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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"

19876 results found.

  1. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  2. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  3. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  4. Swift Trigger 1232465: consistent with noise
  5. GRB 240603B: Swift detection of a possible burst
  6. GRB 240529A: MASTER prompt OT detection
  7. GRB 240529A: OSN optical detection
  8. Swift Trigger 1232465 is not a GRB
  9. GRB 240529A: 1.3m DFOT Optical observations
  10. Konus-Wind detection of GRB 240529A
  11. IPN triangulation of the initial episode of GRB 240529A
  12. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  13. GRB 240529A: Insight-HXMT/HE detection
  14. GRB 240529A: GROWTH-India optical follow-up
  15. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  17. GRB 240529A: Skynet Optical Observations
  18. GRB 240529A: Swift-BAT refined analysis
  19. GRB 240529A: Swift-XRT refined Analysis
  20. GRB240529A: BOOTES-6/DPRT optical detection
  21. GRB 240529A: Swift/UVOT Detection
  22. GRB 240529A: NOT optical observations
  23. GRB 240529A: AstroSat CZTI detection
  24. GRB 240529A: GOTO optical afterglow detection
  25. GRB 240527B: Swift-XRT afterglow detection
  26. GRB 240529A: Enhanced Swift-XRT position
  27. GRB 240529A: Swift detection of a burst with an optical counterpart
  28. Swift GRB240529.12: Global MASTER-Net observations report
  29. GRB 240527B: Fermi-LAT detection
  30. GRB 240523A: Swift-BAT refined analysis
  31. GRB 240523A: Swift-XRT refined Analysis
  32. GRB 240523A: Enhanced Swift-XRT position
  33. GRB 240523A: Swift detection of a burst
  34. GRB 240521B: Fermi GBM Observation
  35. GRB 240513A: Swift-XRT afterglow detection
  36. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  37. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  38. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  39. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  40. GRB 240504A: VZLUSAT-2 detection
  41. GRB 240516A: Swift/UVOT Upper Limits
  42. GRB 240516A: Swift-BAT refined analysis
  43. GRB 240516A ATCA radio observations
  44. IPN triangulation of GRB 240514B (short)
  45. GRB 240513A: Swift ToO observations
  46. GRB 240516A: AstroSat CZTI detection
  47. GRB 240516A: Swift-XRT refined Analysis
  48. GRB 240514E: A possible candidate BD-21 1074
  49. GRB 240516A: Fermi GBM Observation
  50. GRB 240516A: GOTO optical upper limit
  51. GRB 240516A: Swift detection of a burst
  52. Swift GRB240516.15: Global MASTER-Net observations report
  53. GRB 240513A: Swift-XRT observations
  54. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  55. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  57. GRB 240513A: Tiled Swift observations
  58. GRB 240513A: Fermi-LAT detection
  59. GRB 240511A: Fermi GBM Observation
  60. GRB 240511A: Swift-BAT refined analysis
  61. GRB 240511A: J-band observations with WINTER
  62. GRB 240511A: Enhanced Swift-XRT position
  63. GRB 240511A : MITSuME Akeno optical upper limits
  64. GRB 240511A: Swift-XRT refined Analysis
  65. Swift GRB 240511A: Global MASTER-Net observations report
  66. GRB 240511A: Prompt enhanced Swift-XRT position
  67. GRB 240511A: Swift detection of a burst
  68. GRB 240504A: Fermi GBM Observation
  69. IPN triangulation of GRB 240504A
  70. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  71. GRB 240415A 1.3m DFOT Optical upper limit
  72. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  73. LVK S240422ed: Further Swift-XRT followup of three sources
  74. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  75. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  76. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  77. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  78. GRB 240419B: Swift-BAT refined analysis
  79. GRB 240421B: Swift-BAT refined analysis
  80. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  81. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  82. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  83. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  84. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  85. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  86. GRB 240421B: GRBAlpha detection
  87. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  88. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  89. GRB 240419A: Swift-BAT refined analysis
  90. GRB 240418A: Swift-BAT refined analysis
  91. LXT240402A/GRB240402B: Chandra X-ray detection
  92. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  93. GRB 240419B : MITSuME Akeno optical upper limits
  94. GRB 240415B: Swift-XRT observations
  95. GRB 240415A: Swift-XRT refined Analysis
  96. GRB 240421B: AstroSat CZTI detection
  97. GRB240421B: Zadko Observations
  98. Swift GRB 240421B: Global MASTER-Net observations report
  99. GRB 240421B: Fermi GBM Observation
  100. GRB 240421B: Swift-XRT refined Analysis

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