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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. IceCube Astrotrack Bronze 136918_45252263.amon is likely background
  2. Fermi GBM trigger 681633544/220808277 is not a GRB
  3. IceCube Alert 220808.33: Global MASTER-Net observations report
  4. Fermi GBM trigger 681547990 / 220807287 is not a GRB
  5. GRB 220806A: Swift detection of a burst
  6. Swift GRB220806.76: Global MASTER-Net observations report
  7. GRB 220804A: Fermi GBM Final Localization
  8. Fermi trigger No 681271717: Global MASTER-Net observations report
  9. GRB 220803A: AstroSat CZTI detection
  10. Fermi trigger No 681212354: Global MASTER-Net observations report
  11. Konus-Wind detection of GRB 220730A (short)
  12. GRB 220730A: Swift-BAT refined analysis
  13. GRB 220730A: Fermi GBM detection
  14. GRB 220730A: Swift-XRT afterglow detection
  15. GRB 220730A: Swift/UVOT Upper Limits
  16. GRB 220730A: Swift-XRT observations
  17. GRB 220729A: AstroSat CZTI detection
  18. Swift GRB 220730A: Global MASTER-Net observations report
  19. GRB 220730A: Swift detection of a short hard burst
  20. Fermi trigger No 680782656: Global MASTER-Net observations report
  21. Fermi GRB 220728A: Global MASTER-Net observations report
  22. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220728A
  23. GRB 220728A: Fermi GBM Final Real-time Localization
  24. GRB 220726A: Fermi GBM Final Real-time Localization
  25. Fermi trigger No 680421061: Global MASTER-Net observations report
  26. Fermi GRB 220724A: Global MASTER-Net observations report
  27. GRB 220724A: Fermi GBM Final Real-time Localization
  28. GRB 220715B: VIRT Optical Upper Limit
  29. Fermi GRB 220721A: Global MASTER-Net observations report
  30. GRB 220721A: Fermi GBM Final Real-time Localization
  31. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  32. Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
  33. GRB 220715A: CALET Gamma-Ray Burst Monitor detection
  34. GRB 220711B: CALET Gamma-Ray Burst Monitor detection
  35. GRB 220719A: Fermi GBM Final Real-time Localization
  36. GRB 220715B: Swift-BAT refined analysis
  37. GRB220714B: UVOT detections
  38. GRB 220715B: Fermi GBM detection
  39. GRB 220715B: Swift-XRT refined Analysis
  40. GRB 220715B: Swift/UVOT Upper Limits
  41. GRB 220715B: Enhanced Swift-XRT position
  42. GRB 220715B: BOOTES-network optical upper limits
  43. Swift GRB 220715B: Global MASTER-Net observations report
  44. GRB 220715B: Prompt enhanced Swift-XRT position
  45. GRB 220715B: Swift detection of a burst
  46. GRB 220715B: Fermi GBM Final Real-time Localization
  47. GRB 220714B: Swift-BAT refined analysis
  48. GRB 220714B: Fermi GBM observation
  49. GRB 220715A: AGILE/MCAL detection
  50. GRB 220714B: LCO Optical Observations
  51. GRB 220715A: Fermi GBM Final Real-time Localization
  52. GRB 220714B: Swift-XRT refined Analysis
  53. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  54. GRB 220714B: UVOT afterglow discovery
  55. GRB 220714B: Enhanced Swift-XRT position
  56. GRB 220713A: Fermi GBM Final Localization
  57. GRB 220714B: Swift detection of a burst
  58. GRB 220714B: Fermi GBM Final Real-time Localization
  59. GRB 220714A: Possible Swift detection of a burst
  60. GRB 220710A: Swift/UVOT Upper Limits
  61. GRB 220711C: Fermi GBM Observation
  62. Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)
  63. GRB 220711B: 10.4 m GTC(+EMIR) observations
  64. GRB 220711B: 10.4 m GTC(+EMIR) observations
  65. GRB 220710A: Swift-XRT afterglow detection
  66. GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
  67. GRB 220711B, GROND observations
  68. Konus-Wind detection of GRB 220711C
  69. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  70. GRB 220711B: GIT optical upper limits
  71. Fermi trigger No 679248723: Global MASTER-Net observations report
  72. Fermi GRB 220711B: Global MASTER-Net observations report
  73. GRB 220712B: NOT optical afterglow confirmation
  74. GRB 220710A: Swift ToO observations
  75. GRB 220710A: Swift/BAT-GUANO arcminute localization
  76. GRB 220711B: Swift-BAT refined analysis
  77. IPN triangulation of GRB 220711C (short)
  78. GRB 220711B: Swift-XRT refined Analysis
  79. GRB 220711B: Swift/UVOT Upper Limits
  80. GRB 220711B: Enhanced Swift-XRT position
  81. GRB 220711B: Fermi GBM Detection
  82. GRB 220711B: NOT optical observations
  83. GRB 220711B: LCO Optical Upper Limits
  84. GRB 220711B: Swift detection of a burst
  85. GRB 220711B: Fermi GBM Final Real-time Localization
  86. GRB 220707A: AstroSat CZTI detection
  87. GRB 220708B: GIT optical upper limits
  88. GRB 220711A: Fermi GBM Final Real-time Localization
  89. GRB 220708A: Swift-BAT refined analysis
  90. GRB 220708B: T193-OHP optical upper limit
  91. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  92. Konus-Wind detection of GRB 220708B
  93. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  94. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  95. GRB 220708B: Nanshan/NEXT optical upper limits
  96. GRB 220708A: Swift/UVOT Upper Limits
  97. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  98. GRB 220708A: Swift-XRT refined Analysis
  99. GRB 220706A: Swift/UVOT Upper Limits
  100. GRB 220708B: Swift-XRT afterglow detection

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