Deep Extragalactic VIsible Legacy Survey (DEVILS): first data release covering the D10 (COSMOS) region

To develop galaxy-targeting approaches, the gravitational-wave community built a catalog of stellar mass in the local universe based on the Two Micron All Sky Survey (2MASS) spectroscopic and photometric redshift surveys. By cleaning and supplementing this catalog, the present work aims to establish a near-infrared flux-limited sample to map both stellar mass and star formation rate (SFR) over the full sky. The 2MASS spectroscopic and photometric redshift surveys are crossmatched with the HyperLEDA database and the Local Volume sample at d < 11 Mpc, providing a flux-limited sample with revised distance estimates and corrections for incompleteness out to 350 Mpc. Scaling relations with stellar mass as a function of morphology are used to construct an SFR cosmography in the local universe. Stellar-mass and SFR densities converge toward values compatible with deep-field observations beyond 100 Mpc. The 3D distribution of these two tracers is consistent with the distribution of matter deduced from cosmic flows. With spectroscopic redshifts available for about half of the ∼400,000 galaxies within 350 Mpc and photometric distances with a 12% uncertainty available for the other half, the present sample may find applications in both cosmology and astroparticle physics. The present work provides, in particular, new bases for modeling the large- and intermediate-scale anisotropies observed at ultra-high energies. The distribution of magnetic fields at megaparsec scales, which can be deduced from the 3D distribution of matter, is inferred to be crucial in shaping the ultra-high-energy sky.

Context. For more than two decades we have known that galaxy morphological segregation is present in the Local Universe. It is important to see how this relation evolves with cosmic time. Aims. To investigate how galaxy assembly took place with cosmic time, we explore the evolution of the morphology-density relation up to redshift z 1 using about 10 000 galaxies drawn from the zCOSMOS Galaxy Redshift Survey. Taking advantage of accurate HST/ACS morphologies from the COSMOS survey, of the well-characterised zCOSMOS 3D environment, and of a large sample of galaxies with spectroscopic redshift, we want to study here the evolution of the morphology-density relation up to z 1 and its dependence on galaxy luminosity and stellar mass. The multi-wavelength coverage of the field also allows a first study of the galaxy morphological segregation dependence on colour. We further attempt to disentangle between processes that occurred early in the history of the Universe or late in the life of galaxies. Methods. The zCOSMOS field benefits of high-resolution imaging in the F814W filter from the Advanced Camera for Survey (ACS). We use standard morphology classifiers, optimised for being robust against band-shifting and surface brightness dimming, and a new, objective, and automated method to convert morphological parameters into early, spiral, and irregular types. We use about 10 000 galaxies down to I AB = 22.5 with a spectroscopic sampling rate of 33% to characterise the environment of galaxies up to z 1 from the 100 kpc scales of galaxy groups up to the 100 Mpc scales of the cosmic web. The evolution of the morphology-density relation in different environments is then studied for luminosity and stellar-mass selected, volume-limited samples of galaxies. The trends are described and related to the various physical processes that could play a relevant role in the build-up of the morphology-density relation. Results. We confirm that the morphological segregation is present up to z 1 for luminosity-selected, volume-limited samples. The behaviour of the morphology-density relation gets flatter at fixed masses expecially above 10 10.6 M . We suggest the existence of a critical mass above which the physical processes governing galaxy stellar mass also determine the shaping of the galaxy more than its environment. We finally show that at a fixed morphology there is still a residual variation in galaxy colours with density. Conclusions. The observed evolution with redshift of the morphology-density relation offers an opportunity to trace the effect of nature and nurture as a function of environment. Even though it is based mainly on a biased view, the environmental dependence of the morphological evolution for luminosity-selected, volume-limited samples seems to indicate that nurture is in play. On the other hand, the lack of evolution observed for earlytype and spiral galaxies that are more massive than 10 10.8 M independents of the environment indicates that nature has imprinted these properties early in the life of these galaxies. We conclude that the relative contribution of nature and nurture in different environments strongly depends on the mass of galaxies, consistent with a downsizing scenario.

We present catalogues of calibrated photometry and spectroscopic redshifts in the Extended Groth Strip, intended for studies of photometric redshifts (photo-z’s). The data includes ugriz photometry from Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) and Y-band photometry from the Subaru Suprime camera, as well as spectroscopic redshifts from the DEEP2, DEEP3, and 3D-HST surveys. These catalogues incorporate corrections to produce effectively matched-aperture photometry across all bands, based upon object size information available in the catalogue and Moffat profile point spread function fits. We test this catalogue with a simple machine learning-based photometric redshift algorithm based upon Random Forest regression, and find that the corrected aperture photometry leads to significant improvement in photo-z accuracy compared to the original SExtractor catalogues from CFHTLS and Subaru. The deep ugrizY photometry and spectroscopic redshifts are well suited for empirical tests of photometric redshift algorithms for LSST. The resulting catalogues are publicly available at http://d-scholarship.pitt.edu/36064/. We include a basic summary of the strategy of the DEEP3 Galaxy Redshift Survey to accompany the recent public release of DEEP3 data.

We present deep optical imaging observations of 2 square degree area, covered by the Cosmic Evolution Survey (COSMOS), made by the prime-focus camera (Supreme-Cam) on the 8.2 m Subaru Telescope. Observations were done in six broadband [B (4459.7 A), g' (4723.1 A), V (5483.8 A), r' (6213.0 A), i' (7640.8 A), z' (8855.0 A)] and one narrowband (NB816) filters. A total of 106 galaxies were detected to i' ~ 26.5 mag. These data, combined with observations at u* and K-band are used to construct the photometric catalogs for the COSMOS, to measure their photometric redshifts, multiband spectral energy distributions, and stellar masses, and to identify high-redshift candidates. This catalog provides multi-wave band data for scientific analysis of the COSMOS survey.

The measurement of redshifts for gamma-ray bursts (GRBs) is an important issue for the study of the high redshift universe and cosmology. We are constructing a program to estimate the redshifts for GRBs from the original Swift light curves and spectra, aiming to get redshifts for the Swift bursts without spectroscopic or photometric redshifts. We derive the luminosity indicators from the light curves and spectra of each burst, including the lag time between low and high photon energy light curves, the variability of the light curve, the peak energy of the spectrum, the number of peaks in the light curve, and the minimum rise time of the peaks. These luminosity indicators can each be related directly to the luminosity, and we combine their independent luminosities into one weighted average. Then with our combined luminosity value, the observed burst peak brightness, and the concordance redshift–distance relation, we can derive the redshift for each burst. In this paper, we test the accuracy of our method on 107 bursts with known spectroscopic redshift. The reduced χ2 of our best redshifts (zbest) compared with known spectroscopic redshifts (zspec) is 0.86, and the average value of log10(zbest/zspec) is 0.01, with this indicating that our error bars are good and our estimates are not biased. The rms scatter of log10(zbest/zspec) is 0.26, with a comparison of 0.30 for rms of log10(zspec). We made a selection on bursts with relatively accurate redshift estimation. The rms of log(zbest/zspec) decreases to 0.19, and the rms scatter of log10(zspec)for this subsample is 0.28. For Swift bursts measured over a relatively narrow energy band, the uncertainty in determining the peak energy is one of the main restrictions on our accuracy. Although the accuracy of our zbest values are not as good as that of spectroscopic redshifts, it is very useful for demographic studies, as our sample is nearly complete and the redshifts do not have the severe selection effects associated with optical spectroscopy.

We use the deepest and the most comprehensive photometric data currently available for GOODS-South galaxies to measure their photometric redshifts. The photometry includes VLT/VIMOS (U-band), HST/ACS (F435W, F606W, F775W, and F850LP bands), VLT/ISAAC (J-, H-, and Ks-bands), and four Spitzer/IRAC channels (3.6, 4.5, 5.8, and 8.0 micron). The catalog is selected in the z-band (F850LP) and photometry in each band is carried out using the recently completed TFIT algorithm, which performs PSF matched photometry uniformly across different instruments and filters, despite large variations in PSFs and pixel scales. Photometric redshifts are derived using the GOODZ code, which is based on the template fitting method using priors. The code also implements "training" of the template SED set, using available spectroscopic redshifts in order to minimize systematic differences between the templates and the SEDs of the observed galaxies. Our final catalog covers an area of 153 sq. arcmin and includes photometric redshifts for a total of 32,505 objects. The scatter between our estimated photometric and spectroscopic redshifts is sigma=0.040 with 3.7% outliers to the full z-band depth of our catalog, decreasing to sigma=0.039 and 2.1% outliers at a magnitude limit m(z)<24.5. This is consistent with the best results previously published for GOODS-S galaxies, however, the present catalog is the deepest yet available and provides photometric redshifts for significantly more objects to deeper flux limits and higher redshifts than earlier works. Furthermore, we show that the photometric redshifts estimated here for galaxies selected as dropouts are consistent with those expected based on the Lyman break technique.

We present optical spectroscopic follow-up of a sample of Distant Red Galaxies (DRGs) with K < 22.5 (Vega), selected by J-K > 2.3, in the Hubble Deep Field South, the MS 1054-03 field, and the Chandra Deep Field South. Spectroscopic redshifts were obtained for 15 DRGs. Only 2 out of 15 DRGs are located at z < 2, suggesting a high efficiency to select high-redshift sources. From other spectroscopic surveys in the CDFS targeting intermediate to high redshift populations selected with different criteria, we find spectroscopic redshifts for a further 30 DRGs. We use the sample of spectroscopically confirmed DRGs to establish the high quality (scatter in \Delta z/(1+z) of ~ 0.05) of their photometric redshifts in the considered deep fields, as derived with EAZY (Brammer et al. 2008). Combining the spectroscopic and photometric redshifts, we find that 74% of DRGs with K < 22.5 lie at z > 2. The combined spectroscopic and photometric sample is used to analyze the distinct intrinsic and observed properties of DRGs at z < 2 and z > 2. In our photometric sample to K < 22.5, low-redshift DRGs are brighter in K than high-redshift DRGs by 0.7 mag, and more extincted by 1.2 mag in Av. Our analysis shows that the DRG criterion selects galaxies with different properties at different redshifts. Such biases can be largely avoided by selecting galaxies based on their rest-frame properties, which requires very good multi-band photometry and high quality photometric redshifts.

We use the deepest and most complete redshift catalog currently available (the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data) to minimize residuals between photometric and spectroscopic redshift estimates. The good agreement at z_spec < 1.5 shows that model libraries provide a good description of the galaxy population. At z_spec > 2.0, the systematic shift between photometric and spectroscopic redshifts decreases when the modeling of the absorption by the interstellar and intergalactic media is refined. As a result, in the entire redshift range 0 < z < 6, residuals between photometric and spectroscopic redshifts are roughly halved. For objects fainter than the spectroscopic limit, the main source of uncertainty in photometric redshifts is related to photometric errors, and can be assessed with Monte Carlo simulations.

We present photometric redshifts for the COSMOS survey derived from a new code, optimized to yield accurate and reliable redshifts and spectral types of galaxies down to faint magnitudes and redshifts out to z ~ 1.2. The technique uses χ^2 template fitting, combined with luminosity function priors and with the option to estimate the internal extinction [or E(B - V)]. The median most probable redshift, best-fit spectral type and reddening, absolute magnitude, and stellar mass are derived in addition to the full redshift probability distributions. Using simulations with sampling and noise similar to those in COSMOS, the accuracy and reliability is estimated for the photometric redshifts as a function of the magnitude limits of the sample, S/N ratios, and the number of bands used. We find from the simulations that the ratio of derived 95% confidence interval in the χ^2 probability distribution to the estimated photometric redshift (D_(95)) can be used to identify and exclude the catastrophic failures in the photometric redshift estimates. To evaluate the reliability of the photometric redshifts, we compare the derived redshifts with high-reliability spectroscopic redshifts for a sample of 868 normal galaxies with z &lt; 1.2 from zCOSMOS. Considering different scenarios, depending on using prior, no prior, and/or extinction, we compare the photometric and spectroscopic redshifts for this sample. The rms scatter between the estimated photometric redshifts and known spectroscopic redshifts is σ(Δ(z)) = 0.031, where Δ(z) = (z_(phot) - z_(spec))/(1 + z_(spec)) with a small fraction of outliers (&lt;2.5%) [outliers are defined as objects with Δ(z) &gt; 3σ(Δ(z)), where σ(Δ(z)) is the rms scatter in Δ(z)]. We also find good agreement [σ(Δ(z)) = 0.10] between photometric and spectroscopic redshifts for type II AGNs. We compare results from our photometric redshift procedure with three other independent codes and find them in excellent agreement. We show preliminary results, based on photometric redshifts for the entire COSMOS sample (to i &lt; 25 mag).&#13;\n

We present 101- and 151-GHz ALMA continuum images for 85 fields selected from Herschel observations that have 500-μm flux densities &amp;gt;80 mJy and 250–500-μm colours consistent with z &amp;gt; 2, most of which are expected to be gravitationally lensed or hyperluminous infrared galaxies. Approximately half of the Herschel 500-μm sources were resolved into multiple ALMA sources, but 11 of the 15 brightest 500-μm Herschel sources correspond to individual ALMA sources. For the 37 fields containing either a single source with a spectroscopic redshift or two sources with the same spectroscopic redshift, we examined the colour temperatures and dust emissivity indices. The colour temperatures only vary weakly with redshift and are statistically consistent with no redshift-dependent temperature variations, which generally corresponds to results from other samples selected in far-infrared, submillimetre, or millimetre bands but not to results from samples selected in optical or near-infrared bands. The dust emissivity indices, with very few exceptions, are largely consistent with a value of 2. We also compared spectroscopic redshifts to photometric redshifts based on spectral energy distribution templates designed for infrared-bright high-redshift galaxies. While the templates systematically underestimate the redshifts by ∼15 per cent, the inclusion of ALMA data decreases the scatter in the predicted redshifts by a factor of ∼2, illustrating the potential usefulness of these millimetre data for estimating photometric redshifts.

Ultracool dwarfs (UCDs) encompass a wide variety of compact stellar-like objects with spectra classified as late-M, L, T, and Y. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology designed to discover and characterize UCDs in deep extragalactic surveys like Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) and Cosmological Evolution Survey (COSMOS). Three complimentary searches based on parallaxes, proper motions and colours, respectively, were carried out. A total of 897 candidate UCDs were found, with only 16 previously reported in SIMBAD. Most of the new UCDs reported here are likely late-M and L dwarfs because of the limitations imposed by the utilization of optical (Gaia DR2 and r-band) data. We complement ALHAMBRA and COSMOS photometry with other catalogues in the optical and infrared using VOSA, a VO tool that estimates effective temperatures from the spectral energy distribution fitting to collections of theoretical models. The agreement between the number of UCDs found in the COSMOS field and theoretical estimations together with the low false-negative rate (known UCDs not discovered in our search) validates the methodology proposed in this work, which will be used in the forthcoming wide and deep surveys provided by the Euclid space mission. Simulations of Euclid number counts for UCDs detectable in different photometric passbands are presented for a wide survey area of 15 000 deg2, and the limitations of applicability of Euclid data to detect UCDs using the methods employed in this paper are discussed.

We present strong evidence for the existence of a supercluster at a redshift of z=0.54 in the direction of Selected Area 68. From the distribution of galaxies with spectroscopic redshifts we find that there is a large over-density of galaxies (a factor of four over the number expected in an unclustered universe) within the redshift range 0.530 < z < 0.555. By considering the spatial distribution of galaxies within this redshift range (using spectroscopic and photometric redshifts) we show that the galaxies in SA68 form a linear structure passing from the South-West of the survey field through to the North-East (with a position angle of approximately 35 deg East of North). This position angle is coincident with the positions of the X-ray clusters CL0016+16, RX J0018.3+1618 and a new X-ray cluster, RX J0018.8+1602, centered near the radio source 54W084. All three of these sources are at a redshift of approximately z=0.54 and have position angles, derived from their X-ray photon distributions, consistent with that measured for the supercluster. Assuming a redshift of 0.54 for the distribution of galaxies and a FWHM dispersion in redshift of 0.020 this represents a coherent structure with a radial extent of 31 Mpc, transverse dimension of 12 Mpc, and a thickness of approximately 4 Mpc. The detection of this possible supercluster demonstrates the power of using X-ray observations, combined with multicolor observations, to map the large scale distribution of galaxies at intermediate redshifts.

Infrared 3.6 to 8 micron images of the Extended Groth Strip yield plausible counterpart identifications for all but one of 510 radio sources in the AEGIS20 S(1.4 GHz) > 50 micro-Jy sample. This is the first such deep sample that has been effectively 100% identified. Achieving the same identification rate at R-band would require observations reaching R_AB > 27. Spectroscopic redshifts are available for 46% of the sample and photometric redshifts for an additional 47%. Almost all of the sources with 3.6 micron AB magnitudes brighter than 19 have spectroscopic redshifts z < 1.1, while fainter objects predominantly have photometric redshifts with 1 \lapprox z \lapprox 3. Unlike more powerful radio sources that are hosted by galaxies having large stellar masses within a relatively narrow range, the AEGIS20 counterparts have stellar masses spanning more than a factor of 10 at z \sim 1. The sources are roughly 10--15% starbursts at z \lapprox 0.5 and 20--25% AGNs mostly at z > 1 with the remainder of uncertain nature.

Context. Redshifts are fundamental for our understanding of extragalactic X-ray sources. Ambiguous counterpart associations, expensive optical spectroscopy, and/or multimission multiwavelength coverage to resolve degeneracies often make estimation difficult in practice.Aims. We attempt to constrain redshifts of obscured active galactic nuclei (AGN) using only low-resolution X-ray spectra.Methods. Our method for determining redshifts from the X-ray spectrum (XZ) fits AGN X-ray spectra with a moderately complex spectral model incorporating a corona, a torus obscurer, and a warm mirror. Using the Bayesian X-ray Astronomy (BXA) package, we constrain redshift, column density, photon index, and luminosity simultaneously. The redshift information primarily comes from absorption edges in Compton-thin AGN, and from the Fe Kαfluorescent line in heavily obscured AGN. A new generic background fitting method allows us to extract more information from limited numbers of source counts.Results. We derive redshift constraints for 74/321 hard-band detected sources in theChandradeep field South. Comparing with spectroscopic redshifts, we find an outlier fraction of 8%, indicating that our model assumptions are valid. For threeChandradeep fields, we release our XZ redshift estimates.Conclusions. The independent XZ estimate is easy to apply and effective for a large fraction of obscured AGN in today’s deep surveys without the need for any additional data. Compared to different redshift estimation methods, XZ can resolve degeneracies in photometric redshifts, help detect potential association problems, and confirm uncertain single-line spectroscopic redshifts. With high spectral resolution and a large collecting area, this technique will be highly effective forAthena/WFI observations.

We describe the far-infrared (far-IR; rest-frame 8–1000-μm) properties of a sample of 443 Hα-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select Hα (and [O ii] if available) emitters in a narrow redshift slice at z = 1.47 ± 0.02. We use a stacking approach in Spitzer-MIPS mid-IR, Herschel-PACS/SPIRE far-IR [from the PACS Evolutionary Prove (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES)] and AzTEC mm-wave images to describe their typical far-IR properties. We find that HiZELS galaxies with observed Hα luminosities of L(Hα)obs ≈ 108.1-9.1 L⊙ ( ≈ 1041.7-42.7 erg s−1) have bolometric far-IR luminosities of typical luminous IR galaxies, |$L(8{\rm -}1000\,\mu {\rm m})\approx 10^{11.41^{+0.04}_{-0.06}} $| L⊙. Combining the Hα and far-IR luminosities, we derive median star formation rates (SFRs) of SFRHα, FIR = 32 ± 5 M⊙ yr−1 and Hα extinctions of AHα = 1.0 ± 0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M*) to AHα relations and the little or no evolution up to z = 1.47. For HiZELS galaxies (or similar samples) we provide an empirical parametrization of the SFR as a function of rest-frame (u − z) colours and 3.6-μm photometry – a useful proxy to aid in the absence of far-IR detections in high-z galaxies. We find that the observed Hα luminosity is a dominant SFR tracer when rest-frame (u − z) colours are ≲0.9 mag or when Spitzer-3.6-μm photometry is fainter than 22 mag (Vega) or when stellar masses are lower than 109.7 M⊙. We do not find any correlation between the [O ii]/Hα and far-IR luminosity, suggesting that this emission line ratio does not trace the extinction of the most obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly.