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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"

6405 results found.

  1. GRB 221028A: GIT optical upper limit
  2. GRB 221027B: Swift-XRT refined Analysis
  3. GRB 221027A: Fermi GBM detection
  4. GRB 221027A: Fermi-LAT detection
  5. GRB 221025A: Fermi GBM Observation
  6. GRB 221022A: Swift-XRT observations
  7. GRB 221024A: Swift-XRT refined Analysis
  8. GRB 221023A: Fermi GBM Observation
  9. GRB 221025A: Fermi-LAT detection
  10. GRB 221022A: Fermi GBM detection
  11. GRB 221023A: Fermi-LAT detection
  12. GRB 221022B: Fermi GBM detection
  13. GRB 221021A: Fermi GBM observation
  14. GRB 221017A: Swift-XRT observations
  15. GRB 221009A: Second epoch of NuSTAR data
  16. GRB 221016A: Swift-XRT refined Analysis
  17. GRB 221016A: Fermi GBM observation
  18. GRB 221009A: Armchair Energetics
  19. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  20. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  21. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  22. GRB 221009A: Gamma-ray Detection by SIRI-2
  23. GRB 221006A: Swift-XRT afterglow detection
  24. GRB221009A: optical afterglow measurements from Konkoly Observatory
  25. GRB 221009A: NuSTAR Detection
  26. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
  27. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  28. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  29. GRB 221009A: Continued Swift/XRT observations
  30. Konus-Wind detection of GRB 221009A
  31. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  32. GRB 221009A: Fermi-LAT refined analysis
  33. GRB 221009A: Swift-XRT refined Analysis
  34. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  35. GRB 221008A: Swift-XRT observations
  36. GRB 221006A: Swift-XRT observations
  37. GRB 220930A: Swift-XRT refined Analysis
  38. Fermi-LAT gamma-ray observations of IceCube-220928A
  39. GRB 220924A: Fermi GBM detection
  40. GRB 220921A: Fermi GBM detection
  41. GRB 220921A: Swift-XRT Observations
  42. GRB 220921A: Fermi-LAT detection
  43. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  44. IceCube-220907A: No significant detection in HAWC
  45. GRB 220909A: Fermi GBM observation
  46. GRB 220910A: Fermi GBM observation
  47. GRB 220909A: Swift-XRT observations
  48. GRB 220831A: Gemini-South Infrared Observations
  49. GRB 220907A: Fermi GBM observation
  50. GRB 220907A: Swift-XRT refined Analysis
  51. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  52. GRB 220907A: Swift-XRT position
  53. GRB 220831A: Swift-UVOT Upper Limits
  54. GRB 220831A: Fermi GBM observation
  55. GRB 220831A: Swift-XRT observations
  56. IceCube-220822A: No significant detection in HAWC
  57. GRB 220826A: Fermi GBM observation
  58. GRB 220826A: Swift-XRT refined Analysis
  59. GRB 220825A: Fermi GBM observation
  60. GRB 220826A: iTelescope optical afterglow observations
  61. GRB 220823A: Fermi GBM detection
  62. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  63. Konus-Wind detection of GRB 220813A
  64. GRB 220810A: Further Swift-XRT observations
  65. GRB 220813A: Swift-XRT refined Analysis
  66. GRB 220810A: Swift-XRT observations
  67. GRB 220730A: Fermi GBM detection
  68. GRB 220730A: Swift-XRT afterglow detection
  69. GRB 220730A: Swift-XRT observations
  70. GRB 220715B: Fermi GBM detection
  71. GRB 220715B: Swift-XRT refined Analysis
  72. GRB 220714B: Fermi GBM observation
  73. GRB 220715A: AGILE/MCAL detection
  74. GRB 220714B: Swift-XRT refined Analysis
  75. GRB 220711B: 10.4 m GTC(+EMIR) observations
  76. GRB 220711B: 10.4 m GTC(+EMIR) observations
  77. GRB 220710A: Swift-XRT afterglow detection
  78. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  79. GRB 220711B: GIT optical upper limits
  80. GRB 220711B: Swift-XRT refined Analysis
  81. GRB 220708B: GIT optical upper limits
  82. GRB 220708A: Swift-XRT refined Analysis
  83. GRB 220708B: Swift-XRT afterglow detection
  84. GRB 220706A: Swift-XRT refined Analysis
  85. Alert from the HAWC Burst Monitor HAWC-220702A
  86. GRB 220701A: Swift-XRT refined Analysis
  87. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  88. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  89. IceCube-220629A: No significant detection in HAWC
  90. IceCube-220627A: No significant detection in HAWC
  91. GRB 220627A: Swift-XRT afterglow detection
  92. Konus-Wind detection of GRB 220627A
  93. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  94. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  95. GRB 220627A: Fermi-LAT detection
  96. IceCube-220624A: No significant detection in HAWC
  97. GRB 220623A: GIT optical upper limits.
  98. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  99. GRB 220623A: Swift-XRT refined Analysis
  100. GRB 220623A: iTelescope optical upper limit

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