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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"

21140 results found.

  1. GRB 201216A - further Swift-XRT observations
  2. Fermi-LAT Gamma-ray Observations of IceCube-201222A
  3. Fermi-LAT Gamma-ray Observations of IceCube-201221A
  4. IceCube-201222A: not observable by Fermi-GBM
  5. GRB 201221D: Archival PS1 Imaging of the Putative Host Galaxy
  6. GRB 201221D: Swift/UVOT Upper Limits
  7. GRB 201221D: Lowell Discovery Telescope afterglow observations
  8. IceCube Alert 201222.04: Global MASTER-Net observations report
  9. Swift GRB 201221D: Global MASTER-Net observations report
  10. Fermi GRB 201221E: Global MASTER-Net observations report
  11. GRB 201221D: Nanshan/NEXT early optical upper limit
  12. GRB 201221D: candidate optical counterpart from the NOT
  13. GRB 201221A: Swift/UVOT Upper Limits
  14. GRB 201221C: MASTER optical observtion
  15. IceCube-201221A: not observable by Fermi-GBM
  16. Swift GRB 201221A: Global MASTER-Net observations report
  17. GRB 201209A: Mondy optical observations, afterglow confirmation
  18. GRB 201214A: Swift-XRT afterglow detection
  19. Fermi GRB 201218B: Global MASTER-Net observations report
  20. Fermi GRB 201218A: Global MASTER-Net observations report
  21. GRB 201216C: Liverpool Telescope First Hour Observations
  22. Fermi GRB 201217A: Global MASTER-Net observations report
  23. GRB 201216C: VLT X-shooter spectroscopy and potential high redshift of a VHE-emitting GRB
  24. GRB 201216C: MAGIC detection in very high energy gamma rays
  25. GRB 201216C: Swift/UVOT Upper Limits
  26. GRB 201216C: FRAM-ORM afterglow confirmation
  27. GRB 201216A: Swift-XRT observations
  28. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  29. GRB 201216C: VLT afterglow candidate discovery
  30. GRB 201216A: Swift ToO observations
  31. GRB 201216C: Swift-XRT observations
  32. Swift GRB201216.96: Global MASTER-Net observations report
  33. Fermi GRB 201216A: Global MASTER-Net observations report
  34. GRB 201216A: Swift/BAT-GUANO detection and arcminute localization
  35. Chandra observations of GW170817 at ~3.3 years since merger (Full report)
  36. GRB 201214B: Lowell Discovery Telescope optical observations
  37. VLA observations of GW170817 at ~3.3 years post-merger
  38. GRB 201214B: Swift-XRT observations
  39. Fermi GRB 201215A: Global MASTER-Net observations report
  40. IceCube-201209A: Upper limits from Insight-HXMT/HE observations
  41. GRB 201214A: Swift-XRT observations
  42. GRB 201214B: Swift BAT location of short burst
  43. Fermi GRB 201214B: Global MASTER-Net observations report
  44. GRB 201214B: Swift ToO observations
  45. Potential X-ray KN afterglow from Chandra observations of GW170817 ~3.3 years since merger (3 Epochs of 4)
  46. Long-lasting X-ray emission from GW170817 detected by Chandra
  47. GRB 201214A: Swift ToO observations
  48. Integral GRB201214.26: Global MASTER-Net observations report
  49. GRB 201015A: optical observations and supernova identification
  50. GRB 201203A: Zeiss-1000 (Koshka observatory) optical upper limit
  51. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  52. GRB 200826A: GMOS-N detected source magnitude (Correction)
  53. GRB 201209A: Swift/UVOT Upper Limits
  54. IceCube-201209A: Upper limits from Fermi-GBM Observations
  55. Fermi-LAT Gamma-ray Observations of IceCube-201209A
  56. IceCube Alert 201209.43: Global MASTER-Net observations report
  57. Chandra observations of GW170817 at ~3.3 years since merger (Observation 1 of 4)
  58. GRB 201208A: Swift-XRT afterglow detection
  59. GRB 201208A: LCO observations
  60. GRB 201209A: Xinglong-2.16m likely optical afterglow detection
  61. IceCube-201130A: Optical and NIR Imaging Follow-up by Kanata Telescope
  62. GRB 201209A: KAIT Optical Upper Limit
  63. Swift GRB201209.24: Global MASTER-Net observations report
  64. GRB 201208A: Swift ToO observations
  65. Fermi GRB 201208A: Global MASTER-Net observations report
  66. Fermi GRB 201207A: Global MASTER-Net observations report
  67. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  68. Swift GRB 201203A: Global MASTER-Net observations report
  69. GRB 201203A: Swift-XRT afterglow detection
  70. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  71. GRB 201203A: KAIT Optical Upper Limit
  72. GRB 201203A: DDOTI Observations
  73. GRB 201128B: Swift-XRT observations
  74. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  75. Fermi-LAT Gamma-ray Observations of IceCube-201130A
  76. IceCube-201130A: Not observable by Fermi-GBM
  77. GRB 201201A: DDOTI Observations
  78. Fermi GRB 201201A: Global MASTER-Net observations report
  79. GRB 201128B: Swift ToO observations
  80. Swift-XRT observations of IceCube 201130A
  81. GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
  82. GRB 201128A: Swift/UVOT Upper Limits
  83. IceCube Alert 201130.85: Global MASTER-Net observations report
  84. GRB 201130A: DDOTI Observations
  85. Fermi GRB 201130A: Global MASTER-Net observations report
  86. Baksan Neutrino Observatory Alert 201128.90: Global MASTER-Net observations report
  87. Fermi trigger No 628278856: Global MASTER-Net observations report
  88. GRB 201128A: DDOTI Observations
  89. Fermi trigger No 628140709: DDOTI/OAN optical observations report
  90. Fermi trigger No 628140709: Global MASTER-Net observations report
  91. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  92. IceCube Alert 201124.34: Global MASTER-Net observations report
  93. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  94. GRB 200826A: TNG and LBT constraints on a supernova bump
  95. IceCube-201114A: DECam observations and candidate optical counterpart
  96. GRB 201015A L-band observations with e-MERLIN
  97. Fermi-LAT Gamma-ray Observations of IceCube-201120A
  98. Fermi trigger No 627645769: Global MASTER-Net observations report
  99. GRB 201015A radio afterglow with e-MERLIN
  100. Fermi GRB 201121A: Global MASTER-Net observations report

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