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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"

7450 results found.

  1. GRB 190129B: Tiled Swift observations
  2. INTEGRAL observation of IceCube-190124A
  3. Trigger 886266: Another Swift trigger on MAXI J1348-630
  4. GRB 190114C: Optical follow-up from HCT
  5. Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
  6. Search for counterpart to IceCube-190124A with ANTARES
  7. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  8. GRB 190123A: Swift detection of a burst
  9. Trigger 884906: Swift detection of MAXI J1631-479
  10. GRB 190114C: Optical detection from HCT
  11. GRB 190114C: A type 1 BdHN with TeV emission
  12. INTEGRAL observation of IceCube-190104A
  13. GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart
  14. GRB 190114B: Swift detection of a burst
  15. GRB 190114A: Possible UVOT Detection
  16. GRB 190114A: Swift detection of a burst
  17. GRB 190109B: Swift detection of a burst
  18. GRB 190109A: Swift detection of a burst
  19. IceCube-190104A: Swift-XRT observations
  20. GRB 190106A: Swift detection of a burst with an optical counterpart
  21. Search for counterpart to IceCube-190104A with ANTARES
  22. IceCube-190104A - IceCube observation of a high-energy neutrino candidate event
  23. GRB 190103B: Swift detection of a burst
  24. GRB 181225A: KAIT Follow-Up Observations with Upper Limit
  25. GRB 181228A: KAIT Optical Upper Limit
  26. GRB 181228A: Swift detection of a burst
  27. GRB 181222B: Swift ToO observations
  28. GRB 181225A: Swift observations and X-ray candidate afterglow
  29. GRB 181225A: Swift ToO observations
  30. Trigger 878548: Swift detection of AX 1631.9-4752
  31. Swift Trigger 878504 is not astrophysical
  32. GRB181213A: Swift/UVOT Detection
  33. Swift Trigger 874754 is likely not an astrophysical event
  34. Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
  35. Fermi-GBM Observations During Four New GW-Detected BBH Mergers
  36. GRB 181203A: Swift detection of a burst
  37. GRB 181202A: Swift detection of a burst with an optical counterpart
  38. GRB 181201A: Swift ToO observations
  39. GRB 181126A: Swift detection of a burst
  40. GRB 181123B: Swift detection of a short burst
  41. Swift Trigger 872470 is probably not a GRB
  42. GRB 181110A: Swift detection of a burst with an optical counterpart
  43. Swift Trigger 871103 is not an astrophysical event
  44. Fermi GRB 181105.31: Global MASTER Net optical observations
  45. GRB 181103A: Swift detection of a burst
  46. Fermi-LAT Gamma-ray Observations of IceCube-181023A
  47. IceCube-181023A - IceCube observation of a high-energy neutrino candidate event
  48. GRB 181023A: KAIT Optical Upper Limit
  49. GRB 181023A: Swift detection of a burst
  50. GRB 181022A: Swift detection of a burst
  51. GRB 181020A: Swift detection of a burst with an optical counterpart
  52. IceCube-181014A - IceCube observation of a high-energy neutrino candidate event
  53. GRB 181013A: Swift detection of a probable burst
  54. GRB 181010A: MASTER-Argentina OT detection
  55. GRB 181010A: Swift detection of a burst with an optical counterpart
  56. GRB 181002A: Swift detection of a burst
  57. GRB 180930A: KAIT Optical Upper Limit
  58. GRB 180930A: Swift detection of a burst
  59. GRB 180925A: Swift detection of a burst
  60. GRB 180924A: Swift detection of a burst
  61. Swift Trigger 863053 is not an astrophysical event
  62. GRB 180923A: MASTER inspection MAXI/GSC error box
  63. GRB 180914B: KAIT Optical Afterglow Candidate
  64. GRB 180914B: Tiled Swift observations
  65. GRB 180914A: MASTER automatic inspection
  66. GRB 180914A: Tiled Swift observations
  67. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  68. INTEGRAL observation of IceCube-180908A
  69. Search for counterpart to IceCube-180908A with ANTARES
  70. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  71. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  72. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  73. GRB 180905A: Swift detection of a burst
  74. GRB 180904A: NOT optical observations, candidate host galaxy
  75. GRB 180904A: Swift detection of a burst
  76. GRB 180829A: Tiled Swift observations
  77. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  78. GRB 180818B: TSHAO optical upper limit
  79. GRB 180823A: Swift detection of a burst
  80. GRB 180821A: iTelescope counterpart is not the afterglow
  81. GRB 180818B: 1.5m OSN optical afterglow candidate
  82. GRB 180821A: Swift detection of a burst
  83. GRB 180818B: Swift detection of a burst
  84. GRB 180818A: Swift detection of a burst
  85. GRB 180809A: further Swift/XRT observations
  86. Correction: Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  87. LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays
  88. Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  89. GRB 180812A: Swift detection of a burst
  90. Swift Trigger 852625: a possible GRB
  91. GRB 180809B: Swift detection of a burst with an optical afterglow
  92. GRB 180809A: Tiled Swift observations
  93. GRB 180806A: NOT optical observations
  94. GRB 180806A: Swift ToO observations
  95. GRB 180805B: Swift detection of a burst
  96. GRB 180805A: Swift detection of a burst
  97. GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
  98. GRB 180728B: MASTER optical observations short GRB IPN error box
  99. GRB 180727A: Swift detection of a burst
  100. GRB 180721A: KAIT Optical Upper Limit

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