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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"

19539 results found.

  1. EP260809a: COLIBRÍ optical observations
  2. EP260809a: LCO optical observation
  3. EP260809a: OHP/T193 optical observations
  4. GRB260808B: OHP/T193 optical observations
  5. EP260809a: Einstein Probe detection of an X-ray transient
  6. GRB 260808B: SVOM/VT optical afterglow confirmation
  7. GRB 260808C: Fermi GBM Final Real-time Localization
  8. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  9. GRB 260808B: SVOM/VT optical candidate from VHF data
  10. GRB 260808B: SVOM detection of a faint burst
  11. GRB 260808A: Fermi GBM Final Real-time Localization
  12. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  13. GRB 260807A: SVOM possible detection of a faint burst
  14. EP260806a: COLIBRÍ optical observations
  15. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  16. EP260806a: SVOM/VT optical observation
  17. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  18. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  19. EP260806a: LCO likely optical counterpart
  20. EP260806a: Einstein Probe detection of an X-ray transient
  21. GRB 260802A: SVOM/VT optical upper limits from VHF data
  22. GRB 260802A: LCO optical upper limits
  23. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  24. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  25. GRB 260731A: AstroSat CZTI detection of a long burst
  26. EP260731a: COLIBRÍ optical upper limit
  27. EP260731a: NOT optical upper limit
  28. EP260731a: Einstein Probe detection of an X-ray transient
  29. EP260728a: COLIBRÍ optical upper limit
  30. EP260729a: Einstein Probe detection of an X-ray transient
  31. EP260727a: SAO RAS optical observations
  32. GRB 260727A: AbAO and SAO RAS optical observations
  33. EP260728a: Einstein Probe detection of a fast X-ray transient
  34. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  35. EP260727a: OHP/T193 optical observations
  36. GRB 260726A: Liverpool Telescope optical observations
  37. GRB 260727A: Liverpool Telescope optical upper limits
  38. EP260727a: Liverpool Telescope confirmation of optical counterpart
  39. EP260727a: Einstein Probe detection of an X-ray transient
  40. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  41. GRB 260726A: J-band upper limit with WINTER
  42. GRB 260727A: J-band upper limit with WINTER
  43. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  44. EP260723a: SVOM/ECLAIRs Upper Limit
  45. GRB 260727A: Kilonova-Catcher optical upper limit
  46. GRB 260727A: LCO optical upper limits
  47. GRB 260727A: SVOM detection of a bright long burst
  48. GRB 260726A: SVOM detection of a burst
  49. EP260725a: EP-WXT detection of an X-ray transient
  50. GRB 260616A: cubesat Avion detection
  51. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  52. GRB 260602B: cubesat Avion detection
  53. GRB 260601A: cubesat Avion detection
  54. EP260723a: SVOM/VT optical observation
  55. EP260723a: COLIBRÍ optical observations
  56. EP260723a: NOT optical conterpart confirmation
  57. EP260723a: Liverpool Telescope likely optical counterpart
  58. EP260723a: EP-WXT detection of a fast X-ray transient
  59. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  60. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  61. GRB 260718A: LCO optical upper limits
  62. GRB 260710A: SVOM/GRM observation
  63. GRB 260718A : GRANDMA and KNC upper limits
  64. GRB 260718A: SVOM/VT optical upper limits
  65. GRB 260718A: SVOM/VT optical upper limits from VHF data
  66. GRB 260714B: SVOM/GRM observation
  67. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  68. GRB 260714B: COLIBRÍ optical counterpart candidate
  69. sb26071506: SVOM detection of a X-ray transient
  70. EP260703a: SVOM/ECLAIRs Upper Limit
  71. GRB 260709A: AstroSat CZTI detection
  72. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  73. GRB 260706A: ATCA detection of possible radio counterpart
  74. GRB 260705A: ATCA radio observations
  75. EP260713a: Einstein Probe detection of an X-ray transient
  76. EP260623a: KAIT optical observations
  77. GRB 260708A: GRANDMA Optical Observations
  78. GRB 260708A: LCO optical observations
  79. EP260711a: Einstein Probe detection of an X-ray transient
  80. GRB 260709A: SVOM/GRM detection
  81. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  82. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  83. GRB 260706A : GRANDMA Upper limits
  84. GRB 260708A: Kilonova-Catcher optical afterglow detection
  85. IceCube-260708A: One candidate from the Zwicky Transient Facility
  86. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  87. GRB260708B: MAXI/GSC detection
  88. GRB 260705B: SVOM/GRM observation
  89. EP260707a (by EP-FXT): NOT optical upper limit
  90. EP260707a is not a real source
  91. EP260707a: LCOGT Optical Upper Limit
  92. EP260707a: TRT optical upper limit
  93. EP260707a: Einstein Probe detection of an X-ray transient
  94. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  95. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  96. GRB 260706A: SVOM/GRM observation
  97. GRB 260706A: REM optical/NIR observations
  98. GRB 260706A: LCO optical upper limit
  99. GRB 260706A: SVOM detection of a burst
  100. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare

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