Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

10764 results found.

  1. GRB 231215A: radio detection with the VLA
  2. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  3. GRB 240107A: MAXI/GSC detection
  4. GRB 240106B: Fermi GBM Final Real-time Localization
  5. Fermi trigger No 726194053: Global MASTER-Net observations report
  6. IceCube Alert 240105.52: Global MASTER-Net observations report
  7. GRB 240102A: 1.3m DFOT optical upper limit
  8. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  9. GRB 240102C: AstroSat CZTI detection
  10. GRB 240101C: AstroSat CZTI detection
  11. GRB 231230A: Swift-BAT refined analysis
  12. GRB 240101A: Swift-BAT refined analysis
  13. GRB 240102A: Swift-XRT refined Analysis
  14. GRB 240101A: Swift-XRT refined Analysis
  15. GRB 240101B: Swift detection of a burst
  16. GRB 240101A: Swift detection of a burst
  17. Fermi trigger No 725806648: Global MASTER-Net observations report
  18. GRB 231230A: Swift-XRT refined Analysis
  19. Fermi trigger No 725592555: Global MASTER-Net observations report
  20. GRB 231230A: Prompt enhanced Swift-XRT position
  21. GRB 231230A: Swift detection of a burst
  22. Swift GRB231230.06: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  24. IPN triangulation of GRB 231224A (short)
  25. Fermi trigger No 725143760: Global MASTER-Net observations report
  26. GRB 231224A: Fermi GBM Final Real-time Localization
  27. LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
  28. GRB 231222B: Swift-XRT afterglow detection
  29. Fermi trigger No 724921799: Global MASTER-Net observations report
  30. GRB 231222B: Fermi-LAT detection
  31. IceCube-231211A: GRANDMA observations of PKS2047+098
  32. Fermi trigger No 724781422: Global MASTER-Net observations report
  33. GRB 231220A: Fermi GBM Final Real-time Localization
  34. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  35. Fermi trigger No 724698747: Global MASTER-Net observations report
  36. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  37. GRB 231216A: 10.4 m GTC optical upper limit
  38. GRB 231216A: Nanshan/HMT optical upper limit
  39. GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
  40. GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
  41. GRB 231216A: Swift-XRT refined Analysis
  42. GRB 231215A: Swift-BAT refined analysis
  43. GRB 231216A: Swift detection of a burst
  44. Konus-Wind detection of GRB 231215A
  45. GRB 231215A: NOT optical observations
  46. GRB 231204A: VZLUSAT-2 detection
  47. GRB 231215A: AKO Optical Upper Limit
  48. GRB 231214A: Fermi GBM observation
  49. Konus-Wind detection of GRB 231210B
  50. GRB 231215A: AstroSat CZTI detection
  51. GRB 231214A: Swift-XRT refined Analysis
  52. GRB 231214A: AstroSat CZTI detection
  53. Swift GRB231215.41: Global MASTER-Net observations report
  54. GRB 231214A: Fermi-LAT detection
  55. GRB 231214B: Swift/BAT-GUANO detection of a burst
  56. GRB231214A: BOOTES-6/DPRT optical upper limit
  57. Fermi trigger No 724278269: Global MASTER-Net observations report
  58. Fermi trigger No 724233240: Global MASTER-Net observations report
  59. Swift GRB231214.85: Global MASTER-Net observations report
  60. GRB 231214A: Swift detection of a burst
  61. GRB 231214A: Fermi GBM Final Real-time Localization
  62. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  63. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  64. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  65. GRB 231212A: GECAM-C detection of a likely short burst
  66. Fermi trigger No 724035412: Global MASTER-Net observations report
  67. GRB 231210B: MeerLICHT afterglow observations
  68. GRB 231210B: Swift-BAT refined analysis
  69. GRB 231210B: Swift-XRT refined Analysis
  70. Fermi trigger No 723906955: Global MASTER-Net observations report
  71. GRB 231208A: AstroSat CZTI detection of a faint burst
  72. Fermi trigger No 723581802: Global MASTER-Net observations report
  73. GRB 231205B: Ondrejov D50 optical upper limit
  74. Fermi-LAT gamma-ray observations of IceCube-231202A
  75. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  76. GRB 231206A: GECAM-B detection of a short burst (correction)
  77. GRB 231206A: GECAM-B detection of a short burst
  78. GRB 231205B: Nanshan/HMT optical upper limit
  79. GRB 231205B: GECAM-B detection of a long burst
  80. GRB 231204A: Glowbug gamma-ray detection
  81. GRB 231204A: CALET Gamma-Ray Burst Monitor detection
  82. Fermi-LAT daily aperture light curve of T CrB now available
  83. GRB 231204A: AstroSat CZTI detection
  84. GRB 231205A: GECAM-B detection of a short burst
  85. Fermi trigger No 723435916: Global MASTER-Net observations report
  86. Fermi trigger No 723326169: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  88. Fermi trigger No 723412808: Global MASTER-Net observations report
  89. GRB 231204A: Fermi GBM Final Real-time Localization
  90. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  91. Konus-Wind detection of GRB 231129C
  92. Fermi trigger No 723149952: Global MASTER-Net observations report
  93. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  94. GRB 231129C: Fermi-LAT detection
  95. GRB 231129C: GECAM-B detection of a bright burst
  96. GRB 231129C: AstroSat CZTI detection
  97. GRB 231127A: GRBAlpha detection
  98. GRB 231129C: MAXI/GSC detection
  99. Fermi trigger No 722977823: Global MASTER-Net observations report
  100. GRB 231129B: MAXI/GSC detection

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