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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"

19938 results found.

  1. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  2. GRB 240504A: VZLUSAT-2 detection
  3. GRB 240516A: Swift/UVOT Upper Limits
  4. GRB 240516A: Swift-BAT refined analysis
  5. GRB 240516A ATCA radio observations
  6. IPN triangulation of GRB 240514B (short)
  7. GRB 240513A: Swift ToO observations
  8. GRB 240516A: AstroSat CZTI detection
  9. GRB 240516A: Swift-XRT refined Analysis
  10. GRB 240514E: A possible candidate BD-21 1074
  11. GRB 240516A: Fermi GBM Observation
  12. GRB 240516A: GOTO optical upper limit
  13. GRB 240516A: Swift detection of a burst
  14. Swift GRB240516.15: Global MASTER-Net observations report
  15. GRB 240513A: Swift-XRT observations
  16. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  18. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  19. GRB 240513A: Tiled Swift observations
  20. GRB 240513A: Fermi-LAT detection
  21. GRB 240511A: Fermi GBM Observation
  22. GRB 240511A: Swift-BAT refined analysis
  23. GRB 240511A: J-band observations with WINTER
  24. GRB 240511A: Enhanced Swift-XRT position
  25. GRB 240511A : MITSuME Akeno optical upper limits
  26. GRB 240511A: Swift-XRT refined Analysis
  27. Swift GRB 240511A: Global MASTER-Net observations report
  28. GRB 240511A: Prompt enhanced Swift-XRT position
  29. GRB 240511A: Swift detection of a burst
  30. GRB 240504A: Fermi GBM Observation
  31. IPN triangulation of GRB 240504A
  32. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  33. GRB 240415A 1.3m DFOT Optical upper limit
  34. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  35. LVK S240422ed: Further Swift-XRT followup of three sources
  36. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  37. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  38. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  39. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  40. GRB 240419B: Swift-BAT refined analysis
  41. GRB 240421B: Swift-BAT refined analysis
  42. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  43. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  44. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  45. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  46. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  47. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  48. GRB 240421B: GRBAlpha detection
  49. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  50. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  51. GRB 240419A: Swift-BAT refined analysis
  52. GRB 240418A: Swift-BAT refined analysis
  53. LXT240402A/GRB240402B: Chandra X-ray detection
  54. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  55. GRB 240419B : MITSuME Akeno optical upper limits
  56. GRB 240415B: Swift-XRT observations
  57. GRB 240415A: Swift-XRT refined Analysis
  58. GRB 240421B: AstroSat CZTI detection
  59. GRB240421B: Zadko Observations
  60. Swift GRB 240421B: Global MASTER-Net observations report
  61. GRB 240421B: Fermi GBM Observation
  62. GRB 240421B: Swift-XRT refined Analysis
  63. GRB240421B: BOOTES-5/JGT optical upper limit
  64. GRB 240421B: Swift/UVOT Upper Limits
  65. GRB 240421B: Enhanced Swift-XRT position
  66. GRB 240421B: Swift detection of a burst
  67. GRB240419A: Skynet Optical Afterglow Analysis
  68. GRB 240419B: Swift/UVOT Upper Limits
  69. GRB 240419A: Swift/UVOT Upper Limits
  70. GRB 240419B: Swift-XRT refined Analysis
  71. Swift GRB 240419B: Global MASTER-Net observations report
  72. GRB 240419B: Enhanced Swift-XRT position
  73. Swift GRB 240419A: Global MASTER-Net observations report
  74. GRB 240418A: Swift/UVOT Upper Limits
  75. GRB 240419A: Swift-XRT refined Analysis
  76. GRB 240418A: Swift-XRT refined Analysis
  77. GRB 240419B: Swift detection of a burst
  78. GRB 240411B: Swift/UVOT Detection
  79. GRB240418A: YAHPT Upper Limits
  80. GRB 240419A: Enhanced Swift-XRT position
  81. GRB 240419A: Prompt enhanced Swift-XRT position
  82. GRB 240419A: Swift detection of a burst
  83. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  84. GRB 240418A: Enhanced Swift-XRT position
  85. Swift GRB240418.85: Global MASTER-Net observations report
  86. GRB 240418A: Swift detection of a burst
  87. Improved IPN triangulation of GRB 240411A
  88. GRB 240415A: Glowbug gamma-ray detection
  89. GRB 240414A: Glowbug gamma-ray detection
  90. GRB 240415B: GECAM-B detection
  91. GRB 240415A: Swift-BAT refined analysis
  92. GRB 240411A: Glowbug gamma-ray detection
  93. GRB 240414A: Swift-BAT refined analysis
  94. GRB 240414A: AbAO optical upprer limit
  95. GRB 240415A: Swift/UVOT Detection
  96. GRB 240415A: Fermi GBM Observation
  97. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  98. GRB 240415A: Enhanced Swift-XRT position
  99. GRB 240415B: Swift ToO observations
  100. GRB 240415B: Swift/BAT-GUANO Correction

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