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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"
  1. GRB 220715B: Swift detection of a burst
  2. GRB 220715B: Fermi GBM Final Real-time Localization
  3. GRB 220714B: Swift-BAT refined analysis
  4. GRB 220714B: Fermi GBM observation
  5. GRB 220715A: AGILE/MCAL detection
  6. GRB 220714B: LCO Optical Observations
  7. GRB 220715A: Fermi GBM Final Real-time Localization
  8. GRB 220714B: Swift-XRT refined Analysis
  9. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  10. GRB 220714B: UVOT afterglow discovery
  11. GRB 220714B: Enhanced Swift-XRT position
  12. GRB 220713A: Fermi GBM Final Localization
  13. GRB 220714B: Swift detection of a burst
  14. GRB 220714B: Fermi GBM Final Real-time Localization
  15. GRB 220714A: Possible Swift detection of a burst
  16. GRB 220710A: Swift/UVOT Upper Limits
  17. GRB 220711C: Fermi GBM Observation
  18. Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)
  19. GRB 220711B: 10.4 m GTC(+EMIR) observations
  20. GRB 220711B: 10.4 m GTC(+EMIR) observations
  21. GRB 220710A: Swift-XRT afterglow detection
  22. GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
  23. GRB 220711B, GROND observations
  24. Konus-Wind detection of GRB 220711C
  25. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  26. GRB 220711B: GIT optical upper limits
  27. Fermi trigger No 679248723: Global MASTER-Net observations report
  28. Fermi GRB 220711B: Global MASTER-Net observations report
  29. GRB 220712B: NOT optical afterglow confirmation
  30. GRB 220710A: Swift ToO observations
  31. GRB 220710A: Swift/BAT-GUANO arcminute localization
  32. GRB 220711B: Swift-BAT refined analysis
  33. IPN triangulation of GRB 220711C (short)
  34. GRB 220711B: Swift-XRT refined Analysis
  35. GRB 220711B: Swift/UVOT Upper Limits
  36. GRB 220711B: Enhanced Swift-XRT position
  37. GRB 220711B: Fermi GBM Detection
  38. GRB 220711B: NOT optical observations
  39. GRB 220711B: LCO Optical Upper Limits
  40. GRB 220711B: Swift detection of a burst
  41. GRB 220711B: Fermi GBM Final Real-time Localization
  42. GRB 220707A: AstroSat CZTI detection
  43. GRB 220708B: GIT optical upper limits
  44. GRB 220711A: Fermi GBM Final Real-time Localization
  45. GRB 220708A: Swift-BAT refined analysis
  46. GRB 220708B: T193-OHP optical upper limit
  47. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  48. Konus-Wind detection of GRB 220708B
  49. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  50. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  51. GRB 220708B: Nanshan/NEXT optical upper limits
  52. GRB 220708A: Swift/UVOT Upper Limits
  53. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  54. GRB 220708A: Swift-XRT refined Analysis
  55. GRB 220706A: Swift/UVOT Upper Limits
  56. GRB 220708B: Swift-XRT afterglow detection
  57. GRB 220708A: BOOTES-5/JGT early optical upper limit
  58. GRB 220706A: Swift-BAT refined analysis
  59. GRB 220708A: Enhanced Swift-XRT position
  60. GRB 220708B: Swift ToO observations
  61. GRB 220708B: Swift/BAT-GUANO arcminute localization
  62. GRB 220708A: Swift-XRT observations
  63. GRB 220708A: Swift detection of a burst
  64. GRB 220706A: LCO Optical Upper Limits
  65. GRB 220627A: ATCA detection of radio counterpart
  66. GRB 220706A: Swift-XRT refined Analysis
  67. GRB 220706A, GROND observations
  68. GRB 220706A: Optical observations from NOT
  69. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  70. GRB 220702B: AstroSat CZTI detection
  71. GRB 220706A: Nanshan/NEXT optical upper limits
  72. MAXI GRB220706.73: Global MASTER-Net observations report
  73. GRB 220706A: Enhanced Swift-XRT position
  74. Swift GRB 220706A: Global MASTER-Net observations report
  75. GRB 220706A: Zadko observatory - Gingin optical observations
  76. GRB 220706A: Prompt enhanced Swift-XRT position
  77. GRB 220706A: Swift detection of a burst
  78. GRB 220701A: Swift-BAT refined analysis
  79. GRB220408A: VIRT Optical Upper Limit
  80. GRB220412A: VIRT Optical Upper Limit
  81. GRB220701A: VIRT Optical Upper Limit
  82. GRB 220702B: Fermi GBM Final Localization
  83. GRB 220702A: Fermi GBM Final Localization
  84. GRB 220705A: Fermi GBM Final Localization
  85. Fermi trigger No 678635286: Global MASTER-Net observations report
  86. GRB 220701A: MITSuME Akeno optical upper limits
  87. Alert from the HAWC Burst Monitor HAWC-220702A
  88. GRB 220701A: COATLI Optical Upper Limit
  89. GRB 220701A: AbAO optical upper limit
  90. GRB 220627A: AstroSat CZTI detection
  91. GRB 220701A: Keck/LRIS Optical Upper Limit
  92. GRB 220701A: Swift-XRT refined Analysis
  93. GRB 220701A: LCO Optical Upper Limits
  94. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 220701A: BOOTES-5/JGT early optical upper limit
  96. GRB 220701A: Swift/UVOT Upper Limits
  97. GRB 220701A: Lowell Discovery Telescope Optical Observations
  98. GRB 220701A: Enhanced Swift-XRT position
  99. GRB 200701A: KAIT Optical Upper Limit
  100. GRB 220701A: Swift detection of a burst

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