In this paper, we extend the Romanowsky and Fall (2012) results concerning the stellar angular momentum to the mass range 10(3) less than or similar to M-*/M-circle dot less than or similar to 10(12), and using this result, we calculate the inner slope, alpha of haloes density profiles in terms of V-rot, by using a previous model of Del Popolo, taking into account the interactions between dark matter and baryons through dynamical friction. Using the McConnachie sample, and that of Romanowsky and Fall, based only on observations, we show that in the quoted sample the rotationally supported galaxies, and the pressure supported ones are divided by a break at M-* similar or equal to 10(7.8) M-circle dot. Then we show that the slope alpha flattens monotonically, from alpha similar or equal to -1 to alpha similar or equal to 0. The flattening is due to the increase of specific angular momentum moving from MilkyWay-type galaxies to disk dwarf galaxies. Since at M-* < 10(7.8) M-circle dot, non-rotational supported galaxies start to dominate, the inner slope steepens again. The paper also extends the main result of Del Popolo (2016) to morphologies different from spheroids, and disks, taking into account the different morphologies delimited by the quoted ones. We finally compared our results with Di Cintio SPH simulations. The two models differ mainly at stellar masses smaller than M-* less than or similar to 10(7.8) M-circle dot. In our model the inner slope is flatter than in simulations. This imply that even finding a cored, alpha similar or equal to 0.4, profile in dSphs with masses slightly smaller than similar or equal to 10(6) M-circle dot will not imply necessarily a problem for the.CDM mode, as predicted by some simulations. To check which one of the two model was better describing data in this region, we used the LITTLE THINGS data, and compared the two models through a chi(2), finding that our model gives a better description of the data

Angular Momentum Distribution in Galaxies and Inner Haloes Profile

Del Popolo, A.
2019

Abstract

In this paper, we extend the Romanowsky and Fall (2012) results concerning the stellar angular momentum to the mass range 10(3) less than or similar to M-*/M-circle dot less than or similar to 10(12), and using this result, we calculate the inner slope, alpha of haloes density profiles in terms of V-rot, by using a previous model of Del Popolo, taking into account the interactions between dark matter and baryons through dynamical friction. Using the McConnachie sample, and that of Romanowsky and Fall, based only on observations, we show that in the quoted sample the rotationally supported galaxies, and the pressure supported ones are divided by a break at M-* similar or equal to 10(7.8) M-circle dot. Then we show that the slope alpha flattens monotonically, from alpha similar or equal to -1 to alpha similar or equal to 0. The flattening is due to the increase of specific angular momentum moving from MilkyWay-type galaxies to disk dwarf galaxies. Since at M-* < 10(7.8) M-circle dot, non-rotational supported galaxies start to dominate, the inner slope steepens again. The paper also extends the main result of Del Popolo (2016) to morphologies different from spheroids, and disks, taking into account the different morphologies delimited by the quoted ones. We finally compared our results with Di Cintio SPH simulations. The two models differ mainly at stellar masses smaller than M-* less than or similar to 10(7.8) M-circle dot. In our model the inner slope is flatter than in simulations. This imply that even finding a cored, alpha similar or equal to 0.4, profile in dSphs with masses slightly smaller than similar or equal to 10(6) M-circle dot will not imply necessarily a problem for the.CDM mode, as predicted by some simulations. To check which one of the two model was better describing data in this region, we used the LITTLE THINGS data, and compared the two models through a chi(2), finding that our model gives a better description of the data
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/374605
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