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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"

21458 results found.

  1. GRB 230628E: LCOGT Optical Upper Limit
  2. Swift GRB230628.93: Global MASTER-Net observations report
  3. GRB 230628E: Swift detection of a burst
  4. GRB 230628B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  5. GRB 230623B: CALET Gamma-Ray Burst Monitor detection
  6. Konus-Wind detection of GRB 230616A
  7. GRB 230618A: Swift-BAT refined analysis
  8. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  9. GRB 230622A: Swift-BAT refined analysis
  10. GRB 230623A: Swift-XRT observations
  11. GRB 230623B: Swift/BAT-GUANO detection of a long burst outside the coded FOV 
  12. GRB 230623A: Tiled Swift observations
  13. GRB 230623A: Tiled Swift observations
  14. GRB 230622A: ATCA rapid radio follow-up
  15. GRB 230622A: Swift-XRT refined Analysis
  16. Swift GRB 230622A: Global MASTER-Net observations report
  17. GRB 230622A: Swift detection of a burst
  18. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  19. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  20. IPN triangulation of GRB 230616A (short)
  21. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  22. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  23. GRB 230618A: Enhanced Swift-XRT position
  24. GRB 230618A: Swift/UVOT Upper Limits
  25. GRB 230618A: Swift-XRT refined Analysis
  26. GRB 230616A: Swift-XRT observations
  27. GRB 230618A: KAIT Optical Observations
  28. Swift GRB 230618A: Global MASTER-Net observations report
  29. GRB230618A: LCOGT Optical Observations
  30. GRB 230618A: Prompt enhanced Swift-XRT position
  31. GRB 230618A: Swift detection of a burst
  32. GRB 230616A: Swift ToO observations
  33. GRB 230616A: AstroSat CZTI detection
  34. GRB 230616A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  35. GRB 230614B: Fermi GBM Observation
  36. GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
  37. GRB 230606A: LCOGT Optical Observations
  38. GRB 230506B: Chandra localization of the X-ray afterglow
  39. GRB 230606A: Swift-BAT refined analysis
  40. GRB 230606A: Gaoyazi/GOT optical upper limit
  41. GRB 230606A: Fermi GBM Observation
  42. GRB 230606A: BOOTES-5/JGT optical upper limit
  43. GRB 230606A: Swift-XRT refined Analysis
  44. GRB 230606A: Swift/UVOT Upper Limits
  45. GRB 230606A: Enhanced Swift-XRT position
  46. GRB 230606A: Swift detection of a burst
  47. GRB 230510A: Swift-BAT refined analysis
  48. GRB 230523B: GRBAlpha detection
  49. GRB 230523B: Name correction from GCN Circular 33859
  50. GRB 230523A: Swift/BAT-GUANO detection of a short hard burst
  51. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
  52. IPN triangulation of GRB 230518A (short)
  53. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for Swope candidates: SSS23a, SSS23b and SSS23c
  54. GRB 230518A: Fermi GBM Observation
  55. GRB 230518A: Swift/BAT-GUANO detection
  56. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  57. Improved IPN triangulation of GRB 230512A
  58. IPN triangulation of GRB 230512A
  59. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  60. GRB 230512A: Liverpool Telescope observations
  61. GRB 230512A: Kitab possible afterglow candidate
  62. GRB 230510A: GRBAlpha detection
  63. GRB 230512A: Swift-XRT observations
  64. GRB 230512A: Tiled Swift observations
  65. GRB 230512A: Fermi-LAT detection
  66. GRB 230510A: GIT optical upper limits
  67. GRB 230510A: LCOGT Optical Upper Limit
  68. GRB 230510A: Swift/UVOT Observations
  69. GRB 230510A: Fermi GBM detection
  70. GRB 230510A: Gaoyazi/GOT optical upper limit
  71. GRB 230510A: CALET Gamma-Ray Burst Monitor detection
  72. GRB 230510A: Nanshan/NEXT optical afterglow detection
  73. GRB 230506B: Fermi GBM detection
  74. GRB 230510A: Swift-XRT refined Analysis
  75. GRB 230510A: Enhanced Swift-XRT position
  76. GRB 230506C: Fermi GBM detection
  77. GRB 230510A: Swift detection of a burst
  78. GRB 230506B: Swift/UVOT further analysis
  79. GRB 230506C: Swift-XRT refined Analysis
  80. GRB 230506C: Swift-BAT refined analysis
  81. GRB 230506B: Swift-BAT refined analysis
  82. GRB 230506B: LCOGT Optical Upper Limits
  83. GRB 230506C: Swift/UVOT Upper Limits
  84. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  85. GRB 230506B: Swift-XRT refined Analysis
  86. GRB 230506C: Swift-XRT analysis
  87. GRB 230506C: Candidate afterglow observation by D50
  88. GRB 230506C: TSHAO possible afterglow candidate
  89. GRB 230506B: Swift/UVOT Detection
  90. GRB 230506C: Swift detection of a burst
  91. Swift GRB230506.71: Global MASTER-Net observations report
  92. GRB 230506B: Swift detection of a burst
  93. GRB 230506B: MASTER optical observations
  94. GRB 230506B: Swift detection of a burst
  95. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  96. GRB 230427A: Swift-BAT refined analysis
  97. GRB 230420A: AROMA-N Optical Upper Limit
  98. GRB 230427A: NOT optical upper limit
  99. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  100. GRB 230427A: Swift/UVOT Detection

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