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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 J0045.2+4151: analysis of XMM-Newton archival data
  2. Further UVOT Observations of Swift J0045.2+4151
  3. Fermi GBM trigger 150305751 is not a GRB
  4. GRB 150301C: VLA Observations
  5. Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622)
  6. BAT trigger 633105 (GRB 150301C): NOT r-band upper limit
  7. GRB 150302A: BOOTES-2/TELMA upper limit
  8. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  9. GRB 150302A: Mondy optical upper limit
  10. GRB 150302A, Swift-BAT refined analysis
  11. GRB 150302A: Swift/UVOT Upper Limits
  12. GRB 150302A: MITSuME Okayama upper limits
  13. GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
  14. GRB 150302A: Swift-XRT refined Analysis
  15. GRB 150302A: Enhanced Swift-XRT position
  16. GRB 150301B: Swift-XRT refined Analysis
  17. GRB 150220A: further Swift-XRT observations
  18. GRB 150301B: Swift/UVOT Observations
  19. GRB 150301B: LCOGT-Sutherland observations
  20. GRB 150302A: KAIT Optical Upper Limit
  21. GRB 150302A: UVOT Observations
  22. GRB 150302A: NOT afterglow candidate
  23. GRB 150302A: Swift detection of a burst
  24. GRB 150301B: Fermi GBM detection
  25. GRB 150301B: Swift-BAT refined analysis
  26. GRB 150301B: X-shooter spectroscopy
  27. GRB 150301B: GROND afterglow observations
  28. GRB 150301A: Swift/UVOT Upper Limits
  29. GRB 150301B: Enhanced Swift-XRT position
  30. GRB 150301A: Swift-BAT refined analysis
  31. GRB 150301B: MASTER early OT detection
  32. GRB 150301A: Swift-XRT refined Analysis
  33. GRB 150301C : (Swift trigger 633105) Swift observations
  34. GRB 150301B: Swift detection of a burst with an optical afterglow
  35. Swift Trigger 633173 is probably not an astrophysical source
  36. GRB 150301A: GROND Observations
  37. Trigger 633105 is likely not a GRB
  38. GRB 150301A: Fermi GBM observation
  39. GRB 150301A: Swift detection of a short burst or new SGR
  40. Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
  41. Fermi GBM Observations of Magnetar 4U 0142+61
  42. Trigger 632888: Swift detection of the magnetar 4U 0142+61
  43. GRB 150222A: Further GROND Observations
  44. GRB 150220A: Fermi GBM observation
  45. GRB 150220A: Swift-XRT observations
  46. Konus-Wind observation of GRB 150220A
  47. IPN Triangulation of GRB 150220A
  48. GRB 150220A: Swift ToO observations
  49. GRB 150222A: I-band observations from OSN
  50. GRB 150222A: Swift/UVOT Upper Limits
  51. GRB 150222A: Swift-XRT refined Analysis
  52. GRB 150222B: MAXI/GSC detection
  53. Fermi GBM Observations of SGR 1935+2154
  54. GRB 150222A: GROND optical afterglow candidate
  55. GRB 150222A: Enhanced Swift-XRT position
  56. GRB 150222A: TNG optical observations
  57. Fermi GBM trigger 150223068 is not a GRB
  58. GRB 150222A: Swift-BAT refined analysis
  59. SGR 1935+2154: Swift-BAT refined analysis
  60. GRB 150222A: Mondy optical observations
  61. GRB 150222A: Zadko observatory - Gingin optical observations
  62. GRB 150222A: MASTER early optical observations
  63. GRB 150222A: Swift detection of a burst
  64. Swift detection of an outburst from SGR 1935+2154
  65. GRB 150213B, the review of the sky area in plate archives
  66. Trigger 631946: Swift detection of H1745-203
  67. Fermi GBM trigger 150220229 is not a GRB
  68. GRB 150219A: Fermi GBM observation
  69. GRB 150219A: Swift-XRT afterglow detection
  70. Trigger 631747: Swift detection of 4U 0614+09
  71. GRB 150213B: AAO photometry
  72. GRB 150219A: Swift ToO observations
  73. GRB 150219A: A long GRB detected by INTEGRAL
  74. GRB 150213B: Enhanced Swift-XRT position
  75. GRB 150213B: P60 Observations
  76. GRB 150212A, the review of the sky area in plate archives
  77. GRB 150213B: Swift/UVOT Detection
  78. GRB 150213B: Swift-BAT refined analysis
  79. GRB 150213B: RATIR Optical and NIR Observations
  80. GRB 150213B: Swift-XRT refined Analysis
  81. GRB 150213B: AAO optical observations
  82. GRB 150213B: optical detection from the NOT
  83. GRB 150212A: Swift/UVOT Observations
  84. GRB 150213B: Tautenburg Afterglow Detection
  85. GRB 150213B: Swift detection of a burst with an optical afterglow
  86. GRB 150213A: Fermi GBM detection
  87. GRB 150212A: Swift-XRT refined Analysis
  88. GRB 150211A: ROTSE-III Upper Optical Limit
  89. GRB 150212A: RATIR Optical and NIR Observations
  90. GRB 150212A: Khureltogot optical upper limit
  91. GRB 150212A: Skynet DSO14/GORT observations
  92. GRB 150212A: Swift-BAT refined analysis
  93. GRB 150212A: MASTER optical observations
  94. GRB 150212A: No Swift/UVOT detection in initial observation
  95. GRB 150212A: P60 Afterglow Retraction
  96. GRB 150210A: Swift-XRT observations
  97. GRB 150212A: Swift-XRT afterglow detection
  98. GRB150212A: P60 Afterglow Candidate
  99. Konus-Wind observation of GRB 150211A
  100. GRB 150212A: Swift detection of a burst

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