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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"

19547 results found.

  1. EP260809a: J-band upper limit with WINTER
  2. GRB 260808B: J-band upper limit with WINTER
  3. GRB 260808B: SVOM/ECLAIRs refined analysis
  4. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  5. GRB 260809A: SVOM detection of a faint burst
  6. GRB 260808B: Liverpool Telescope optical observations
  7. GRB 260808B: NOT optical observations
  8. GRB 260808B: LCO optical observations
  9. EP260809a: COLIBRÍ optical observations
  10. EP260809a: LCO optical observation
  11. EP260809a: OHP/T193 optical observations
  12. GRB260808B: OHP/T193 optical observations
  13. EP260809a: Einstein Probe detection of an X-ray transient
  14. GRB 260808B: SVOM/VT optical afterglow confirmation
  15. GRB 260808C: Fermi GBM Final Real-time Localization
  16. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  17. GRB 260808B: SVOM/VT optical candidate from VHF data
  18. GRB 260808B: SVOM detection of a faint burst
  19. GRB 260808A: Fermi GBM Final Real-time Localization
  20. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  21. GRB 260807A: SVOM possible detection of a faint burst
  22. EP260806a: COLIBRÍ optical observations
  23. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  24. EP260806a: SVOM/VT optical observation
  25. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  26. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  27. EP260806a: LCO likely optical counterpart
  28. EP260806a: Einstein Probe detection of an X-ray transient
  29. GRB 260802A: SVOM/VT optical upper limits from VHF data
  30. GRB 260802A: LCO optical upper limits
  31. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  32. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  33. GRB 260731A: AstroSat CZTI detection of a long burst
  34. EP260731a: COLIBRÍ optical upper limit
  35. EP260731a: NOT optical upper limit
  36. EP260731a: Einstein Probe detection of an X-ray transient
  37. EP260728a: COLIBRÍ optical upper limit
  38. EP260729a: Einstein Probe detection of an X-ray transient
  39. EP260727a: SAO RAS optical observations
  40. GRB 260727A: AbAO and SAO RAS optical observations
  41. EP260728a: Einstein Probe detection of a fast X-ray transient
  42. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  43. EP260727a: OHP/T193 optical observations
  44. GRB 260726A: Liverpool Telescope optical observations
  45. GRB 260727A: Liverpool Telescope optical upper limits
  46. EP260727a: Liverpool Telescope confirmation of optical counterpart
  47. EP260727a: Einstein Probe detection of an X-ray transient
  48. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  49. GRB 260726A: J-band upper limit with WINTER
  50. GRB 260727A: J-band upper limit with WINTER
  51. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  52. EP260723a: SVOM/ECLAIRs Upper Limit
  53. GRB 260727A: Kilonova-Catcher optical upper limit
  54. GRB 260727A: LCO optical upper limits
  55. GRB 260727A: SVOM detection of a bright long burst
  56. GRB 260726A: SVOM detection of a burst
  57. EP260725a: EP-WXT detection of an X-ray transient
  58. GRB 260616A: cubesat Avion detection
  59. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  60. GRB 260602B: cubesat Avion detection
  61. GRB 260601A: cubesat Avion detection
  62. EP260723a: SVOM/VT optical observation
  63. EP260723a: COLIBRÍ optical observations
  64. EP260723a: NOT optical conterpart confirmation
  65. EP260723a: Liverpool Telescope likely optical counterpart
  66. EP260723a: EP-WXT detection of a fast X-ray transient
  67. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  68. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  69. GRB 260718A: LCO optical upper limits
  70. GRB 260710A: SVOM/GRM observation
  71. GRB 260718A : GRANDMA and KNC upper limits
  72. GRB 260718A: SVOM/VT optical upper limits
  73. GRB 260718A: SVOM/VT optical upper limits from VHF data
  74. GRB 260714B: SVOM/GRM observation
  75. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  76. GRB 260714B: COLIBRÍ optical counterpart candidate
  77. sb26071506: SVOM detection of a X-ray transient
  78. EP260703a: SVOM/ECLAIRs Upper Limit
  79. GRB 260709A: AstroSat CZTI detection
  80. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  81. GRB 260706A: ATCA detection of possible radio counterpart
  82. GRB 260705A: ATCA radio observations
  83. EP260713a: Einstein Probe detection of an X-ray transient
  84. EP260623a: KAIT optical observations
  85. GRB 260708A: GRANDMA Optical Observations
  86. GRB 260708A: LCO optical observations
  87. EP260711a: Einstein Probe detection of an X-ray transient
  88. GRB 260709A: SVOM/GRM detection
  89. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  90. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  91. GRB 260706A : GRANDMA Upper limits
  92. GRB 260708A: Kilonova-Catcher optical afterglow detection
  93. IceCube-260708A: One candidate from the Zwicky Transient Facility
  94. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  95. GRB260708B: MAXI/GSC detection
  96. GRB 260705B: SVOM/GRM observation
  97. EP260707a (by EP-FXT): NOT optical upper limit
  98. EP260707a is not a real source
  99. EP260707a: LCOGT Optical Upper Limit
  100. EP260707a: TRT optical upper limit

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