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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"

19164 results found.

  1. Swift Trigger 1235109: consistent with noise and not astrophysical
  2. GRB 240606B: GECAM-B detection a long burst
  3. GRB 240606B: Swift-XRT afterglow detection
  4. Swift GRB240606.15: Global MASTER-Net observations report
  5. GRB 240606B: Swift ToO observations
  6. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  7. Swift Trigger 1235109: a possible GRB 240606A
  8. IPN triangulation of GRB 240531A (short)
  9. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  10. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  12. Swift Trigger 1232465: consistent with noise
  13. GRB 240603B: Swift detection of a possible burst
  14. GRB 240529A: MASTER prompt OT detection
  15. GRB 240529A: OSN optical detection
  16. Swift Trigger 1232465 is not a GRB
  17. GRB 240529A: 1.3m DFOT Optical observations
  18. Konus-Wind detection of GRB 240529A
  19. IPN triangulation of the initial episode of GRB 240529A
  20. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  21. GRB 240529A: Insight-HXMT/HE detection
  22. GRB 240529A: GROWTH-India optical follow-up
  23. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  25. GRB 240529A: Skynet Optical Observations
  26. GRB 240529A: Swift-BAT refined analysis
  27. GRB 240529A: Swift-XRT refined Analysis
  28. GRB240529A: BOOTES-6/DPRT optical detection
  29. GRB 240529A: Swift/UVOT Detection
  30. GRB 240529A: NOT optical observations
  31. GRB 240529A: AstroSat CZTI detection
  32. GRB 240529A: GOTO optical afterglow detection
  33. GRB 240527B: Swift-XRT afterglow detection
  34. GRB 240529A: Enhanced Swift-XRT position
  35. GRB 240529A: Swift detection of a burst with an optical counterpart
  36. Swift GRB240529.12: Global MASTER-Net observations report
  37. GRB 240527B: Fermi-LAT detection
  38. GRB 240523A: Swift-BAT refined analysis
  39. GRB 240523A: Swift-XRT refined Analysis
  40. GRB 240523A: Enhanced Swift-XRT position
  41. GRB 240523A: Swift detection of a burst
  42. GRB 240521B: Fermi GBM Observation
  43. GRB 240513A: Swift-XRT afterglow detection
  44. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  45. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  47. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  48. GRB 240504A: VZLUSAT-2 detection
  49. GRB 240516A: Swift/UVOT Upper Limits
  50. GRB 240516A: Swift-BAT refined analysis
  51. GRB 240516A ATCA radio observations
  52. IPN triangulation of GRB 240514B (short)
  53. GRB 240513A: Swift ToO observations
  54. GRB 240516A: AstroSat CZTI detection
  55. GRB 240516A: Swift-XRT refined Analysis
  56. GRB 240514E: A possible candidate BD-21 1074
  57. GRB 240516A: Fermi GBM Observation
  58. GRB 240516A: GOTO optical upper limit
  59. GRB 240516A: Swift detection of a burst
  60. Swift GRB240516.15: Global MASTER-Net observations report
  61. GRB 240513A: Swift-XRT observations
  62. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  63. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  64. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  65. GRB 240513A: Tiled Swift observations
  66. GRB 240513A: Fermi-LAT detection
  67. GRB 240511A: Fermi GBM Observation
  68. GRB 240511A: Swift-BAT refined analysis
  69. GRB 240511A: J-band observations with WINTER
  70. GRB 240511A: Enhanced Swift-XRT position
  71. GRB 240511A : MITSuME Akeno optical upper limits
  72. GRB 240511A: Swift-XRT refined Analysis
  73. Swift GRB 240511A: Global MASTER-Net observations report
  74. GRB 240511A: Prompt enhanced Swift-XRT position
  75. GRB 240511A: Swift detection of a burst
  76. GRB 240504A: Fermi GBM Observation
  77. IPN triangulation of GRB 240504A
  78. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  79. GRB 240415A 1.3m DFOT Optical upper limit
  80. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  81. LVK S240422ed: Further Swift-XRT followup of three sources
  82. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  83. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  84. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  85. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  86. GRB 240419B: Swift-BAT refined analysis
  87. GRB 240421B: Swift-BAT refined analysis
  88. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  89. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  90. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  91. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  92. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  93. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  94. GRB 240421B: GRBAlpha detection
  95. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  96. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  97. GRB 240419A: Swift-BAT refined analysis
  98. GRB 240418A: Swift-BAT refined analysis
  99. LXT240402A/GRB240402B: Chandra X-ray detection
  100. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO

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