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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

6828 results found.

  1. IceCube-201221A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  2. GRB 201214A: Swift-XRT afterglow detection
  3. GRB 201214A: 1.3m DFOT, optical upper limits
  4. GRB201216C: No significant detection in HAWC
  5. GRB 201216C: Fermi-LAT upper limit
  6. GRB 201216C: Fermi GBM detection
  7. GRB 201216A: Fermi GBM detection
  8. GRB 201216A: Swift-XRT observations
  9. Chandra observations of GW170817 at ~3.3 years since merger (Full report)
  10. GRB 201214B: Swift-XRT observations
  11. GRB 201214A: Swift-XRT observations
  12. IceCube-201209: No significant detection in HAWC
  13. Potential X-ray KN afterglow from Chandra observations of GW170817 ~3.3 years since merger (3 Epochs of 4)
  14. Long-lasting X-ray emission from GW170817 detected by Chandra
  15. GRB 201203A: 1.3m DFOT, optical upper limits
  16. Fermi-LAT Gamma-ray Observations of IceCube-201209A
  17. Chandra observations of GW170817 at ~3.3 years since merger (Observation 1 of 4)
  18. GRB 201208A: Swift-XRT afterglow detection
  19. GRB 201208A: Fermi GBM observation
  20. IceCube-201209A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  21. GRB 201209A: Swift-XRT refined Analysis
  22. GRB 201208A: Fermi-LAT detection
  23. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  24. GRB 201203A: GROWTH-India Telescope optical upper limit.
  25. GRB 201203A: Swift-XRT afterglow detection
  26. IceCube-201130A: No significant detection in HAWC
  27. IceCube-201130A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  28. GRB 201128B: Swift-XRT observations
  29. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  30. Fermi-LAT Gamma-ray Observations of IceCube-201130A
  31. Swift-XRT observations of IceCube 201130A
  32. GRB 201128A: Swift-XRT refined Analysis
  33. IceCube-201120A in the Cygnus region: No enhanced TeV gamma-ray flux detected by HAWC
  34. Fermi-LAT Gamma-ray Observations of IceCube-201120A
  35. IceCube-201120A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  36. IceCube-201120A: Swift-XRT non-detection of 4FGL J2028.6+4110e
  37. ZTF20acozryr/AT2020yxz (GRB 201103B): SAO RAS optical observations
  38. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  39. Fermi-LAT Gamma-ray Observations of IceCube-201114A
  40. GRB 201116A: NOT optical observations
  41. GRB 201116A: Swift-XRT afterglow detection
  42. IceCube-201115A: No significant detection in HAWC
  43. IceCube-201114A: No significant detection in HAWC
  44. GRB 201116A: Fermi-LAT detection
  45. IceCube-201115A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  46. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  47. Fermi-LAT Gamma-ray Observations of IceCube-201115A
  48. Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
  49. Swift-XRT observations of IceCube 201114A
  50. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  51. ZTF20acozryr (GRB 201103B): GROWTH-India Telescope optical observations
  52. GRB 201109A: Fermi GBM detection
  53. GRB 201104A: Swift-XRT observations
  54. Swift XRT and UVOT detection of ZTF20acozryr/AT2020yxz/GRB201103B
  55. GRB 201015A: Swift-XRT late time observations
  56. GRB 201104B: Swift-XRT refined Analysis
  57. GRB 201105B: Fermi GBM observation
  58. GRB 201104A: Fermi GBM observation
  59. GRB 201104A: Fermi-LAT detection
  60. IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
  61. GRB 201029A: Fermi GBM detection
  62. GRB 201029A: Swift-XRT refined Analysis
  63. GRB 201027A: Swift-XRT refined Analysis
  64. GRB 201026A: Fermi GBM detection
  65. GRB 201026A: Swift-XRT refined Analysis
  66. GRB 201026A: Swift/UVOT Upper Limits
  67. GRB201024A: rebrightening after initial steep decline
  68. GRB 201020B: HCT and GIT continued optical follow-up observations
  69. GRB 201024A: Swift-XRT refined Analysis
  70. GRB 201020B: follow-up observations with Savelli Telescope
  71. GRB 201020B: follow-up observations at Konkoly
  72. IceCube-201021A: No significant detection in HAWC
  73. GRB 201021C: Swift-XRT refined Analysis
  74. GRB 201020B: GROWTH-India Telescope optical observations
  75. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  76. GRB 201020B: Konkoly Obs. optical detection
  77. GRB 201021C: Fermi GBM detection
  78. GRB 201020A: GROWTH-India Telescope late-time optical upper limit
  79. GRB 201014A: 2.0m HCT upper limit
  80. GRB 201020B: Swift-XRT afterglow detection
  81. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  82. Swift-XRT observations of IceCube 201021A
  83. GRB 201020B: Fermi-LAT detection
  84. GRB 201020A: DOAO optical afterglow observations
  85. GRB 201020A: GROWTH-India Telescope optical observations
  86. GRB 201020B: Fermi GBM detection
  87. Alert from the HAWC Burst Monitor HAWC-201019A
  88. GRB 201020A: Swift-XRT refined Analysis
  89. GRB 201020A: Fermi GBM observation
  90. GRB 201014A: SAO RAS optical observations
  91. GRB 201017A: SAO RAS optical observations
  92. GRB 201017A: GROWTH-India optical upper limit
  93. GRB 201013A: 3.6m DOT Optical Observations
  94. GRB 201015A: GROWTH-India Telescope (GIT) upper limit
  95. GRB 201017A: Swift-XRT refined Analysis
  96. GRB 201017A: Fermi GBM detection
  97. GRB 201017A: Xinglong TNT upper limit
  98. GRB 201015A: Swift-XRT refined Analysis
  99. IceCube-201014A: No significant detection in HAWC
  100. GRB 201008A: Swift-XRT afterglow detection

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