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"

15280 results found.

  1. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  2. GRB 251023C: AstroSat CZTI detection
  3. EP251023b/GRB 251023B: JinShan optical observation
  4. GRB 251022A: Swift-XRT detection of GOTO25iym
  5. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  6. EP251023a: GROWTH-India Telescope optical observations
  7. GRB 251022A: Fermi GBM Observation
  8. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  9. GRB 251023B: Glowbug gamma-ray detection
  10. EP251023a: COLIBRÍ optical observations
  11. GRB 251022A: COLIBRÍ optical observations
  12. GRB 251022A: DDOTI Optical Detection
  13. EP251023a: GSP Optical Counterpart Detection
  14. EP251023a: Einstein Probe detection of an X-ray transient
  15. GRB 251022A: Fermi-LAT detection
  16. GRB 251016B: Fermi GBM Detection
  17. GRB 251022A: Tiled Swift observations
  18. GRB 251016A: SVOM/ECLAIRs refined analysis
  19. Fermi-LAT gamma-ray observations of IceCube-251018A
  20. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-251018A: DDOTI Optical Upper Limit
  22. GRB 251016A: Fermi GBM Observation
  23. GRB 251018A: Fermi GBM Observation
  24. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  25. GRB 251016A: HXMT/HE detection
  26. GRB 251016A: Swift/UVOT Detection
  27. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  28. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  29. GRB 251017A: SVOM/VT optical observation
  30. GRB 251011A: Fermi GBM Observation
  31. GRB 251013C: Liverpool Telescope observations
  32. GRB 251013C: Leavitt Observatory optical photometry
  33. GRB 251017A: JinShan observations of the optical afterglow
  34. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  35. GRB 251016A: AstroSat CZTI detection of a short burst
  36. GRB 251017A: COLIBRÍ Early Afterglow Detection
  37. GRB 251016B: AstroSat CZTI detection
  38. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  39. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  40. GRB 251016A: SVOM detection of a short burst
  41. GRB 251014B: PRIME J-band upper limit
  42. Upper limits from a search for additional neutrino events in IceCube
  43. GRB 251013C: Kilonova-Catcher optical afterglow detection
  44. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  45. Konus-Wind detection of GRB 251007A
  46. GRB 251013C: SVOM/ECLAIRs refined analysis
  47. GRB 251014B: VLT/FORS2 Optical Observation
  48. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) further multi-band optical observations
  49. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  51. GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  52. GRB 251013C: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an bright optical counterpart
  53. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  54. GRB 251014B: Swift ToO observations
  55. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  56. GRB 251013C: Bassano Bresciano Observatory optical observations
  57. GRB 251013C: Early and late-time optical counterpart detection by LCO
  58. GRB 251013D: Swift ToO observations
  59. GRB 251014A: DDOTI Upper Limit
  60. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  61. GRB 251013C: EP-FXT counterpart detection
  62. GRB 251013C: AstroSat CZTI detection
  63. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  64. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  65. GRB 251013C: Swift-XRT counterpart detection
  66. GRB 251013C: LAST detection of optical counterpart
  67. GRB 251013C: BOOTES-6 early optical detection
  68. GRB 251013C: SVOM/VT optical observation
  69. GRB 251013C: SVOM detection of a burst
  70. GRB 251013B: SVOM/GRM observation
  71. GRB 251013A: SVOM/GRM observation
  72. GRB 251003A: Mondy optical upper limit
  73. MASTER OT J011025.98-583210.6 : SVOM/VT optical observation
  74. GRB 251011A: Insight-HXMT detection
  75. GRB 251011B: SVOM/GRM observation
  76. GRB 251010A: AstroSat CZTI detection
  77. GRB 251011A: AstroSat CZTI detection
  78. GRB 251009B: SVOM/GRM observation of short GRB
  79. GRB251007A: Swift/UVOT Detection
  80. GRB 251009A: GECAM-B detection of a short burst
  81. GRB 251009A: Insight-HXMT detection of a short burst
  82. GRB 251009B: Insight-HXMT detection of a short burst
  83. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  84. GRB 251007A: SVOM/GRM observation
  85. GRB 251007A: Insight-HXMT detection
  86. GRB 251007B - SVOM/ECLAIRs refined analysis
  87. SVOM/sb25101004: SVOM detection of a stellar flare
  88. GRB 250916A: TERI Gamma-ray detection
  89. GRB 250919A: TERI gamma-ray detection
  90. GRB 251002A - SVOM/ECLAIRs refined analysis
  91. GRB 251007B: COLIBRÍ optical upper limit
  92. GRB 251007A: AstroSat CZTI detection
  93. GRB 251007A: AKO Optical Upper Limit
  94. GRB 251006B: Insight-HXMT detection
  95. GRB 251007A: SVOM/C-GFT optical observations
  96. GRB 251005C: PRIME J-band upper limit
  97. GRB 251007B: SVOM detection of a faint burst
  98. GRB 250702B/EP250702a: JWST/NIRCam Observations
  99. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  100. GRB 251006B: SVOM/GRM observation

Advanced

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