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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').

17080 results found.

  1. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  2. LVK S240422ed: Further Swift-XRT followup of three sources
  3. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  4. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  5. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  6. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  7. GRB 240419B: Swift-BAT refined analysis
  8. GRB 240421B: Swift-BAT refined analysis
  9. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  10. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  11. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  12. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  13. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  14. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  15. GRB 240421B: GRBAlpha detection
  16. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  17. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  18. GRB 240419A: Swift-BAT refined analysis
  19. GRB 240418A: Swift-BAT refined analysis
  20. LXT240402A/GRB240402B: Chandra X-ray detection
  21. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  22. GRB 240419B : MITSuME Akeno optical upper limits
  23. GRB 240415B: Swift-XRT observations
  24. GRB 240415A: Swift-XRT refined Analysis
  25. GRB 240421B: AstroSat CZTI detection
  26. GRB240421B: Zadko Observations
  27. Swift GRB 240421B: Global MASTER-Net observations report
  28. GRB 240421B: Fermi GBM Observation
  29. GRB 240421B: Swift-XRT refined Analysis
  30. GRB240421B: BOOTES-5/JGT optical upper limit
  31. GRB 240421B: Swift/UVOT Upper Limits
  32. GRB 240421B: Enhanced Swift-XRT position
  33. GRB 240421B: Swift detection of a burst
  34. GRB240419A: Skynet Optical Afterglow Analysis
  35. GRB 240419B: Swift/UVOT Upper Limits
  36. GRB 240419A: Swift/UVOT Upper Limits
  37. GRB 240419B: Swift-XRT refined Analysis
  38. Swift GRB 240419B: Global MASTER-Net observations report
  39. GRB 240419B: Enhanced Swift-XRT position
  40. Swift GRB 240419A: Global MASTER-Net observations report
  41. GRB 240418A: Swift/UVOT Upper Limits
  42. GRB 240419A: Swift-XRT refined Analysis
  43. GRB 240418A: Swift-XRT refined Analysis
  44. GRB 240419B: Swift detection of a burst
  45. GRB 240411B: Swift/UVOT Detection
  46. GRB240418A: YAHPT Upper Limits
  47. GRB 240419A: Enhanced Swift-XRT position
  48. GRB 240419A: Prompt enhanced Swift-XRT position
  49. GRB 240419A: Swift detection of a burst
  50. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  51. GRB 240418A: Enhanced Swift-XRT position
  52. Swift GRB240418.85: Global MASTER-Net observations report
  53. GRB 240418A: Swift detection of a burst
  54. Improved IPN triangulation of GRB 240411A
  55. GRB 240415A: Glowbug gamma-ray detection
  56. GRB 240414A: Glowbug gamma-ray detection
  57. GRB 240415B: GECAM-B detection
  58. GRB 240415A: Swift-BAT refined analysis
  59. GRB 240411A: Glowbug gamma-ray detection
  60. GRB 240414A: Swift-BAT refined analysis
  61. GRB 240414A: AbAO optical upprer limit
  62. GRB 240415A: Swift/UVOT Detection
  63. GRB 240415A: Fermi GBM Observation
  64. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  65. GRB 240415A: Enhanced Swift-XRT position
  66. GRB 240415B: Swift ToO observations
  67. GRB 240415B: Swift/BAT-GUANO Correction
  68. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  69. GRB 240414A: Fermi GBM Observation
  70. GRB 240414A: Swift/UVOT Detection
  71. LXT 240402A/GRB 240402B: Swift follow-up observations
  72. GRB 240414A: Mondy optical observations
  73. GRB 240415A: Prompt Swift-XRT observations
  74. GRB 240415A: Swift detection of a burst
  75. GRB 240414A: Swift-XRT refined Analysis
  76. GRB 240414A: Enhanced Swift-XRT position
  77. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  78. GRB 240414A: Skynet Optical Afterglow Observations
  79. Swift GRB 240414A: Global MASTER-Net observations report
  80. IPN triangulation of GRB 240410A
  81. IPN triangulation of GRB 240411A
  82. GRB 240414A : MITSuME Akeno optical upper limits
  83. GRB 240414A: Swift detection of a burst
  84. GRB 240411B: Swift-BAT refined analysis
  85. GRB 240411B: Swift-XRT refined Analysis
  86. GRB 240411B: 1.3m DFOT Optical observations
  87. GRB 240411B: Enhanced Swift-XRT position
  88. GRB 240411B: Swift detection of a burst
  89. EP240408A: MASTER optical observations
  90. EP240408a: GROND detection of a candidate counterpart
  91. EP240408a: Swift follow-up observation
  92. Swift Trigger 1220736: detection of 4U 1543-62.
  93. Swift satellite resumes pointed science observations
  94. GRB 240318A: Fermi GBM Observation
  95. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  96. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  97. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  98. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  99. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  100. GRB 240317B: Fermi GBM Observation

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