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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"

27784 results found.

  1. GRB 231230A: Fermi GBM Final Real-time Localization
  2. GRB 231210B: BOOTES-7 optical upper limit
  3. Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
  4. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  5. IPN triangulation of GRB 231224A (short)
  6. GRB 231224A: Fermi GBM Final Real-time Localization
  7. GRB 231222B: GRBAlpha detection
  8. GRB 231222B: Swift-XRT afterglow detection
  9. GRB 231222B: Fermi GBM Detection
  10. GRB 231222B: Fermi-LAT detection
  11. GRB 231222A: Tiled Swift observations
  12. IceCube-231211A: GRANDMA observations of PKS2047+098
  13. GRID detection of GRB 231215A
  14. GRB 231222A: Fermi GBM Final Real-time Localization
  15. GRB 231220A: Swift-XRT follow-up observations
  16. GRB 231220A: Swift ToO observations
  17. GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
  18. GRB 231220A: Fermi GBM Final Real-time Localization
  19. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  20. GRB 231219A: Fermi GBM Final Real-time Localization
  21. GRID detection of GRB 231205B
  22. GRID detection of GRB 231205A
  23. GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
  24. GRB 231214B: Fermi GBM observation
  25. GRB 231216A: 10.4 m GTC optical upper limit
  26. GRB 231215A: AMI-LA radio detection
  27. GRB 231216A: Nanshan/HMT optical upper limit
  28. GRB 231216A: LCOGT Optical Upper Limits
  29. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  30. GRB 231216A: Swift-XRT refined analysis correction
  31. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  32. GRB 231216A: Swift-XRT refined Analysis
  33. GRB 231216A: AST3-3 YaoAn Optical Upper Limit
  34. GRB 231216A: REM NIR upper limits
  35. GRB 231216A: Swift/UVOT Upper Limits
  36. GRB 231216A: Swift-BAT refined analysis
  37. GRB 231215A: Swift-BAT refined analysis
  38. GRB 231214A: Swift-BAT refined analysis
  39. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  40. GRB 231216A: GIT optical upper limit
  41. GRB 231216A: BOOTES-2/TELMA optical upper limit
  42. GRB 231215A: GRBAlpha detection
  43. Swift GRB231216.77: Global MASTER-Net observations report
  44. GRB 231216A: Swift detection of a burst
  45. Konus-Wind detection of GRB 231215A
  46. GRB 231215A: optical afterglow detection from the INAF Asiago Observatory
  47. GRB 231215A: NOT optical observations
  48. GRB 231214A: Swift/UVOT Upper Limits
  49. GRB 231205B: VZLUSAT-2 detection
  50. GRB 231204A: VZLUSAT-2 detection
  51. GRB 231215A: Fermi GBM observation
  52. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  53. GRB 231215A : OHP/T193 optical afterglow detection
  54. GRB 231215A: Swift/UVOT Detection
  55. GRB 231215A: Swift-XRT refined Analysis
  56. GRB 231215A: BOOTES-4/MET optical detection
  57. GRB 231215A: AKO Optical Upper Limit
  58. GRB 231215A: AGILE detection
  59. GRB 231214A: Fermi GBM observation
  60. Konus-Wind detection of GRB 231210B
  61. GRB 231215A: Enhanced Swift-XRT position
  62. GRB 231214A: REM optical/NIR upper limits
  63. GRB 231215A: GROWTH-India optical follow-up
  64. GRB 231215A : Nanshan/HMT optical observations
  65. GRB 231215A: AstroSat CZTI detection
  66. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  67. GRB 231214A: Swift-XRT refined Analysis
  68. GRB 231215A: Mondy optical bright afterglow detection
  69. GRB 231214A: AstroSat CZTI detection
  70. GRB 231215C: MASTER OT detection
  71. Swift GRB231215.41: Global MASTER-Net observations report
  72. GRB 231215A: Swift-XRT observations
  73. GRB 231215B: Fermi GBM Final Real-time Localization
  74. GRB 231215A: Swift detection of a burst
  75. GRB 231214A: Fermi-LAT detection
  76. GRB 231214A: Enhanced Swift-XRT position
  77. GRB 231214B: Swift/BAT-GUANO detection of a burst
  78. GRB231214A: BOOTES-6/DPRT optical upper limit
  79. Swift GRB231214.85: Global MASTER-Net observations report
  80. GRB 231214A: Swift detection of a burst
  81. GRB 231214A: Fermi GBM Final Real-time Localization
  82. GRB 231210B: REM optical/NIR upper limits
  83. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  84. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  85. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  86. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  87. GRB 231212A: GECAM-C detection of a likely short burst
  88. GRB 231210B: MeerLICHT afterglow observations
  89. GRB 231210B: Swift-BAT refined analysis
  90. GRB 231210B: Swift-XRT refined Analysis
  91. GRB 231210B: Enhanced Swift-XRT position
  92. GRB 231210B: VLT/X-shooter redshift
  93. GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
  94. GRB 231210B: Swift detection of a burst with optical counterpart
  95. Swift GRB231210.90: Global MASTER-Net OT detection
  96. Swift GRB231210.90: Global MASTER-Net observations report
  97. IPN triangulation of GRB 231129C
  98. GRB 231210A: Fermi GBM Final Real-time Localization
  99. GRB 231208A: GRBAlpha detection
  100. GRB231205B: Swift/UVOT Upper Limits

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