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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 100413A: MASTER-Net optical observations
  2. GRB 100413A: Swift detection of a burst
  3. Spin down rate and inferred dipole magnetic field of the new soft gamma-ray repeater SGR 1833-0832
  4. Swift-BAT trigger 419015 is not astrophysical
  5. Trigger 419015 is probably not a GRB
  6. GRB100401A: GROND Upper Limits
  7. INTEGRAL Alert n. 5995: MASTER-Net optical observations
  8. MASTER observations on the Swift second trigger on LS V +44 17
  9. IBAS Alert n. 5996: not a GRB
  10. IBAS Alert n. 5995: not a GRB
  11. GRB 100331B: GROND Upper limits
  12. Master-Net observations on the Swift trigger on LS V +44 17
  13. GRB 100401A: Swift/UVOT Upper Limit
  14. Swift/BAT trigger 417974 (GRB100401A): Swift/XRT observations
  15. GRB 100401A: Fermi GBM detection
  16. GRB 100401A Burst, possibly short, detected in ground analysis of BAT data
  17. GRB 100331B: BOOTES-3 observations
  18. GRB 100316A: R-band limit
  19. GRB 100324B: Suzaku WAM observation of the prompt emission
  20. GRB 100331B: Swift/UVOT Upper Limits
  21. GRB 100331B: Swift/XRT possible afterglow candidate
  22. Swift detection of LS V +44 17
  23. GRB 100331B: SuperAGILE Localization of a Long GRB
  24. INTEGRAL trigger 5994 (GRB100331A): Swift/XRT observations
  25. INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
  26. GRB 100331A: BOOTES-3 observations
  27. Konus-Wind observation of GRB 100324B
  28. GRB 100331A: A long GRB detected by INTEGRAL
  29. IPN triangulation of GRB100324B
  30. Konus-Wind observation of GRB 100322A
  31. Short X-ray Transient detected by MAXI/GSC
  32. Fermi GBM detection of four Solar Flares
  33. GRB 100322A: Suzaku WAM observation of the prompt emission
  34. Fermi/GBM and Swift/BAT detection of a burst from SGR 1806-20
  35. GRB 100325A: Fermi LAT detection
  36. GROND observations of GRB100316D/SN2010bh
  37. GRB 100325A: Fermi GBM detection
  38. GRB 100324A: GROND observations
  39. GRB 100324A found in ground analysis of BAT data
  40. Emerging Supernova in the Afterglow of GRB 100316D
  41. GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
  42. GRB 100316D: Spectroscopic Discovery of a Supernova from Magellan
  43. SGR 1833-0832: Swift/UVOT Upper Limits
  44. GRB 100322A: Fermi GBM detection
  45. SGR 1833-0832: Archival Chandra Observations
  46. SGR 1833-0832 is pulsed at 7.56 seconds
  47. SGR 1833-0832 is pulsed at 7.56 seconds
  48. Possible pulsation period in SGR 1833-0832
  49. Discovery of the Spin Period of SGR 1833-0832
  50. GRB 100316D: ATCA radio observations
  51. GRB 100319A: correction to GCN 10527
  52. Probable SGR 1833-0832: Swift-XRT refined analysis
  53. Probable SGR 1833-0832: Enhanced Swift-XRT position
  54. Swift-XRT refined position of the probable new SGR 1833-0832
  55. Swift-BAT refined analysis of the probable new SGR 1833-0832
  56. GRB 100219A: MASTER-Net optical alert observations
  57. GRB 100319A: Swift detection of a burst; possible SGR
  58. GRB 100316D: Possible Supernova
  59. GRB 100316D: Pre-burst emission measured by BAT
  60. GRB 100316D: Further Gemini observations
  61. GRB 100219A: optical upper limit
  62. GRB 100316A: optical observations in CrAO
  63. GRB 100316D: Swift/UVOT Observations
  64. GRB 100316D: Swift XRT enhanced position and further refined analysis
  65. GRB 100316B: Swift-XRT refined analysis
  66. Tentative redshift of GRB100316D from X-ray data
  67. GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
  68. Trigger 416226 is probably not a GRB
  69. GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
  70. GRB 100316D: Gemini/GMOS and VLT/X-shooter observations
  71. GRB 100316D: VLT/X-shooter observations
  72. GRB 100316D: Swift-BAT refined analysis
  73. GRB100316C: Swift/UVOT Upper Limits
  74. GRB 100316C: Swift-BAT refined analysis
  75. GRB 100316B: Swift/UVOT observations
  76. GRB 100316C: Swift-XRT team refined analysis
  77. GRB 100316C: Enhanced Swift-XRT position
  78. GRB 100316D: Swift XRT refined analysis
  79. GRB 100316A: TAROT Calern observatory optical observations
  80. GRB 100316A: Swift-XRT refined analysis
  81. GRB 100316B: Enhanced Swift-XRT position
  82. GRB 100316A: Swift-BAT refined analysis
  83. GRB 100316B: Swift-BAT refined analysis
  84. GRB100316A: Swift/UVOT Upper Limits
  85. Trigger 416140 is almost certainly not a GRB
  86. GRB 100316C: BOOTES-3 observations
  87. GRB 100316D: Swift detection of a burst
  88. GRB 100316B: VLT/X-shooter redshift
  89. GRB 100316B: Skynet/PROMPT Observations of Fading
  90. GRB 100316B: GROND Detection of the Optical/NIR Afterglow Candidate
  91. XRF 100315A: MAXI/GSC detection of a short X-ray transient
  92. GRB 100316C: Swift detection of a burst
  93. GRB 100316A: Enhanced Swift-XRT position
  94. GRB 100316B: Swift detection of a burst with optical counterpart
  95. GRB 100316 optical candidate from 1.23m CAHA telescope
  96. GRB 100316 optical candidate from 1.23m CAHA telescope
  97. GRB 100316A: Swift/UVOT Observations
  98. GRB 100316A: Swift-XRT detection
  99. GRB 100316A: Swift detection of a burst
  100. IBAS Alert 5992 is not a GRB, but XTE J1855-026

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