Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

1006 results found.

  1. GRB 250311A: Swift-XRT observations
  2. GRB 250311A/EP250311a: TRT optical upper limit
  3. GRB 250311A: Tiled Swift observations
  4. EP250311a/GRB 250311A: EP-WXT detection
  5. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  6. Fermi GRB 250226A: Global MASTER-Net observations report
  7. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  8. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  9. GRB 250207B: Swift-XRT observations
  10. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  11. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  12. GRB 250207B: Tiled Swift observations
  13. GRB 250207B: MAXI/GSC detection
  14. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  15. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  16. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  17. GRB 250126A: MAXI/GSC detection
  18. GRB 250101A: Swift detection of a burst with an optical counterpart
  19. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  20. GRB241229B: UVOT upper limits
  21. GRB 241213B: Swift-XRT observations
  22. GRB 241213B: Tiled Swift observations
  23. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  24. GRB 241213B: MAXI/GSC detection
  25. GRB 241207C: MASTER optical observations
  26. GRB 241207C: Tiled Swift observations
  27. GRB 241207C: MAXI/GSC detection
  28. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  30. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  31. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  32. Fermi trigger No 751563375: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  34. EP240913A / GRB 240913C: AstroSat CZTI detection
  35. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  36. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  37. GRB 240824B: Ondrejov D50 optical limit
  38. GRB 240824B: Fermi GBM Observation
  39. GRB 240824B: Swift-XRT afterglow detection
  40. GRB 240824B: Swift/BAT arcminute localization of a burst
  41. GRB 240824B: MAXI/GSC detection
  42. GRB 240809B: MAXI/GSC detection
  43. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  44. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  45. GRB 240523A: Swift-XRT refined Analysis
  46. GRB 240514E: A possible candidate BD-21 1074
  47. MAXI GRB240514.78: Global MASTER-Net observations report
  48. GRB 240514E: MAXI/GSC detection of a probable afterglow
  49. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  50. Fermi trigger No 737173236: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  52. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  53. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  54. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  55. GRB 240309A: MAXI/GSC detection
  56. GRB 240225B: Swift-XRT afterglow detection
  57. GRB 240225B: Glowbug gamma-ray detection
  58. GRB 240225B: Swift ToO observations
  59. Konus-Wind detection of GRB 240225B (long)
  60. GRB 240225B: VLT/X-shooter redshift
  61. GRB 240225B : MITSuME Akeno optical afterglow candidate detection
  62. GRB 240225B: 3.6m DOT observation
  63. GRB 240225B: NOT optical observations
  64. GRB 240225B: Nanshan/HMT optical afterglow detection
  65. GRB 240225B: CALET Gamma-Ray Burst Monitor detection
  66. GRB 240225B: Swift-XRT observations
  67. GRB 240225B: GOTO detection of a candidate optical afterglow
  68. GRB 240225B: AstroSat CZTI detection
  69. GRB 240225B: Tiled Swift observations
  70. GRB 240225B: MAXI/GSC detection
  71. VLA X-band observation of EPW20240219aa
  72. GRB 240128A: Further Swift-XRT observations
  73. GRB 240214A: Tiled Swift observations
  74. GRB 240214A/1H 0451-560: MAXI/GSC detection
  75. IPN triangulation of GRB 240125A (short)
  76. GRB 240128A: Glowbug gamma-ray detection
  77. GRB 240128A: Swift-XRT observations
  78. GRB 240128A: GRBAlpha detection
  79. GRB 240128A: Tiled Swift observations
  80. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  81. GRB 240128A: MAXI/GSC detection
  82. GRB 240122A: ATCA detection of radio counterpart
  83. GRB240122A: PRIME near infrared detection
  84. GRB 240122A: Swift/UVOT Upper Limits
  85. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  86. GRB 240122A: Swift-XRT afterglow detection
  87. GRB 240122A: VLT/X-shooter redshift confirmation
  88. GRB 240122A: Redshift from OSIRIS+/GTC
  89. GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
  90. GRB 240122A: GOTO optical counterpart candidate
  91. GRB 240122A: Tiled Swift observations
  92. GRB 240122A: MAXI/GSC detection
  93. GRID detection of GRB 231230A
  94. GRB 240107A: VZLUSAT-2 detection
  95. GRB 240114A: MAXI/GSC detection
  96. GRB 240107A: AstroSat CZTI detection
  97. GRB 240107A: MAXI/GSC detection
  98. IPN triangulation of GRB 231129C
  99. GRB 231129C: ASIM MXGS observation and localization
  100. Konus-Wind detection of GRB 231129C

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov