Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. See news and announcements

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"

26344 results found.

  1. GRB 210708A: Swift-BAT refined analysis
  2. Fermi GBM Sub-Threshold Detection of GRB 210708A
  3. Fermi GBM Sub-Threshold Detection of GRB 210707A
  4. IceCube-210629A - Spectroscopic observation of AT2021osi
  5. GRB 210708A: Swift-XRT refined Analysis
  6. GECAM detection of a short burst from SGR 1935+2154
  7. GRB 210707A: A long GRB detected by INTEGRAL
  8. GRB 210708A: Swift detection of a burst
  9. Fermi trigger No 647271699: Global MASTER-Net observations report
  10. GRB 210706A: Fermi GBM observation
  11. GRB 210706A: GIT optical upper limits
  12. GRB 210704A: OAJ T80 multi-color detections
  13. GECAM detection of a bright short burst from SGR 1935+2154
  14. GRB 210706A: Swift-XRT afterglow detection
  15. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  16. GRB 210704A: OSIRIS/GTC spectroscopy
  17. GRB 210704A: RATIR optical upper limits
  18. GRB 210704A: Swift/UVOT Upper Limits
  19. GRB 210704A: TNG detection of the optical afterglow candidate
  20. GRB 210704A: Assy optical afterglow candidate
  21. GRB 210704A: DDOTI upper limit
  22. GRB 210704B: Fermi GBM detection
  23. GRB 210704A: possible local hosts
  24. GRB 210704A: Fermi GBM detection
  25. GRB 210704A: Swift-XRT afterglow detection
  26. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  27. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  28. Fermi trigger No 647108723: Global MASTER-Net observations report
  29. Fermi trigger No 647120009: Global MASTER-Net observations report
  30. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  31. GRB 210702A, Swift-BAT refined analysis
  32. GRB 210702A: Chilescope optical observations
  33. GRB 210702A: iTelescope optical afterglow observations
  34. GRB 210702A: Swift-XRT refined Analysis
  35. GRB 210702A: VLT/X-shooter redshift
  36. GRB 210702A: preliminary Swift/UVOT photometry
  37. GRB210702A: MeerLICHT multi-colour photometry
  38. Swift GRB210702.80: Global MASTER-Net OT detection
  39. GRB 210702A: Swift detection of a burst with a bright optical counterpart
  40. IceCube-210629A: Upper limits from a search for additional neutrino events in IceCube
  41. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  42. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  43. GRB 210627B: GECAM detection
  44. GRB 210619B: Sayan observatory 1.6-m telescope observations
  45. GRB 210626A: GIT optical upper limit
  46. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  47. GRB 210626A: Swift-XRT afterglow detection
  48. Fermi trigger No 646322348: Global MASTER-Net observations report
  49. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
  50. GRB210619B: optical afterglow detection from Konkoly Observatory
  51. GRB 210622A: Swift-XRT observations
  52. GRB 210610B: T-CAT optical observations
  53. GRB 210619B: ASIM observation
  54. GRB 210618A: Swift-XRT afterglow detection
  55. GRB 210619B: Even further SAO RAS optical observations
  56. GRB 210619B: Mini-MegaTORTORA early optical observations
  57. GRB 210622A: Fermi GBM detection
  58. GRB 210619B: Further SAO RAS optical observations
  59. GRB 210622A: Swift/BAT-GUANO detection and arcminute localization of a long burst
  60. GRB 210619B: possibility of lensed visible afterglow?
  61. GECAM detection of GRB 210622B
  62. GRB 210619B: AbAO optical observations
  63. Swift Trigger 1057131: detection of a burst from SGR Swift J1555.2-5402
  64. Swift GRB210621.71: Global MASTER-Net observations report
  65. GRB 210619B: iTelescope optical afterglow observation
  66. GRB 210619B: SAO RAS optical observations
  67. GRB 210619B: SEDM Optical Observations
  68. GRB 210619B: REM optical/NIR afterglow detection
  69. GRB 210619B: GIT optical follow-up and confirmation of jet-break
  70. GRB 210619B: Swift-BAT refined analysis
  71. GRB 210619B: Liverpool Telescope First Hour Observations
  72. GRB 210619B: Fermi GBM detection
  73. GRB 210619B: Swift/UVOT Detection
  74. GRB 210619B: Liverpool telescope imaging of a red afterglow
  75. GRB 210619B: Swift-XRT refined Analysis
  76. GRB 210619B: SARA-KP 0.9m Optical Afterglow Detection
  77. GRB 210619B: Enhanced Swift-XRT position
  78. GRB 210619B: iTelescope T18 detection
  79. GECAM detection of GRB 210619B
  80. Swift GRB210619.99: Global MASTER-Net OT detection
  81. GRB 210619B: Swift detection of a bright burst and optical counterpart
  82. Swift GRB210619.99: Global MASTER-Net OT detection
  83. GRB 210619A: BALROG localization (Fermi Trigger 645799548 / GRB 210619532)
  84. GRB 210618A: Swift/UVOT Upper Limits
  85. GRB 210618A: Swift-BAT refined analysis
  86. GRB 210618A: Fermi GBM observation
  87. GRB 210618A: Swift-XRT observations
  88. GRB 210618A: DDOTI upper limit for the optical afterglow
  89. GRB 210618A: Swift detection of a burst
  90. GRB 210610B: Swift/UVOT Detection
  91. GRB 210610A: Swift/UVOT Detection
  92. GRB 210323B: Fermi GBM observation
  93. GRB 210610B: REM optical/NIR observations of the afterglow
  94. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  95. Swift ToO Observations of HAWC transient J0020+3108
  96. GRB 210605B: Swift-XRT afterglow detection
  97. GRB 210610A: Fermi GBM observations
  98. GRB 210610B: Further SAO RAS optical observations
  99. GRB 210610A: SAO RAS optical observations
  100. GRB 210610B: optical photometry of afterglow at INASAN/Simeiz

Advanced

Download all Circulars as a .tar.gz archive:
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