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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"

6098 results found.

  1. GRB 200925B: Swift-XRT refined analysis update
  2. GRB 200925B: Swift-XRT refined Analysis
  3. GRB 200925B: OSN Afterglow Candidate Discovery
  4. Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
  5. IceCube-200921A: no significant detection in HAWC observations
  6. GRB 200922A: Swift-XRT refined Analysis
  7. IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  8. GRB 200914A: Swift-XRT further observations
  9. Swift GRB200919.08: Global MASTER-Net observations report
  10. GRB 200917A: GROWTH-India Telescope optical upper limit.
  11. Swift-XRT observations of IceCube 200916A
  12. IceCube-200916A: No significant detection in HAWC
  13. GRB 200917A: Swift-XRT refined Analysis
  14. IceCube-200916A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  15. Fermi-LAT Gamma-ray Observations of IceCube-200916A
  16. Swift-XRT observations of IceCube 200911A
  17. GRB 200914A: Swift-XRT observations
  18. GRB 200914A: Fermi GBM observation
  19. IceCube-200911A: No significant detection in HAWC
  20. Fermi-LAT Gamma-ray Observations of IceCube-200911A and detection of a new gamma-ray source, Fermi J0330.1+3743
  21. IceCube-200911A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  22. GRB 200829A: T100 observations
  23. GRB 200907B: Swift-XRT refined Analysis
  24. GRB 200906A: LBT near-infrared upper limit
  25. GRB 200906A: Swift-XRT refined Analysis
  26. GRB 200906A: Fermi GBM detection
  27. GRB 200903A: Fermi GBM detection
  28. GRB 200901B: Swift-XRT refined Analysis
  29. GRB 200901A: Swift-XRT refined Analysis
  30. GRB 200901A: Fermi GBM observation
  31. GRB 200901A: Swift-XRT observations
  32. GRB 200829A: further SAO RAS optical observations
  33. GRB 200829A: Fermi GBM detection
  34. GRB 200829A: SAO RAS optical observations
  35. GRB 200829A: Swift-XRT refined Analysis
  36. GRB 200826A: Swift-XRT afterglow detection
  37. GRB 200826B: Fermi GBM detection
  38. GRB 200826A: Fermi GBM observation
  39. Swift Trigger 992444 is due to detector noise
  40. IceCube-200806A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  41. Swift Trigger 992444: a possible GRB 200821A
  42. GRB 200819A: Optical Observations from HCT
  43. GRB 200819A: Swift-XRT refined Analysis
  44. Swift Trigger 990358 is due to detector noise
  45. Swift Trigger 989458 is due to detector noise
  46. Alert from the HAWC Burst Monitor HAWC-200814A
  47. IceCube200806A: No significant detection in HAWC
  48. GRB 200809B: Fermi GBM detection
  49. GRB 200809B: Swift-XRT afterglow detection
  50. GRB 200806A: Swift/UVOT Possible Detection
  51. GRB 200806A: Swift-XRT refined Analysis
  52. Fermi-LAT Gamma-ray Observations of IceCube-200806A
  53. GRB 200803A: Fermi GBM detection
  54. GRB 200803A: Swift-XRT afterglow detection
  55. GRB 200803A: Fermi-LAT detection
  56. GRB 200729A: Swift-XRT refined Analysis
  57. GRB 200714E: Swift-XRT afterglow detection
  58. GRB 200716C: Optical observations from HCT
  59. GRB 200716C: Fermi GBM detection
  60. GRB 200716C: Swift-XRT refined analysis correction
  61. GRB 200716C: Fermi-LAT detection
  62. GRB 200716C: Swift-XRT refined Analysis
  63. GRB 200716A: Fermi GBM detection
  64. GRB 200715A: Swift-XRT afterglow detection
  65. GRB 200714E: Fermi GBM observation
  66. GRB 200714E: Swift-XRT observations
  67. GRB 200713A: Swift-XRT refined Analysis
  68. GRB 200711A: Fermi-LAT marginal detection
  69. GRB 200711A: Swift-XRT refined Analysis
  70. GRB 200711A: Fermi GBM detection
  71. Update of alert from the HAWC Burst Monitor HAWC-200709A
  72. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  73. GRB 200709B: Swift-XRT observations
  74. GRB 200630A: Swift-XRT refined Analysis
  75. GRB 200623A: Swift XRT further observations
  76. GRB 200630A: Fermi GBM detection
  77. GRB 200625A: Fermi-LAT detection is likely a flare from PKS 1127-14
  78. GRB 200623A: Swift-XRT observations
  79. GRB 200623A: Fermi GBM observation
  80. IceCube-200620A: No significant detection in HAWC
  81. Fermi-LAT Gamma-ray Observations of IceCube-200620A
  82. GRB 200613A: R-band observations from HCT
  83. GRB 200619A: Fermi GBM observation
  84. GRB 200613A: SAO RAS optical observations
  85. Swift-XRT observations of IceCube 200615A
  86. IceCube-200615A: No significant detection in HAWC
  87. Fermi-LAT Gamma-ray Observations of IceCube-200615A
  88. IceCube-200614A: No significant detection in HAWC
  89. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  90. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  91. IceCube-200614A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  92. GRB 200613A: Swift-XRT afterglow detection
  93. GRB 200613A: Candidate afterglow from OAJ
  94. GRB 200612A: Fermi GBM detection
  95. GRB 200613A: Fermi-LAT detection
  96. GRB 200613A: Fermi GBM observation
  97. GRB 200612A: Swift-XRT refined Analysis
  98. GRB 200530A: Fermi GBM detection
  99. GRB 200530A: Fermi-LAT detection
  100. Fermi-LAT Gamma-ray Observations of IceCube-200530A

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