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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"

27647 results found.

  1. EP261030a: GROWTH-India Telescope Upper Limit
  2. GRB 261101A: Fermi GBM Final Real-time Localization
  3. EP261030a: Global MASTER-Net observations report
  4. GRB 261030A: Fermi GBM Detection
  5. Fermi GRB 261030B: Global MASTER-Net observations report
  6. GRB 261030B: Fermi GBM Final Real-time Localization
  7. GRB 261029A: SVOM/ECLAIRs refined analysis
  8. The EP-WXT trigger 01709321980: KAIT confirmation of a stellar flare
  9. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  10. GRB 261030A: Fermi GBM Final Real-time Localization
  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 261029A : SVOM/GWAC-F60 observations
  15. EP-WXT trigger 01709321980: confirmation of a stellar flare by BOOTES-5
  16. The EP-WXT trigger 01709321980 is likely a flaring star
  17. EP Alert 261030.22: Global MASTER-Net observations report
  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: Optical detection with 60cm Panzhihua Telescope
  21. GRB 261029A: Fermi GBM Observation
  22. GRB 261029A: FRAM-ORM and FRAM-Auger optical afterglow light curve
  23. GRB 261029A: SVOM/GRM observation of a bright burst
  24. GRB 261029A: CALET Gamma-Ray Burst Monitor detection
  25. GRB261029A: Infrared fading detected with MDM/MIRAGE
  26. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  27. GRB 261029A: SVOM/C-GFT optical observations
  28. GRB 261029A: EP-FXT follow-up observation
  29. GRB 261029A: Fermi-LAT detection
  30. GRB 261029A: LCO optical observations (correction to GCN 46082)
  31. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  32. GRB 261029A: LCO optical observations
  33. GRB 261029A: NOT imaging and spectroscopic redshift z = 3.27
  34. GRB261029A: Early infrared detection with MDM/MIRAGE
  35. GRB 261029A: KAIT optical observations
  36. GRB 261029A: TRT optical observations
  37. GRB 261029B: Fermi GBM Final Real-time Localization
  38. GRB 261029A: GOTO optical counterpart candidate
  39. GRB 261029A: SVOM detection of a burst
  40. GRB 261029A: Fermi GBM Final Real-time Localization
  41. GRB 261028A: Fermi GBM Final Localization
  42. GRB 261026A: SVOM/ECLAIRs refined analysis
  43. GRB 261024C: GECAM-B observation
  44. GRB261026A: Infrared detection with MDM/MIRAGE
  45. GRB 261026A: SVOM/VT optical blue bump
  46. GRB 261024D: GECAM-B observation
  47. The EP-WXT trigger 01709321750 is likely a flaring star
  48. EP Alert 261026.29: Global MASTER-Net observations report
  49. GRB 261026A: EP-FXT follow-up observation
  50. GRB 261024A: SVOM/GRM observation
  51. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  52. EP 261025a: J-band upper limit with MIRAGE
  53. GRB 261026A: OHP/T120 optical imaging
  54. GRB 261026A: Ondrejov D50 optical limit
  55. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  56. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  57. GRB 261026A: SVOM/VT optical observations
  58. GRB 261026C: Fermi GBM Final Real-time Localization
  59. SVOM GRB261026.26: Global MASTER-Net observations report
  60. GRB 261026A: WINTER J-band observations
  61. Fermi GRB 261026B: Global MASTER-Net observations report
  62. GRB 261026A: SVOM/VT optical observation from VHF data
  63. GRB 261026A: KAIT optical observations
  64. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  65. GRB 261026B: Fermi GBM Final Real-time Localization
  66. GRB 261026A: SVOM detection of a burst
  67. GRB 261025B: Fermi GBM Final Real-time Localization
  68. EP261023a: J-band upper limit with WINTER
  69. EP 261025a: COLIBRÍ optical upper limit
  70. GRB 261025A: Fermi GBM Final Localization Correction
  71. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  72. GRB 261024B: Fermi GBM Final Real-time Localization
  73. EP261015a: VST optical observations
  74. GRB 261024A: BALROG localization (Fermi Trigger 814551785 / GRB 261024683)
  75. GRB 261024A: Fermi GBM Final Real-time Localization
  76. EP261023a: Mondy optical upper limit
  77. EP261015a: VLA non-detection
  78. EP261023a: NOT optical counterpart candidate
  79. EP261023a: Einstein Probe detection of an X-ray transient
  80. The EP-WXT trigger 01709321472 is likely a flaring star
  81. GRB 261021A: Fermi GBM Final Real-time Localization
  82. EP261015a: AZT-20 Assy-Turgen optical observations
  83. GRB 261020A: Fermi GBM Observation
  84. EP261015a: Wendelstein 43 cm optical observations
  85. GRB 261017A: COLIBRÍ optical upper limit
  86. GRB 261020A: MAXI GSC detection
  87. GRB 261020A: Fermi GBM Final Real-time Localization
  88. EP261015a: COLIBRÍ optical observations of a rebrightening
  89. Konus-Wind detection of GRB 261017A
  90. GRB 261019A: Fermi GBM Final Localization
  91. GRB 261017A: Possible Swift/UVOT Detection
  92. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  93. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  94. GRB 261017A: Swift-BAT refined analysis
  95. EP261015b: NOT Optical Observations
  96. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  97. GRB 261017A : MITSuME Akeno optical upper limits
  98. GRB 261017A: Swift-XRT refined Analysis
  99. GRB 261017A: Fermi GBM Observation
  100. GRB 261017A: Swift detection of a burst

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