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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. GRB 230828A: GRBAlpha detection
  2. Swift Trigger 1188089 is not a GRB
  3. GRB 230827A: VZLUSAT-2 detection
  4. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  5. GRB 230826A: VZLUSAT-2 detection
  6. GRB 230827B: VZLUSAT-2 detection
  7. GRB 230827B / GRB 230827256: Fermi GBM Observation
  8. GRB 230827A: GRBAlpha detection
  9. Subject: GRB230826A: Swift/UVOT upper limits
  10. GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
  11. Fermi trigger No 714809315: Global MASTER-Net observations report
  12. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  13. Fermi GRB 230827A: Global MASTER-Net observations report
  14. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  15. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  16. GRB 230827A: Fermi GBM Final Real-time Localization
  17. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  18. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  19. GRB 230826A: GRBAlpha detection
  20. GRB 230826A: Fermi GBM Observation
  21. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  22. GRB 230826A: Enhanced Swift-XRT position
  23. GRB 230826A: Swift-XRT refined Analysis
  24. GRB 230826A: Mondy optical observations
  25. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  26. GRB 230826A: Swift detection of a burst
  27. GRB 230826A: Fermi GBM Final Real-time Localization
  28. Swift GRB230826.81: Global MASTER-Net observations report
  29. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  30. GRB 230824A: AKO Photometric Follow-up Observations
  31. GRB 230818B: CALET Gamma-Ray Burst Monitor detection
  32. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  33. Swift GRB230825.85: Global MASTER-Net observations report
  34. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  35. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  36. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  37. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  38. Swift GRB230825.75: Global MASTER-Net observations report
  39. GRB 230812B: radio detection with the VLA
  40. Swift Trigger 1187199 is not an astrophysical event
  41. Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB
  42. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  43. LIGO/Virgo/KAGRA S230825k: Updated Sky localization
  44. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  45. LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
  46. Fermi trigger No 714618399: Global MASTER-Net observations report
  47. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  48. GRB 230824A: AKO Optical Afterglow Candidate
  49. Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  50. IBAS trigger 10375 is not a GRB
  51. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  52. Integral GRB230824.72: Global MASTER-Net observations report
  53. GRB 230824B: AstroSat CZTI detection
  54. GRB 230824A: Swift detection of a burst
  55. Swift GRB230824.58: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S230824r: Updated Sky localization
  57. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  58. Swift GRB230824.10: Global MASTER-Net observations report
  59. Swift Trigger 1186908 is not a GRB
  60. GRB 230822A: Fermi GBM Observation
  61. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  62. GRB 230822A: Swift/BAT-GUANO detection of a burst
  63. IceCube-230823A: Event likely due to background
  64. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  65. GRB 230812B: AstroSat LAXPC detection
  66. GRB 230818B: VZLUSAT-2 detection
  67. GRB 230818B: AstroSat CZTI detection
  68. GRID detection of GRB 230818A
  69. LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
  70. GRB 230822A: Fermi GBM Final Real-time Localization
  71. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  72. GRB 230812B: Assy optical observations, possible SN rise
  73. GRB 230815A: ATCA detection of radio counterpart
  74. Swift GRB230821.64: Global MASTER-Net observations report
  75. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  76. GRB 230818A: Swift-BAT refined analysis
  77. GRB 20230818A: GIT optical upper limit
  78. Swift Trigger 1186391 is not a GRB
  79. Swift Trigger 1186390 is not a GRB
  80. Konus-Wind detection of GRB 230818A
  81. Swift Trigger 1186386 is not a GRB
  82. Swift triggers 1186294-1186304 are not astrophysical transients
  83. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  84. Swift GRB230820.81: Global MASTER-Net observations report
  85. Swift GRB230820.80: Global MASTER-Net observations report
  86. GRB 230820A: AstroSat CZTI detection
  87. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  88. Swift GRB230820.82: Global MASTER-Net observations report
  89. Swift Triggers 1186280 and 1186291 are not GRBs
  90. GRB 230818A: Fermi GBM Observation
  91. GRB 230812B: GIT Confirmation of SN rise
  92. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  93. GRB 230818A: Nickel and KAIT telescope optical observations
  94. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  95. GRB 230812B: SAO RAS Zeiss-1000 observations
  96. GRB 230818A: further SAO RAS Zeiss-1000 observations
  97. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  98. GRB 230818A: AKO Upper Limit
  99. GRB 230818A: AstroSat CZTI detection
  100. GRB 230818A: Tautenburg observations

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