPT Detections
  11. GRB 100423A: GROND discovery of afterglow
  12. GRB 100423A: Swift detection of a burst
  13. Radio afterglow detection of GRB 100418A with the EVLA
  14. GRB 100414A: Radio Afterglow Detection with the Expanded VLA
  15. GRB 100418A: Continued PAIRITEL NIR Observations
  16. GRB 100418A: WSRT Radio Detection
  17. GRB100418A: REM possible afterglow detection
  18. GRB 100418A: Continuing Swift/UVOT Observations
  19. GRB 100418A: further GROND observations and light curve fit
  20. GRB 100418A: RTT150 optical observations
  21. GRB100420A: MITSuME optical upper limits
  22. GRB 100414A: CFHT optical observations
  23. GRB 100420A: Swift/UVOT Upper Limits
  24. GRB 100420A: XRT refined analysis
  25. GRB 100420A: Enhanced Swift-XRT position
  26. GRB 100418A: SARA second epoch
  27. GRB 100420A: SARA Upper Limits
  28. GRB 100418A: RTT150 observations during the optical afterglow maximum
  29. GRB 100418A: optical observations
  30. GRB 100418A: MASTER-Net optical observations
  31. GRB 100414A: Confirmation of the X-ray afterglow
  32. GRB 100418A: VLT optical observations
  33. GRB 100418A: SMA submm detection
  34. GRB 100420A: ROTSE-III Optical Limits
  35. GRB 100420A: Swift detection of a burst
  36. GRB 100418A PAIRITEL NIR Observations
  37. GRB 100418A: ROVOR optical afterglow detection
  38. GRB 100418A: Swift/UVOT Observations
  39. GRB 100418A: Gemini-N redshift confirmation
  40. GRB 100413A: GMRT observation of radio afterglow
  41. GRB 100418A: Swift-XRT Refined Analysis
  42. GRB 100418A: host galaxy detection in the SDSS
  43. GRB100418A: VLT/X-shooter redshift and photometry
  44. GRB 100418A: SARA observations
  45. GRB100414A: SAO RAS optical observations
  46. GRB 100418A: GROND observations; missing author list added
  47. GRB 100418A: GROND observations
  48. GRB 100418A: Swift-BAT refined analysis
  49. GRB 100418A: Enhanced Swift-XRT position
  50. GRB 100418A: ROTSE-III Optical Limits
  51. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  52. GRB 100413A: Radio Afterglow Detection with the EVLA
  53. GRB 100414A: Suzaku WAM observation of the prompt emission
  54. GRB 100414A: Swift/UVOT Observations
  55. GRB 100414A: Gemini-N observation (correction)
  56. GRB 100414A: GROND Detection of the Optical Afterglow
  57. GRB 100414A: Gemini-N candidate and redshift
  58. GRB 100414A: Enhanced Swift-XRT position of candidate afterglow
  59. GRB 100413A: Suzaku WAM observation of the prompt emission
  60. GRB 100414A: Palomar Transient Factory Observations
  61. GRB 100413B: Swift Confirmation of Burst
  62. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  63. GRB 100413A: Swift-BAT final refined analysis
  64. GRB 100414A: IPN Localization
  65. Konus-Wind observation of GRB 100414A (correction to GCN 10597)
  66. Konus-Wind observation of GRB 100414B
  67. GRB 100415A: MAXI/GSC detection of a probable GRB
  68. GRB 100414A: Fermi GBM detection
  69. GRB100414A: Fermi LAT detection
  70. GRB 100413B : Swift detection of a burst
  71. GRB 100413A: GROND Upper limits
  72. GRB 100413A: Swift/UVOT Upper Limits
  73. Konus-Wind observation of GRB 100413A
  74. GRB 100413A: Faulkes Telescope South observations
  75. Tentative redshift of GRB100413A from X-ray data
  76. GRB 100413A: SARA upper limit
  77. GRB 100413A: Swift-XRT Refined Analysis
  78. GRB 100413A: Swift-BAT initial refined analysis
  79. GRB 100413A: Enhanced Swift-XRT position
  80. GRB 100413: xinglong TNT optical upper limit
  81. GRB 100413A: MASTER-Net optical observations
  82. GRB 100413A: Swift detection of a burst
  83. Spin down rate and inferred dipole magnetic field of the new soft gamma-ray repeater SGR 1833-0832
  84. Swift-BAT trigger 419015 is not astrophysical
  85. Trigger 419015 is probably not a GRB
  86. GRB100401A: GROND Upper Limits
  87. INTEGRAL Alert n. 5995: MASTER-Net optical observations
  88. MASTER observations on the Swift second trigger on LS V +44 17
  89. IBAS Alert n. 5996: not a GRB
  90. IBAS Alert n. 5995: not a GRB
  91. GRB 100331B: GROND Upper limits
  92. Master-Net observations on the Swift trigger on LS V +44 17
  93. GRB 100401A: Swift/UVOT Upper Limit
  94. Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
  95. GRB 100401A: Fermi GBM detection
  96. GRB 100401A Burst, possibly short, detected in ground analysis of BAT data
  97. GRB 100331B: BOOTES-3 observations
  98. GRB 100316A: R-band limit
  99. GRB 100324B: Suzaku WAM observation of the prompt emission
  100. GRB 100331B: Swift/UVOT Upper Limits

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