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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 S230729z: Identification of a GW compact binary merger candidate
  2. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 230728A: BOOTES-1 optical upper limit
  4. GRB 230728A: Fermi GBM Observation
  5. GRB 230728A: LCOGT Optical Upper Limit
  6. GRB 230728A: Swift/UVOT Upper Limits
  7. GRB 230728A: Swift-XRT refined Analysis
  8. GRB 230728A: Enhanced Swift-XRT position
  9. GRB 230728A: NOT optical observations and possible host galaxy
  10. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  11. GRB 230727A: AstroSat CZTI detection
  12. GRB 230728A: Swift detection of a burst
  13. Swift GRB230728.12: Global MASTER-Net observations report
  14. GRB 230727A: Swift/BAT-GUANO detection of a burst
  15. Fermi-LAT gamma-ray observations of IceCube-230725A
  16. Fermi-LAT gamma-ray observations of IceCube-230724A
  17. Fermi trigger No 712143685: Global MASTER-Net observations report
  18. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 230727A: Fermi GBM Final Real-time Localization
  20. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
  22. Integral GRB230726.26: Global MASTER-Net observations report
  23. GRB 230723B: Further CAHA observations and host galaxy detection
  24. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  25. Konus-Wind detection of GRB 230723A
  26. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  27. GRB 230723B: ATCA rapid radio follow-up
  28. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  29. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  30. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  31. IBAS trigger number 10337: not a real GRB
  32. Integral GRB230725.99: Global MASTER-Net observations report
  33. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube Alert 230725.90: Global MASTER-Net observations report
  35. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  36. IPN triangulation of GRB 230723A (short)
  37. Fermi Gamma-ray Burst Monitor trigger 711982704/230725540 is not a GRB
  38. GRB 230725B: Fermi GBM Final Real-time Localization
  39. GRB 230725A: Fermi GBM Final Real-time Localization
  40. GRB 230723B: Leavitt Observatory upper limit
  41. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  42. GRB 230723B: Montarrenti Observatory upper limit
  43. GRB 230723B: Optical afterglow candidate from CAHA
  44. GRB 230723B: Bassano Bresciano Observatory upper limit
  45. GRB 230723B: Fermi GBM observation
  46. GRB 230723B: Swift-XRT refined Analysis
  47. GRB 230723B: non-detections from Observatoire de Haute-Provence
  48. IceCube Alert 230724.08: Global MASTER-Net observations report
  49. LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
  50. Fermi trigger No 711853834: Global MASTER-Net observations report
  51. GRB 230724A: Fermi GBM Final Real-time Localization
  52. Fermi trigger No 711805358: Global MASTER-Net observations report
  53. GRB 230723B: Optical limit from CAHA
  54. GRB 230723B: Swift/UVOT Upper Limits
  55. Swift GRB 230723B: Global MASTER-Net observations report
  56. Swift-XRT position for GRB 230723B
  57. GRB 230723A: AGILE/MCAL detection
  58. GRB 230723B: Swift-XRT observations
  59. LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
  60. GRB 230723B: Swift detection of a burst
  61. Fermi GRB 230723A: Global MASTER-Net observations report
  62. GRB 230723A: Fermi GBM Final Real-time Localization
  63. Swift GRB230720.30: Global MASTER-Net observations report
  64. IPN triangulation of GRB 230715D
  65. Swift Trigger 1180063 is not a GRB
  66. Swift Trigger 1180060 is not a GRB
  67. Swift Trigger 1180055 is not a GRB
  68. GRB 230718A: Final Localization Correction
  69. GRB 230718A: Fermi GBM Final Real-time Localization
  70. Fermi Gamma-ray Burst Monitor trigger 711329677/230717982 is not a GRB
  71. IPN triangulation of GRB 230712C (short)
  72. IPN triangulation of GRB 230712A (short)
  73. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  74. GRB 230717A: Fermi GBM Final Real-time Localization
  75. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  76. Fermi trigger No 711088412: Global MASTER-Net observations report
  77. GRB 230715A: Fermi GBM Final Real-time Localization
  78. Fermi GRB 230713A: Global MASTER-Net observations report
  79. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  80. GRB 230713A: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  82. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  83. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  84. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  85. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  86. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  87. GRB 230712B: Fermi GBM Final Localization
  88. LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
  89. GRB 230707A: Swift/BAT-GUANO position correction
  90. GRB 230712A: Fermi GBM Final Real-time Localization
  91. IceCube-230708A - Correction to GCN Circular 34170
  92. Fermi trigger No 710741042: Global MASTER-Net observations report
  93. GRB 230709C: GRBAlpha detection
  94. GRB 230709B: GRBAlpha detection
  95. GRB 230709C: Fermi GBM Detection
  96. GRB 230709C: Fermi GBM Final Localization
  97. GRB 230707B: Fermi GBM Observation
  98. GRB 230710A: Fermi GBM Final Real-time Localization
  99. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  100. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate

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