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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 S230731an: Upper limits from Swift/BAT-GUANO
  2. GRB 230723A: SPT-3G millimeter-band transient event inconsistent with IPN position
  3. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  4. LIGO/Virgo/KAGRA S230731an: not observable by Fermi-GBM
  5. LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
  6. GRB 230731A: Fermi GBM Final Real-time Localization
  7. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S230729z: Updated Sky localization
  10. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  11. Fermi trigger No 712390645: Global MASTER-Net observations report
  12. GRB 230728A: Swift-BAT refined analysis
  13. Fermi-LAT gamma-ray observations of IceCube-230727A
  14. GRB 230723B: Swift-BAT refined analysis
  15. Fermi trigger No 712306969: Global MASTER-Net observations report
  16. GRB 230723B: MITSuME Ishigaki optical observation
  17. IceCube-230727A: No candidates from the Zwicky Transient Facility
  18. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  19. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  20. GRB 230728A: BOOTES-1 optical upper limit
  21. GRB 230728A: Fermi GBM Observation
  22. GRB 230728A: LCOGT Optical Upper Limit
  23. GRB 230728A: Swift/UVOT Upper Limits
  24. GRB 230728A: Swift-XRT refined Analysis
  25. GRB 230728A: Enhanced Swift-XRT position
  26. GRB 230728A: NOT optical observations and possible host galaxy
  27. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  28. GRB 230727A: AstroSat CZTI detection
  29. GRB 230728A: Swift detection of a burst
  30. Swift GRB230728.12: Global MASTER-Net observations report
  31. GRB 230727A: Swift/BAT-GUANO detection of a burst
  32. Fermi-LAT gamma-ray observations of IceCube-230725A
  33. Fermi-LAT gamma-ray observations of IceCube-230724A
  34. Fermi trigger No 712143685: Global MASTER-Net observations report
  35. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 230727A: Fermi GBM Final Real-time Localization
  37. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
  39. Integral GRB230726.26: Global MASTER-Net observations report
  40. GRB 230723B: Further CAHA observations and host galaxy detection
  41. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  42. Konus-Wind detection of GRB 230723A
  43. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  44. GRB 230723B: ATCA rapid radio follow-up
  45. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  46. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  47. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  48. IBAS trigger number 10337: not a real GRB
  49. Integral GRB230725.99: Global MASTER-Net observations report
  50. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  51. IceCube Alert 230725.90: Global MASTER-Net observations report
  52. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  53. IPN triangulation of GRB 230723A (short)
  54. Fermi Gamma-ray Burst Monitor trigger 711982704/230725540 is not a GRB
  55. GRB 230725B: Fermi GBM Final Real-time Localization
  56. GRB 230725A: Fermi GBM Final Real-time Localization
  57. GRB 230723B: Leavitt Observatory upper limit
  58. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  59. GRB 230723B: Montarrenti Observatory upper limit
  60. GRB 230723B: Optical afterglow candidate from CAHA
  61. GRB 230723B: Bassano Bresciano Observatory upper limit
  62. GRB 230723B: Fermi GBM observation
  63. GRB 230723B: Swift-XRT refined Analysis
  64. GRB 230723B: non-detections from Observatoire de Haute-Provence
  65. IceCube Alert 230724.08: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
  67. Fermi trigger No 711853834: Global MASTER-Net observations report
  68. GRB 230724A: Fermi GBM Final Real-time Localization
  69. Fermi trigger No 711805358: Global MASTER-Net observations report
  70. GRB 230723B: Optical limit from CAHA
  71. GRB 230723B: Swift/UVOT Upper Limits
  72. Swift GRB 230723B: Global MASTER-Net observations report
  73. Swift-XRT position for GRB 230723B
  74. GRB 230723A: AGILE/MCAL detection
  75. GRB 230723B: Swift-XRT observations
  76. LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
  77. GRB 230723B: Swift detection of a burst
  78. Fermi GRB 230723A: Global MASTER-Net observations report
  79. GRB 230723A: Fermi GBM Final Real-time Localization
  80. Swift GRB230720.30: Global MASTER-Net observations report
  81. IPN triangulation of GRB 230715D
  82. Swift Trigger 1180063 is not a GRB
  83. Swift Trigger 1180060 is not a GRB
  84. Swift Trigger 1180055 is not a GRB
  85. GRB 230718A: Final Localization Correction
  86. GRB 230718A: Fermi GBM Final Real-time Localization
  87. Fermi Gamma-ray Burst Monitor trigger 711329677/230717982 is not a GRB
  88. IPN triangulation of GRB 230712C (short)
  89. IPN triangulation of GRB 230712A (short)
  90. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  91. GRB 230717A: Fermi GBM Final Real-time Localization
  92. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  93. Fermi trigger No 711088412: Global MASTER-Net observations report
  94. GRB 230715A: Fermi GBM Final Real-time Localization
  95. Fermi GRB 230713A: Global MASTER-Net observations report
  96. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  97. GRB 230713A: Fermi GBM Final Real-time Localization
  98. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  99. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  100. GRB 230709B: CALET Gamma-Ray Burst Monitor detection

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