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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"

3036 results found.

  1. GRB 210826A: further Swift-XRT observations
  2. Fermi trigger No 652927551: Global MASTER-Net observations report
  3. GRB 210905A: Swift-XRT refined Analysis
  4. GRB 210901A: Swift-XRT refined Analysis
  5. GRB 210827A: further Swift-XRT observations
  6. GRB 210827A: Swift-XRT observations
  7. GRB 210826A: Swift-XRT observations
  8. GRB 210826A: Fermi-LAT detection
  9. GRB 210824A: Swift-XRT refined Analysis
  10. GRB 210822A: Swift-XRT refined Analysis
  11. GRB 210820A: Swift-XRT refined Analysis
  12. GRB 210818A: Swift-XRT refined Analysis
  13. GRB 210802A: Further Swift/XRT observation and afterglow confirmation
  14. GRB 210807C: Swift-XRT refined Analysis
  15. GRB 210807A: Swift-XRT refined Analysis
  16. GRB 210802A: Swift-XRT afterglow detection
  17. GRB 210731A: Swift-XRT refined Analysis
  18. GRB 210726A: Chandra detection of the X-ray afterglow
  19. GRB 210730A: Swift-XRT refined Analysis
  20. GRB 210726A: Swift-XRT refined Analysis
  21. GRB 210725B: Swift-XRT refined Analysis
  22. GRB 210725A: Swift-XRT refined Analysis
  23. GRB 210724A: Swift-XRT refined Analysis
  24. GRB 210723A: Swift-XRT refined Analysis
  25. GRB 210722A: Swift-XRT refined Analysis
  26. GRB 210712A: Swift-XRT refined Analysis
  27. GRB 210706A: Swift/XRT afterglow confirmation
  28. GRB 210708A: Swift-XRT refined Analysis
  29. GRB 210706A: Swift-XRT afterglow detection
  30. GRB 210704A: Swift-XRT afterglow detection
  31. GRB 210702A: Swift-XRT refined Analysis
  32. GRB 210626A: Swift/XRT afterglow confirmation
  33. GRB 210626A: Swift-XRT afterglow detection
  34. GRB 210622A: Swift-XRT observations
  35. GRB 210618A: Swift-XRT afterglow detection
  36. GRB 210619B: Swift-XRT refined Analysis
  37. GRB 210618A: Swift-XRT observations
  38. Swift ToO Observations of HAWC transient J0020+3108
  39. GRB 210605B: Swift-XRT afterglow detection
  40. GRB 210610B: Swift-XRT refined Analysis
  41. GRB 210610A: Swift-XRT refined Analysis
  42. GRB 210606A: Swift-XRT afterglow detection
  43. GRB 210605B: Swift-XRT observations
  44. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  45. Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
  46. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  47. GRB 210527A: Swift-XRT refined Analysis
  48. GRB 210520A: Swift-XRT observations
  49. GRB210413B: further Swift-XRT observations
  50. GRB 210517A: Swift-XRT refined Analysis
  51. GRB 210514A: Swift/UVOT Upper Limits
  52. GRB 210515C: Swift-XRT refined Analysis
  53. GRB 210514A: Swift-XRT refined Analysis
  54. GRB 210514A: update on the BAT trigger time and burst duration
  55. GRB 210509A: Swift-XRT refined Analysis
  56. GRB 210506A: Swift-XRT observations
  57. GRB 210504A: Swift-XRT refined Analysis
  58. GRB 210413B: Swift/UVOT Observations
  59. GRB 210323B: Swift-XRT observations
  60. Swift Trigger 1045571 is not a GRB
  61. GRB 210421B: Swift-XRT observations
  62. GRB 210420B: Swift-XRT refined Analysis
  63. GRB 210421A: Swift-XRT refined Analysis
  64. GRB 210419A: Swift-XRT refined Analysis
  65. GRB 210413B: Swift-XRT observations
  66. GRB 210411C: Swift-XRT refined Analysis
  67. GRB 210410A: Swift-XRT refined Analysis
  68. GRB 210406A: Swift-XRT observations
  69. GRB 210402A: Swift-XRT refined Analysis
  70. GRB 210323A: Swift-XRT refined Analysis
  71. GRB 210321A: Swift-XRT refined Analysis
  72. GRB 210318A: Swift-XRT refined Analysis
  73. GRB210318B: Swift detection of a burst
  74. GRB 171205A: Continued ATCA observations
  75. GRB 210305A: Swift-XRT refined Analysis
  76. GRB 210307A: Swift-XRT refined Analysis
  77. GRB 210306A: Swift-XRT refined Analysis
  78. GRB 210226A: Swift-XRT refined Analysis
  79. GRB 210218A: Swift-XRT confirmation of afterglow
  80. GRB 210222B: Swift-XRT refined Analysis
  81. GRB 210218A: Swift/UVOT observations
  82. GRB 210218A: Swift-XRT observations
  83. GRB 210217A: Swift-XRT refined Analysis
  84. GRB 210212A: Swift-XRT refined Analysis
  85. GRB 210204A: observations with the 3.6m Devasthal Optical Telescope and possible jet break
  86. GRB 210211A: Swift-XRT refined Analysis
  87. Swift-XRT observations of IceCube-210210A
  88. GRB 210210A: Swift-XRT refined Analysis
  89. GRB 210209A: Swift-XRT refined Analysis
  90. GRB 210207B: Swift-XRT refined Analysis
  91. GRB 210204A / ZTF21aagwbjr: Swift-XRT observations
  92. GRB 210205A: Swift-XRT refined Analysis
  93. Continued Chandra observations of GW170817 at ~3.3 years since merger
  94. GRB 140330A: Swift-XRT refined Analysis
  95. GRB 140320B: Swift-XRT refined Analysis
  96. GRB 140402A: Swift-XRT refined Analysis
  97. GRB 140104B: Swift-XRT refined Analysis
  98. GRB 201221D: near-infrared observation with LBT
  99. GRB 210112A: Swift-XRT refined Analysis
  100. Correction to GCN 29278: GRB 201216C XRT refined analysis

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