Galaxy Zoo: the dependence of the star formation-stellar mass relation on spiral disk morphology
Kyle W. Willett, Kevin Schawinski, Brooke D. Simmons, Karen L. Masters, Ramin A. Skibba, Sugata Kaviraj, Thomas Melvin, O. Ivy Wong, Robert C. Nichol, Edmond Ch… 展开作者
Kyle W. Willett, Kevin Schawinski, Brooke D. Simmons, Karen L. Masters, Ramin A. Skibba, Sugata Kaviraj, Thomas Melvin, O. Ivy Wong, Robert C. Nichol, Edmond Cheung, Chris J. Lintott, Lucy Fortson
We measure the stellar mass-star formation rate relation in star-forming disk galaxies at z<0.085, using Galaxy~Zoo morphologies to examine different populations of spirals as classified by their kiloparsec-scale structure. We examine the number of spiral arms, their relative pitch angle, and the presence of a galactic bar in the disk, and show that both the slope and dispersion of the M-SFR relation is constant when varying all the above parameters. We also show that mergers (both major and minor), which represent the strongest conditions for increases in star formation at a constant mass, only boost the SFR above the main relation by ~0.3 dex; this is significantly smaller than the increase seen in merging systems at z>1. Of the galaxies lying significantly above the M-SFR relation in the local Universe, more than 50% are mergers. We interpret this as evidence that the spiral arms, which are imperfect reflections of the galaxy's current gravitational potential, are either fully independent of the various quenching mechanisms or are completely overwhelmed by the combination of outflows and feedback. The arrangement of the star formation can be changed, but the system as a whole regulates itself even in the presence of strong dynamical forcing.
Understanding the effect spiral structure has on star formation properties of galaxies is important to completing our picture of spiral structure evolution. Previous studies have investigated connections between spiral arm properties with star formation, but the effect that the number of spiral arms has on this process is unclear. Here we use the Galaxy and Mass Assembly (GAMA) survey paired with the citizen science visual classifications from the Galaxy Zoo project to explore galaxies' spiral arm number and how it connects to the star formation process. We use the votes from the GAMA-KiDS Gal…
We use classifications provided by citizen scientists though Galaxy Zoo to investigate the correlation between bulge size and arm winding in spiral galaxies. Whilst the traditional spiral sequence is based on a combination of both measures, and is supposed to favour arm winding where disagreement exists, we demonstrate that, in modern usage, the spiral classifications Sa-Sd are predominantly based on bulge size, with no reference to spiral arms. Furthermore, in a volume limited sample of galaxies with both automated and visual measures of bulge prominence and spiral arm tightness, there is at …
The challenge of consistent identification of internal structure in galaxies - in particular disc galaxy components like spiral arms, bars, and bulges - has hindered our ability to study the physical impact of such structure across large samples. In this paper we present Galaxy Zoo: 3D (GZ: 3D) a crowdsourcing project built on the Zooniverse platform which we used to create spatial pixel (spaxel) maps that identify galaxy centres, foreground stars, galactic bars and spiral arms for 29831 galaxies which were potential targets of the MaNGA survey (Mapping Nearby Galaxies at Apache Point Observat…
Spiral structure is ubiquitous in the Universe, and the pitch angle of arms in spiral galaxies provide an important observable in efforts to discriminate between different mechanisms of spiral arm formation and evolution. In this paper, we present a hierarchical Bayesian approach to galaxy pitch angle determination, using spiral arm data obtained through the Galaxy Builder citizen science project. We present a new approach to deal with the large variations in pitch angle between different arms in a single galaxy, which obtains full posterior distributions on parameters. We make use of our pitc…
We present gas and stellar kinematics of a high-resolution zoom-in cosmological chemodynamical simulation, which fortuitously captures the formation and evolution of a star-forming barred spiral galaxy, from redshift $z\sim3$ to $z\sim2$ at the peak of the cosmic star formation rate. The galaxy disc grows by accreting gas and substructures from the environment. The spiral pattern becomes fully organised when the gas settles from a thick (with vertical dispersion $σ_{v} >$ 50 km/s) to a thin ($σ_{v} \sim 25$ km/s) disc component in less than 1 Gyr. Our simulated disc galaxy also has a central X…
We describe the Gems of the Galaxy Zoos (Zoo Gems) project, a gap-filler project using short windows in the Hubble Space Telescope's schedule. As with previous snapshot programs, targets are taken from a pool based on position; we combine objects selected by volunteers in both the Galaxy Zoo and Radio Galaxy Zoo citizen-science projects. Zoo Gems uses exposures with the Advanced Camera for Surveys (ACS) to address a broad range of topics in galaxy morphology, interstellar-medium content, host galaxies of active galactic nuclei, and galaxy evolution. Science cases include studying galaxy intera…
Multi-component modelling of galaxies is a valuable tool in the effort to quantitatively understand galaxy evolution, yet the use of the technique is plagued by issues of convergence, model selection and parameter degeneracies. These issues limit its application over large samples to the simplest models, with complex models being applied only to very small samples. We attempt to resolve this dilemma of "quantity or quality" by developing a novel framework, built inside the Zooniverse citizen science platform, to enable the crowdsourcing of model creation for Sloan Digitial Sky Survey galaxies.…
We examine the azimuthal variations in gas-phase metallicity profiles in simulated Milky Way mass disk galaxies from the Feedback in Realistic Environments (FIRE-2) cosmological zoom-in simulation suite, which includes a sub-grid turbulent metal mixing model. We produce spatially resolved maps of the disks at $z \approx 0$ with pixel sizes ranging from 250 to 750~pc, analogous to modern integral field unit (IFU) galaxy surveys, mapping the gas-phase metallicities in both the cold & dense gas and the ionized gas correlated with HII regions. We report that the spiral arms alternate in a pattern …
The distribution of the spin directions of spiral galaxies in the Sloan Digital Sky Survey has been a topic of debate in the past two decades, with conflicting conclusions reported even in cases where the same data was used. Here we follow one of the previous experiments by applying the SpArcFiRe algorithm to annotate the spin directions in original dataset of Galaxy Zoo 1. The annotation of the galaxy spin directions is done after a first step of selecting the spiral galaxies in three different manners: manual analysis by Galaxy Zoo classifications, by a model-driven computer analysis, and wi…
University of Oxford（牛津大学）；University of Nottingham（诺丁汉大学）；University of Minnesota（明尼苏达大学）；European Space Agency（欧洲空间局）；Haverford College（哈弗福德学院）；University of Portsmouth（朴茨茅斯大学）
We use Bayesian convolutional neural networks and a novel generative model of Galaxy Zoo volunteer responses to infer posteriors for the visual morphology of galaxies. Bayesian CNN can learn from galaxy images with uncertain labels and then, for previously unlabelled galaxies, predict the probability of each possible label. Our posteriors are well-calibrated (e.g. for predicting bars, we achieve coverage errors of 11.8% within a vote fraction deviation of 0.2) and hence are reliable for practical use. Further, using our posteriors, we apply the active learning strategy BALD to request voluntee…
Dust lanes bisect the plane of a typical edge-on spiral galaxy as a dark optical absorption feature. Their appearance is linked to the gravitational stability of spiral disks; the fraction of edge-on galaxies that displays a dust lane is a direct indicator of the typical vertical balance between gravity and turbulence; a balance struck between the energy input from star-formation and the gravitational pull into the plane of the disk. Based on morphological classifications by the Galaxy~Zoo project on the Kilo-Degree Survey (KiDS) imaging data in the Galaxy and Mass Assembly (GAMA) fields, we e…
Spiral Morphology and Radial Migration: Kinematically heating, cooling, and cold
University of Arizona（亚利桑那大学）；Bryn Mawr College（布林莫尔学院）；University of California, Merced（加州大学默塞德分校）；Haverford College（哈弗福德学院）；Johns Hopkins University（约翰斯·霍普金斯大学）
Spiral galaxies have distinct internal structures including a stellar bulge, disk and spiral arms. It is unknown when in cosmic history these structures formed. We analyze observations of BRI 1335-0417, an intensely star-forming galaxy in the distant Universe, at redshift 4.41. The [C II] gas kinematics show a steep velocity rise near the galaxy center and have a two-armed spiral morphology that extends from about 2 to 5 kiloparsecs in radius. We interpret these features as due to a central compact structure, such as a bulge, a rotating gas disk and either spiral arms or tidal tails. These fea…
University of Oxford（牛津大学）；European Space Agency（欧洲空间局）；University of Portsmouth（朴茨茅斯大学）；University of Minnesota（明尼苏达大学）；University of Nottingham（诺丁汉大学）；Princeton University（普林斯顿大学）
We present Galaxy Zoo DECaLS: detailed visual morphological classifications for Dark Energy Camera Legacy Survey images of galaxies within the SDSS DR8 footprint. Deeper DECaLS images (r=23.6 vs. r=22.2 from SDSS) reveal spiral arms, weak bars, and tidal features not previously visible in SDSS imaging. To best exploit the greater depth of DECaLS images, volunteers select from a new set of answers designed to improve our sensitivity to mergers and bars. Galaxy Zoo volunteers provide 7.5 million individual classifications over 314,000 galaxies. 140,000 galaxies receive at least 30 classification…
For a sample of 4378 nearby spiral and S0 galaxies, Yu and Ho (2020) used Fourier analysis of Sloan Digital Sky Survey images to show that the strengths of the spiral arms and the pitch angles of the arms are inversely correlated with central concentration. In the current study, we search for trends in the Yu and Ho (2020) spiral arm parameters with environment and specific star formation rate (sSFR). When comparing galaxies with similar concentrations, we do not find a significant difference in the arm strengths or pitch angles of spiral galaxies in clusters compared to field galaxies. When d…
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
Dynamics and Morphology of the Milky Way Spiral Arms from the Metallicity Distribution and Radial Mixing
尽管径向迁移在盘星系中是一个普遍存在的过程，但它在恒星盘演化中的意义并不总是通过全球趋势反映出来。然而，还有其他关键的观测数据，如金属丰度分布函数（metallicity distribution function，简写为EAF），可能会在这个问题上有所启发。我们认为，螺旋线的形状不仅告诉我们恒星盘是否经历了径向迁移，而且它还包含了触发它的结构的重要线索。具体来说，螺旋线包含有关螺旋图案的动力学和形态的信息。为了限制螺旋参数，我们在模拟中加入了详细的化学标记;这使我们能够限制银河系螺旋臂的结构参数，以及限制化学演化模型朝向银河系圆盘中心的方法，在那里没有化学模型提供信息。我们还发现，太阳不太可能在其当前的银河系中心位置附近形成，因此将太阳视为太阳附近化学丰度的代表可能是不准确的。我们还表明，银河系的恒星盘，经过动态和化学演变为5 Gyr，保留80%的原始全球金属丰度梯度，尽管遭受了重要的加热和径向迁移，这意味着在一个给定的星系中存在的金属丰度梯度，并不能保证径向混合没有发挥作用，在其演变。
Deep Learning Segmentation of Spiral Arms and Bars for 600,000 Galaxies in DESI
University of Hertfordshire（赫特福德大学）；Dunlap Institute for Astronomy and Astrophysics, University of Toronto（多伦多大学邓普天体物理研究所）；Jodrell Bank Centre for Astrophysics, Department of Physics & Astronomy, University of Manchester（曼彻斯特大学物理与天文系乔德雷克天体物理学中心）；Department of Physics and Astronomy, Haverford College（哈弗福德学院物理与天文系）；Masaryk University（马萨里克大学）；Lancaster University（兰卡斯特大学）；The Open University（开放大学）
The Galaxy Zoo (GZ) project has provided quantitative visual morphologies for over a million galaxies, and has been part of a reinvigoration of interest in the morphologies of galaxies and what they reveal about galaxy evolution. Morphological information collected by GZ has shown itself to be a powerful tool for studying galaxy evolution, and GZ continues to collect classifications - currently serving imaging from DECaLS in its main site, and running a variety of related projects hosted by the Zooniverse; the citizen science platform which came out of the early success of GZ. I highlight some…
This study investigates the role of large-scale environments on the fraction of spiral galaxies at $z=$ 0.3-0.6 sliced to three redshift bins of $Δz=0.1$. Here, we sample 276220 massive galaxies in a limited stellar mass of $5\times10^{10}$ solar mass ($\sim M^\ast$) over 360 deg$^2$, as obtained from the Second Public Data Release of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). By combining projected two-dimensional density information (Shimakawa et al. 2021) and the CAMIRA cluster catalog (Oguri et al. 2018), we investigate the spiral fraction across large-scale overdensities an…
We analyze two-armed global spiral density wave modes generated by gravitational instability in razor-thin, non-viscous, self-gravitating protoplanetary disks to understand the dependence of spiral arm morphology (pitch angle $α$ and amplitude) on various disk conditions. The morphologies of the resulting spiral density wave modes closely resemble observations. Their pitch angles and pattern speeds are insensitive to the boundary conditions adopted. Gaussian disks exhibit more tightly wound spirals (smaller pitch angle) than power law disks under the same conditions. We find that at a fixed di…
Galaxies broadly fall into two categories: star-forming (blue) galaxies and quiescent (red) galaxies. In between, one finds the less populated ``green valley". Some of these galaxies are suspected to be in the process of ceasing their star-formation through a gradual exhaustion of gas supply or already dead and are experiencing a rejuvenation of star-formation through fuel injection. We use the Galaxy And Mass Assembly database and the Galaxy Zoo citizen science morphological estimates to compare the morphology of galaxies in the green valley against those in the red sequence and blue cloud. O…
In this letter we construct a large sample of early-type galaxies with measured gas-phase metallicities from the Sloan Digital Sky Survey and Galaxy Zoo in order to investigate the origin of the gas that fuels their residual star formation. We use this sample to show that star forming elliptical galaxies have a substantially different gas-phase metallicity distribution from spiral galaxies, with ~7.4% having a very low gas-phase metallicity for their mass. These systems typically have fewer metals in the gas phase than they do in their stellar photospheres, which strongly suggests that the mat…
We investigate one-halo galactic conformity (the tendency for satellite galaxies to mirror the properties of their central) in both star-formation and morphology using a sample of 8230 galaxies in 1266 groups with photometry and spectroscopy from the Sloan Digital Sky Survey, morphologies from Galaxy Zoo and group memberships as determined by Yang et al. This is the first paper to investigate galactic conformity in both star-formation and visual morphology properties separately. We find that the signal of galactic conformity is present at low significance in both star-formation and visual morp…
Active galactic nucleus activity in nearby disk galaxies: The roles of bar strength and spiral arm morphology
Yerevan State University（埃里温国立大学）；Institute of Physics, Yerevan State University（埃里温国立大学物理研究所）；Alikhanian National Science Laboratory（阿利哈尼扬国家科学实验室）；Center for Cosmology and Astrophysics, Alikhanian National Science Laboratory（阿利哈尼扬国家科学宇宙学与天体物理学中心）；Universidade do Porto（波尔图大学）；Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto（波尔图大学空间与天体物理研究所）；Faculdade de Ciências, Universidade do Porto（波尔图大学理学院）
We analyse the distribution of Mira variable stars in the central region of the Milky Way. We find that with increasing period, i.e. decreasing age, the Miras shift towards negative Galactic longitudes $\ell$. Comparing to a cosmological zoom simulation of a barred galaxy, we find that this shift with age can be explained by an age-morphology dependence of the boxy peanut/bulge. Owing to a combination of projection effects and the limitation of the range of Galactic longitudes, the near hump at $\ell>0$ is more truncated for younger populations, and the far hump at $\ell<0$ dominates the obser…
Here Be SDRAGNs - Spiral Galaxies Hosting Large Double Radio Sources
Radio Galaxy Zoo（无线电星系动物园）；University of Alabama（阿拉巴马大学）；Stanford University（斯坦福大学）；CSIRO Space & Astronomy（澳大利亚联邦科学与工业研究组织空间与天文部）；University of Western Australia（西澳大学）；Thüringer Landessternwarte（图林根州立天文台）；Universidad de Guanajuato（瓜纳华托大学）；Australian National University（澳大利亚国立大学）；Special Astrophysical Observatory（特殊天体物理观测站）
The classification of galaxy morphology plays a crucial role in understanding galaxy formation and evolution. Traditionally, this process is done manually. The emergence of deep learning techniques has given room for the automation of this process. As such, this paper offers a comparison of deep learning architectures to determine which is best suited for optical galaxy morphology classification. Adapting the model training method proposed by Walmsley et al in 2021, the Zoobot Python library is used to train models to predict Galaxy Zoo DECaLS decision tree responses, made by volunteers, using…
We investigate the role of environment on radio galaxy properties by constructing a sample of large ($\gtrsim100$~kpc), nearby ($z<0.3$) radio sources identified as part of the Radio Galaxy Zoo citizen science project. Our sample consists of 16 Fanaroff-Riley Type II (FR-II) sources, 6 FR-I sources, and one source with a hybrid morphology. FR-I sources appear to be hosted by more massive galaxies, consistent with previous studies. In the FR-II sample, we compare the degree of asymmetry in radio lobe properties to asymmetry in the radio source environment, quantified through optical galaxy clus…
From Galaxy Zoo DECaLS to BASS/MzLS: detailed galaxy morphology classification with unsupervised domain adaption
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；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）；Shanghai Key Lab for Astrophysics, Shanghai Normal University（上海师范大学上海市天体物理重点实验室）；Centre for Astrophysics Research, University of Hertfordshire（赫特福德大学天体物理研究中心）
Machine Learning for Galaxy Morphology Classification
University of Malta（马耳他大学）
在这项工作中，决策树学习算法和模糊推理系统适用于星系形态分类。特别是，CART，C4.5，随机森林和模糊逻辑算法进行了研究和可靠的分类器的开发，以区分螺旋星系，椭圆星系或恒星/未知的星系物体。训练和测试数据集的形态信息来自Galaxy Zoo项目，而相应的光度和光谱参数则从SDSS DR 7目录下载。
