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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"

7447 results found.

  1. GRB 190114C: Optical follow-up from HCT
  2. Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
  3. Search for counterpart to IceCube-190124A with ANTARES
  4. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  5. GRB 190123A: Swift detection of a burst
  6. Trigger 884906: Swift detection of MAXI J1631-479
  7. GRB 190114C: Optical detection from HCT
  8. GRB 190114C: A type 1 BdHN with TeV emission
  9. INTEGRAL observation of IceCube-190104A
  10. GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart
  11. GRB 190114B: Swift detection of a burst
  12. GRB 190114A: Possible UVOT Detection
  13. GRB 190114A: Swift detection of a burst
  14. GRB 190109B: Swift detection of a burst
  15. GRB 190109A: Swift detection of a burst
  16. IceCube-190104A: Swift-XRT observations
  17. GRB 190106A: Swift detection of a burst with an optical counterpart
  18. Search for counterpart to IceCube-190104A with ANTARES
  19. IceCube-190104A - IceCube observation of a high-energy neutrino candidate event
  20. GRB 190103B: Swift detection of a burst
  21. GRB 181225A: KAIT Follow-Up Observations with Upper Limit
  22. GRB 181228A: KAIT Optical Upper Limit
  23. GRB 181228A: Swift detection of a burst
  24. GRB 181222B: Swift ToO observations
  25. GRB 181225A: Swift observations and X-ray candidate afterglow
  26. GRB 181225A: Swift ToO observations
  27. Trigger 878548: Swift detection of AX 1631.9-4752
  28. Swift Trigger 878504 is not astrophysical
  29. GRB181213A: Swift/UVOT Detection
  30. Swift Trigger 874754 is likely not an astrophysical event
  31. Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
  32. Fermi-GBM Observations During Four New GW-Detected BBH Mergers
  33. GRB 181203A: Swift detection of a burst
  34. GRB 181202A: Swift detection of a burst with an optical counterpart
  35. GRB 181201A: Swift ToO observations
  36. GRB 181126A: Swift detection of a burst
  37. GRB 181123B: Swift detection of a short burst
  38. Swift Trigger 872470 is probably not a GRB
  39. GRB 181110A: Swift detection of a burst with an optical counterpart
  40. Swift Trigger 871103 is not an astrophysical event
  41. Fermi GRB 181105.31: Global MASTER Net optical observations
  42. GRB 181103A: Swift detection of a burst
  43. Fermi-LAT Gamma-ray Observations of IceCube-181023A
  44. IceCube-181023A - IceCube observation of a high-energy neutrino candidate event
  45. GRB 181023A: KAIT Optical Upper Limit
  46. GRB 181023A: Swift detection of a burst
  47. GRB 181022A: Swift detection of a burst
  48. GRB 181020A: Swift detection of a burst with an optical counterpart
  49. IceCube-181014A - IceCube observation of a high-energy neutrino candidate event
  50. GRB 181013A: Swift detection of a probable burst
  51. GRB 181010A: MASTER-Argentina OT detection
  52. GRB 181010A: Swift detection of a burst with an optical counterpart
  53. GRB 181002A: Swift detection of a burst
  54. GRB 180930A: KAIT Optical Upper Limit
  55. GRB 180930A: Swift detection of a burst
  56. GRB 180925A: Swift detection of a burst
  57. GRB 180924A: Swift detection of a burst
  58. Swift Trigger 863053 is not an astrophysical event
  59. GRB 180923A: MASTER inspection MAXI/GSC error box
  60. GRB 180914B: KAIT Optical Afterglow Candidate
  61. GRB 180914B: Tiled Swift observations
  62. GRB 180914A: MASTER automatic inspection
  63. GRB 180914A: Tiled Swift observations
  64. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  65. INTEGRAL observation of IceCube-180908A
  66. Search for counterpart to IceCube-180908A with ANTARES
  67. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  68. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  69. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  70. GRB 180905A: Swift detection of a burst
  71. GRB 180904A: NOT optical observations, candidate host galaxy
  72. GRB 180904A: Swift detection of a burst
  73. GRB 180829A: Tiled Swift observations
  74. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  75. GRB 180818B: TSHAO optical upper limit
  76. GRB 180823A: Swift detection of a burst
  77. GRB 180821A: iTelescope counterpart is not the afterglow
  78. GRB 180818B: 1.5m OSN optical afterglow candidate
  79. GRB 180821A: Swift detection of a burst
  80. GRB 180818B: Swift detection of a burst
  81. GRB 180818A: Swift detection of a burst
  82. GRB 180809A: further Swift/XRT observations
  83. Correction: Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  84. LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays
  85. Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  86. GRB 180812A: Swift detection of a burst
  87. Swift Trigger 852625: a possible GRB
  88. GRB 180809B: Swift detection of a burst with an optical afterglow
  89. GRB 180809A: Tiled Swift observations
  90. GRB 180806A: NOT optical observations
  91. GRB 180806A: Swift ToO observations
  92. GRB 180805B: Swift detection of a burst
  93. GRB 180805A: Swift detection of a burst
  94. GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
  95. GRB 180728B: MASTER optical observations short GRB IPN error box
  96. GRB 180727A: Swift detection of a burst
  97. GRB 180721A: KAIT Optical Upper Limit
  98. GRB 180720B: Testing the universality of the newly born neutron star in BdHNe
  99. GRB 180722A: Tiled Swift observations
  100. ANTARES neutrino Alert180713.02: MASTER optical observation

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