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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"

28058 results found.

  1. GRB 230405B: MeerLICHT upper limits
  2. IceCube Alert 230405.56: Global MASTER-Net observations report
  3. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  4. GRB 230307A: good match with kilonova models
  5. GRB 230307A: short mininum variability timescale compatible with a merger origin
  6. GRB 230405B: Swift/UVOT Upper Limits
  7. GRB 230405B: Enhanced Swift-XRT position
  8. GRB 230405B: Swift detection of a burst
  9. GRB 230404A: AstroSat CZTI detection
  10. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  11. IceCube-230401A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 230328B: Multa observatory optical afterglow observation
  13. GRB 230228A: detection by GTC of the potential host galaxy
  14. GRB 230328B: Swift/UVOT Detection
  15. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  16. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 230328B: 3.6m DOT multiband optical observation
  18. GRB 230328B: Swift-BAT refined analysis
  19. GRB 230328B: Nanshan/NEXT 2nd optical observation
  20. GRB 230328B: OHP/T120 optical observations
  21. GRB 230328B: GIT optical follow-up
  22. GRB 230328B: OASDG optical observations
  23. GRB 230328B: Nanshan/NEXT optical upper limit
  24. GRB 230328B: Swift-XRT refined Analysis
  25. GRB 230328B: Fermi GBM observation
  26. GRB 230328B: Mondy, AbAO and Kitab optical observations
  27. GRB 230328B: Enhanced Swift-XRT position
  28. GRB 230328B: Mondy optical afterglow confirmation
  29. GRB 230328B: Swift detection of a burst with an optical afterglow
  30. GRB 230325A: Swift-BAT refined analysis
  31. GRB 230325A: Swift/UVOT Upper Limits
  32. GRB 230325A: X-shooter optical afterglow and redshift
  33. GRB 230325A: Swift-XRT refined Analysis
  34. GRB 230322B: Swift-BAT refined analysis
  35. GRB 230325A: Enhanced Swift-XRT position
  36. GRB 230325A: Swift detection of a burst
  37. GRB 230320B: Fermi GBM Observation
  38. GRB 230322B: Swift/UVOT Detection
  39. GRB 230322B: Swift-XRT refined Analysis
  40. GRB 230322B: Enhanced Swift-XRT position
  41. GRB 230322B: Swift detection of a burst with optical counterpart
  42. GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
  43. Fermi trigger No 701058254: Global MASTER-Net observations report
  44. GRB 230321B: AstroSat CZTI detection
  45. GRB 230320B: AstroSat CZTI detection
  46. GRB 230321A: BALROG localization (Fermi Trigger 701065308 / GRB 230321182)
  47. GRB 230314A: TURBO Optical Upper Limit
  48. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  49. GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
  50. IPN triangulation of GRB 230309A
  51. GRB 230307A: Far off-axis NuSTAR detection of the GRB
  52. VZLUSAT-2 detection of SGR 1806-20
  53. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  54. GRB 230307A: Swift/UVOT detection
  55. GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
  56. GRB 230307A: Swift-XRT afterglow detection
  57. Swift GRB230311.85: Global MASTER-Net observations report
  58. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  59. Alert from the HAWC Burst Monitor HAWC-230311A
  60. TESS Detection of the Optical Afterglow of GRB230307A
  61. GRB 230307A: GECKO optical observations and detections of the afterglow
  62. GRB 230307A: MAXI/GSC upper limit
  63. Fermi GRB 230310A: Global MASTER-Net observations report
  64. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  65. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  66. GRB 230307A: AstroSat LAXPC detection
  67. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  68. GRB 230308A: AGILE/MCAL detection
  69. GRB 230307A: optical upper limit
  70. Swift Trigger 1159108 is not a GRB
  71. GRB 230307A: Swift/BAT upper limits on the early afterglow
  72. GRB 230307A: Upper limits from a neutrino search with IceCube
  73. GRB 230307A: Swift-XRT observations
  74. Fermi GRB 230307A: Global MASTER-Net observations report
  75. GRB 230228A: VIRT Optical Upper Limit
  76. GRB 230307A: VZLUSAT-2 detection
  77. GRB 230308A: BALROG localization (Fermi Trigger 699975152 / GRB 230308564)
  78. GRB 230307A: BALROG localization (Fermi Trigger 699896651/ GRB 230307656)
  79. GRB 230307A: AstroSat CZTI detection
  80. IPN triangulation of GRB 230307A (long/very bright)
  81. Solar Orbiter STIX observation of GRB 230307A
  82. IceCube-230306A: Upper limits from a search for additional neutrino events in IceCube
  83. Fermi-LAT gamma-ray observations of IceCube-230306A
  84. GRB 230307A: Fermi GBM detection of a very bright GRB
  85. GRB 230307A: GECAM detection of an extremely bright burst
  86. GRB 230228A: Swift-BAT refined analysis
  87. GRB 230228A: Swift/UVOT Upper Limits
  88. GRB 230301B: Fermi GBM Final Real-time Localization
  89. GRB 230228A: Fermi GBM Observation
  90. GRB 230301A: Fermi GBM Final Real-time Localization
  91. GRB 230228A: Swift-XRT refined Analysis
  92. GRB 230228A: Mondy optical upper limit
  93. GRB 230228A: Enhanced Swift-XRT position
  94. GRB 230228A: Nanshan/NEXT optical upper limit
  95. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  96. GRB 230228A: Swift detection of a possibly short burst
  97. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  98. GRB 230216A Mondy Observations
  99. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 230217A: Swift/UVOT Upper Limits

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