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"

32695 results found.

  1. GRB 251129B: Glowbug gamma-ray detection of a short burst
  2. GRB 251203A: AstroSat CZTI detection
  3. EP251130a: JinShan near-infrared observations
  4. GRB 251203C: LCO optical afterglow confirmation
  5. GRB 251203C: SVOM/VT optical counterpart
  6. GRB 251203C: EP-FXT follow-up observation
  7. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  8. GRB 251203B: Swift-XRT observations
  9. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  10. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  11. GRB 251203C: LCO optical upper limits
  12. GRB 251203B: LCO optical upper limits
  13. GRB 251203B: SVOM/VT optical observation
  14. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  15. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  16. GRB 251201B: Insight-HXMT/HE detection
  17. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  18. EP251130a: MAO/AZT-22 optical observations
  19. EP251202a / GRB251202A: AstroSat CZTI detection
  20. GRB 251202A / EP251202a: SVOM/VT optical observation
  21. GRB 251201B: Fermi GBM Observation
  22. EP251202a/GRB 251202A: KAIT optical observations
  23. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  24. Fermi GRB 251202B: Global MASTER-Net observations report
  25. IPN triangulation of GRB 251129B (short/hard)
  26. GRB251129A/EP251129a: Swift UVOT detection
  27. GRB 251202A: Fermi GBM Observation
  28. GRB 251202A: Swift/UVOT Detection
  29. GRB 251201B: Kilonova-Catcher optical afterglow detection
  30. GRB 251201B: Swift/UVOT Detection
  31. GRB 251130B: Glowbug gamma-ray detection
  32. GRB 251201B: GECAM-B observation of a long burst
  33. EP251130a: continued NOT optical observations indicate steep fading phase
  34. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  35. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  36. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  37. GRB 251202A: GOTO optical afterglow detection
  38. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  39. GRB 251201A: GECAM-B observation of a burst
  40. GRB 251126A: SAO RAS optical marginal detection
  41. GRB 251202A: Swift-XRT afterglow detection
  42. EP251129a/GRB 251129A: NOWT Detection
  43. GRB 251126A: SVOM/VT optical observation
  44. EP251130a: SVOM/VT optical observation
  45. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  46. Fermi GRB 251202A: Global MASTER-Net observations report
  47. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  48. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  49. GRB 251201A: SVOM/GRM observation of a burst
  50. GRB 251201B: SVOM/VT optical fading
  51. Swift GRB 251201B : MASTER optical counterpart detection
  52. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  53. Swift GRB 251201B: Global MASTER-Net observations report
  54. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  55. GRB 251130B: AstroSat CZTI detection
  56. EP251130a: Mondy optical observations
  57. EP251130a: Optical detections with Kinder observations
  58. EP251130a: SAO RAS optical observations
  59. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  60. EP251130a: KAIT optical observations
  61. EP251130A: Optical observation from 1.3m DFOT
  62. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  63. EP251130a: JinShan optical observations
  64. Fermi GRB 251130B: Global MASTER-Net observations report
  65. GRB 251127A: SVOM/GRM observation
  66. EP251130a: Swift-XRT counterpart detection
  67. EP251130a: Global MASTER-Net observations report
  68. EP251130a: COLIBRÍ optical counterpart candidate
  69. EP251129a/GRB 251129A: EP-FXT follow-up observations
  70. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  71. GRB 251128A: AstroSat CZTI detection
  72. GRB 251129A / EP251129a: SAO RAS optical observations
  73. GRB 251126A: SAO RAS optical observations
  74. GRB 251128A: GECAM-B detection
  75. GRB 251128A: SVOM/GRM observation of a long burst
  76. GRB 251128A: Insight-HXMT/HE detection
  77. SVOM GRB 251129A : MASTER optical counterpart detection
  78. GRB 251129A: Swift-XRT afterglow detection
  79. GRB 251129A: Swift ToO observations
  80. GRB 251129A / EP251129a: SVOM/VT optical fading
  81. EP251129a: Global MASTER-Net observations report
  82. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  83. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  84. GRB 251129A: Correction to the position of the optical counterpar
  85. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  86. GRB 251128A: Fermi GBM Observation
  87. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  88. GRB 251126A: Swift-BAT refined analysis
  89. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  90. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  91. Fermi GRB 251128A: Global MASTER-Net observations report
  92. GRB 251127A: Glowbug gamma-ray detection
  93. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  94. GRB 251126A: further SAO RAS optical observations
  95. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  96. GRB 251126A NUTTelA-TAO Early Measurements
  97. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  98. GRB251126A: MAO/AZT-22 optical observations
  99. GRB251126A: Continued optical observation from 1.3m DFOT
  100. GRB 251126A: Swift/UVOT Detection

Advanced

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