Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
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"
  1. GRB 220708A: BOOTES-5/JGT early optical upper limit
  2. GRB 220706A: Swift-BAT refined analysis
  3. GRB 220708A: Enhanced Swift-XRT position
  4. GRB 220708B: Swift ToO observations
  5. GRB 220708B: Swift/BAT-GUANO arcminute localization
  6. GRB 220708A: Swift-XRT observations
  7. GRB 220708A: Swift detection of a burst
  8. GRB 220706A: LCO Optical Upper Limits
  9. GRB 220627A: ATCA detection of radio counterpart
  10. GRB 220706A: Swift-XRT refined Analysis
  11. GRB 220706A, GROND observations
  12. GRB 220706A: Optical observations from NOT
  13. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  14. GRB 220702B: AstroSat CZTI detection
  15. GRB 220706A: Nanshan/NEXT optical upper limits
  16. MAXI GRB220706.73: Global MASTER-Net observations report
  17. GRB 220706A: Enhanced Swift-XRT position
  18. Swift GRB 220706A: Global MASTER-Net observations report
  19. GRB 220706A: Zadko observatory - Gingin optical observations
  20. GRB 220706A: Prompt enhanced Swift-XRT position
  21. GRB 220706A: Swift detection of a burst
  22. GRB 220701A: Swift-BAT refined analysis
  23. GRB220408A: VIRT Optical Upper Limit
  24. GRB220412A: VIRT Optical Upper Limit
  25. GRB220701A: VIRT Optical Upper Limit
  26. GRB 220702B: Fermi GBM Final Localization
  27. GRB 220702A: Fermi GBM Final Localization
  28. GRB 220705A: Fermi GBM Final Localization
  29. Fermi trigger No 678635286: Global MASTER-Net observations report
  30. GRB 220701A: MITSuME Akeno optical upper limits
  31. Alert from the HAWC Burst Monitor HAWC-220702A
  32. GRB 220701A: COATLI Optical Upper Limit
  33. GRB 220701A: AbAO optical upper limit
  34. GRB 220627A: AstroSat CZTI detection
  35. GRB 220701A: Keck/LRIS Optical Upper Limit
  36. GRB 220701A: Swift-XRT refined Analysis
  37. GRB 220701A: LCO Optical Upper Limits
  38. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  39. GRB 220701A: BOOTES-5/JGT early optical upper limit
  40. GRB 220701A: Swift/UVOT Upper Limits
  41. GRB 220701A: Lowell Discovery Telescope Optical Observations
  42. GRB 220701A: Enhanced Swift-XRT position
  43. GRB 200701A: KAIT Optical Upper Limit
  44. GRB 220701A: Swift detection of a burst
  45. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  46. GRB 220627A, GROND observations
  47. GRB 220624A: AGILE/GRID refined analysis
  48. GRB 220627A: Swift/UVOT Upper Limits
  49. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  50. IceCube-220629A: No significant detection in HAWC
  51. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  52. IceCube-220627A: No significant detection in HAWC
  53. IceCube Alert 220629.99: Global MASTER-Net observations report
  54. GRB 220627A: Swift-XRT afterglow detection
  55. Konus-Wind detection of GRB 220627A
  56. Trigger 1113743: Swift detection of MAXI J0655-013
  57. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  58. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 220627A: VLT MUSE redshift
  60. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  61. GRB 220627A: MeerLICHT candidate optical afterglow
  62. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  63. GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
  64. Konus-Wind detection of GRB 220624A
  65. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  66. GRB 220627A: Swift ToO observations
  67. GRB 220627A: Fermi-LAT detection
  68. Fermi trigger No 678058621: Global MASTER-Net observations report
  69. GRB 220627A: MeerLICHT detection of two afterglow candidates
  70. Fermi GRB 220627A: Global MASTER-Net observations report
  71. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  72. GRB 220627A: Fermi GBM Final Real-time Localization
  73. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube Alert 220627.74: Global MASTER-Net observations report
  75. IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
  76. IceCube-220624A: No significant detection in HAWC
  77. GRB 220623A: GIT optical upper limits.
  78. GRB 220624A: CALET Gamma-Ray Burst Monitor detection
  79. GRB 220623A: T193-OHP optical upper limit
  80. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  81. GRB 220624A: Fermi GBM Detection
  82. Fermi GRB 220623B: Global MASTER-Net observations report
  83. Fermi GRB 220624A: Global MASTER-Net observations report
  84. IceCube Alert 220624.68: Global MASTER-Net observations report
  85. IPN triangulation of GRB 220624A
  86. GRB 220623A: Swift-BAT refined analysis
  87. GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
  88. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  89. GRB 220624A: AGILE/GRID analysis
  90. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  91. GRB 220624A: AGILE detection
  92. Konus-Wind detection of GRB 220623A
  93. GRB 220624B: Fermi GBM Final Real-time Localization
  94. GRB 220624A: Fermi GBM Final Real-time Localization
  95. GRB 220623A: AbAO optical upper limit
  96. GRB 220623A: Swift-XRT refined Analysis
  97. GRB 220623A: NOT optical observations
  98. GRB 220623A: Swift/UVOT Upper Limits
  99. GRB 220623A: BOOTES-5/JGT optical afterglow detection
  100. Konus-Wind detection of GRB 220609B

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