We compare the CO(1–0) and Hα kinematics in 34 nearby galaxies, selected from the ALMaQUEST and EDGE-CALIFA surveys. We use 3D-Barolo, a 3D tilted-ring model, to derive the CO and Hα rotation curves. Before comparing rotation curves in the 34 nearby galaxies, we found systematics between the MaNGA and CALIFA data using eight MaNGA-CALIFA overlapping galaxies. We assume the rotation curves based on the MaNGA data are accurate and made the corresponding correction to the CALIFA data. Our result shows that ∼56% (19/34) of our galaxies present slower Hα rotation curves compared to the CO rotation curves, with a median value of 6.5 km s−1. The remaining galaxies (15/34) show consistent CO–Hα rotation velocity within uncertainties. As a result, the Hα rotation may underestimate the total dynamical mass by 6% for a circular velocity of 200 km s−1 (the median value in our sample). Furthermore, the difference in the velocity between the CO and Hα rotational velocity is found to correlate with the difference in velocity dispersion between CO and Hα, suggesting that gas pressure plays a role in the discrepancy in velocity. After incorporating the effect of pressure support due to the turbulent gas motion into our sample, the median value of the difference in the velocities decreases to 1.9 km s−1, which in turn reduces the underestimation of the dynamical mass to ∼2%. Finally, we also investigate the role that the extraplanar diffuse ionized gas plays in the discrepancy in the velocity of CO–Hα.
We present Multi Unit Spectroscopic Explorer (MUSE) integral-field stellar and ionized velocity maps for a sample of 14 barred galaxies. Most of these objects exhibit “S”-shape isovelocities in the bar region indicative of the presence of streaming motions in the velocity fields. By applying circular rotation models we observe that bars leave symmetric structures in the residual maps of the stellar velocity. We built noncircular rotation models using the XookSuut tool to characterize the observed velocity fields; in particular we adopt bisymmetric models and a harmonic decomposition for a bar potential for describing the nonaxisymmetric velocities. We find that both models are able to reproduce the oval distortion observed in the velocity maps. Furthermore, the position angle of the oval distortion estimated from the bisymmetric model correlates with the photometric bar position angle (ρ pearson = 0.95), which suggests that noncircular velocities are caused by the bar. Because of the weak detection of Hα in our objects we are not able to compare gas to stellar noncircular motions in our sample, although we show that when galaxies are gas-rich, oval distortion is also observed but with larger amplitudes. Finally, we do not find evidence that the amplitude of the noncircular motions is dependent on the bar size, stellar mass, or global star formation rate.
Post-starburst (PSB) galaxies have recently and rapidly quenched their star formation; thus, they are an important way to understand how galaxies transition from star-forming late types to quiescent early types. The recent discovery of large cold gas reservoirs in PSB galaxies calls into question the theory that galaxies must lose their gas to become quiescent. Optical Integral Field Spectroscopy (IFS) surveys have revealed two classes of PSB galaxies: central PSB (cPSB) galaxies with central quenching regions and ring PSB (rPSB) galaxies with quenching in their outskirts. We analyze a sample of 13 nearby (z < 0.1) PSB galaxies with spatially resolved optical IFS data from the Mapping Nearby Galaxies at Apache Point Observatory survey and matched resolution Atacama Large Millimeter/submillimeter Array observations of 12CO(1–0). Disturbed stellar kinematics in 7/13 of our PSB galaxies and centrally concentrated molecular gas is consistent with a recent merger for most of our sample. In galaxies without merger evidence, alternate processes may funnel gas inward and suppress star formation, which may include outflows, stellar bars, and minor mergers or interactions. The star formation efficiencies of the PSB regions in nearly half our galaxies are suppressed while the gas fractions are consistent with star-forming galaxies. Active galactic nucleus (AGN) feedback may drive this stabilization, and we observe AGN-consistent emission in the centers of 5/13 galaxies. Finally, our cPSB and rPSB galaxies have similar properties except the ionized and molecular gas in cPSB galaxies is more disturbed. Overall, the molecular gas in our PSB galaxies tends to be compact and highly disturbed, resulting in concentrated gas reservoirs unable to form stars efficiently.
Aims: To estimate the population density of Pecari tajacu, determine the distribution pattern of this population in the sampling sites, determine habitat preference and evaluate the sustainability of the harvest in the three-year period. Study Design: Population study of collared peccaries in the wild, descriptive, and vertical in the municipality of Tzucacab, Yucatan, Mexico, during the years 2003-2004, 2007-2008 and 2008-2009. Methodology: Seven linear transects of 5 km each were installed randomly in the municipality in 2003-2004 and 18 in each year from 2007 to 2009. The population estimate was made by direct sighting and counting of footprints in the same transects. The comparison of densities with the footprints’ counting method was by analysis of variance and t-student for samples paired with the sighting method. The distribution pattern was analyzed by the standardized Morisita index; habitat preference was analyzed by Bonferroni intervals and the harvest model was applied to evaluate sustainability. Results: Population densities decreased significantly (P < 0.01) by the footprints´ counting method from 2003-04 to 2007-09, from 1.16 to 0.26 animals/km2 respectively, with the sighting method was 1.87 and 1.78 animals/km2, the years 2003-04 and 2007-08 respectively, without significant difference (P = 0.05); In 2008-09 there was only one record. Local populations are distributed by clusters and prefer the acahual habitat between 2008-09. The sighting records and footprints are distributed mainly in the limits of the municipality of Tzucacab with the surroundings and the state of Quintana Roo. Harvest indices are within sustainability values but show a tendency to increase as the years progress. Conclusion: Local populations of collared peccaries show vulnerability, if the trend of the harvest index increases progressively.
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