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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"

19545 results found.

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

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