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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  2. GRB 230827B: 10.4m GTC spectroscopic redshift
  3. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  4. LIGO/Virgo/KAGRA S230930al: Updated Sky localization
  5. LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
  6. LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
  7. GRB 230930A: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
  9. NuEm-230927A: Swift-XRT follow-up
  10. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  11. AT2023sva / GRB230916B: GIT observations of the afterglow
  12. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  13. LIGO/Virgo/KAGRA S230927be: Updated Sky localization
  14. LIGO/Virgo/KAGRA S230927l: Updated Sky localization
  15. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230927A
  16. LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
  17. Swift Triggers 1192745 and 1192747 are not astrophysical events
  18. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  19. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  20. Swift Triggers 1192735 and 1192737 are not astrophysical events
  21. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  22. Konus-Wind detection of GRB 230919A
  23. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  25. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  26. Fermi Gamma-ray Burst Monitor trigger 717299390/230925076 is not a GRB
  27. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  28. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  29. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  30. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  31. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  32. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  33. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  34. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  37. GRB 230921A: Fermi GBM Final Real-time Localization
  38. GRB 230918B: VLT/X-shooter classification of AT 2023tbf (GOTO23aky) as a dwarf nova
  39. IPN triangulation of GRB 230919A (short)
  40. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  41. GRB 230919A: Fermi GBM Observation
  42. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  43. Fermi GBM Statement for Trigger 716527670/230916144
  44. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  45. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  46. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  47. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  48. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  49. GRB 230919A: AstroSat CZTI detection
  50. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  51. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  52. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  53. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  54. GRB 230919A: Fermi GBM Final Real-time Localization
  55. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  56. Detection of self-absorbed radio emission from GRB 230812B with the JVLA + uGMRT
  57. GRB 230918B: Fermi GBM Final Real-time Localization
  58. GRB 230918A (short): Glowbug gamma-ray detection
  59. GRB 230916B: Glowbug gamma-ray detection
  60. AT 2023sva: NOT observations of the ZTF candidate afterglow
  61. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  62. GRB 230915A: Fermi GBM observation
  63. LIGO/Virgo/KAGRA S230918aq: Retraction of GW compact binary merger candidate
  64. GRB 230812B: Radio observations with the uGMRT
  65. GRB 230918A: Fermi GBM Final Real-time Localization
  66. GRB 230917A: AstroSat CZTI detection
  67. Swift Triggers 1192480, 1192481, 1192482 and 1192483 are not astrophysical events
  68. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  69. GRB 230915B: Glowbug gamma-ray detection
  70. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  71. GRB 230911A: Fermi GBM Observation
  72. Swift GRB230916.18: Global MASTER-Net observations report
  73. Fermi trigger No 716572242: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  75. Fermi trigger No 716544961: Global MASTER-Net observations report
  76. Fermi-LAT gamma-ray observations of IceCube-230914A
  77. GRB 230915A: Swift/BAT-GUANO detection of a burst
  78. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  79. GRB 230911D: GRBAlpha detection
  80. Swift GRB230916.19: Global MASTER-Net observations report
  81. Swift GRB230916.18: Global MASTER-Net observations report
  82. Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
  83. Swift GRB230916.13: Global MASTER-Net observations report
  84. Swift GRB230916.12: Global MASTER-Net observations report
  85. Swift GRB230916.11: Global MASTER-Net observations report
  86. Swift Trigger 1192233 is not a GRB
  87. GRB 230906A: optical counterpart
  88. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  89. GRB 230911A: Swift-XRT afterglow detection
  90. Fermi trigger No 716449174: Global MASTER-Net observations report
  91. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  92. IceCube Alert 230914.22: Global MASTER-Net observations report
  93. Swift Trigger 1192088 is not an astrophysical event
  94. Fermi trigger No 716419312: Global MASTER-Net observations report
  95. GRB 230913A: Glowbug gamma-ray detection
  96. LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
  97. GRB 230812B: Bad Time Intervals for Fermi GBM data
  98. IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
  99. LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
  100. Swift Trigger 1191994 is not an astrophysical event

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