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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"

28097 results found.

  1. GRB 230414B Swift-BAT refined analysis
  2. GRB 230415A: Fermi GBM detection
  3. GRB 230414B: Swift/UVOT Detection
  4. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  5. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  6. GRB 230415A: Swift/BAT-GUANO detection
  7. VIRT optical transient detection
  8. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  9. GRB 230307A: iTelescope optical upper limit (likely)
  10. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  11. GRB 230414B: Lulin 40cm-SLT optical limit
  12. GRB 230414B: Bassano Bresciano Observatory optical observations
  13. GRB 230414B: AbAO optical observations
  14. GRB 230414B: Swift-XRT refined Analysis
  15. GRB 230414B: Dabancheng/GHOST optical observations
  16. GRB 230414B: SAO RAS optical observations
  17. GRB 230414B: Enhanced Swift-XRT position
  18. GRB 230414B: 1.3m DFOT Optical observations
  19. GRB 230414B: GROWTH India Telescope afterglow confirmation
  20. GRB 230414B: Nanshan/HMT optical afterglow detection
  21. GRB 230414A: Mondy optical afterglow candidate
  22. GRB 230414B: Swift detection of a burst
  23. GRB 230328B: redshift lower limit estimating
  24. GRB 230409B: Mondy optical upper limit
  25. GRB 230409B: OHP/T193 optical upper limit
  26. GRB 230410B: VZLUSAT-2 detection
  27. GRB 230409D: VZLUSAT-2 detection
  28. GRB 230410B: AGILE detection of a burst
  29. GRB 230409B: Swift-XRT refined Analysis
  30. GRB 230409B: Swift-BAT refined analysis
  31. GRB 230409B: Swift/UVOT Detection
  32. GRB 230409B: Enhanced Swift-XRT position
  33. MAXI GRB230408.82: Global MASTER-Net observations report
  34. GRB 230409B: Swift detection of a burst
  35. GRB 230405B: VZLUSAT-2 detection
  36. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  37. Fermi-LAT gamma-ray observations of IceCube-230405A
  38. GRB 230405B: Swift-XRT refined Analysis
  39. GRB 230405B: Fermi GBM Observation
  40. GRB 230405B: MeerLICHT upper limits
  41. IceCube Alert 230405.56: Global MASTER-Net observations report
  42. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  43. GRB 230307A: good match with kilonova models
  44. GRB 230307A: short mininum variability timescale compatible with a merger origin
  45. GRB 230405B: Swift/UVOT Upper Limits
  46. GRB 230405B: Enhanced Swift-XRT position
  47. GRB 230405B: Swift detection of a burst
  48. GRB 230404A: AstroSat CZTI detection
  49. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  50. IceCube-230401A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 230328B: Multa observatory optical afterglow observation
  52. GRB 230228A: detection by GTC of the potential host galaxy
  53. GRB 230328B: Swift/UVOT Detection
  54. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  55. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  56. GRB 230328B: 3.6m DOT multiband optical observation
  57. GRB 230328B: Swift-BAT refined analysis
  58. GRB 230328B: Nanshan/NEXT 2nd optical observation
  59. GRB 230328B: OHP/T120 optical observations
  60. GRB 230328B: GIT optical follow-up
  61. GRB 230328B: OASDG optical observations
  62. GRB 230328B: Nanshan/NEXT optical upper limit
  63. GRB 230328B: Swift-XRT refined Analysis
  64. GRB 230328B: Fermi GBM observation
  65. GRB 230328B: Mondy, AbAO and Kitab optical observations
  66. GRB 230328B: Enhanced Swift-XRT position
  67. GRB 230328B: Mondy optical afterglow confirmation
  68. GRB 230328B: Swift detection of a burst with an optical afterglow
  69. GRB 230325A: Swift-BAT refined analysis
  70. GRB 230325A: Swift/UVOT Upper Limits
  71. GRB 230325A: X-shooter optical afterglow and redshift
  72. GRB 230325A: Swift-XRT refined Analysis
  73. GRB 230322B: Swift-BAT refined analysis
  74. GRB 230325A: Enhanced Swift-XRT position
  75. GRB 230325A: Swift detection of a burst
  76. GRB 230320B: Fermi GBM Observation
  77. GRB 230322B: Swift/UVOT Detection
  78. GRB 230322B: Swift-XRT refined Analysis
  79. GRB 230322B: Enhanced Swift-XRT position
  80. GRB 230322B: Swift detection of a burst with optical counterpart
  81. GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
  82. Fermi trigger No 701058254: Global MASTER-Net observations report
  83. GRB 230321B: AstroSat CZTI detection
  84. GRB 230320B: AstroSat CZTI detection
  85. GRB 230321A: BALROG localization (Fermi Trigger 701065308 / GRB 230321182)
  86. GRB 230314A: TURBO Optical Upper Limit
  87. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  88. GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
  89. IPN triangulation of GRB 230309A
  90. GRB 230307A: Far off-axis NuSTAR detection of the GRB
  91. VZLUSAT-2 detection of SGR 1806-20
  92. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  93. GRB 230307A: Swift/UVOT detection
  94. GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
  95. GRB 230307A: Swift-XRT afterglow detection
  96. Swift GRB230311.85: Global MASTER-Net observations report
  97. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  98. Alert from the HAWC Burst Monitor HAWC-230311A
  99. TESS Detection of the Optical Afterglow of GRB230307A
  100. GRB 230307A: GECKO optical observations and detections of the afterglow

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