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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"

14824 results found.

  1. GRB 240421B: Swift detection of a burst
  2. GRB 240421A: Fermi GBM Final Real-time Localization
  3. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  4. GRB240419A: Skynet Optical Afterglow Analysis
  5. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  6. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  7. EP240420a: EP-WXT detection of a fast X-ray transient
  8. GRB 240419A: REM NIR afterglow detection
  9. GRB 240419B: Swift detection of a burst
  10. GRB 240411B: Swift/UVOT Detection
  11. EP240417a: YAHPT Optical Upper Limits
  12. GRB240418A: YAHPT Upper Limits
  13. GRB 240419A: VLT/UVES redshift of z = 5.178
  14. GRB 240419A: VLT optical afterglow detection
  15. GRB 240419A: Swift detection of a burst
  16. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  17. GRB 240418A: Swift detection of a burst
  18. EP240417a: EP-WXT detection of a fast X-ray transient
  19. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  20. GRB 240417A: Fermi GBM Final Real-time Localization
  21. GRB 240415A: Glowbug gamma-ray detection
  22. GRB 240414A: Glowbug gamma-ray detection
  23. GRB 240415B: GECAM-B detection
  24. GRB 240411A: Glowbug gamma-ray detection
  25. EP240416a: EP-WXT detection of a fast X-ray transient
  26. GRB 240415A: Swift/UVOT Detection
  27. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  28. EP240414a: EP-FXT follow-up observation
  29. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  30. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  31. GRB 240415A: Mondy optical transient detection
  32. GRB 240414A: Swift/UVOT Detection
  33. LXT 240402A/GRB 240402B: Swift follow-up observations
  34. GRB 240414B: Fermi GBM Final Real-time Localization
  35. GRB 240414A: AKO Optical Upper Limit
  36. GRB 240415A: Swift detection of a burst
  37. GRB 240415A: Fermi GBM Final Real-time Localization
  38. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  39. EP240413A: GOTO optical upper limits
  40. GRB 240414A: Skynet Optical Afterglow Observations
  41. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  42. EP240414a: EP-WXT detection of a fast X-ray transient
  43. IPN triangulation of GRB 240411A
  44. GRB 240414A : MITSuME Akeno optical upper limits
  45. EP240413a: EP-WXT detection of a fast X-ray transient
  46. GRB 240414A : OHP/T193 optical counterpart detection
  47. GRB 240414A: Swift detection of a burst
  48. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  49. EP240408a: GSP optical upper limit
  50. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 240411B: 1.3m DFOT Optical observations
  52. GRB 240411A: GRBAlpha detection
  53. GRB 240405A: Glowbug gamma-ray detection
  54. GRB 240411B: LCO optical afterglow detection
  55. GRB 240411B: Swift detection of a burst
  56. GRB 240408B: GRBAlpha detection
  57. GRB 240411A: Fermi GBM Final Real-time Localization
  58. EP240408a: GROND detection of a candidate counterpart
  59. EP240408a: BOOTES-6/DPRT optical upper limit
  60. GRB 240405A: GRBAlpha detection
  61. EP240408a: EP-WXT detection of a fast X-ray transient
  62. Swift Trigger 1220736: detection of 4U 1543-62.
  63. GRB 240408B: AstroSat CZTI detection
  64. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  65. GRB 240408A: Fermi GBM Final Real-time Localization
  66. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  67. GRB 240407A: Fermi GBM Final Real-time Localization
  68. GRB 240405B: Fermi GBM Final Real-time Localization
  69. GRB 240402C: Glowbug gamma-ray detection
  70. GRB 240405A: Fermi GBM Final Real-time Localization
  71. GRB 240402C: GRBAlpha detection
  72. GRB 240331A: GRBAlpha detection
  73. GRB 240403B: Glowbug gamma-ray detection
  74. GRB 240403A: Glowbug gamma-ray detection
  75. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  76. X-ray transient LXT 240402A: WFST optical upper limits​
  77. Konus-Wind detection of LXT 240402A/GRB 240402B
  78. GRB/FXT 240402B: Kinder optical counterpart candidate
  79. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  80. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  81. GRB 240403A: Fermi GBM Detection
  82. X-ray transient LXT240402A: AST3-3 optical upper limits
  83. LXT 240402A: EP-FXT detection of the X-ray afterglow
  84. GRB 240404A: Fermi GBM Final Real-time Localization
  85. GRB 240402B: GECAM-C detection
  86. X-ray transient LXT 240402A: LEIA detection
  87. GRB 240402A: Fermi GBM Final Real-time Localization
  88. Transient EP240315a: J-band observations of AT2024eju with WIRC
  89. X-ray transient EP20240331a: MeerLICHT optical upper limits
  90. GRB 240329A: Glowbug gamma-ray detection
  91. GRB 240324A: AstroSat CZTI detection of a short burst
  92. GRB 240331A: AstroSat CZTI detection
  93. GRB 240329A: AstroSat CZTI detection
  94. GRB 240331A: Fermi GBM Final Real-time Localization
  95. GRB 240329A: GRBAlpha detection
  96. GRB 240329A: Fermi GBM Final Real-time Localization
  97. GRB 240328C: Glowbug gamma-ray detection
  98. GRB 240328B: Fermi GBM Final Real-time Localization
  99. GRB 240328A: Fermi GBM Final Real-time Localization
  100. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event

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