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"

26338 results found.

  1. GRB 260802A / EP J223759.5+531421: SVOM/VT optical upper limit
  2. GRB 260802A: SVOM/VT optical upper limits from VHF data
  3. GRB 260802A: LCO optical upper limits
  4. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  5. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  6. GRB 260727A: EP-FXT further follow-up observations and candidate afterglow
  7. GRB 260618B: SVOM/VT continued optical observations indicated a steeper and redder decay
  8. GRB 260731A: AstroSat CZTI detection of a long burst
  9. GRB 260730B: AstroSat CZTI detection
  10. EP260731a: COLIBRÍ optical upper limit
  11. EP260731a: NOT optical upper limit
  12. GRB 260730B: NuSTAR detection of prompt emission
  13. EP260731a: Einstein Probe detection of an X-ray transient
  14. GRB 260727A: SVOM/ECLAIRs refined analysis
  15. GRB 260726A: SVOM/ECLAIRs refined analysis
  16. EP260728a: COLIBRÍ optical upper limit
  17. EP260727a: VLT/X-shooter spectroscopic redshift z = 2.817
  18. The EP-WXT trigger 01709277130 (EP260729a): refined EP-WXT analysis and association with a flaring star
  19. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  20. EP260729a: Einstein Probe detection of an X-ray transient
  21. EP260727a: SAO RAS optical observations
  22. GRB 260727A: AbAO and SAO RAS optical observations
  23. EP260728a: EP-FXT follow-up observation
  24. GRB 260726A: EP-FXT follow-up observations
  25. EP260728a: Einstein Probe detection of a fast X-ray transient
  26. GRB 260727A: SVOM/GRM observation
  27. GRB 260726A: Fermi GBM Observation
  28. EP260727a: 1.5m OSN optical counterpart detection
  29. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  30. Konus-Wind detection of GRB 260727A
  31. GRB 260726A: Liverpool Telescope optical observations
  32. GRB 260727A: Liverpool Telescope optical upper limits
  33. EP260727a: Liverpool Telescope confirmation of optical counterpart
  34. EP260727a: NUTTELA-TAO Early Optical Limits
  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 260727A: SVOM detection of a bright long burst
  50. GRB 260726A: SVOM detection of a burst
  51. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  52. EP260723a: further EP-FXT follow-up observation
  53. EP260725a: EP-FXT follow-up observation and association with a bright flaring star
  54. EP260725a: EP-WXT detection of an X-ray transient
  55. GRB 260616A: cubesat Avion detection
  56. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  57. GRB 260602B: cubesat Avion detection
  58. GRB 260601A: cubesat Avion detection
  59. EP260723a: EP-FXT follow-up observation
  60. IPN triangulation of GRB 260706B
  61. GRB 260718A: SVOM/ECLAIRs refined analysis
  62. EP260723a: SVOM/VT optical observation
  63. EP260723a: COLIBRÍ optical observations
  64. EP260723a: NOT optical conterpart confirmation
  65. EP260723a: EP-WXT detection of a fast X-ray transient
  66. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  67. Konus-Wind detection of GRB 260721A
  68. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  69. GRB 260721A: NuSTAR detection of prompt emission
  70. Konus-Wind detection of GRB 260714B
  71. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  72. GRB 260705A: Retraction of optical counterpart
  73. GRB 260714B: Insight-HXMT/HE detection
  74. GRB 260718A: EP-FXT follow-up observation
  75. GRB 260718A: LCO optical upper limits
  76. GRB 260711A: SVOM/GRM observation
  77. GRB 260710A: SVOM/GRM observation
  78. GRB 260718A: Fermi GBM Observation
  79. GRB 260718A : GRANDMA and KNC upper limits
  80. GRB 260718A: SVOM/VT optical upper limits
  81. GRB 260718A: SVOM/VT optical upper limits from VHF data
  82. GRB 260718A: SVOM detection of a burst
  83. GRB 260714B: SVOM/GRM observation
  84. GRB 260714B: GECAM-B observation of a burst
  85. GRB 260618B: EP-FXT follow-up observation upper limit
  86. GRB 260714B: COLIBRÍ optical counterpart candidate
  87. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  88. SVOM sb26071506: Global MASTER-Net observations report
  89. sb26071506: SVOM detection of a X-ray transient
  90. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  91. EP260703a: SVOM/ECLAIRs Upper Limit
  92. GRB 260710A: AstroSat CZTI detection
  93. GRB 260709A: AstroSat CZTI detection
  94. GRB 260714B: AstroSat CZTI detection
  95. GRB 260714B: Fermi-LAT detection
  96. GRB 260714B: Fermi GBM Detection
  97. GRB 260706A: ATCA detection of possible radio counterpart
  98. GRB 260705A: ATCA radio observations
  99. EP260713a: Einstein Probe detection of an X-ray transient
  100. GRB 260619A: SVOM/VT continuous optical observations

Advanced

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