The Luminosity, Mass, and Age Distributions of Compact Star Clusters in M83 Based on HST/WFC3 Observations
Rupali Chandar, Bradley C. Whitmore, Hwihyun Kim, Catherine Kaleida, Max Mutchler, Daniela Calzetti, Abhijit Saha, Robert O'Connell, Bruce Balick, Howard Bond, … 展开作者
Rupali Chandar, Bradley C. Whitmore, Hwihyun Kim, Catherine Kaleida, Max Mutchler, Daniela Calzetti, Abhijit Saha, Robert O'Connell, Bruce Balick, Howard Bond, Marcella Carollo, Michael Disney, Michael A. Dopita, Jay A. Frogel, Donald Hall, Jon A. Holtzman, Randy A. Kimble, Patrick McCarthy, Francesco Paresce, Joe Silk, John Trauger, Alistair R. Walker, Rogier A. Windhorst, Erick Young
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36 pages, 13 figures, 1 table; accepted for publication in the Astrophysical Journal
The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL \propto L^{alpha}, with alpha = -2.04 +/- 0.08, down to M_V ~ -5.5. We test the sensitivity of the luminosity function to different selection techniques, filters, binning, and aperture correction determinations, and find that none of these contribute significantly to uncertainties in alpha. We estimate ages and masses for the clusters by comparing their measured UBVI,Halpha colors with predictions from single stellar population models. The age distribution of the clusters can be approximated by a power-law, dN/dt propto t^{gamma}, with gamma=-0.9 +/- 0.2, for M > few x 10^3 Msun and t < 4x10^8 yr. This indicates that clusters are disrupted quickly, with ~80-90% disrupted each decade in age over this time. The mass function of clusters over the same M-t range is a power law, dN/dM propto M^{beta}, with beta=-1.94 +/- 0.16, and does not have bends or show curvature at either high or low masses. Therefore, we do not find evidence for a physical upper mass limit, M_C, or for the earlier disruption of lower mass clusters when compared with higher mass clusters, i.e. mass-dependent disruption. We briefly discuss these implications for the formation and disruption of the clusters.
Euclid and the Roman Space Telescope (Roman) will soon use grism spectroscopy to detect millions of galaxies via H$α$ and [O III] $λ5007$ emission. To better constrain the expected galaxy counts from these instruments, we use a vetted sample of 4,239 emission-line galaxies from the 3D-HST survey to measure the H$α$ and [O III] $λ5007$ luminosity functions between $1.16<z<1.90$; this sample is $\sim 4$ times larger than previous studies at this redshift. We find very good agreement with previous measurements for H$α$, but for [O III], we predict a higher number of intermediate-luminosity galaxi…
We present measurements of the dependence of the clustering amplitude of galaxies on their star formation rate (SFR) and stellar mass ($M_*$) at $0.7 < z < 1.5$ to assess the extent to which environment affects these properties. While these relations are well determined in the local universe, they are much more poorly known at earlier times. For this analysis we make use of the near-IR HST WFC3 grism spectroscopic data in the five CANDELS fields obtained as part of the 3D-HST survey. We make projected 2-point correlation function measurements using $\sim$6,000 galaxies with accurate redshifts,…
We present the largest systematic, HST-based search to date for luminous $z\gtrsim8$ galaxy candidates using $\sim$1267 arcmin$^{2}$ of (pure-)parallel observations from a compilation of 288 random sightlines with ACS and WFC3 observations, derived from the SuperBoRG data set and together representing a factor $\sim1.12\times$ larger than existing space-based data sets. Using NIR color cuts and careful photo-$z$ analyses, we find 31 $z\gtrsim8$ galaxy candidates over 29 unique sightlines, and derive global galaxy properties such as UV magnitudes and continuum slopes, sizes, and rest-frame opti…
The abundance of bright galaxies at z>8 can provide key constraints on models of galaxy formation and evolution, as the predicted abundance varies greatly when different physical prescriptions for gas cooling and star formation are implemented. We present the results of a search for bright z=9-10 galaxies selected from pure-parallel Hubble Space Telescope imaging programs. We include 132 fields observed as part of the Brightest of Reionizing Galaxies survey, the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, and the WFC3 Infrared Spectroscopic Parallel survey. These observations c…
We here present the luminosity function (LF) of globular clusters (GCs) in five nearby spiral galaxies using the samples of GC candidates selected in Hubble Space Telescope mosaic images in F435W, F555W and F814W filters. Our search, which surpasses the fractional area covered by all previous searches in these galaxies, has resulted in the detection of 158 GC candidates in M81, 1123 in M101, 226 in NGC4258, 293 in M51 and 173 in NGC628. The LFs constructed from this dataset, after correcting for relatively small contamination from reddened young clusters, are log-normal in nature, which was hi…
An HST/WFPC2 survey of bright young clusters in M31. IV. Ages and mass estimates
【目标】本文介绍了利用哈勃空间望远镜（HST）上的广角行星照相机2（WFPC 2）对M31中可能的年轻大质量星团（YMC）进行成像巡天的主要结果。我们提出的图像和彩色星等图（CMD），我们所有的目标。{方法。}通过比较观测到的CMD和光度函数与理论模型，估算了团簇的红化、年龄和金属丰度。恒星质量的估计是通过与理论模型在对数（年龄）与绝对积分星等平面的比较。{结果。} 20个候选星团中有19个被证实是真正的星团。三个集群被发现不是很好的YMC候选人从新的集成光谱，实际上被发现是旧的，从他们的CMD。在剩下的16个星团中，14个星团的年龄在2500万年到28000万年之间，2个星团的年龄超过50000万年（下限）。通过纳入文献中其他10个YMC和HST测光，我们收集了25个年龄小于1 Gyr的星团样本，质量范围从0.6 x 10^4 M_sun到6 x 10^4 M_sun，平均约为3 x 10^4 M_sun。【结论】这里考虑的星团被证实有质量显着高于银河系疏散星团在相同的年龄范围。我们的分析表明，YMC在本星系群中所有最大的恒星形成星系中相对常见。
A long-standing problem when deriving the physical properties of stellar populations is the degeneracy between age, reddening, and metallicity. When a single metallicity is used for all star clusters in a galaxy, this degeneracy can result in $`$catastrophic$'$ errors for old globular clusters. Typically, approximately 10 - 20 % of all clusters detected in spiral galaxies can have ages that are incorrect by a factor of ten or more. In this paper we present a pilot study for four galaxies (NGC 628, NGC 1433, NGC 1365, and NGC 3351) from the PHANGS-HST survey. We describe methods to correct the …
We present the deepest optical photometry for any dwarf elliptical (dE) galaxy based on Hubble Space Telescope ACS observations of the Local Group dE galaxies NGC 147 and NGC 185. The resulting F606W and F814W color-magnitude diagrams are the first to reach below the main sequence turnoff in a dE galaxy, allowing us to determine full star formation histories in these systems. The ACS fields are located ~1.5 effective radii from the galaxy center to avoid photometric crowding. While our ACS pointings in both dEs show unambiguous evidence for old and intermediate age stars, the mean age in NGC 1…
Ultracool dwarfs represent a significant proportion of stars in the Milky Way,and deep samples of these sources have the potential to constrain the formation history and evolution of low-mass objects in the Galaxy. Until recently, spectral samples have been limited to the local volume (d<100 pc). Here, we analyze a sample of 164 spectroscopically-characterized ultracool dwarfs identified by Aganze et al. (2022) in the Hubble Space Telescope WFC3 Infrared Spectroscopic Parallel (WISP) Survey and 3D-HST. We model the observed luminosity function using population simulations to place constraints …
To What Extent Are Star Cluster Ages Encoded in Their Environments? Exploring the Spatial Distribution of Age-Related Information with PHANGS-HST Imaging and Convolutional Neural Networks
Massachusetts Institute of Technology（麻省理工学院）；Space Telescope Science Institute（太空望远镜科学研究所）；The Johns Hopkins University（约翰斯·霍普金斯大学）；Instituto de Astrofísica de La Plata, CONICET–UNLP（拉普拉塔天体物理研究所，阿根廷国家科学研究委员会-拉普拉塔国立大学）；University of Virginia Astronomy Department（弗吉尼亚大学天文系）；National Radio Astronomy Observatory（美国国家无线电天文台）
Ancient ($>$10 Gyr) globular clusters (GCs) show chemical abundance variations in the form of patterns among certain elements, e.g. N correlates with Na and anti-correlates with O. Recently, N abundance spreads have also been observed in massive star clusters that are significantly younger than old GCs, down to an age of $\sim$2 Gyr. However, so far N has been the only element found to vary in such young objects. We report here the presence of Na abundance variations in the intermediate age massive star clusters NGC 416 ($\sim$6.5 Gyr old) and Lindsay 1 ($\sim$7.5 Gyr old) in the Small Magella…
Forward-modelling Milky Way Cepheids: selection effects and physical priors in the Gaia-HST calibration
University of Oxford（牛津大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Johns Hopkins University（约翰斯·霍普金斯大学）；University of Portsmouth（朴茨茅斯大学）；CNRS & Sorbonne Université（法国国家科学研究中心与索邦大学）；Duke University（杜克大学）
UV Luminosity Functions from HST and JWST: A Possible Resolution to the High-Redshift Galaxy Abundance Puzzle and Implications for Cosmic Strings
McGill University（麦吉尔大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Cosmic Frontier Center, The University of Texas at Austin（德克萨斯大学奥斯汀分校宇宙前沿中心）；Massachusetts Institute of Technology（麻省理工学院）；Center for Theoretical Physics, A Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院莱因韦伯理论物理中心）
The sensitivity and angular resolution of photometric surveys executed by the Hubble Space Telescope (HST) enable studies of individual star clusters in galaxies out to a few tens of megaparsecs. The fitting of spectral energy distributions (SEDs) of star clusters is essential for measuring their physical properties and studying their evolution. We report on the use of the publicly available Code Investigating GALaxy Emission (CIGALE) SED fitting package to derive ages, stellar masses, and reddenings for star clusters identified in the Physics at High Angular resolution in Nearby GalaxieS-HST …
