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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"

28359 results found.

  1. GRB 261108D: DECam optical detection of candidate afterglow
  2. GRB 261108D: PRIME near-infrared candidate
  3. EP261105A: Gemini-South/GMOS Optical Upper Limit
  4. GRB 261101A: SVOM/GRM observation
  5. EP Alert 261109.41: Global MASTER-Net observations report
  6. The EP-WXT trigger 01709322330 is likely a AGN
  7. EP261105a: Second EP-FXT follow-up observation
  8. GRB 261108C: SVOM/VT early optical upper limits
  9. GRB 261108C: LCO optical upper limits
  10. SVOM GRB261108.99: Global MASTER-Net observations report
  11. SVOM GRB261108.89: Global MASTER-Net observations report
  12. GRB 261108C: SVOM detection of a burst
  13. GRB 261108A: Fermi GBM Observation
  14. GRB 261108A: SVOM/C-GFT optical upper limit
  15. GRB 261108A: SVOM/VT optical upper limits
  16. Fermi trigger No 815809059: Global MASTER-Net observations report
  17. EP261105a: VLT/HAWK-I nIR detection
  18. GRB 261108A: LCO optical upper limits
  19. GRB 261108A: FRAM-Auger optical limits
  20. SVOM GRB261108.05: Global MASTER-Net observations report
  21. EP-WXT trigger 01709322272 : SVOM/C-GFT confirmation of a stellar flare
  22. EP Alert 261106.89: Global MASTER-Net observations report
  23. GRB 261029C: SVOM/GRM detection of a short burst
  24. EP-WXT trigger 01709322274: Ondrejov D50 detection of a likely stellar flare
  25. EP Alert 261106.58: Global MASTER-Net observations report
  26. EP261105a: PRIME near-infrared upper limit
  27. EP261105a: VLT/FORS2 optical detection
  28. EP Alert 261105.81: Global MASTER-Net observations report
  29. EP261105a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  30. EP261103a: refined WXT analysis and FXT follow-up observations
  31. GRB 261104A：EP-FXT follow-up observation
  32. EP261105a: Global MASTER-Net observations report
  33. GRB 261104A: DECam Detection of an Optical Counterpart Candidate
  34. GRB 261104A: SVOM/ECLAIRs refined analysis
  35. EP261105a: LCO optical upper limits
  36. EP261105a: SVOM/VT optical candidate
  37. IPN triangulation of GRB 261029C (short / bright)
  38. GRB 261103A: SVOM/C-GFT optical upper limit
  39. EP261105a: Einstein Probe detection of an X-ray transient
  40. GRB 261104A: LCO optical upper limits
  41. SVOM GRB261104.86: Global MASTER-Net observations report
  42. EP241208a: SVOM/ECLAIRs refined analysis
  43. GRB 261104A: SVOM detection of burst
  44. GRB 260924A: CrAO ZTSh optical observations
  45. EP261103a: NTT optical observation
  46. GRB 261029A : MITSuME Akeno optical afterglow detection
  47. EP261103a: SVOM/VT optical observation
  48. EP261103a: NOT optical counterpart candidate
  49. EP261103a: Einstein Probe detection of an X-ray transient
  50. GRB 261029A: VST/OmegaCAM detection of the optical afterglow at 3 days
  51. EP Alert 261103.85: Global MASTER-Net observations report
  52. GRB 261029A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  53. GRB 261103A: LCO optical upper limits
  54. EP Alert 261102.98: Global MASTER-Net observations report
  55. GRB 261029A: SAO RAS optical observations
  56. GRB 261102A: Fermi GBM Detection
  57. GRB 261101B: BALROG localization (Fermi Trigger 815240277 / GRB 261101651)
  58. GRB 261101B: Fermi GBM Final Real-time Localization
  59. EP261030a: EP-FXT follow-up observation
  60. EP261030a: GROWTH-India Telescope Upper Limit
  61. GRB 261101A: Fermi GBM Final Real-time Localization
  62. EP261030a: Global MASTER-Net observations report
  63. EP261030a: Einstein Probe detection of a fast X-ray transient
  64. GRB 261030A: Fermi GBM Detection
  65. Fermi GRB 261030B: Global MASTER-Net observations report
  66. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  67. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  68. GRB 261029A: Glowbug gamma-ray detection
  69. GRB 261024D: SVOM/GRM observation
  70. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  71. GRB 261029A : SVOM/GWAC-F60 observations
  72. EP Alert 261030.22: Global MASTER-Net observations report
  73. GRB 261029A: WFST optical observations
  74. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  75. GRB 261029A: Ondrejov D50 optical observations, possible rebrightening
  76. GRB 261029A: NuSTAR detection of bright prompt emission
  77. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  78. GRB 261029A: Fermi GBM Observation
  79. GRB 261029A: FRAM-ORM and FRAM-Auger optical afterglow light curve
  80. GRB261029A: Infrared fading detected with MDM/MIRAGE
  81. GRB 261029A: SVOM/VT optical observation
  82. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  83. GRB 261029A : AstroSat CZTI detection
  84. GRB 261029A: SVOM/C-GFT optical observations
  85. EP261010a: Xinglong optical follow-up
  86. GRB 261029A: EP-FXT follow-up observation
  87. GRB 261029A: LCO optical observations (correction to GCN 46082)
  88. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  89. GRB 261029A: LCO optical observations
  90. GRB261029A: Early infrared detection with MDM/MIRAGE
  91. GRB 261029A: KAIT optical observations
  92. GRB 261029A: TRT optical observations
  93. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  94. EP261025a: EP-FXT follow-up observations
  95. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  96. GRB 261021A: Glowbug gamma-ray detection
  97. GRB261026A: Infrared detection with MDM/MIRAGE
  98. GRB 261026A: SAO RAS optical observations
  99. EP Alert 261026.29: Global MASTER-Net observations report
  100. GRB 261026A: EP-FXT follow-up observation

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