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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"

35958 results found.

  1. IPN triangulation of GRB 220408B
  2. IPN triangulation of GRB 220403C
  3. GRB 220403B: Swift/UVOT Detection
  4. GRB 220408A: Lowell Discovery Telescope Optical Observations
  5. GRB 220408A: Swift-BAT refined analysis
  6. Fermi GRB 220411A: Global MASTER-Net observations report
  7. GRB 220411A: BALROG localization (Fermi Trigger 671354405/ GRB 220411306)
  8. GRB 220411A: Fermi GBM Final Real-time Localization
  9. GRB 220408A: RATIR Optical and NIR Observations
  10. GRB 220403B: 1.3m DFOT Optical upper limit
  11. GRB 220408A: 1.3m DFOT Optical upper limit
  12. GRB 220408A: LOAO, DOAO, and, SAO optical upper limit
  13. GRB 220403C: Swift-XRT observations
  14. GRB 220408A: redshift lower limit estimating
  15. GRB 220408A: NOT optical observations and archival detection
  16. GRB 220408B: AstroSat CZTI detection
  17. GRB 220408A: LCO Optical Afterglow Detection
  18. GRB 220408A: Swift-XRT refined Analysis
  19. GRB 220403C: Swift ToO observations
  20. GRB 220408A: BOOTES-5/JGT optical afterglow detection
  21. Fermi GRB 220408B: Global MASTER-Net observations report
  22. GRB 220408A: GIT optical upper limit
  23. GRB 220408A: Fermi GBM observation
  24. GRB 220408A: Swift/UVOT Detection
  25. GRB 220408B: Fermi GBM Final Localization
  26. GRB 220408A: Xinglong-2.16m optical upper limit
  27. GRB 220408A: Enhanced Swift-XRT position
  28. Chandra upper limit at the location of GRB 220408A
  29. GRB 220408A: KAIT Optical Observations
  30. Fermi GRB 220408A: Global MASTER-Net observations report
  31. GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
  32. GRB 220408A: Fermi GBM Final Real-time Localization
  33. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, SAO RAS, CrAO)
  34. GRB 220403B: Mondy optical upper limit
  35. GRB 220403B: 1.5m OSN optical observation
  36. GRB 220404A: Swift-BAT refined analysis
  37. GRB 220403B: Kitab optical observations
  38. GRB 220405A: Fermi GBM Final Localization
  39. GRB 220403B: Swift-BAT refined analysis
  40. GRB 220404B: Fermi GBM Final Real-time Localization
  41. GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  42. GRB 220403B: Fermi GBM detection
  43. GRB 220404A: Swift detection of a burst
  44. GRB 220403B: Swift-XRT refined Analysis
  45. GRB 220403B: LBT observations
  46. Swift GRB 220403B: Global MASTER-Net observations report
  47. GRB 220403C (or A): Swift/BAT-GUANO detection outside the coded FOV
  48. GRB 220403B: Nanshan/NEXT optical afterglow power-law decay
  49. GRB 220403A: Tautenburg observations
  50. GRB 220403B: optical detection by D50
  51. GRB 220403B: Swift detection of a burst with an optical counterpart
  52. Fermi GRB 220403A: Global MASTER-Net observations report
  53. GRB 220403A: Fermi GBM Final Real-time Localization
  54. GRB 220401A: Swift/BAT-GUANO detection outside the coded FOV
  55. GRB 220401A: Fermi GBM observation
  56. Swift Trigger 1100848 is likely not a GRB
  57. Fermi GRB 220401B: Global MASTER-Net observations report
  58. GRB 220401B: Fermi GBM Final Real-time Localization
  59. GRB 220401A: Fermi GBM Final Localization
  60. Fermi Gamma-ray Burst Monitor trigger 220331776/670444627 is not a GRB
  61. GRB 220331A: Fermi GBM Final Real-time Localization
  62. Fermi GRB 220330A: Global MASTER-Net observations report
  63. GRB 220330A: Fermi GBM Final Real-time Localization
  64. GRB 220325A: GRANDMA observations
  65. GRB 220320A: Detection by VZLUSAT-2
  66. Konus-Wind observation of GRB 220320A
  67. GRB 220325A: Swift/UVOT Upper Limits
  68. GRB 211024B: Host galaxy redshift from X-shooter/VLT
  69. GRB 220325A: Swift-BAT refined analysis
  70. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, TSHAO, AbAO)
  71. GRB 220325A: Tautenburg observations
  72. GRB 220326A: Fermi GBM Final Localization
  73. GRB 220325A: LCO Optical Upper Limits
  74. GRB 220325A: Swift-XRT refined Analysis
  75. GRB 220325A: 1.3m DFOT Optical upper limit
  76. GRB 220325B: Fermi GBM Final Localization
  77. Fermi GBM Sub-Threshold Detection of GRB 220325A
  78. GRB 220325A: Enhanced Swift-XRT position
  79. GRB 220325A: MASTER Global Robotic Net optical observations
  80. GRB 220324A: AstroSat CZTI detection
  81. GRB 220325A: Swift detection of a burst
  82. GRB 220323A: AstroSat CZTI detection
  83. GRB 220319A: GRANDMA observations
  84. GRB 220323A: AGILE/MCAL detection
  85. IPN triangulation of GRB 220320A
  86. GRB 220323A: Fermi GBM Final Real-time Localization
  87. GRB 220319A: Swift-BAT refined analysis
  88. GRB 220316A: AstroSat CZTI detection
  89. GRB 220320A: AstroSat CZTI detection
  90. GRB 220317A: Fermi GBM detection
  91. GRB 220321A: Fermi GBM Final Localization
  92. GRB 220319A: MITSuME Akeno optical upper limits
  93. GRB 220319A: LCO Optical Upper Limit
  94. GRB 220319A: Mondy optical uper limit
  95. GRB 220319A: Swift-XRT refined Analysis
  96. GRB 220319A: Enhanced Swift-XRT position
  97. GRB 220319A: MASTER Global Robotic Net optical observations
  98. GRB 220319A: Swift detection of a burst
  99. GRB 220317A: Swift/BAT-GUANO detection outside the coded FOV
  100. GRB 220310A: MITSuME Akeno optical observation

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