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"

23409 results found.

  1. EP260812a: Einstein Probe detection of an X-ray transient
  2. GRB 260809A: SAO RAS optical observations
  3. GRB 260808B: SAO RAS optical observations
  4. GRB 260808B: SVOM/VT optical re-brightening at day 3
  5. EP260806a: MAO/AZT-22 optical observations
  6. GRB260808B: MAO/AZT-22 optical observations
  7. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  8. GRB 260809A: J-band upper limit with WINTER
  9. GRB 260806A: Glowbug gamma-ray detection
  10. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  11. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  12. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  13. GRB 260809A: NOT optical observations
  14. GRB260809A: MAO/AZT-22 optical observations
  15. GRB260809A: OHP/T193 optical observations
  16. EP260809a: J-band upper limit with WINTER
  17. GRB 260808B: J-band upper limit with WINTER
  18. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  19. GRB 260809A: SVOM detection of a faint burst
  20. GRB 260808B: Liverpool Telescope optical observations
  21. GRB 260808B: NOT optical observations
  22. GRB 260808B: LCO optical observations
  23. EP260809a: COLIBRÍ optical observations
  24. EP260809a: LCO optical observation
  25. EP260809a: OHP/T193 optical observations
  26. GRB260808B: OHP/T193 optical observations
  27. EP260809a: Einstein Probe detection of an X-ray transient
  28. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  29. GRB 260808B: SVOM/VT optical candidate from VHF data
  30. GRB 260808B: SVOM detection of a faint burst
  31. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  32. EP260806a: COLIBRÍ optical observations
  33. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  34. EP260806a: SVOM/VT optical observation
  35. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  36. EP260806a: OSIRIS+/GTC redshift z=0.089
  37. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  38. EP260806a: LCO likely optical counterpart
  39. EP260806a: Einstein Probe detection of an X-ray transient
  40. GRB 260715A: cubesat Avion detection
  41. GRB 260709A: cubesat Avion detection
  42. GRB 260708A: cubesat Avion detection
  43. GRB 260730B: Glowbug gamma-ray detection
  44. GRB 260805C: Glowbug gamma-ray detection
  45. GRB 260805B: Glowbug gamma-ray detection
  46. GRB 260804A: Glowbug gamma-ray detection
  47. GRB 260803A: Fermi GBM Final Real-time Localization
  48. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  49. GRB 260802A: SVOM/VT optical upper limits from VHF data
  50. GRB 260802A: LCO optical upper limits
  51. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  52. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  53. GRB 260731A: AstroSat CZTI detection of a long burst
  54. GRB 260730B: AstroSat CZTI detection
  55. EP260731a: COLIBRÍ optical upper limit
  56. EP260731a: NOT optical upper limit
  57. EP260731a: Einstein Probe detection of an X-ray transient
  58. GRB 260727A: SVOM/ECLAIRs refined analysis
  59. EP260728a: COLIBRÍ optical upper limit
  60. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  61. EP260729a: Einstein Probe detection of an X-ray transient
  62. EP260727a: SAO RAS optical observations
  63. GRB 260727A: AbAO and SAO RAS optical observations
  64. EP260728a: Einstein Probe detection of a fast X-ray transient
  65. GRB 260727A: SVOM/GRM observation
  66. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  67. EP260727a: OHP/T193 optical observations
  68. Konus-Wind detection of GRB 260727A
  69. GRB 260726A: Liverpool Telescope optical observations
  70. GRB 260727A: Liverpool Telescope optical upper limits
  71. EP260727a: Liverpool Telescope confirmation of optical counterpart
  72. EP260727a: Einstein Probe detection of an X-ray transient
  73. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  74. GRB 260727A: Glowbug gamma-ray detection
  75. GRB 260726A: J-band upper limit with WINTER
  76. GRB 260727A: J-band upper limit with WINTER
  77. GRB 260726A: SVOM/VT optical candidate
  78. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  79. EP260723a: SVOM/ECLAIRs Upper Limit
  80. GRB 260727A: AstroSat CZTI detection
  81. GRB 260727A: Kilonova-Catcher optical upper limit
  82. GRB 260727A: LCO optical upper limits
  83. GRB 260726A: SVOM detection of a burst
  84. EP260725a: EP-WXT detection of an X-ray transient
  85. GRB 260616A: cubesat Avion detection
  86. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  87. GRB 260602B: cubesat Avion detection
  88. GRB 260601A: cubesat Avion detection
  89. IPN triangulation of GRB 260706B
  90. EP260723a: SVOM/VT optical observation
  91. EP260723a: COLIBRÍ optical observations
  92. EP260723a: NOT optical conterpart confirmation
  93. EP260723a: Liverpool Telescope likely optical counterpart
  94. EP260723a: EP-WXT detection of a fast X-ray transient
  95. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  96. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  97. GRB 260718A: LCO optical upper limits
  98. GRB 260710A: SVOM/GRM observation
  99. GRB 260718A: Fermi GBM Observation
  100. GRB 260718A : GRANDMA and KNC upper limits

Advanced

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