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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"

27777 results found.

  1. GRB 230911A: Fermi GBM Final Real-time Localization
  2. GRB 230906A: BlackGEM upper limits
  3. GRB 230903A: TESS observations of optical emission
  4. GRB 230906A: AstroSat CZTI detection
  5. GRB 230910A: Fermi GBM Final Real-time Localization
  6. GRB 230908A: GRBAlpha detection
  7. GRB 230908A: AstroSat CZTI detection
  8. Glowbug gamma-ray detection GRB 230905B
  9. GRB 230906A: Swift/UVOT Upper Limits
  10. GRID detection of GRB 230827A
  11. GRB 230906A: Swift-XRT observations
  12. Konus-Wind detection of GRB 230906A (short)
  13. IPN triangulation of GRB 230906A (short)
  14. GRB 230906A: Swift ToO observations
  15. GRB 230905B: AstroSat CZTI detection
  16. Swift Attitude Control Affecting Some UVOT Images
  17. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  18. GRB 230906A: Fermi GBM Final Localizationn
  19. GRB 230905B: GECAM-C detection of a long burst
  20. GRB 230905A: Fermi GBM Final Real-time Localization
  21. GRB 230903A: Swift-XRT refined Analysis
  22. GRB 230903A: Enhanced Swift-XRT position
  23. GRB 230903A: VLT/X-shooter optical observations
  24. GRB 230903A: Swift-BAT refined analysis
  25. GRB 230904C: Fermi GBM Final Localization
  26. GRB 230903A: Fermi GBM detection
  27. GRB 230904A: Fermi GBM Final Real-time Localization
  28. GRB 230903A: LCOGT Optical Upper Limits
  29. GRB 230903A: Swift detection of a burst
  30. Swift GRB230903.72: Global MASTER-Net observations report
  31. GRB 230903A: Fermi GBM Final Real-time Localization
  32. GRB 230827B: Glowbug gamma-ray detection
  33. GRB 230827A: Glowbug gamma-ray detection
  34. GRB 230826A: Glowbug gamma-ray detection
  35. GRB 230827B: Swift-XRT afterglow detection
  36. LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
  37. GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
  38. GRB 230827B: Swift ToO observations
  39. GRB 230827A: Fermi GBM Observation
  40. GRB 230827B: CALET Gamma-Ray Burst Monitor detection
  41. GRB 230826A: Swift-BAT refined analysis
  42. GRB 230828A: AstroSat CZTI detection
  43. GRB 230828A: GRBAlpha detection
  44. Swift Trigger 1188089 is not a GRB
  45. GRB 230827A: VZLUSAT-2 detection
  46. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  47. GRB 230826A: VZLUSAT-2 detection
  48. GRB 230827B: VZLUSAT-2 detection
  49. GRB 230827A: GRBAlpha detection
  50. Subject: GRB230826A: Swift/UVOT upper limits
  51. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  52. GRB 230827A: Fermi GBM Final Real-time Localization
  53. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  54. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  55. GRB 230826A: GRBAlpha detection
  56. GRB 230826A: Fermi GBM Observation
  57. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  58. GRB 230826A: Enhanced Swift-XRT position
  59. GRB 230826A: Swift-XRT refined Analysis
  60. GRB 230826A: Mondy optical observations
  61. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  62. GRB 230826A: Swift detection of a burst
  63. GRB 230826A: Fermi GBM Final Real-time Localization
  64. Swift GRB230826.81: Global MASTER-Net observations report
  65. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  66. GRB 230824A: AKO Photometric Follow-up Observations
  67. GRB 230818B: CALET Gamma-Ray Burst Monitor detection
  68. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  69. Swift GRB230825.85: Global MASTER-Net observations report
  70. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  71. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  72. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  73. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  74. Swift GRB230825.75: Global MASTER-Net observations report
  75. GRB 230812B: radio detection with the VLA
  76. Swift Trigger 1187199 is not an astrophysical event
  77. Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB
  78. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  79. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  80. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  81. GRB 230824A: AKO Optical Afterglow Candidate
  82. Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  83. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  84. GRB 230824B: AstroSat CZTI detection
  85. GRB 230824A: Swift detection of a burst
  86. Swift GRB230824.58: Global MASTER-Net observations report
  87. Swift GRB230824.10: Global MASTER-Net observations report
  88. Swift Trigger 1186908 is not a GRB
  89. GRB 230822A: Fermi GBM Observation
  90. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  91. GRB 230822A: Swift/BAT-GUANO detection of a burst
  92. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  93. GRB 230812B: AstroSat LAXPC detection
  94. GRB 230818B: VZLUSAT-2 detection
  95. GRB 230818B: AstroSat CZTI detection
  96. GRID detection of GRB 230818A
  97. GRB 230822A: Fermi GBM Final Real-time Localization
  98. GRB 230815A: ATCA detection of radio counterpart
  99. Swift GRB230821.64: Global MASTER-Net observations report
  100. GRB 230818A: Swift-BAT refined analysis

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