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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').
  1. GRB231230A: Fermi GBM Observation
  2. GRB 231230A: Swift-XRT refined Analysis
  3. GRB 231230A: GOTO optical upper limits
  4. GRB 231230A: Enhanced Swift-XRT position
  5. GRB 231230A: Swift/UVOT Upper Limits
  6. GRB 231230A: NOT optical upper limits
  7. Fermi trigger No 725592555: Global MASTER-Net observations report
  8. GRB 231230A: Prompt enhanced Swift-XRT position
  9. GRB 231230A: Swift detection of a burst
  10. Swift GRB231230.06: Global MASTER-Net observations report
  11. GRB 231230A: Fermi GBM Final Real-time Localization
  12. GRB 231210B: BOOTES-7 optical upper limit
  13. Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
  14. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  15. IPN triangulation of GRB 231224A (short)
  16. LIGO/Virgo/KAGRA S231226av: Updated Sky localization
  17. LIGO/Virgo/KAGRA S231226av: Identification of a GW compact binary merger candidate
  18. Fermi trigger No 725143760: Global MASTER-Net observations report
  19. GRB 231224A: Fermi GBM Final Real-time Localization
  20. GRB 231222B: GRBAlpha detection
  21. LIGO/Virgo/KAGRA S231224e: Updated Sky localization and Source Classification
  22. LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S231223j: Updated Sky localization
  24. GRB 231222B: Swift-XRT afterglow detection
  25. LIGO/Virgo/KAGRA S231223j: Identification of a GW compact binary merger candidate
  26. Fermi trigger No 724921799: Global MASTER-Net observations report
  27. GRB 231222B: Fermi GBM Detection
  28. LAT GRB231222.31: Global MASTER-Net observations report
  29. GRB 231222B: Fermi-LAT detection
  30. GRB 231222A: Tiled Swift observations
  31. IceCube-231211A: GRANDMA observations of PKS2047+098
  32. GRID detection of GRB 231215A
  33. GRB 231222A: Fermi GBM Final Real-time Localization
  34. GRB 231220A: Swift-XRT follow-up observations
  35. GRB 231220A: Swift ToO observations
  36. GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
  37. Fermi trigger No 724781422: Global MASTER-Net observations report
  38. GRB 231220A: Fermi GBM Final Real-time Localization
  39. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  40. Fermi trigger No 724698747: Global MASTER-Net observations report
  41. GRB 231219A: Fermi GBM Final Real-time Localization
  42. GRID detection of GRB 231205B
  43. GRID detection of GRB 231205A
  44. GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
  45. GRB 231214B: Fermi GBM observation
  46. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  47. GRB 231216A: 10.4 m GTC optical upper limit
  48. GRB 231215A: AMI-LA radio detection
  49. GRB 231216A: Nanshan/HMT optical upper limit
  50. GRB 231216A: LCOGT Optical Upper Limits
  51. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  52. GRB 231216A: Swift-XRT refined analysis correction
  53. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  54. GRB 231216A: Swift-XRT refined Analysis
  55. GRB 231216A: AST3-3 YaoAn Optical Upper Limit
  56. GRB 231216A: REM NIR upper limits
  57. GRB 231216A: Swift/UVOT Upper Limits
  58. GRB 231216A: Swift-BAT refined analysis
  59. GRB 231215A: Swift-BAT refined analysis
  60. GRB 231214A: Swift-BAT refined analysis
  61. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  62. GRB 231216A: GIT optical upper limit
  63. GRB 231216A: NOT optical upper limits
  64. GRB 231216A: BOOTES-2/TELMA optical upper limit
  65. GRB 231215A: GRBAlpha detection
  66. Swift GRB231216.77: Global MASTER-Net observations report
  67. GRB 231216A: Swift detection of a burst
  68. Konus-Wind detection of GRB 231215A
  69. GRB 231215A: optical afterglow detection from the INAF Asiago Observatory
  70. GRB 231215A: NOT optical observations
  71. GRB 231214A: Swift/UVOT Upper Limits
  72. GRB 231215A: Redshift from OSIRIS+ / GTC
  73. GRB 231205B: VZLUSAT-2 detection
  74. GRB 231204A: VZLUSAT-2 detection
  75. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  76. GRB 231215A: Fermi GBM observation
  77. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  78. GRB 231215A : OHP/T193 optical afterglow detection
  79. GRB 231215A: Swift/UVOT Detection
  80. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  81. GRB 231215A: Swift-XRT refined Analysis
  82. GRB 231215A: BOOTES-4/MET optical detection
  83. GRB 231215A: AKO Optical Upper Limit
  84. GRB 231215A: AGILE detection
  85. GRB 231214A: Fermi GBM observation
  86. Konus-Wind detection of GRB 231210B
  87. ATCA observations of GRB 231210B
  88. GRB 231215A: Enhanced Swift-XRT position
  89. Fermi trigger No 724326442: Global MASTER-Net observations report
  90. GRB 231214A: REM optical/NIR upper limits
  91. GRB 231215A: GROWTH-India optical follow-up
  92. GRB 231215A : Nanshan/HMT optical observations
  93. GRB 231215A: AstroSat CZTI detection
  94. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  95. GRB 231214A: Swift-XRT refined Analysis
  96. GRB 231215A: Mondy optical bright afterglow detection
  97. GRB 231214A: AstroSat CZTI detection
  98. GRB 231215C: MASTER OT detection
  99. Swift GRB231215.41: Global MASTER-Net observations report
  100. GRB 231215A: Swift-XRT observations

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