a) The initial rotation curves of the stellar disk; b) the initial disk surface density; c) the final rotation curve at 9.78 Gyr; d) the Toomre parameter variation with radius for all the models

Contexts in source publication

Context 1

... how bulge mass affects bar formation (Kataria & Das 2018) (hereafter KD2018). We found that for a given disk scale length, bars are more difficult to form in disks with massive bulges and the bar pattern speed (Ω p ) increases with bulge mass. The gravity of the central bulge can affect the bar pattern speed. This is clearly shown in Fig. 8 and Fig. 12 of KD2018. In this paper we present a more detailed study of how bulge mass affects Ω p and especially its evolution with time (dΩ p /dt). There have been several theoretical studies that indicate that Ω p slows down over time. Lynden-Bell (1979) discussed that bars capture orbits as they evolve and transfer angular momentum from the ...

Context 2

... 2008). It has been shown that the effect of cuspy bulges is that the ILR disappears in thick disks ( Polyachenko et al. 2016), which is the case in the present work. Apart from disk thickness there are other factors like nonlinear processes ( Widrow et al. 2008) and the inner Q barrier (Bertin 2014) which can put off the effect of an ILR. Fig. 1 shows the initial and final rotation curves as well as the variation of initial surface density and initial Toomre parameter with radius for all of our models. We see that the inner part of the rotation curve rises with increase in bulge mass fraction which is not the case for the final evolved models which we discuss in section 3.6. ...

Context 3

... formed, it goes into the secular evolution phase in all models. In this phase the bar strengths increase except for Model 3 and Model 4 where it is almost constant as the galaxy evolves. The final X- Figure 8. The absolute value of Rate of change in pattern speed of bar with time for all the models Y cross sections for all the models is shown in Fig. 10 where we can see that the final bars have similar morphologies. This trend matches that of the bar strength plot shown in Fig. 9, where nearly all the bars have similar A 2 /A 0 values with only small variations. Thus increasing the bulge does not strongly affect the final bar strength as the final values vary by A 2 /A 0 <= ...

Context 4

... increasing ellipticity corresponds to the continuous slowdown of Ω p (Fig. 7). However, for the bulge dominated models (Model 2, Model 3, Model 4 and Model 5), the bar ellipticity increases continuously with time in the beginning but hovers around a mean Model 5 Figure 10. X-Y cross section of all the evolved models at 9.78 Gyr. ...

Context 5

... can physically interpret this correlation in the following way; as the eccentricity of the stellar orbits in the bar increases, the bar strength also increases. This is clearly seen in Figure 11 which shows the bar ellipticity evolution with time for all the models. We can also see that the final ellipticity of the bars at the end of the simulation decreases as bulge mass increases progressively from the bulgeless model (Model 1) to the most bulge dominated model (Model 5). ...

Context 6

... disk evolution, the angular momentum of the bulge can change with time and this may affect the bar pattern speed. To investigate this we plotted the evolution of total angular momentum with time for bulge, disk and halo components for all the models in Fig. 12. A similar analysis was done in (KD2018). We find that the bulge and halo components always gain angular momentum with time for all the bar forming models, while the disk component always loses angular momentum The rate of change in angular momentum of the components (bulge, disk, halo) only increases after the bar has been triggered ...

Context 7

... (bulge, disk, halo) only increases after the bar has been triggered and hence the bar is important for the angular momentum exchange. As the inner disk transfers the angular momentum to the halo and bulge components, the rotation velocities of the inner disk stars decreases, this is clearly seen in the initial and final rotation curves shown in Fig. ...

Context 8

... this section we discuss the implications of our results for the observations of bars. It is clear from Fig. 12 that a bar transfers a significant amount of angular momentum to a non-rotating classical bulge and the angular momentum transfer increases with bulge mass. The interaction is similar to the resonance between orbits in the halo and the bar pattern speed Ω p (Holley- Bockelmann et al. 2005), only in this case it is the resonant ...

Context 9

... how bulge mass affects bar formation (Kataria & Das 2018) (hereafter KD2018). We found that for a given disk scale length, bars are more difficult to form in disks with massive bulges and the bar pattern speed (Ω p ) increases with bulge mass. The gravity of the central bulge can affect the bar pattern speed. This is clearly shown in Fig. 8 and Fig. 12 of KD2018. In this paper we present a more detailed study of how bulge mass affects Ω p and especially its evolution with time (dΩ p /dt). There have been several theoretical studies that indicate that Ω p slows down over time. Lynden-Bell (1979) discussed that bars capture orbits as they evolve and transfer angular momentum from the ...

Context 10

... 2008). It has been shown that the effect of cuspy bulges is that the ILR disappears in thick disks ( Polyachenko et al. 2016), which is the case in the present work. Apart from disk thickness there are other factors like nonlinear processes ( Widrow et al. 2008) and the inner Q barrier (Bertin 2014) which can put off the effect of an ILR. Fig. 1 shows the initial and final rotation curves as well as the variation of initial surface density and initial Toomre parameter with radius for all of our models. We see that the inner part of the rotation curve rises with increase in bulge mass fraction which is not the case for the final evolved models which we discuss in section 3.6. ...

Context 11

... formed, it goes into the secular evolution phase in all models. In this phase the bar strengths increase except for Model 3 and Model 4 where it is almost constant as the galaxy evolves. The final X- Figure 8. The absolute value of Rate of change in pattern speed of bar with time for all the models Y cross sections for all the models is shown in Fig. 10 where we can see that the final bars have similar morphologies. This trend matches that of the bar strength plot shown in Fig. 9, where nearly all the bars have similar A 2 /A 0 values with only small variations. Thus increasing the bulge does not strongly affect the final bar strength as the final values vary by A 2 /A 0 <= ...

Context 12

... increasing ellipticity corresponds to the continuous slowdown of Ω p (Fig. 7). However, for the bulge dominated models (Model 2, Model 3, Model 4 and Model 5), the bar ellipticity increases continuously with time in the beginning but hovers around a mean Model 5 Figure 10. X-Y cross section of all the evolved models at 9.78 Gyr. ...

Context 13

... can physically interpret this correlation in the following way; as the eccentricity of the stellar orbits in the bar increases, the bar strength also increases. This is clearly seen in Figure 11 which shows the bar ellipticity evolution with time for all the models. We can also see that the final ellipticity of the bars at the end of the simulation decreases as bulge mass increases progressively from the bulgeless model (Model 1) to the most bulge dominated model (Model 5). ...

Context 14

... disk evolution, the angular momentum of the bulge can change with time and this may affect the bar pattern speed. To investigate this we plotted the evolution of total angular momentum with time for bulge, disk and halo components for all the models in Fig. 12. A similar analysis was done in (KD2018). We find that the bulge and halo components always gain angular momentum with time for all the bar forming models, while the disk component always loses angular momentum The rate of change in angular momentum of the components (bulge, disk, halo) only increases after the bar has been triggered ...

Context 15

... (bulge, disk, halo) only increases after the bar has been triggered and hence the bar is important for the angular momentum exchange. As the inner disk transfers the angular momentum to the halo and bulge components, the rotation velocities of the inner disk stars decreases, this is clearly seen in the initial and final rotation curves shown in Fig. ...

Context 16

... this section we discuss the implications of our results for the observations of bars. It is clear from Fig. 12 that a bar transfers a significant amount of angular momentum to a non-rotating classical bulge and the angular momentum transfer increases with bulge mass. The interaction is similar to the resonance between orbits in the halo and the bar pattern speed Ω p (Holley- Bockelmann et al. 2005), only in this case it is the resonant ...