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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"

6094 results found.

  1. GRB 221022B: Fermi GBM detection
  2. GRB 221021A: Fermi GBM observation
  3. GRB 221017A: Swift-XRT observations
  4. GRB 221009A: Second epoch of NuSTAR data
  5. GRB 221016A: Swift-XRT refined Analysis
  6. GRB 221016A: Fermi GBM observation
  7. GRB 221009A: Armchair Energetics
  8. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  9. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  10. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  11. GRB 221009A: Gamma-ray Detection by SIRI-2
  12. GRB 221006A: Swift-XRT afterglow detection
  13. GRB221009A: optical afterglow measurements from Konkoly Observatory
  14. GRB 221009A: NuSTAR Detection
  15. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
  16. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  17. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  18. GRB 221009A: Continued Swift/XRT observations
  19. Konus-Wind detection of GRB 221009A
  20. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  21. GRB 221009A: Fermi-LAT refined analysis
  22. GRB 221009A: Swift-XRT refined Analysis
  23. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  24. GRB 221008A: Swift-XRT observations
  25. GRB 221006A: Swift-XRT observations
  26. GRB 220930A: Swift-XRT refined Analysis
  27. Fermi-LAT gamma-ray observations of IceCube-220928A
  28. GRB 220924A: Fermi GBM detection
  29. GRB 220921A: Fermi GBM detection
  30. GRB 220921A: Swift-XRT Observations
  31. GRB 220921A: Fermi-LAT detection
  32. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  33. IceCube-220907A: No significant detection in HAWC
  34. GRB 220909A: Fermi GBM observation
  35. GRB 220910A: Fermi GBM observation
  36. GRB 220909A: Swift-XRT observations
  37. GRB 220831A: Gemini-South Infrared Observations
  38. GRB 220907A: Fermi GBM observation
  39. GRB 220907A: Swift-XRT refined Analysis
  40. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  41. GRB 220907A: Swift-XRT position
  42. GRB 220831A: Swift-UVOT Upper Limits
  43. GRB 220831A: Fermi GBM observation
  44. GRB 220831A: Swift-XRT observations
  45. IceCube-220822A: No significant detection in HAWC
  46. GRB 220826A: Fermi GBM observation
  47. GRB 220826A: Swift-XRT refined Analysis
  48. GRB 220825A: Fermi GBM observation
  49. GRB 220826A: iTelescope optical afterglow observations
  50. GRB 220823A: Fermi GBM detection
  51. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  52. Konus-Wind detection of GRB 220813A
  53. GRB 220810A: Further Swift-XRT observations
  54. GRB 220813A: Swift-XRT refined Analysis
  55. GRB 220810A: Swift-XRT observations
  56. GRB 220730A: Fermi GBM detection
  57. GRB 220730A: Swift-XRT afterglow detection
  58. GRB 220730A: Swift-XRT observations
  59. GRB 220715B: Fermi GBM detection
  60. GRB 220715B: Swift-XRT refined Analysis
  61. GRB 220714B: Fermi GBM observation
  62. GRB 220715A: AGILE/MCAL detection
  63. GRB 220714B: Swift-XRT refined Analysis
  64. GRB 220711B: 10.4 m GTC(+EMIR) observations
  65. GRB 220711B: 10.4 m GTC(+EMIR) observations
  66. GRB 220710A: Swift-XRT afterglow detection
  67. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  68. GRB 220711B: GIT optical upper limits
  69. GRB 220711B: Swift-XRT refined Analysis
  70. GRB 220708B: GIT optical upper limits
  71. GRB 220708A: Swift-XRT refined Analysis
  72. GRB 220708B: Swift-XRT afterglow detection
  73. GRB 220706A: Swift-XRT refined Analysis
  74. Alert from the HAWC Burst Monitor HAWC-220702A
  75. GRB 220701A: Swift-XRT refined Analysis
  76. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  77. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  78. IceCube-220629A: No significant detection in HAWC
  79. IceCube-220627A: No significant detection in HAWC
  80. GRB 220627A: Swift-XRT afterglow detection
  81. Konus-Wind detection of GRB 220627A
  82. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  83. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  84. GRB 220627A: Fermi-LAT detection
  85. IceCube-220624A: No significant detection in HAWC
  86. GRB 220623A: GIT optical upper limits.
  87. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  88. GRB 220623A: Swift-XRT refined Analysis
  89. GRB 220623A: iTelescope optical upper limit
  90. GRB 220618A: Fermi GBM detection
  91. GRB 220611A: Continued Gemini Infrared Observations
  92. GRB 220617A: Fermi GBM observation
  93. GRB 220618A: Swift-XRT refined Analysis
  94. GRB 220617A: Swift-XRT observations
  95. GRB 220617A: Fermi-LAT detection
  96. GRB 220611A: Gemini Ks counterpart detection
  97. GRB 220611A: Gemini South Infrared Detection
  98. GRB 220611A: Swift-XRT refined Analysis
  99. GRB 220606A: Fermi GBM observation
  100. GRB 220606B: Fermi GBM Observation

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