Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. 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"

27036 results found.

  1. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  2. GRB 260802A / EP J223759.5+531421: SVOM/VT optical upper limit
  3. GRB 260802A: SVOM/VT optical upper limits from VHF data
  4. GRB 260802A: LCO optical upper limits
  5. GRB 260802B: Fermi GBM Final Localization
  6. The EP-WXT trigger 01709277420 is likely a flaring star
  7. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  8. GRB 260727A: EP-FXT further follow-up observations and candidate afterglow
  9. GRB 260618B: SVOM/VT continued optical observations indicated a steeper and redder decay
  10. GRB 260731A: AstroSat CZTI detection of a long burst
  11. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  12. GRB 260730B: AstroSat CZTI detection
  13. EP260731a: NOT optical upper limit
  14. GRB 260730B: NuSTAR detection of prompt emission
  15. EP260731a: Einstein Probe detection of an X-ray transient
  16. GRB 260727A: SVOM/ECLAIRs refined analysis
  17. GRB 260726A: SVOM/ECLAIRs refined analysis
  18. GRB260730A: Fermi GBM Final Localization
  19. EP260727a: VLT/X-shooter spectroscopic redshift z = 2.817
  20. The EP-WXT trigger 01709277130 (EP260729a): refined EP-WXT analysis and association with a flaring star
  21. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  22. EP260729a: Einstein Probe detection of an X-ray transient
  23. EP260727a: SAO RAS optical observations
  24. EP260728a: EP-FXT follow-up observation
  25. GRB 260726A: EP-FXT follow-up observations
  26. EP260728a: Einstein Probe detection of a fast X-ray transient
  27. GRB 260727A: SVOM/GRM observation
  28. GRB 260726A: Fermi GBM Observation
  29. EP260727a: 1.5m OSN optical counterpart detection
  30. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  31. EP260727a: OHP/T193 optical observations
  32. EP260727a: Liverpool Telescope confirmation of optical counterpart
  33. EP260727a: NUTTELA-TAO Early Optical Limits
  34. GRB 260728A: Fermi GBM Final Localization
  35. GRB 260727A: EP/FXT follow-up observations
  36. EP260727a: Einstein Probe detection of an X-ray transient
  37. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  38. GRB 260727A: Glowbug gamma-ray detection
  39. GRB 260726A: J-band upper limit with WINTER
  40. GRB 260727A: J-band upper limit with WINTER
  41. GRB 260726A: SVOM/VT optical candidate
  42. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  43. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  44. EP260723a: SVOM/ECLAIRs Upper Limit
  45. GRB 260727A: GOTO early optical upper limit
  46. GRB 260727A: AstroSat CZTI detection
  47. GRB 260727A: Kilonova-Catcher optical upper limit
  48. GRB 260727A: LCO optical upper limits
  49. GRB 260727B: Fermi GBM Final Real-time Localization
  50. GRB 260727A: SVOM detection of a bright long burst
  51. GRB 260726A: SVOM detection of a burst
  52. GRB 260726A: Fermi GBM Final Real-time Localization
  53. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  54. EP260723a: further EP-FXT follow-up observation
  55. EP260725a: EP-FXT follow-up observation and association with a bright flaring star
  56. EP260725a: EP-WXT detection of an X-ray transient
  57. GRB 260616A: cubesat Avion detection
  58. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  59. GRB 260602B: cubesat Avion detection
  60. GRB 260601A: cubesat Avion detection
  61. EP260723a: EP-FXT follow-up observation
  62. IPN triangulation of GRB 260706B
  63. GRB 260718A: SVOM/ECLAIRs refined analysis
  64. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  65. EP260723a: SVOM/VT optical observation
  66. EP260723a: NOT optical conterpart confirmation
  67. EP260723a: Liverpool Telescope likely optical counterpart
  68. EP260723a: EP-WXT detection of a fast X-ray transient
  69. GRB 260723A: Fermi GBM Final Localization
  70. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  71. GRB 260722A: Fermi GBM Final Real-time Localization
  72. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  73. Fermi GBM trigger 806384210/260722151 is not a GRB
  74. GRB 260721A: NuSTAR detection of prompt emission
  75. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  76. GRB 260705A: Retraction of optical counterpart
  77. GRB 260714B: Insight-HXMT/HE detection
  78. GRB 260718A: EP-FXT follow-up observation
  79. GRB 260718A: LCO optical upper limits
  80. GRB 260711A: SVOM/GRM observation
  81. GRB 260710A: SVOM/GRM observation
  82. GRB 260718A: Fermi GBM Observation
  83. GRB 260718A : GRANDMA and KNC upper limits
  84. GRB 260718A: SVOM/VT optical upper limits
  85. GRB 260718A: SVOM/VT optical upper limits from VHF data
  86. GRB 260718A: SVOM detection of a burst
  87. GRB 260714B: SVOM/GRM observation
  88. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  89. GRB 260714B: GECAM-B observation of a burst
  90. GRB 260618B: EP-FXT follow-up observation upper limit
  91. GRB 260714B: COLIBRÍ optical counterpart candidate
  92. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  93. sb26071506: SVOM detection of a X-ray transient
  94. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  95. GRB 260715A: Fermi GBM Final Real-time Localization
  96. EP260703a: SVOM/ECLAIRs Upper Limit
  97. GRB 260710A: AstroSat CZTI detection
  98. GRB 260709A: AstroSat CZTI detection
  99. GRB 260714B: AstroSat CZTI detection
  100. GRB 260714B: Fermi-LAT detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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