Very low-luminosity galaxies in the early universe have observed sizes similar to single star cluster complexes
R. J. Bouwens, G. D. Illingworth, P. A. Oesch, M. Maseda, B. Ribeiro, M. Stefanon, D. Lam
备注：
The authors have decided to withdraw this manuscript from the Astrophysical Journal given the unprofessional footnotes in the original astro-ph posting, offering our sincere apologies
We compare the sizes and luminosities of 307 faint z=6-8 sources revealed by the Hubble Frontier Fields (HFF) program with sources in the nearby universe. Making use of the latest lensing models and data from the first four HFF clusters with an extensive suite of public lens models, we measure both the sizes and luminosities for 153 z~6, 101 z~7, and 53 z~8 galaxies. The sizes range over more than a decade from ~500 to <50 pc. Extremely small sizes are inferred for many of our lowest luminosity sources, reaching individual sizes as small as 10-30 pc (the smallest is 11(-6)(+28) pc). The uncertainty in these measures ranges from 80 pc for the largest sources to typically about 20 pc for the smallest. Such sizes are smaller than extrapolations of the size-luminosity relation, and expectations for the completeness of our faint samples, suggesting a likely break in the size-luminosity relation at ~-17 mag with size proportional to L**(0.50(-0.11)(+0.10)). The sizes and luminosities of the lowest-luminosity sources are similar to those of single star cluster complexes like 30 Doradus in the lower-redshift universe and -- in a few cases -- super star clusters. Remarkably, our identification of these compact, faint star-forming sources in the z~6-8 universe also allow us to set upper limits on the proto-globular cluster LF at z~6. Comparisons with recent models allow us to rule out (with some caveats) some scenarios for proto-globular cluster formation and set useful upper limits on other less extreme ones. Our results suggest we may be very close to discovering a bona-fide population of forming globular clusters at high redshift.
We analyze Spitzer GLIMPSE, MSX, and WMAP images of the Milky Way to identify 8 micron and free-free sources in the Galaxy. Seventy-two of the eighty-eight WMAP sources have coverage in the GLIMPSE and MSX surveys suitable for identifying massive star forming complexes (SFC). We measure the ionizing luminosity functions of the SFCs and study their role in the turbulent motion of the Galaxy's molecular gas. We find a total Galactic free-free flux f_ν = 46177.6 Jy; the 72 WMAP sources with full 8 micron coverage account for 34263.5 Jy (~75%), with both measurements made at ν=94GHz (W band). We f…
We compare the sizes and luminosities of faint $z=6$-8 galaxies magnified by the Hubble Frontier Fields (HFF) clusters with star-forming regions, as well as more evolved objects, in the nearby universe. Our high-redshift comparison sample includes 333 z=6-8 galaxies, for which size measurements were made as part of a companion study where lensing magnifications were estimated from various public models. Accurate size measurements for these sources are complicated by the lens model uncertainties, but other results and arguments suggest that faint galaxies are small, as discussed in a companion …
We study the galaxy clustering dependence on the $\left[\mathrm{O\scriptsize{II}}\right]$ emission line luminosity in the SDSS DR7 Main galaxy sample at mean redshift $z\sim0.1$. We select volume-limited samples of galaxies with different $\left[\mathrm{O\scriptsize{II}}\right]$ luminosity thresholds and measure their projected, monopole and quadrupole two-point correlation functions. We model these observations using the 1$h^{-1}\rm{Gpc}$ MultiDark Planck cosmological simulation and generate light-cones with the SUrvey GenerAtoR algorithm. To interpret our results, we adopt a modified (Sub)Ha…
We analyze parameters of the interstellar matter emission in star-forming complexes in the high metallicity galaxies NGC~628, NGC~2976, and NGC~3351, which have different morphological types. The relation between H$α$ emission and emission in CO and HI lines is considered along with the relation between H$α$ emission and dust emission in the infrared range (IR). The fluxes and surface brightnesses in the UV and IR correlate well with H$α$ emission. The HI emission also correlates well with H$α$, while the correlation between the CO and H$α$ emission is much less prominent. The ratio of the flu…
Local infrared (IR) luminosity functions (LFs) are necessary benchmarks for high-redshift IR galaxy evolution studies. Any accurate IR LF evolution studies require accordingly accurate local IR LFs. We present infrared galaxy LFs at redshifts redshifts of $z \leq 0.3$ from AKARI space telescope, which performed an all-sky survey in six IR bands (9, 18, 65, 90, 140 and 160 micron) with 10 times better sensitivity than its precursor IRAS. Availability of 160 micron filter is critically important in accurately measuring total IR luminosity of galaxies, covering across the peak of the dust emissio…
Luminous Compact Blue Galaxies (LCBGs) are compact, star-forming galaxies that are rarely observed in the local universe but abundant at z=1. This increase in LCBG number density over cosmic lookback time roughly follows the increase in the star formation rate density of the universe over the same period. We use publicly available data in the COSMOS field to study the evolution of the largest homogeneous sample of LCBGs to date by deriving their luminosity function in four redshift bins over the range $0.1\leq~z\leq1$. We find that over this redshift range, the characteristic luminosity (M$^{*…
We investigate the evolution of the H$β$+[OIII] and [OII] luminosity functions from $z \sim 0.8$ to $\sim5$ in four redshift slices per emission line using data from the High-{\it z} Emission Line Survey (HiZELS). This is the first time that the H$β$+[OIII] and [OII] luminosity functions have been studied at these redshifts in a self-consistent analysis. This is also the largest sample of [OII] and H$β$+[OIII] emitters (3475 and 3298 emitters, respectively) in this redshift range, with large co-moving volumes $\sim 1 \times 10^6$ Mpc$^{-3}$ in two independent volumes (COSMOS and UDS), greatly …
We introduce a prescription for the luminosity from accreting protostars into smoothed particle hydrodynamics simulation, and apply the method to simulations of five primordial minihalos generated from cosmological initial conditions. We find that accretion luminosity delays fragmentation within the halos, but does not prevent it. In halos that slowly form a low number of protostars, the accretion luminosity can reduce the number of fragments that are formed before the protostars start ionising their surroundings. However, halos that rapidly form many protostars become dominated by dynamical p…
Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate how the ionizing radiation from galaxies varies as a function of cosmic time. Important uncertainties in modeling reionization by galaxies revolve around the escape fraction and its luminosity and redshift dependence, a possible truncation of the galaxy luminosity function at the faint end, and an evolution in the production efficiency of Lyman-continuum ph…
We present new estimates of AGN accretion and star-formation luminosity in galaxies obtained for the local 12-$μ$m sample of Seyfert galaxies (12MGS), by performing a detailed broad-band spectral energy distribution (SED) decomposition including the emission of stars, dust heated by star formation and a possible AGN dusty torus. Thanks to the availability of data from the X-rays to the sub-millimetre, we constrain and test the contribution of the stellar, AGN and star-formation components to the SEDs. The availability of Spitzer-IRS low resolution mid-infrared (mid-IR) spectra is crucial to co…
The Square Kilometer Array (SKA) is expected to detect high-redshift galaxies with star formation rates (SFRs) up to two orders of magnitude lower than Herschel surveys and will thus boost the ability of radio astronomy to study extragalactic sources. The tight infrared-radio correlation offers the possibility of using radio emission as a dust-unobscured star formation diagnostic. However, the physics governing the link between radio emission and star formation is poorly understood, and recent studies have pointed to differences in the exact calibration required when radio is to be used as a s…
Supernovae Ia (SNe) can provide a unique window on the large scale structure (LSS) of the Universe at redshifts where few other observations are available, by solving the inversion problem (IP) consisting in reconstructing the LSS from its effects on the observed luminosity distance. So far the IP was solved assuming some restrictions about space-time, such as spherical symmetry for example, while we obtain for the first time solutions of the IP problem for arbitrary space-time geometries using deep learning. The method is based on the use of convolutional neural networks (CNN) trained on simu…
We study the luminosity function and the radial distribution of satellite galaxies within Milky Way sized haloes as predicted in Cold Dark Matter based models of galaxy formation, making use of numerical N-body techniques as well as three different semi-analytic model (SAMs) galaxy formation codes. We extract merger trees from very high-resolution dissipationless simulations of four Galaxy-sized DM haloes, and use these as common input for the semi-analytic models. We present a detailed comparison of our predictions with the observational data recently obtained on the Milky Way satellite lumin…
The Milky Way's most luminous, young and massive (M > 10^4 Msun) star clusters and OB associations have largely evaded detection despite knowledge of their surrounding H II regions. We search for these clusters and associations within the 40 star forming complexes from Rahman & Murray in the 13 most luminous WMAP free-free emission sources of the Galaxy. Selecting for objects with the dust-reddened colors of OB stars, we identify new candidate associations using the 2MASS point source catalog. In 40 star forming complexes searched, 22 contain cluster/association candidates with sizes and masse…
In a non-expanding universe surface brightness is independent of distance or redshift, while in an expanding universe it decreases rapidly with both. Similarly, for objects of the same luminosity, the angular radius of an object in a non-expanding universe declines with redshift, while in an expanding universe this radius increases for redshifts z>1.25. The author and colleagues have previously shown that data for the surface brightness of disk galaxies are compatible with a static universe with redshift linearly proportional to distance at all z (SEU hypothesis). In this paper we examine the …
We have carried out a systematic X-ray spectral analysis of a sample of low luminosity quasars (LLQSO) to investigate the nature of the central engines of these sources. The optically-selected LLQSO sample consists of close, known bright active galactic nuclei (AGN) which serves as an important link between the powerful quasars at higher redshift and local Seyfert galaxies. We find that although the bolometric luminosities of the LLQSOs are lower than those of the higher redshift quasars by almost an order of magnitude, their distribution of the Eddington rate $λ_{\rm Edd}$ is similar. We dete…
Swinburne University of Technology（斯威本科技大学）；Australian National University（澳大利亚国立大学）
We present a Bayesian hierarchical forward model for mapping the local luminosity-density field from heterogeneous redshift surveys. By dividing the survey volume into angular cells and redshift shells, we model the observed galaxy distribution directly in apparent-magnitude and redshift space. This allows us to infer cell-level luminosity functions and densities while preserving each survey's unique selection function. Simultaneously, the ensemble of cells constrains the cosmic-mean luminosity function, its redshift evolution, and the hyperparameters describing cell-to-cell variation. We appl…
The epochs of cosmic dawn and reionisation present promising avenues for understanding the role of dark matter (DM) in our cosmos. The first galaxies that populated the Universe during these eras resided in DM halos that were much less massive than their counterparts today. Consequently, observations of such galaxies can provide us with a handle on the clustering of DM in an otherwise currently inaccessible regime. In this work, we use high-redshift UV galaxy luminosity-function (UV LF) data from the Hubble Space Telescope to study the clustering properties of DM at small scales. In particular…
We investigate photometric properties of spiral arms and stellar complexes/associations inside these arms in the grand design NGC 628 (M74) galaxy.We analyze GALEX ultraviolet, optical UBVRI, and H-alpha? surface photometry data, including those obtained with 1.5 m telescope at the Maidanak Observatory. In the longer arm, the large and bright stellar complexes are located at regular intervals along the arm, but only farther from the galaxy center. They are joined with the narrow lane of dust, visible only in the infrared bands. The usual dust lane along the stellar arm inner side is seen there…
We report the first detailed measurement of the shape of the CO luminosity function at high redshift, based on $>$320 hr of the NSF's Karl G. Jansky Very Large Array (VLA) observations over an area of $\sim$60 arcmin$^2$ taken as part of the CO Luminosity Density at High Redshift (COLDz) survey. COLDz "blindly" selects galaxies based on their cold gas content through CO($J$=1$\to$0) emission at $z$$\sim$2-3 and CO($J$=2$\to$1) at $z$$\sim$5-7 down to a CO luminosity limit of log($L'_{\rm CO}$/K km s$^{-1}$ pc$^2$)$\simeq$9.5. We find that the characteristic luminosity and bright end of the CO …
The James Webb Space Telescope (JWST) is expected to observe galaxies at $z>10$ that are presently inaccessible. Here, we use a self-consistent empirical model, the UniverseMachine, to generate mock galaxy catalogues and lightcones over the redshift range $z=0-15$. These data include realistic galaxy properties (stellar masses, star formation rates, and UV luminosities), galaxy-halo relationships, and galaxy-galaxy clustering. Mock observables are also provided for different model parameters spanning observational uncertainties at $z<10$. We predict that Cycle 1 JWST surveys will very likely d…
Hydrogen in the Universe was (re)ionised between redshifts $z \approx 10$ and $z \approx 6$. The nature of the sources of the ionising radiation is hotly debated, with faint galaxies below current detection limits regarded as prime candidates. Here we consider a scenario in which ionising photons escape through channels punctured in the interstellar medium by outflows powered by starbursts. We take account of the observation that strong outflows occur only when the star formation density is sufficiently high, and estimate the galaxy-averaged escape fraction as a function of redshift and lumino…
A model of protostar mass and luminosity evolution in clusters gives new estimates of cluster age, protostar birthrate, accretion rate and mean accretion time. The model assumes constant protostar birthrate, core-clump accretion, and equally likely accretion stopping. Its parameters are set to reproduce the initial mass function, and to match protostar luminosity distributions in nearby star-forming regions. It obtains cluster ages and birthrates from the observed numbers of protostars and pre-main sequence (PMS) stars, and from the modal value of the protostar luminosity. In 31 embedded clust…
A galaxy's mean metallicity is usually closely correlated with its luminosity and mass. Consequently the most metal-poor galaxies in the local universe are dwarf galaxies. Blue compact dwarfs and tidal dwarfs tend to deviate from the metallicity-luminosity relation by being too metal-poor or too metal-rich for their luminosity, respectively. A less pronounced offset separates dwarf spheroidal (dSph) and dwarf irregular galaxies, making the former too metal-rich for their luminosity, which indicates different formation conditions for these two types of dwarfs. While environment (photo-evaporati…
Deep, near-infrared JHK-maps were observed for 10 nearby, grand-design, spiral galaxies using HAWK-I/VLT to study the distribution of young stellar clusters in them and thereby determine whether strong spiral perturbations can influence star formation. Complete, magnitude-limited candidate lists of star-forming complexes were obtained by searching within the K-band maps. The properties of the complexes were derived from (H-K)-(J-H) diagrams including the identification of the youngest complexes (i.e. <7 Myr) and the estimation of their extinction. Young stellar clusters with ages <7 Myr have s…
We describe the CO Luminosity Density at High-z (COLDz) survey, the first spectral line deep field targeting CO(1-0) emission from galaxies at $z=1.95-2.85$ and CO(2-1) at $z=4.91-6.70$. The main goal of COLDz is to constrain the cosmic density of molecular gas at the peak epoch of cosmic star formation. By targeting both a wide ($\sim$51 arcmin$^2$) and a deep area ($\sim$9 arcmin$^2$), the survey is designed to robustly constrain the bright end and the characteristic luminosity of the CO(1-0) luminosity function. An extensive analysis of the reliability of our line candidates, and new techni…
We present measurements of AGN type 1 luminosity function in the forbidden line [OIII]5007Åusing data from SDSS DR7. A special attention is paid to NLSy1. A new approach in calculating the luminosity function is present. We also account for the large-scale structure variations of the Universe density. The results obtained are compared with ones from the literature. A prediction of X-ray luminosity function based on our results shows an agreement with observations. One of our preliminary conclusions is that NLSy1 seems to occupy a more narrow range in the nuclear luminosity than BLSy1, but the …
EMU/GAMA: Refining Dust Extinction Corrections for Hα Luminosity Functions Using Radio-Based Calibration
Macquarie University（麦考瑞大学）；Universidade de Lisboa（里斯本大学）；Australian Astronomical Optics（澳大利亚天文光学）；Western Sydney University（西悉尼大学）；Australian National University（澳大利亚国立大学）；Ruhr Astroparticle and Plasma Physics Center (RAPP Center)（鲁尔亚原子与等离子体物理中心（RAPP中心））；Monash University（莫纳什大学）；Queensland University of Technology（昆士兰科技大学）；University of Hawai’i at Mānoa（夏威夷大学马诺阿分校）；Curtin University（科廷大学）
We present total infrared (IR) and ultraviolet (UV) luminosity functions derived from large representative samples of galaxies at z ~ 0, selected at IR and UV wavelengths from the IRAS IIFSCz catalogue, and the GALEX AIS respectively. We augment these with deep Spitzer and GALEX imaging of galaxies in the 11 Mpc Local Volume Legacy Survey (LVL), allowing us to extend these luminosity functions to lower luminosities (~10^6 L_sun), and providing good constraints on the slope of the luminosity function at the extreme faint end for the first time. Using conventional star formation prescriptions, w…
Thomson optical depth tau measurements from Planck provide new insights into the reionization of the universe. In pursuit of model-independent constraints on the properties of the ionising sources, we determine the empirical evolution of the cosmic ionizing emissivity. We use a simple two-parameter model to map out the evolution in the emissivity at z>~6 from the new Planck optical depth tau measurements, from the constraints provided by quasar absorption spectra and from the prevalence of Ly-alpha emission in z~7-8 galaxies. We find the redshift evolution in the emissivity dot{N}_{ion}(z) req…
We present a new suite of mock galaxy catalogs mimicking the low-redshift Universe, based on an updated halo occupation distribution (HOD) model and a scaling relation between optical properties and the neutral hydrogen (HI) content of galaxies. Our algorithm is constrained by observations of the luminosity function and luminosity- and colour-dependent clustering of SDSS galaxies, as well as the HI mass function and HI-dependent clustering of massive HI-selected galaxies in the ALFALFA survey. Mock central and satellite galaxies with realistic values of $r$-band luminosity, $g-r$ and $u-r$ col…
At the highest redshifts, z>6, several tens of luminous quasars have been detected. The search for fainter AGN, in deep X-ray surveys, has proven less successful, with few candidates to date. An extrapolation of the relationship between black hole (BH) and bulge mass would predict that the sample of z>6 galaxies host relatively massive BHs (>1e6 Msun), if one assumes that total stellar mass is a good proxy for bulge mass. At least a few of these BHs should be luminous enough to be detectable in the 4Ms CDFS. The relation between BH and stellar mass defined by local moderate-luminosity AGN in l…
