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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"

6405 results found.

  1. GRB 210619B: SAO RAS optical observations
  2. GRB 210619B: GIT optical follow-up and confirmation of jet-break
  3. GRB 210619B: Fermi GBM detection
  4. GRB 210619B: Fermi-LAT detection
  5. GRB 210619B: Swift-XRT refined Analysis
  6. GRB 210618A: Fermi GBM observation
  7. GRB 210618A: Swift-XRT observations
  8. GRB 201008A: Fermi GBM observation
  9. GRB 210323B: Fermi GBM observation
  10. Fermi GRB 210615A: Global MASTER-Net observations report
  11. Swift ToO Observations of HAWC transient J0020+3108
  12. GRB 210605B: Swift-XRT afterglow detection
  13. GRB 210610A: Fermi GBM observations
  14. GRB 210610B: Further SAO RAS optical observations
  15. GRB 210610A: SAO RAS optical observations
  16. GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
  17. GRB 210421B: Fermi GBM detection
  18. GRB 201228B: Fermi GBM observation
  19. GRB 210610A: CAHA 2.2m observations and light-curve behavior
  20. GRB 210606A: Fermi GBM detection
  21. GRB 210605B: Fermi GBM detection
  22. GRB 210610B: Swift-XRT refined Analysis
  23. GRB 210610B: Fermi GBM detection
  24. Konus-Wind detection of GRB 210610A
  25. Konus-Wind detection of GRB 210610B
  26. GRB 210610A: Swift-XRT refined Analysis
  27. GRB 210610B: iTelescope optical afterglow observations
  28. GRB 210606A: Swift-XRT afterglow detection
  29. GRB 210610A: GIT optical detection
  30. Fermi-LAT Gamma-ray Observations of IceCube-210608A
  31. GRB 210606B: Fermi GBM detection
  32. GRB 210605B: Swift-XRT observations
  33. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  34. Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
  35. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  36. GRB 210528A: Fermi GBM detection
  37. GRB 210527A: GIT optical upper limit
  38. GRB 210527A: Swift-XRT refined Analysis
  39. GRB 210520A: Swift-XRT observations
  40. GRB210413B: further Swift-XRT observations
  41. GRB 210520A: Fermi GBM detection
  42. GRB 210520A: Fermi-LAT detection
  43. Fermi GBM observation of a bright burst from magneta
  44. Fermi-LAT Gamma-ray Observations of IceCube-210516A
  45. GRB 210517A: Swift-XRT refined Analysis
  46. IceCube-210516A: No significant detection in HAWC
  47. GRB 210515C: Swift-XRT refined Analysis
  48. GRB 210514A: Swift-XRT refined Analysis
  49. GRB 210514A: update on the BAT trigger time and burst duration
  50. GRB 210511B: Fermi GBM observation
  51. Fermi-LAT Gamma-ray Observations of IceCube-210510A
  52. GRB 210509A: Swift-XRT refined Analysis
  53. Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
  54. GRB 210506A: Swift-XRT observations
  55. Alert from the HAWC Burst Monitor HAWC-210507A
  56. GRB 210504A: Swift-XRT refined Analysis
  57. GRB 210504A: MITSuME Akeno optical upper limits
  58. GRB 210413B: Swift/UVOT Observations
  59. GRB 210323B: Swift-XRT observations
  60. Swift Trigger 1045571 is not a GRB
  61. GRB 210422B: Fermi GBM Final Localization
  62. GRB 210421B: Swift-XRT observations
  63. GRB 210420B: Swift-XRT refined Analysis
  64. GRB 210421A: Swift-XRT refined Analysis
  65. GRB 210419A: Swift-XRT refined Analysis
  66. GRB 210413B: Swift-XRT observations
  67. GRB 210410A: A twin of short GRB 090510 with complementary observations
  68. GRB 210411C: Swift-XRT refined Analysis
  69. GRB 210410A: Swift-XRT refined Analysis
  70. GRB 210410A: Fermi GBM detection
  71. GRB 210406A: Swift-XRT observations
  72. GRB 210410A: Fermi-LAT detection
  73. GRB 210406B: Fermi GBM detection
  74. GRB 210406A: Fermi GBM detection
  75. GRB 210402A: Fermi GBM detection
  76. GRB 210402A: Swift-XRT refined Analysis
  77. GRB 210323A: Fermi GBM detection
  78. GRB 210323A: Swift-XRT refined Analysis
  79. GRB 210321A: Swift-XRT refined Analysis
  80. GRB 210318A: Swift-XRT refined Analysis
  81. GRB 210318B: Fermi GBM detection
  82. GRB210318B: Swift detection of a burst
  83. GRB 210226A: GIT optical upper limit
  84. GRB 210306A: HCT optical upper limit
  85. GRB 210306B: Fermi GBM detection
  86. GRB 210305A: Fermi GBM observation
  87. GRB 210308A: Fermi GBM detection
  88. GRB 210305A: Swift-XRT refined Analysis
  89. GRB 210307A: Swift-XRT refined Analysis
  90. GRB 210306A: Swift-XRT refined Analysis
  91. GRB 210306A: Fermi GBM observation
  92. GRB 210306A: iTelescope T24 optical observations
  93. GRB 210306A: Fermi-LAT detection
  94. GRB 210306A: iTelescope optical afterglow observations
  95. GRB 210217A: 3.6m DOT optical observations
  96. GRB 210226A: Fermi GBM detection
  97. GRB 210226A: Swift-XRT refined Analysis
  98. GRB 210218A: Swift-XRT confirmation of afterglow
  99. GRB 210222B: Swift-XRT refined Analysis
  100. GRB 210218A: Swift/UVOT observations

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