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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28230 results found.

  1. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  2. EP260618a: EP-WXT detection of an X-ray transient
  3. GRB 260610B: AbAO optical observations
  4. GRB 260506B: cubesat Avion detection
  5. GRB 260617A: Fermi GBM Detection
  6. GRB 260616A: Fermi GBM Observation
  7. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  8. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  9. GRB 260429A: cubesat Avion detection
  10. GRB260616C: MAXI/GSC detection
  11. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  12. EP260616a: EP-WXT detection of a fast X-ray transient
  13. GRB 260616B: Fermi GBM Detection
  14. GRB 260616B: BALROG localization (Fermi Trigger 803286321 / GRB 260616295)
  15. GRB 260616A: BALROG localization (Fermi Trigger 803272919 / GRB 260616140)
  16. GRB 260610B: Terskol optical observations
  17. GRB 260610B: SVOM/GRM observation
  18. GRB 260614B: Fermi GBM Observation
  19. GRB 260614B: SVOM/VT optical candidate from VHF data
  20. GRB 260614B: SVOM detection of a burst
  21. GRB 260611B: SVOM/GRM detection
  22. The EP-WXT trigger 01709269488 is likely a flaring star
  23. GRB 260610B: further Liverpool Telescope optical observations
  24. GRB 260610B: Fermi GBM Observation
  25. GRB 260610B / AT2026owq: GRANDMA optical observations
  26. GRB 260610B / AT2026owq: further SAO RAS optical observations
  27. EP260605a: COLIBRÍ optical upper limits
  28. GRB 260610b: Liverpool Telescope optical observations
  29. EP260610b: Liverpool Telescope optical upper limits
  30. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  31. GRB 260610B / AT2026owq: SAO RAS optical observations
  32. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  33. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  34. GRB 260610B / AT2026owq: Early ATLAS observations
  35. GRB 260610B: TRT optical observation
  36. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  37. EP260610b: COLIBRÍ optical observations
  38. GRB 260610B: DDOTI optical observations
  39. EP260610b: MAO/AZT-22 optical observations
  40. EP260610b: NOT optical observation
  41. EP260610b: SVOM/VT optical confirmation with blue color
  42. GRB 260515A: SOAR optical observations
  43. EP260610a: SVOM/VT optical upper limits
  44. EP260610b: Einstein Probe detection of an X-ray transient
  45. EP260610a: COLIBRÍ optical upper limits
  46. EP260610a: Einstein Probe detection of a fast X-ray transient
  47. GRB 260608A: Fermi GRB Observation
  48. GRB 260604C: further SAO RAS optical observations
  49. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  50. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  51. GRB 260604C: SVOM/C-GFT upper limit
  52. EP260605a: EP-FXT follow-up observation
  53. GRB 260607A: TRT optical observations
  54. GRB 260604A: SVOM/GRM detection
  55. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  56. GRB 260607B: Fermi GBM Observation
  57. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  58. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  59. GRB 260604C: 6 GHz VLA observations
  60. GRB 260604C: SAO RAS optical observations
  61. GRB 260604B: SVOM/GRM detection
  62. EP260605a: Einstein Probe detection of a fast X-ray transient
  63. EP260603a: COLIBRÍ optical upper limit
  64. GRB 260604A: Glowbug gamma-ray detection
  65. GRB 260604C: LCO optical upper limit
  66. EP260602d: EP-FXT follow-up observation
  67. EP260602c: EP-FXT follow-up observation
  68. GRB 260601B / EP260601a: AstroSat CZTI detection
  69. GRB 260527A/EP260527a: 6 GHz VLA observations
  70. GRB 260604C: Kilonova-Catcher optical afterglow detection
  71. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  72. GRB 260604C: Jinshan optical observations
  73. GRB 260604C: Fermi GBM Observation
  74. EP260602d: J-band upper limit with WINTER
  75. EP260602b: J-band upper limit with WINTER
  76. GRB 260604C: LAST detection of optical counterpart candidate
  77. Fermi GRB 260604C: Global MASTER-Net observations report
  78. Fermi GRB 260604C: Global MASTER-Net observations report
  79. SVOM GRB260604.85: Global MASTER-Net observations report
  80. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  81. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  82. EP260602a: EP-FXT follow-up observation
  83. EP260603a: Global MASTER-Net observations report
  84. EP260603a: Einstein Probe detection of a fast X-ray transient
  85. EP260602d: Optical Upper limits with kinder observations
  86. EP260602b: Liverpool Telescope observations
  87. EP260602a: Liverpool Telescope optical upper limits
  88. EP260602b: Liverpool Telescope and LCO observations
  89. EP260602a: GTC and Liverpool Telescope optical observations
  90. EP260601a/GRB 260601B: EP-FXT follow-up observation
  91. GRB 260601B / EP260601a: Mondy optical upper limit
  92. EP260602b: EP-FXT follow-up observation
  93. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  94. GRB 260603A: Kilonova-Catcher optical upper limit
  95. GRB 260603A: SVOM/VT optical observations
  96. EP260602a: NOT NIR J-band observations
  97. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  98. EP260602d: Einstein Probe detection of a fast X-ray transient
  99. Fermi trigger No 802141998: Global MASTER-Net observations report
  100. GRB 260601A: SVOM/GRM observation of a short burst

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