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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').

17087 results found.

  1. Swift GRB 240511A: Global MASTER-Net observations report
  2. GRB 240511A: Prompt enhanced Swift-XRT position
  3. GRB 240511A: Swift detection of a burst
  4. GRB 240504A: Fermi GBM Observation
  5. IPN triangulation of GRB 240504A
  6. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  7. GRB 240415A 1.3m DFOT Optical upper limit
  8. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  9. LVK S240422ed: Further Swift-XRT followup of three sources
  10. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  11. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  12. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  13. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  14. GRB 240419B: Swift-BAT refined analysis
  15. GRB 240421B: Swift-BAT refined analysis
  16. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  17. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  18. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  19. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  20. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  21. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  22. GRB 240421B: GRBAlpha detection
  23. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  24. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  25. GRB 240419A: Swift-BAT refined analysis
  26. GRB 240418A: Swift-BAT refined analysis
  27. LXT240402A/GRB240402B: Chandra X-ray detection
  28. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  29. GRB 240419B : MITSuME Akeno optical upper limits
  30. GRB 240415B: Swift-XRT observations
  31. GRB 240415A: Swift-XRT refined Analysis
  32. GRB 240421B: AstroSat CZTI detection
  33. GRB240421B: Zadko Observations
  34. Swift GRB 240421B: Global MASTER-Net observations report
  35. GRB 240421B: Fermi GBM Observation
  36. GRB 240421B: Swift-XRT refined Analysis
  37. GRB240421B: BOOTES-5/JGT optical upper limit
  38. GRB 240421B: Swift/UVOT Upper Limits
  39. GRB 240421B: Enhanced Swift-XRT position
  40. GRB 240421B: Swift detection of a burst
  41. GRB240419A: Skynet Optical Afterglow Analysis
  42. GRB 240419B: Swift/UVOT Upper Limits
  43. GRB 240419A: Swift/UVOT Upper Limits
  44. GRB 240419B: Swift-XRT refined Analysis
  45. Swift GRB 240419B: Global MASTER-Net observations report
  46. GRB 240419B: Enhanced Swift-XRT position
  47. Swift GRB 240419A: Global MASTER-Net observations report
  48. GRB 240418A: Swift/UVOT Upper Limits
  49. GRB 240419A: Swift-XRT refined Analysis
  50. GRB 240418A: Swift-XRT refined Analysis
  51. GRB 240419B: Swift detection of a burst
  52. GRB 240411B: Swift/UVOT Detection
  53. GRB240418A: YAHPT Upper Limits
  54. GRB 240419A: Enhanced Swift-XRT position
  55. GRB 240419A: Prompt enhanced Swift-XRT position
  56. GRB 240419A: Swift detection of a burst
  57. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  58. GRB 240418A: Enhanced Swift-XRT position
  59. Swift GRB240418.85: Global MASTER-Net observations report
  60. GRB 240418A: Swift detection of a burst
  61. Improved IPN triangulation of GRB 240411A
  62. GRB 240415A: Glowbug gamma-ray detection
  63. GRB 240414A: Glowbug gamma-ray detection
  64. GRB 240415B: GECAM-B detection
  65. GRB 240415A: Swift-BAT refined analysis
  66. GRB 240411A: Glowbug gamma-ray detection
  67. GRB 240414A: Swift-BAT refined analysis
  68. GRB 240414A: AbAO optical upprer limit
  69. GRB 240415A: Swift/UVOT Detection
  70. GRB 240415A: Fermi GBM Observation
  71. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  72. GRB 240415A: Enhanced Swift-XRT position
  73. GRB 240415B: Swift ToO observations
  74. GRB 240415B: Swift/BAT-GUANO Correction
  75. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  76. GRB 240414A: Fermi GBM Observation
  77. GRB 240414A: Swift/UVOT Detection
  78. LXT 240402A/GRB 240402B: Swift follow-up observations
  79. GRB 240414A: Mondy optical observations
  80. GRB 240415A: Prompt Swift-XRT observations
  81. GRB 240415A: Swift detection of a burst
  82. GRB 240414A: Swift-XRT refined Analysis
  83. GRB 240414A: Enhanced Swift-XRT position
  84. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  85. GRB 240414A: Skynet Optical Afterglow Observations
  86. Swift GRB 240414A: Global MASTER-Net observations report
  87. IPN triangulation of GRB 240410A
  88. IPN triangulation of GRB 240411A
  89. GRB 240414A : MITSuME Akeno optical upper limits
  90. GRB 240414A: Swift detection of a burst
  91. GRB 240411B: Swift-BAT refined analysis
  92. GRB 240411B: Swift-XRT refined Analysis
  93. GRB 240411B: 1.3m DFOT Optical observations
  94. GRB 240411B: Enhanced Swift-XRT position
  95. GRB 240411B: Swift detection of a burst
  96. EP240408A: MASTER optical observations
  97. EP240408a: GROND detection of a candidate counterpart
  98. EP240408a: Swift follow-up observation
  99. Swift Trigger 1220736: detection of 4U 1543-62.
  100. Swift satellite resumes pointed science observations

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