Discovery of Unusual Jet Orientation Variations in the Microquasar GRS 1915+105

Top: radio light curves of GRS1915+105 from January to March 2025, observedwithRATAN at 2.3 and 4.7GHz (top), together with the corresponding spectral index (bottom), defined as α=log(S2/S1)/log(ν2/ν1). No data are available between MJD 60723 and 60726. Four radio flares are identified, peaking at MJD 60690.4±1(FlareI), 60700.0±1(FlareII), 60711.3±1(FlareIII), and 60722.4±1(FlareIV). Our EAVN epochs (A, B, and F) are also marked at the top of the x-axis, with the corresponding VLBI total flux densities overlaid. Bottom: EAVN 6.7GHz phase-referenced images of GRS1915+105 obtained in 2025. All  images share the same color bar, as indicated in the epoch A image. The FWHM of the synthesized beam is shown in the lower-left corner of each panel. Contours are drawn starting at ±3Irms and increase by successive factors of 2. Dashed contours represent negative levels. The magenta circles show the position and FWHM of the model-fitted circular Gaussian components. The magenta dashed line indicates the jet orientation (i.e., PA) derived from the component relative distances, while the blue dashed line represents the typical orientation for the south east–north west jet, with ⟨PA⟩=147°±8° (L.F.Rodrıguez & I.F.Mirabel 2025). The magenta cross marks  the extrapolated position of GRS1915+105 on January  1 2025 (19h 15m 11s.5437 ± 1.0mas, +10°56′44.′′594 ± 1.3mas), as derived from the source coordinates on 2000 January 1 and its proper motion.The magenta dots correspond to the image intensity peak of epoch A at∼(−2.4, −2.0) mas, which is where the core is located.