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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"

11757 results found.

  1. GRB 240114A: MAXI/GSC detection
  2. Fermi GRB 240112D: Global MASTER-Net observations report
  3. Fermi trigger No 726774492: Global MASTER-Net observations report
  4. Swift GRB 240112C: Global MASTER-Net observations report
  5. GRB 240112A: GECAM detection of a burst
  6. GRB 240110A: AstroSat CZTI detection
  7. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  8. Konus-Wind detection of GRB 240101C
  9. GRB 231215A: radio detection with the VLA
  10. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  11. GRB 240107A: MAXI/GSC detection
  12. GRB 240106B: Fermi GBM Final Real-time Localization
  13. Fermi trigger No 726194053: Global MASTER-Net observations report
  14. IceCube Alert 240105.52: Global MASTER-Net observations report
  15. GRB 240102A: 1.3m DFOT optical upper limit
  16. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  17. GRB 240102C: AstroSat CZTI detection
  18. GRB 240101C: AstroSat CZTI detection
  19. GRB 231230A: Swift-BAT refined analysis
  20. GRB 240101A: Swift-BAT refined analysis
  21. GRB 240102A: Swift-XRT refined Analysis
  22. GRB 240101A: Swift-XRT refined Analysis
  23. GRB 240101B: Swift detection of a burst
  24. GRB 240101A: Swift detection of a burst
  25. Fermi trigger No 725806648: Global MASTER-Net observations report
  26. GRB 231230A: Swift-XRT refined Analysis
  27. Fermi trigger No 725592555: Global MASTER-Net observations report
  28. GRB 231230A: Prompt enhanced Swift-XRT position
  29. GRB 231230A: Swift detection of a burst
  30. Swift GRB231230.06: Global MASTER-Net observations report
  31. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  32. IPN triangulation of GRB 231224A (short)
  33. Fermi trigger No 725143760: Global MASTER-Net observations report
  34. GRB 231224A: Fermi GBM Final Real-time Localization
  35. LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
  36. GRB 231222B: Swift-XRT afterglow detection
  37. Fermi trigger No 724921799: Global MASTER-Net observations report
  38. GRB 231222B: Fermi-LAT detection
  39. IceCube-231211A: GRANDMA observations of PKS2047+098
  40. Fermi trigger No 724781422: Global MASTER-Net observations report
  41. GRB 231220A: Fermi GBM Final Real-time Localization
  42. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  43. Fermi trigger No 724698747: Global MASTER-Net observations report
  44. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  45. GRB 231216A: 10.4 m GTC optical upper limit
  46. GRB 231216A: Nanshan/HMT optical upper limit
  47. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  48. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  49. GRB 231216A: Swift-XRT refined Analysis
  50. GRB 231215A: Swift-BAT refined analysis
  51. GRB 231216A: Swift detection of a burst
  52. Konus-Wind detection of GRB 231215A
  53. GRB 231215A: NOT optical observations
  54. GRB 231204A: VZLUSAT-2 detection
  55. GRB 231215A: AKO Optical Upper Limit
  56. GRB 231214A: Fermi GBM observation
  57. Konus-Wind detection of GRB 231210B
  58. GRB 231215A: AstroSat CZTI detection
  59. GRB 231214A: Swift-XRT refined Analysis
  60. GRB 231214A: AstroSat CZTI detection
  61. Swift GRB231215.41: Global MASTER-Net observations report
  62. GRB 231214A: Fermi-LAT detection
  63. GRB 231214B: Swift/BAT-GUANO detection of a burst
  64. GRB231214A: BOOTES-6/DPRT optical upper limit
  65. Fermi trigger No 724278269: Global MASTER-Net observations report
  66. Fermi trigger No 724233240: Global MASTER-Net observations report
  67. Swift GRB231214.85: Global MASTER-Net observations report
  68. GRB 231214A: Swift detection of a burst
  69. GRB 231214A: Fermi GBM Final Real-time Localization
  70. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  71. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  72. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  73. GRB 231212A: GECAM-C detection of a likely short burst
  74. Fermi trigger No 724035412: Global MASTER-Net observations report
  75. GRB 231210B: MeerLICHT afterglow observations
  76. GRB 231210B: Swift-BAT refined analysis
  77. GRB 231210B: Swift-XRT refined Analysis
  78. Fermi trigger No 723906955: Global MASTER-Net observations report
  79. GRB 231208A: AstroSat CZTI detection of a faint burst
  80. Fermi trigger No 723581802: Global MASTER-Net observations report
  81. GRB 231205B: Ondrejov D50 optical upper limit
  82. Fermi-LAT gamma-ray observations of IceCube-231202A
  83. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  84. GRB 231206A: GECAM-B detection of a short burst (correction)
  85. GRB 231206A: GECAM-B detection of a short burst
  86. GRB 231205B: Nanshan/HMT optical upper limit
  87. GRB 231205B: GECAM-B detection of a long burst
  88. GRB 231204A: Glowbug gamma-ray detection
  89. GRB 231204A: CALET Gamma-Ray Burst Monitor detection
  90. Fermi-LAT daily aperture light curve of T CrB now available
  91. GRB 231204A: AstroSat CZTI detection
  92. GRB 231205A: GECAM-B detection of a short burst
  93. Fermi trigger No 723435916: Global MASTER-Net observations report
  94. Fermi trigger No 723326169: Global MASTER-Net observations report
  95. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  96. Fermi trigger No 723412808: Global MASTER-Net observations report
  97. GRB 231204A: Fermi GBM Final Real-time Localization
  98. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  99. Konus-Wind detection of GRB 231129C
  100. Fermi trigger No 723149952: Global MASTER-Net observations report

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