Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

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. Fermi GRB 201120B: Global MASTER-Net observations report
  2. IceCube-201120A: Upper limits from Fermi-GBM Observations
  3. Fermi trigger No 627557935: Global MASTER-Net observations report
  4. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  5. IceCube Alert 201120.41: Global MASTER-Net observations report
  6. ZTF20acozryr/AT2020yxz (GRB 201103B): SAO RAS optical observations
  7. ZTF20acozryr/AT2020yxz (GRB 201103B): correction to the GCN #28883 CrAO/ZTSh optical observations
  8. Fermi trigger No 627438255: Global MASTER-Net observations report
  9. Fermi-LAT Gamma-ray Observations of IceCube-201114A
  10. GRB 201116A: NOT optical observations
  11. GRB 201116A: Swift-XRT afterglow detection
  12. GRB 201116A: OSN Afterglow Candidate
  13. IceCube Alert 201115.67: Global MASTER-Net observations report
  14. Fermi trigger No 627198169: Global MASTER-Net observations report
  15. GRB 201116A: Tiled Swift observations
  16. LAT GRB201116.03: Global MASTER-Net observations report
  17. IceCube Alert 201115.09: Global MASTER-Net observations report
  18. Fermi-LAT Gamma-ray Observations of IceCube-201115A
  19. Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
  20. IceCube-201114A: Upper limits from Fermi GBM Observations
  21. VLASS identifies possible radio counterparts to IceCube-201115A, including a bright BL Lac candidate
  22. Swift-XRT observations of IceCube 201114A
  23. IceCube Alert 201114.63: Global MASTER-Net observations report
  24. ZTF20acozryr/AT2020yxz (GRB 201103B): CrAO/ZTSh optical observations
  25. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  26. ZTF20acozryr/AT2020yxz (GRB 201103B): Mondy continued optical observations
  27. Fermi GRB 201111A: Global MASTER-Net observations report
  28. ZTF20acozryr/AT2020yxz (GRB 201103B): Flattening of the optical light curve
  29. ZTF20acozryr (GRB 201103B): GROWTH-India Telescope optical observations
  30. ZTF20acozryr/AT2020yxz (GRB 201103B): Mondy, Kitab, TSHAO optical observations
  31. GRB 201104B: continued TSHAO optical observation
  32. Fermi GRB 201109A: Global MASTER-Net observations report
  33. Fermi GRB 201108A: Global MASTER-Net observations report
  34. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  35. GRB 201103B: GMG observation (2nd epoch)
  36. ZTF20acozryr/AT2020yxz (GRB 201103B): Assy optical observations
  37. GRB 201104B: 1.3m DFOT optical observations
  38. GRB 201104A: Swift-XRT observations
  39. Swift XRT and UVOT detection of ZTF20acozryr/AT2020yxz/GRB201103B
  40. GRB 201015A: Swift-XRT late time observations
  41. GRB 201104B: Kitab optical observations
  42. GRB 201103B (ZTF20acozryr/AT2020yxz): Xinglong-2.16m optical observations
  43. Fermi trigger No 626247072: Global MASTER-Net observations report
  44. GRB 201104B: Swift/UVOT Detection
  45. Correcton to GCN 28848: Swift observes ZTF20acozryr
  46. GRB 201104C: Swift ToO observations
  47. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  48. GRB 201104A: Tiled Swift observations
  49. GRB 201104B: Swift/UVOT Detection
  50. Fermi GRB 201104A: Global MASTER-Net observations report
  51. Fermi GRB 201103A: Global MASTER-Net observations report
  52. Swift GRB 201031A: Global MASTER-Net observations report
  53. Fermi GRB 201031B: Global MASTER-Net observations report
  54. IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
  55. Swift GRB 201029A: Global MASTER-Net observations report
  56. GRB 201029A: Swift/UVOT Upper Limits
  57. Fermi trigger No 625695596: Global MASTER-Net observations report
  58. GRB 201027A: Swift/UVOT Upper Limits
  59. Baksan Neutrino Observatory Alert 201027.41: Global MASTER-Net observations report
  60. GRB 201026A: Swift/UVOT Upper Limits
  61. Swift GRB201027.05: Global MASTER-Net observations report
  62. GRB 201026A: NanShan/NEXT-0.6m optical upper limit
  63. GRB 201026A: NOT optical upper limits
  64. Swift GRB201026.94: Global MASTER-Net observations report
  65. GRB 201024A: 1.3m DFOT optical observations
  66. GRB 201020B: 1.3m DFOT continued optical follow-up observations
  67. GRB201024A: rebrightening after initial steep decline
  68. GRB 201020B: HCT and GIT continued optical follow-up observations
  69. GRB 201024A: Swift/UVOT Detection
  70. GRB 201020B: follow-up observations with Savelli Telescope
  71. GRB 201020B: 1.3m DFOT optical observations
  72. GRB 201024A: VIRT optical observations
  73. GRB 201020B: follow-up observations at Konkoly
  74. GRB 201020B: continued Mondy optical observations
  75. GRB 201020B: Redshift from GTC/OSIRIS
  76. GRB 201024A: Redshift from GTC/OSIRIS
  77. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  78. Swift GRB201024.12: Global MASTER-Net observations report
  79. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  80. GRB 201020B: GROWTH-India Telescope optical observations
  81. Baksan Neutrino Observatory Alert 201022.66: Global MASTER-Net observations report
  82. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  83. Swift-XRT observations of IceCube 201021A (2)
  84. GRB 201021C: Swift/UVOT Detection
  85. GRB 201020B: Swift/UVOT Detection
  86. GRB 201020A: Swift/UVOT Observations
  87. GRB 201014A: 2.0m HCT upper limit
  88. GRB 201020B: Swift-XRT afterglow detection
  89. GRB 201020A: VIRT optical observations
  90. IceCube-201021A: Upper limits from Fermi-GBM Observations
  91. HAWC-201019A: not observable by Fermi-GBM
  92. Swift GRB201021.85: Global MASTER-Net observations report
  93. MAXI GRB201021.68: Global MASTER-Net observations report
  94. GRB200826A: GMOS-N detection of a supernova bump
  95. GRB 201020B: Mondy optical observations
  96. Swift-XRT observations of IceCube 201021A
  97. IceCube Alert 201021.28: Global MASTER-Net observations report
  98. GRB 201015A: SAO RAS optical observations
  99. GRB 201020B: Swift ToO observations
  100. GRB 201020B: Nanshan/NEXT optical afterglow confirmation

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov