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"

19670 results found.

  1. GRB 191019A: Enhanced Swift-XRT position
  2. GRB 191019A: GROND observations
  3. GRB 191019A: Swift-XRT observations
  4. Swift GRB191019.63: Global MASTER-Net observations report
  5. GRB 191019A: MASTER optical observation
  6. GRB 191019A: Swift detection of a burst
  7. GRB 191017B: Swift-BAT refined analysis
  8. GRB 191017B: Swift/UVOT Upper Limits
  9. GRB 191017B: Swift-XRT refined Analysis
  10. GRB 191016A: Swift-XRT afterglow detection
  11. GRB 191016A: Swift/UVOT Detection
  12. GRB 191017B: Enhanced Swift-XRT position
  13. GRB 191017B: Swift detection of a burst
  14. GRB 191016A: early time BOOTES Network and follow-up 1.5m OSN optical observations
  15. GRB 191016A: Swift-BAT refined analysis
  16. GRB 191016A: KAIT Optical Afterglow Confirmation
  17. Swift GRB191016.17: Global MASTER-Net observations report
  18. GRB 191016A: Swift detection of a burst
  19. GRB 191011A: Swift-BAT refined analysis
  20. GRB 191011A: Swift/UVOT Detection
  21. GRB 191011A: RATIR Optical and NIR Observations
  22. GRB 191011A: Fermi GBM observation
  23. GRB 191011A: Swift-XRT refined Analysis
  24. GRB 191011A: Enhanced Swift-XRT position
  25. GRB 191011A: GROND Detection of the Optical/NIR afterglow
  26. GRB 191011A: VLT X-shooter redshift from RRM Observations
  27. Swift GRB191011.19: Global MASTER-Net observations report
  28. Swift GRB191011.19: Global MASTER-Net OT detection
  29. GRB 191011A: Swift detection of a burst with an optical counterpart
  30. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  31. GRB 191004A: CALET Gamma-Ray Burst Monitor detection
  32. GRB 191004B: Swift/UVOT Detection
  33. GRB 191004B: Continued Optical Afterglow Monitoring with LCO
  34. Konus-Wind observation of GRB 191004B
  35. Konus-Wind observation of GRB 191004A
  36. GRB 191004A: Swift/UVOT Detection
  37. GRB 191004A: Optical Detection with LCO
  38. LIGO/Virgo S190930t: Magellan/IMACS imaging of Swift J224718-581442 (AT2019sbk)
  39. LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
  40. LIGO/Virgo S190930t: Swift discovery of Swift J224718-581442 (AT2019sbk): a fading UV transient with an X-ray counterpart
  41. LIGO/Virgo S190930t: Swift J221951-484240 optical photometry of Chilescope observatory
  42. LIGO/Virgo S190930t: SALT optical spectroscopy of Swift J221951-484240
  43. GRB 191004B: Swift-XRT refined Analysis
  44. GRB 191004B: GROND Detection of the Optical/NIR Afterglow
  45. GRB 191004A: GROND Upper limits
  46. GRB 191004B: COATLI Optical Observations
  47. GRB 191004A: Swift-XRT refined Analysis
  48. GRB 191004B: VLT/X-shooter redshift
  49. GRB 191004B: Swift-BAT refined analysis
  50. GRB 191004B: NOT optical photometry
  51. GRB 191004A: Swift-BAT refined analysis
  52. GRB 191004A: NOT optical upper limits
  53. GRB 191004B: Enhanced Swift-XRT position
  54. GRB 191004A: Enhanced Swift-XRT position
  55. GRB 191004B: Optical Afterglow Detection with LCO
  56. Swift GRB191004.9: Global MASTER-Net OT detection
  57. GRB 191004B: Swift detection of a burst with an optical counterpart
  58. GRB 191004A: Swift detection of a burst with an optical detection
  59. Swift GRB191004.75: Global MASTER-Net OT detection
  60. GRB 191001A: Swift-XRT observations
  61. LIGO/Virgo S190930t: J-GEM follow-up observation for Swift J221951-484240
  62. GRB 191001B: Optical Upper Limits with LCO
  63. LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
  64. GRB 191001B: Swift-BAT refined analysis
  65. IceCube-191001A: Candidate Counterparts with the Zwicky Transient Facility
  66. IPN triangulation of GRB 191001A
  67. GRB 191001A: Swift ToO observations
  68. GRB 191001B: Swift detection of a burst
  69. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  70. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  71. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  72. GRB 190926A: AbAO upper optical limit
  73. GRB 190926A: Swift-BAT refined analysis
  74. GRB 190926A: Swift/UVOT Upper Limits
  75. GRB 190926A: KAIT Optical Upper Limit
  76. GRB 190926A: Swift-XRT refined Analysis
  77. GRB 190926A: Enhanced Swift-XRT position
  78. Swift GRB190926.41: Global MASTER-Net observations report
  79. GRB 190926A: Swift detection of a burst
  80. LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
  81. LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
  82. GRB 190919B: Swift/UVOT Upper Limits
  83. GRB 190919B: Swift-XRT observations
  84. GRB 190919B: Swift ToO observations
  85. GRB 190828B: AstroSat CZTI detection
  86. LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
  87. GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
  88. LIGO/Virgo S190910h: no counterpart candidates in the Swift/BAT observations
  89. LIGO/Virgo S190910d: no counterpart candidates in the Swift/BAT Observations
  90. Swift Trigger 924641 is an outburst from MAXI J1807+132
  91. ZTF19abvizsw: No counterpart candidates from Swift/BAT targeted search
  92. GRB 190823A: Swift-XRT afterglow detection
  93. IPN triangulation of GRB 190906A (short)
  94. GRB190829A: Keck LRIS spectroscopic confirmation of the accompanying supernova
  95. Konus-Wind observation of GRB 190829A
  96. Swift XRT Detection of X-ray Emission from ZTF19abvizsw
  97. GRB 190829A: MASTER confirmation of GROND SN
  98. GRB 190829A: Flattening of optical light curve from continued Liverpool Telescope photometry
  99. LIGO/Virgo S190901ap: no counterpart candidates in the Swift/BAT Observations
  100. GRB 190829A: Continued fading inferred from Liverpool Telescope photometry

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