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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

12108 results found.

  1. GRB 231111A: Leavitt Observatory optical observations
  2. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  3. GRB 231111A: GECAM-C detection of a long burst (correction)
  4. GRB 231110A: GECAM-B detection (correction)
  5. GRB 231111A: GECAM-C detection of a long burst
  6. GRB 231110A: GECAM detection
  7. GRB 231111A: Swift detection of a burst with an optical counterpart
  8. Swift GRB231111.60: Global MASTER-Net observations report
  9. Swift GRB231110.89: Global MASTER-Net observations report
  10. GRB 231110A: Swift detection of a burst
  11. Fermi GRB 231108A: Global MASTER-Net observations report
  12. Fermi trigger No 721006392: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  14. Fermi GRB 231106A: Global MASTER-Net observations report
  15. Fermi-LAT gamma-ray observations of IceCube-231103A
  16. GRB 231104A: Fermi GBM Observation
  17. Fermi GRB 231103A: Global MASTER-Net observations report
  18. GRB 231104A: AstroSat CZTI detection
  19. GRB 231104A: Fermi-LAT detection
  20. GRB 231104A: Swift/UVOT Upper Limits
  21. Swift GRB231104.07: Global MASTER-Net observations report
  22. Fermi-LAT gamma-ray observations of IceCube-231027A
  23. Fermi trigger No 720498201: Global MASTER-Net observations report
  24. GRB 231030B: GRBAlpha detection
  25. GRB 231030B: Fermi GBM Detection
  26. GRB 231030B: AstroSat CZTI detection
  27. Fermi GRB 231030B: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  30. GRID detection of GRB 231020A
  31. GRB 231028A: AstroSat CZTI detection
  32. Fermi trigger No 720224759: Global MASTER-Net observations report
  33. Swift GRB 231028A: Global MASTER-Net observations report
  34. IceCube Alert 231027.18: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  37. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  38. GRB 231024A: Fermi GBM Observation
  39. GRB 231020A: AstroSat CZTI detection
  40. GRB 231020B: AstroSat CZTI detection
  41. GRB 231024A: Fermi GBM Final Localization
  42. Fermi trigger No 719846439: Global MASTER-Net observations report
  43. The photometry of the transient in Messier 31 field: GMG observation
  44. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  45. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  47. GRB 231020A: Fermi GBM Detection
  48. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  49. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  50. GRB 231020B: Fermi GBM Final Real-time Localization
  51. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  52. Fermi GRB 231020A: Global MASTER-Net observations report
  53. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  54. GRB 231020A: Fermi GBM Final Real-time Localization
  55. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  56. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  57. Konus-Wind detection of GRB 231018A
  58. GRB 231017A: GOTO optical upper limits
  59. GRB 231015A: AstroSat CZTI detection
  60. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  61. Fermi-LAT gamma-ray observations of IceCube-231014A
  62. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  63. GRB 231012A: Fermi GBM Final Real-time Localization
  64. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  66. Fermi-LAT gamma-ray observations of IceCube-231004A
  67. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  68. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  69. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  70. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230927A
  71. Konus-Wind detection of GRB 230919A
  72. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  73. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  74. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  75. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  76. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  77. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  78. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  79. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  80. GRB 230919A: AstroSat CZTI detection
  81. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  82. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  83. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  84. GRB 230917A: AstroSat CZTI detection
  85. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  86. Fermi trigger No 716572242: Global MASTER-Net observations report
  87. Fermi-LAT gamma-ray observations of IceCube-230914A
  88. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  89. Swift GRB230916.11: Global MASTER-Net observations report
  90. Fermi trigger No 716449174: Global MASTER-Net observations report
  91. Fermi trigger No 716419312: Global MASTER-Net observations report
  92. GRB 230913A: Fermi GBM Observation
  93. Swift GRB230913.70: Global MASTER-Net observations report
  94. GRB 230911B: AstroSat CZTI detection
  95. GRB 230911C: Swift-XRT refined Analysis
  96. GRB 230911D: Fermi-LAT detection
  97. GRB230911C: LCOGT Optical Upper Limits
  98. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  99. Konus-Wind detection of GRB 230811D
  100. GRB 230911C: Swift detection of a burst

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