tokens: : pseudo-ADI image of the inner regions obtained by differentiating the Q Φ image (see Ligi et al. 2018 , for more details). The white cross marks the position of the star, and the cyan circle shows the size of the coronagraphic mask. The other labels refer to the blobs we discuss in this paper that are also visible in these images. Thecolor scale of the differential image is five times less extended to show the faint structures better. In both panels, N is up and E to the left; a segment represents 1 and 0.5 arcsec in the left and right panel, respectively. Fig. 2 Signal-to-noise ratio (S/N) maps for the individual epochs for IFS. The individual S/N maps are obtained from the ASDI PCA algorithm using 50 components and making a median over the wavelength (see Mesa et al. 2015 ). Upper row, left panel : JD = 57180.17, middle panel : JD = 57201.12, and right panel : JD = 57499.34. Lower row, left panel : JD = 57566.15, middle panel : JD = 57873.30, and right panel : JD = 58288.19. In all panels, the central 0.1 arcsec is masked, the solid white line at the bottom represents 1 arcsec, the white cross represents the position of the star. N is up and E to the left. The upper panels of Fig. 3 show images of HD 169142 obtained by combining the six individual images, assuming the distance given by Gaia DR2, a mass of 1.7 M ⊙ (see below), and circular orbits. 3.1 Coincidence images To improve our ability of discerning faint signals, we combined data from different epochs using a coincidence map (see the lower panel of Fig. 3 ). The principle of this coincidence map is to start with S/N maps for individual epochs. We used S/N maps after correcting for the small-number-statistics effect using the formula by Mawet et al. (2014) . The maps were then multiplied by each other. The S/N maps average to zero, with both positive and negative values for individual pixels. Of course, this may result in a false-positive signal for an even number of negative signals in the individual S/N maps. To avoid this problem, we arbitrarily set to negative the result for a given pixel when the signal for that pixel was negative for at least one epoch. Of course, this is not a realistic flux map: the aim is merely to identify consistent signals throughout all individual images. To consider the orbital motion around the star over the three years covered by our observations, we divided the field into 65 rings, each one 2 IFS pixels wide (15 mas, i.e., about 1.8 au at the distance of HD 169142). For each ring, we rotated the S/N maps obtained at different epochs with respect to the first reference image according to Kepler’s third law. When the distance to the star was fixed, the only free parameter remaining in this model is the (dynamical) stellar mass. If there is a companion orbiting the star, the signal is maximized for a value of the mass that, if the assumptions made (circular motion seen face on) are correct, is the dynamical mass of the star. If these hypotheses are not
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