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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"

32130 results found.

  1. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  2. GRB 240415A: Earliest optical followup with the Kinder observations
  3. GRB 240414A: GMG observation
  4. GRB 240415A: Enhanced Swift-XRT position
  5. GRB 240415B: Swift ToO observations
  6. GRB 240415B: Swift/BAT-GUANO Correction
  7. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  8. GRB 240415A: OHP/T193 optical observations
  9. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  10. GRB 240415A: SAO RAS optical observations
  11. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  12. GRB 240414A: Fermi GBM Observation
  13. Fermi GRB 240415A: Global MASTER-Net observations report
  14. GRB 240415A: Mondy optical transient detection
  15. GRB 240414A: Photometric observation from 2.2m CAHA
  16. GRB 240414A: Swift/UVOT Detection
  17. LXT 240402A/GRB 240402B: Swift follow-up observations
  18. GRB 240414A: Mondy optical observations
  19. GRB 240414B: Fermi GBM Final Real-time Localization
  20. GRB 240414A: AKO Optical Upper Limit
  21. GRB 240415A: Prompt Swift-XRT observations
  22. GRB 240415A: Swift detection of a burst
  23. GRB 240415A: Fermi GBM Final Real-time Localization
  24. EP240413a: Upper limits from GECAM-B Observation
  25. GRB 240414A: Swift-XRT refined Analysis
  26. GRB240414A : J-band upper limits from WINTER
  27. GRB 240414A: Enhanced Swift-XRT position
  28. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  29. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  30. GRB 240414A: Skynet Optical Afterglow Observations
  31. Swift GRB 240414A: Global MASTER-Net observations report
  32. IPN triangulation of GRB 240410A
  33. IPN triangulation of GRB 240411A
  34. GRB 240414A : MITSuME Akeno optical upper limits
  35. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  36. GRB 240414A : OHP/T193 redshift determination
  37. GRB 240414A : OHP/T193 optical counterpart detection
  38. GRB 240414A: Swift detection of a burst
  39. GRB 240411B: CrAO/ZTSh optical observations
  40. GRB 240411B: Kinder observations with Lulin observatory
  41. GRB 240411B: HiPERCAM/GTC observation
  42. GRB 240411B: Swift-BAT refined analysis
  43. GRB 240411B: Swift-XRT refined Analysis
  44. GRB 240411B: 1.3m DFOT Optical observations
  45. GRB 240411A: GRBAlpha detection
  46. GRB 240411B: OHP/T193 optical observations
  47. GRB 240405A: Glowbug gamma-ray detection
  48. GRB 240411B: Enhanced Swift-XRT position
  49. GRB 240411B: LCO optical afterglow detection
  50. GRB 240411B: Swift detection of a burst
  51. GRB 240408B: GRBAlpha detection
  52. GRB 240411A: Fermi GBM Final Real-time Localization
  53. EP240408a: Upper limits from GECAM-B Observation
  54. GRB 240405A: GRBAlpha detection
  55. GRB 240408B: AstroSat CZTI detection
  56. Fermi GRB 240408A: Global MASTER-Net observations report
  57. GRB 240408A: Fermi GBM Final Real-time Localization
  58. GRB 240407A: BALROG localization (Fermi Trigger 734144396 / GRB 240407042)
  59. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  60. Fermi GRB 240407A: Global MASTER-Net observations report
  61. GRB 240407A: Fermi GBM Final Real-time Localization
  62. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  63. Fermi GRB 240405B: Global MASTER-Net observations report
  64. GRB 240405B: Fermi GBM Final Real-time Localization
  65. GRB 240402C: Glowbug gamma-ray detection
  66. GRB 240405A: Fermi GBM Final Real-time Localization
  67. GRB 240402C: GRBAlpha detection
  68. GRB 240331A: GRBAlpha detection
  69. LXT 240402A/GRB 240402B: GECAM-C refined analysis
  70. GRB 240403B: Glowbug gamma-ray detection
  71. GRB 240403A: Glowbug gamma-ray detection
  72. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  73. Konus-Wind detection of LXT 240402A/GRB 240402B
  74. GRB/FXT 240402B: Kinder optical counterpart candidate
  75. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  76. GRB 240403A: Fermi GBM Detection
  77. LXT 240402A: EP-FXT detection of the X-ray afterglow
  78. Fermi GRB 240404A: Global MASTER-Net observations report
  79. GRB 240404A: Fermi GBM Final Real-time Localization
  80. GRB 240402B: GWAC-F50A optical upper limit
  81. GRB 240402B: GECAM-C detection
  82. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  83. Fermi GRB 240402A: Global MASTER-Net observations report
  84. GRB 240402A: Fermi GBM Final Real-time Localization
  85. IBAS Alert n.10651 not a GRB
  86. GRB 240329A: Glowbug gamma-ray detection
  87. GRB 240324A: AstroSat CZTI detection of a short burst
  88. GRB 240331A: AstroSat CZTI detection
  89. GRB 240329A: AstroSat CZTI detection
  90. GRB 240331A: Fermi GBM Final Real-time Localization
  91. GRB 240329A: GRBAlpha detection
  92. Fermi GRB 240329A: Global MASTER-Net observations report
  93. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  94. GRB 240329A: Fermi GBM Final Real-time Localization
  95. Fermi GRB 240328B: Global MASTER-Net observations report
  96. Fermi GRB 240328A: Global MASTER-Net observations report
  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. X-ray transient EP 240315a: Second epoch Chandra observations

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