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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"

35434 results found.

  1. EP240416A: Khureltogoot optical upper limit
  2. Improved IPN triangulation of GRB 240411A
  3. GRB 240417A: Fermi GBM Final Real-time Localization
  4. GRB 240415A: Glowbug gamma-ray detection
  5. GRB 240414A: Glowbug gamma-ray detection
  6. GRB 240415B: GECAM-B detection
  7. EP 240416a: Xinglong and NOT decaying optical counterpart
  8. GRB 240415A: Swift-BAT refined analysis
  9. GRB 240411A: Glowbug gamma-ray detection
  10. GRB 240414A: Swift-BAT refined analysis
  11. GRB 240414A: AbAO optical upprer limit
  12. GRB 240415A: Swift/UVOT Detection
  13. GRB 240415A: Fermi GBM Observation
  14. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  15. GRB 240415A: Earliest optical followup with the Kinder observations
  16. GRB 240414A: GMG observation
  17. GRB 240415A: Enhanced Swift-XRT position
  18. GRB 240415B: Swift ToO observations
  19. GRB 240415B: Swift/BAT-GUANO Correction
  20. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  21. GRB 240415A: OHP/T193 optical observations
  22. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  23. GRB 240415A: SAO RAS optical observations
  24. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  25. GRB 240414A: Fermi GBM Observation
  26. Fermi GRB 240415A: Global MASTER-Net observations report
  27. GRB 240415A: Mondy optical transient detection
  28. GRB 240414A: Photometric observation from 2.2m CAHA
  29. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 240414A: Swift/UVOT Detection
  31. LXT 240402A/GRB 240402B: Swift follow-up observations
  32. GRB 240414A: Mondy optical observations
  33. GRB 240414B: Fermi GBM Final Real-time Localization
  34. GRB 240414A: AKO Optical Upper Limit
  35. GRB 240415A: Prompt Swift-XRT observations
  36. GRB 240415A: Swift detection of a burst
  37. GRB 240415A: Fermi GBM Final Real-time Localization
  38. EP240413a: Upper limits from GECAM-B Observation
  39. GRB 240414A: Swift-XRT refined Analysis
  40. GRB240414A : J-band upper limits from WINTER
  41. GRB 240414A: Enhanced Swift-XRT position
  42. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  43. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  44. GRB 240414A: Skynet Optical Afterglow Observations
  45. Swift GRB 240414A: Global MASTER-Net observations report
  46. IPN triangulation of GRB 240410A
  47. IPN triangulation of GRB 240411A
  48. GRB 240414A : MITSuME Akeno optical upper limits
  49. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  50. GRB 240414A : OHP/T193 redshift determination
  51. GRB 240414A : OHP/T193 optical counterpart detection
  52. GRB 240414A: Swift detection of a burst
  53. GRB 240411B: CrAO/ZTSh optical observations
  54. GRB 240411B: Kinder observations with Lulin observatory
  55. GRB 240411B: HiPERCAM/GTC observation
  56. GRB 240411B: Swift-BAT refined analysis
  57. GRB 240411B: Swift-XRT refined Analysis
  58. GRB 240411B: 1.3m DFOT Optical observations
  59. GRB 240411A: GRBAlpha detection
  60. GRB 240411B: OHP/T193 optical observations
  61. GRB 240405A: Glowbug gamma-ray detection
  62. GRB 240411B: Enhanced Swift-XRT position
  63. GRB 240411B: LCO optical afterglow detection
  64. GRB 240411B: Swift detection of a burst
  65. GRB 240408B: GRBAlpha detection
  66. GRB 240411A: Fermi GBM Final Real-time Localization
  67. EP240408a: Upper limits from GECAM-B Observation
  68. GRB 240405A: GRBAlpha detection
  69. GRB 240408B: AstroSat CZTI detection
  70. Fermi GRB 240408A: Global MASTER-Net observations report
  71. GRB 240408A: Fermi GBM Final Real-time Localization
  72. GRB 240407A: BALROG localization (Fermi Trigger 734144396 / GRB 240407042)
  73. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  74. Fermi GRB 240407A: Global MASTER-Net observations report
  75. GRB 240407A: Fermi GBM Final Real-time Localization
  76. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  77. Fermi GRB 240405B: Global MASTER-Net observations report
  78. GRB 240405B: Fermi GBM Final Real-time Localization
  79. GRB 240402C: Glowbug gamma-ray detection
  80. GRB 240405A: Fermi GBM Final Real-time Localization
  81. GRB 240402C: GRBAlpha detection
  82. GRB 240331A: GRBAlpha detection
  83. LXT 240402A/GRB 240402B: GECAM-C refined analysis
  84. GRB 240403B: Glowbug gamma-ray detection
  85. GRB 240403A: Glowbug gamma-ray detection
  86. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  87. Konus-Wind detection of LXT 240402A/GRB 240402B
  88. GRB/FXT 240402B: Kinder optical counterpart candidate
  89. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  90. GRB 240403A: Fermi GBM Detection
  91. LXT 240402A: EP-FXT detection of the X-ray afterglow
  92. Fermi GRB 240404A: Global MASTER-Net observations report
  93. GRB 240404A: Fermi GBM Final Real-time Localization
  94. GRB 240402B: GWAC-F50A optical upper limit
  95. GRB 240402B: GECAM-C detection
  96. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  97. Fermi GRB 240402A: Global MASTER-Net observations report
  98. GRB 240402A: Fermi GBM Final Real-time Localization
  99. IBAS Alert n.10651 not a GRB
  100. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube

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