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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. GRB100418A: REM possible afterglow detection
  2. GRB 100418A: Continuing Swift/UVOT Observations
  3. GRB 100418A: further GROND observations and light curve fit
  4. GRB 100418A: RTT150 optical observations
  5. GRB100420A: MITSuME optical upper limits
  6. GRB 100414A: CFHT optical observations
  7. GRB 100420A: Swift/UVOT Upper Limits
  8. GRB 100420A: XRT refined analysis
  9. GRB 100420A: Enhanced Swift-XRT position
  10. GRB 100418A: SARA second epoch
  11. GRB 100420A: SARA Upper Limits
  12. GRB 100418A: RTT150 observations during the optical afterglow maximum
  13. GRB 100418A: optical observations
  14. GRB 100418A: MASTER-Net optical observations
  15. GRB 100414A: Confirmation of the X-ray afterglow
  16. GRB 100418A: VLT optical observations
  17. GRB 100418A: SMA submm detection
  18. GRB 100420A: ROTSE-III Optical Limits
  19. GRB 100420A: Swift detection of a burst
  20. GRB 100418A PAIRITEL NIR Observations
  21. GRB 100418A: ROVOR optical afterglow detection
  22. GRB 100418A: Swift/UVOT Observations
  23. GRB 100418A: Gemini-N redshift confirmation
  24. GRB 100413A: GMRT observation of radio afterglow
  25. GRB 100418A: Swift-XRT Refined Analysis
  26. GRB 100418A: host galaxy detection in the SDSS
  27. GRB100418A: VLT/X-shooter redshift and photometry
  28. GRB 100418A: SARA observations
  29. GRB100414A: SAO RAS optical observations
  30. GRB 100418A: GROND observations; missing author list added
  31. GRB 100418A: GROND observations
  32. GRB 100418A: Swift-BAT refined analysis
  33. GRB 100418A: Enhanced Swift-XRT position
  34. GRB 100418A: ROTSE-III Optical Limits
  35. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  36. GRB 100413A: Radio Afterglow Detection with the EVLA
  37. GRB 100414A: Suzaku WAM observation of the prompt emission
  38. GRB 100414A: Swift/UVOT Observations
  39. GRB 100414A: Gemini-N observation (correction)
  40. GRB 100414A: GROND Detection of the Optical Afterglow
  41. GRB 100414A: Gemini-N candidate and redshift
  42. GRB 100414A: Enhanced Swift-XRT position of candidate afterglow
  43. GRB 100413A: Suzaku WAM observation of the prompt emission
  44. GRB 100414A: Palomar Transient Factory Observations
  45. GRB 100413B: Swift Confirmation of Burst
  46. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  47. GRB 100413A: Swift-BAT final refined analysis
  48. GRB 100414A: IPN Localization
  49. Konus-Wind observation of GRB 100414A (correction to GCN 10597)
  50. Konus-Wind observation of GRB 100414B
  51. GRB 100415A: MAXI/GSC detection of a probable GRB
  52. GRB 100414A: Fermi GBM detection
  53. GRB100414A: Fermi LAT detection
  54. GRB 100413B : Swift detection of a burst
  55. GRB 100413A: GROND Upper limits
  56. GRB 100413A: Swift/UVOT Upper Limits
  57. Konus-Wind observation of GRB 100413A
  58. GRB 100413A: Faulkes Telescope South observations
  59. Tentative redshift of GRB100413A from X-ray data
  60. GRB 100413A: SARA upper limit
  61. GRB 100413A: Swift-XRT Refined Analysis
  62. GRB 100413A: Swift-BAT initial refined analysis
  63. GRB 100413A: Enhanced Swift-XRT position
  64. GRB 100413: xinglong TNT optical upper limit
  65. GRB 100413A: MASTER-Net optical observations
  66. GRB 100413A: Swift detection of a burst
  67. Spin down rate and inferred dipole magnetic field of the new soft gamma-ray repeater SGR 1833-0832
  68. Swift-BAT trigger 419015 is not astrophysical
  69. Trigger 419015 is probably not a GRB
  70. GRB100401A: GROND Upper Limits
  71. INTEGRAL Alert n. 5995: MASTER-Net optical observations
  72. MASTER observations on the Swift second trigger on LS V +44 17
  73. IBAS Alert n. 5996: not a GRB
  74. IBAS Alert n. 5995: not a GRB
  75. GRB 100331B: GROND Upper limits
  76. Master-Net observations on the Swift trigger on LS V +44 17
  77. GRB 100401A: Swift/UVOT Upper Limit
  78. Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
  79. GRB 100401A: Fermi GBM detection
  80. GRB 100401A Burst, possibly short, detected in ground analysis of BAT data
  81. GRB 100331B: BOOTES-3 observations
  82. GRB 100316A: R-band limit
  83. GRB 100324B: Suzaku WAM observation of the prompt emission
  84. GRB 100331B: Swift/UVOT Upper Limits
  85. GRB 100331B: Swift/XRT possible afterglow candidate
  86. Swift detection of LS V +44 17
  87. GRB 100331B: SuperAGILE Localization of a Long GRB
  88. INTEGRAL trigger 5994 (GRB100331A): Swift/XRT observations
  89. INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
  90. GRB 100331A: BOOTES-3 observations
  91. Konus-Wind observation of GRB 100324B
  92. GRB 100331A: A long GRB detected by INTEGRAL
  93. IPN triangulation of GRB100324B
  94. Konus-Wind observation of GRB 100322A
  95. Short X-ray Transient detected by MAXI/GSC
  96. Fermi GBM detection of four Solar Flares
  97. GRB 100322A: Suzaku WAM observation of the prompt emission
  98. Fermi/GBM and Swift/BAT detection of a burst from SGR 1806-20
  99. GRB 100325A: Fermi LAT detection
  100. GROND observations of GRB100316D/SN2010bh

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