اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدThe dark matter halo density profile, spiral arm morphology and black hole mass of M33
191
0
0.0
(
0
)
تأليف
Marc S. Seigar
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
In this paper, we investigate the dark matter halo density profile of M33. We find that the HI rotation curve of M33 is best described by a NFW dark matter halo density profile model, with a halo concentration of cvir = 4.0pm1.0 and a virial mass of Mvir = (2.2pm0.1)times10^11 Msun. We go on to use the NFW concentration (cvir)of M33, along with the values derived for other galaxies (as found in the literature), to show that cvir correlates with both spiral arm pitch angle and supermassive black hole mass.
قيم البحث
اقرأ أيضاً
We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well-correlated with the rate of shear (S) in disk galaxy rotation curves, by using a much
larger sample (51 galaxies) than used previously (17 galaxies). We use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large lookback times. In contrast to previous work, we show that observed spiral arm pitch angles are similar when measured in the optical (at 0.4 um) and the near-infrared (at 2.1 um) with a mean difference of 2.3+/-2.7 degrees. This is then used to strengthen the known correlation between P and S using B-band images. We then use two example galaxies to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher derived velocity normalization can be used to place constraints on a galaxys baryon fraction and dark matter halo profile. We show that ESO 582-G12, a galaxy with a high shear rate (slightly declining rotation curve) at ~10 kpc, favors an adiabatically contracted halo, with high initial NFW concentration (c_vir > 16) and a high fraction of halo baryons in the form of stars (~15-40%). In contrast, IC 2522 has a low shear rate (rising rotation curve) at ~10 kpc and favors non-adiabatically contracted models with low NFW concentrations (c_vir ~ 2-8) and a low stellar baryon fraction <10%.
We present a relationship between spiral arm pitch angle (a measure of the tightness of spiral structure) and the mass of supermassive black holes (BHs) in the nuclei of disk galaxies. We argue that this relationship is expected through a combination
of other relationships, whose existence has already been demonstrated. The recent discovery of AGN in bulgeless disk galaxies suggests that halo concentration or virial mass may be one of the determining factors in BH mass. Taken together with the result that mass concentration seems to determine spiral arm pitch angle, one would expect a relation to exist between spiral arm pitch angle and supermassive BH mass in disk galaxies, and we find that this is indeed the case. We conclude that this relationship may be important for estimating evolution in BH masses in disk galaxies out to intermediate redshifts, since regular spiral arm structure can be seen in galaxies out to z~1.
We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of shear (S) in disk galaxy rotation curves. We use this corr
elation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large look-back times. We then use a sample of 13 galaxies, with Spitzer 3.6-$mu$m imaging data and observed H$alpha$ rotation curves, to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher-derived velocity normalization can be used to place constraints on a galaxys baryon fraction and dark matter halo profile. Finally we show that there appears to be a trend (albeit a weak correlation) between spiral arm pitch angle and halo concentration. We discuss implications for the suggested link between supermassive black hole (SMBH) mass and dark halo concentration, using pitch angle as a proxy for SMBH mass.
We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular cluster velocit
ies out to 8 effective radii. We simultaneously fit for four parameters, black hole mass, dark halo core radius, dark halo circular velocity, and stellar mass-to-light ratio. We find a black hole mass of 6.4(+-0.5)x10^9 Msun(the uncertainty is 68% confidence marginalized over the other parameters). The stellar M/L_V=6.3+-0.8. The best-fitted dark halo core radius is 14+-2 kpc, assuming a cored logarithmic potential. The best-fitted dark halo circular velocity is 715+-15 km/s. Our black hole mass is over a factor of 2 larger than previous stellar dynamical measures, and our derived stellar M/L ratio is 2 times lower than previous dynamical measures. When we do not include a dark halo, we measure a black hole mass and stellar M/L ratio that is consistent with previous measures, implying that the major difference is in the model assumptions. The stellar M/L ratio from our models is very similar to that derived from stellar population models of M87. The reason for the difference in the black hole mass is because we allow the M/L ratio to change with radius. The dark halo is degenerate with the stellar M/L ratio, which is subsequently degenerate with the black hole mass. We argue that dynamical models of galaxies that do not include the contribution from a dark halo may produce a biased result for the black hole mass. This bias is especially large for a galaxy with a shallow light profile such as M87, and may not be as severe in galaxies with steeper light profiles unless they have a large stellar population change with radius.
We investigate a possibility of primordial black hole (PBH) formation with a hierarchical mass spectrum in multiple phases of inflation. As an example, we find that one can simultaneously realize a mass spectrum which has recently attracted a lot of
attention: stellar-mass PBHs ($simmathcal{O}(10)M_odot$) as a possible source of binary black holes detected by LIGO/Virgo collaboration, asteroid-mass ($simmathcal{O}(10^{-12})M_odot$) as a main component of dark matter, and earth-mass ($simmathcal{O}(10^{-5})M_odot$) as a source of ultrashort-timescale events in Optical Gravitational Lensing Experiment microlensing data. The recent refined de Sitter swampland conjecture may support such a multi-phase inflationary scenario with hierarchical mass PBHs as a transition signal of each inflationary phase.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
