A new deep Hi survey of the galaxy Messier 33 is presented, based on observations obtained at the Dominion Radio Astrophysical Observatory. We observe a perturbed outer gas distribution and kinematics in M33, and confirm the disk warping as a significant kinematical twist of the major axis of the velocity field, though no strong tilt is measured, in agreement with previous work. Evidence for a new low brightness Hi component with anomalous velocity is reported. It harbours a large velocity scatter, as its kinematics both exceeds and lags the rotation of the disk, and leaks in the forbidden velocity zone of apparent counter-rotation. The observations also reveal wide and multiple peak Hi profiles which can be partly explained by crowded orbits in the framework of the warp model. Asymmetric motions are identified in the velocity field, as possible signatures of a lopsided potential and the warp. The mass distribution modeling of the hybrid Hα-Hi rotation curve favours a cuspy dark matter halo with a concentration in disagreement with the ΛCDM dark halo mass-concentration relationship. The total mass enclosed in 23 kpc is 8 10 10 M , of which 11% are stars and gas. At the virial radius of the cuspy halo, the resulting total mass is 5 10 11 M , but with a baryonic mass fraction of 2% only. This strongly suggests a more realistic radius encompassing the total mass of M33 well smaller than the virial radius of the halo, maybe comparable to the size of the Hi disk.

As part of a long-term project to revisit the kinematics and dynamics of the large disc galaxies of the Local Group, we present the first deep, wide-field (∼ 42 × 56 ) 3D-spectroscopic survey of the ionized gas disc of Messier 33. Fabry-Perot interferometry has been used to map its Hα distribution and kinematics at unprecedented angular resolution ( 3 ) and resolving power (∼ 12600), with the 1.6 m telescope at the Observatoire du Mont Mégantic. The ionized gas distribution follows a complex, large-scale spiral structure, unsurprisingly coincident with the already-known spiral structures of the neutral and molecular gas discs. The kinematical analysis of the velocity field shows that the rotation center of the Hα disc is distant from the photometric center by ∼ 170 pc (sky projected distance) and that the kinematical major-axis position angle and disc inclination are in excellent agreement with photometric values. The Hα rotation curve agrees very well with the Hi rotation curves for 0 < R < 6.5 kpc, but the Hα velocities are 10 − 20 km s −1 higher for R > 6.5 kpc. The reason for this discrepancy is not well understood. The velocity dispersion profile is relatively flat around 16 km s −1 , which is at the low end of velocity dispersions of nearby star-forming galactic discs. A strong relation is also found between the Hα velocity dispersion and the Hα intensity. Mass models were obtained using the Hα rotation curve but, as expected, the dark matter halo's parameters are not very well constrained since the optical rotation curve only extends out to 8 kpc.

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. The kinetics and drying rates are determined according to the temperature and velocity of the drying air. The equation of "Gaussian", used for the first time and in this work, is more adaptable to the drying curves. Two methods have been used to determine the coefficient of effective diffusion (with and without the effect of shrinkage). The energy of activation is evaluated with the Arrhenius relationship. In this study, we are interested in the phenomenon of shrinkage, in particular, and the evolution of the relative thickness of the slice of tomato according to drying duration and moisture content. The study shows that on hot air drying, the influence of velocity is dominant as compared to temperature. We observed that for the same final moisture content, the final relative thickness of the product is not constant. It varies depending on the operating conditions.

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For the Local Group Scd galaxy M 33 this paper presents a multi-scale study of the relationship between the monochromatic star formation rate (SFR) estimator based on 12 µm emission and the total SFR estimator based on a combination of far-ultraviolet and 24 µm emission. We show the 12 µm emission to be a linear estimator of total SFR on spatial scales from 782 pc down to 49 pc, over almost four magnitudes in SFR. These results therefore extend to sub-kpc length scales the analogous results from other studies for global length scales. We use high-resolution H i and 12 CO(J = 2 − 1) image sets from the literature to compare the star formation to the neutral gas. For the full range of length scales we find well-defined power-law relationships between 12 µm-derived SFR surface densities and neutral gas surface densities. For the H 2 gas component almost all correlations are consistent with being linear. No evidence is found for a breakdown in the star formation law at small length-scales in M 33 reported by other authors. We show that the average star formation efficiency in M 33 is roughly 10 −9 yr −1 and that it remains constant down to giant molecular cloud lengthscales. Toomre and shear-based models of the star formation threshold are shown to inaccurately account for the star formation activity in the inner disc of M 33. Finally, we clearly show that the H i saturation limit of ≈ 9 M ⊙ pc −2 reported in the literature for other galaxies is not an intrinsic property of M 33 -it is systematically introduced as an artefact of spatially smoothing the data.

Context. The ellipsoid of random motions of the gaseous medium in galactic disks is often considered isotropic, as appropriate if the gas is highly collisional. However, the collisional or collisionless behavior of the gas is a subject of debate. If the gas is clumpy with a low collision rate, then the often observed asymmetries in the gas velocity dispersion could be hints of anisotropic motions in a gaseous collisionless medium. Aims. We study the properties of anisotropic and axisymmetric velocity ellipsoids from maps of the gas velocity dispersion in nearby galaxies. This data allow us to measure the azimuthal-to-radial axis ratio of gas velocity ellipsoids, which is a useful tool to study the structure of gaseous orbits in the disk. We also present the first estimates of perturbations in gas velocity dispersion maps by applying an alternative model that considers isotropic and asymmetric random motions. Methods. High-quality velocity dispersion maps of the atomic medium at various angular resolutions of the nearby spiral galaxy Messier 33, are used to test the anisotropic and isotropic velocity models. The velocity dispersions of hundreds of individual molecular clouds are also analyzed. Results. The HI velocity dispersion of M 33 is systematically larger along the minor axis, and lower along the major axis. Isotropy is only possible if asymmetric motions are considered. Fourier transforms of the H I velocity dispersions reveal a bisymmetric mode which is mostly stronger than other asymmetric motions and aligned with the minor axis of the galaxy. Within the anisotropic and axisymmetric velocity model, the stronger bisymmetry is explained by a radial component that is larger than the azimuthal component of the ellipsoid of random motions, thus by gaseous orbits that are dominantly radial. The azimuthal anisotropy parameter is not strongly dependent on the choice of the vertical dispersion. The velocity anisotropy parameter of the molecular clouds is observed highly scattered. Conclusions. Perturbations such as HI spiral-like arms could be at the origin of the gas velocity anisotropy in M 33. Further work is necessary to assess whether anisotropic velocity ellispsoids can also be invoked to explain the asymmetric gas random motions of other galaxies.

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