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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"

4055 results found.

  1. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  2. GRB 231106A: TESS identification of candidate optical counterpart
  3. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  4. LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
  5. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  6. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  7. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  8. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  10. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  11. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  12. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  13. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S231112ag: Retraction of GW compact binary merger candidate
  16. LIGO/Virgo/KAGRA S231110g: Updated Sky localization
  17. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo/KAGRA S231108u: Updated Sky localization
  19. LIGO/Virgo/KAGRA O4 Landscape
  20. LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  22. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  23. LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
  24. LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
  25. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  26. LIGO/Virgo/KAGRA S231102w: Updated Sky localization
  27. LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
  29. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  30. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  31. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  32. LIGO/Virgo/KAGRA S231030av: Retraction of GW compact binary merger candidate
  33. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  34. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S231028bg: Updated Sky localization
  38. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S231025a: two counterpart neutrino candidates from IceCube neutrino searches
  42. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  44. LIGO/Virgo/KAGRA S231020bw: Updated Sky localization
  45. LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification
  46. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  47. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  49. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S231018cb: One counterpart neutrino candidate event from an IceCube neutrino search
  51. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  52. IceCube-231014A: Upper limits from a search for additional neutrino events in IceCube
  53. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  54. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  56. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S231008ap: Updated Sky localization
  58. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  59. IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
  60. LIGO/Virgo/KAGRA S231005ah: Updated Sky localization
  61. LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo/KAGRA S231005j: Updated Sky localization
  63. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  64. Update of IceCube-231004A - Corrected direciton
  65. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  66. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  67. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  68. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  69. LIGO/Virgo/KAGRA S230930al: Updated Sky localization
  70. LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
  71. LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S230927be: Updated Sky localization
  75. LIGO/Virgo/KAGRA S230927l: Updated Sky localization
  76. LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  78. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  79. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  80. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  81. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  82. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  83. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  84. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  85. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  87. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  88. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  91. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  92. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  93. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  94. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  96. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  97. LIGO/Virgo/KAGRA S230918aq: Retraction of GW compact binary merger candidate
  98. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  99. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  100. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO

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