Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

12171 results found.

  1. GRB 250211B: A long GRB detected by INTEGRAL
  2. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  3. GRB 250207A: Fermi GBM Observation
  4. Konus-Wind detection of GRB 250207A
  5. Konus-Wind detection of GRB 250206A
  6. EP250207b: Global MASTER-Net observations report
  7. GRB 250207A: Skynet optical afterglow observations
  8. GRB 250210A: AstroSat CZTI detection
  9. EP250207b: a new X-ray transient detected by Einstein Probe
  10. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  11. Fermi GRB 250210A: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  13. IceCube Alert 250207.09: Global MASTER-Net observations report
  14. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  15. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  16. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  17. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  18. GRB 250206A: Fermi-LAT detection
  19. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  20. GRB 250207A: Swift-XRT refined Analysis
  21. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  22. Konus-Wind detection of GRB 250204B
  23. GRB 250129A: Continued AbAO and Mondy optical observations
  24. GRB 250207B: MAXI/GSC detection
  25. The EP-WXT trigger 01709131332 is likely a flaring star
  26. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  27. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  28. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  30. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  31. EP250205a/GRB 250205A: Einstein Probe observation
  32. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  33. Konus-Wind detection of GRB 250201A
  34. Konus-Wind detection of GRB 250202B
  35. GRB 250204B: AstroSat CZTI detection of a short burst
  36. GRB 250202C: GRBAlpha detection
  37. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  38. GRB 250202C: Fermi GBM Final Real-time Localization
  39. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  40. Swift GRB250129A: MASTER 4 days observations report
  41. GRB 250201A: INTEGRAL SPI/ACS detection
  42. Konus-Wind detection of GRB 250129A
  43. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  44. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  45. GRB 250128B: VLA possible radio detection
  46. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  47. GRB 250129A: Skynet optical observations
  48. GRB 250129A: Swift-XRT refined Analysis
  49. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  50. GRB 250128B: VLT/FORS2 optical observations
  51. GRB 250128B: Swift-XRT refined Analysis
  52. Swift GRB 250128B: Global MASTER-Net observations report
  53. EP250125a: Upper limits from Swift/BAT-GUANO
  54. GRB 250128B: Swift detection of a short burst
  55. GRB 250127B: DDOTI Upper Limit on the Afterglow
  56. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  57. GRB 250127A: EP-FXT afterglow detection
  58. GRB 250117A: Fermi GBM Observation
  59. Fermi GRB 250127B: Global MASTER-Net observations report
  60. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  61. GRB 250126A: MAXI/GSC detection
  62. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  63. GECAM-A detection of a bright burst from SGR 1E1841-045
  64. EP250125a: a new X-ray transient detected by Einstein Probe
  65. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  66. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  67. IPN triangulation of a bright burst from SGR 1E1841-045
  68. EP250108a: AbAO, CMO and Terskol optical upper limits
  69. Konus-Wind detection of GRB 250118B
  70. GRB 250121A: Fermi GBM Observation
  71. IPN triangulation of GRB 250118B
  72. Konus-Wind detection of GRB 250119B
  73. IPN triangulation of GRB 250119B
  74. GRB 250121A: Fermi-LAT detection
  75. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  76. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  77. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  78. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  79. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  80. Konus-Wind detection of GRB 250117A
  81. IPN triangulation of GRB 250117A (short)
  82. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  83. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  84. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  85. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  86. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  87. GRB 250117A: GECAM observation of a short burst
  88. Konus-Wind detection of GRB 250116A
  89. GRB 250116A: GECAM-B detection of a long burst
  90. GRB 250116A: Fermi-LAT detection
  91. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  92. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  93. Konus-Wind detection of GRB 250113A
  94. IPN triangulation of GRB 250113A
  95. GRB 250114A: Swift-XRT refined Analysis
  96. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  97. GRB 250114A: Swift detection of a burst with an optical counterpart
  98. GRB 250101A: Terskol Zeiss-2000 optical observations
  99. GRB 250106A: Swift-XRT afterglow detection
  100. Fermi trigger No 758442826: Global MASTER-Net observations report

Advanced

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