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

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