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"
  1. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  2. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  3. IceCube Alert 230201.26: Global MASTER-Net observations report
  4. Fermi GRB 230201B: Global MASTER-Net observations report
  5. Fermi-LAT gamma-ray observations of IceCube-230201A
  6. GRB 230201B: Fermi GBM Final Real-time Localization
  7. GRB 230126A: Detection by VZLUSAT-2
  8. Fermi GRB 230201A: Global MASTER-Net observations report
  9. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  10. GRB 221009A: radio afterglow detection with the EVN
  11. GRB 230201A: Fermi GBM Final Real-time Localization
  12. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  13. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  14. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  15. AT2023avj: X-ray Detection with Swift/XRT
  16. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  17. GRB 230129A: AstroSat CZTI detection
  18. GRB 230128A: AstroSat CZTI detection
  19. GRB 230130A: Fermi GBM Final Real-time Localization
  20. ZTF23aaarlti/AT2023avj: VLA radio detection
  21. GRB 230129A: Fermi GBM Final Real-time Localization
  22. GRB 230128A: Fermi GBM Final Real-time Localization
  23. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  24. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  25. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  26. AT2023avj ZTF Candidate: Assy optical observations
  27. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  28. GRB 230126A: Fermi GBM Final Real-time Localization
  29. Swift-XRT observations of NuEm-230125A
  30. Trigger 1150965: Swift detection of LS V +44 17
  31. GRB 230124A: Fermi GBM Observation
  32. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230125A
  33. GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
  34. IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 230114B: Detection by VZLUSAT-2
  36. GRB 230123A: LCOGT Optical Upper Limits
  37. Fermi GRB 230124A: Global MASTER-Net observations report
  38. GRB 230124A: Fermi GBM Final Real-time Localization
  39. GRB 230123A: Swift-BAT refined analysis
  40. GRB 230122A: Swift/BAT-GUANO detection
  41. Fermi-LAT gamma-ray observations of IceCube-230122A
  42. GRB 230123A: Swift/UVOT Upper Limits
  43. GRB 230123A: Swift-XRT refined Analysis
  44. GRB 230123A: Enhanced Swift-XRT position
  45. GRB 230123A: Zadko observatory - Gingin optical observations
  46. GRB 230116C: Swift-XRT observations
  47. GRB 230123A: Swift detection of a burst
  48. IceCube Alert 230122.16: Global MASTER-Net observations report
  49. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 230116B: Fermi GBM observation
  51. Trigger 1150107: Swift detection of LS V +44 17
  52. GRB 230120A: AstroSat CZTI detection
  53. IPN triangulation of GRB 230116B (short)
  54. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 230116D: 3.6m DOT optical upper limit
  56. GRB 230119A: Fermi GBM Final Real-time Localization
  57. Fermi GRB 230118A: Global MASTER-Net observations report
  58. GRB 230118A: Fermi GBM Final Real-time Localization
  59. GRB 230116D: Swift-BAT refined analysis
  60. GRB 230116C: Swift-BAT refined analysis
  61. GRB 230116D: SAO RAS further observations
  62. GRB 230116D: SAO RAS photometry
  63. GRB 230116D: KGO RC-25 optical observations
  64. GRB 230116D: Sintez-Newton/CrAO optical observations
  65. GRB 230116D: LCOGT Optical Upper Limit
  66. GRB 230116D: SAO RAS redshift
  67. Fermi trigger No 695569700: Global MASTER-Net observations report
  68. GRB 230116D: Swift-XRT refined Analysis
  69. Fermi GRB 230117A: Global MASTER-Net observations report
  70. GRB 230117A: Fermi GBM Final Real-time Localization
  71. GRB 230116D: GIT optical follow-up
  72. GRB 230116D: GIT optical follow-up
  73. GRB 230116D: Enhanced Swift-XRT position
  74. GRB 230116D: SAO RAS observations of OT brightening
  75. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  76. GRB 230116D: Nanshan/NEXT optical afterglow detection
  77. GRB 230116D: Swift detection of a burst
  78. Swift GRB230116.88: Global MASTER-Net observations report
  79. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  80. GRB 230116C: Swift detection of a burst
  81. GRB 230116B: Fermi GBM Final Real-time Localization
  82. GRB 230116A: Fermi GBM Final Real-time Localization
  83. GRB 230114A: Detection by VZLUSAT-2
  84. Fermi-LAT gamma-ray observations of IceCube-230112A
  85. GRB 230114A: Fermi GBM Final Real-time Localization
  86. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-230109A
  87. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  88. IceCube-230112A: Upper limits from a search for additional neutrino events in IceCube
  89. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  90. Trigger 1148770: Swift detection of Cyg X-1 due to Star Tracker loss of lock
  91. GRB 230111A: Fermi GBM Observation
  92. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  93. Fermi GRB 230112A: Global MASTER-Net observations report
  94. IceCube Alert 230112.28: Global MASTER-Net observations report
  95. GRB 230112A: Fermi GBM Final Real-time Localization
  96. GRB 230111A: MAXI/GSC detection
  97. GRB 230111A: Fermi GBM Final Real-time Localization
  98. GRB 230106: AstroSat LAXPC detection
  99. IceCube-Cascade 230109A: Upper limits from a search for additional neutrino events in IceCube
  100. Fermi trigger No 695057654: Global MASTER-Net observations report

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