The properties of galaxies are intricately linked to the characteristics of their host dark-matter haloes. We use a suite of controlled simulations of isolated galaxies to quantify how halo spin, concentration, inner density profile, and baryon fraction regulate galaxy sizes, at fixed halo mass of $M_{\rm{vir}}=10^{11} M_\odot$. We generate initial conditions of haloes and inhabitant spherical gas distributions in equilibrium, on a parameter grid spanned by these four halo parameters, and evolve the systems with the $\texttt{GIZMO}$ code and the $\texttt{FIRE-3}$ physics. The resulting half-mass radii of stars and cold baryons depend systematically on halo structure and baryon content: galaxy size increases with halo spin, decreases with halo concentration, is weakly sensitive to the inner density slope except in highly cuspy haloes, and is strongly suppressed at high baryon fractions. We evaluate the relative importance of the halo parameters on galaxy size using different metrics including the quadratic response-surface method and random-forest regression, and consistently find halo concentration to be the most informative predictor of size. The baryon fraction shows a subtle, non-monotonic impact on size, by modulating how galaxy size depends on halo spin. Our results clarify which secondary parameters of host dark-matter haloes dominate the scatter in galaxy sizes at the massive-dwarf mass scale.
Halo mass, star formation, and morphology in galaxies: A morphology-dependent connection between halo environment and star formation activity
Instituto de Fisica de Cantabria (CSIC-Universidad de Cantabria)(坎塔布里亚物理研究所(西班牙科学研究中心-坎塔布里亚大学));University of Southampton(南安普顿大学);National Observatory of Athens(雅典国家天文台)
The AGORA High-resolution Galaxy Simulations Comparison Project. XI: Solving the Non-Spherical Morphology and Evolution of Dark Matter Halos with Haskap Pie
University of Illinois Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);Lund University(隆德大学);Seoul National University(首尔大学);Osaka University(大阪大学)
Connection between galaxy morphology and dark-matter halo structure II: predicting disk structure from dark-matter halo properties
Peking University(北京大学);Kavli Institute for Astronomy and Astrophysics, Peking University(北京大学科维理天文与天体物理研究所);Department of Astronomy, University of Massachusetts, Amherst(马萨诸塞大学阿默斯特分校天文学系);Carnegie Observatories(卡内基观测站);TAPIR, California Institute of Technology(加州理工学院 TAPIR);Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University(耶路撒冷希伯来大学拉卡物理学院天体物理学与行星科学中心)
We use the TNG100 simulation of the IllustrisTNG project to investigate the stellar specific angular momenta ($j_{\ast}$) of $\sim$12,000 central galaxies at $z=0$ in a full cosmological context, with stellar masses ($M_{\ast}$) ranging from $10^{9}$ to $10^{12} \, {\rm M}_{\odot}$. We find that the $j_{\ast}$-$M_{\ast}$ relations for early-type and late-type galaxies in IllustrisTNG are in good overall agreement with observations, and that these galaxy types typically `retain' $\sim$10-20 and $\sim$50-60 per cent of their host haloes' specific angular momenta, respectively, with some dependen…
In this paper, we report a robust measurement of the morphology, color and galaxy size dependences of the stellar-halo mass relation (SHMR) at the high mass end ($10^{11.3}{\rm M_{\odot}}<M_{\star}<10^{11.7}{\rm M_{\odot}}$) at redshift $z_s\sim0.6$ (Throughout the paper, we use $z_s$ for redshift, $z$ for the z-band magnitude.). Applying our method, Photometric objects Around Cosmic webs (PAC), developed in a previous work to CMASS and HSC-SSP observations, we measure the excess surface density ($\bar{n}_2w_p(r_p)$) of satellites around massive central galaxies with different morphologies ind…
We present measurements of the morphology of star-forming gas in galaxies from the EAGLE simulations, and its alignment relative to stars and dark matter (DM). Imaging of such gas in the radio continuum enables weak lensing experiments that complement traditional optical approaches. Star-forming gas is typically more flattened than its associated stars and DM, particularly for present-day subhaloes of total mass $\sim$$10^{ 12-12.5} \mathrm{M_{ \odot}}$, which preferentially host star-forming galaxies with rotationally-supported stellar discs. Such systems have oblate, spheroidal star-forming …
Observations have shown that spatially extended "TeV halos" are a common (and potentially generic) feature surrounding young and middle-aged pulsars. However, their morphology is not understood. They are larger than the "compact" region where the stellar remnant dominates the properties of the interstellar medium, but smaller than expected in models of cosmic-ray diffusion through the standard interstellar medium. Several explanations have been proposed, but all have shortcomings. Here, we revisit a class of models where the cosmic-ray gradient produced by the central source induces a streamin…
We investigate the dependence of the local galaxy stellar-to-halo mass relation (SHMR) on galaxy morphology. We use data from the Sloan Digital Sky Survey DR7 with morphological classifications from Galaxy Zoo, and compare with the EAGLE cosmological simulation. At fixed halo mass in the mass range $10^{11.7}-10^{12.9}M_{\odot}$, the median stellar masses of SDSS disc galaxies are up to a factor of 1.4 higher than the median masses of their elliptical counterparts. However, when we switch from the stellar masses from Kauffmann et al. to those calculated by Chang et al. or Brinchmann et al., th…
Constraining dark matter halo profiles and galaxy formation models using spiral arm morphology. II. Dark and stellar mass concentrations for 13 nearby face-on galaxies
In this work we aim at investigating the effects of baryons on the dark matter (DM) haloes structure, focusing on the correlation between the presence and importance of stellar discs and the halo shapes. We study the properties of a subsample of DM haloes from Fenix and EAGLE cosmological simulations. We inspect the central regions of haloes in the mass range [10.9 - 992.3] x 10^{10} Msun at z=0, comparing the hydrodynamic runs and their dark matter only (DMo) counterparts. Our results indicate that baryons have a significant impact on the shape of the inner halo, mainly within ~ 20 percent of…
We use Hubble space telescope data of 45 nearby star-forming galaxies to investigate properties of Lyman-alpha (Ly$α$) halos, Ly$α$ morphology, and the star-forming characteristics of galaxies. We study how the morphology of Ly$α$ emission is related to other Ly$α$ observables. Furthermore, we study the interdependencies of Ly$α$ morphological quantities. We studied the spatial extent of Ly$α$ using surface brightness profiles in i) using circular apertures and ii) within faint Ly$α$ isophotes. We measured the average intensity and the size of the regions with a high star formation rate densit…
We derive the stellar-to-halo mass relation (SHMR), namely $f_\star\propto M_\star/M_{\rm h}$ versus $M_\star$ and $M_{\rm h}$, for early-type galaxies from their near-IR luminosities (for $M_\star$) and the position-velocity distributions of their globular cluster systems (for $M_{\rm h}$). Our individual estimates of $M_{\rm h}$ are based on fitting a dynamical model with a distribution function expressed in terms of action-angle variables and imposing a prior on $M_{\rm h}$ from the concentration-mass relation in the standard $Λ$CDM cosmology. We find that the SHMR for early-type galaxies d…
We perform cosmological zoom-in simulations of $19$ relaxed cluster-mass haloes with the inclusion of adiabatic gas in the cold dark matter (CDM) and self-interacting dark matter (SIDM) models. These clusters are selected as dynamically relaxed clusters from a parent simulation with $M_{\rm 200} \simeq 1\operatorname{-}3\times 10^{15}\,{\rm M}_{\odot}$. Both the dark matter and the intracluster gas distributions in SIDM appear more spherical than their CDM counterparts. Mock X-ray images are generated based on the simulations and are compared to the real X-ray images of $84$ relaxed clusters s…
Small- and Large-Scale Galactic Conformity in SDSS DR7
星系整合是指星系性质在距离上表现出比预期的更多的相关性,如果这些性质只依赖于晕质量。我们进行了全面的研究一致性在低红移使用星系群目录从SDSS DR 7光谱样本。我们研究了中央星系和它们的卫星星系(1-晕)之间的相关性,以及中央星系在单独的晕(2-晕)之间的相关性。我们使用淬火分数和显着的关联函数(MCF),探测符合三个星系的属性,$(g-r)$颜色,特定的恒星形成率(sSFR),和形态。我们评估了一套模拟星系目录,没有内置的一致性,但包含相同的组发现和质量分配错误的真实数据的一致性信号的统计意义。在1-晕一致性的情况下,淬火馏分在所有组质量显示出强信号。然而,这些信号在模拟星表中同样强烈,表明一致性信号是虚假的,可能完全是由群体发现系统学引起的,这对以前的1-halo一致性检测提出了质疑。MCF揭示了大量群体内的径向分离的显著检测,但没有一致性的证据。在2-卤素一致性的情况下,淬火馏分显示没有显着的证据一致性的颜色或sSFR一旦与模拟目录相比,但使用形态学的明确信号。相比之下,MCF揭示了低质量组和$0.8-4\ h^{-1}\textrm{Mpc}$标度中所有三种性质的小但高度显著的信号,可能代表2-晕一致性的首次稳健检测。
We search for detectable signatures of f(R) gravity and its chameleon screening mechanism in the baryonic and dark matter (DM) properties of simulated void galaxies. The enhancement of the gravitational acceleration can have a meaningful impact on the scaling relations as well as on the halo morphology. The galaxy rotational velocity field (calculated with the velocity of the gas disc and the acceleration fields) deviates from the typical values of the Tully-Fisher Relation (TFR) in GR. For a given stellar mass, f(R) gravity tends to produce greater maximum velocities. On the other hand, the m…
Disentangling the Morphology of Palomar~5: Effects of the Bar, Spiral Arms, LMC, and Halo Flattening
School of Physics and Astronomy, Sun Yat-sen University(中山大学物理学院);CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area(中国空间站科学中心粤港澳大湾区分中心);School of Astronomy and Space Science, University of Chinese Academy of Sciences(中国科学院大学天文与空间科学学院);National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台);University of Surrey(萨里大学)
This is the first paper in a series of studies of the Coma cluster using the SRG/eROSITA X-ray data obtained in course of the Calibration and Performance Verification observations. The data cover $\sim3^\circ\times 3^\circ$ area around the cluster with a typical exposure time of more than 20 ks. The stability of the instrumental background and operation of the SRG Observatory in the scanning mode provided us with an excellent data set for studies of the diffuse emission up to a distance of $\sim 1.5R_{200}$ from the Coma center. In this study, we discuss the rich morphology revealed by the X-r…
Dark Matter Annihilation Feedback in Cosmological Simulations II: The Influence on Gas and Halo Structure
我们提出了新的宇宙学流体动力学模拟,将暗物质湮灭反馈(DMAF),从而从暗物质粒子通过衰变通道,如光子或正电子-电子对湮灭释放的能量提供额外的加热源本地重子材料。对于湮没率相当于WIMP类粒子,我们发现DMAF的关键影响是抑制气体吸积到晕。这种减少的气体吸积在晕的寿命早期的结果减少气体分数在较小的晕,和延迟的晕形成时间的较大的结构,这表明DMAF可能会影响星系中的恒星年龄分布,和矮星的形态。对于$m_χ\sim10$ ~MeV的暗物质粒子质量,在$z=0$处存在$\sim10^{13}$ M $_{\odot}$的“临界晕质量”,低于该临界晕质量与$Λ$ CDM相比存在很大差异,例如晕结构丰度降低高达25%,在质量为$\sim10^{12}$ M $_{\odot}$的晕圈内,气体含量减少50%,中心气体密度降低到10%,但在较小的晕圈中效果增加。较高的暗物质粒子质量模型有一个较小的“临界晕质量”。对于$m_χ\sim100$ ~MeV模型,我们发现在$\sim10^{12}$ M $_\odot$和$m_χ\gtrsim 1$ ~GeV模型的晕质量以下开始出现差异,这个质量尺度低于我们模拟的分辨率,尽管我们仍然观察到矮星系形态的变化。
We investigate the morphology of the stellar distribution in a sample of Milky Way (MW) like galaxies in the TNG50 simulation. Using a local in shell iterative method (LSIM) as the main approach, we explicitly show evidence of twisting (in about 52% of halos) and stretching (in 48% of them) in the real space. This is matched with the re-orientation observed in the eigenvectors of the inertia tensor and gives us a clear picture of having a re-oriented stellar distribution. We make a comparison between the shape profile of dark matter (DM) halo and stellar distribution and quite remarkably see t…