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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"

18497 results found.

  1. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  3. GRB 240513A: Tiled Swift observations
  4. GRB 240513A: Fermi-LAT detection
  5. GRB 240511A: Fermi GBM Observation
  6. GRB 240511A: Swift-BAT refined analysis
  7. GRB 240511A: J-band observations with WINTER
  8. GRB 240511A: Enhanced Swift-XRT position
  9. GRB 240511A : MITSuME Akeno optical upper limits
  10. GRB 240511A: Swift-XRT refined Analysis
  11. Swift GRB 240511A: Global MASTER-Net observations report
  12. GRB 240511A: Prompt enhanced Swift-XRT position
  13. GRB 240511A: Swift detection of a burst
  14. GRB 240504A: Fermi GBM Observation
  15. IPN triangulation of GRB 240504A
  16. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  17. GRB 240415A 1.3m DFOT Optical upper limit
  18. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  19. LVK S240422ed: Further Swift-XRT followup of three sources
  20. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  21. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  22. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  23. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  24. GRB 240419B: Swift-BAT refined analysis
  25. GRB 240421B: Swift-BAT refined analysis
  26. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  27. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  28. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  29. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  30. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  31. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  32. GRB 240421B: GRBAlpha detection
  33. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  34. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  35. GRB 240419A: Swift-BAT refined analysis
  36. GRB 240418A: Swift-BAT refined analysis
  37. LXT240402A/GRB240402B: Chandra X-ray detection
  38. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  39. GRB 240419B : MITSuME Akeno optical upper limits
  40. GRB 240415B: Swift-XRT observations
  41. GRB 240415A: Swift-XRT refined Analysis
  42. GRB 240421B: AstroSat CZTI detection
  43. GRB240421B: Zadko Observations
  44. Swift GRB 240421B: Global MASTER-Net observations report
  45. GRB 240421B: Fermi GBM Observation
  46. GRB 240421B: Swift-XRT refined Analysis
  47. GRB240421B: BOOTES-5/JGT optical upper limit
  48. GRB 240421B: Swift/UVOT Upper Limits
  49. GRB 240421B: Enhanced Swift-XRT position
  50. GRB 240421B: Swift detection of a burst
  51. GRB240419A: Skynet Optical Afterglow Analysis
  52. GRB 240419B: Swift/UVOT Upper Limits
  53. GRB 240419A: Swift/UVOT Upper Limits
  54. GRB 240419B: Swift-XRT refined Analysis
  55. Swift GRB 240419B: Global MASTER-Net observations report
  56. GRB 240419B: Enhanced Swift-XRT position
  57. Swift GRB 240419A: Global MASTER-Net observations report
  58. GRB 240418A: Swift/UVOT Upper Limits
  59. GRB 240419A: Swift-XRT refined Analysis
  60. GRB 240418A: Swift-XRT refined Analysis
  61. GRB 240419B: Swift detection of a burst
  62. GRB 240411B: Swift/UVOT Detection
  63. GRB240418A: YAHPT Upper Limits
  64. GRB 240419A: Enhanced Swift-XRT position
  65. GRB 240419A: Prompt enhanced Swift-XRT position
  66. GRB 240419A: Swift detection of a burst
  67. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  68. GRB 240418A: Enhanced Swift-XRT position
  69. Swift GRB240418.85: Global MASTER-Net observations report
  70. GRB 240418A: Swift detection of a burst
  71. Improved IPN triangulation of GRB 240411A
  72. GRB 240415A: Glowbug gamma-ray detection
  73. GRB 240414A: Glowbug gamma-ray detection
  74. GRB 240415B: GECAM-B detection
  75. GRB 240415A: Swift-BAT refined analysis
  76. GRB 240411A: Glowbug gamma-ray detection
  77. GRB 240414A: Swift-BAT refined analysis
  78. GRB 240414A: AbAO optical upprer limit
  79. GRB 240415A: Swift/UVOT Detection
  80. GRB 240415A: Fermi GBM Observation
  81. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  82. GRB 240415A: Enhanced Swift-XRT position
  83. GRB 240415B: Swift ToO observations
  84. GRB 240415B: Swift/BAT-GUANO Correction
  85. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  86. GRB 240414A: Fermi GBM Observation
  87. GRB 240414A: Swift/UVOT Detection
  88. LXT 240402A/GRB 240402B: Swift follow-up observations
  89. GRB 240414A: Mondy optical observations
  90. GRB 240415A: Prompt Swift-XRT observations
  91. GRB 240415A: Swift detection of a burst
  92. GRB 240414A: Swift-XRT refined Analysis
  93. GRB 240414A: Enhanced Swift-XRT position
  94. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  95. GRB 240414A: Skynet Optical Afterglow Observations
  96. Swift GRB 240414A: Global MASTER-Net observations report
  97. IPN triangulation of GRB 240410A
  98. IPN triangulation of GRB 240411A
  99. GRB 240414A : MITSuME Akeno optical upper limits
  100. GRB 240414A: Swift detection of a burst

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