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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. GRB 221009A: Second epoch of NuSTAR data
  2. GRB 221016A: Swift-XRT refined Analysis
  3. GRB 221016A: Fermi GBM observation
  4. GRB 221009A: Armchair Energetics
  5. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  6. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  7. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  8. GRB 221009A: Gamma-ray Detection by SIRI-2
  9. GRB 221006A: Swift-XRT afterglow detection
  10. GRB221009A: optical afterglow measurements from Konkoly Observatory
  11. GRB 221009A: NuSTAR Detection
  12. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
  13. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  14. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  15. GRB 221009A: Continued Swift/XRT observations
  16. Konus-Wind detection of GRB 221009A
  17. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  18. GRB 221009A: Fermi-LAT refined analysis
  19. GRB 221009A: Swift-XRT refined Analysis
  20. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  21. GRB 221008A: Swift-XRT observations
  22. GRB 221006A: Swift-XRT observations
  23. GRB 220930A: Swift-XRT refined Analysis
  24. Fermi-LAT gamma-ray observations of IceCube-220928A
  25. GRB 220924A: Fermi GBM detection
  26. GRB 220921A: Fermi GBM detection
  27. GRB 220921A: Swift-XRT Observations
  28. GRB 220921A: Fermi-LAT detection
  29. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  30. IceCube-220907A: No significant detection in HAWC
  31. GRB 220909A: Fermi GBM observation
  32. GRB 220910A: Fermi GBM observation
  33. GRB 220909A: Swift-XRT observations
  34. GRB 220831A: Gemini-South Infrared Observations
  35. GRB 220907A: Fermi GBM observation
  36. GRB 220907A: Swift-XRT refined Analysis
  37. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  38. GRB 220907A: Swift-XRT position
  39. GRB 220831A: Swift-UVOT Upper Limits
  40. GRB 220831A: Fermi GBM observation
  41. GRB 220831A: Swift-XRT observations
  42. IceCube-220822A: No significant detection in HAWC
  43. GRB 220826A: Fermi GBM observation
  44. GRB 220826A: Swift-XRT refined Analysis
  45. GRB 220825A: Fermi GBM observation
  46. GRB 220826A: iTelescope optical afterglow observations
  47. GRB 220823A: Fermi GBM detection
  48. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  49. Konus-Wind detection of GRB 220813A
  50. GRB 220810A: Further Swift-XRT observations
  51. GRB 220813A: Swift-XRT refined Analysis
  52. GRB 220810A: Swift-XRT observations
  53. GRB 220730A: Fermi GBM detection
  54. GRB 220730A: Swift-XRT afterglow detection
  55. GRB 220730A: Swift-XRT observations
  56. GRB 220715B: Fermi GBM detection
  57. GRB 220715B: Swift-XRT refined Analysis
  58. GRB 220714B: Fermi GBM observation
  59. GRB 220715A: AGILE/MCAL detection
  60. GRB 220714B: Swift-XRT refined Analysis
  61. GRB 220711B: 10.4 m GTC(+EMIR) observations
  62. GRB 220711B: 10.4 m GTC(+EMIR) observations
  63. GRB 220710A: Swift-XRT afterglow detection
  64. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  65. GRB 220711B: GIT optical upper limits
  66. GRB 220711B: Swift-XRT refined Analysis
  67. GRB 220708B: GIT optical upper limits
  68. GRB 220708A: Swift-XRT refined Analysis
  69. GRB 220708B: Swift-XRT afterglow detection
  70. GRB 220706A: Swift-XRT refined Analysis
  71. Alert from the HAWC Burst Monitor HAWC-220702A
  72. GRB 220701A: Swift-XRT refined Analysis
  73. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  74. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  75. IceCube-220629A: No significant detection in HAWC
  76. IceCube-220627A: No significant detection in HAWC
  77. GRB 220627A: Swift-XRT afterglow detection
  78. Konus-Wind detection of GRB 220627A
  79. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  80. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  81. GRB 220627A: Fermi-LAT detection
  82. IceCube-220624A: No significant detection in HAWC
  83. GRB 220623A: GIT optical upper limits.
  84. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  85. GRB 220623A: Swift-XRT refined Analysis
  86. GRB 220623A: iTelescope optical upper limit
  87. GRB 220618A: Fermi GBM detection
  88. GRB 220611A: Continued Gemini Infrared Observations
  89. GRB 220617A: Fermi GBM observation
  90. GRB 220618A: Swift-XRT refined Analysis
  91. GRB 220617A: Swift-XRT observations
  92. GRB 220617A: Fermi-LAT detection
  93. GRB 220611A: Gemini Ks counterpart detection
  94. GRB 220611A: Gemini South Infrared Detection
  95. GRB 220611A: Swift-XRT refined Analysis
  96. GRB 220606A: Fermi GBM observation
  97. GRB 220606B: Fermi GBM Observation
  98. GRB 220606B: Swift follow-up observations
  99. GRB 220528A: Fermi GBM Observation
  100. Konus-Wind observation of GRB 220527A

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