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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"

11779 results found.

  1. GRB 231104A: AstroSat CZTI detection
  2. GRB 231104A: Fermi-LAT detection
  3. GRB 231104A: Swift/UVOT Upper Limits
  4. Swift GRB231104.07: Global MASTER-Net observations report
  5. Fermi-LAT gamma-ray observations of IceCube-231027A
  6. Fermi trigger No 720498201: Global MASTER-Net observations report
  7. GRB 231030B: GRBAlpha detection
  8. GRB 231030B: Fermi GBM Detection
  9. GRB 231030B: AstroSat CZTI detection
  10. Fermi GRB 231030B: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  12. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  13. GRID detection of GRB 231020A
  14. GRB 231028A: AstroSat CZTI detection
  15. Fermi trigger No 720224759: Global MASTER-Net observations report
  16. Swift GRB 231028A: Global MASTER-Net observations report
  17. IceCube Alert 231027.18: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  19. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  20. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  21. GRB 231024A: Fermi GBM Observation
  22. GRB 231020A: AstroSat CZTI detection
  23. GRB 231020B: AstroSat CZTI detection
  24. GRB 231024A: Fermi GBM Final Localization
  25. Fermi trigger No 719846439: Global MASTER-Net observations report
  26. The photometry of the transient in Messier 31 field: GMG observation
  27. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  28. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  30. GRB 231020A: Fermi GBM Detection
  31. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  32. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  33. GRB 231020B: Fermi GBM Final Real-time Localization
  34. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  35. Fermi GRB 231020A: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  37. GRB 231020A: Fermi GBM Final Real-time Localization
  38. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  39. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  40. Konus-Wind detection of GRB 231018A
  41. GRB 231017A: GOTO optical upper limits
  42. GRB 231015A: AstroSat CZTI detection
  43. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  44. Fermi-LAT gamma-ray observations of IceCube-231014A
  45. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  46. GRB 231012A: Fermi GBM Final Real-time Localization
  47. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  49. Fermi-LAT gamma-ray observations of IceCube-231004A
  50. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  53. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230927A
  54. Konus-Wind detection of GRB 230919A
  55. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  59. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  60. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  61. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  62. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  63. GRB 230919A: AstroSat CZTI detection
  64. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  65. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  66. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  67. GRB 230917A: AstroSat CZTI detection
  68. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  69. Fermi trigger No 716572242: Global MASTER-Net observations report
  70. Fermi-LAT gamma-ray observations of IceCube-230914A
  71. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  72. Swift GRB230916.11: Global MASTER-Net observations report
  73. Fermi trigger No 716449174: Global MASTER-Net observations report
  74. Fermi trigger No 716419312: Global MASTER-Net observations report
  75. GRB 230913A: Fermi GBM Observation
  76. Swift GRB230913.70: Global MASTER-Net observations report
  77. GRB 230911B: AstroSat CZTI detection
  78. GRB 230911C: Swift-XRT refined Analysis
  79. GRB 230911D: Fermi-LAT detection
  80. GRB230911C: LCOGT Optical Upper Limits
  81. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  82. Konus-Wind detection of GRB 230811D
  83. GRB 230911C: Swift detection of a burst
  84. GRB 230906A: AstroSat CZTI detection
  85. GRB 230908A: GRBAlpha detection
  86. GRB 230908A: AstroSat CZTI detection
  87. Konus-Wind detection of GRB 230906A (short)
  88. IPN triangulation of GRB 230906A (short)
  89. GRB 230905B: AstroSat CZTI detection
  90. Fermi GRB 230906A: Global MASTER-Net observations report
  91. GRB 230905B: GECAM-C detection of a long burst
  92. GRB 230903A: Swift-XRT refined Analysis
  93. GRB 230904C: Fermi GBM Final Localization
  94. Fermi trigger No 715552087: Global MASTER-Net observations report
  95. Fermi trigger No 715429986: Global MASTER-Net observations report
  96. GRB 230903A: LCOGT Optical Upper Limits
  97. GRB 230903A: Swift detection of a burst
  98. Swift GRB230903.72: Global MASTER-Net observations report
  99. GRB 230828A: AstroSat CZTI detection
  100. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV

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