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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 633173 is probably not an astrophysical source
  2. GRB 150301A: GROND Observations
  3. Trigger 633105 is likely not a GRB
  4. GRB 150301A: Fermi GBM observation
  5. GRB 150301A: Swift detection of a short burst or new SGR
  6. Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
  7. Fermi GBM Observations of Magnetar 4U 0142+61
  8. Trigger 632888: Swift detection of the magnetar 4U 0142+61
  9. GRB 150222A: Further GROND Observations
  10. GRB 150220A: Fermi GBM observation
  11. GRB 150220A: Swift-XRT observations
  12. Konus-Wind observation of GRB 150220A
  13. IPN Triangulation of GRB 150220A
  14. GRB 150220A: Swift ToO observations
  15. GRB 150222A: I-band observations from OSN
  16. GRB 150222A: Swift/UVOT Upper Limits
  17. GRB 150222A: Swift-XRT refined Analysis
  18. GRB 150222B: MAXI/GSC detection
  19. Fermi GBM Observations of SGR 1935+2154
  20. GRB 150222A: GROND optical afterglow candidate
  21. GRB 150222A: Enhanced Swift-XRT position
  22. GRB 150222A: TNG optical observations
  23. Fermi GBM trigger 150223068 is not a GRB
  24. GRB 150222A: Swift-BAT refined analysis
  25. SGR 1935+2154: Swift-BAT refined analysis
  26. GRB 150222A: Mondy optical observations
  27. GRB 150222A: Zadko observatory - Gingin optical observations
  28. GRB 150222A: MASTER early optical observations
  29. GRB 150222A: Swift detection of a burst
  30. Swift detection of an outburst from SGR 1935+2154
  31. GRB 150213B, the review of the sky area in plate archives
  32. Trigger 631946: Swift detection of H1745-203
  33. Fermi GBM trigger 150220229 is not a GRB
  34. GRB 150219A: Fermi GBM observation
  35. GRB 150219A: Swift-XRT afterglow detection
  36. Trigger 631747: Swift detection of 4U 0614+09
  37. GRB 150213B: AAO photometry
  38. GRB 150219A: Swift ToO observations
  39. GRB 150219A: A long GRB detected by INTEGRAL
  40. GRB 150213B: Enhanced Swift-XRT position
  41. GRB 150213B: P60 Observations
  42. GRB 150212A, the review of the sky area in plate archives
  43. GRB 150213B: Swift/UVOT Detection
  44. GRB 150213B: Swift-BAT refined analysis
  45. GRB 150213B: RATIR Optical and NIR Observations
  46. GRB 150213B: Swift-XRT refined Analysis
  47. GRB 150213B: AAO optical observations
  48. GRB 150213B: optical detection from the NOT
  49. GRB 150212A: Swift/UVOT Observations
  50. GRB 150213B: Tautenburg Afterglow Detection
  51. GRB 150213B: Swift detection of a burst with an optical afterglow
  52. GRB 150213A: Fermi GBM detection
  53. GRB 150212A: Swift-XRT refined Analysis
  54. GRB 150211A: ROTSE-III Upper Optical Limit
  55. GRB 150212A: RATIR Optical and NIR Observations
  56. GRB 150212A: Khureltogot optical upper limit
  57. GRB 150212A: Skynet DSO14/GORT observations
  58. GRB 150212A: Swift-BAT refined analysis
  59. GRB 150212A: MASTER optical observations
  60. GRB 150212A: No Swift/UVOT detection in initial observation
  61. GRB 150212A: P60 Afterglow Retraction
  62. GRB 150210A: Swift-XRT observations
  63. GRB 150212A: Swift-XRT afterglow detection
  64. GRB150212A: P60 Afterglow Candidate
  65. Konus-Wind observation of GRB 150211A
  66. GRB 150212A: Swift detection of a burst
  67. GRB 150211A iTelescope observation
  68. GRB 150211A: Swift/UVOT Upper Limits
  69. GRB 150210A: MASTER SN detection during LAT error box inspection
  70. GRB 150211A: Swift-BAT refined analysis
  71. GRB 150211A: KAIT Optical Upper Limit
  72. GRB 150211A: Mondy optical upper limit
  73. GRB 150211A: Swift-XRT refined Analysis
  74. GRB 150210A: Tiled Swift observations
  75. Konus-Wind observation of GRB 150210A
  76. IPN Triangulation of GRB 150210A
  77. GRB 150210A: Fermi-LAT detection
  78. GRB 150211A: RATIR Optical and NIR Observations
  79. GRB 150211A: No afterglow detection in the Swift/UVOT initial observation
  80. GRB 150211A: Swift-XRT observations
  81. GRB 150211A: Swift detection of a burst
  82. GRB 150211A: MASTER early optical observations
  83. GRB 150210A: Fermi GBM detection
  84. GRB 150101B/ Swift J123205.1-105602: Second epoch Chandra observations
  85. GRB 150204A: GROND observations
  86. GRB 150202B: Swift/XRT afterglow confirmation
  87. GRB 150204A: Swift/XRT afterglow confirmation
  88. Konus-Wind observation of GRB 150206A
  89. GRB 150206A: Swift-BAT refined analysis
  90. GRB 150203A iTelescope observation
  91. GRB 150206A: Swift/UVOT Detection
  92. GRB 150206A: Swift-XRT refined Analysis
  93. Konus-Wind observation of GRB 150202B
  94. GRB 140206B: Continued iPTF Observations
  95. GRB 150206A: VLT/X-shooter redshift
  96. GRB 150206A: GROND afterglow observations
  97. GRB 150206A: Enhanced Swift-XRT position
  98. GRB 150206B: Fermi GBM detection
  99. Trigger 630047: Swift detection of 1RXS J180408.9-342058
  100. GRB 150206B: iPTF Optical Observations

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