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We determine X-ray temperatures and abundances for elliptical galaxies drawn from a complete, optically selected sample. The optical magnitude-limited sample consists of 43 galaxies, complete to a (corrected) B magnitude of m_B^o=11.36. Of these, 30 have enough X-ray spectral counts to allow temperature determinations. We find that the temperatures...
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Context 1
... the 30 galaxies which have enough counts to allow accurate temperature determinations, Fig. 1 shows a logarithmic plot of their temperatures kT against σ, the central line-of-sight stellar velocity dispersions within the galaxies (from Faber et al. 1989or Dressler, Faber & Burstein 1991. Characteristics of the best fit linear regression to these data are shown in the first line of Table 2. We found that three galaxies (M32, NGC 1052 and NGC 2768) have temperatures of ∼ 3 − 4 keV, which are much greater than those of other galaxies with similar velocity dispersions. ...
Context 2
... those 27 galaxies with enough counts for elemental abundances to be constrained, we find that the measured abundances (driven by ∼1 keV Fe L emission in ROSAT PSPC spectra) are correlated with the gas temperatures: hotter gas tends to have higher abundances (see Fig. 2). Line 3 of Table 2 shows the regression results for all the data. When we exclude M32 and NGC 1052 from the regression (for being hot point sources, rather than diffuse gas), we find the abundance A ∝ T 2.44±0.69 ...
Context 3
... we exclude M32 and NGC 1052 from the regression (for being hot point sources, rather than diffuse gas), we find the abundance A ∝ T 2.44±0.69 (see line 4 of Table 2), with a dispersion of 0.48 dex in A. This latter correlation is shown as a dotted line in Fig. 2 (where M32 and NGC 1052 are also indicated). We have checked our abundances against the several published ASCA values and find that in most cases they agree within the 90% confidence level and in all cases they agree within the 99% confidence level. ...
Context 4
... PSPC temperatures are also consistent with the ASCA results. We find no correlation between our measured abundances and the stellar abundances of the host galaxies, as inferred from Mg 2 indices (7S) (see lines 5-6 of Table 2); this is consistent with the ASCA results of Loewenstein et al. (1994) and Mushotzky et al. (1994). ...
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Citations
... The phenomenon could be explained by the inclusion of a halo of additional matter throughout the galaxy. Further evidence emerged through the observation of elliptical galaxies [154] and through gravitational lensing [155,156]. Since then, compelling evidence [157][158][159] has been established for the existence of dark matter, and the quest to identify it has become one of the foremost goals of particle physics. ...
Composite Higgs models are a branch of Beyond the Standard Model theories which seek to address the hierarchy problem inherent to the current formulation of the Standard Model. In this thesis, we discuss and implement extensions to the scalar sector of the Standard Model, focusing on models of compositeness and their associated phenomenology. A key area of interest is then the appearance of compositeness at current and future colliders, which can be used to motivate the choice of the new era of experimental programs. To that end, this work details the construction of a number of effective models which are testable at colliders, and which are linked as extensions to the scalar sector. We include a comparison of twelve minimal composite Higgs modes featuring an underlying fermionic completion, and discuss ubiquitous features expected across all such models, including a light pseudo-scalar, which is shown to be reachable at future lepton colliders with the help of machine learning techniques. The study also reveals the consideration of bottom quarks in fermion-loops coupling the light scalar to SM states to be non-negligible. Phenomenology at future lepton colliders is extended through a study of the most minimal composite Higgs model of this nature, SU(4)/Sp(4), where we outline a potential search for the heavy pseudo-Nambu Goldstone boson ÷, considering both fermiophobic and fermiophilic couplings. While composite Higgs models seek primarily to address the separation of the electroweak and Planck energy scales, some such models may also produce dark matter candidates. We conclude this work with an investigation into heavy dark matter which couples to the top-sector of the Standard Model via a t-channel interaction, situating it within a composite Higgs model through its interaction with a heavy fermionic mediator and a top partner. Finally, the visibility of the model at colliders and astrophysical experiments is examined.
... In Figure 1 we show the observed dependence of the coronal gas temperature as a function of galaxy velocity dispersion for over-massive and under-massive black hole galaxies. The overall trend, as previously reported, follows a relation of roughly Tgas ∼ σ 1.5 (see, e.g., Davis & White 1996). In addition, the observed Tgas values for both over-massive and under-massive black hole galaxies are higher than expected from virial arguments, indicating that additional mechanisms contribute to heating the gas (Davis & White 1996;Goulding et al. 2016). ...
... The overall trend, as previously reported, follows a relation of roughly Tgas ∼ σ 1.5 (see, e.g., Davis & White 1996). In addition, the observed Tgas values for both over-massive and under-massive black hole galaxies are higher than expected from virial arguments, indicating that additional mechanisms contribute to heating the gas (Davis & White 1996;Goulding et al. 2016). ...
Observationally, constraining the baryonic cycle within massive galaxies has proven to be quite difficult. In particular, the role of black hole feedback in regulating star formation, a key process in our theoretical understanding of galaxy formation, remains highly debated. We present here observational evidence showing that, at fixed stellar velocity dispersion, the temperature of the hot gas is higher for those galaxies hosting more massive black holes in their centers. Analyzed in the context of well-established scaling relations, particularly the mass-size plane, the relation between the mass of the black hole and the temperature of the hot gas around massive galaxies provides further observational support to the idea that baryonic processes within massive galaxies are regulated by the combined effects of the galaxy halo virial temperature and black hole feedback, in agreement with the expectations from the EAGLE cosmological numerical simulation.
... The existence of dark matter (DM) has, since the its early days [1], been established through a wide range of detection techniques, such as galactic velocity curves [2][3][4][5], gravitational lensing [6], and its effects on Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB) [7]. However the interactions of DM outside of its gravitational influence remain elusive, despite concerted efforts to measure its scattering in terrestrial targets (direct detection), its annihilation or decay products in the galaxy or beyond (indirect detection), or through its direct production in colliders [8]. ...
We have considered a model of Dark Minimal Flavour Violation (DMFV), in which a triplet of dark matter particles couple to right-handed up-type quarks via a heavy colour-charged scalar mediator. By studying a large spectrum of possible constraints, and assessing the entire parameter space using a Markov Chain Monte Carlo (MCMC), we can place strong restrictions on the allowed parameter space for dark matter models of this type.
... A very low abundance of 0.1-0.2 was reported in the early phase (Loewenstein et al., 1994), but the accuracy was not high. The diffuse Xray emission in NGC 720 was studied previously with ROSAT and ASCA ( (Buote & Canizares 1994), 1996 and is studied in detail with Chandra in a separate paper (Buote et al., 2002). ...
... These data include two models APEC in two version 1.3.1 for data comparison and my data in new version APEC 3.0.2, we can see about 0.2 or 0.4 differ in data but, in finally all results in this work can be observe these values is near from the abundance values of temperature of (Davis & White 1996), which calculate the value of temperature for abundance at 0.5 keV by using ROSAT satellite. ...
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... For example, the gas to stellar mass fraction in rich clusters is typically greater than five (David et al. 1990) (36). Furthermore, x-ray emitting gas cannot originate through stellar kinematics, as the temperature is substantially hotter (Davis et al. 1996) (38). Instead, the ICM of clusters appears to be of primordial origin, i.e. before the formation of galaxies (David et al. 1991) (37). ...
... This is consistent with recent results demonstrating the mass to light ratio increases with ICM temperature (David et al. 1990) (36), where a systematic variation in early-type IMFs is observed as a function of (Cappellari et al. 2012) (23). The dependency of ICM temperature and cluster properties also extends to stellar dispersion, galaxy dispersion, x-ray luminosity and Mg Fe ratios (Davis et al. 1996;Richard 1998;Ortiz-Gil et al. 2004;Conroy et al. 2012) (38; 161; 149; 28). Further observations have shown that low mass stars dominate stellar distributions of larger ETGs; i.e. varieties represent over of the total population (van Dokkum 2010) (194). ...
Substantial evidence of a global gravitational potential is discussed including galaxy counts, angular size-redshift relations, SNIa and large-scale B-mode polarization within the cosmic background radiation. Local morphological luminosity functions are derived from several surveys and transformed to the BRIHK-bands through color-magnitude relations. These precise luminosity functions are applied to determine the necessary evolution for LCDM and universe with global gravitational potential. Galaxy counts and redshift distributions are found to be in agreement with the later up to 0.25z, where the existence of a local hole has been recently proposed at optical and near infrared wavelengths. Several angular diameter-redshift tests are provided with models of evolution to confirm the galaxy results. Large-scale B-mode polarization of the CMB further provides a 3.5 sigma detection using WMAP three year polarization data, with the center of a cosmological-scale potential in the direction of (8.1°±10.1°,4.9°±11.0°).
We summarize and reanalyze observations bearing upon missing galactic baryons, where we propose a consistent picture for halo gas in L >~ L* galaxies. The hot X-ray emitting halos are detected to 50-70 kpc, where typically, M_hot(<50 kpc) ~ 5E9 Msun, and with density n \propto r^-3/2. When extrapolated to R200, the gas mass is comparable to the stellar mass, but about half of the baryons are still missing from the hot phase. If extrapolated to 1.9-3 R200, the baryon to dark matter ratio approaches the cosmic value. Significantly flatter density profiles are unlikely for R < 50 kpc and they are disfavored but not ruled out for R > 50 kpc. For the Milky Way, the hot halo metallicity lies in the range 0.3-1 solar for R < 50 kpc. Planck measurements of the thermal Sunyaev-Zeldovich effect toward stacked luminous galaxies (primarily early-type) indicate that most of their baryons are hot, near the virial temperature, and extend beyond R200. This stacked SZ signal is nearly an order of magnitude larger than that inferred from the X-ray observations of individual (mostly spiral) galaxies with M_* > 10^11.3 Msun. This difference suggests that the hot halo properties are distinct for early and late type galaxies, possibly due to different evolutionary histories. For the cooler gas detected in UV absorption line studies, we argue that there are two absorption populations: extended halos; and disks extending to ~50 kpc, containing most of this gas, and with masses a few times lower than the stellar masses. Such extended disks are also seen in 21 cm HI observations and in simulations.
The galactic gaseous halo is a gas reservoir for the interstellar medium in the galaxy disk, supplying materials for star formation. We developed a gaseous halo model connecting the galaxy disk and the gaseous halo by assuming the star formation rate on the disk is balanced by the radiative cooling rate of the gaseous halo, including stellar feedback. In addition to a single-temperature gaseous halo in collisional ionization equilibrium, we also consider the photoionization effect and a steady-state cooling model. Photoionization is important for modifying the ion distribution in low-mass galaxies and outskirts of massive galaxies due to the low densities. The multi-phase cooling model dominates the region within the cooling radius, where t_cooling=t_Hubble. Our model reproduces most of the observed high ionization state ions for a wide range of galaxy masses (i.e., OVI, OVII, NeVIII, MgX, and OVIII). We find that the OVI column density has a narrow range around ~10^14 cm^-2 for halo masses from M_star ~ 3 * 10^10 Msun to 6*10^12 Msun, which is consistent with some but not all observational studies. For galaxies with halo masses <~ 3 * 10^11 Msun, photoionization produces most of the OVI, while for more massive galaxies, the OVI is from the medium that is cooling from higher temperatures. Fitting the Galactic (Milky-Way) OVII and OVIII suggests a gaseous halo model where the metallicity is ~0.55 Zsun and the gaseous halo has a maximum temperature of ~ 1.9 * 10^6 K. This gaseous halo model does not close the census of baryonic material within R200.
Studies of the physical properties of local elliptical galaxies (e.g., gas temperatures, halo masses, stellar kinematics) are shedding new light on galaxy formation. Here we present the hot X-ray gas properties of 33 early-type systems within the MASSIVE galaxy survey sample that have archival Chandra X-ray observations. Through careful X-ray spectral modeling, we derive X-ray luminosities (L_X) and plasma temperatures (T_gas) for the diffuse gas components in these galaxies. We combine the MASSIVE sample with 41 galaxies from the ATLAS^3D survey to investigate the X-ray and optical properties of a statistically significant sample of nearby early-type galaxies across a wide-range of environments. We deduce that all early-type galaxies (independent of galaxy mass and rotational support) follow a universal scaling law such that L_X~T_gas^4.5. When X-ray measurements are performed consistently in apertures set by the galaxy stellar content, the wide-scale environment does not contribute to the intrinsic scatter (~0.5dex) within the scaling relation. We further demonstrate that the scatter in L_X around both K-band luminosity (L_K) and the galaxy stellar velocity dispersion is primarily driven by T_gas, with no clear trends with halo mass, radio power, or angular momentum of the stars. It is not trivial to tie the origin of the gas directly to either the stellar mass or the galaxy potential. Indeed, our data require a steeper relation between L_X, L_K, and sigma_e than predicted by standard mass-loss models. Finally, we find a statistically significant correlation between sigma_e and T_gas, suggesting that T_gas is set by the galaxy potential inside the optical effective radius. We conclude that within the inner-most 10-30kpc region, early-types maintain pressure-supported hot gas, with a minimum T_gas set by the virial temperature, but the majority show evidence for some additional heating.
M32 hosts a 2.5×106 Msolar central black
hole, but signs of nuclear activity in this galaxy have long eluded
detection. We report the first conclusive detection of the nucleus of
M32 in X-rays, based on high-resolution, sensitive observations made
with Chandra. The 2-10 keV luminosity is merely
9.4×1035 ergs s-1, ~3×10-9
times the Eddington luminosity of the black hole. Weak diffuse emission,
consistent with thermal gas at a temperature of 0.37 keV, is seen in an
annular region ~100 pc from the center. We also present a deep,
moderately high-resolution (0.9") radio continuum observation obtained
with the Very Large Array, which places a tight upper bound on the
nuclear radio power at 8.4 GHz. We combine these new measurements with
upper limits at other wavelengths to discuss implications for the nature
of accretion onto the central black hole.
We performed five pointing observations with Suzaku
to search for hot gases associated with the junctions of galaxy filaments where no significant diffuse X-ray sources were previously detected. We discovered X-ray sources successfully in all five regions including merging groups of galaxies, Suzaku J0957+2610 and Suzaku J1134+2105, and analyzed two bright sources in each field. Spectral analysis indicates that three sources originate from X-ray diffuse halos associated with optically bright galaxies or groups of galaxies with kT ~ 0.6-0.8 keV. The three other sources are possibly group- and cluster-scale X-ray halos with temperatures of ~1 keV and ~4 keV, respectively while the others are compact object origins such as active galactic nuclei. All of the three observed intracluster media within the junctions of the galaxy filaments previously found are involved in ongoing mergers. Thus, we demonstrate that deep X-ray observations at the filament junctions identified by galaxy surveys are a powerful means to explore previously undetected growing halos in a hierarchical structure.
