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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"

26733 results found.

  1. The EP-WXT trigger 01709322206 is likely a flaring star
  2. GRB 261102A: Fermi GBM Detection
  3. GRB 261102A: Fermi GBM Final Real-time Localization
  4. GRB 261101B: BALROG localization (Fermi Trigger 815240277 / GRB 261101651)
  5. EP261030a: EP-FXT follow-up observation
  6. EP261030a: GROWTH-India Telescope Upper Limit
  7. EP261030a: Einstein Probe detection of a fast X-ray transient
  8. GRB 261030A: Fermi GBM Detection
  9. GRB 261029A: SVOM/ECLAIRs refined analysis
  10. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  11. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  12. GRB 261029A: Glowbug gamma-ray detection
  13. GRB 261024D: SVOM/GRM observation
  14. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  15. GRB 261029A : SVOM/GWAC-F60 observations
  16. GRB 261029A: GECAM-B detection of a bright burst
  17. The EP-WXT trigger 01709321980 is likely a flaring star
  18. GRB 261029A: WFST optical observations
  19. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  20. GRB 261029A: Ondrejov D50 optical observations, possible rebrightening
  21. GRB 261029A: Liverpool Telescope observations
  22. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  23. GRB 261029A: Fermi GBM Observation
  24. GRB 261029A: SVOM/GRM observation of a bright burst
  25. GRB261029A: Infrared fading detected with MDM/MIRAGE
  26. GRB 261029A: SVOM/VT optical observation
  27. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  28. GRB 261029A : AstroSat CZTI detection
  29. GRB 261029A: SVOM/C-GFT optical observations
  30. EP261010a: Xinglong optical follow-up
  31. GRB 261029A: EP-FXT follow-up observation
  32. GRB 261029A: LCO optical observations (correction to GCN 46082)
  33. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  34. GRB 261029A: LCO optical observations
  35. GRB261029A: Early infrared detection with MDM/MIRAGE
  36. GRB 261029A: KAIT optical observations
  37. GRB 261029A: TRT optical observations
  38. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  39. EP261025a: EP-FXT follow-up observations
  40. GRB 261029A: SVOM detection of a burst
  41. GRB 261021A: Glowbug gamma-ray detection
  42. GRB 261026A: SVOM/ECLAIRs refined analysis
  43. GRB 261026B: AstroSat CZTI detection
  44. GRB261026A: Infrared detection with MDM/MIRAGE
  45. GRB 261026A: SAO RAS optical observations
  46. The EP-WXT trigger 01709321750 is likely a flaring star
  47. GRB 261026A: EP-FXT follow-up observation
  48. GRB 261024A: SVOM/GRM observation
  49. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  50. EP 261025a: J-band upper limit with MIRAGE
  51. GRB 261024D: Glowbug gamma-ray detection
  52. GRB 261026A: Ondrejov D50 optical limit
  53. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  54. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  55. GRB 261026A: WINTER J-band observations
  56. GRB 261024D: AstroSat CZTI detection of a long burst
  57. GRB 261019A: GECAM-B observation
  58. GRB 261019A: SVOM/GRM observation
  59. GRB 261026A: KAIT optical observations
  60. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  61. GRB 261026A: SVOM detection of a burst
  62. EP261025a: J-band upper limit with WINTER
  63. EP261023a: J-band upper limit with WINTER
  64. EP 261025a: COLIBRÍ optical upper limit
  65. EP261025a: Einstein Probe detection of a fast X-ray transient
  66. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  67. EP261015a: VST optical observations
  68. EP261023a: Mondy optical upper limit
  69. EP261015a: MAO/AZT-22 optical observations
  70. EP261015a: VLA non-detection
  71. EP261023a: NOT optical counterpart candidate
  72. EP261023a: Einstein Probe detection of an X-ray transient
  73. The EP-WXT trigger 01709321472 is likely a flaring star
  74. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  75. NuSTAR 261020, a 830s hard X-ray transient
  76. EP261015a: GSP multiband optical follow-up observations
  77. GRB 261017A: SVOM/GRM observation
  78. EP261015a: Further optical observations with the 1.3m DFOT
  79. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  80. EP261015a: AZT-20 Assy-Turgen optical observations
  81. GRB 261020A: Fermi GBM Observation
  82. GRB 261017A: SAO RAS optical upper limit
  83. EP261015a: Follow-up with the 1.3m DFOT
  84. EP261015a: Terskol Zeiss-2000 optical upper limit
  85. EP261007b: Further EP-FXT follow-up observations
  86. GRB 261017A: COLIBRÍ optical upper limit
  87. EP261015a: COLIBRÍ optical observations of a rebrightening
  88. Konus-Wind detection of GRB 261017A
  89. GRB 261017A: Possible Swift/UVOT Detection
  90. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  91. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  92. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  93. EP261015b: NOT Optical Observations
  94. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  95. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  96. GRB 261017A : MITSuME Akeno optical upper limits
  97. GRB 261017A: Swift-XRT refined Analysis
  98. GRB 261017A: Nanshan/NEXT optical upper limit
  99. GRB 261017A: Enhanced Swift-XRT position
  100. GRB 261017A: Fermi GBM Observation

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