Detecting Massive Galaxies at High Redshift using the Dark Energy Survey
L. J. M. Davies, C. Maraston, D. Thomas, D. Capozzi, R. H. Wechsler, M. T. Busha, M. Banerji, F. Ostrovski, C. Papovich, B. X. Santiago, R. Nichol, M. A. G. Maia, L. N. da Costa
备注：
20 pages, 12 figures, MNRASaccepted. Missed reference added, minor change to Fig. 2
The Dark Energy Survey (DES) will be unprecedented in its ability to probe exceptionally large cosmic volumes to relatively faint optical limits. Primarily designed for the study of comparatively low redshift (z<2) galaxies with the aim of constraining dark energy, an intriguing byproduct of the survey will be the identification of massive (>10^(12.0) M_sun) galaxies at z>~4. This will greatly improve our understanding of how galaxies form and evolve. By both passively evolving the low redshift mass function and extrapolating the observed high redshift mass function, we find that such galaxies should be rare but nonetheless present at early times, with predicted number densities of ~0.02 deg^-2. The unique combination of depth and coverage that DES provides will allow the identification of such galaxies should they exist - potentially identifying hundreds of such sources. We then model possible high redshift galaxies and determine their detectability using the DES filter sets and depths. We model sources with a broad range stellar properties and find that for these galaxies to be detected they must be either sufficiently young, high mass and/or relatively dust free (E(B-V)<0.45) - with these parameters jointly affecting each galaxy's detectability. We also propose colour-colour selection criteria for the identification of both pristine and dusty sources and find that, although contamination fractions will be high, the most reliable candidate massive high redshift galaxies are likely to be identifiable in the DES data through prioritisation of colour-selected sources.
We investigate the possibility to detect the integrated Sachs-Wolfe (ISW) effect by cross-correlating 21-cm surveys at high redshifts with galaxies, in a way similar to the usual CMB-galaxy cross-correlation. The high-redshift 21-cm signal is dominated by CMB photons that travel freely without interacting with the intervening matter, and hence its late-time ISW signature should correlate extremely well with that of the CMB at its peak frequencies. Using the 21-cm temperature brightness instead of the CMB would thus be a further check of the detection of the ISW effect, measured by different in…
Space based gravitational wave astronomy will open a completely new window on the Universe and massive black holes binaries are expected to be among the primary actors on this upcoming stage. The New Gravitational-wave Observatory (NGO) is a space interferometer proposal derived from the former Laser Interferometer Space Antenna (LISA) concept. We describe here its capabilities of observing massive black hole binaries throughout the Universe, measuring their relevant parameters (masses, spins, distance to the observer) to high precision. The statistical properties of the population of detected…
Upcoming cosmic microwave background (CMB) experiments will measure temperature fluctuations on small angular scales with unprecedented precision. Small-scale CMB fluctuations are a mixture of late-time effects: gravitational lensing, Doppler shifting of CMB photons by moving electrons (the kSZ effect), and residual foregrounds. We propose a new statistic which separates the kSZ signal from the others, and also allows the kSZ signal to be decomposed in redshift bins. The decomposition extends to high redshift, and does not require external datasets such as galaxy surveys. In particular, the hi…
The detection of individual ionized bubbles in HI 21-cm maps is one of the most promising, direct probes of the epoch of reionization(EoR). Atleast 1000 hrs of observation would be required for such a detection with either the currently functioning GMRT or the upcoming MWA. Considering the large investment of telescope time it is essential to identify the``optimal redshift'' where the prospects of a detection are most favourable. We find that the optimal redshift is determined by a combination of instrument dependent factors and the evolution of the neutral fraction x_HI. We find that the reds…
We investigate the prospects of extending observations of high redshift QSOs to z>8 by means of a very wide-area near-infrared slitless spectroscopic survey, e.g. the planned survey with the European Space Agency's Euclid telescope. For any QSOs at z>8.06 the strong Lyman-alpha line will enter the wavelength range of the Euclid near-infrared spectrometer and imaging photometer (NISP). We perform a detailed simulation of Euclid NISP slitless spectroscopy (with the parameters of the wide survey) in an artificial field containing QSO spectra at all redshifts up to z=12. The simulation spectra are…
Modified gravity and massive neutrino cosmologies are two of the most interesting scenarios that have been recently explored to account for possible observational deviations from the concordance $Λ$-cold dark matter ($Λ$CDM) model. In this context, we investigated the large-scale structure of the Universe by exploiting the \dustp simulations that implement, simultaneously, the effects of $f(R)$ gravity and massive neutrinos. To study the possibility of breaking the degeneracy between these two effects, we analysed the redshift-space distortions in the clustering of dark matter haloes at differ…
The amplitude of weak lensing should increase with source distance, rising steeply behind a lens and saturating at high redshift, providing a model-independent means of measuring cosmic geometry. We measure the amplitude of weak lensing with redshift for three massive clusters, A370 (z=0.375), ZwCl0024+17 (z=0.395) and RXJ1347-11 (z=0.451), using deep, three-colour Subaru imaging. We define the depth of lensed populations with reference to the COSMOS and GOODS fields, providing a consistency check of photo-z estimates over a wide range of redshift and magnitude. The predicted distance-redshift…
Testing theories of hierarchical structure formation requires estimating the distribution of galaxy morphologies and its change with redshift. One aspect of this investigation involves identifying galaxies with disturbed morphologies (e.g., merging galaxies). This is often done by summarizing galaxy images using, e.g., the CAS and Gini-M20 statistics of Conselice (2003) and Lotz et al. (2004), respectively, and associating particular statistic values with disturbance. We introduce three statistics that enhance detection of disturbed morphologies at high-redshift (z ~ 2): the multi-mode (M), in…
Mass and concentration of clusters of galaxies are related and evolving with redshift. We study the properties of a sample of 31 massive galaxy clusters at high redshift, 0.8 < z < 1.5, using weak and strong lensing observations. Concentration is a steep function of mass, c_{200} ~M_{200}^{-0.83 +-0.39}, with higher-redshift clusters being less concentrated. Mass and concentration from the stacked analysis, M_{200}=(4.1+-0.4)x10^{14}M_Sun/h and c_{200}=2.3+-0.2, are in line with theoretical results extrapolated from the local universe. Clusters with signs of dynamical activity preferentially f…
Massive compact galaxies seem to be more common at high redshift than in the local universe, especially in denser environments. To investigate the fate of such massive galaxies identified at z~2 we analyse the evolution of their properties in three cosmological hydrodynamical simulations that form virialised galaxy groups of mass ~10^13 Msun hosting a central massive elliptical/S0 galaxy by redshift zero. We find that at redshift ~2 the population of galaxies with M_*> 2 10^10 Msun is diverse in terms of mass, velocity dispersion, star formation and effective radius, containing both very compa…
Fast radio bursts (FRB) probe the electron density of the universe along the path of propagation, making high redshift FRB sensitive to the helium reionization epoch. We analyze the signal to noise with which a detection of the amplitude of reionization can be made, and its redshift, for various cases of future FRB survey samples, assessing survey characteristics including total number, redshift distribution, peak redshift, redshift depth, and number above the reionization redshift, as well as dependence on reionization redshift. We take into account scatter in the dispersion measure due to an…
We place firm upper limits on the global accretion history of massive black holes at z>5 from the recently measured unresolved fraction of the cosmic X-ray background. The maximum allowed unresolved intensity observed at 1.5 keV implies a maximum accreted-mass density onto massive black holes of rho_acc < 1.4E4 M_sun Mpc^{-3} for z>5. Considering the contribution of lower-z AGNs, the value reduces to rho_acc < 0.66E4 M_sun Mpc^{-3}. The tension between the need for the efficient and rapid accretion required by the observation of massive black holes already in place at z>7 and the strict upper …
We use a large N-body simulation to examine the detectability of HI in emission at redshift z ~ 1, and the constraints imposed by current observations on the neutral hydrogen mass function of galaxies at this epoch. We consider three different models for populating dark matter halos with HI, designed to encompass uncertainties at this redshift. These models are consistent with recent observations of the detection of HI in emission at z ~ 0.8. Whilst detection of 21 cm emission from individual halos requires extremely long integrations with existing radio interferometers, such as the Giant Mete…
The detection of galaxy clusters in present and future surveys enables measuring mass-to-light ratios, clustering properties or galaxy cluster abundances and therefore, constraining cosmological parameters. We present a new technique for detecting galaxy clusters, which is based on the Matched Filter Algorithm from a Bayesian point of view. The method is able to determine the position, redshift and richness of the cluster through the maximization of a filter depending on galaxy luminosity, density and photometric redshift combined with a galaxy cluster prior. We tested the algorithm through re…
Stable massive neutral particles emitted by astrophysical sources undergo deflection under the gravitational potential of our own galaxy. The deflection angle depends on the particle velocity and therefore non-relativistic particles will be deflected more than relativistic ones. If these particles can be detected through neutrino telescopes, cosmic ray detectors or directional dark matter detectors, their arrival directions would appear aligned on the sky along the source-lens direction. On top of this deflection, the arrival direction of non-relativistic particles is displaced with respect to…
The 21cm forest -- HI absorption features in the spectra of high-redshift radio sources -- can potentially provide a unique probe of the largely neutral intergalactic medium (IGM) during the epoch of reionization. We present simulations of the 21cm forest due to the large scale structure of the reionization-era IGM, including a prescription for x-ray heating and the percolation of photoionization bubbles. We show that, if detected with future instruments such as the Square Kilometer Array (SKA), the 21cm forest can provide a significant constraint on the thermal history of the IGM. Detection w…
Detecting redshift space distortions with forthcoming 21cm intensity maps from MeerKLASS
University of Portsmouth（朴茨茅斯大学）；The University of Edinburgh（爱丁堡大学）；Instituto de Física de Cantabria (IFCA), CSIC-Univ. de Cantabria（坎塔布里亚物理研究所（IFCA），西班牙科学研究中心-坎塔布里亚大学）
In this work we present an application of general extreme value statistics (GEV) to very massive single clusters at high and low redshifts. After introducing the formalism, we apply this statistics to four very massive high redshift clusters. Those clusters comprise ACT-CL J0102-4915 with a mass of M_200m=(2.16+/-0.32)x10^{15} M_sun at a redshift of z=0.87, SPT-CL J2106-5844 with a mass of M_200m=(1.27+/-0.21)x10^{15} M_sun at z=1.132 and two clusters found by the XMM-Newton Distant Cluster Project survey: XMMU J2235.32557 with a mass of M_200c= (7.3+/-1.3)x10^{14} M_sun located at a redshift …
Galactic nuclei host central massive objects either in the form of supermassive black holes or nuclear stellar clusters. Recent investigations have shown that both components co-exist in at least a few galaxies. In this paper we explore the possibility of a connection between nuclear star clusters and black holes that establishes at the moment of their formation. We here model the evolution of high redshift discs, hosted in dark matter halos with virial temperatures 10^4 K, whose gas has been polluted with metals just above the critical metallicity for fragmentation. A nuclear cluster forms as…
From a search of a portion of the sky covered by the SDSS and UKIDSS databases, we have located 2 galaxies at z~0.5 that have properties similar to those of the luminous passive compact galaxies found at z~2.5. From Keck moderate-resolution spectroscopy and laser-guided adaptive-optics imaging of these galaxies, we can begin to put together a more detailed picture of what their high-redshift counterparts might be like. Spectral-synthesis models that fit the u to K photometry also seem to give good fits to the spectral features. From these models, we estimate masses in the range of 3-4 10^11 M_…
We explore the possibility of detecting the first galaxies with the next generation of space-based far infrared (FIR) telescopes by applying an analytical model of primordial dust emission. Our results indicate that FIR/sub-mm sources at $z \gtrsim 7$ will experience a strong negative K-correction. Systems of a given virial mass would exhibit larger dust luminosities at higher $z$, as a consequence of the increase in dust temperature driven by the higher temperature floor set by the cosmic microwave background. In addition, high-$z$ systems are more concentrated, which enhances the heating eff…
Massive clusters of galaxies have been found as early as 3.9 Billion years (z=1.62) after the Big Bang containing stars that formed at even earlier epochs. Cosmological simulations using the current cold dark matter paradigm predict these systems should descend from "proto-clusters" - early over-densities of massive galaxies that merge hierarchically to form a cluster. These proto-cluster regions themselves are built-up hierarchically and so are expected to contain extremely massive galaxies which can be observed as luminous quasars and starbursts. However, observational evidence for this scen…
We investigate the possibility of detecting baryon acoustic oscillation features in the cosmic matter distribution by 3d weak lensing. Baryon oscillations are inaccessible even to weak lensing tomography because of wide line-of-sight weighting functions and require a specialized approach via 3d shear estimates. We quantify the uncertainty of estimating the matter spectrum amplitude at the baryon oscillations wave vectors by a Fisher-matrix approach with a fixed cosmology and show in this way that future weak lensing surveys such as EUCLID and DES are able to pick up the first four wiggles, wit…
Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts - that is, increased rates of star formation - in the most massive dark matter halos at early epochs. However, it remains unknown how soon after the Big Bang such massive starburst progenitors exist. The measured redshift distribution of dusty, massive starbursts has long been suspected to be biased low in redshift owing to selection effects, as confirmed by recent findings of systems out to redshift z~5. Here we repor…
High redshift radio galaxies are among the largest, most luminous, most massive, and most beautiful objects in the Universe. They are generally identified from their radio emission, thought to be powered by accretion of matter onto supermassive black holes in the nuclei of their host galaxies. Observations show that they are energetic sources of radiation throughout most of the electromagnetic spectrum, including relativistic plasma, gas and dust, stars and the active galactic nuclei (AGN). 1 HzRGs are inferred to be extremely massive, including old stars (up to $\sim$ 10$^{12}$ M$_{\odot}$), …
We investigate the evolution of the dark matter density profiles of the most massive galaxy clusters in the Universe. Using a `zoom-in' procedure on a large suite of cosmological simulations of total comoving volume of $3\,(h^{-1}\,\rm Gpc)^3$, we study the 25 most massive clusters in four redshift slices from $z\sim 1$ to the present. The minimum mass is $M_{500} > 5.5 \times 10^{14}$ M$_{\odot}$ at $z=1$. Each system has more than two million particles within $r_{500}$. Once scaled to the critical density at each redshift, the dark matter profiles within $r_{500}$ are strikingly similar from…
Luminous high-redshift QSOs are thought to exist within the most massive dark matter haloes in the young Universe. As a consequence they are likely to be markers for biased, over-dense regions where early galaxies cluster, regions that eventually grow into the groups and clusters seen in the lower redshift universe. In this paper we explore the clustering of galaxies around z ~ 5 QSOs as traced by Lyman Break Galaxies (LBGs). We target the fields of three QSOs using the same optical imaging and spectroscopy techniques used in the ESO Remote Galaxy Survey (ERGS, Douglas et al. 2009, 2010), whic…
The dwarf galaxies of the Local Group are believed to be similar to the most abundant galaxies during the epoch of reionization (z>6). As a result of their proximity, there is a wealth of information that can be obtained about these galaxies; however, due to their low surface brightnesses, detecting their progenitors at high redshifts is challenging. We compare the physical properties of these dwarf galaxies to those of galaxies detected at high redshifts using Hubble Space Telescope and Spitzer observations and consider the promise of the upcoming James Webb Space Telescope on the prospects f…
Large-scale structure surveys in the coming years will measure the redshift-space power spectrum to unprecedented accuracy, allowing for powerful new tests of the LambdaCDM picture as well as measurements of particle physics parameters such as the neutrino masses. We extend the Time-RG perturbative framework to redshift space, computing the power spectrum P_s(k,mu) in massive neutrino cosmologies with time-dependent dark energy equations of state w(z). Time-RG is uniquely capable of incorporating scale-dependent growth into the P_s(k,mu) computation, which is important for massive neutrinos as…
We present Gran-Telescopio-Canarias/OSIRIS optical spectra of 4 of the most compact and massive early-type galaxies in the Groth Strip Survey at redshift z~1, with effective radii Reff=0.5-2.4 kpc and photometric stellar masses Mstar=1.2-4x10^11 Msun. We find these galaxies have velocity dispersions sigma=156-236 km/s. The spectra are well fitted by single stellar population models with approximately 1 Gyr of age and solar metallicity. We find that: i) the dynamical masses of these galaxies are systematically smaller by a factor of ~6 than the published stellar masses using BRIJK photometry; i…
There are observations of 15 high-redshift massive galaxy clusters, which have an extremely small probability with a purely Gaussian initial curvature perturbation. Here we revisit the estimation of the contribution of non-Gaussianities to the cluster mass function and point out serious problems that have resulted in the application of the mass function out of the range of its validity. We remedy the situation and show that the values of f_NL previously claimed to completely reconcile (i.e. at ~100% confidence) the existence of the clusters with LambdaCDM are unphysically small. However, for W…
Inferring, not just detecting: metrics for high-redshift sources observed with third-generation gravitational-wave detectors
Universitá degli Studi di Milano-Bicocca（米兰比可卡大学）；INFN, Sezione di Milano-Bicocca（意大利国家核物理研究所米兰比可卡分部）；Université de Genève（日内瓦大学）；University of Birmingham（伯明翰大学）
We present a study of galaxy populations in the central region of the IRAC-selected, X-ray detected galaxy cluster Cl J1449+0856 at z=2. Based on a sample of spectroscopic and photometric cluster members, we investigate stellar populations and morphological structure of cluster galaxies over an area of ~0.7Mpc^2 around the cluster core. The cluster stands out as a clear overdensity both in redshift space, and in the spatial distribution of galaxies close to the center of the extended X-ray emission. The cluster core region (r<200 kpc) shows a clearly enhanced passive fraction with respect to f…
Gaussian-Process Emulation of the Redshift-Space Halo Power Spectrum Monopole in Cosmologies with Massive Neutrinos
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；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）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与前沿科学研究院）；Chinese Academy of Sciences South America Center for Astronomy (CASSACA), National Astronomical Observatories, Chinese Academy of Sciences（中国科学院南美天文中心）
The stellar mass-halo mass relation is a key constraint in all semi-analytic, numerical, and semi-empirical models of galaxy formation and evolution. However, its exact shape and redshift dependence remain debated. Several recent works support a relation in the local Universe steeper than previously thought. Based on the comparisons with a variety of data on massive central galaxies, we show that this steepening holds up to z~1, for stellar masses Mstar>2e11 Msun. Specifically, we find significant evidence for a high-mass end slope of β>0.35-0.70, instead of the usual β~0.20-0.30 reported by a…
In this work we propose a novel method for testing the validity of the fiducial LCDM cosmology by measuring the cumulative distribution function of the most massive haloes in a sample of subvolumes of identical size tiled on the sky at a fixed redshift. The fact that the most massive clusters probe the high-mass tail of the mass function, where the difference between LCDM and alternative cosmological models is strongest, makes our method particularly interesting as a cosmological probe. We utilise general extreme value statistics (GEV) to obtain a cumulative distribution function of the most m…
We critically investigate current statistical tests applied to high redshift clusters of galaxies in order to test the standard cosmological model and describe their range of validity. We carefully compare a sample of high-redshift, massive, galaxy clusters with realistic Poisson sample simulations of the theoretical mass function, which include the effect of Eddington bias. We compare the observations and simulations using the following statistical tests: the distributions of ensemble and individual existence probabilities (in the >M,>z sense), the redshift distributions, and the 2d Kolmogoro…
Recent studies have shown that massive quiescent galaxies at high redshift are much more compact than present-day galaxies of the same mass. Here we compare the radial stellar density profiles and the number density of a sample of massive galaxies at z ~ 2.3 to nearby massive elliptical galaxies. We confirm that the average stellar densities of the z ~ 2.3 galaxies within the effective radius, rho(<r_e), are two orders of magnitude higher than those of local elliptical galaxies of the same stellar mass. However, we also find that the densities measured within a constant physical radius of 1 kp…
Massive galaxy clusters are interesting astrophysical and cosmological study objects, but are relatively rare. In the redshift range z = 0.25 to 0.5 which is, for example, a favourable region for gravitational lensing studies, about 100 such systems are known. Most of them have been studied in X-rays. In this paper we study the six remaining massive clusters in this redshift interval in the highly complete CLASSIX survey which have so far not been observed with sufficiently deep exposures in X-rays. With data from our new XMM-Newton observations we characterise their structures, derive X-ray p…
The Fourier-space galaxy bispectrum is complex, with the imaginary part arising from leading-order relativistic corrections, due to Doppler, gravitational redshift and related line-of-sight effects in redshift space. The detection of the imaginary part of the bispectrum is potentially a smoking gun signal of relativistic contributions. We investigate whether next-generation spectroscopic surveys could make such a detection. For a Stage IV spectroscopic $Hα$ survey similar to Euclid, we find that the cumulative signal to noise of this relativistic signature is $\mathcal{O}(10)$. Long-mode relat…
Galaxy formation models invoke the presence of strong feedback mechanisms that regulate the growth of massive galaxies at high redshifts. In this paper we aim to: (1) confirm spectroscopically the redshifts of a sample of massive galaxies selected with photometric redshifts z > 2.5; (2) investigate the properties of their stellar and interstellar media; (3) detect the presence of outflows, and measure their velocities. To achieve this, we analysed deep, high-resolution (R~2000) FORS2 rest-frame UV spectra for 11 targets. We confirmed that 9 out of 11 have spectroscopic redshifts z > 2.5. We al…
Aims. We present a determination of the intrinsic colors and ages of galaxies at very high redshift, in particular old galaxies (OGs) within extremely red objects (EROs). To date, the definition of EROs has been restricted to objects with z<2.5, however, here consider objects with the same properties but shifted to higher redshifts (z>2.5). We therefore, refer to these objects as very high-redshift EROs (Z-EROS, herein). Methods. We analyze 63,550 galaxies selected in the XMM-LSS field. To obtain a reasonably sized sample of EROs, it is essential to consider a very wide area surveys. We identi…
The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish between a cosmological constant and a dynamical dark energy field. In particular, the recent detection of very massive clusters of galaxies at high redshifts has attracted significant interest as a possible indication of a failure of the standard LCDM model. Several attempts have been made in order to explain such detections in the context of non-Gaussian sc…
We identify a sample of 1959 massive clusters of galaxies in the redshift range of 0.7<z<1.0 from the survey data of Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE). These clusters are recognized as the overdensity regions around the SDSS luminous red galaxies, having a richness greater than 15 or an equivalent mass M_{500} \ge 2.5*10^{14}M_{\odot}. Among them, 1505 clusters are identified for the first time, which significantly enlarge the number of high-redshift clusters of z>0.75. By comparing them with clusters at lower redshifts, we confirm that richer clust…
Several bright and massive galaxy candidates at high redshifts have been recently observed by the James Webb Space Telescope. Such early massive galaxies seem difficult to reconcile with standard $Λ$ Cold Dark Matter model predictions. We discuss under which circumstances such observed massive galaxy candidates can be explained by introducing primordial non-Gaussianity in the initial conditions of the cosmological perturbations.
The presence of massive black holes (BHs) with masses of order $10^9\rm\, M_\odot$, powering bright quasars when the Universe was less than 1 Gyr old, poses strong constraints on their formation mechanism. Several scenarios have been proposed to date to explain massive BH formation, from the low-mass seed BH remnants of the first generation of stars to the massive seed BHs resulting from the rapid collapse of massive gas clouds. However, the plausibility of some of these scenarios to occur within the progenitors of high-z quasars has not yet been thoroughly explored. In this work, we investiga…
Using data drawn from the DEEP2 and DEEP3 Galaxy Redshift Surveys, we investigate the relationship between the environment and the structure of galaxies residing on the red sequence at intermediate redshift. Within the massive (10 < log(M*/Msun) < 11) early-type population at 0.4 < z <1.2, we find a significant correlation between local galaxy overdensity (or environment) and galaxy size, such that early-type systems in higher-density regions tend to have larger effective radii (by ~0.5 kpc or 25% larger) than their counterparts of equal stellar mass and Sersic index in lower-density environme…
We present the development of a photometrically selected massive galaxy catalog, targeting Luminous Red Galaxies (LRGs) and massive blue galaxies at redshifts $z\geq 0.55$. Massive galaxy candidates are selected using infrared/optical color-color cuts, with optical data from Sloan Digital Sky Survey (SDSS) and infrared data from "unWISE" forced photometry derived from the Wide-field Infrared Survey Explorer (WISE). The selection method is based on previously developed techniques to select LRGs with $z>0.5$, and is optimized using receiver operating characteristic (ROC) curves. The catalog cont…
We examine the relation between surface brightness, velocity dispersion and size$-$the fundamental plane$-$for quiescent galaxies at intermediate redshifts in the COSMOS field. The COSMOS sample consists of $\sim150$ massive quiescent galaxies with an average velocity dispersion $σ\sim 250$ km s$^{-1}$ and redshifts between $0.2<z<0.8$. More than half of the galaxies in the sample are compact. The COSMOS galaxies exhibit a tight relation ($\sim0.1$ dex scatter) between surface brightness, velocity dispersion and size. At a fixed combination of velocity dispersion and size, the COSMOS galaxies …
We study the effect of magnetic braking due to a primordial magnetic field in the context of the formation of massive ($\gtrsim 10^{4} M_\odot$) direct collapse black holes (DCBHs) at high redshifts. Under the assumption of axial symmetry, we analytically compute the effect of magnetic braking on the angular momentum of gas collapsing into the potential well of massive dark matter haloes ($\simeq 10^{7-9} M_\odot$) which are spun up by gravitational tidal torques. We find that a primordial magnetic field of strength $B_0\simeq 0.1$~nG (comoving) can remove the initial angular momentum gained b…
We explore the possibility of detecting Baryon Acoustic Oscillations (BAO) solely from gravitational wave observations of binary neutron star mergers with third generation (3G) gravitational wave (GW) detectors like Cosmic Explorer and the Einstein Telescope. These measurements would provide a new independent probe of cosmology. The detection of the BAO peak with current generation GW detectors (solely from GW observations) is not possible because i) unlike galaxies, the GW mergers are poorly localized and ii) there are not enough merger events to probe the BAO length scale. With the 3G GW det…
We use a dense redshift survey in the foreground of the Subaru GTO2deg^2 weak lensing field (centered at $α_{2000}$ = 16$^h04^m44^s$;$δ_{2000}$ =43^\circ11^{\prime}24^{\prime\prime}$) to assess the completeness and comment on the purity of massive halo identification in the weak lensing map. The redshift survey (published here) includes 4541 galaxies; 4405 are new redshifts measured with the Hectospec on the MMT. Among the weak lensing peaks with a signal-to-noise greater that 4.25, 2/3 correspond to individual massive systems; this result is essentially identical to the Geller et al. (2010) t…
Using cosmological, radiation-hydrodynamic simulations targeting a rare $\approx \, 2 \times 10^{12} \, \rm M_\odot$ halo at $z \, = \, 6$, we show that the number counts and internal properties of satellite galaxies within the massive halo are sensitively regulated by a combination of local stellar radiative feedback and strong tidal forces. Radiative feedback operates before the first supernova explosions erupt and results in less tightly-bound galaxies. Satellites are therefore more vulnerable to tidal stripping when they accrete onto the main progenitor and are tidally disrupted on a signi…
We explore the possibility of detecting the first galaxies with the next generation Origins Space Telescope (OST) by applying an analytical model of primordial dust emission. By analysing source densities as a function of redshift (z), and considering deep-field exposures with the Origins Survey Spectrometer, we estimate that the redshift horizon for detecting one individual source would be above z~7 for systems with dust-to-metal ratios higher than those expected for typical primeval galaxies. On the other hand, if confusion limits could be overcome, the Far-infrared Imager and Polarimeter wo…
