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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"

6791 results found.

  1. Fermi-LAT gamma-ray observations of IceCube-240229A
  2. GRB 240305C: AstroSat CZTI detection of a short burst
  3. GRB 240303B: Fermi GBM Detection
  4. GRB 240225B: Swift-XRT afterglow detection
  5. GRB 240215A: Swift-XRT afterglow detection
  6. GRB 240225B: further SAO RAS optical observations
  7. Konus-Wind detection of GRB 240225B (long)
  8. GRB 240225B: SAO RAS optical observations
  9. GRB 240225B: NOT optical observations
  10. GRB 240225B: Swift-XRT observations
  11. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  12. Swift BAT Sub-Threshold Detection of EPW20240219aa
  13. GRB 240222A: Swift-XRT refined Analysis
  14. GRB 240222A: Fermi GBM Observation
  15. GRB 240215B: Fermi GBM Observation
  16. GRB 240218A: LBT H-band detection
  17. Konus-Wind detection of GRB 240218A
  18. GRB 240218A: Swift-XRT refined Analysis
  19. GRB 240218A: Fermi GBM Detection
  20. GRB 240215A: Fermi GBM Observation
  21. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  22. GRB 240209A: Fermi GBM observation
  23. GRB 240128A: Further Swift-XRT observations
  24. Fermi-LAT gamma-ray observations of IceCube-240204A
  25. GRB240204A: Swift/UVOT Upper Limits
  26. Konus-Wind detection of GRB 240205B (long / very soft)
  27. GRB 240205B: Fermi GBM Observation
  28. GRB 240204A: Fermi GBM Observation
  29. GRB 240129A: Fermi GBM Observation
  30. GRB 240128A: Swift-XRT observations
  31. GRB 240123B: Fermi GBM Observation
  32. Fermi-LAT gamma-ray observations of IceCube-240123A
  33. GRB 240123A: further SAO RAS optical observations
  34. GRB 240123A: SAO RAS optical observations
  35. GRB 240122A: Swift/UVOT Upper Limits
  36. GRB 240123A: Swift-XRT refined Analysis
  37. GRB 240122A: Swift-XRT afterglow detection
  38. GRB 240118A: Swift-XRT afterglow detection
  39. GRB 240118C: Fermi GBM Observation
  40. GRB 240115A: Fermi GBM Observation
  41. GRB 240118A: Fermi GBM Observation
  42. GRB 240118A: Fermi-LAT detection
  43. GRB 240115B: Fermi GBM Detection
  44. GRB 240112C: Fermi GBM Detection
  45. GRB 240112C: Swift-XRT refined Analysis
  46. GRB 240109A: Fermi GBM Observation
  47. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  48. GRB GRB240101C: Fermi GBM observation
  49. GRB 240101A: 1.3m DFOT optical observations
  50. GRB 240102A: 1.3m DFOT optical upper limit
  51. GRB 240101B: 1.3m DFOT optical upper limit
  52. GRB 231220A: Swift-UVOT upper limit
  53. GRB 240101B: Swift-XRT refined Analysis
  54. GRB 240102A: Swift-XRT refined Analysis
  55. GRB 240101A: Swift-XRT refined Analysis
  56. GRB231230A: Fermi GBM Observation
  57. GRB 231230A: Swift-XRT refined Analysis
  58. GRB 231210B: BOOTES-7 optical upper limit
  59. GRB 231222B: Swift-XRT afterglow detection
  60. GRB 231222B: Fermi GBM Detection
  61. GRB 231222B: Fermi-LAT detection
  62. GRB 231220A: Swift-XRT follow-up observations
  63. GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
  64. GRB 231214B: Fermi GBM observation
  65. GRB 231216A: Swift-XRT refined Analysis
  66. GRB 231216A: GIT optical upper limit
  67. Konus-Wind detection of GRB 231215A
  68. GRB 231215A: Fermi GBM observation
  69. GRB 231215A: Swift-XRT refined Analysis
  70. GRB 231214A: Fermi GBM observation
  71. Konus-Wind detection of GRB 231210B
  72. GRB 231214A: Swift-XRT refined Analysis
  73. GRB 231214A: Fermi-LAT detection
  74. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  75. GRB 231210B: Swift-XRT refined Analysis
  76. GRB 231205B: 1.3m DFOT Optical upper limit
  77. GRB 231205B: Swift-XRT refined Analysis
  78. Fermi-LAT gamma-ray observations of IceCube-231202A
  79. Fermi-LAT daily aperture light curve of T CrB now available
  80. GRB 231203A: Fermi GBM Observation
  81. GRB 231129C: Swift-XRT afterglow detection
  82. GRB 231129B: Swift-XRT observations
  83. GRB 231129C: Fermi-LAT detection
  84. GRB 231129C: Swift-XRT observations
  85. GRB 231129C: Fermi GBM Observation of a very bright GRB
  86. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  87. GRB 231129A: Swift-XRT refined Analysis
  88. Fermi-LAT gamma-ray observations of IceCube-231125A
  89. GRB 231123C: Fermi GBM Observation
  90. GRB 231123B: Fermi GBM Observation
  91. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  92. GRB 231115A: XMM-Newton observation
  93. GRB 231117A: Chandra afterglow detection
  94. GRB 231117A: GTC Near-Infrared Observations
  95. GRB 231118B: Fermi GBM observation
  96. GRB 231118A: Fermi GBM observation
  97. GRB 231117A: Swift-XRT refined Analysis
  98. GRB 231118A: Swift-XRT refined Analysis
  99. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  100. GRB 231117A: GIT optical follow-up

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