How well does the Friends-of-Friends algorithm recover group properties from galaxy catalogues limited in both distance and luminosity?

NASA Astrophysics Data System (ADS)

Duarte, Manuel; Mamon, Gary A.

2014-05-01

The specific star formation rates of galaxies are influenced both by their mass and by their environment. Moreover, the mass function of groups and clusters serves as a powerful cosmological tool. It is thus important to quantify the accuracy to which group properties are extracted from redshift surveys. We test here the Friends-of-Friends (FoF) grouping algorithm, which depends on two linking lengths (LLs), plane-of-sky and line-of-sight (LOS), normalized to the mean nearest neighbour separation of field galaxies. We argue, on theoretical grounds, that LLs should be b⊥ ≃ 0.11, and b∥ ≈ 1.3 to recover 95 per cent of all galaxies with projected radii within the virial radius r200 and 95 per cent of the galaxies along the LOS. We then predict that 80 to 90 per cent of the galaxies in FoF groups should lie within their parent real-space groups (RSGs), defined within their virial spheres. We test the FoF extraction for 16 × 16 pairs of LLs, using subsamples of galaxies, doubly complete in distance and luminosity, of a flux-limited mock Sloan Digital Sky Survey (SDSS) galaxy catalogue. We find that massive RSGs are more prone to fragmentation, while the fragments typically have low estimated mass, with typically 30 per cent of groups of low and intermediate estimated mass being fragments. Group merging rises drastically with estimated mass. For groups of three or more galaxies, galaxy completeness and reliability are both typically better than 80 per cent (after discarding the fragments). Estimated masses of extracted groups are biased low, by up to a factor 4 at low richness, while the inefficiency of mass estimation improves from 0.85 dex to 0.2 dex when moving from low to high multiplicity groups. The optimal LLs depend on the scientific goal for the group catalogue. We propose b⊥ ≃ 0.07, with b∥ ≃ 1.1 for studies of environmental effects, b∥ ≃ 2.5 for cosmographic studies and b∥ ≃ 5 for followups of individual groups.

The MICE Grand Challenge lightcone simulation - II. Halo and galaxy catalogues

NASA Astrophysics Data System (ADS)

Crocce, M.; Castander, F. J.; Gaztañaga, E.; Fosalba, P.; Carretero, J.

2015-10-01

This is the second in a series of three papers in which we present an end-to-end simulation from the MICE collaboration, the MICE Grand Challenge (MICE-GC) run. The N-body contains about 70 billion dark-matter particles in a (3 h-1 Gpc)3 comoving volume spanning five orders of magnitude in dynamical range. Here, we introduce the halo and galaxy catalogues built upon it, both in a wide (5000 deg2) and deep (z < 1.4) lightcone and in several comoving snapshots. Haloes were resolved down to few 1011 h-1 M⊙. This allowed us to model galaxies down to absolute magnitude Mr < -18.9. We used a new hybrid halo occupation distribution and abundance matching technique for galaxy assignment. The catalogue includes the spectral energy distributions of all galaxies. We describe a variety of halo and galaxy clustering applications. We discuss how mass resolution effects can bias the large-scale two-pt clustering amplitude of poorly resolved haloes at the ≲5 per cent level, and their three-pt correlation function. We find a characteristic scale-dependent bias of ≲6 per cent across the BAO feature for haloes well above M⋆ ˜ 1012 h-1 M⊙ and for luminous red galaxy like galaxies. For haloes well below M⋆ the scale dependence at 100 h-1 Mpc is ≲2 per cent. Lastly, we discuss the validity of the large-scale Kaiser limit across redshift and departures from it towards non-linear scales. We make the current version of the lightcone halo and galaxy catalogue (MICECATv1.0) publicly available through a dedicated web portal to help develop and exploit the new generation of astronomical surveys.

The Galaxy Cluster Merger Catalog: An Online Repository of Mock Observations from Simulated Galaxy Cluster Mergers

NASA Astrophysics Data System (ADS)

ZuHone, J. A.; Kowalik, K.; Öhman, E.; Lau, E.; Nagai, D.

2018-01-01

We present the “Galaxy Cluster Merger Catalog.” This catalog provides an extensive suite of mock observations and related data for N-body and hydrodynamical simulations of galaxy cluster mergers and clusters from cosmological simulations. These mock observations consist of projections of a number of important observable quantities in several different wavebands, as well as along different lines of sight through each simulation domain. The web interface to the catalog consists of easily browsable images over epoch and projection direction, as well as download links for the raw data and a JS9 interface for interactive data exploration. The data are presented within a consistent format so that comparison between simulations is straightforward. All of the data products are provided in the standard Flexible Image Transport System file format. The data are being stored on the yt Hub (http://hub.yt), which allows for remote access and analysis using a Jupyter notebook server. Future versions of the catalog will include simulations from a number of research groups and a variety of research topics related to the study of interactions of galaxy clusters with each other and with their member galaxies. The catalog is located at http://gcmc.hub.yt.

Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes

NASA Astrophysics Data System (ADS)

Masaki, Shogo; Hikage, Chiaki; Takada, Masahiro; Spergel, David N.; Sugiyama, Naoshi

2013-08-01

We develop a novel abundance matching method to construct a mock catalogue of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogues of haloes and subhaloes in N-body simulations for a Λ-dominated cold dark matter model. Motivated by observations suggesting that LRGs are passively evolving, massive early-type galaxies with a typical age ≳5 Gyr, we assume that simulated haloes at z = 2 (z2-halo) are progenitors for LRG-host subhaloes observed today, and we label the most tightly bound particles in each progenitor z2-halo as LRG `stars'. We then identify the subhaloes containing these stars to z = 0.3 (SDSS redshift) in descending order of the masses of z2-haloes until the comoving number density of the matched subhaloes becomes comparable to the measured number density of SDSS LRGs, bar{n}_LRG=10^{-4} h^3 Mpc^{-3}. Once the above prescription is determined, our only free parameter is the number density of haloes identified at z = 2 and this parameter is fixed to match the observed number density at z = 0.3. By tracing subsequent merging and assembly histories of each progenitor z2-halo, we can directly compute, from the mock catalogue, the distributions of central and satellite LRGs and their internal motions in each host halo at z = 0.3. While the SDSS LRGs are galaxies selected by the magnitude and colour cuts from the SDSS images and are not necessarily a stellar-mass-selected sample, our mock catalogue reproduces a host of SDSS measurements: the halo occupation distribution for central and satellite LRGs, the projected autocorrelation function of LRGs, the cross-correlation of LRGs with shapes of background galaxies (LRG-galaxy weak lensing) and the non-linear redshift-space distortion effect, the Finger-of-God effect, in the angle-averaged redshift-space power spectrum. The mock catalogue generated based on our method can be used for removing or calibrating systematic errors in the cosmological interpretation of LRG clustering

Generating log-normal mock catalog of galaxies in redshift space

NASA Astrophysics Data System (ADS)

Agrawal, Aniket; Makiya, Ryu; Chiang, Chi-Ting; Jeong, Donghui; Saito, Shun; Komatsu, Eiichiro

2017-10-01

We present a public code to generate a mock galaxy catalog in redshift space assuming a log-normal probability density function (PDF) of galaxy and matter density fields. We draw galaxies by Poisson-sampling the log-normal field, and calculate the velocity field from the linearised continuity equation of matter fields, assuming zero vorticity. This procedure yields a PDF of the pairwise velocity fields that is qualitatively similar to that of N-body simulations. We check fidelity of the catalog, showing that the measured two-point correlation function and power spectrum in real space agree with the input precisely. We find that a linear bias relation in the power spectrum does not guarantee a linear bias relation in the density contrasts, leading to a cross-correlation coefficient of matter and galaxies deviating from unity on small scales. We also find that linearising the Jacobian of the real-to-redshift space mapping provides a poor model for the two-point statistics in redshift space. That is, non-linear redshift-space distortion is dominated by non-linearity in the Jacobian. The power spectrum in redshift space shows a damping on small scales that is qualitatively similar to that of the well-known Fingers-of-God (FoG) effect due to random velocities, except that the log-normal mock does not include random velocities. This damping is a consequence of non-linearity in the Jacobian, and thus attributing the damping of the power spectrum solely to FoG, as commonly done in the literature, is misleading.

Generating log-normal mock catalog of galaxies in redshift space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, Aniket; Makiya, Ryu; Saito, Shun

We present a public code to generate a mock galaxy catalog in redshift space assuming a log-normal probability density function (PDF) of galaxy and matter density fields. We draw galaxies by Poisson-sampling the log-normal field, and calculate the velocity field from the linearised continuity equation of matter fields, assuming zero vorticity. This procedure yields a PDF of the pairwise velocity fields that is qualitatively similar to that of N-body simulations. We check fidelity of the catalog, showing that the measured two-point correlation function and power spectrum in real space agree with the input precisely. We find that a linear biasmore » relation in the power spectrum does not guarantee a linear bias relation in the density contrasts, leading to a cross-correlation coefficient of matter and galaxies deviating from unity on small scales. We also find that linearising the Jacobian of the real-to-redshift space mapping provides a poor model for the two-point statistics in redshift space. That is, non-linear redshift-space distortion is dominated by non-linearity in the Jacobian. The power spectrum in redshift space shows a damping on small scales that is qualitatively similar to that of the well-known Fingers-of-God (FoG) effect due to random velocities, except that the log-normal mock does not include random velocities. This damping is a consequence of non-linearity in the Jacobian, and thus attributing the damping of the power spectrum solely to FoG, as commonly done in the literature, is misleading.« less

Combining Statistical Samples of Resolved-ISM Simulated Galaxies with Realistic Mock Observations to Fully Interpret HST and JWST Surveys

NASA Astrophysics Data System (ADS)

Faucher-Giguere, Claude-Andre

2016-10-01

HST has invested thousands of orbits to complete multi-wavelength surveys of high-redshift galaxies including the Deep Fields, COSMOS, 3D-HST and CANDELS. Over the next few years, JWST will undertake complementary, spatially-resolved infrared observations. Cosmological simulations are the most powerful tool to make detailed predictions for the properties of galaxy populations and to interpret these surveys. We will leverage recent major advances in the predictive power of cosmological hydrodynamic simulations to produce the first statistical sample of hundreds of galaxies simulated with 10 pc resolution and with explicit interstellar medium and stellar feedback physics proved to simultaneously reproduce the galaxy stellar mass function, the chemical enrichment of galaxies, and the neutral hydrogen content of galaxy halos. We will process our new set of full-volume cosmological simulations, called FIREBOX, with a mock imaging and spectral synthesis pipeline to produce realistic mock HST and JWST observations, including spatially-resolved photometry and spectroscopy. By comparing FIREBOX with recent high-redshift HST surveys, we will study the stellar build up of galaxies, the evolution massive star-forming clumps, their contribution to bulge growth, the connection of bulges to star formation quenching, and the triggering mechanisms of AGN activity. Our mock data products will also enable us to plan future JWST observing programs. We will publicly release all our mock data products to enable HST and JWST science beyond our own analysis, including with the Frontier Fields.

Machine-learning identification of galaxies in the WISE × SuperCOSMOS all-sky catalogue

NASA Astrophysics Data System (ADS)

Krakowski, T.; Małek, K.; Bilicki, M.; Pollo, A.; Kurcz, A.; Krupa, M.

2016-11-01

Context. The two currently largest all-sky photometric datasets, WISE and SuperCOSMOS, have been recently cross-matched to construct a novel photometric redshift catalogue on 70% of the sky. Galaxies were separated from stars and quasars through colour cuts, which may leave imperfections because different source types may overlap in colour space. Aims: The aim of the present work is to identify galaxies in the WISE × SuperCOSMOS catalogue through an alternative approach of machine learning. This allows us to define more complex separations in the multi-colour space than is possible with simple colour cuts, and should provide a more reliable source classification. Methods: For the automatised classification we used the support vector machines (SVM) learning algorithm and employed SDSS spectroscopic sources that we cross-matched with WISE × SuperCOSMOS to construct the training and verification set. We performed a number of tests to examine the behaviour of the classifier (completeness, purity, and accuracy) as a function of source apparent magnitude and Galactic latitude. We then applied the classifier to the full-sky data and analysed the resulting catalogue of candidate galaxies. We also compared the resulting dataset with the one obtained through colour cuts. Results: The tests indicate very high accuracy, completeness, and purity (>95%) of the classifier at the bright end; this deteriorates for the faintest sources, but still retains acceptable levels of 85%. No significant variation in the classification quality with Galactic latitude is observed. When we applied the classifier to all-sky WISE × SuperCOSMOS data, we found 15 million galaxies after masking problematic areas. The resulting sample is purer than the one produced by applying colour cuts, at the price of a lower completeness across the sky. Conclusions: The automatic classification is a successful alternative approach to colour cuts for defining a reliable galaxy sample. The identifications we

Catalogue of UV sources in the Galaxy

NASA Astrophysics Data System (ADS)

Beitia-Antero, L.; Gómez de Castro, A. I.

2017-03-01

The Galaxy Evolution Explorer (GALEX) ultraviolet (UV) database contains the largest photometric catalogue in the ultraviolet range; as a result GALEX photometric bands, Near UV band (NUV) and the Far UV band (FUV), have become standards. Nevertheless, the GALEX catalogue does not include bright UV sources due to the high sensitivity of its detectors, neither sources in the Galactic plane. In order to extend the GALEX database for future UV missions, we have obtained synthetic FUV and NUV photometry using the database of UV spectra generated by the International Ultraviolet Explorer (IUE). This database contains 63,755 spectra in the low dispersion mode (λ / δ λ ˜ 300) obtained during its 18-year lifetime. For stellar sources in the IUE database, we have selected spectra with high Signal-To-NoiseRatio (SNR) and computed FUV and NUV magnitudes using the GALEX transmission curves along with the conversion equations between flux and magnitudes provided by the mission. Besides, we have performed variability tests to determine whether the sources were variable (during the IUE observations). As a result, we have generated two different catalogues: one for non-variable stars and another one for variable sources. The former contains FUV and NUV magnitudes, while the latter gives the basic information and the FUV magnitude for each observation. The consistency of the magnitudes has been tested using White Dwarfs contained in both GALEX and IUE samples. The catalogues are available through the Centre des Donées Stellaires. The sources are distributed throughout the whole sky, with a special coverage of the Galactic plane.

Remapping dark matter halo catalogues between cosmological simulations

NASA Astrophysics Data System (ADS)

Mead, A. J.; Peacock, J. A.

2014-05-01

We present and test a method for modifying the catalogue of dark matter haloes produced from a given cosmological simulation, so that it resembles the result of a simulation with an entirely different set of parameters. This extends the method of Angulo & White, which rescales the full particle distribution from a simulation. Working directly with the halo catalogue offers an advantage in speed, and also allows modifications of the internal structure of the haloes to account for non-linear differences between cosmologies. Our method can be used directly on a halo catalogue in a self-contained manner without any additional information about the overall density field; although the large-scale displacement field is required by the method, this can be inferred from the halo catalogue alone. We show proof of concept of our method by rescaling a matter-only simulation with no baryon acoustic oscillation (BAO) features to a more standard Λ cold dark matter model containing a cosmological constant and a BAO signal. In conjunction with the halo occupation approach, this method provides a basis for the rapid generation of mock galaxy samples spanning a wide range of cosmological parameters.

SDSS-III Baryon Oscillation Spectroscopic Survey data release 12: Galaxy target selection and large-scale structure catalogues

DOE PAGES

Reid, Beth; Ho, Shirley; Padmanabhan, Nikhil; ...

2015-11-17

The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target catalogue caused by changes either in the targeting algorithm or properties of the data used, the pattern of spectroscopic observations, the spatial distribution of targets formore » which redshifts were not obtained, and variations in the target sky density due to observational systematics. We document here the target selection algorithms used to create the galaxy samples that comprise BOSS. We also present the algorithms used to create large-scale structure catalogues for the final Data Release (DR12) samples and the associated random catalogues that quantify the survey mask. The algorithms are an evolution of those used by the BOSS team to construct catalogues from earlier data, and have been designed to accurately quantify the galaxy sample. Furthermore, the code used, designated mksample, is released with this paper.« less

GLADE: A Galaxy Catalogue for Multi-Messenger Searches in the Advanced Gravitational-Wave Detector Era

NASA Astrophysics Data System (ADS)

Dálya, G.; Galgóczi, G.; Dobos, L.; Frei, Z.; Heng, I. S.; Macas, R.; Messenger, C.; Raffai, P.; de Souza, R. S.

2018-06-01

We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localised electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA and SDSS-DR12Q. GLADE is complete up to d_L=37^{+3}_{-4} Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance dL, and contains all of the brightest galaxies giving half of the total B-band luminosity up to dL = 91 Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local universe.

Extracting cosmological information from the angular power spectrum of the 2MASS Photometric Redshift catalogue

NASA Astrophysics Data System (ADS)

Balaguera-Antolínez, A.; Bilicki, M.; Branchini, E.; Postiglione, A.

2018-05-01

Using the almost all-sky 2MASS Photometric Redshift catalogue (2MPZ) we perform for the first time a tomographic analysis of galaxy angular clustering in the local Universe (z < 0.24). We estimate the angular auto- and cross-power spectra of 2MPZ galaxies in three photometric redshift bins, and use dedicated mock catalogues to assess their errors. We measure a subset of cosmological parameters, having fixed the others at their Planck values, namely the baryon fraction fb=0.14^{+0.09}_{-0.06}, the total matter density parameter Ωm = 0.30 ± 0.06, and the effective linear bias of 2MPZ galaxies beff, which grows from 1.1^{+0.3}_{-0.4} at = 0.05 up to 2.1^{+0.3}_{-0.5} at = 0.2, largely because of the flux-limited nature of the data set. The results obtained here for the local Universe agree with those derived with the same methodology at higher redshifts, and confirm the importance of the tomographic technique for next-generation photometric surveys such as Euclid or Large Synoptic Survey Telescope.

The Large Local Hole in the Galaxy Distribution: The 2MASS Galaxy Angular Power Spectrum

NASA Astrophysics Data System (ADS)

Frith, W. J.; Outram, P. J.; Shanks, T.

2005-06-01

We present new evidence for a large deficiency in the local galaxy distribution situated in the ˜4000 deg2 APM survey area. We use models guided by the 2dF Galaxy Redshift Survey (2dFGRS) n(z) as a probe of the underlying large-scale structure. We first check the usefulness of this technique by comparing the 2dFGRS n(z) model prediction with the K-band and B-band number counts extracted from the 2MASS and 2dFGRS parent catalogues over the 2dFGRS Northern and Southern declination strips, before turning to a comparison with the APM counts. We find that the APM counts in both the B and K-bands indicate a deficiency in the local galaxy distribution of ˜30% to z ≈ 0.1 over the entire APM survey area. We examine the implied significance of such a large local hole, considering several possible forms for the real-space correlation function. We find that such a deficiency in the APM survey area indicates an excess of power at large scales over what is expected from the correlation function observed in 2dFGRS correlation function or predicted from ΛCDM Hubble Volume mock catalogues. In order to check further the clustering at large scales in the 2MASS data, we have calculated the angular power spectrum for 2MASS galaxies. Although in the linear regime (l<30), ΛCDM models can give a good fit to the 2MASS angular power spectrum, over a wider range (l<100) the power spectrum from Hubble Volume mock catalogues suggests that scale-dependent bias may be needed for ΛCDM to fit. However, the modest increase in large-scale power observed in the 2MASS angular power spectrum is still not enough to explain the local hole. If the APM survey area really is 25% deficient in galaxies out to z≈0.1, explanations for the disagreement with observed galaxy clustering statistics include the possibilities that the galaxy clustering is non-Gaussian on large scales or that the 2MASS volume is still too small to represent a `fair sample' of the Universe. Extending the 2dFGRS redshift survey

Populating dark matter haloes with galaxies: comparing the 2dFGRS with mock galaxy redshift surveys

NASA Astrophysics Data System (ADS)

Yang, Xiaohu; Mo, H. J.; Jing, Y. P.; van den Bosch, Frank C.; Chu, YaoQuan

2004-06-01

In two recent papers, we developed a powerful technique to link the distribution of galaxies to that of dark matter haloes by considering halo occupation numbers as a function of galaxy luminosity and type. In this paper we use these distribution functions to populate dark matter haloes in high-resolution N-body simulations of the standard ΛCDM cosmology with Ωm= 0.3, ΩΛ= 0.7 and σ8= 0.9. Stacking simulation boxes of 100 h-1 Mpc and 300 h-1 Mpc with 5123 particles each we construct mock galaxy redshift surveys out to a redshift of z= 0.2 with a numerical resolution that guarantees completeness down to 0.01L*. We use these mock surveys to investigate various clustering statistics. The predicted two-dimensional correlation function ξ(rp, π) reveals clear signatures of redshift space distortions. The projected correlation functions for galaxies with different luminosities and types, derived from ξ(rp, π), match the observations well on scales larger than ~3 h-1 Mpc. On smaller scales, however, the model overpredicts the clustering power by about a factor two. Modelling the `finger-of-God' effect on small scales reveals that the standard ΛCDM model predicts pairwise velocity dispersions (PVD) that are ~400 km s-1 too high at projected pair separations of ~1 h-1 Mpc. A strong velocity bias in massive haloes, with bvel≡σgal/σdm~ 0.6 (where σgal and σdm are the velocity dispersions of galaxies and dark matter particles, respectively) can reduce the predicted PVD to the observed level, but does not help to resolve the overprediction of clustering power on small scales. Consistent results can be obtained within the standard ΛCDM model only when the average mass-to-light ratio of clusters is of the order of 1000 (M/L)solar in the B-band. Alternatively, as we show by a simple approximation, a ΛCDM model with σ8~= 0.75 may also reproduce the observational results. We discuss our results in light of the recent WMAP results and the constraints on σ8 obtained

NIR Tully-Fisher in the Zone of Avoidance - III. Deep NIR catalogue of the HIZOA galaxies

NASA Astrophysics Data System (ADS)

Said, Khaled; Kraan-Korteweg, Renée C.; Jarrett, T. H.; Staveley-Smith, Lister; Williams, Wendy L.

2016-11-01

We present a deep near-infrared (NIR; J, H, and Ks bands) photometric catalogue of sources from the Parkes H I Zone of Avoidance (HIZOA) survey, which forms the basis for an investigation of the matter distribution in the Zone of Avoidance. Observations were conducted between 2006 and 2013 using the Infrared Survey Facility (IRSF), a 1.4-m telescope situated at the South African Astronomical Observatory site in Sutherland. The images cover all 1108 HIZOA detections and yield 915 galaxies. An additional 105 bright 2MASS galaxies in the southern ZOA were imaged with the IRSF, resulting in 129 galaxies. The average Ks-band seeing and sky background for the survey are 1.38 arcsec and 20.1 mag, respectively. The detection rate as a function of stellar density and dust extinction is found to depend mainly on the H I mass of the H I detected galaxies, which in principal correlates with the NIR brightness of the spiral galaxies. The measured isophotal magnitudes are of sufficient accuracy (errors ˜0.02 mag) to be used in a Tully-Fisher analysis. In the final NIR catalogue, 285 galaxies have both IRSF and 2MASS photometry (180 HIZOA plus 105 bright 2MASX galaxies). The Ks-band isophotal magnitudes presented in this paper agree, within the uncertainties, with those reported in the 2MASX catalogue. Another 30 galaxies, from the HIZOA northern extension, are also covered by UKIDSS Galactic Plane Survey (GPS) images, which are one magnitude deeper than our IRSF images. A modified version of our photometry pipeline was used to derive the photometric parameters of these UKIDSS galaxies. Good agreement was found between the respective Ks-band isophotal magnitudes. These comparisons confirm the robustness of the isophotal parameters and demonstrate that the IRSF images do not suffer from foreground contamination, after star removal, nor underestimate the isophotal fluxes of ZoA galaxies.

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmic flows and cosmic web from luminous red galaxies

NASA Astrophysics Data System (ADS)

Ata, Metin; Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E.; Ferraro, Simone; Gil-Marín, Hector; McDonald, Patrick; Hernández Monteagudo, Carlos; Müller, Volker; Yepes, Gustavo; Autefage, Mathieu; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R.; Burden, Angela; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; McBride, Cameron; Neyrinck, Mark; Olmstead, Matthew D.; Padmanabhan, Nikhil; Percival, Will J.; Prada, Francisco; Rossi, Graziano; Sánchez, Ariel G.; Schlegel, David; Schneider, Donald P.; Seo, Hee-Jong; Streblyanska, Alina; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana

2017-06-01

We present a Bayesian phase-space reconstruction of the cosmic large-scale matter density and velocity fields from the Sloan Digital Sky Survey-III Baryon Oscillations Spectroscopic Survey Data Release 12 CMASS galaxy clustering catalogue. We rely on a given Λ cold dark matter cosmology, a mesh resolution in the range of 6-10 h-1 Mpc, and a lognormal-Poisson model with a redshift-dependent non-linear bias. The bias parameters are derived from the data and a general renormalized perturbation theory approach. We use combined Gibbs and Hamiltonian sampling, implemented in the argo code, to iteratively reconstruct the dark matter density field and the coherent peculiar velocities of individual galaxies, correcting hereby for coherent redshift space distortions. Our tests relying on accurate N-body-based mock galaxy catalogues show unbiased real space power spectra of the non-linear density field up to k ˜ 0.2 h Mpc-1, and vanishing quadrupoles down to r ˜ 20 h-1 Mpc. We also demonstrate that the non-linear cosmic web can be obtained from the tidal field tensor based on the Gaussian component of the reconstructed density field. We find that the reconstructed velocities have a statistical correlation coefficient compared to the true velocities of each individual light-cone mock galaxy of r ˜ 0.68 including about 10 per cent of satellite galaxies with virial motions (about r = 0.75 without satellites). The power spectra of the velocity divergence agree well with theoretical predictions up to k ˜ 0.2 h Mpc-1. This work will be especially useful to improve, for example, baryon acoustic oscillation reconstructions, kinematic Sunyaev-Zeldovich, integrated Sachs-Wolfe measurements or environmental studies.

Weak lensing calibration of mass bias in the REFLEX+BCS X-ray galaxy cluster catalogue

NASA Astrophysics Data System (ADS)

Simet, Melanie; Battaglia, Nicholas; Mandelbaum, Rachel; Seljak, Uroš

2017-04-01

The use of large, X-ray-selected Galaxy cluster catalogues for cosmological analyses requires a thorough understanding of the X-ray mass estimates. Weak gravitational lensing is an ideal method to shed light on such issues, due to its insensitivity to the cluster dynamical state. We perform a weak lensing calibration of 166 galaxy clusters from the REFLEX and BCS cluster catalogue and compare our results to the X-ray masses based on scaled luminosities from that catalogue. To interpret the weak lensing signal in terms of cluster masses, we compare the lensing signal to simple theoretical Navarro-Frenk-White models and to simulated cluster lensing profiles, including complications such as cluster substructure, projected large-scale structure and Eddington bias. We find evidence of underestimation in the X-ray masses, as expected, with = 0.75 ± 0.07 stat. ±0.05 sys. for our best-fitting model. The biases in cosmological parameters in a typical cluster abundance measurement that ignores this mass bias will typically exceed the statistical errors.

Kinematics of our Galaxy from the PMA and TGAS catalogues

NASA Astrophysics Data System (ADS)

Velichko, Anna B.; Akhmetov, Volodymyr S.; Fedorov, Peter N.

2018-04-01

We derive and compare kinematic parameters of the Galaxy using the PMA and Gaia TGAS data. Two methods are used in calculations: evaluation of the Ogorodnikov-Milne model (OMM) parameters by the least square method (LSM) and a decomposition on a set of vector spherical harmonics (VSH). We trace dependencies on the distance of the derived parameters including the Oort constants A and B and the rotational velocity of the Galaxy V rot at the Solar distance for the common sample of stars of mixed spectral composition of the PMA and TGAS catalogues. The distances were obtained from the TGAS parallaxes or from reduced proper motions for fainter stars. The A, B and V rot parameters derived from proper motions of both catalogues used show identical behaviour but the values are systematically shifted by about 0.5 mas/yr. The Oort B parameter derived from the PMA sample of red giants shows gradual decrease with increasing the distance while the Oort A has a minimum at about 2 kpc and then gradually increases. As for models chosen for calculations, first, we confirm conclusions of other authors about the existence of extra-model harmonics in the stellar velocity field. Secondly, not all parameters of the OMM are statistically significant, and the set of parameters depends on the stellar sample used.

VizieR Online Data Catalog: Catalogue of HI maps of galaxies. I. (Martin 1998)

NASA Astrophysics Data System (ADS)

Martin, M. C.

1998-03-01

A catalogue is presented of galaxies having large-scale observations in the HI line. This catalogue collects from the literature the information that characterizes the observations in the 21-cm line and the way that these data were presented by means of maps, graphics and tables, for showing the distribution and kinematics of the gas. It contains furthermore a measure of the HI extension that is detected at the level of the maximum sensitivity reached in the observations. This catalogue is intended as a guide for references on the HI maps published in the literature from 1953 to 1995 and is the basis for the analysis of the data presented in Paper II (Cat. ). (4 data files).

The dependence of galaxy clustering on tidal environment in the Sloan Digital Sky Survey

NASA Astrophysics Data System (ADS)

Paranjape, Aseem; Hahn, Oliver; Sheth, Ravi K.

2018-06-01

The influence of the Cosmic Web on galaxy formation and evolution is of great observational and theoretical interest. We investigate whether the Cosmic Web leaves an imprint in the spatial clustering of galaxies in the Sloan Digital Sky Survey (SDSS), using the group catalogue of Yang et al. and tidal field estimates at ˜2 h-1 Mpc scales from the mass-tides-velocity data set of Wang et al. We use the tidal anisotropy α (Paranjape et al.) to characterize the tidal environment of groups, and measure the redshift-space 2-point correlation function (2pcf) of group positions and the luminosity- and colour-dependent clustering of group galaxies using samples segregated by α. We find that all the 2pcf measurements depend strongly on α, with factors of ˜20 between the large-scale 2pcf of objects in the most and least isotropic environments. To test whether these strong trends imply `beyond halo mass' effects for galaxy evolution, we compare our results with corresponding 2pcf measurements in mock catalogues constructed using a halo occupation distribution that uses only halo mass as an input. We find that this prescription qualitatively reproduces all observed trends, and also quantitatively matches many of the observed results. Although there are some statistically significant differences between our `halo mass only' mocks and the data - in the most and least isotropic environments - which deserve further investigation, our results suggest that if the tidal environment induces additional effects on galaxy properties other than those inherited from their host haloes, then these must be weak.

Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

DOE PAGES

Bonnett, C.; Troxel, M. A.; Hartley, W.; ...

2016-08-30

Here we present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods—annz2, bpz calibrated against BCC-Ufig simulations, skynet, and tpz—are analyzed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-z’s. From the galaxies in the DES SV shear catalogue, which have meanmore » redshift 0.72±0.01 over the range 0.38 of approximately 3%. This shift is within the one sigma statistical errors on σ8 for the DES SV shear catalogue. We further study the potential impact of systematic differences on the critical surface density, Σ crit, finding levels of bias safely less than the statistical power of DES SV data. In conclusion, we recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0.05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.« less

Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonnett, C.; Troxel, M. A.; Hartley, W.

Here we present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods—annz2, bpz calibrated against BCC-Ufig simulations, skynet, and tpz—are analyzed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-z’s. From the galaxies in the DES SV shear catalogue, which have meanmore » redshift 0.72±0.01 over the range 0.38 of approximately 3%. This shift is within the one sigma statistical errors on σ8 for the DES SV shear catalogue. We further study the potential impact of systematic differences on the critical surface density, Σ crit, finding levels of bias safely less than the statistical power of DES SV data. In conclusion, we recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0.05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.« less

A catalogue of faint local radio AGN and the properties of their host galaxies

NASA Astrophysics Data System (ADS)

Lofthouse, E. K.; Kaviraj, S.; Smith, D. JB; Hardcastle, M. J.

2018-05-01

We present a catalogue of local (z < 0.1) galaxies that contain faint AGN. We select these objects by identifying galaxies that exhibit a significant excess in their radio luminosities, compared to what is expected from the observed levels of star-formation activity in these systems. This is achieved by comparing the optical (spectroscopic) star formation rate (SFR) to the 1.4 GHz luminosity measured from the FIRST survey. The majority of the AGN identified in this study are fainter than those in previous work, such as in the Best and Heckman (2012) catalogue. We show that these faint AGN make a non-negligible contribution to the radio luminosity function at low luminosities (below 1022.5 W Hz-1), and host ˜13 per cent of the local radio luminosity budget. Their host galaxies are predominantly high stellar-mass systems (with a median stellar mass of 1011M⊙), are found across a range of environments (but typically in denser environments than star-forming galaxies) and have early-type morphologies. This study demonstrates a general technique to identify AGN in galaxy populations where reliable optical SFRs can be extracted using spectro-photometry and where radio data are also available so that a radio excess can be measured. Our results also demonstrate that it is unsafe to infer SFRs from radio emission alone, even if bright AGN have been excluded from a sample, since there is a significant population of faint radio AGN which may contaminate the radio-derived SFRs.

liger: mock relativistic light cones from Newtonian simulations

NASA Astrophysics Data System (ADS)

Borzyszkowski, Mikolaj; Bertacca, Daniele; Porciani, Cristiano

2017-11-01

We introduce a method to create mock galaxy catalogues in redshift space including general relativistic effects to linear order in the cosmological perturbations. We dub our method liger, short for `light cones with general relativity'. liger takes a (N-body or hydrodynamic) Newtonian simulation as an input and outputs the distribution of galaxies in comoving redshift space. This result is achieved making use of a coordinate transformation and simultaneously accounting for lensing magnification. The calculation includes both local corrections and terms that have been integrated along the line of sight. Our fast implementation allows the production of many realizations that can be used to forecast the performance of forthcoming wide-angle surveys and to estimate the covariance matrix of the observables. To facilitate this use, we also present a variant of liger designed for large-volume simulations with low-mass resolution. In this case, the galaxy distribution on large scales is obtained by biasing the matter-density field. Finally, we present two sample applications of liger. First, we discuss the impact of weak gravitational lensing on to the angular clustering of galaxies in a Euclid-like survey. In agreement with previous analytical studies, we find that magnification bias can be measured with high confidence. Secondly, we focus on two generally neglected Doppler-induced effects: magnification and the change of number counts with redshift. We show that the corresponding redshift-space distortions can be detected at 5.5σ significance with the completed Square Kilometre Array.

Catalogue of HI PArameters (CHIPA)

NASA Astrophysics Data System (ADS)

Saponara, J.; Benaglia, P.; Koribalski, B.; Andruchow, I.

2015-08-01

The catalogue of HI parameters of galaxies HI (CHIPA) is the natural continuation of the compilation by M.C. Martin in 1998. CHIPA provides the most important parameters of nearby galaxies derived from observations of the neutral Hydrogen line. The catalogue contains information of 1400 galaxies across the sky and different morphological types. Parameters like the optical diameter of the galaxy, the blue magnitude, the distance, morphological type, HI extension are listed among others. Maps of the HI distribution, velocity and velocity dispersion can also be display for some cases. The main objective of this catalogue is to facilitate the bibliographic queries, through searching in a database accessible from the internet that will be available in 2015 (the website is under construction). The database was built using the open source `` mysql (SQL, Structured Query Language, management system relational database) '', while the website was built with ''HTML (Hypertext Markup Language)'' and ''PHP (Hypertext Preprocessor)''.

Documentation for the machine-readable version of the Morphological Catalogue of Galaxies (MCG) of Vorontsov-Velyaminov et al, 1962-1968

NASA Technical Reports Server (NTRS)

Warren, W. H., Jr.

1982-01-01

Modifications, corrections, and the record format are provided for the machine-readable version of the "Morphological Catalogue of Galaxies.' In addition to hundreds of individual corrections, a detailed comparison of the machine-readable with the published catalogue resulted in the addition of 116 missing objects, the deletion of 10 duplicate records, and a format modification to increase storage efficiency.

ISOPHOT 170 µm Serendipity Sky Survey: The First Galaxy Catalogue

NASA Astrophysics Data System (ADS)

Stickel, Manfred; Lemke, Dietrich; Klaas, Ulrich; Hotzel, Stephan; Toth, L. Viktor; Kessler, Martin F.; Laureijs, Rene; Burgdorf, Martin; Beichman, Chas A.; Rowan-Robinson, Michael; Efstathiou, Andeas; Bogun, Stefan; Richter, Gotthard; Braun, Michael

The ISOPHOT Serendipity Survey utilized the slew time between ISO's pointed observations with strip scanning measurements of the sky in the far-infrared at 170 µm. From the slew data with low I100µm < 15 MJy/sr) cirrus background, 115 well-observed sources with a high signal-to-noise ratio in all four detector pixels having a galaxy association were extracted. The integral 170 µm fluxes measured from the Serendipity slews have been put on an absolute flux level by using a number of calibrator sources observed with ISOPHOT's photometric mapping mode. For all but a few galaxies, the 170 µm fluxes are determined for the first time, which represents a significant increase in the number of galaxies with measured FIR fluxes beyond the IRAS 100 µm limit. The vast majority of the galaxies are morphologically classified as spirals. The large fraction of sources with a high F170µm / F100µm flux ratio indicates that a very cold (T < 20 K) dust component is present in many galaxies. The typical mass of the coldest dust component is MDust = 107.5 +/- 0.5 M, a factor 2 - 10 larger than that derived from IRAS fluxes alone. As a consequence, the gas-to-dust ratios are much closer to the canonical value of ~~ 160 for the Milky Way. By relaxing the selection criteria, it is expected that the Serendipity survey will eventually lead to a catalogue of 170 µm fluxes for ~~ 1000 galaxies. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA. Members of the Consortium on the ISOPHOT Serendipity Survey (CISS) are MPIA Heidelberg, ESA ISO SOC Villafranca, AIP Potsdam, IPAC Pasadena, Imperial College London.

Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

NASA Astrophysics Data System (ADS)

Clampitt, J.; Sánchez, C.; Kwan, J.; Krause, E.; MacCrann, N.; Park, Y.; Troxel, M. A.; Jain, B.; Rozo, E.; Rykoff, E. S.; Wechsler, R. H.; Blazek, J.; Bonnett, C.; Crocce, M.; Fang, Y.; Gaztanaga, E.; Gruen, D.; Jarvis, M.; Miquel, R.; Prat, J.; Ross, A. J.; Sheldon, E.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Armstrong, R.; Becker, M. R.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

2017-03-01

We present galaxy-galaxy lensing results from 139 deg2 of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise ratio of 29 over scales 0.09 < R < 15 Mpc h-1, including all lenses over a wide redshift range 0.2 < z < 0.8. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtain consistent results for the lensing measurement with two independent shear pipelines, NGMIX and IM3SHAPE. We perform a number of null tests on the shear and photometric redshift catalogues and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The result and systematic checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a halo occupation distribution (HOD) model, and demonstrate that our data constrain the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.

Initiating the Sierra Nevada catalogue of star-forming polar-ring galaxies

NASA Astrophysics Data System (ADS)

Garcia-Ribera, E.; Pérez-Montero, E.; García-Benito, R.; Vílchez, J. M.

2015-05-01

We describe photometric observations with the 1.5m. telescope of the Sierra Nevada Observatory of a preliminary sample of 16 candidates to polar-ring galaxies (PRGs) selected from Whitmore et al. (1990) and Moiseev et al. (2011). The images were taken in broad filters (BVR) in order to characterize the host galaxies and the rings and in narrow filter Hα at the corresponding redshifted wavelength to identify in the rings knots of on-going star-formation. These information allowed us to analyze different physical parameters (formation scenarios, morphological types, and stellar population) and to locate HII regions. The main aim of this work is the elaboration of a catalogue of PRGs with a star-forming ring. In a next future, the spatially-resolved spectroscopy study of these structures will help to understand their most probable mechanism of origin, formation and evolution by means of rotation curves, spectral fitting of stellar populations and chemical abundance analysis (e.g. Pérez-Montero et al. 2009)

Catalogue of the morphological features in the Spitzer Survey of Stellar Structure in Galaxies (S4G)

NASA Astrophysics Data System (ADS)

Herrera-Endoqui, M.; Díaz-García, S.; Laurikainen, E.; Salo, H.

2015-10-01

Context. A catalogue of the features for the complete Spitzer Survey of Stellar Structure in Galaxies (S4G), including 2352 nearby galaxies, is presented. The measurements are made using 3.6 μm images, largely tracing the old stellar population; at this wavelength the effects of dust are also minimal. The measured features are the sizes, ellipticities, and orientations of bars, rings, ringlenses, and lenses. Measured in a similar manner are also barlenses (lens-like structures embedded in the bars), which are not lenses in the usual sense, being rather the more face-on counterparts of the boxy/peanut structures in the edge-on view. In addition, pitch angles of spiral arm segments are measured for those galaxies where they can be reliably traced. More than one pitch angle may appear for a single galaxy. All measurements are made in a human-supervised manner so that attention is paid to each galaxy. Aims: We create a catalogue of morphological features in the complete S4G. Methods: We used isophotal analysis, unsharp masking, and fitting ellipses to measured structures. Results: We find that the sizes of the inner rings and lenses normalized to barlength correlate with the galaxy mass: the normalized sizes increase toward the less massive galaxies; it has been suggested that this is related to the larger dark matter content in the bar region in these systems. Bars in the low mass galaxies are also less concentrated, likely to be connected to the mass cut-off in the appearance of the nuclear rings and lenses. We also show observational evidence that barlenses indeed form part of the bar, and that a large fraction of the inner lenses in the non-barred galaxies could be former barlenses in which the thin outer bar component has dissolved. Full Tables 2 and 3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/582/A86

The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS): survey design, data catalogue and GAMA/WiggleZ spectroscopy

NASA Astrophysics Data System (ADS)

Ching, John H. Y.; Sadler, Elaine M.; Croom, Scott M.; Johnston, Helen M.; Pracy, Michael B.; Couch, Warrick J.; Hopkins, A. M.; Jurek, Russell J.; Pimbblet, K. A.

2017-01-01

We present the Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS), a spectroscopic catalogue of radio sources designed to include the full range of radio AGN populations out to redshift z ˜ 0.8. The catalogue covers ˜800 deg2 of sky, and provides optical identifications for 19 179 radio sources from the 1.4 GHz Faint Images of the Radio Sky at Twenty-cm (FIRST) survey down to an optical magnitude limit of Imod < 20.5 in Sloan Digital Sky Survey (SDSS) images. Both galaxies and point-like objects are included, and no colour cuts are applied. In collaboration with the WiggleZ and Galaxy And Mass Assembly (GAMA) spectroscopic survey teams, we have obtained new spectra for over 5000 objects in the LARGESS sample. Combining these new spectra with data from earlier surveys provides spectroscopic data for 12 329 radio sources in the survey area, of which 10 856 have reliable redshifts. 85 per cent of the LARGESS spectroscopic sample are radio AGN (median redshift z = 0.44), and 15 per cent are nearby star-forming galaxies (median z = 0.08). Low-excitation radio galaxies (LERGs) comprise the majority (83 per cent) of LARGESS radio AGN at z < 0.8, with 12 per cent being high-excitation radio galaxies (HERGs) and 5 per cent radio-loud QSOs. Unlike the more homogeneous LERG and QSO sub-populations, HERGs are a heterogeneous class of objects with relatively blue optical colours and a wide dispersion in mid-infrared colours. This is consistent with a picture in which most HERGs are hosted by galaxies with recent or ongoing star formation as well as a classical accretion disc.

COSMOS2015 photometric redshifts probe the impact of filaments on galaxy properties

NASA Astrophysics Data System (ADS)

Laigle, C.; Pichon, C.; Arnouts, S.; McCracken, H. J.; Dubois, Y.; Devriendt, J.; Slyz, A.; Le Borgne, D.; Benoit-Lévy, A.; Hwang, Ho Seong; Ilbert, O.; Kraljic, K.; Malavasi, N.; Park, Changbom; Vibert, D.

2018-03-01

The variation of galaxy stellar masses and colour types with the distance to projected cosmic filaments are quantified using the precise photometric redshifts of the COSMOS2015 catalogue extracted from Cosmological Evolution Survey (COSMOS) field (2 deg2). Realistic mock catalogues are also extracted from the lightcone of the cosmological hydrodynamical simulation HORIZON-AGN. They show that the photometric redshift accuracy of the observed catalogue (σz < 0.015 at M* > 1010M⊙ and z < 0.9) is sufficient to provide two-dimensional (2D) filaments that closely match their projected three-dimensional (3D) counterparts. Transverse stellar mass gradients are measured in projected slices of thickness 75 Mpc between 0.5 < z < 0.9, showing that the most massive galaxies are statistically closer to their neighbouring filament. At fixed stellar mass, passive galaxies are also found closer to their filament, while active star-forming galaxies statistically lie further away. The contributions of nodes and local density are removed from these gradients to highlight the specific role played by the geometry of the filaments. We find that the measured signal does persist after this removal, clearly demonstrating that proximity to a filament is not equivalent to proximity to an overdensity. These findings are in agreement with gradients measured in both 2D and 3D in the HORIZON-AGN simulation and those observed in the spectroscopic surveys VIPERS and GAMA (which both rely on the identification of 3D filaments). They are consistent with a picture in which the influence of the geometry of the large-scale environment drives anisotropic tides that impact the assembly history of galaxies, and hence their observed properties.

Galaxy-galaxy weak gravitational lensing in f(R) gravity

NASA Astrophysics Data System (ADS)

Li, Baojiu; Shirasaki, Masato

2018-03-01

We present an analysis of galaxy-galaxy weak gravitational lensing (GGL) in chameleon f(R) gravity - a leading candidate of non-standard gravity models. For the analysis, we have created mock galaxy catalogues based on dark matter haloes from two sets of numerical simulations, using a halo occupation distribution (HOD) prescription which allows a redshift dependence of galaxy number density. To make a fairer comparison between the f(R) and Λ cold dark matter (ΛCDM) models, their HOD parameters are tuned so that the galaxy two-point correlation functions in real space (and therefore the projected two-point correlation functions) match. While the f(R) model predicts an enhancement of the convergence power spectrum by up to ˜ 30 per cent compared to the standard ΛCDM model with the same parameters, the maximum enhancement of GGL is only half as large and less than 5 per cent on separations above ˜1-2 h-1 Mpc, because the latter is a cross-correlation of shear (or matter, which is more strongly affected by modified gravity) and galaxy (which is weakly affected given the good match between galaxy autocorrelations in the two models) fields. We also study the possibility of reconstructing the matter power spectrum by combination of GGL and galaxy clustering in f(R) gravity. We find that the galaxy-matter cross-correlation coefficient remains at unity down to ˜2-3 h-1 Mpc at relevant redshifts even in f(R) gravity, indicating joint analysis of GGL and galaxy clustering can be a powerful probe of matter density fluctuations in chameleon gravity. The scale dependence of the model differences in their predictions of GGL can potentially allows us to break the degeneracy between f(R) gravity and other cosmological parameters such as Ωm and σ8.

Galaxy–galaxy lensing estimators and their covariance properties

DOE PAGES

Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uros; ...

2017-07-21

Here, we study the covariance properties of real space correlation function estimators – primarily galaxy–shear correlations, or galaxy–galaxy lensing – using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens densitymore » field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.« less

Galaxy–galaxy lensing estimators and their covariance properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uros

Here, we study the covariance properties of real space correlation function estimators – primarily galaxy–shear correlations, or galaxy–galaxy lensing – using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens densitymore » field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.« less

The dark matter of galaxy voids

NASA Astrophysics Data System (ADS)

Sutter, P. M.; Lavaux, Guilhem; Wandelt, Benjamin D.; Weinberg, David H.; Warren, Michael S.

2014-03-01

How do observed voids relate to the underlying dark matter distribution? To examine the spatial distribution of dark matter contained within voids identified in galaxy surveys, we apply Halo Occupation Distribution models representing sparsely and densely sampled galaxy surveys to a high-resolution N-body simulation. We compare these galaxy voids to voids found in the halo distribution, low-resolution dark matter and high-resolution dark matter. We find that voids at all scales in densely sampled surveys - and medium- to large-scale voids in sparse surveys - trace the same underdensities as dark matter, but they are larger in radius by ˜20 per cent, they have somewhat shallower density profiles and they have centres offset by ˜ 0.4Rv rms. However, in void-to-void comparison we find that shape estimators are less robust to sampling, and the largest voids in sparsely sampled surveys suffer fragmentation at their edges. We find that voids in galaxy surveys always correspond to underdensities in the dark matter, though the centres may be offset. When this offset is taken into account, we recover almost identical radial density profiles between galaxies and dark matter. All mock catalogues used in this work are available at http://www.cosmicvoids.net.

Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Espada, D.; Leon, S.; Sánchez-Expósito, S.; Santander-Vela, J. D.; Verdes-Montenegro, L.

2014-04-01

Context. We present a study of the 3D environment for a sample of 386 galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973) using the Ninth Data Release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the CIG, as well as the effects of the large-scale structure (LSS). Methods: To recover the physically bound galaxies we first focused on the satellites that are within the escape speed of each CIG galaxy. We also propose a more conservative method using the stacked Gaussian distribution of the velocity difference of the neighbours. The tidal strengths affecting the primary galaxy were estimated to quantify the effects of the local and LSS environments. We also defined the projected number density parameter at the fifth nearest neighbour to characterise the LSS around the CIG galaxies. Results: Out of the 386 CIG galaxies considered in this study, at least 340 (88% of the sample) have no physically linked satellite. Following the more conservative Gaussian distribution of physical satellites around the CIG galaxies leads to upper limits. Out of the 386 CIG galaxies, 327 (85% of the sample) have no physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are distributed following the LSS of the local Universe, although presenting a large heterogeneity in their degree of connection with it. When present around a CIG galaxy, the effect of physically bound galaxies largely dominates (typically by more than 90%) the tidal strengths generated by the LSS. Conclusions: The CIG samples a variety of environments, from galaxies with physical satellites to galaxies without neighbours within 3 Mpc. A clear segregation appears between early-type CIG galaxies with companions and isolated late-type CIG galaxies. Isolated galaxies are in general bluer, with probably younger stellar populations and very high star formation compared with older

VizieR Online Data Catalog: SDSS-based Polar Ring Catalogue (Moiseev+, 2011)

NASA Astrophysics Data System (ADS)

Moiseev, A. V.; Smirnova, K. I.; Smirnova, A. A.; Reshetnikov, V. P.

2012-06-01

Galaxies with polar rings (PRGs) are a unique class of extragalactic objects. Using these, we can investigate a wide range of problems, linked to the formation and evolution of galaxies, and we can study the properties of their dark haloes. The progress that has been made in the study of PRGs has been constrained by the small number of known objects of this type. The Polar Ring Catalogue (PRC) by Whitmore et al. (1990AJ....100.1489W) and their photographic atlas of PRGs and related objects includes 157 galaxies. At present, there are only about two dozen kinematically confirmed galaxies in this PRG class, mostly from the PRC. We present a new catalogue of PRGs, supplementing the PRC and significantly increasing the number of known candidate PRGs. The catalogue is based on the results of the original Galaxy Zoo project. Within this project, volunteers performed visual classifications of nearly a million galaxies from the Sloan Digital Sky Survey (SDSS). Based on the preliminary classifications of the Galaxy Zoo, we viewed more than 40000 images of the SDSS and selected 275 galaxies to include in our catalogue. (1 data file).

A comprehensive HST BVI catalogue of star clusters in five Hickson compact groups of galaxies

NASA Astrophysics Data System (ADS)

Fedotov, K.; Gallagher, S. C.; Durrell, P. R.; Bastian, N.; Konstantopoulos, I. S.; Charlton, J.; Johnson, K. E.; Chandar, R.

2015-05-01

We present a photometric catalogue of star cluster candidates in Hickson compact groups (HCGs) 7, 31, 42, 59, and 92, based on observations with the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope. The catalogue contains precise cluster positions (right ascension and declination), magnitudes, and colours in the BVI filters. The number of detected sources ranges from 2200 to 5600 per group, from which we construct the high-confidence sample by applying a number of criteria designed to reduce foreground and background contaminants. Furthermore, the high-confidence cluster candidates for each of the 16 galaxies in our sample are split into two subpopulations: one that may contain young star clusters and one that is dominated by globular older clusters. The ratio of young star cluster to globular cluster candidates varies from group to group, from equal numbers to the extreme of HCG 31 which has a ratio of 8 to 1, due to a recent starburst induced by interactions in the group. We find that the number of blue clusters with MV < -9 correlates well with the current star formation rate in an individual galaxy, while the number of globular cluster candidates with MV < -7.8 correlates well (though with large scatter) with the stellar mass. Analyses of the high-confidence sample presented in this paper show that star clusters can be successfully used to infer the gross star formation history of the host groups and therefore determine their placement in a proposed evolutionary sequence for compact galaxy groups.

The JWST Extragalactic Mock Catalog: Modeling Galaxy Populations from the UV through the Near-IR over 13 Billion Years of Cosmic History

NASA Astrophysics Data System (ADS)

Williams, Christina C.; Curtis-Lake, Emma; Hainline, Kevin N.; Chevallard, Jacopo; Robertson, Brant E.; Charlot, Stephane; Endsley, Ryan; Stark, Daniel P.; Willmer, Christopher N. A.; Alberts, Stacey; Amorin, Ricardo; Arribas, Santiago; Baum, Stefi; Bunker, Andrew; Carniani, Stefano; Crandall, Sara; Egami, Eiichi; Eisenstein, Daniel J.; Ferruit, Pierre; Husemann, Bernd; Maseda, Michael V.; Maiolino, Roberto; Rawle, Timothy D.; Rieke, Marcia; Smit, Renske; Tacchella, Sandro; Willott, Chris J.

2018-06-01

We present an original phenomenological model to describe the evolution of galaxy number counts, morphologies, and spectral energy distributions across a wide range of redshifts (0.2< z< 15) and stellar masses [{log}(M/{M}ȯ )≥slant 6]. Our model follows observed mass and luminosity functions of both star-forming and quiescent galaxies, and reproduces the redshift evolution of colors, sizes, star formation, and chemical properties of the observed galaxy population. Unlike other existing approaches, our model includes a self-consistent treatment of stellar and photoionized gas emission and dust attenuation based on the BEAGLE tool. The mock galaxy catalogs generated with our new model can be used to simulate and optimize extragalactic surveys with future facilities such as the James Webb Space Telescope (JWST), and to enable critical assessments of analysis procedures, interpretation tools, and measurement systematics for both photometric and spectroscopic data. As a first application of this work, we make predictions for the upcoming JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations teams. We show that JADES will detect, with NIRCam imaging, 1000s of galaxies at z ≳ 6, and 10s at z ≳ 10 at {m}{AB}≲ 30 (5σ) within the 236 arcmin2 of the survey. The JADES data will enable accurate constraints on the evolution of the UV luminosity function at z > 8, and resolve the current debate about the rate of evolution of galaxies at z ≳ 8. Ready-to-use mock catalogs and software to generate new realizations are publicly available as the JAdes extraGalactic Ultradeep Artificial Realizations (JAGUAR) package.

Unbiased estimates of galaxy scaling relations from photometric redshift surveys

NASA Astrophysics Data System (ADS)

Rossi, Graziano; Sheth, Ravi K.

2008-06-01

Many physical properties of galaxies correlate with one another, and these correlations are often used to constrain galaxy formation models. Such correlations include the colour-magnitude relation, the luminosity-size relation, the fundamental plane, etc. However, the transformation from observable (e.g. angular size, apparent brightness) to physical quantity (physical size, luminosity) is often distance dependent. Noise in the distance estimate will lead to biased estimates of these correlations, thus compromising the ability of photometric redshift surveys to constrain galaxy formation models. We describe two methods which can remove this bias. One is a generalization of the Vmax method, and the other is a maximum-likelihood approach. We illustrate their effectiveness by studying the size-luminosity relation in a mock catalogue, although both methods can be applied to other scaling relations as well. We show that if one simply uses photometric redshifts one obtains a biased relation; our methods correct for this bias and recover the true relation.

Cosmological Parameter Estimation Using the Genus Amplitude—Application to Mock Galaxy Catalogs

NASA Astrophysics Data System (ADS)

Appleby, Stephen; Park, Changbom; Hong, Sungwook E.; Kim, Juhan

2018-01-01

We study the topology of the matter density field in two-dimensional slices and consider how we can use the amplitude A of the genus for cosmological parameter estimation. Using the latest Horizon Run 4 simulation data, we calculate the genus of the smoothed density field constructed from light cone mock galaxy catalogs. Information can be extracted from the amplitude of the genus by considering both its redshift evolution and magnitude. The constancy of the genus amplitude with redshift can be used as a standard population, from which we derive constraints on the equation of state of dark energy {w}{de}—by measuring A at z∼ 0.1 and z∼ 1, we can place an order {{Δ }}{w}{de}∼ { O }(15 % ) constraint on {w}{de}. By comparing A to its Gaussian expectation value, we can potentially derive an additional stringent constraint on the matter density {{Δ }}{{{Ω }}}{mat}∼ 0.01. We discuss the primary sources of contamination associated with the two measurements—redshift space distortion (RSD) and shot noise. With accurate knowledge of galaxy bias, we can successfully remove the effect of RSD, and the combined effect of shot noise and nonlinear gravitational evolution is suppressed by smoothing over suitably large scales {R}{{G}}≥slant 15 {Mpc}/h. Without knowledge of the bias, we discuss how joint measurements of the two- and three-dimensional genus can be used to constrain the growth factor β =f/b. The method can be applied optimally to redshift slices of a galaxy distribution generated using the drop-off technique.

THE DEEP2 GALAXY REDSHIFT SURVEY: THE VORONOI-DELAUNAY METHOD CATALOG OF GALAXY GROUPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc

2012-05-20

We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 < z < 1.5 and 1295 groups at z > 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it hasmore » been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above {approx}300 km s{sup -1} to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for

A catalogue of AKARI FIS BSC extragalactic objects

NASA Astrophysics Data System (ADS)

Marton, Gabor; Toth, L. Viktor; Gyorgy Balazs, Lajos

2015-08-01

We combined photometric data of about 70 thousand point sources from the AKARI Far-Infrared Surveyor Bright Source Catalogue with AllWISE catalogue data to identify galaxies. We used Quadratic Discriminant Analysis (QDA) to classify our sources. The classification was based on a 6D parameter space that contained AKARI [F65/F90], [F90/F140], [F140/F160] and WISE W1-W2 colours along with WISE W1 magnitudes and AKARI [F140] flux values. Sources were classified into 3 main objects types: YSO candidates, evolved stars and galaxies. The training samples were SIMBAD entries of the input point sources wherever an associated SIMBAD object was found within a 30 arcsecond search radius. The QDA resulted more than 5000 AKARI galaxy candidate sources. The selection was tested cross-correlating our AKARI extragalactic catalogue with the Revised IRAS-FSC Redshift Catalogue (RIFSCz). A very good match was found. A further classification attempt was also made to differentiate between extragalactic subtypes using Support Vector Machines (SVMs). The results of the various methods showed that we can confidently separate cirrus dominated objects (type 1 of RIFSCz). Some of our “galaxy candidate” sources are associated with 2MASS extended objects, and listed in the NASA Extragalactic Database so far without clear proofs of their extragalactic nature. Examples will be presented in our poster. Finally other AKARI extragalactic catalogues will be also compared to our statistical selection.

Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonnett, C.; Troxel, M. A.; Hartley, W.

We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods { annz2, bpz calibrated against BCC-U fig simulations, skynet, and tpz { are analysed. For training, calibration, and testing of these methods, we also construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evalu-ated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-zs. From the galaxies in the DES SVmore » shear catalogue, which have mean redshift 0.72 ±0.01 over the range 0:3 < z < 1:3, we construct three tomographic bins with means of z = {0.45; 0.67,1.00g}. These bins each have systematic uncertainties δ z ≲ 0.05 in the mean of the fiducial skynet photo-z n(z). We propagate the errors in the redshift distributions through to their impact on cosmological parameters estimated with cosmic shear, and find that they cause shifts in the value of σ 8 of approx. 3%. This shift is within the one sigma statistical errors on σ8 for the DES SV shear catalog. We also found that further study of the potential impact of systematic differences on the critical surface density, Σ crit, contained levels of bias safely less than the statistical power of DES SV data. We recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0:05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.« less

Unbiased constraints on ultralight axion mass from dwarf spheroidal galaxies

NASA Astrophysics Data System (ADS)

González-Morales, Alma X.; Marsh, David J. E.; Peñarrubia, Jorge; Ureña-López, Luis A.

2017-12-01

It has been suggested that the internal dynamics of dwarf spheroidal galaxies (dSphs) can be used to test whether or not ultralight axions with ma ∼ 10-22 eV are a preferred dark matter candidate. However, comparisons to theoretical predictions tend to be inconclusive for the simple reason that while most cosmological models consider only dark matter, one observes only baryons. Here, we use realistic kinematic mock data catalogues of Milky Way (MW) dSph's to show that the 'mass-anisotropy degeneracy' in the Jeans equations leads to biased bounds on the axion mass in galaxies with unknown dark matter halo profiles. In galaxies with multiple chemodynamical components, this bias can be partly removed by modelling the mass enclosed within each subpopulation. However, analysis of the mock data reveals that the least-biased constraints on the axion mass result from fitting the luminosity-averaged velocity dispersion of the individual chemodynamical components directly. Applying our analysis to two dSph's with reported stellar subcomponents, Fornax and Sculptor, and assuming that the halo profile has not been acted on by baryons, yields core radii rc > 1.5 and 1.2 kpc, respectively, and ma < 0.4 × 10-22 eV at 97.5 per cent confidence. These bounds are in tension with the number of observed satellites derived from simple (but conservative) estimates of the subhalo mass function in MW-like galaxies. We discuss how baryonic feedback might affect our results, and the impact of such a small axion mass on the growth of structures in the Universe.

Total magnitudes of Virgo galaxies - III. Scale errors in the Reference Catalogue of Bright Galaxies T system and light-profile distortion by resolution-degrading and differential-distance effects

NASA Astrophysics Data System (ADS)

Young, Christopher Ke-shih

2004-11-01

We investigate the BT magnitude scales of the Second and Third Reference Catalogues of Bright Galaxies, finding both scales to be reasonably reliable for 11.5 <~Bt<~ 14.0. However, large-scale errors of 0.26 and 0.24mag per unit mag interval respectively are uncovered for early-type galaxies at the bright ends, whilst even larger ones of 0.74 and 0.36mag per unit mag interval are found for galaxies of all morphological types at the faint ends. We attribute this situation to several effects already discussed by Young et al. and Young (Paper I), including the application of relatively inflexible growth-curve models that are only in a few specific cases appropriate to the galaxies concerned. Of particular interest to this study though, we find that the apparent profile shapes of giant galaxies in the Virgo direction of cz < 15000 km s-1 tend to be less centrally concentrated the greater their distance. This demonstrates that even for relatively nearby galaxies, the distortion of the overall shapes of light profiles by resolution-degrading effects such as seeing and data smoothing, as originally predicted and modelled by Young & Currie and Young et al., is a significant effect. It is, therefore, not good practice simply to extrapolate the profiles of galaxies of identical intrinsic size and intrinsic profile shape (i.e. identical morphology) by means of the same growth-curve model, unless the galaxies are known a priori to be at the same distance and unless their photometry is of the same angular resolution. We also investigate the total-magnitude scale of the catalogue of photometric types of Prugniel & Héraudeau, finding it to be much more reliable than the BT one. However, we argue that photometric type is really a measure of apparent profile shape (i.e. intrinsic profile shape after scale reduction on account of distance followed by convolution with a seeing disc and often a smoothing function as well). Strictly, it should therefore only be applicable to

Creation of a Mock Universe: Photometric Astronomy on Simulation

NASA Astrophysics Data System (ADS)

Nene, Ajinkya; Rodriguez, Aldo; Primack, Joel R.

2016-01-01

A major focus in astronomy is to understand how galaxies form and evolve in the Universe. The current model known as ΛCDM explains that galaxies form and evolve in halos composed of cold dark matter. In an effort to understand galactic processes in relation to halos, researchers have developed statistical methods to connect galaxies to their halos. One of these approaches is abundance matching: a technique in which the galaxy number density of a property is connected to a theoretical halo number density. In this study, we exploit the abundance matching technique and create a massive photometric mock catalog. We populate millions of dark matter halos in the Bolshoi-Planck Simulation with highly defined galaxies that each has: luminosities, magnitudes, fluxes, masses, and Sérsic profiles. Our catalog acts as an interface between cold dark matter theory and observations: astronomers can use this mock galaxy catalog to compare ΛCDM predictions to observations as well as constrain galaxy formation models. Using our catalog, we can make powerful predictions about both theoretical data and about future astronomical surveys. We demonstrate the usability of our catalog through angular power spectra. Specifically, we shed light on the controversial intrahalo light phenomena. We emphasize that this is the first catalog of this accuracy and size and has incredible potential for application.

IMCAT: Image and Catalogue Manipulation Software

NASA Astrophysics Data System (ADS)

Kaiser, Nick

2011-08-01

The IMCAT software was developed initially to do faint galaxy photometry for weak lensing studies, and provides a fairly complete set of tools for this kind of work. Unlike most packages for doing data analysis, the tools are standalone unix commands which you can invoke from the shell, via shell scripts or from perl scripts. The tools are arranges in a tree of directories. One main branch is the ’imtools’. These deal only with fits files. The most important imtool is the ’image calculator’ ’ic’ which allows one to do rather general operations on fits images. A second branch is the ’catools’ which operate only on catalogues. The key cattool is ’lc’; this effectively defines the format of IMCAT catalogues, and allows one to do very general operations on and filtering of such catalogues. A third branch is the ’imcattools’. These tend to be much more specialised than the cattools and imcattools and are focussed on faint galaxy photometry.

GalMod: the last frontier of Galaxy population synthesis models

NASA Astrophysics Data System (ADS)

Pasetto, Stefano; Kollmeier, Juna; Grebel, Eva K.; chiosi, cesare

2018-01-01

We present a novel Galaxy population synthesis model: GalMod (Pasetto et al. 2016, 2017a,b) is the only star-count model featuring an asymmetric bar/bulge as well as spiral arms as directly obtained by applying linear perturbative theory to self-consistent distribution function of the Galaxy stellar populations. Compared to previous literature models (e.g., Besancon, Trilegal), GalMod allows to generate full-sky mock catalogue, M31 surveys and provides a better match to observed Milky Way (MW) stellar fields.The model can generate synthetic mock catalogs of visible portions of the MW, external galaxies like M31, or N-body simulation initial conditions. At any given time, e.g., a chosen age of the Galaxy, the model contains a sum of discrete stellar populations, namely bulge/bar, disk, halo. The disk population is itself the sum of subpopulations: spiral arms, thin disk, thick disk, and gas component, while the halo is modeled as the sum of a stellar component, a hot coronal gas, and a dark matter component. The Galactic potential is computed from these subpopulations' density profiles and used to generate detailed kinematics by considering the first few moments of the Boltzmann collisionless equation for all the stellar subpopulations. The same density profiles are then used to define the observed color-magnitude diagrams within an input field of view from an arbitrary solar location. Several photometric systems have been included and made available on-line, e.g., SDSS, Gaia, 2MASS, HST WFC3, and others. Finally, we model the extinction with advanced ray tracing solutions.The model's web page (and tutorial) can be accessed at www.GalMod.org.

James Dunlop's historical catalogue of southern nebulae and clusters

NASA Astrophysics Data System (ADS)

Cozens, Glen; Walsh, Andrew; Orchiston, Wayne

2010-03-01

In 1826 James Dunlop compiled the second ever catalogue of southern star clusters, nebulae and galaxies from Parramatta (NSW, Australia) using a 23-cm reflecting telescope. Initially acclaimed, the catalogue and author were later criticised and condemned by others - including Sir John Herschel and both the catalogue and author are now largely unknown. The criticism of the catalogue centred on the large number of fictitious or ‘missing’ objects, yet detailed analysis reveals the remarkable completeness of the catalogue, despite its inherent errors. We believe that James Dunlop was an important early Australian astronomer, and his catalogue should be esteemed as the southern equivalent of Messier's famous northern catalogue.

Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, C.; Pujol, A.; Gaztañaga, E.

We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg 2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars inmore » four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2–0.4), 0.97 ± 0.15 (z = 0.4–0.6), 1.38 ± 0.39 (z = 0.6–0.8), and 1.45 ± 0.56 (z = 0.8–1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Moreover, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.« less

Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

DOE PAGES

Chang, C.; Pujol, A.; Gaztañaga, E.; ...

2016-04-15

We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg 2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars inmore » four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2–0.4), 0.97 ± 0.15 (z = 0.4–0.6), 1.38 ± 0.39 (z = 0.6–0.8), and 1.45 ± 0.56 (z = 0.8–1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Moreover, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.« less

A new catalogue of ultraluminous X-ray sources (and more!)

NASA Astrophysics Data System (ADS)

Roberts, T.; Earnshaw, H.; Walton, D.; Middleton, M.; Mateos, S.

2017-10-01

Many of the critical issues of ultraluminous X-ray source (ULX) science - for example the prevalence of IMBH and/or ULX pulsar candidates within the wider ULX population - can only be addressed by studying statistical samples of ULXs. Similarly, characterising the range of properties displayed by ULXs, and so understanding their accretion physics, requires large samples of objects. To this end, we introduce a new catalogue of 376 ultraluminous X-ray sources and 1092 less luminous point X-ray sources associated with nearby galaxies, derived from the 3XMM-DR4 catalogue. We highlight applications of this catalogue, for example the identification of new IMBH candidates from the most luminous ULXs; and examining the physics of objects at the Eddington threshold, where their luminosities of ˜ 10^{39} erg s^{-1} indicate their accretion rates are ˜ Eddington. We also show how the catalogue can be used to start to examine a wider range of lower luminosity (sub-ULX) point sources in star forming galaxies than previously accessible through spectral stacking, and argue why this is important for galaxy formation in the high redshift Universe.

Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database

NASA Astrophysics Data System (ADS)

Buta, Ronald J.

2017-11-01

Rings are important and characteristic features of disc-shaped galaxies. This paper is the first in a series that re-visits galactic rings with the goals of further understanding the nature of the features and for examining their role in the secular evolution of galaxy structure. The series begins with a new sample of 3962 galaxies drawn from the Galaxy Zoo 2 citizen science data base, selected because zoo volunteers recognized a ring-shaped pattern in the morphology as seen in Sloan Digital Sky Survey colour images. The galaxies are classified within the framework of the Comprehensive de Vaucouleurs revised Hubble-Sandage system. It is found that zoo volunteers cued on the same kinds of ring-like features that were recognized in the 1995 Catalogue of Southern Ringed Galaxies. This paper presents the full catalogue of morphological classifications, comparisons with other sources of classifications and some histograms designed mainly to highlight the content of the catalogue. The advantages of the sample are its large size and the generally good quality of the images; the main disadvantage is the low physical resolution that limits the detectability of linearly small rings such as nuclear rings. The catalogue includes mainly inner and outer disc rings and lenses. Cataclysmic (`encounter-driven') rings (such as ring and polar ring galaxies) are recognized in less than 1 per cent of the sample.

Connecting massive galaxies to dark matter haloes in BOSS - I. Is galaxy colour a stochastic process in high-mass haloes?

NASA Astrophysics Data System (ADS)

Saito, Shun; Leauthaud, Alexie; Hearin, Andrew P.; Bundy, Kevin; Zentner, Andrew R.; Behroozi, Peter S.; Reid, Beth A.; Sinha, Manodeep; Coupon, Jean; Tinker, Jeremy L.; White, Martin; Schneider, Donald P.

2016-08-01

We use subhalo abundance matching (SHAM) to model the stellar mass function (SMF) and clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) `CMASS' sample at z ˜ 0.5. We introduce a novel method which accounts for the stellar mass incompleteness of CMASS as a function of redshift, and produce CMASS mock catalogues which include selection effects, reproduce the overall SMF, the projected two-point correlation function wp, the CMASS dn/dz, and are made publicly available. We study the effects of assembly bias above collapse mass in the context of `age matching' and show that these effects are markedly different compared to the ones explored by Hearin et al. at lower stellar masses. We construct two models, one in which galaxy colour is stochastic (`AbM' model) as well as a model which contains assembly bias effects (`AgM' model). By confronting the redshift dependent clustering of CMASS with the predictions from our model, we argue that that galaxy colours are not a stochastic process in high-mass haloes. Our results suggest that the colours of galaxies in high-mass haloes are determined by other halo properties besides halo peak velocity and that assembly bias effects play an important role in determining the clustering properties of this sample.

Smoothing the redshift distributions of random samples for the baryon acoustic oscillations: applications to the SDSS-III BOSS DR12 and QPM mock samples

NASA Astrophysics Data System (ADS)

Wang, Shao-Jiang; Guo, Qi; Cai, Rong-Gen

2017-12-01

We investigate the impact of different redshift distributions of random samples on the baryon acoustic oscillations (BAO) measurements of D_V(z)r_d^fid/r_d from the two-point correlation functions of galaxies in the Data Release 12 of the Baryon Oscillation Spectroscopic Survey (BOSS). Big surveys, such as BOSS, usually assign redshifts to the random samples by randomly drawing values from the measured redshift distributions of the data, which would necessarily introduce fiducial signals of fluctuations into the random samples, weakening the signals of BAO, if the cosmic variance cannot be ignored. We propose a smooth function of redshift distribution that fits the data well to populate the random galaxy samples. The resulting cosmological parameters match the input parameters of the mock catalogue very well. The significance of BAO signals has been improved by 0.33σ for a low-redshift sample and by 0.03σ for a constant-stellar-mass sample, though the absolute values do not change significantly. Given the precision of the measurements of current cosmological parameters, it would be appreciated for the future improvements on the measurements of galaxy clustering.

Percolation analysis for cosmic web with discrete points

NASA Astrophysics Data System (ADS)

Zhang, Jiajun; Cheng, Dalong; Chu, Ming-Chung

2016-03-01

Percolation analysis has long been used to quantify the connectivity of the cosmic web. Unlike most of the previous works using density field on grids, we have studied percolation analysis based on discrete points. Using a Friends-of-Friends (FoF) algorithm, we generate the S-bb relation, between the fractional mass of the largest connected group (S) and the FoF linking length (bb). We propose a new model, the Probability Cloud Cluster Expansion Theory (PCCET) to relate the S-bb relation with correlation functions. We show that the S-bb relation reflects a combination of all orders of correlation functions. We have studied the S-bb relation with simulation and find that the S-bb relation is robust against redshift distortion and incompleteness in observation. From the Bolshoi simulation, with Halo Abundance Matching (HAM), we have generated a mock galaxy catalogue. Good matching of the projected two-point correlation function with observation is confirmed. However, comparing the mock catalogue with the latest galaxy catalogue from SDSS DR12, we have found significant differences in their S-bb relations. This indicates that the mock catalogue cannot accurately recover higher order correlation functions than the two-point correlation function, which reveals the limit of HAM method.

Analysis of the star formation histories of galaxies in different environments: from low to high density

NASA Astrophysics Data System (ADS)

Ortega-Minakata, René A.

2015-11-01

In this thesis, a value-added cataloge of 403,372 SDSS-DR7 galaxies is presented. This catalogue incorporates information on their stellar populations, including their star formation histories, their dominant emission-line activity type, inferred morphology and a measurement of their environmental density. The sample that formed this catalogue was selected from the SDSS-DR7 (Legacy) spectroscopic catalogue of galaxies in the Northern Galactic Cap, selecting only galaxies with high-quality spectra and redshift determination, and photometric measurements with small errors. Also, galaxies near the edge of the photometric survey footprint were excluded to avoid errors in the determination of their environment. Only galaxies in the 0.03-0.30 redshift range were considered. Starlight fits of the spectra of these galaxies were used to obtain information on their star formation history and stellar mass, velocity dispersion and mean age. From the fit residuals, emission-line fluxes were measured and used to obtain the dominant activity type of these galaxies using the BPT diagnostic diagram. A neighbour search code was written and applied to the catalogue to measure the local environmental density of these galaxies. This code counts the number of neighbours within a fixed search radius and a radial velocity range centered at each galaxy's radial velocity. A projected radius of 1.5 Mpc and a range of ± 2,500 km/s, both centered at the redshift of the target galaxy, were used to search and count all the neighbours of each galaxy in the catalogue. The neighbours were counted from the photometric catalogue of the SDSS-DR7 using photometric redshifts, to avoid incompleteness of the spectroscopic catalogue. The morphology of the galaxies in the catalogue was inferred by inverting previously found relations between subsamples of galaxies with visual morphology classification and their optical colours and concentration of light. The galaxies in the catalogue were matched to six

Some observational tests of a minimal galaxy formation model

NASA Astrophysics Data System (ADS)

Cohn, J. D.

2017-04-01

Dark matter simulations can serve as a basis for creating galaxy histories via the galaxy-dark matter connection. Here, one such model by Becker is implemented with several variations on three different dark matter simulations. Stellar mass and star formation rates are assigned to all simulation subhaloes at all times, using subhalo mass gain to determine stellar mass gain. The observational properties of the resulting galaxy distributions are compared to each other and observations for a range of redshifts from 0 to 2. Although many of the galaxy distributions seem reasonable, there are noticeable differences as simulations, subhalo mass gain definitions or subhalo mass definitions are altered, suggesting that the model should change as these properties are varied. Agreement with observations may improve by including redshift dependence in the added-by-hand random contribution to star formation rate. There appears to be an excess of faint quiescent galaxies as well (perhaps due in part to differing definitions of quiescence). The ensemble of galaxy formation histories for these models tend to have more scatter around their average histories (for a fixed final stellar mass) than the two more predictive and elaborate semi-analytic models of Guo et al. and Henriques et al., and require more basis fluctuations (using principal component analysis) to capture 90 per cent of the scatter around their average histories. The codes to plot model predictions (in some cases alongside observational data) are publicly available to test other mock catalogues at https://github.com/jdcphysics/validation/. Information on how to use these codes is in Appendix A.

Galaxy clustering dependence on the [O II] emission line luminosity in the local Universe

NASA Astrophysics Data System (ADS)

Favole, Ginevra; Rodríguez-Torres, Sergio A.; Comparat, Johan; Prada, Francisco; Guo, Hong; Klypin, Anatoly; Montero-Dorta, Antonio D.

2017-11-01

We study the galaxy clustering dependence on the [O II] emission line luminosity in the SDSS DR7 Main galaxy sample at mean redshift z ∼ 0.1. We select volume-limited samples of galaxies with different [O II] luminosity thresholds and measure their projected, monopole and quadrupole two-point correlation functions. We model these observations using the 1 h-1 Gpc MultiDark-Planck cosmological simulation and generate light cones with the SUrvey GenerAtoR algorithm. To interpret our results, we adopt a modified (Sub)Halo Abundance Matching scheme, accounting for the stellar mass incompleteness of the emission line galaxies. The satellite fraction constitutes an extra parameter in this model and allows to optimize the clustering fit on both small and intermediate scales (i.e. rp ≲ 30 h-1 Mpc), with no need of any velocity bias correction. We find that, in the local Universe, the [O II] luminosity correlates with all the clustering statistics explored and with the galaxy bias. This latter quantity correlates more strongly with the SDSS r-band magnitude than [O II] luminosity. In conclusion, we propose a straightforward method to produce reliable clustering models, entirely built on the simulation products, which provides robust predictions of the typical ELG host halo masses and satellite fraction values. The SDSS galaxy data, MultiDark mock catalogues and clustering results are made publicly available.

EGG: hatching a mock Universe from empirical prescriptions⋆

NASA Astrophysics Data System (ADS)

Schreiber, C.; Elbaz, D.; Pannella, M.; Merlin, E.; Castellano, M.; Fontana, A.; Bourne, N.; Boutsia, K.; Cullen, F.; Dunlop, J.; Ferguson, H. C.; Michałowski, M. J.; Okumura, K.; Santini, P.; Shu, X. W.; Wang, T.; White, C.

2017-06-01

This paper introduces EGG, the Empirical Galaxy Generator, a tool designed within the ASTRODEEP collaboration to generate mock galaxy catalogs for deep fields with realistic fluxes and simple morphologies. The simulation procedure is based exclusively on empirical prescriptions - rather than first principles - to provide the most accurate match with current observations at 0 galaxies can be either quiescent or star-forming, and used their stellar mass (M∗) and redshift (z) as the fundamental properties from which all the other observables can be statistically derived. Drawing z and M∗ from the observed galaxy stellar mass functions, a star-formation rate (SFR) is attributed to each galaxy from the tight SFR-M∗ main sequence, while dust attenuation, optical colors and simple disk plus bulge morphologies are obtained from empirical relations that we established from the high quality Hubble and Herschel observations from the CANDELS fields. Random scatter was introduced in each step to reproduce the observed distributions of each parameter. Based on these observables, an adequate panchromatic spectral energy distribution (SED) is selected for each galaxy and synthetic photometry is produced by integrating the redshifted SED in common broad-band filters. Finally, the mock galaxies are placed on the sky at random positions with a fixed angular two-point correlation function to implement basic clustering. The resulting flux catalogs reproduce accurately the observed number counts in all broad bands from the ultraviolet up to the sub-millimeter, and can be directly fed to image simulators such as SkyMaker. The images can then be used to test source extraction softwares and image-based techniques such as stacking. EGG is open-source, and is made available to the community on behalf of the ASTRODEEP collaboration, together with a set of pre-generated catalogs and images. http://cschreib.github.io/egg/ Full Table C.1 is only available at the

Brighter galaxy bias: underestimating the velocity dispersions of galaxy clusters

NASA Astrophysics Data System (ADS)

Old, L.; Gray, M. E.; Pearce, F. R.

2013-09-01

We study the systematic bias introduced when selecting the spectroscopic redshifts of brighter cluster galaxies to estimate the velocity dispersion of galaxy clusters from both simulated and observational galaxy catalogues. We select clusters with Ngal ≥ 50 at five low-redshift snapshots from the publicly available De Lucia & Blaziot semi-analytic model galaxy catalogue. Clusters are also selected from the Tempel Sloan Digital Sky Survey Data Release 8 groups and clusters catalogue across the redshift range 0.021 ≤ z ≤ 0.098. We employ various selection techniques to explore whether the velocity dispersion bias is simply due to a lack of dynamical information or is the result of an underlying physical process occurring in the cluster, for example, dynamical friction experienced by the brighter cluster members. The velocity dispersions of the parent dark matter (DM) haloes are compared to the galaxy cluster dispersions and the stacked distribution of DM particle velocities is examined alongside the corresponding galaxy velocity distribution. We find a clear bias between the halo and the semi-analytic galaxy cluster velocity dispersion on the order of σgal/σDM ˜ 0.87-0.95 and a distinct difference in the stacked galaxy and DM particle velocities distribution. We identify a systematic underestimation of the velocity dispersions when imposing increasing absolute I-band magnitude limits. This underestimation is enhanced when using only the brighter cluster members for dynamical analysis on the order of 5-35 per cent, indicating that dynamical friction is a serious source of bias when using galaxy velocities as tracers of the underlying gravitational potential. In contrast to the literature we find that the resulting bias is not only halo mass dependent but also that the nature of the dependence changes according to the galaxy selection strategy. We make a recommendation that, in the realistic case of limited availability of spectral observations, a strictly

Photometric redshift requirements for lens galaxies in galaxy-galaxy lensing analyses

NASA Astrophysics Data System (ADS)

Nakajima, R.; Mandelbaum, R.; Seljak, U.; Cohn, J. D.; Reyes, R.; Cool, R.

2012-03-01

Weak gravitational lensing is a valuable probe of galaxy formation and cosmology. Here we quantify the effects of using photometric redshifts (photo-z) in galaxy-galaxy lensing, for both sources and lenses, both for the immediate goal of using galaxies with photo-z as lenses in the Sloan Digital Sky Survey (SDSS) and as a demonstration of methodology for large, upcoming weak lensing surveys that will by necessity be dominated by lens samples with photo-z. We calculate the bias in the lensing mass calibration as well as consequences for absolute magnitude (i.e. k-corrections) and stellar mass estimates for a large sample of SDSS Data Release 8 (DR8) galaxies. The redshifts are obtained with the template-based photo-z code ZEBRA on the SDSS DR8 ugriz photometry. We assemble and characterize the calibration samples (˜9000 spectroscopic redshifts from four surveys) to obtain photometric redshift errors and lensing biases corresponding to our full SDSS DR8 lens and source catalogues. Our tests of the calibration sample also highlight the impact of observing conditions in the imaging survey when the spectroscopic calibration covers a small fraction of its footprint; atypical imaging conditions in calibration fields can lead to incorrect conclusions regarding the photo-z of the full survey. For the SDSS DR8 catalogue, we find σΔz/(1+z)= 0.096 and 0.113 for the lens and source catalogues, with flux limits of r= 21 and 21.8, respectively. The photo-z bias and scatter is a function of photo-z and template types, which we exploit to apply photo-z quality cuts. By using photo-z rather than spectroscopy for lenses, dim blue galaxies and L* galaxies up to z˜ 0.4 can be used as lenses, thus expanding into unexplored areas of parameter space. We also explore the systematic uncertainty in the lensing signal calibration when using source photo-z, and both lens and source photo-z; given the size of existing training samples, we can constrain the lensing signal calibration (and

Lensing is low: cosmology, galaxy formation or new physics?

NASA Astrophysics Data System (ADS)

Leauthaud, Alexie; Saito, Shun; Hilbert, Stefan; Barreira, Alexandre; More, Surhud; White, Martin; Alam, Shadab; Behroozi, Peter; Bundy, Kevin; Coupon, Jean; Erben, Thomas; Heymans, Catherine; Hildebrandt, Hendrik; Mandelbaum, Rachel; Miller, Lance; Moraes, Bruno; Pereira, Maria E. S.; Rodríguez-Torres, Sergio A.; Schmidt, Fabian; Shan, Huan-Yuan; Viel, Matteo; Villaescusa-Navarro, Francisco

2017-05-01

We present high signal-to-noise galaxy-galaxy lensing measurements of the Baryon Oscillation Spectroscopic Survey constant mass (CMASS) sample using 250 deg2 of weak-lensing data from Canada-France-Hawaii Telescope Lensing Survey and Canada-France-Hawaii Telescope Stripe 82 Survey. We compare this signal with predictions from mock catalogues trained to match observables including the stellar mass function and the projected and two-dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy-halo connection, robustly predicts a lensing signal that is 20-40 per cent larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of S_8=σ _8 \\sqrt{Ω _m/0.3} compared to Planck Collaboration XIII reconciles the lensing with clustering. However, given the scale of our measurement (r < 10 h-1 Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos and modifications to general relativity on ΔΣ and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy-halo connection, the effect of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.

Properties and spatial distribution of galaxy superclusters

NASA Astrophysics Data System (ADS)

Liivamägi, Lauri Juhan

2017-01-01

Astronomy is a science that can offer plenty of unforgettable imagery, and the large-scale distribution of galaxies is no exception. Among the first features the viewer's eye is likely to be drawn to, are large concentrations of galaxies - galaxy superclusters, contrasting to the seemingly empty regions beside them. Superclusters can extend from tens to over hundred megaparsecs, they contain from hundreds to thousands of galaxies, and many galaxy groups and clusters. Unlike galaxy clusters, superclusters are clearly unrelaxed systems, not gravitationally bound as crossing times exceed the age of the universe, and show little to no radial symmetry. Superclusters, as part of the large-scale structure, are sensitive to the initial power spectrum and the following evolution. They are massive enough to leave an imprint on the cosmic microwave background radiation. Superclusters can also provide an unique environment for their constituent galaxies and galaxy clusters. In this study we used two different observational and one simulated galaxy samples to create several catalogues of structures that, we think, correspond to what are generally considered galaxy superclusters. Superclusters were delineated as continuous over-dense regions in galaxy luminosity density fields. When calculating density fields several corrections were applied to remove small-scale redshift distortions and distance-dependent selection effects. Resulting catalogues of objects display robust statistical properties, showing that flux-limited galaxy samples can be used to create nearly volume-limited catalogues of superstructures. Generally, large superclusters can be regarded as massive, often branching filamentary structures, that are mainly characterised by their length. Smaller superclusters, on the other hand, can display a variety of shapes. Spatial distribution of superclusters shows large-scale variations, with high-density concentrations often found in semi-regularly spaced groups. Future

The effects of assembly bias on the inference of matter clustering from galaxy-galaxy lensing and galaxy clustering

NASA Astrophysics Data System (ADS)

McEwen, Joseph E.; Weinberg, David H.

2018-07-01

The combination of galaxy-galaxy lensing and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modelling can extend the approach down to non-linear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with the large-scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older haloes affects the cutoff of the mean occupation function ⟨Ncen(Mmin)⟩ for central galaxies, with haloes in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment-dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, rgm(r) ≡ ξgm(r) . [ξmm(r)ξgg(r)]-1/2, is insensitive to assembly bias on scales r ≳ 1 h-1 Mpc, even though ξgm(r) and ξgg(r) are both affected individually. We can therefore recover the correct ξmm(r) from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For Mr ≤ -19 or Mr ≤ -20 samples the recovery of ξmm(r) is accurate to 2 per cent or better. For a sample of red Mr ≤ -20 galaxies, we achieve 2 per cent recovery at r ≳ 2 h-1 Mpc with EDHOD modelling but lower accuracy at smaller scales or with a standard HOD fit. Most of our mock galaxy samples are consistent with rgm = 1 down to r = 1 h-1 Mpc, to within the uncertainties set by our finite simulation volume.

The effects of assembly bias on the inference of matter clustering from galaxy-galaxy lensing and galaxy clustering

NASA Astrophysics Data System (ADS)

McEwen, Joseph E.; Weinberg, David H.

2018-04-01

The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, rgm(r) ≡ ξgm(r) . [ξmm(r)ξgg(r)]-1/2, is insensitive to assembly bias on scales r ≳ 1 h^{-1} Mpc, even though ξgm(r) and ξgg(r) are both affected individually. We can therefore recover the correct ξmm(r) from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For Mr ≤ -19 or Mr ≤ -20 samples the recovery of ξmm(r) is accurate to 2% or better. For a sample of red Mr ≤ -20 galaxies we achieve 2% recovery at r ≳ 2 h^{-1} Mpc with EDHOD modeling but lower accuracy at smaller scales or with a standard HOD fit. Most of our mock galaxy samples are consistent with rgm = 1 down to r = 1h-1Mpc, to within the uncertainties set by our finite simulation volume.

MULTIDARK-GALAXIES: data release and first results

NASA Astrophysics Data System (ADS)

Knebe, Alexander; Stoppacher, Doris; Prada, Francisco; Behrens, Christoph; Benson, Andrew; Cora, Sofia A.; Croton, Darren J.; Padilla, Nelson D.; Ruiz, Andrés N.; Sinha, Manodeep; Stevens, Adam R. H.; Vega-Martínez, Cristian A.; Behroozi, Peter; Gonzalez-Perez, Violeta; Gottlöber, Stefan; Klypin, Anatoly A.; Yepes, Gustavo; Enke, Harry; Libeskind, Noam I.; Riebe, Kristin; Steinmetz, Matthias

2018-03-01

We present the public release of the MULTIDARK-GALAXIES: three distinct galaxy catalogues derived from one of the Planck cosmology MULTIDARK simulations (i.e. MDPL2, with a volume of (1 h-1 Gpc)3 and mass resolution of 1.5 × 109 h-1 M⊙) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three models and their conformity with observational data for a selection of fundamental properties of galaxies like stellar mass function, star formation rate, cold gas fractions, and metallicities - noting that they sometimes perform differently reflecting model designs and calibrations. We have further selected galaxy subsamples of the catalogues by number densities in stellar mass, cold gas mass, and star formation rate in order to study the clustering statistics of galaxies. We show that despite different treatment of orphan galaxies, i.e. galaxies that lost their dark-matter host halo due to the finite-mass resolution of the N-body simulation or tidal stripping, the clustering signal is comparable, and reproduces the observations in all three models - in particular when selecting samples based upon stellar mass. Our catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by ongoing and future photometric and redshift surveys. All model data consisting of a range of galaxy properties - including broad-band SDSS magnitudes - are publicly available.

ICE-COLA: towards fast and accurate synthetic galaxy catalogues optimizing a quasi-N-body method

NASA Astrophysics Data System (ADS)

Izard, Albert; Crocce, Martin; Fosalba, Pablo

2016-07-01

Next generation galaxy surveys demand the development of massive ensembles of galaxy mocks to model the observables and their covariances, what is computationally prohibitive using N-body simulations. COmoving Lagrangian Acceleration (COLA) is a novel method designed to make this feasible by following an approximate dynamics but with up to three orders of magnitude speed-ups when compared to an exact N-body. In this paper, we investigate the optimization of the code parameters in the compromise between computational cost and recovered accuracy in observables such as two-point clustering and halo abundance. We benchmark those observables with a state-of-the-art N-body run, the MICE Grand Challenge simulation. We find that using 40 time-steps linearly spaced since zI ˜ 20, and a force mesh resolution three times finer than that of the number of particles, yields a matter power spectrum within 1 per cent for k ≲ 1 h Mpc-1 and a halo mass function within 5 per cent of those in the N-body. In turn, the halo bias is accurate within 2 per cent for k ≲ 0.7 h Mpc-1 whereas, in redshift space, the halo monopole and quadrupole are within 4 per cent for k ≲ 0.4 h Mpc-1. These results hold for a broad range in redshift (0 < z < 1) and for all halo mass bins investigated (M > 1012.5 h-1 M⊙). To bring accuracy in clustering to one per cent level we study various methods that re-calibrate halo masses and/or velocities. We thus propose an optimized choice of COLA code parameters as a powerful tool to optimally exploit future galaxy surveys.

On the nature and correction of the spurious S-wise spiral galaxy winding bias in Galaxy Zoo 1

NASA Astrophysics Data System (ADS)

Hayes, Wayne B.; Davis, Darren; Silva, Pedro

2017-04-01

The Galaxy Zoo 1 catalogue displays a bias towards the S-wise winding direction in spiral galaxies, which has yet to be explained. The lack of an explanation confounds our attempts to verify the Cosmological Principle, and has spurred some debate as to whether a bias exists in the real Universe. The bias manifests not only in the obvious case of trying to decide if the universe as a whole has a winding bias, but also in the more insidious case of selecting which Galaxies to include in a winding direction survey. While the former bias has been accounted for in a previous image-mirroring study, the latter has not. Furthermore, the bias has never been corrected in the GZ1 catalogue, as only a small sample of the GZ1 catalogue was reexamined during the mirror study. We show that the existing bias is a human selection effect rather than a human chirality bias. In effect, the excess S-wise votes are spuriously 'stolen' from the elliptical and edge-on-disc categories, not the Z-wise category. Thus, when selecting a set of spiral galaxies by imposing a threshold T so that max (PS, PZ) > T or PS + PZ > T, we spuriously select more S-wise than Z-wise galaxies. We show that when a provably unbiased machine selects which galaxies are spirals independent of their chirality, the S-wise surplus vanishes, even if humans still determine the chirality. Thus, when viewed across the entire GZ1 sample (and by implication, the Sloan catalogue), the winding direction of arms in spiral galaxies as viewed from Earth is consistent with the flip of a fair coin.

Modelling and interpreting spectral energy distributions of galaxies with BEAGLE

NASA Astrophysics Data System (ADS)

Chevallard, Jacopo; Charlot, Stéphane

2016-10-01

We present a new-generation tool to model and interpret spectral energy distributions (SEDs) of galaxies, which incorporates in a consistent way the production of radiation and its transfer through the interstellar and intergalactic media. This flexible tool, named BEAGLE (for BayEsian Analysis of GaLaxy sEds), allows one to build mock galaxy catalogues as well as to interpret any combination of photometric and spectroscopic galaxy observations in terms of physical parameters. The current version of the tool includes versatile modelling of the emission from stars and photoionized gas, attenuation by dust and accounting for different instrumental effects, such as spectroscopic flux calibration and line spread function. We show a first application of the BEAGLE tool to the interpretation of broad-band SEDs of a published sample of ˜ 10^4 galaxies at redshifts 0.1 ≲ z ≲ 8. We find that the constraints derived on photometric redshifts using this multipurpose tool are comparable to those obtained using public, dedicated photometric-redshift codes and quantify this result in a rigorous statistical way. We also show how the post-processing of BEAGLE output data with the PYTHON extension PYP-BEAGLE allows the characterization of systematic deviations between models and observations, in particular through posterior predictive checks. The modular design of the BEAGLE tool allows easy extensions to incorporate, for example, the absorption by neutral galactic and circumgalactic gas, and the emission from an active galactic nucleus, dust and shock-ionized gas. Information about public releases of the BEAGLE tool will be maintained on http://www.jacopochevallard.org/beagle.

The dipole anisotropy of AllWISE galaxies

NASA Astrophysics Data System (ADS)

Rameez, M.; Mohayaee, R.; Sarkar, S.; Colin, J.

2018-06-01

We determine the dipole in the WISE (Wide Infrared Satellite Explorer) galaxy catalogue. After reducing star contamination to < 0.1 per cent by rejecting sources with high apparent motion and those close to the Galactic plane, we eliminate low redshift sources to suppress the non-kinematic, clustering dipole. We remove sources within ±5° of the supergalactic plane, as well as those within 1ʺ of 2MRS sources at redshift z < 0.03. We enforce cuts on the source angular extent to preferentially select distant ones. As we progress along these steps, the dipole converges in direction to within 5° of the Cosmic Microwave Background (CMB) dipole and its magnitude also progressively reduces but stabilizes at ˜0.012, corresponding to a velocity >1000 km s-1 if it is solely of kinematic origin. However, previous studies have shown that only ˜ 70 per cent of the velocity of the Local Group as inferred from the CMB dipole is due to sources at z < 0.03. We examine the Dark Sky simulations to quantify the prevalence of such environments and find that <2.1 per cent of Milky Way-like observers in a ΛCDM universe should observe the bulk flow (>240 km s-1 extending to z > 0.03) that we do. We construct mock catalogues in the neighbourhood of such peculiar observers in order to mimic our final galaxy selection and quantify the residual clustering dipole. After subtracting this, the remaining dipole is 0.0048 ± 0.0022, corresponding to a velocity of 420 ± 213 km s-1, which is consistent with the CMB. However, the sources (at z > 0.03) of such a large clustering dipole remain to be identified.

The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters

NASA Astrophysics Data System (ADS)

Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

2016-12-01

We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark matter haloes of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 and 15. Our directly measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. for the BOSS LOWZ sample and White et al. for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fitting alpha-index of 0.91 ± 0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. and Parejko et al. In summary, our study provides independent support for the HOD models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

Box/peanut and bar structures in edge-on and face-on nearby galaxies in the Sloan Digital Sky Survey - I. Catalogue

NASA Astrophysics Data System (ADS)

Yoshino, Akira; Yamauchi, Chisato

2015-02-01

We investigate box/peanut and bar structures in image data of edge-on and face-on nearby galaxies taken from the Sloan Digital Sky Survey (SDSS) to present catalogues containing the surface brightness parameters and the morphology classification. About 1700 edge-on galaxies and 2600 face-on galaxies are selected from SDSS DR7 in the g, r and i-bands. The images of each galaxy are fitted with the model of two-dimensional surface brightness of the Sérsic bulge and exponential disk. After removing some irregular data, the box/peanut, bar and other structures are easily distinguished by eye using residual (observed minus model) images. We find 292 box/peanut structures in the 1329 edge-on samples and 630 bar structures in 1890 face-on samples in the i-band, after removing some irregular data. The fraction of box/peanut galaxies is about 22 per cent against the edge-on samples, and that of bar galaxies is about 33 per cent (about 50 per cent if 629 elliptical galaxies are removed) against the face-on samples. Furthermore the strengths of the box/peanuts and bars are evaluated as strong, standard or weak. We find that the strength increases slightly with increasing B/T (bulge-to-total flux ratio), and that the fraction of box/peanuts is generally about a half of that of bars, irrespective of the strength and B/T. Our result supports the idea that a box/peanut is a bar seen edge-on.

Dark Energy Survey Year 1 Results: Weak Lensing Shape Catalogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuntz, J.; et al.

We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 square degrees with a median redshift ofmore » $0.59$. The catalogues cover two main fields: Stripe 82, and an area overlapping the South Pole Telescope survey region. We describe our data analysis process and in particular our shape measurement using two independent shear measurement pipelines, METACALIBRATION and IM3SHAPE. The METACALIBRATION catalogue uses a Gaussian model with an innovative internal calibration scheme, and was applied to $riz$-bands, yielding 34.8M objects. The IM3SHAPE catalogue uses a maximum-likelihood bulge/disc model calibrated using simulations, and was applied to $r$-band data, yielding 21.9M objects. Both catalogues pass a suite of null tests that demonstrate their fitness for use in weak lensing science. We estimate the 1$$\\sigma$$ uncertainties in multiplicative shear calibration to be $0.013$ and $0.025$ for the METACALIBRATION and IM3SHAPE catalogues, respectively.« less

Cosmology with XMM galaxy clusters: the X-CLASS/GROND catalogue and photometric redshifts

NASA Astrophysics Data System (ADS)

Ridl, J.; Clerc, N.; Sadibekova, T.; Faccioli, L.; Pacaud, F.; Greiner, J.; Krühler, T.; Rau, A.; Salvato, M.; Menzel, M.-L.; Steinle, H.; Wiseman, P.; Nandra, K.; Sanders, J.

2017-06-01

The XMM Cluster Archive Super Survey (X-CLASS) is a serendipitously detected X-ray-selected sample of 845 galaxy clusters based on 2774 XMM archival observations and covering an approximately 90 deg2 spread across the high-Galactic latitude (|b| > 20°) sky. The primary goal of this survey is to produce a well-selected sample of galaxy clusters on which cosmological analyses can be performed. This paper presents the photometric redshift follow-up of a high signal-to-noise ratio subset of 265 of these clusters with declination δ < +20° with Gamma-Ray Burst Optical and Near-Infrared Detector (GROND), a 7-channel (grizJHK) simultaneous imager on the MPG 2.2-m telescope at the ESO La Silla Observatory. We use a newly developed technique based on the red sequence colour-redshift relation, enhanced with information coming from the X-ray detection to provide photometric redshifts for this sample. We determine photometric redshifts for 232 clusters, finding a median redshift of z = 0.39 with an accuracy of Δz = 0.02(1 + z) when compared to a sample of 76 spectroscopically confirmed clusters. We also compute X-ray luminosities for the entire sample and find a median bolometric luminosity of 7.2 × 1043 erg s-1 and a median temperature of 2.9 keV. We compare our results to those of the XMM-XCS and XMM-XXL surveys, finding good agreement in both samples. The X-CLASS catalogue is available online at http://xmm-lss.in2p3.fr:8080/l4sdb/.

Triggering and Quenching: simulations and mock observations of Active Galactic Nuclei and their hosts

NASA Astrophysics Data System (ADS)

Choi, Ena

2015-10-01

The lives of galaxies and their supermassive black holes (SMBH) are probably intimately linked. Deep multi-wavelength surveys with HST are now providing detailed imaging of a statistically robust sample of obscured and unobscured AGN hosts, along with control samples of inactive galaxies, giving us an unprecedented opportunity to study the relationship between AGN and their hosts. However, so far these observations have uncovered more puzzles than they have resolved. Although mergers are considered a promising triggering mechanism for AGN activity, numerous studies have shown that AGN hosts are no more likely to appear morphologically disturbed than inactive galaxies. Studies of whether AGN hosts exhibit enhanced or suppressed star formation have also yielded conflicting results. We propose to run a suite of state-of-the-art simulations to study the AGN-host galaxy connection. These simulations will be post-processed with a radiative transfer code, a sub-grid model for torus-scale obscuration, and short timescale AGN variability. Using mock images created from the simulations, we will study the predicted morphologies and stellar populations of AGN hosts and normal galaxies with similar stellar masses. We will use our simulations to address two major science questions: (1) how is SMBH growth fueled and fed, and what triggers rapid feeding, and (2) how does AGN feedback regulate BH growth and the growth of the host galaxy? In addition, we will release our simulation outputs and mock images and catalogs to the community through MAST.

An automatic taxonomy of galaxy morphology using unsupervised machine learning

NASA Astrophysics Data System (ADS)

Hocking, Alex; Geach, James E.; Sun, Yi; Davey, Neil

2018-01-01

We present an unsupervised machine learning technique that automatically segments and labels galaxies in astronomical imaging surveys using only pixel data. Distinct from previous unsupervised machine learning approaches used in astronomy we use no pre-selection or pre-filtering of target galaxy type to identify galaxies that are similar. We demonstrate the technique on the Hubble Space Telescope (HST) Frontier Fields. By training the algorithm using galaxies from one field (Abell 2744) and applying the result to another (MACS 0416.1-2403), we show how the algorithm can cleanly separate early and late type galaxies without any form of pre-directed training for what an 'early' or 'late' type galaxy is. We then apply the technique to the HST Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) fields, creating a catalogue of approximately 60 000 classifications. We show how the automatic classification groups galaxies of similar morphological (and photometric) type and make the classifications public via a catalogue, a visual catalogue and galaxy similarity search. We compare the CANDELS machine-based classifications to human-classifications from the Galaxy Zoo: CANDELS project. Although there is not a direct mapping between Galaxy Zoo and our hierarchical labelling, we demonstrate a good level of concordance between human and machine classifications. Finally, we show how the technique can be used to identify rarer objects and present lensed galaxy candidates from the CANDELS imaging.

An extensive photometric catalogue of CALIFA galaxies

NASA Astrophysics Data System (ADS)

Gilhuly, Colleen; Courteau, Stéphane

2018-06-01

We present an extensive compendium of photometrically determined structural properties for all Calar Alto Legacy Integral Field spectroscopy Area (CALIFA) galaxies in the third data release (DR3). We exploit Sloan Digital Sky Survey (SDSS) images in order to extract one-dimensional (1D) gri surface brightness profiles for all CALIFA DR3 galaxies. We also derive a variety of non-parametric quantities and parametric models fitted to 1D i-band profiles. The galaxy images are decomposed using the 2D bulge-disc decomposition programs IMFIT and GALFIT. The relative performance and merit of our 1D and 2D modelling approaches are assessed. Where possible, we compare and augment our photometry with existing measurements from the literature. Close agreement is generally found with the studies of Walcher et al. and Méndez-Abreu et al., though some significant differences exist. Various structural metrics are also highlighted on account of their tight dispersion against an independent variable, such as the circular velocity.

Measures of galaxy environment - I. What is 'environment'?

NASA Astrophysics Data System (ADS)

Muldrew, Stuart I.; Croton, Darren J.; Skibba, Ramin A.; Pearce, Frazer R.; Ann, Hong Bae; Baldry, Ivan K.; Brough, Sarah; Choi, Yun-Young; Conselice, Christopher J.; Cowan, Nicolas B.; Gallazzi, Anna; Gray, Meghan E.; Grützbauch, Ruth; Li, I.-Hui; Park, Changbom; Pilipenko, Sergey V.; Podgorzec, Bret J.; Robotham, Aaron S. G.; Wilman, David J.; Yang, Xiaohu; Zhang, Youcai; Zibetti, Stefano

2012-01-01

The influence of a galaxy's environment on its evolution has been studied and compared extensively in the literature, although differing techniques are often used to define environment. Most methods fall into two broad groups: those that use nearest neighbours to probe the underlying density field and those that use fixed apertures. The differences between the two inhibit a clean comparison between analyses and leave open the possibility that, even with the same data, different properties are actually being measured. In this work, we apply 20 published environment definitions to a common mock galaxy catalogue constrained to look like the local Universe. We find that nearest-neighbour-based measures best probe the internal densities of high-mass haloes, while at low masses the interhalo separation dominates and acts to smooth out local density variations. The resulting correlation also shows that nearest-neighbour galaxy environment is largely independent of dark matter halo mass. Conversely, aperture-based methods that probe superhalo scales accurately identify high-density regions corresponding to high-mass haloes. Both methods show how galaxies in dense environments tend to be redder, with the exception of the largest apertures, but these are the strongest at recovering the background dark matter environment. We also warn against using photometric redshifts to define environment in all but the densest regions. When considering environment, there are two regimes: the 'local environment' internal to a halo best measured with nearest neighbour and 'large-scale environment' external to a halo best measured with apertures. This leads to the conclusion that there is no universal environment measure and the most suitable method depends on the scale being probed.

Improving galaxy morphologies for SDSS with Deep Learning

NASA Astrophysics Data System (ADS)

Domínguez Sánchez, H.; Huertas-Company, M.; Bernardi, M.; Tuccillo, D.; Fischer, J. L.

2018-05-01

We present a morphological catalogue for ˜670 000 galaxies in the Sloan Digital Sky Survey in two flavours: T-type, related to the Hubble sequence, and Galaxy Zoo 2 (GZ2 hereafter) classification scheme. By combining accurate existing visual classification catalogues with machine learning, we provide the largest and most accurate morphological catalogue up to date. The classifications are obtained with Deep Learning algorithms using Convolutional Neural Networks (CNNs). We use two visual classification catalogues, GZ2 and Nair & Abraham (2010), for training CNNs with colour images in order to obtain T-types and a series of GZ2 type questions (disc/features, edge-on galaxies, bar signature, bulge prominence, roundness, and mergers). We also provide an additional probability enabling a separation between pure elliptical (E) from S0, where the T-type model is not so efficient. For the T-type, our results show smaller offset and scatter than previous models trained with support vector machines. For the GZ2 type questions, our models have large accuracy (>97 per cent), precision and recall values (>90 per cent), when applied to a test sample with the same characteristics as the one used for training. The catalogue is publicly released with the paper.

CMB-galaxy correlation in Unified Dark Matter scalar field cosmologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertacca, Daniele; Bartolo, Nicola; Matarrese, Sabino

We present an analysis of the cross-correlation between the CMB and the large-scale structure (LSS) of the Universe in Unified Dark Matter (UDM) scalar field cosmologies. We work out the predicted cross-correlation function in UDM models, which depends on the speed of sound of the unified component, and compare it with observations from six galaxy catalogues (NVSS, HEAO, 2MASS, and SDSS main galaxies, luminous red galaxies, and quasars). We sample the value of the speed of sound and perform a likelihood analysis, finding that the UDM model is as likely as the ΛCDM, and is compatible with observations for amore » range of values of c{sub ∞} (the value of the sound speed at late times) on which structure formation depends. In particular, we obtain an upper bound of c{sub ∞}{sup 2} ≤ 0.009 at 95% confidence level, meaning that the ΛCDM model, for which c{sub ∞}{sup 2} = 0, is a good fit to the data, while the posterior probability distribution peaks at the value c{sub ∞}{sup 2} = 10{sup −4} . Finally, we study the time dependence of the deviation from ΛCDM via a tomographic analysis using a mock redshift distribution and we find that the largest deviation is for low-redshift sources, suggesting that future low-z surveys will be best suited to constrain UDM models.« less

powerbox: Arbitrarily structured, arbitrary-dimension boxes and log-normal mocks

NASA Astrophysics Data System (ADS)

Murray, Steven G.

2018-05-01

powerbox creates density grids (or boxes) with an arbitrary two-point distribution (i.e. power spectrum). The software works in any number of dimensions, creates Gaussian or Log-Normal fields, and measures power spectra of output fields to ensure consistency. The primary motivation for creating the code was the simple creation of log-normal mock galaxy distributions, but the methodology can be used for other applications.

On the evolution of the star formation rate function of massive galaxies: constraints at 0.4 < z < 1.8 from the GOODS-MUSIC catalogue

NASA Astrophysics Data System (ADS)

Fontanot, Fabio; Cristiani, Stefano; Santini, Paola; Fontana, Adriano; Grazian, Andrea; Somerville, Rachel S.

2012-03-01

We study the evolution of the star formation rate function (SFRF) of massive (M★ > 1010 M⊙) galaxies over the 0.4 < z < 1.8 redshift range and its implications for our understanding of the physical processes responsible for galaxy evolution. We use multiwavelength observations included in the Great Observatories Origins Deep Survey-Multiwavelength Southern Infrared Catalog (GOODS-MUSIC) catalogue, which provides a suitable coverage of the spectral region from 0.3 to 24 ?m and either spectroscopic or photometric redshifts for each object. Individual SFRs have been obtained by combining ultraviolet and 24-?m observations, when the latter were available. For all other sources a 'spectral energy distribution (SED) fitting' SFR estimate has been considered. We then define a stellar mass limited sample, complete in the M★ > 1010 M⊙ range and determine the SFRF using the 1/Vmax algorithm. We thus define simulated galaxy catalogues based on the predictions of three different state-of-the-art semi-analytical models (SAMs) of galaxy formation and evolution, and compare them with the observed SFRF. We show that the theoretical SFRFs are well described by a double power law functional form and its redshift evolution is approximated with high accuracy by a pure evolution of the typical SFR (SFR★). We find good agreement between model predictions and the high-SFR end of the SFRF, when the observational errors on the SFR are taken into account. However, the observational SFRF is characterized by a double-peaked structure, which is absent in its theoretical counterparts. At z > 1.0 the observed SFRF shows a relevant density evolution, which is not reproduced by SAMs, due to the well-known overprediction of intermediate-mass galaxies at z˜ 2. SAMs are thus able to reproduce the most intense SFR events observed in the GOODS-MUSIC sample and their redshift distribution. At the same time, the agreement at the low-SFR end is poor: all models overpredict the space density of

A Ks-band-selected catalogue of objects in the ALHAMBRA survey

NASA Astrophysics Data System (ADS)

Nieves-Seoane, L.; Fernandez-Soto, A.; Arnalte-Mur, P.; Molino, A.; Stefanon, M.; Ferreras, I.; Ascaso, B.; Ballesteros, F. J.; Cristóbal-Hornillos, D.; López-Sanjuán, C.; Hurtado-Gil, Ll.; Márquez, I.; Masegosa, J.; Aguerri, J. A. L.; Alfaro, E.; Aparicio-Villegas, T.; Benítez, N.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; González Delgado, R. M.; Husillos, C.; Infante, L.; Martínez, V. J.; Moles, M.; Olmo, A. del; Perea, J.; Pović, M.; Prada, F.; Quintana, J. M.; Troncoso-Iribarren, P.; Viironen, K.

2017-02-01

The original ALHAMBRA catalogue contained over 400 000 galaxies selected using a synthetic F814W image, to the magnitude limit AB(F814W) ≈ 24.5. Given the photometric redshift depth of the ALHAMBRA multiband data ( = 0.86) and the approximately I-band selection, there is a noticeable bias against red objects at moderate redshift. We avoid this bias by creating a new catalogue selected in the Ks band. This newly obtained catalogue is certainly shallower in terms of apparent magnitude, but deeper in terms of redshift, with a significant population of red objects at z > 1. We select objects using the Ks band images, which reach an approximate AB magnitude limit Ks ≈ 22. We generate masks and derive completeness functions to characterize the sample. We have tested the quality of the photometry and photometric redshifts using both internal and external checks. Our final catalogue includes ≈95 000 sources down to Ks ≈ 22, with a significant tail towards high redshift. We have checked that there is a large sample of objects with spectral energy distributions that correspond to that of massive, passively evolving galaxies at z > 1, reaching as far as z ≈ 2.5. We have tested the possibility of combining our data with deep infrared observations at longer wavelengths, particularly Spitzer IRAC data.

The Planck Catalogue of Galactic Cold Clumps : PGCC

NASA Astrophysics Data System (ADS)

Montier, L.

The Planck satellite has provided an unprecedented view of the submm sky, allowing us to search for the dust emission of Galactic cold sources. Combining Planck-HFI all-sky maps in the high frequency channels with the IRAS map at 100um, we built the Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results. XXVIII), counting 13188 sources distributed over the whole sky, and following mainly the Galactic structures at low and intermediate latitudes. This is the first all-sky catalogue of Galactic cold sources obtained with a single instrument at this resolution and sensitivity, which opens a new window on star-formation processes in our Galaxy.

High-redshift galaxy populations and their descendants

NASA Astrophysics Data System (ADS)

Guo, Qi; White, Simon D. M.

2009-06-01

We study predictions in the concordance Λ cold dark matter cosmology for the abundance and clustering of high-redshift galaxies and for the properties of their descendants. We focus on three high-redshift populations: Lyman break galaxies (LBGs) at z ~ 3, optically selected star-forming galaxies at z ~ 2 (BXs) and distant red galaxies (DRGs) at z ~ 2. We select galaxies from mock catalogues based on the Millennium Simulation using the observational colour and apparent magnitude criteria. With plausible dust assumptions, our galaxy formation model can simultaneously reproduce the abundances, redshift distributions and clustering of all three observed populations. The star formation rates (SFRs) of model LBGs and BXs are lower than those quoted for the real samples, reflecting differing initial mass functions and scatter in model dust properties. About 85 per cent of model galaxies selected as DRGs are star forming, with SFRs in the range 1 to ~100Msolaryr-1. Model LBGs, BXs and DRGs together account for less than half of all star formation over the range 1.5 < z < 3.2; many massive, star-forming galaxies are predicted to be too heavily obscured to appear in these populations. Model BXs have metallicities which agree roughly with observation, but model LBGs are only slightly more metal poor, in disagreement with recent observational results. The model galaxies are predominantly disc dominated. Stellar masses for LBGs and BXs are ~109.9Msolar, and for DRGs are ~1010.7Msolar. Only about 30 per cent of model galaxies with M* > 1011Msolar are classified as LBGs or BXs at the relevant redshifts, while 65 per cent are classified as DRGs. Almost all model LBGs and BXs are the central galaxies of their dark haloes, but fewer than half of the haloes of any given mass have an LBG or BX central galaxy. Half of all LBG descendants at z = 2 would be identified as BXs, but very few as DRGs. Clustering increases with decreasing redshift for descendants of all three populations

VizieR Online Data Catalog: Asiago Supernova Catalogue (Version 2008-Mar)

NASA Astrophysics Data System (ADS)

Barbon, R.; Buondi, V.; Cappellaro, E.; Turatto, M.

2008-02-01

This catalogue supersedes the previous version by Barbon et al. (1999A&AS..139..531B, Cat. II/227), and contains data about the supernovae observed since 1895 and their parent galaxies until the beginning of 2008. In addition to the list of newly discovered SNe, the literature has been searched for new information on past SNe as well. The data for the parent galaxies have also been homogenized. (1 data file).

Nebula observations. Catalogues and archive of photoplates

NASA Astrophysics Data System (ADS)

Shlyapnikov, A. A.; Smirnova, M. A.; Elizarova, N. V.

2017-12-01

A process of data systematization based on "Academician G.A. Shajn's Plan" for studying the Galaxy structure related to nebula observations is considered. The creation of digital versions of catalogues of observations and publications is described, as well as their presentation in HTML, VOTable and AJS formats and basic principles of work in the interactive application of International Virtual Observatory the Aladin Sky Atlas.

Reconstruction of halo power spectrum from redshift-space galaxy distribution: cylinder-grouping method and halo exclusion effect

NASA Astrophysics Data System (ADS)

Okumura, Teppei; Takada, Masahiro; More, Surhud; Masaki, Shogo

2017-07-01

The peculiar velocity field measured by redshift-space distortions (RSD) in galaxy surveys provides a unique probe of the growth of large-scale structure. However, systematic effects arise when including satellite galaxies in the clustering analysis. Since satellite galaxies tend to reside in massive haloes with a greater halo bias, the inclusion boosts the clustering power. In addition, virial motions of the satellite galaxies cause a significant suppression of the clustering power due to non-linear RSD effects. We develop a novel method to recover the redshift-space power spectrum of haloes from the observed galaxy distribution by minimizing the contamination of satellite galaxies. The cylinder-grouping method (CGM) we study effectively excludes satellite galaxies from a galaxy sample. However, we find that this technique produces apparent anisotropies in the reconstructed halo distribution over all the scales which mimic RSD. On small scales, the apparent anisotropic clustering is caused by exclusion of haloes within the anisotropic cylinder used by the CGM. On large scales, the misidentification of different haloes in the large-scale structures, aligned along the line of sight, into the same CGM group causes the apparent anisotropic clustering via their cross-correlation with the CGM haloes. We construct an empirical model for the CGM halo power spectrum, which includes correction terms derived using the CGM window function at small scales as well as the linear matter power spectrum multiplied by a simple anisotropic function at large scales. We apply this model to a mock galaxy catalogue at z = 0.5, designed to resemble Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies, and find that our model can predict both the monopole and quadrupole power spectra of the host haloes up to k < 0.5 {{h Mpc^{-1}}} to within 5 per cent.

Observing Galaxy Mergers in Simulations

NASA Astrophysics Data System (ADS)

Snyder, Gregory

2018-01-01

I will describe results on mergers and morphology of distant galaxies. By mock-observing 3D cosmological simulations, we aim to contrast theory with data, design better diagnostics of physical processes, and examine unexpected signatures of galaxy formation. Recently, we conducted mock surveys of the Illustris Simulations to learn how mergers would appear in deep HST and JWST surveys. With this approach, we reconciled merger rates estimated using observed close galaxy pairs with intrinsic merger rates predicted by theory. This implies that the merger-pair observability time is probably shorter in the early universe, and therefore that major mergers are more common than implied by the simplest arguments. Further, we show that disturbance-based diagnostics of late-stage mergers can be improved significantly by combining multi-dimensional image information with simulated merger identifications to train automated classifiers. We then apply these classifiers to real measurements from the CANDELS fields, recovering a merger fraction increasing with redshift in broad agreement with pair fractions and simulations, and with statistical errors smaller by a factor of two than classical morphology estimators. This emphasizes the importance of using robust training sets, including cosmological simulations and multidimensional data, for interpreting observed processes in galaxy evolution.

Evolution of Galaxy Luminosity and Stellar-Mass Functions since $z=1$ with the Dark Energy Survey Science Verification Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capozzi, D.; et al.

We present the first study of the evolution of the galaxy luminosity and stellar-mass functions (GLF and GSMF) carried out by the Dark Energy Survey (DES). We describe the COMMODORE galaxy catalogue selected from Science Verification images. This catalogue is made ofmore » $$\\sim 4\\times 10^{6}$$ galaxies at $$0« less

"Observing" the Circumnuclear Stars and Gas in Disk Galaxy Simulations

NASA Astrophysics Data System (ADS)

Cook, Angela; Hicks, Erin K. S.

2018-06-01

We present simulations based on theoretical models of common disk processes designed to represent potential inflow observed within the central 500 pc of local Seyfert galaxies. Mock observations of these n-body plus smoothed particle hydrodynamical simulations provide the conceptual framework in which to identify the driving inflow mechanism, for example nuclear bars, and to quantify to the inflow based on observable properties. From these mock observations the azimuthal average of the flux distribution, velocity dispersion, and velocity of both the stars and interstellar medium on scales of 50pc have been measured at a range of inclinations angles. A comparison of the simulated disk galaxies with these observed azimuthal averages in 40 Seyfert galaxies measured as part of the KONA (Keck OSIRIS Nearby AGN) survey will be presented.

VizieR Online Data Catalog: A cosmic void catalog of SDSS DR12 BOSS galaxies (Mao+, 2017)

NASA Astrophysics Data System (ADS)

Mao, Q.; Berlind, A. A.; Scherrer, R. J.; Neyrinck, M. C.; Scoccimarro, R.; Tinker, J. L.; McBride, C. K.; Schneider, D. P.; Pan, K.; Bizyaev, D.; Malanushenko, E.; Malanushenko, V.

2017-08-01

We present a cosmic void catalog using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Release 12 and is the final catalog of SDSS-III. We take into account the survey boundaries, masks, and angular and radial selection functions, and apply the ZOBOV (Neyrinck 2008MNRAS.386.2101N) void finding algorithm to the Galaxy catalog. We identify a total of 10643 voids. After making quality cuts to ensure that the voids represent real underdense regions, we obtain 1228 voids with effective radii spanning the range 20-100h-1Mpc and with central densities that are, on average, 30% of the mean sample density. We release versions of the catalogs both with and without quality cuts. We discuss the basic statistics of voids, such as their size and redshift distributions, and measure the radial density profile of the voids via a stacking technique. In addition, we construct mock void catalogs from 1000 mock galaxy catalogs, and find that the properties of BOSS voids are in good agreement with those in the mock catalogs. We compare the stellar mass distribution of galaxies living inside and outside of the voids, and find no large difference. These BOSS and mock void catalogs are useful for a number of cosmological and galaxy environment studies. (1 data file).

Estimatining biases in the stellar dynamical black hole mass measurements in barred galaxies and prospects for measuring SMBH masses with JWST

NASA Astrophysics Data System (ADS)

Valluri, Monica; Vasiliev, Eugene; Bentz, Misty; Shen, Juntai

2018-04-01

Although 60% of disk galaxies are barred, stellar dynamical measurements of the masses of supermassive black holes (SMBH) in barred galaxies have always been obtained under the assumption that the bulges are axisymmetric. We use N-body simulations with self-consistently grown SMBHs in barred and unbarred galaxies to create a suite of mock Integral Field Spectrographic (IFS) datasets for galaxies with various observed orientations. We then apply an axisymmetric orbit superposition code to these mock IFS datasets to assess the reliability with which SMBH masses can be recovered. We also assess which disk and bar orientations give rise to biases. We use these simulations to assess whether or not existing SMBH measurements in barred galaxies are likely to be biased. We also present a brief preview of our JWST Early Release Science proposal to study the nuclear dynamics of nearby Seyfert I galaxy NGC 4151 with the NIRSpec Integral Field Spectrograph and describe how simulations of disk galaxies will used to create mock NIRSpec data to prepare for the real data.

The ASAS-SN bright supernova catalogue - III. 2016

NASA Astrophysics Data System (ADS)

Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Bose, S.; Beacom, J. F.; Bersier, D.; Chen, Ping; Chomiuk, L.; Falco, E.; Godoy-Rivera, D.; Morrell, N.; Pojmanski, G.; Shields, J. V.; Strader, J.; Stritzinger, M. D.; Thompson, Todd A.; Woźniak, P. R.; Bock, G.; Cacella, P.; Conseil, E.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Post, R. S.; Stone, G.; Wiethoff, W. S.

2017-11-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

The PyCASSO database: spatially resolved stellar population properties for CALIFA galaxies

NASA Astrophysics Data System (ADS)

de Amorim, A. L.; García-Benito, R.; Cid Fernandes, R.; Cortijo-Ferrero, C.; González Delgado, R. M.; Lacerda, E. A. D.; López Fernández, R.; Pérez, E.; Vale Asari, N.

2017-11-01

The Calar Alto Legacy Integral Field Area (CALIFA) survey, a pioneer in integral field spectroscopy legacy projects, has fostered many studies exploring the information encoded on the spatially resolved data on gaseous and stellar features in the optical range of galaxies. We describe a value-added catalogue of stellar population properties for CALIFA galaxies analysed with the spectral synthesis code starlight and processed with the pycasso platform. Our public database (http://pycasso.ufsc.br/, mirror at http://pycasso.iaa.es/) comprises 445 galaxies from the CALIFA Data Release 3 with COMBO data. The catalogue provides maps for the stellar mass surface density, mean stellar ages and metallicities, stellar dust attenuation, star formation rates, and kinematics. Example applications both for individual galaxies and for statistical studies are presented to illustrate the power of this data set. We revisit and update a few of our own results on mass density radial profiles and on the local mass-metallicity relation. We also show how to employ the catalogue for new investigations, and show a pseudo Schmidt-Kennicutt relation entirely made with information extracted from the stellar continuum. Combinations to other databases are also illustrated. Among other results, we find a very good agreement between star formation rate surface densities derived from the stellar continuum and the H α emission. This public catalogue joins the scientific community's effort towards transparency and reproducibility, and will be useful for researchers focusing on (or complementing their studies with) stellar properties of CALIFA galaxies.

Radio emission from dusty galaxies observed by AKARI

NASA Astrophysics Data System (ADS)

Pepiak, A.; Pollo, A.; Takeuchi, T. T.; Solarz, A.; Jurusik, W.

2014-10-01

We probe radio-infrared correlation for two samples of extragalactic sources from the local Universe from the AKARI All-Sky Catalogue. The first, smaller sample (1053 objects) was constructed by the cross-correlation of the AKARI/FIS All-Sky Survey Bright Source Catalogue, the AKARI IRC All-Sky Survey Point Source Catalogue and the NRAO VLA Sky Survey, i.e. it consists of sources detected in the mid- and far-infrared by AKARI, and at the 1.4 GHz radio frequency by NRAO. The second, larger sample (13,324 objects) was constructed by the cross-correlation of only the AKARI/FIS All-Sky Survey Bright Source Catalogue and the NRAO VLA Sky Survey, i.e. it consists of sources detected in the far-infrared and radio, without a condition to be detected in the mid-infrared. Additionally, all objects in both samples were identified as galaxies in the NED and/or SIMBAD databases, and a part of them is known to host active galactic nuclei (AGNs). For the present analysis, we have restricted our samples only to sources with known redshift z. In this paper, we analyse the far-infrared-radio correlation for both of these samples. We compare the ratio of infrared and radio emission from normal star-forming dusty galaxies and AGNs in both samples. For the smaller sample we obtained =2.14 for AGNs and =2.27 for normal galaxies, while for the larger sample =2.15 for AGNs and =2.22 for normal galaxies. An average value of the slope in both samples is ~2.2, which is consistent with the previous measurements from the literature.

X-ray selected stars in HRC and BHRC catalogues

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.; Paronyan, G. M.

2014-12-01

A joint HRC/BHRC Catalogue has been created based on merging of Hamburg ROSAT Catalogue (HRC) and Byurakan Hamburg ROSAT Catalogue (BHRC). Both have been made by optical identifications of X-ray sources based on low-dispersion spectra of the Hamburg Quasar Survey (HQS) using ROSAT Catalogues. As a result, the largest sample of 8132 (5341+2791) optically identified X-ray sources was created having count rate (CR) of photons ≤ 0.04 ct/s in the area with galactic latitudes |b|≤ 20° and declinations d≤ 0°.There are 4253 AGN, 492 galaxies, 1800 stars and 1587 unknown objects in the sample. All stars have been found in GSC 2.3.2, as well as most of them are in GALEX, USNO-B1.0, 2MASS and WISE catalogues. In addition, 1429 are in SDSS DR9 and 204 have SDSS spectra. For these stars we have carried out spectral classification and along with the bright stars, many new cataclysmic variables (CV), white dwarfs (WD) and late-type stars (K-M and C) have been revealed. For all stars, statistical studies of their multiwavelength properties have been made. An attempt to find a connection between the radiation fluxes in different bands for different types of sources, and identify their characteristics was made as well.

VizieR Online Data Catalog: PMA Catalogue (Akhmetov+, 2017)

NASA Astrophysics Data System (ADS)

Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

2017-06-01

The idea for creating the catalogue is very simple. The PMA catalogue has been derived from a combination of two catalogues, namely 2MASS and Gaia DR1. The difference of epochs of observations for these catalogues is approximately 15 yr. The positions of objects in the Gaia DR1 catalogue are referred to the reference frame, which is consistent with ICRF to better than 0.1 mas for the J2015.0 epoch. The positions of objects in 2MASS are referred to HCRF, which, as was shown in Kovalevsky et al. (1997A&A...323..620K), is aligned with the ICRF to within ±0.6 mas at the epoch 1991.25 and is non-rotating with respect to distant extragalactic objects to within ±0.25mas/yr. By comparing the positions of the common objects contained in the catalogues, it is possible to determine their proper motions within their common range of stellar magnitudes by dividing differences of positions over the time interval between their observations. Formally, proper motions derived in such a way are given in the ICRF system, because the positions of both Gaia DR1 stars and those of 2MASS objects (through Hipparcos/Tycho-2 stars) are given in the ICRF and cover the whole sphere without gaps. We designate them further in this paper as relative, with the aim of discriminating them from absolute ones, which refer to the reference frame defined by the positions of about 1.6 million galaxies from Gaia DR1. There is no possibility of obtaining estimates of individual errors of proper motions of stars for the PMA Catalogue from the intrinsic convergence, because the direct errors for positions are not indicated in 2MASS. Therefore we use some indirect methods to obtain the estimates of uncertainties for proper motions. After elimination of the systematic errors, the root-mean-squared deviation of the coordinate differences of extended sources is about 200mas, and the mean number of galaxies inside each pixel is about 1300, so we expect the error of the absolute calibration to be 0.35mas

Cosmology with void-galaxy correlations.

PubMed

Hamaus, Nico; Wandelt, Benjamin D; Sutter, P M; Lavaux, Guilhem; Warren, Michael S

2014-01-31

Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute clustering amplitude of high-density regions mapped out by galaxy surveys, we propose a relative measurement that compares those to the underdense regions, cosmic voids. On the basis of realistic mock catalogs we demonstrate that cross correlating galaxies and voids opens up the possibility to calibrate galaxy bias and to define a static ruler thanks to the observable geometric nature of voids. We illustrate how the clustering of voids is related to mass compensation and show that volume-exclusion significantly reduces the degree of stochasticity in their spatial distribution. Extracting the spherically averaged distribution of galaxies inside voids from their cross correlations reveals a remarkable concordance with the mass-density profile of voids.

A Bayesian Hierarchical Approach to Galaxy-Galaxy Lensing

NASA Astrophysics Data System (ADS)

Sonnenfeld, Alessandro; Leauthaud, Alexie

2018-04-01

We present a Bayesian hierarchical inference formalism to study the relation between the properties of dark matter halos and those of their central galaxies using weak gravitational lensing. Unlike traditional methods, this technique does not resort to stacking the weak lensing signal in bins, and thus allows for a more efficient use of the information content in the data. Our method is particularly useful for constraining scaling relations between two or more galaxy properties and dark matter halo mass, and can also be used to constrain the intrinsic scatter in these scaling relations. We show that, if observational scatter is not properly accounted for, the traditional stacking method can produce biased results when exploring correlations between multiple galaxy properties and halo mass. For example, this bias can affect studies of the joint correlation between galaxy mass, halo mass, and galaxy size, or galaxy colour. In contrast, our method easily and efficiently handles the intrinsic and observational scatter in multiple galaxy properties and halo mass. We test our method on mocks with varying degrees of complexity. We find that we can recover the mean halo mass and concentration, each with a 0.1 dex accuracy, and the intrinsic scatter in halo mass with a 0.05 dex accuracy. In its current version, our method will be most useful for studying the weak lensing signal around central galaxies in groups and clusters, as well as massive galaxies samples with log M* > 11, which have low satellite fractions.

A Bayesian hierarchical approach to galaxy-galaxy lensing

NASA Astrophysics Data System (ADS)

Sonnenfeld, Alessandro; Leauthaud, Alexie

2018-07-01

We present a Bayesian hierarchical inference formalism to study the relation between the properties of dark matter haloes and those of their central galaxies using weak gravitational lensing. Unlike traditional methods, this technique does not resort to stacking the weak lensing signal in bins, and thus allows for a more efficient use of the information content in the data. Our method is particularly useful for constraining scaling relations between two or more galaxy properties and dark matter halo mass, and can also be used to constrain the intrinsic scatter in these scaling relations. We show that, if observational scatter is not properly accounted for, the traditional stacking method can produce biased results when exploring correlations between multiple galaxy properties and halo mass. For example, this bias can affect studies of the joint correlation between galaxy mass, halo mass, and galaxy size, or galaxy colour. In contrast, our method easily and efficiently handles the intrinsic and observational scatter in multiple galaxy properties and halo mass. We test our method on mocks with varying degrees of complexity. We find that we can recover the mean halo mass and concentration, each with a 0.1 dex accuracy, and the intrinsic scatter in halo mass with a 0.05 dex accuracy. In its current version, our method will be most useful for studying the weak lensing signal around central galaxies in groups and clusters, as well as massive galaxies samples with log M* > 11, which have low satellite fractions.

Optical Identifications of High-Redshift Galaxy Clusters from the Planck Sunyaev-Zeldovich Survey

NASA Astrophysics Data System (ADS)

Burenin, R. A.; Bikmaev, I. F.; Khamitov, I. M.; Zaznobin, I. A.; Khorunzhev, G. A.; Eselevich, M. V.; Afanasiev, V. L.; Dodonov, S. N.; Rubiño-Martín, J.-A.; Aghanim, N.; Sunyaev, R. A.

2018-05-01

We present the results of optical identifications and spectroscopic redshift measurements for galaxy clusters from the second Planck catalogue of Sunyaev-Zeldovich sources (PSZ2) located at high redshifts, z ≈ 0.7-0.9. We used the data of optical observations with the Russian-Turkish 1.5-mtelescope (RTT-150), the Sayan Observatory 1.6-m telescope, the Calar Alto 3.5-m telescope, and the 6-m SAO RAS telescope (BTA). The spectroscopic redshift measurements were obtained for seven galaxy clusters, including one cluster, PSZ2 G126.57+51.61, from the cosmological sample of the PSZ2 catalogue. In the central regions of two clusters, PSZ2 G069.39+68.05 and PSZ2 G087.39-34.58, we detected arcs of strong gravitational lensing of background galaxies, one of which is at redshift z = 4.262. The data presented below roughly double the number of known galaxy clusters in the second Planck catalogue of Sunyaev-Zeldovich sources at high redshifts, z ≈ 0.8.

Radio emission in peculiar galaxies

NASA Technical Reports Server (NTRS)

Demellorabaca, Dulia F.; Abraham, Zulema

1990-01-01

During the last decades a number of surveys of peculiar galaxies have been carried out and accurate positions become available. Since peculiarities are a possible evidence of radio emission (Wright, 1974; Sulentic, 1976; Stocke et al., 1978), the authors selected a sample of 24 peculiar galaxies with optical jet-like features or extensions in different optical catalogues, mainly the Catalogue of Southern Peculiar Galaxies and Associations (Arp and Madore, 1987) and the ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts, 1982) for observation at the radio continuum frequency of 22 GHz. The sample is listed in a table. Sol (1987) studied this sample and concluded that the majority of the jet-like features seem to admit an explanation in terms of interactive galaxies with bridges and/or tails due to tidal effects. Only in a few cases do the jets seem to be possibly linked to some nuclear activity of the host galaxy. The observations were made with the 13.7m-radome enclosed Itapetinga Radiotelescope (HPBW of 4.3 arcmin), in Brazil. The receiver was a 1 GHz d.s.b. super-heterodine mixer operated in total-power mode, with a system temperature of approximately 800 K. The observational technique consisted in scans in right ascention, centralized in the optical position of the galaxy. The amplitude of one scan was 43 arcmin, and its duration time was 20 seconds. The integration time was at least 2 hours (12 ten-minute observations) and the sensibility limit adopted was an antenna temperature greater than 3 times the r.m.s. error of the baseline determination. Virgo A was used as the calibrator source. Three galaxies were detected for the first time as radio sources and four other known galaxies at low frequencies had their flux densities measured at 22 GHz. The results for these sources are presented.

Full-sky Ray-tracing Simulation of Weak Lensing Using ELUCID Simulations: Exploring Galaxy Intrinsic Alignment and Cosmic Shear Correlations

NASA Astrophysics Data System (ADS)

Wei, Chengliang; Li, Guoliang; Kang, Xi; Luo, Yu; Xia, Qianli; Wang, Peng; Yang, Xiaohu; Wang, Huiyuan; Jing, Yipeng; Mo, Houjun; Lin, Weipeng; Wang, Yang; Li, Shijie; Lu, Yi; Zhang, Youcai; Lim, S. H.; Tweed, Dylan; Cui, Weiguang

2018-01-01

The intrinsic alignment of galaxies is an important systematic effect in weak-lensing surveys, which can affect the derived cosmological parameters. One direct way to distinguish different alignment models and quantify their effects on the measurement is to produce mock weak-lensing surveys. In this work, we use the full-sky ray-tracing technique to produce mock images of galaxies from the ELUCID N-body simulation run with WMAP9 cosmology. In our model, we assume that the shape of the central elliptical galaxy follows that of the dark matter halo, and that of the spiral galaxy follows the halo spin. Using the mock galaxy images, a combination of galaxy intrinsic shape and the gravitational shear, we compare the predicted tomographic shear correlations to the results of the Kilo-Degree Survey (KiDS) and Deep Lens Survey (DLS). We find that our predictions stay between the KiDS and DLS results. We rule out a model in which the satellite galaxies are radially aligned with the center galaxy; otherwise, the shear correlations on small scales are too high. Most importantly, we find that although the intrinsic alignment of spiral galaxies is very weak, they induce a positive correlation between the gravitational shear signal and the intrinsic galaxy orientation (GI). This is because the spiral galaxy is tangentially aligned with the nearby large-scale overdensity, contrary to the radial alignment of the elliptical galaxy. Our results explain the origin of the detected positive GI term in the weak-lensing surveys. We conclude that in future analyses, the GI model must include the dependence on galaxy types in more detail.

Probing the Cosmological Principle in the counts of radio galaxies at different frequencies

NASA Astrophysics Data System (ADS)

Bengaly, Carlos A. P.; Maartens, Roy; Santos, Mario G.

2018-04-01

According to the Cosmological Principle, the matter distribution on very large scales should have a kinematic dipole that is aligned with that of the CMB. We determine the dipole anisotropy in the number counts of two all-sky surveys of radio galaxies. For the first time, this analysis is presented for the TGSS survey, allowing us to check consistency of the radio dipole at low and high frequencies by comparing the results with the well-known NVSS survey. We match the flux thresholds of the catalogues, with flux limits chosen to minimise systematics, and adopt a strict masking scheme. We find dipole directions that are in good agreement with each other and with the CMB dipole. In order to compare the amplitude of the dipoles with theoretical predictions, we produce sets of lognormal realisations. Our realisations include the theoretical kinematic dipole, galaxy clustering, Poisson noise, simulated redshift distributions which fit the NVSS and TGSS source counts, and errors in flux calibration. The measured dipole for NVSS is ~2 times larger than predicted by the mock data. For TGSS, the dipole is almost ~ 5 times larger than predicted, even after checking for completeness and taking account of errors in source fluxes and in flux calibration. Further work is required to understand the nature of the systematics that are the likely cause of the anomalously large TGSS dipole amplitude.

Percolation galaxy groups and clusters in the sdss redshift survey: identification, catalogs, and the multiplicity function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berlind, Andreas A.; Frieman, Joshua A.; Weinberg, David H.

2006-01-01

We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths to recover galaxy systems that occupy the same dark matter halos, using a set of mock catalogs created by populating halos of N-body simulations with galaxies. Extensive tests with these mock catalogs show that no combination of perpendicular and line-of-sight linking lengths is able to yield groups and clusters that simultaneously recover the true halo multiplicity function, projected size distribution, and velocity dispersion. We adopt a linking length combination that yields, for galaxy groups withmore » ten or more members: a group multiplicity function that is unbiased with respect to the true halo multiplicity function; an unbiased median relation between the multiplicities of groups and their associated halos; a spurious group fraction of less than {approx}1%; a halo completeness of more than {approx}97%; the correct projected size distribution as a function of multiplicity; and a velocity dispersion distribution that is {approx}20% too low at all multiplicities. These results hold over a range of mock catalogs that use different input recipes of populating halos with galaxies. We apply our group-finding algorithm to the SDSS data and obtain three group and cluster catalogs for three volume-limited samples that cover 3495.1 square degrees on the sky. We correct for incompleteness caused by fiber collisions and survey edges, and obtain measurements of the group multiplicity function, with errors calculated from realistic mock catalogs. These multiplicity function measurements provide a key constraint on the relation between galaxy populations and dark matter halos.« less

General properties of a sample of isolated galaxies containing active nucleus

NASA Astrophysics Data System (ADS)

Chesnok, N. G.

2010-10-01

We investigated the general properties of 62 isolated galaxies with active nuclei (AGN) selected from the Catalogue 2MIG and Catalogue Veron+2010. The main characteristics of the distribution of these objects are given. The sample under investigation can be included to the scientific research program for "Radioastron".

Stellar-to-halo mass relation of cluster galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemiec, Anna; Jullo, Eric; Limousin, Marceau

In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can bemore » used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science veri cation archive, the CFHTLenS and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we nd a stellar to halo mass relation in good agreement with the theoretical expectations from Moster, Naab & White (2013) for central galaxies. In the centre of the cluster, we nd that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this nding as further evidence for tidal stripping of dark matter haloes in high density environments.« less

Stellar-to-halo mass relation of cluster galaxies

DOE PAGES

Niemiec, Anna; Jullo, Eric; Limousin, Marceau; ...

2017-07-04

In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can bemore » used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science veri cation archive, the CFHTLenS and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we nd a stellar to halo mass relation in good agreement with the theoretical expectations from Moster, Naab & White (2013) for central galaxies. In the centre of the cluster, we nd that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this nding as further evidence for tidal stripping of dark matter haloes in high density environments.« less

Friends-of-friends galaxy group finder with membership refinement. Application to the local Universe

NASA Astrophysics Data System (ADS)

Tempel, E.; Kipper, R.; Tamm, A.; Gramann, M.; Einasto, M.; Sepp, T.; Tuvikene, T.

2016-04-01

Context. Groups form the most abundant class of galaxy systems. They act as the principal drivers of galaxy evolution and can be used as tracers of the large-scale structure and the underlying cosmology. However, the detection of galaxy groups from galaxy redshift survey data is hampered by several observational limitations. Aims: We improve the widely used friends-of-friends (FoF) group finding algorithm with membership refinement procedures and apply the method to a combined dataset of galaxies in the local Universe. A major aim of the refinement is to detect subgroups within the FoF groups, enabling a more reliable suppression of the fingers-of-God effect. Methods: The FoF algorithm is often suspected of leaving subsystems of groups and clusters undetected. We used a galaxy sample built of the 2MRS, CF2, and 2M++ survey data comprising nearly 80 000 galaxies within the local volume of 430 Mpc radius to detect FoF groups. We conducted a multimodality check on the detected groups in search for subgroups. We furthermore refined group membership using the group virial radius and escape velocity to expose unbound galaxies. We used the virial theorem to estimate group masses. Results: The analysis results in a catalogue of 6282 galaxy groups in the 2MRS sample with two or more members, together with their mass estimates. About half of the initial FoF groups with ten or more members were split into smaller systems with the multimodality check. An interesting comparison to our detected groups is provided by another group catalogue that is based on similar data but a completely different methodology. Two thirds of the groups are identical or very similar. Differences mostly concern the smallest and largest of these other groups, the former sometimes missing and the latter being divided into subsystems in our catalogue. The catalogues are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http

The role of host galaxy for the environmental dependence of active nuclei in local galaxies

NASA Astrophysics Data System (ADS)

Davies, Richard I.; Hicks, E. K. S.; Erwin, P.; Burtscher, L.; Contursi, A.; Genzel, R.; Janssen, A.; Koss, M.; Lin, M.-Y.; Lutz, D.; Maciejewski, W.; Müller-Sánchez, F.; Orban de Xivry, G.; Ricci, C.; Riffel, R.; Riffel, R. A.; Rosario, D.; Schartmann, M.; Schnorr-Müller, A.; Shimizu, T.; Sternberg, A.; Sturm, E.; Storchi-Bergmann, T.; Tacconi, L.; Veilleux, S.

2017-04-01

We discuss the environment of local hard X-ray selected active galaxies, with reference to two independent group catalogues. We find that the fraction of these AGN in S0 host galaxies decreases strongly as a function of galaxy group size (halo mass) - which contrasts with the increasing fraction of galaxies of S0 type in denser environments. However, there is no evidence for an environmental dependence of AGN in spiral galaxies. Because most AGN are found in spiral galaxies, this dilutes the signature of environmental dependence for the population as a whole. We argue that the differing results for AGN in disc-dominated and bulge-dominated galaxies are related to the source of the gas fuelling the AGN, and so may also impact the luminosity function, duty cycle and obscuration. We find that there is a significant difference in the luminosity function for AGN in spiral and S0 galaxies, and tentative evidence for some difference in the fraction of obscured AGN.

The ASAS-SN bright supernova catalogue – III. 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

In this catalogue we summarize information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m peak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al.more » This is then the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

The ASAS-SN bright supernova catalogue – III. 2016

DOE PAGES

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.; ...

2017-08-18

In this catalogue we summarize information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m peak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al.more » This is then the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

VizieR Online Data Catalog: Reference Catalogue of Bright Galaxies (RC1; de Vaucouleurs+ 1964)

NASA Astrophysics Data System (ADS)

de Vaucouleurs, G.; de Vaucouleurs, A.

1995-11-01

The Reference Catalogue of Bright Galaxies lists for each entry the following information: NGC number, IC number, or A number; A, B, or C designation; B1950.0 positions, position at 100 year precession; galactic and supergalactic positions; revised morphological type and source; type and color class in Yerkes list 1 and 2; Hubble-Sandage type; revised Hubble type according to Holmberg; logarithm of mean major diameter (log D) and ratio of major to minor diameter (log R) and their weights; logarithm of major diameter; sources of the diameters; David Dunlap Observatory type and luminosity class; Harvard photographic apparent magnitude; weight of V, B-V(0), U-B(0); integrated magnitude B(0) and its weight in the B system; mean surface brightness in magnitude per square minute of arc and sources for the B magnitude; mean B surface brightness derived from corrected Harvard magnitude; the integrated color index in the standard B-V system; "intrinsic" color index; sources of B-V and/or U-B; integrated color in the standard U-B system; observed radial velocity in km/sec; radial velocity corrected for solar motion in km/sec; sources of radial velocities; solar motion correction; and direct photographic source. The catalog was created by concatenating four files side by side. (1 data file).

Properties of an H I-selected galaxy sample

NASA Technical Reports Server (NTRS)

Szomoru, Arpad; Guhathakurta, Puragra; Van Gorkom, Jacqueline H.; Knapen, Johan H.; Weinberg, David H.; Fruchter, Andrew S.

1994-01-01

We analyze the properties of a sample of galaxies identified in a 21cm, H I-line survey of selected areas in the Perseus-Pisces supercluster and its foreground void. Twelve fields were observed in the supercluster, five of them (target fields) centered on optically bright galaxies, and the other seven (blank fields) selected to contain no bright galaxies within 45 min. of their centers. We detected nine previously uncatalogued, gas-rich galaxies, six of them in the target fields. We also detected H I from seven previously catalogued galaxies in these fields. Observations in the void covered the same volume as the 12 supercluster fields at the same H I-mass sensitivity, but no objects were detected. Combining out H I data with optical broadband and H alpha imaging, we conclude that the properties of H I-selected galaxies do not differ substantially from those of late-type galaxies found in optical surveys. In particular, the galaxies in our sample do not appear to be unusually faint for their H I mass, or for their circular velocity. We find tentative evidence for a connection between optical surface brightness and degree of isolation, in the sense that low surface brightness galaxies tend to be more isolated. The previously catalogued, optically bright galaxies in our survey volume dominate the total H I mass density and cross section; the uncatalogued galaxies contribute only approximately 19 percent of the mass and approximately 12 percent of the cross section. Thus, existing estimates of the density and cross section of neutral hydrogen, most of which are based on optically selected galaxy samples, are probably accurate. Such estimates can be used to compare the nearby universe to the high-redshift universe probed by quasar absorption lines.

The influence of galaxy environment on the stellar initial mass function of early-type galaxies

NASA Astrophysics Data System (ADS)

Rosani, Giulio; Pasquali, Anna; La Barbera, Francesco; Ferreras, Ignacio; Vazdekis, Alexandre

2018-06-01

In this paper, we investigate whether the stellar initial mass function (IMF) of early-type galaxies depends on their host environment. To this purpose, we have selected a sample of early-type galaxies from the SPIDER catalogue, characterized their environment through the group catalogue of Wang et al., and used their optical Sloan Digital Sky Survey (SDSS) spectra to constrain the IMF slope, through the analysis of IMF-sensitive spectral indices. To reach a high enough signal-to-noise ratio, we have stacked spectra in velocity dispersion (σ0) bins, on top of separating the sample by galaxy hierarchy and host halo mass, as proxies for galaxy environment. In order to constrain the IMF, we have compared observed line strengths and predictions of MIUSCAT/EMILES synthetic stellar population models, with varying age, metallicity, and `bimodal' (low-mass tapered) IMF slope (Γ _b). Consistent with previous studies, we find that Γ _b increases with σ0, becoming bottom-heavy (i.e. an excess of low-mass stars with respect to the Milky Way like IMF) at high σ0. We find that this result is robust against the set of isochrones used in the stellar population models, as well as the way the effect of elemental abundance ratios is taken into account. We thus conclude that it is possible to use currently state-of-the-art stellar population models and intermediate resolution spectra to consistently probe IMF variations. For the first time, we show that there is no dependence of Γb on environment or galaxy hierarchy, as measured within the 3 arcsec SDSS fibre, thus leaving the IMF as an intrinsic galaxy property, possibly set already at high redshift.

Late-stage galaxy mergers in cosmos to z ∼ 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lackner, C. N.; Silverman, J. D.; Salvato, M.

2014-12-01

The role of major mergers in galaxy and black hole formation is not well-constrained. To help address this, we develop an automated method to identify late-stage galaxy mergers before coalescence of the galactic cores. The resulting sample of mergers is distinct from those obtained using pair-finding and morphological indicators. Our method relies on median-filtering of high-resolution images to distinguish two concentrated galaxy nuclei at small separations. This method does not rely on low surface brightness features to identify mergers, and is therefore reliable to high redshift. Using mock images, we derive statistical contamination and incompleteness corrections for the fraction ofmore » late-stage mergers. The mock images show that our method returns an uncontaminated (<10%) sample of mergers with projected separations between 2.2 and 8 kpc out to z∼1. We apply our new method to a magnitude-limited (m{sub FW} {sub 814}<23) sample of 44,164 galaxies from the COSMOS HST/ACS catalog. Using a mass-complete sample with logM{sub ∗}/M{sub ⊙}>10.6 and 0.25« less

Integrated HI emission in galaxy groups and clusters

NASA Astrophysics Data System (ADS)

Ai, Mei; Zhu, Ming; Fu, Jian

2017-09-01

The integrated HI emission from hierarchical structures such as groups and clusters of galaxies can be detected by FAST at intermediate redshifts. Here we propose to use FAST to study the evolution of the global HI content of clusters and groups over cosmic time by measuring their integrated HI emissions. We use the Virgo Cluster as an example to estimate the detection limit of FAST, and have estimated the integration time to detect a Virgo type cluster at different redshifts (from z = 0.1 to z = 1.5).We have also employed a semi-analytic model (SAM) to simulate the evolution of HI contents in galaxy clusters. Our simulations suggest that the HI mass of a Virgo-like cluster could be 2-3 times higher and the physical size could be more than 50% smaller when redshift increases from z = 0.3 to z = 1. Thus the integration time could be reduced significantly and gas rich clusters at intermediate redshifts can be detected by FAST in less than 2 hours of integration time. For the local Universe, we have also used SAM simulations to create mock catalogs of clusters to predict the outcomes from FAST all sky surveys. Comparing with the optically selected catalogs derived by cross matching the galaxy catalogs from the SDSS survey and the ALFALFA survey, we find that the HI mass distribution of the mock catalog with 20 s of integration time agrees well with that of observations. However, the mock catalog with 120 s of integration time predicts many more groups and clusters that contain a population of low mass HI galaxies not detected by the ALFALFA survey. A future deep HI blind sky survey with FAST would be able to test such prediction and set constraints on the numerical simulation models. The observational strategy and sample selections for future FAST observations of galaxy clusters at high redshifts are also discussed.

X-ray morphological study of galaxy cluster catalogues

NASA Astrophysics Data System (ADS)

Democles, Jessica; Pierre, Marguerite; Arnaud, Monique

2016-07-01

Context : The intra-cluster medium distribution as probed by X-ray morphology based analysis gives good indication of the system dynamical state. In the race for the determination of precise scaling relations and understanding their scatter, the dynamical state offers valuable information. Method : We develop the analysis of the centroid-shift so that it can be applied to characterize galaxy cluster surveys such as the XXL survey or high redshift cluster samples. We use it together with the surface brightness concentration parameter and the offset between X-ray peak and brightest cluster galaxy in the context of the XXL bright cluster sample (Pacaud et al 2015) and a set of high redshift massive clusters detected by Planck and SPT and observed by both XMM-Newton and Chandra observatories. Results : Using the wide redshift coverage of the XXL sample, we see no trend between the dynamical state of the systems with the redshift.

Log-Normal Distribution of Cosmic Voids in Simulations and Mocks

NASA Astrophysics Data System (ADS)

Russell, E.; Pycke, J.-R.

2017-01-01

Following up on previous studies, we complete here a full analysis of the void size distributions of the Cosmic Void Catalog based on three different simulation and mock catalogs: dark matter (DM), haloes, and galaxies. Based on this analysis, we attempt to answer two questions: Is a three-parameter log-normal distribution a good candidate to satisfy the void size distributions obtained from different types of environments? Is there a direct relation between the shape parameters of the void size distribution and the environmental effects? In an attempt to answer these questions, we find here that all void size distributions of these data samples satisfy the three-parameter log-normal distribution whether the environment is dominated by DM, haloes, or galaxies. In addition, the shape parameters of the three-parameter log-normal void size distribution seem highly affected by environment, particularly existing substructures. Therefore, we show two quantitative relations given by linear equations between the skewness and the maximum tree depth, and between the variance of the void size distribution and the maximum tree depth, directly from the simulated data. In addition to this, we find that the percentage of voids with nonzero central density in the data sets has a critical importance. If the number of voids with nonzero central density reaches ≥3.84% in a simulation/mock sample, then a second population is observed in the void size distributions. This second population emerges as a second peak in the log-normal void size distribution at larger radius.

LOG-NORMAL DISTRIBUTION OF COSMIC VOIDS IN SIMULATIONS AND MOCKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, E.; Pycke, J.-R., E-mail: er111@nyu.edu, E-mail: jrp15@nyu.edu

2017-01-20

Following up on previous studies, we complete here a full analysis of the void size distributions of the Cosmic Void Catalog based on three different simulation and mock catalogs: dark matter (DM), haloes, and galaxies. Based on this analysis, we attempt to answer two questions: Is a three-parameter log-normal distribution a good candidate to satisfy the void size distributions obtained from different types of environments? Is there a direct relation between the shape parameters of the void size distribution and the environmental effects? In an attempt to answer these questions, we find here that all void size distributions of thesemore » data samples satisfy the three-parameter log-normal distribution whether the environment is dominated by DM, haloes, or galaxies. In addition, the shape parameters of the three-parameter log-normal void size distribution seem highly affected by environment, particularly existing substructures. Therefore, we show two quantitative relations given by linear equations between the skewness and the maximum tree depth, and between the variance of the void size distribution and the maximum tree depth, directly from the simulated data. In addition to this, we find that the percentage of voids with nonzero central density in the data sets has a critical importance. If the number of voids with nonzero central density reaches ≥3.84% in a simulation/mock sample, then a second population is observed in the void size distributions. This second population emerges as a second peak in the log-normal void size distribution at larger radius.« less

Identification of stars in a J1744.0 star catalogue Yixiangkaocheng

NASA Astrophysics Data System (ADS)

Ahn, S.-H.

2012-05-01

The stars in the Chinese star catalogue, Yixiangkaocheng, which were edited by the Jesuit astronomer Kögler in AD 1744 and published in AD 1756, are identified with their counterparts in the Hipparcos catalogue. The equinox of the catalogue is confirmed to be J1744.0. By considering the precession of equinox, proper motions and nutation, the star closest to the location of each star in Yixiangkaocheng, having a proper magnitude, is selected as the corresponding identified star. I identified 2848 stars and 13 nebulosities out of 3083 objects in Yixiangkaocheng, and so the identification rate reached 92.80 per cent. I find that the magnitude classification system in Yixiangkaocheng agrees with the modern magnitude system. The catalogue includes dim stars, whose visual magnitudes are larger than 7, but most of these stars have Flamsteed designations. I find that the stars whose declination is lower than -30° have relatively larger offsets and different systematic behaviour from other stars. This indicates that there might be two different sources of stars in Yixiangkaocheng. In particular, I find that μ1 Sco and γ1 Sgr approximately mark the boundary between two different source catalogues. The observer's location, as estimated from these facts, agrees with the latitude of Greenwich where Flamsteed made his observations. The positional offsets between the Yixiangkaocheng stars and the Hipparcos stars are 0.6 arcmin, which implies that the source catalogue of stars with δ > -30° must have come from telescopic observations. Nebulosities in Yixiangkaocheng are identified with a few double stars, o Cet (the variable star, Mira), the Andromeda galaxy, ω Cen and NGC6231. These entities are associated with listings in Halley's Catalogue of the Southern Stars of AD 1679 as well as Flamsteed's catalogue of AD 1690.

A new catalogue of Galactic novae: investigation of the MMRD relation and spatial distribution

NASA Astrophysics Data System (ADS)

Özdönmez, Aykut; Ege, Ergün; Güver, Tolga; Ak, Tansel

2018-05-01

In this study, a new Galactic novae catalogue is introduced collecting important parameters of these sources such as their light-curve parameters, classifications, full width half-maximum (FWHM) of Hα line, distances and interstellar reddening estimates. The catalogue is also published on a website with a search option via a SQL query and an online tool to re-calculate the distance/reddening of a nova from the derived reddening-distance relations. Using the novae in the catalogue, the existence of a maximum magnitude-rate of decline (MMRD) relation in the Galaxy is investigated. Although an MMRD relation was obtained, a significant scattering in the resulting MMRD distribution still exists. We suggest that the MMRD relation likely depends on other parameters in addition to the decline time, as FWHM Hα, the light-curve shapes. Using two different samples depending on the distances in the catalogue and from the derived MMRD relation, the spatial distributions of Galactic novae as a function of their spectral and speed classes were studied. The investigation on the Galactic model parameters implies that best estimates for the local outburst density are 3.6 and 4.2 × 10-10 pc-3 yr-1 with a scale height of 148 and 175 pc, while the space density changes in the range of 0.4-16 × 10-6 pc-3. The local outburst density and scale height obtained in this study infer that the disc nova rate in the Galaxy is in the range of ˜20 to ˜100 yr-1 with an average estimate 67^{+21}_{-17} yr-1.

High–frequency cluster radio galaxies: Luminosity functions and implications for SZE–selected cluster samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Nikhel; Saro, A.; Mohr, J. J.

We study the overdensity of point sources in the direction of X-ray-selected galaxy clusters from the meta-catalogue of X-ray-detected clusters of galaxies (MCXC; < z > = 0.14) at South Pole Telescope (SPT) and Sydney University Molonglo Sky Survey (SUMSS) frequencies. Flux densities at 95, 150 and 220 GHz are extracted from the 2500 deg 2 SPT-SZ survey maps at the locations of SUMSS sources, producing a multifrequency catalogue of radio galaxies. In the direction of massive galaxy clusters, the radio galaxy flux densities at 95 and 150 GHz are biased low by the cluster Sunyaev–Zel’dovich Effect (SZE) signal, whichmore » is negative at these frequencies. We employ a cluster SZE model to remove the expected flux bias and then study these corrected source catalogues. We find that the high-frequency radio galaxies are centrally concentrated within the clusters and that their luminosity functions (LFs) exhibit amplitudes that are characteristically an order of magnitude lower than the cluster LF at 843 MHz. We use the 150 GHz LF to estimate the impact of cluster radio galaxies on an SPT-SZ like survey. The radio galaxy flux typically produces a small bias on the SZE signal and has negligible impact on the observed scatter in the SZE mass–observable relation. If we assume there is no redshift evolution in the radio galaxy LF then 1.8 ± 0.7 per cent of the clusters with detection significance ξ ≥ 4.5 would be lost from the sample. As a result, allowing for redshift evolution of the form (1 + z) 2.5 increases the incompleteness to 5.6 ± 1.0 per cent. Improved constraints on the evolution of the cluster radio galaxy LF require a larger cluster sample extending to higher redshift.« less

High–frequency cluster radio galaxies: Luminosity functions and implications for SZE–selected cluster samples

DOE PAGES

Gupta, Nikhel; Saro, A.; Mohr, J. J.; ...

2017-01-15

We study the overdensity of point sources in the direction of X-ray-selected galaxy clusters from the meta-catalogue of X-ray-detected clusters of galaxies (MCXC; < z > = 0.14) at South Pole Telescope (SPT) and Sydney University Molonglo Sky Survey (SUMSS) frequencies. Flux densities at 95, 150 and 220 GHz are extracted from the 2500 deg 2 SPT-SZ survey maps at the locations of SUMSS sources, producing a multifrequency catalogue of radio galaxies. In the direction of massive galaxy clusters, the radio galaxy flux densities at 95 and 150 GHz are biased low by the cluster Sunyaev–Zel’dovich Effect (SZE) signal, whichmore » is negative at these frequencies. We employ a cluster SZE model to remove the expected flux bias and then study these corrected source catalogues. We find that the high-frequency radio galaxies are centrally concentrated within the clusters and that their luminosity functions (LFs) exhibit amplitudes that are characteristically an order of magnitude lower than the cluster LF at 843 MHz. We use the 150 GHz LF to estimate the impact of cluster radio galaxies on an SPT-SZ like survey. The radio galaxy flux typically produces a small bias on the SZE signal and has negligible impact on the observed scatter in the SZE mass–observable relation. If we assume there is no redshift evolution in the radio galaxy LF then 1.8 ± 0.7 per cent of the clusters with detection significance ξ ≥ 4.5 would be lost from the sample. As a result, allowing for redshift evolution of the form (1 + z) 2.5 increases the incompleteness to 5.6 ± 1.0 per cent. Improved constraints on the evolution of the cluster radio galaxy LF require a larger cluster sample extending to higher redshift.« less

The nature of assembly bias - III. Observational properties

NASA Astrophysics Data System (ADS)

Lacerna, Ivan; Padilla, Nelson; Stasyszyn, Federico

2014-10-01

We analyse galaxies in groups in the Sloan Digital Sky Survey (SDSS) and find a weak but significant assembly-type bias, where old central galaxies have a higher clustering amplitude (61 ± 9 per cent) at scales >1 h-1 Mpc than young central galaxies of equal host halo mass (Mh ˜ 1011.8 h- 1 M⊙). The observational sample is volume limited out to z = 0.1 with Mr - 5 log (h) ≤ -19.6. We construct a mock catalogue of galaxies that shows a similar signal of assembly bias (46 ± 9 per cent) at the same halo mass. We then adapt the model presented by Lacerna & Padilla (Paper I) to redefine the overdensity peak height, which traces the assembly bias such that galaxies in equal density peaks show the same clustering regardless of their stellar age, but this time using observational features such as a flux limit. The proxy for peak height, which is proposed as a better alternative than the virial mass, consists in the total mass given by the mass of neighbour host haloes in cylinders centred at each central galaxy. The radius of the cylinder is parameterized as a function of stellar age and virial mass. The best-fitting sets of parameters that make the assembly bias signal lower than 5-15 per cent for both SDSS and mock central galaxies are similar. The idea behind the parameterization is not to minimize the bias, but it is to use this method to understand the physical features that produce the assembly bias effect. Even though the tracers of the density field used here differ significantly from those used in Paper I, our analysis of the simulated catalogue indicates that the different tracers produce correlated proxies, and therefore the reason behind assembly bias is the crowding of peaks in both simulations and the SDSS.

Early-type galaxies in the Antlia cluster: catalogue and isophotal analysis

NASA Astrophysics Data System (ADS)

Calderón, Juan P.; Bassino, Lilia P.; Cellone, Sergio A.; Gómez, Matías

2018-06-01

We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ˜ 35 Mpc. The observational material consists of CCD images of four 36 × 36 arcmin2 fields obtained with the MOSAIC II camera at the Blanco 4-m telescope at Cerro Tololo Interamerican Observatory. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is MB ˜ -9.6 mag, and the surface photometry parameters of each galaxy are derived from Sérsic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semimajor axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity (ɛ) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12 ≳ MV ≳ -22); however, dwarfs display much higher dispersions at all radii.

Analytical halo model of galactic conformity

NASA Astrophysics Data System (ADS)

Pahwa, Isha; Paranjape, Aseem

2017-09-01

We present a fully analytical halo model of colour-dependent clustering that incorporates the effects of galactic conformity in a halo occupation distribution framework. The model, based on our previous numerical work, describes conformity through a correlation between the colour of a galaxy and the concentration of its parent halo, leading to a correlation between central and satellite galaxy colours at fixed halo mass. The strength of the correlation is set by a tunable 'group quenching efficiency', and the model can separately describe group-level correlations between galaxy colour (1-halo conformity) and large-scale correlations induced by assembly bias (2-halo conformity). We validate our analytical results using clustering measurements in mock galaxy catalogues, finding that the model is accurate at the 10-20 per cent level for a wide range of luminosities and length-scales. We apply the formalism to interpret the colour-dependent clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We find good overall agreement between the data and a model that has 1-halo conformity at a level consistent with previous results based on an SDSS group catalogue, although the clustering data require satellites to be redder than suggested by the group catalogue. Within our modelling uncertainties, however, we do not find strong evidence of 2-halo conformity driven by assembly bias in SDSS clustering.

Star formation rates in isolated galaxies selected from the Two-Micron All-Sky Survey

NASA Astrophysics Data System (ADS)

Melnyk, O.; Karachentseva, V.; Karachentsev, I.

2015-08-01

We have considered the star formation properties of 1616 isolated galaxies from the 2MASS XSC (Extended Source Catalog) selected sample (2MIG) with the far-ultraviolet GALEX magnitudes. This sample was then compared with corresponding properties of isolated galaxies from the Local Orphan Galaxies (LOG) catalogue and paired galaxies. We found that different selection algorithms define different populations of isolated galaxies. The population of the LOG catalogue, selected from non-clustered galaxies in the Local Supercluster volume, mostly consists of low-mass spiral and late-type galaxies. The specific star formation rate (SSFR) upper limit in isolated and paired galaxies does not exceed the value of ˜dex(-9.4). This is probably common for galaxies of differing activity and environment (at least at z < 0.06). The fractions of quenched galaxies are nearly twice as high in the paired galaxy sample as in the 2MIG isolated galaxy sample. From the behaviour of (S)SFR versus M* relations we deduced that the characteristic value influencing evolutionary processes is the galaxy mass. However, the environmental influence is notable: paired massive galaxies with logM* > 11.5 have higher (S)SFR than isolated galaxies. Our results suggest that the environment helps to trigger the star formation in the highest mass galaxies. We found that the fraction of AGN in the paired sample is only a little higher than in our isolated galaxy sample. We assume that AGN phenomenon is probably defined by secular galaxy evolution.

Coma cluster ultradiffuse galaxies are not standard radio galaxies

NASA Astrophysics Data System (ADS)

Struble, Mitchell F.

2018-02-01

Matching members in the Coma cluster catalogue of ultradiffuse galaxies (UDGs) from SUBARU imaging with a very deep radio continuum survey source catalogue of the cluster using the Karl G. Jansky Very Large Array (VLA) within a rectangular region of ∼1.19 deg2 centred on the cluster core reveals matches consistent with random. An overlapping set of 470 UDGs and 696 VLA radio sources in this rectangular area finds 33 matches within a separation of 25 arcsec; dividing the sample into bins with separations bounded by 5, 10, 20 and 25 arcsec finds 1, 4, 17 and 11 matches. An analytical model estimate, based on the Poisson probability distribution, of the number of randomly expected matches within these same separation bounds is 1.7, 4.9, 19.4 and 14.2, each, respectively, consistent with the 95 per cent Poisson confidence intervals of the observed values. Dividing the data into five clustercentric annuli of 0.1° and into the four separation bins, finds the same result. This random match of UDGs with VLA sources implies that UDGs are not radio galaxies by the standard definition. Those VLA sources having integrated flux >1 mJy at 1.4 GHz in Miller, Hornschemeier and Mobasher without SDSS galaxy matches are consistent with the known surface density of background radio sources. We briefly explore the possibility that some unresolved VLA sources near UDGs could be young, compact, bright, supernova remnants of Type Ia events, possibly in the intracluster volume.

The Peculiarities in O-Type Galaxy Clusters

NASA Astrophysics Data System (ADS)

Panko, E. A.; Emelyanov, S. I.

We present the results of analysis of 2D distribution of galaxies in galaxy cluster fields. The Catalogue of Galaxy Clusters and Groups PF (Panko & Flin) was used as input observational data set. We selected open rich PF galaxy clusters, containing 100 and more galaxies for our study. According to Panko classification scheme open galaxy clusters (O-type) have no concentration to the cluster center. The data set contains both pure O-type clusters and O-type clusters with overdence belts, namely OL and OF types. According to Rood & Sastry and Struble & Rood ideas, the open galaxy clusters are the beginning stage of cluster evolution. We found in the O-type clusters some types of statistically significant regular peculiarities, such as two crossed belts or curved strip. We suppose founded features connected with galaxy clusters evolution and the distribution of DM inside the clusters.

Galaxy Zoo 1: data release of morphological classifications for nearly 900 000 galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linott, C.; Slosar, A.; Lintott, C.

Morphology is a powerful indicator of a galaxy's dynamical and merger history. It is strongly correlated with many physical parameters, including mass, star formation history and the distribution of mass. The Galaxy Zoo project collected simple morphological classifications of nearly 900,000 galaxies drawn from the Sloan Digital Sky Survey, contributed by hundreds of thousands of volunteers. This large number of classifications allows us to exclude classifier error, and measure the influence of subtle biases inherent in morphological classification. This paper presents the data collected by the project, alongside measures of classification accuracy and bias. The data are now publicly availablemore » and full catalogues can be downloaded in electronic format from http://data.galaxyzoo.org.« less

Relic galaxies: where are they?

NASA Astrophysics Data System (ADS)

Peralta de Arriba, L.; Quilis, V.; Trujillo, I.; Cebrián, M.; Balcells, M.

2017-03-01

The finding that massive galaxies grow with cosmic time fired the starting gun for the search of objects which could have survived up to the present day without suffering substantial changes (neither in their structures, neither in their stellar populations). Nevertheless, and despite the community efforts, up to now only one firm candidate to be considered one of these relics is known: NGC 1277. Curiously, this galaxy is located at the centre of one of the most rich near galaxy clusters: Perseus. Is its location a matter of chance? Should relic hunters focus their search on galaxy clusters? In order to reply this question, we have performed a simultaneous and analogous analysis using simulations (Millennium I-WMAP7) and observations (New York University Value-Added Galaxy Catalogue). Our results in both frameworks agree: it is more probable to find relics in high density environments.

Bibliography of Mock Trial Materials.

ERIC Educational Resources Information Center

National Inst. for Citizen Education in the Law, Washington, DC.

This catalog lists general articles on mock trials, information for arranging mock trial competitions, mock trial problem sets, and video tapes. The problem sets contain introductory material, applicable law, statements of facts, witness statements, and documents. The cases include issues in family, consumer, criminal, and immigration law. Several…

The Galics Project: Virtual Galaxy: from Cosmological N-body Simulations

NASA Astrophysics Data System (ADS)

Guiderdoni, B.

The GalICS project develops extensive semi-analytic post-processing of large cosmological simulations to describe hierarchical galaxy formation. The multiwavelength statistical properties of high-redshift and local galaxies are predicted within the large-scale structures. The fake catalogs and mock images that are generated from the outputs are used for the analysis and preparation of deep surveys. The whole set of results is now available in an on-line database that can be easily queried. The GalICS project represents a first step towards a 'Virtual Observatory of virtual galaxies'.

Blooming Trees: Substructures and Surrounding Groups of Galaxy Clusters

NASA Astrophysics Data System (ADS)

Yu, Heng; Diaferio, Antonaldo; Serra, Ana Laura; Baldi, Marco

2018-06-01

We develop the Blooming Tree Algorithm, a new technique that uses spectroscopic redshift data alone to identify the substructures and the surrounding groups of galaxy clusters, along with their member galaxies. Based on the estimated binding energy of galaxy pairs, the algorithm builds a binary tree that hierarchically arranges all of the galaxies in the field of view. The algorithm searches for buds, corresponding to gravitational potential minima on the binary tree branches; for each bud, the algorithm combines the number of galaxies, their velocity dispersion, and their average pairwise distance into a parameter that discriminates between the buds that do not correspond to any substructure or group, and thus eventually die, and the buds that correspond to substructures and groups, and thus bloom into the identified structures. We test our new algorithm with a sample of 300 mock redshift surveys of clusters in different dynamical states; the clusters are extracted from a large cosmological N-body simulation of a ΛCDM model. We limit our analysis to substructures and surrounding groups identified in the simulation with mass larger than 1013 h ‑1 M ⊙. With mock redshift surveys with 200 galaxies within 6 h ‑1 Mpc from the cluster center, the technique recovers 80% of the real substructures and 60% of the surrounding groups; in 57% of the identified structures, at least 60% of the member galaxies of the substructures and groups belong to the same real structure. These results improve by roughly a factor of two the performance of the best substructure identification algorithm currently available, the σ plateau algorithm, and suggest that our Blooming Tree Algorithm can be an invaluable tool for detecting substructures of galaxy clusters and investigating their complex dynamics.

Detecting effects of filaments on galaxy properties in the Sloan Digital Sky Survey III

NASA Astrophysics Data System (ADS)

Chen, Yen-Chi; Ho, Shirley; Mandelbaum, Rachel; Bahcall, Neta A.; Brownstein, Joel R.; Freeman, Peter E.; Genovese, Christopher R.; Schneider, Donald P.; Wasserman, Larry

2017-04-01

We study the effects of filaments on galaxy properties in the Sloan Digital Sky Survey (SDSS) Data Release 12 using filaments from the 'Cosmic Web Reconstruction' catalogue, a publicly available filament catalogue for SDSS. Since filaments are tracers of medium- to high-density regions, we expect that galaxy properties associated with the environment are dependent on the distance to the nearest filament. Our analysis demonstrates that a red galaxy or a high-mass galaxy tends to reside closer to filaments than a blue or low-mass galaxy. After adjusting the effect from stellar mass, on average, early-forming galaxies or large galaxies have a shorter distance to filaments than late-forming galaxies or small galaxies. For the main galaxy sample, all signals are very significant (>6σ). For the LOWZ and CMASS sample, the stellar mass and size are significant (>2σ). The filament effects we observe persist until z = 0.7 (the edge of the CMASS sample). Comparing our results to those using the galaxy distances from redMaPPer galaxy clusters as a reference, we find a similar result between filaments and clusters. Moreover, we find that the effect of clusters on the stellar mass of nearby galaxies depends on the galaxy's filamentary environment. Our findings illustrate the strong correlation of galaxy properties with proximity to density ridges, strongly supporting the claim that density ridges are good tracers of filaments.

The Atacama Cosmology Telescope: Dusty Star-Forming Galaxies and Active Galactic Nuclei in the Southern Survey

NASA Technical Reports Server (NTRS)

Marsden, Danica; Gralla, Megan; Marriage, Tobias A.; Switzer, Eric R.; Partridge, Bruce; Massardi, Marcella; Morales, Gustavo; Addison, Graeme; Bond, J. Richard; Crighton, Devin;

The Atacama Cosmology Telescope: Dusty Star-Forming Galaxies and Active Galactic Nuclei in the Southern Survey

NASA Technical Reports Server (NTRS)

Marsden, Danica; Gralla, Megan; Marriage, Tobias A.; Switzer, Eric R.; Partridge, Bruce; Massardi, Marcella; Morales, Gustavo; Addison, Graeme; Bond, J. Richard; Crichton, Devin;

Matching radio catalogues with realistic geometry: application to SWIRE and ATLAS

NASA Astrophysics Data System (ADS)

Fan, Dongwei; Budavári, Tamás; Norris, Ray P.; Hopkins, Andrew M.

2015-08-01

Cross-matching catalogues at different wavelengths is a difficult problem in astronomy, especially when the objects are not point-like. At radio wavelengths, an object can have several components corresponding, for example, to a core and lobes. Considering not all radio detections correspond to visible or infrared sources, matching these catalogues can be challenging. Traditionally, this is done by eye for better quality, which does not scale to the large data volumes expected from the next-generation of radio telescopes. We present a novel automated procedure, using Bayesian hypothesis testing, to achieve reliable associations by explicit modelling of a particular class of radio-source morphology. The new algorithm not only assesses the likelihood of an association between data at two different wavelengths, but also tries to assess whether different radio sources are physically associated, are double-lobed radio galaxies, or just distinct nearby objects. Application to the Spitzer Wide-Area Infrared Extragalactic and Australia Telescope Large Area Survey CDF-S catalogues shows that this method performs well without human intervention.

Street Law Mock Trial Manual.

ERIC Educational Resources Information Center

McGuire, Patricia, Ed.; O'Brien, Edward L.; Arbetman, Lee; Mills, Vivian H.; Pannell, Andrew

Designed to facilitate the expanded use of mock trials, this manual is divided into two principle sections--a teacher's guide and a student's guide. The teacher's guide contains specific advice to teachers on all aspects of preparing for a mock trial and seven specific lesson plans for a 2- to 3-week mock trial unit. Each lesson contains…

VizieR Online Data Catalog: HI supershells catalogue (Suad+, 2014)

NASA Astrophysics Data System (ADS)

Suad, L. A.; Caiafa, C. F.; Arnal, E. M.; Cichowolski, S.

2014-02-01

The HI supershells catalogue was carried out making use of the Leiden-Argentine-Bonn (LAB) HI survey in the outer part of the Galaxy. The identification of the supershell candidates was made using a combination of two techniques: a visual inspection one plus an automatic searching algorithm. A total of 566 supershell candidates were identified. Most of them (347) are located in the second galactic quadrant, while 219 were found in the third one. (1 data file).

Implementing newborn mock codes.

PubMed

Blakely, Teresa Gail

2007-01-01

This article describes the implementation of a newborn mock code program. Although the Neonatal Resuscitation Program (NRP) is one of the most widely used health education programs in the world and is required for most hospital providers who attend deliveries, research tells us that retention of NRP skills deteriorates rapidly after completion of the course. NRP requires coordination and cooperation among all providers; however, a lack of leadership and teamwork during resuscitation (often associated with a lack of confidence) has been noted. Implementation of newborn mock code scenarios can encourage teamwork, communication, skills building, and increased confidence levels of providers. Mock codes can help providers become strong team members and team leaders by helping them be better prepared for serious situations in the delivery room. Implementation of newborn mock codes can be effectively accomplished with appropriate planning and consideration for adult learning behaviors.

Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

DOE PAGES

Clampitt, J.; S?nchez, C.; Kwan, J.; ...

2016-11-22

We present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales $0.09 < R < 15$ Mpc/$h$, including all lenses over a wide redshift range $0.2 < z < 0.8$. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtainmore » consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.« less

Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clampitt, J.; S?nchez, C.; Kwan, J.

We present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales $0.09 < R < 15$ Mpc/$h$, including all lenses over a wide redshift range $0.2 < z < 0.8$. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtainmore » consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.« less

Extended Source/Galaxy All Sky 2

NASA Image and Video Library

2003-03-27

This panoramic view encompasses the entire sky and reveals the distribution of galaxies beyond the Milky Way galaxy, which astronomers call extended sources, as observed by Two Micron All-Sky Survey. The image is assembled from a database of over 1.6 million galaxies listed in the survey’s All-Sky Survey Extended Source Catalog; more than half of the galaxies have never before been catalogued. The colors represent how the many galaxies appear at three distinct wavelengths of infrared light (blue at 1.2 microns, green at 1.6 microns, and red at 2.2 microns). Quite evident are the many galactic clusters and superclusters, as well as some streamers composing the large-scale structure of the nearby universe. The blue overlay represents the very close and bright stars from our own Milky Way galaxy. In this projection, the bluish Milky Way lies predominantly toward the upper middle and edges of the image. http://photojournal.jpl.nasa.gov/catalog/PIA04251

A Catalogue of Galaxies Having Radial Velocities: Volume 15: Part 7

NASA Technical Reports Server (NTRS)

Fredrick, L. W.; Gutsch, W. A.

1974-01-01

A tabulation of galaxies which have radial velocities is presented. The parameters of each galaxy are: (1) an abbreviation for the catalog designation, (2) RA(1950), (3) Dec. (1950), (4) new galactic longitude, (5) new galactic latitude, (6) morphological type, (7) magnitude, (8) observed radial velocity in kilometers per second (9) radial velocity corrected for solar motion, and (10) estimated error in radial velocity in kilometers per second.

Morpho-z: improving photometric redshifts with galaxy morphology

NASA Astrophysics Data System (ADS)

Soo, John Y. H.; Moraes, Bruno; Joachimi, Benjamin; Hartley, William; Lahav, Ofer; Charbonnier, Aldée; Makler, Martín; Pereira, Maria E. S.; Comparat, Johan; Erben, Thomas; Leauthaud, Alexie; Shan, Huanyuan; Van Waerbeke, Ludovic

2018-04-01

We conduct a comprehensive study of the effects of incorporating galaxy morphology information in photometric redshift estimation. Using machine learning methods, we assess the changes in the scatter and outlier fraction of photometric redshifts when galaxy size, ellipticity, Sérsic index, and surface brightness are included in training on galaxy samples from the SDSS and the CFHT Stripe-82 Survey (CS82). We show that by adding galaxy morphological parameters to full ugriz photometry, only mild improvements are obtained, while the gains are substantial in cases where fewer passbands are available. For instance, the combination of grz photometry and morphological parameters almost fully recovers the metrics of 5-band photometric redshifts. We demonstrate that with morphology it is possible to determine useful redshift distribution N(z) of galaxy samples without any colour information. We also find that the inclusion of quasar redshifts and associated object sizes in training improves the quality of photometric redshift catalogues, compensating for the lack of a good star-galaxy separator. We further show that morphological information can mitigate biases and scatter due to bad photometry. As an application, we derive both point estimates and posterior distributions of redshifts for the official CS82 catalogue, training on morphology and SDSS Stripe-82 ugriz bands when available. Our redshifts yield a 68th percentile error of 0.058(1 + z), and a outlier fraction of 5.2 per cent. We further include a deep extension trained on morphology and single i-band CS82 photometry.

Gradient pattern analysis applied to galaxy morphology

NASA Astrophysics Data System (ADS)

Rosa, R. R.; de Carvalho, R. R.; Sautter, R. A.; Barchi, P. H.; Stalder, D. H.; Moura, T. C.; Rembold, S. B.; Morell, D. R. F.; Ferreira, N. C.

2018-06-01

Gradient pattern analysis (GPA) is a well-established technique for measuring gradient bilateral asymmetries of a square numerical lattice. This paper introduces an improved version of GPA designed for galaxy morphometry. We show the performance of the new method on a selected sample of 54 896 objects from the SDSS-DR7 in common with Galaxy Zoo 1 catalogue. The results suggest that the second gradient moment, G2, has the potential to dramatically improve over more conventional morphometric parameters. It separates early- from late-type galaxies better (˜ 90 per cent) than the CAS system (C˜ 79 per cent, A˜ 50 per cent, S˜ 43 per cent) and a benchmark test shows that it is applicable to hundreds of thousands of galaxies using typical processing systems.

Galaxy Zoo: morphological classifications for 120 000 galaxies in HST legacy imaging

NASA Astrophysics Data System (ADS)

Willett, Kyle W.; Galloway, Melanie A.; Bamford, Steven P.; Lintott, Chris J.; Masters, Karen L.; Scarlata, Claudia; Simmons, B. D.; Beck, Melanie; Cardamone, Carolin N.; Cheung, Edmond; Edmondson, Edward M.; Fortson, Lucy F.; Griffith, Roger L.; Häußler, Boris; Han, Anna; Hart, Ross; Melvin, Thomas; Parrish, Michael; Schawinski, Kevin; Smethurst, R. J.; Smith, Arfon M.

2017-02-01

We present the data release paper for the Galaxy Zoo: Hubble (GZH) project. This is the third phase in a large effort to measure reliable, detailed morphologies of galaxies by using crowdsourced visual classifications of colour-composite images. Images in GZH were selected from various publicly released Hubble Space Telescope legacy programmes conducted with the Advanced Camera for Surveys, with filters that probe the rest-frame optical emission from galaxies out to z ˜ 1. The bulk of the sample is selected to have mI814W < 23.5, but goes as faint as mI814W < 26.8 for deep images combined over five epochs. The median redshift of the combined samples is = 0.9 ± 0.6, with a tail extending out to z ≃ 4. The GZH morphological data include measurements of both bulge- and disc-dominated galaxies, details on spiral disc structure that relate to the Hubble type, bar identification, and numerous measurements of clump identification and geometry. This paper also describes a new method for calibrating morphologies for galaxies of different luminosities and at different redshifts by using artificially redshifted galaxy images as a baseline. The GZH catalogue contains both raw and calibrated morphological vote fractions for 119 849 galaxies, providing the largest data set to date suitable for large-scale studies of galaxy evolution out to z ˜ 1.

Modelling galaxy clustering on small scales to tighten constraints on dark energy and modified gravity

NASA Astrophysics Data System (ADS)

Wang, Yun

2017-01-01

We present a new approach to measuring cosmic expansion history and growth rate of large-scale structure using the anisotropic two-dimensional galaxy correlation function (2DCF) measured from data; it makes use of the empirical modelling of small-scale galaxy clustering derived from numerical simulations by Zheng et al. We validate this method using mock catalogues, before applying it to the analysis of the CMASS sample from the Sloan Digital Sky Survey Data Release 10 of the Baryon Oscillation Spectroscopic Survey. We find that this method enables accurate and precise measurements of cosmic expansion history and growth rate of large-scale structure. Modelling the 2DCF fully including non-linear effects and redshift space distortions in the scale range of 16-144 h-1 Mpc, we find H(0.57)rs(zd)/c = 0.0459 ± 0.0006, DA(0.57)/rs(zd) = 9.011 ± 0.073, and fg(0.57)σ8(0.57) = 0.476 ± 0.050, which correspond to precisions of 1.3 per cent, 0.8 per cent, and 10.5 per cent, respectively. We have defined rs(zd) to be the sound horizon at the drag epoch computed using a simple integral, fg(z) as the growth rate at redshift z, and σ8(z) as the matter power spectrum normalization on 8 h-1 Mpc scale at z. We find that neglecting the small-scale information significantly weakens the constraints on H(z) and DA(z), and leads to a biased estimate of fg(z). Our results indicate that we can significantly tighten constraints on dark energy and modified gravity by reliably modelling small-scale galaxy clustering.

Imaging Cold Gas to 1 kpc scales in high-redshift galaxies with the ngVLA

NASA Astrophysics Data System (ADS)

Casey, Caitlin; Narayanan, Desika; Dave, Romeel; Hung, Chao-Ling; Champagne, Jaclyn; Carilli, Chris Luke; Decarli, Roberto; Murphy, Eric J.; Popping, Gergo; Riechers, Dominik; Somerville, Rachel S.; Walter, Fabian

2017-01-01

The next generation Very Large Array (ngVLA) will revolutionize our understanding of the distant Universe via the detection of cold molecular gas in the first galaxies. Its impact on studies of galaxy characterization via detailed gas dynamics will provide crucial insight on dominant physical drivers for star-formation in high redshift galaxies, including the exchange of gas from scales of the circumgalactic medium down to resolved clouds on mass scales of ~10^5 M_sun. In this study, we employ a series of high-resolution, cosmological, hydrodynamic zoom simulations from the MUFASA simulation suite and a CASA simulator to generate mock ngVLA observations. Based on a direct comparison between the inferred results from our mock observations and the cosmological simulations, we investigate the capabilities of ngVLA to constrain the mode of star formation, dynamical mass, and molecular gas kinematics in individual high-redshift galaxies using cold gas tracers like CO(1-0) and CO(2-1). Using the Despotic radiative transfer code that encompasses simultaneous thermal and statistical equilibrium in calculating the molecular and atomic level populations, we generate parallel mock observations of high-J transitions of CO and C+ from ALMA for comparison. The factor of 100 times improvement in mapping speed for the ngVLA beyond the Jansky VLA and the proposed ALMA Band 1 will make these detailed, high-resolution imaging and kinematic studies routine at z=2 and beyond.

A cross-correlation-based estimate of the galaxy luminosity function

NASA Astrophysics Data System (ADS)

van Daalen, Marcel P.; White, Martin

2018-06-01

We extend existing methods for using cross-correlations to derive redshift distributions for photometric galaxies, without using photometric redshifts. The model presented in this paper simultaneously yields highly accurate and unbiased redshift distributions and, for the first time, redshift-dependent luminosity functions, using only clustering information and the apparent magnitudes of the galaxies as input. In contrast to many existing techniques for recovering unbiased redshift distributions, the output of our method is not degenerate with the galaxy bias b(z), which is achieved by modelling the shape of the luminosity bias. We successfully apply our method to a mock galaxy survey and discuss improvements to be made before applying our model to real data.

Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release

NASA Astrophysics Data System (ADS)

Driver, S. P.; Hill, D. T.; Kelvin, L. S.; Robotham, A. S. G.; Liske, J.; Norberg, P.; Baldry, I. K.; Bamford, S. P.; Hopkins, A. M.; Loveday, J.; Peacock, J. A.; Andrae, E.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cameron, E.; Ching, J. H. Y.; Colless, M.; Conselice, C. J.; Croom, S. M.; Cross, N. J. G.; de Propris, R.; Dye, S.; Drinkwater, M. J.; Ellis, S.; Graham, Alister W.; Grootes, M. W.; Gunawardhana, M.; Jones, D. H.; van Kampen, E.; Maraston, C.; Nichol, R. C.; Parkinson, H. R.; Phillipps, S.; Pimbblet, K.; Popescu, C. C.; Prescott, M.; Roseboom, I. G.; Sadler, E. M.; Sansom, A. E.; Sharp, R. G.; Smith, D. J. B.; Taylor, E.; Thomas, D.; Tuffs, R. J.; Wijesinghe, D.; Dunne, L.; Frenk, C. S.; Jarvis, M. J.; Madore, B. F.; Meyer, M. J.; Seibert, M.; Staveley-Smith, L.; Sutherland, W. J.; Warren, S. J.

2011-05-01

The Galaxy and Mass Assembly (GAMA) survey has been operating since 2008 February on the 3.9-m Anglo-Australian Telescope using the AAOmega fibre-fed spectrograph facility to acquire spectra with a resolution of R≈ 1300 for 120 862 Sloan Digital Sky Survey selected galaxies. The target catalogue constitutes three contiguous equatorial regions centred at 9h (G09), 12h (G12) and 14.5h (G15) each of 12 × 4 deg2 to limiting fluxes of rpet < 19.4, rpet < 19.8 and rpet < 19.4 mag, respectively (and additional limits at other wavelengths). Spectra and reliable redshifts have been acquired for over 98 per cent of the galaxies within these limits. Here we present the survey footprint, progression, data reduction, redshifting, re-redshifting, an assessment of data quality after 3 yr, additional image analysis products (including ugrizYJHK photometry, Sérsic profiles and photometric redshifts), observing mask and construction of our core survey catalogue (GamaCore). From this we create three science-ready catalogues: GamaCoreDR1 for public release, which includes data acquired during year 1 of operations within specified magnitude limits (2008 February to April); GamaCoreMainSurvey containing all data above our survey limits for use by the GAMA Team and collaborators; and GamaCoreAtlasSV containing year 1, 2 and 3 data matched to Herschel-ATLAS science demonstration data. These catalogues along with the associated spectra, stamps and profiles can be accessed via the GAMA website:

Extended Source/Galaxy All Sky 1

NASA Image and Video Library

2003-03-27

This panoramic view of the entire sky reveals the distribution of galaxies beyond our Milky Way galaxy, which astronomers call extended sources, as observed by Two Micron All-Sky Survey. The image is constructed from a database of over 1.6 million galaxies listed in the survey's Extended Source Catalog; more than half of the galaxies have never before been catalogued. The image is a representation of the relative brightnesses of these million-plus galaxies, all observed at a wavelength of 2.2 microns. The brightest and nearest galaxies are represented in blue, and the faintest, most distant ones are in red. This color scheme gives insights into the three dimensional large-scale structure of the nearby universe with the brightest, closest clusters and superclusters showing up as the blue and bluish-white features. The dark band in this image shows the area of the sky where our Milky Way galaxy blocks our view of distant objects, which, in this projection, lies predominantly along the edges of the image. http://photojournal.jpl.nasa.gov/catalog/PIA04252

The invisible AGN catalogue: a mid-infrared-radio selection method for optically faint active galactic nuclei

NASA Astrophysics Data System (ADS)

Truebenbach, Alexandra E.; Darling, Jeremy

2017-06-01

A large fraction of active galactic nuclei (AGN) are 'invisible' in extant optical surveys due to either distance or dust-obscuration. The existence of this large population of dust-obscured, infrared (IR)-bright AGN is predicted by models of galaxy-supermassive black hole coevolution and is required to explain the observed X-ray and IR backgrounds. Recently, IR colour cuts with Wide-field Infrared Survey Explorer have identified a portion of this missing population. However, as the host galaxy brightness relative to that of the AGN increases, it becomes increasingly difficult to differentiate between IR emission originating from the AGN and from its host galaxy. As a solution, we have developed a new method to select obscured AGN using their 20-cm continuum emission to identify the objects as AGN. We created the resulting invisible AGN catalogue by selecting objects that are detected in AllWISE (mid-IR) and FIRST (20 cm), but are not detected in SDSS (optical) or 2MASS (near-IR), producing a final catalogue of 46 258 objects. 30 per cent of the objects are selected by existing selection methods, while the remaining 70 per cent represent a potential previously unidentified population of candidate AGN that are missed by mid-IR colour cuts. Additionally, by relying on a radio continuum detection, this technique is efficient at detecting radio-loud AGN at z ≥ 0.29, regardless of their level of dust obscuration or their host galaxy's relative brightness.

Automatic Detection of Galaxy Type From Datasets of Galaxies Image Based on Image Retrieval Approach.

PubMed

Abd El Aziz, Mohamed; Selim, I M; Xiong, Shengwu

2017-06-30

This paper presents a new approach for the automatic detection of galaxy morphology from datasets based on an image-retrieval approach. Currently, there are several classification methods proposed to detect galaxy types within an image. However, in some situations, the aim is not only to determine the type of galaxy within the queried image, but also to determine the most similar images for query image. Therefore, this paper proposes an image-retrieval method to detect the type of galaxies within an image and return with the most similar image. The proposed method consists of two stages, in the first stage, a set of features is extracted based on shape, color and texture descriptors, then a binary sine cosine algorithm selects the most relevant features. In the second stage, the similarity between the features of the queried galaxy image and the features of other galaxy images is computed. Our experiments were performed using the EFIGI catalogue, which contains about 5000 galaxies images with different types (edge-on spiral, spiral, elliptical and irregular). We demonstrate that our proposed approach has better performance compared with the particle swarm optimization (PSO) and genetic algorithm (GA) methods.

Philadelphus L.: mock orange

Treesearch

Nancy L. Shaw; Emerenciana G. Hurd; Peter F. Stickney

2008-01-01

The mock oranges - Philadelphus spp. - have been placed in several families: Saxifragaceae (Harrington 1954), Hydrangeaceae (Hitchcock and others 1961), and more recently, the Philadelphaceae (Hickman 1993). Hydrangeaceae, however, is the most widely accepted placement (Cronquist and others 1997; USDA NRCS 2001). There are about 50 to 65 species of mock orange,...

Angular power spectrum of galaxies in the 2MASS Redshift Survey

NASA Astrophysics Data System (ADS)

Ando, Shin'ichiro; Benoit-Lévy, Aurélien; Komatsu, Eiichiro

2018-02-01

We present the measurement and interpretation of the angular power spectrum of nearby galaxies in the 2MASS Redshift Survey catalogue with spectroscopic redshifts up to z ≈ 0.1. We detect the angular power spectrum up to a multipole of ℓ ≈ 1000. We find that the measured power spectrum is dominated by galaxies living inside nearby galaxy clusters and groups. We use the halo occupation distribution (HOD) formalism to model the power spectrum, obtaining a fit with reasonable parameters. These HOD parameters are in agreement with the 2MASS galaxy distribution we measure towards the known nearby galaxy clusters, confirming validity of our analysis.

VizieR Online Data Catalog: REFLEX Galaxy Cluster Survey catalogue (Boehringer+, 2004)

NASA Astrophysics Data System (ADS)

Boehringer, H.; Schuecker, P.; Guzzo, L.; Collins, C. A.; Voges, W.; Cruddace, R. G.; Ortiz-Gil, A.; Chincarini, G.; de Grandi, S.; Edge, A. C.; MacGillivray, H. T.; Neumann, D. M.; Schindler, S.; Shaver, P.

2004-05-01

The following tables provide the catalogue as well as several data files necessary to reproduce the sample preparation. These files are also required for the cosmological modeling of these observations in e.g. the study of the statistics of the large-scale structure of the matter distribution in the Universe and related cosmological tests. (13 data files).

Galaxy Clustering Topology in the Sloan Digital Sky Survey Main Galaxy Sample: A Test for Galaxy Formation Models

NASA Astrophysics Data System (ADS)

Choi, Yun-Young; Park, Changbom; Kim, Juhan; Gott, J. Richard, III; Weinberg, David H.; Vogeley, Michael S.; Kim, Sungsoo S.; SDSS Collaboration

2010-09-01

We measure the topology of the main galaxy distribution using the Seventh Data Release of the Sloan Digital Sky Survey, examining the dependence of galaxy clustering topology on galaxy properties. The observational results are used to test galaxy formation models. A volume-limited sample defined by Mr < -20.19 enables us to measure the genus curve with an amplitude of G = 378 at 6 h -1 Mpc smoothing scale, with 4.8% uncertainty including all systematics and cosmic variance. The clustering topology over the smoothing length interval from 6 to 10 h -1 Mpc reveals a mild scale dependence for the shift (Δν) and void abundance (AV ) parameters of the genus curve. We find substantial bias in the topology of galaxy clustering with respect to the predicted topology of the matter distribution, which varies with luminosity, morphology, color, and the smoothing scale of the density field. The distribution of relatively brighter galaxies shows a greater prevalence of isolated clusters and more percolated voids. Even though early (late)-type galaxies show topology similar to that of red (blue) galaxies, the morphology dependence of topology is not identical to the color dependence. In particular, the void abundance parameter AV depends on morphology more strongly than on color. We test five galaxy assignment schemes applied to cosmological N-body simulations of a ΛCDM universe to generate mock galaxies: the halo-galaxy one-to-one correspondence model, the halo occupation distribution model, and three implementations of semi-analytic models (SAMs). None of the models reproduces all aspects of the observed clustering topology; the deviations vary from one model to another but include statistically significant discrepancies in the abundance of isolated voids or isolated clusters and the amplitude and overall shift of the genus curve. SAM predictions of the topology color dependence are usually correct in sign but incorrect in magnitude. Our topology tests indicate that, in

Power spectrum estimation from peculiar velocity catalogues

NASA Astrophysics Data System (ADS)

Macaulay, E.; Feldman, H. A.; Ferreira, P. G.; Jaffe, A. H.; Agarwal, S.; Hudson, M. J.; Watkins, R.

2012-09-01

The peculiar velocities of galaxies are an inherently valuable cosmological probe, providing an unbiased estimate of the distribution of matter on scales much larger than the depth of the survey. Much research interest has been motivated by the high dipole moment of our local peculiar velocity field, which suggests a large-scale excess in the matter power spectrum and can appear to be in some tension with the Λ cold dark matter (ΛCDM) model. We use a composite catalogue of 4537 peculiar velocity measurements with a characteristic depth of 33 h-1 Mpc to estimate the matter power spectrum. We compare the constraints with this method, directly studying the full peculiar velocity catalogue, to results by Macaulay et al., studying minimum variance moments of the velocity field, as calculated by Feldman, Watkins & Hudson. We find good agreement with the ΛCDM model on scales of k > 0.01 h Mpc-1. We find an excess of power on scales of k < 0.01 h Mpc-1 with a 1σ uncertainty which includes the ΛCDM model. We find that the uncertainty in excess at these scales is larger than an alternative result studying only moments of the velocity field, which is due to the minimum variance weights used to calculate the moments. At small scales, we are able to clearly discriminate between linear and non-linear clustering in simulated peculiar velocity catalogues and find some evidence (although less clear) for linear clustering in the real peculiar velocity data.

Reconstructing The Star Formation Histories Of Galaxies Through Sed Fitting Using The Dense Basis Method

NASA Astrophysics Data System (ADS)

Iyer, Kartheik; Gawiser, Eric

2017-06-01

The Dense Basis SED fitting method reveals previously inaccessible information about the number and duration of star formation episodes and the timing of stellar mass assembly as well as uncertainties in these quantities, in addition to accurately recovering traditional SED parameters including M*, SFR and dust attenuation. This is done using basis Star Formation Histories (SFHs) chosen by comparing the goodness-of-fit of mock galaxy SEDs to the goodness-of-reconstruction of their SFHs, trained and validated using three independent datasets of mock galaxies at z=1 from SAMs, Hydrodynamic simulations and stochastic realizations. Of the six parametrizations of SFHs considered, we reject the traditional parametrizations of constant and exponential SFHs and suggest four novel improvements, quantifying the bias and scatter of each parametrization. We then apply the method to a sample of 1100 CANDELS GOODS-S galaxies at 1galaxies in our sample exhibit multiple episodes of star formation, with this fraction decreasing above M*>10^9 M_sun, in contrast to current simulations. About 40% of the CANDEL galaxies have SFHs whose maximum occurs at or near the epoch of observation. These results are presented in Iyer and Gawiser (2017, ApJ 838 127), available at https://arxiv.org/abs/1702.04371

VizieR Online Data Catalog: Friends-of-friends galaxy group finder (Tempel+, 2016)

NASA Astrophysics Data System (ADS)

Tempel, E.; Kipper, R.; Tamm, A.; Gramann, M.; Einasto, M.; Sepp, T.; Tuvikene, T.

2016-01-01

To delineate galaxy groups in the local Universe, we used galaxy data from the extragalactic distance database (EDD2; Tully et al., 2009AJ....138..323T). The sample encompasses three datasets. As the main source, we used the Two Micron All Sky Survey (Skrutskie et al. 2006AJ....131.1163S, Cat. VII/233) Redshift Survey (2MRS) galaxies brighter than 11.75 mag in the Ks band (for a description of the catalogue, see Huchra et al., 2012, Cat. J/ApJS/199/26). We only used galaxies that are securely off the Galactic plane: Galactic latitude |b|>5°. Since the galaxy sample becomes extremely sparse farther away, we only used galaxies with a cosmic microwave background (CMB) corrected redshift z=0...0.1 (up to 430Mpc). This selection restricts our 2MRS sample to 43480 galaxies. For our analysis, we complemented the main 2MRS sample with two other sources. From the CosmicFlows-2 survey that contains 8198 galaxies with redshift-independent distance estimates (CF2; Tully et al., 2013, Cat. J/AJ/146/86), we added 3627 (of these, 2799 galaxies do not have a measured Ks magnitude). In addition, we made use of the 2M++ catalogue Lavaux & Hudson (2011, Cat. J/MNRAS/416/2840), which combines elements from the 2MRS, the 6DF Galaxy Survey (Jones et al. 2009MNRAS.399..683J, Cat. VII/259), and the Sloan Digital Sky Survey (York et al., 2000AJ....120.1579Y). Of the 64745 galaxies of the 2M++, we added 31271 galaxies down to Ks<12.54, which extends the sample well beyond the 2MRS magnitude limit. Our final galaxy dataset includes 78378 galaxies. (4 data files).

The Smallest Galaxies in the Universe: Investigating the Origins of Ultra-faint Galaxies

NASA Astrophysics Data System (ADS)

Qi, Yuewen; Graus, Andrew; Bullock, James

2018-01-01

One outstanding question in cosmology is, what are the smallest galaxies that can form? The answer to this question can tell us much about galaxy formation, and even of the properties of dark matter itself. A candidate for the smallest galaxies that can form are the ultrafaint galaxies. The star formation of ultrafaints appears to have been shut off during the epoch of reionization, when radiation from the first stars ionized all the free hydrogen in the universe. This would imply ultrafaints should exist everywhere in the universe. However, we can only observe ultrafaints as satellites of the Milky Way, due to their low brightness. This will change with the next generation of telescopes such as the Large Synoptic Survey Telescope (LSST). The focus of this work is to predict the number of ultrafaints that should be seen with future surveys. To that end, we use the ELVIS suite, which contains 14 dark matter only simulations of Local Group like systems containing a Milky Way and Andromeda-like galaxy and the substructure out to around 1 Mpc of the barycenter. We mock observe the simulations in order to mimic current surveys such as the Sloan Digital Sky Survey (SDSS), and the Dark Energy Survey (DES), and use the population of galaxies found by those surveys to project the population of dwarf galaxies out beyond the virial radius of either galaxy. This number will depend sensitively on the formation mechanism of ultrafaint dwarfs, and comparisons of future surveys to this work could help rule out certain formation scenarios.

A 2 epoch proper motion catalogue from the UKIDSS Large Area Survey

NASA Astrophysics Data System (ADS)

Smith, Leigh; Lucas, Phil; Burningham, Ben; Jones, Hugh; Pinfield, David; Smart, Ricky; Andrei, Alexandre

2013-04-01

The UKIDSS Large Area Survey (LAS) began in 2005, with the start of the UKIDSS program as a 7 year effort to survey roughly 4000 square degrees at high galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of 2-epoch J band observations, with epoch baselines ranging from 2 to 7 years. We present a proper motion catalogue for the 1500 square degrees of the 2 epoch LAS data, which includes some 800,000 sources with motions detected above the 5σ level. We developed a bespoke proper motion pipeline which applies a source-unique second order polynomial transformation to UKIDSS array coordinates of each source to counter potential local non-uniformity in the focal plane. Our catalogue agrees well with the proper motion data supplied in the current WFCAM Science Archive (WSA) DR9 catalogue where there is overlap, and in various optical catalogues, but it benefits from some improvements. One improvement is that we provide absolute proper motions, using LAS galaxies for the relative to absolute correction. Also, by using unique, local, 2nd order polynomial tranformations, as opposed to the linear transformations in the WSA, we correct better for any local distortions in the focal plane, not including the radial distortion that is removed by their pipeline.

CGM Evolution of a Simulated Dwarf Galaxy

NASA Astrophysics Data System (ADS)

Sheehan-Klenk, Patrick; Christensen, Charlotte

2018-06-01

The circumgalactic medium (CGM), which is fed by galactic outflows, is intrinsically connected to star formation and galactic evolution. We followed the evolution of the CGM of a simulated dwarf galaxy of mass 4.75 × 1010 solar masses., through five timesteps corresponding to z = 3, 2, 1, 0.5, 0.15. The simulation includes metal line cooling, metal diffusion, and supernova feedback, and the resulting galaxy has a realistic stellar mass and metallicity. We measured the surface densities of HI, CIV and OVI in the CGM gas composition and analyzed their trends in relation to the galaxy's evolution. Additionally, we created mock absorption line spectra, which we used to find the mean equivalent width for sight lines spaced 0.1R/Rvir apart. From this analysis, we saw there was high metallicity at large radii, and over time the CGM cooled and became more ordered. We note the impact of a merger with a smaller galaxy at z = 0.5. We compare these results to observations.

Catalogues of planetary nebulae.

NASA Astrophysics Data System (ADS)

Acker, A.

Firstly, the general requirements concerning catalogues are studied for planetary nebulae, in particular concerning the objects to be included in a catalogue of PN, their denominations, followed by reflexions about the afterlife and comuterized versions of a catalogue. Then, the basic elements constituting a catalogue of PN are analyzed, and the available data are looked at each time.

Probing galaxy assembly bias with LRG weak lensing observations

NASA Astrophysics Data System (ADS)

Niemiec, A.; Jullo, E.; Montero-Dorta, A. D.; Prada, F.; Rodriguez-Torres, S.; Perez, E.; Klypin, A.; Erben, T.; Makler, M.; Moraes, B.; Pereira, M. E. S.; Shan, H.

2018-06-01

In Montero-Dorta et al., we show that luminous red galaxies (LRGs) from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) at z ˜ 0.55 can be divided into two groups based on their star formation histories. So-called fast-growing LRGs assemble 80 per cent of their stellar mass at z ˜ 5, whereas slow-growing LRGs reach the same evolutionary state at z ˜ 1.5. We further demonstrate that these two subpopulations present significantly different clustering properties on scales of ˜1-30 Mpc. Here, we measure the mean halo mass of each subsample using the galaxy-galaxy lensing technique, in the ˜ 190°^2 overlap of the LRG catalogue and the CS82 and CFHTLenS shear catalogues. We show that fast- and slow-growing LRGs have similar lensing profiles, which implies that they live in haloes of similar mass: log (M_halo^fast/h^{-1}M_{⊙}) = 12.85^{+0.16}_{-0.26} and log (M_halo^slow/h^{-1}M_{⊙}) =12.92^{+0.16}_{-0.22}. This result, combined with the clustering difference, suggests the existence of galaxy assembly bias, although the effect is too subtle to be definitively proven, given the errors on our current weak-lensing measurement. We show that this can soon be achieved with upcoming surveys like DES.

LoCuSS: weak-lensing mass calibration of galaxy clusters

NASA Astrophysics Data System (ADS)

Okabe, Nobuhiro; Smith, Graham P.

2016-10-01

We present weak-lensing mass measurements of 50 X-ray luminous galaxy clusters at 0.15 ≤ z ≤ 0.3, based on uniform high-quality observations with Suprime-Cam mounted on the 8.2-m Subaru telescope. We pay close attention to possible systematic biases, aiming to control them at the ≲4 per cent level. The dominant source of systematic bias in weak-lensing measurements of the mass of individual galaxy clusters is contamination of background galaxy catalogues by faint cluster and foreground galaxies. We extend our conservative method for selecting background galaxies with (V - I') colours redder than the red sequence of cluster members to use a colour-cut that depends on cluster-centric radius. This allows us to define background galaxy samples that suffer ≤1 per cent contamination, and comprise 13 galaxies per square arcminute. Thanks to the purity of our background galaxy catalogue, the largest systematic that we identify in our analysis is a shape measurement bias of 3 per cent, that we measure using simulations that probe weak shears up to g = 0.3. Our individual cluster mass and concentration measurements are in excellent agreement with predictions of the mass-concentration relation. Equally, our stacked shear profile is in excellent agreement with the Navarro Frenk and White profile. Our new Local Cluster Substructure Survey mass measurements are consistent with the Canadian Cluster Cosmology Project and Cluster Lensing And Supernova Survey with Hubble surveys, and in tension with the Weighing the Giants at ˜1σ-2σ significance. Overall, the consensus at z ≤ 0.3 that is emerging from these complementary surveys represents important progress for cluster mass calibration, and augurs well for cluster cosmology.

The Far-Infrared Properties of the Most Isolated Galaxies

NASA Astrophysics Data System (ADS)

Lisenfeld, U.; Verdes-Montenegro, L.; Sulentic, J.; Leon, S.; Espada, D.; Bergond, G.; García, E.; Sabater, J.; Santander-Vela, J. D.; Verley, S.

2007-05-01

A long-standing question in galaxy evolution involves the role of nature (self-regulation) vs. nurture (environment) on the observed properties (and evolution) of galaxies. A collaboration centreed at the Instituto de Astrofisica de Andalucia (Granada, Spain) is trying to address this question by producing a observational database for a sample of 1050 isolated galaxies from the catalogue of Karachentseva (1973) with the overarching goal being the generation of a "zero-point" sample against which effects of environment on galaxies can be assessed. The AMIGA (Analysis of the Interstellar Medium of Isolated Galaxies) database (see www.iaa.es/AMIGA.html) will include optical, IR and radio line and continuum measures. The galaxies in the sample represent the most isolated galaxies in the local universe. In the present contribution, we will present the project, as well as the results of an analysis of the far-infrared (FIR) and molecular gas properties of this sample.

The SAMI Galaxy Survey: Early Data Release

NASA Astrophysics Data System (ADS)

Allen, J. T.; Croom, S. M.; Konstantopoulos, I. S.; Bryant, J. J.; Sharp, R.; Cecil, G. N.; Fogarty, L. M. R.; Foster, C.; Green, A. W.; Ho, I.-T.; Owers, M. S.; Schaefer, A. L.; Scott, N.; Bauer, A. E.; Baldry, I.; Barnes, L. A.; Bland-Hawthorn, J.; Bloom, J. V.; Brough, S.; Colless, M.; Cortese, L.; Couch, W. J.; Drinkwater, M. J.; Driver, S. P.; Goodwin, M.; Gunawardhana, M. L. P.; Hampton, E. J.; Hopkins, A. M.; Kewley, L. J.; Lawrence, J. S.; Leon-Saval, S. G.; Liske, J.; López-Sánchez, Á. R.; Lorente, N. P. F.; McElroy, R.; Medling, A. M.; Mould, J.; Norberg, P.; Parker, Q. A.; Power, C.; Pracy, M. B.; Richards, S. N.; Robotham, A. S. G.; Sweet, S. M.; Taylor, E. N.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

2015-01-01

We present the Early Data Release of the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. The SAMI Galaxy Survey is an ongoing integral field spectroscopic survey of ˜3400 low-redshift (z < 0.12) galaxies, covering galaxies in the field and in groups within the Galaxy And Mass Assembly (GAMA) survey regions, and a sample of galaxies in clusters. In the Early Data Release, we publicly release the fully calibrated data cubes for a representative selection of 107 galaxies drawn from the GAMA regions, along with information about these galaxies from the GAMA catalogues. All data cubes for the Early Data Release galaxies can be downloaded individually or as a set from the SAMI Galaxy Survey website. In this paper we also assess the quality of the pipeline used to reduce the SAMI data, giving metrics that quantify its performance at all stages in processing the raw data into calibrated data cubes. The pipeline gives excellent results throughout, with typical sky subtraction residuals in the continuum of 0.9-1.2 per cent, a relative flux calibration uncertainty of 4.1 per cent (systematic) plus 4.3 per cent (statistical), and atmospheric dispersion removed with an accuracy of 0.09 arcsec, less than a fifth of a spaxel.

Where are compact groups in the local Universe?

NASA Astrophysics Data System (ADS)

Díaz-Giménez, Eugenia; Zandivarez, Ariel

2015-06-01

Aims: The purpose of this work is to perform a statistical analysis of the location of compact groups in the Universe from observational and semi-analytical points of view. Methods: We used the velocity-filtered compact group sample extracted from the Two Micron All Sky Survey for our analysis. We also used a new sample of galaxy groups identified in the 2M++ galaxy redshift catalogue as tracers of the large-scale structure. We defined a procedure to search in redshift space for compact groups that can be considered embedded in other overdense systems and applied this criterion to several possible combinations of different compact and galaxy group subsamples. We also performed similar analyses for simulated compact and galaxy groups identified in a 2M++ mock galaxy catalogue constructed from the Millennium Run Simulation I plus a semi-analytical model of galaxy formation. Results: We observed that only ~27% of the compact groups can be considered to be embedded in larger overdense systems, that is, most of the compact groups are more likely to be isolated systems. The embedded compact groups show statistically smaller sizes and brighter surface brightnesses than non-embedded systems. No evidence was found that embedded compact groups are more likely to inhabit galaxy groups with a given virial mass or with a particular dynamical state. We found very similar results when the analysis was performed using mock compact and galaxy groups. Based on the semi-analytical studies, we predict that 70% of the embedded compact groups probably are 3D physically dense systems. Finally, real space information allowed us to reveal the bimodal behaviour of the distribution of 3D minimum distances between compact and galaxy groups. Conclusions: The location of compact groups should be carefully taken into account when comparing properties of galaxies in environments that are a priori different. Appendices are available in electronic form at http://www.aanda.orgFull Tables B.1 and B.2

VizieR Online Data Catalog: Isolated galaxies, pairs and triplets (Argudo-Fernandez+, 2015)

NASA Astrophysics Data System (ADS)

Argudo-Fernandez, M.; Verley, S.; Bergond, G.; Duarte Puertas, S.; Ramos Carmona, E.; Sabater, J.; Fernandez, Lorenzo M.; Espada, D.; Sulentic, J.; Ruiz, J. E.; Leon, S.

2015-04-01

Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe with positions, redshifts, and degrees of relation with their physical and large-scale environments. (5 data files).

VizieR Online Data Catalog: Ultraviolet Excess Galaxies (Mitchell+ 1982)

NASA Astrophysics Data System (ADS)

Mitchell, K. J.; Brotzman, L. E.; Warnock, A.; Usher, P. D.

2015-05-01

The catalog contains a list of 412 faint galaxies selected for their apparent ultraviolet excess. The galaxies were selected from a 3-color (UBV) plate taken with the Palomar 48-inch Schmidt telescope. The 14-inch-square plates cover an area of 30 square degrees centered on Kapteyn Selected Area 28. The catalog includes running numbers, coordinates, color codes, magnitude codes, morphologies, diameters, and notes. The catalogued galaxies were selected by eye from the Palomar Schmidt 3-color (UBV) plate PS24771, centered on Kapteyn Selexted Area 28 and taken by Usher under conditions of good seeing and transparency. (1 data file).

Planck 2015 results. XXVII. The second Planck catalogue of Sunyaev-Zeldovich sources

NASA Astrophysics Data System (ADS)

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Barrena, R.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Battye, R.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bikmaev, I.; Böhringer, H.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bucher, M.; Burenin, R.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Carvalho, P.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Chon, G.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Comis, B.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Dahle, H.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Eisenhardt, P. R. M.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fergusson, J.; Feroz, F.; Ferragamo, A.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Grainge, K. J. B.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Hempel, A.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jin, T.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Khamitov, I.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mak, D. S. Y.; Mandolesi, N.; Mangilli, A.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; McGehee, P.; Mei, S.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nastasi, A.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Olamaie, M.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrott, Y. C.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rozo, E.; Rubiño-Martín, J. A.; Rumsey, C.; Rusholme, B.; Rykoff, E. S.; Sandri, M.; Santos, D.; Saunders, R. D. E.; Savelainen, M.; Savini, G.; Schammel, M. P.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Shimwell, T. W.; Spencer, L. D.; Stanford, S. A.; Stern, D.; Stolyarov, V.; Stompor, R.; Streblyanska, A.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tramonte, D.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, S. D. M.; Wright, E. L.; Yvon, D.; Zacchei, A.; Zonca, A.

2016-09-01

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky surveyof galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the estimates of the SZ strength parameter Y5R500are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.

The Arecibo Galaxy Environment Survey - VII. A dense filament with extremely long H I streams

NASA Astrophysics Data System (ADS)

Taylor, R.; Minchin, R. F.; Herbst, H.; Davies, J. I.; Rodriguez, R.; Vazquez, C.

2014-09-01

We present completed observations of the NGC 7448 galaxy group and background volume as part of the blind neutral hydrogen Arecibo Galaxy Environment Survey. Our observations cover a region spanning 5°× 4°, over a redshift range of approximately -2000 galaxy density is extremely high (15 deg-2) and many (˜24 per cent) show signs of extended H I emission, including some features as much as 800 kpc in projected length. We describe the overall characteristics of this environment: kinematics, typical galaxy colours and mass-to-light ratios, and substructure. To aid in the cataloguing of this data set, we present a new FITS viewer (FRELLED: FITS Realtime Explorer of Low Latency in Every Dimension). This incorporates interactive source cataloguing tools which increase our source extraction speed by approximately a factor of 50.

Galaxy And Mass Assembly (GAMA): the connection between metals, specific SFR and H I gas in galaxies: the Z-SSFR relation

NASA Astrophysics Data System (ADS)

Lara-López, M. A.; Hopkins, A. M.; López-Sánchez, A. R.; Brough, S.; Colless, M.; Bland-Hawthorn, J.; Driver, S.; Foster, C.; Liske, J.; Loveday, J.; Robotham, A. S. G.; Sharp, R. G.; Steele, O.; Taylor, E. N.

2013-06-01

We study the interplay between gas phase metallicity (Z), specific star formation rate (SSFR) and neutral hydrogen gas (H I) for galaxies of different stellar masses. Our study uses spectroscopic data from Galaxy and Mass Assembly and Sloan Digital Sky Survey (SDSS) star-forming galaxies, as well as H I detection from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) and Galex Arecibo SDSS Survey (GASS) public catalogues. We present a model based on the Z-SSFR relation that shows that at a given stellar mass, depending on the amount of gas, galaxies will follow opposite behaviours. Low-mass galaxies with a large amount of gas will show high SSFR and low metallicities, while low-mass galaxies with small amounts of gas will show lower SSFR and high metallicities. In contrast, massive galaxies with a large amount of gas will show moderate SSFR and high metallicities, while massive galaxies with small amounts of gas will show low SSFR and low metallicities. Using ALFALFA and GASS counterparts, we find that the amount of gas is related to those drastic differences in Z and SSFR for galaxies of a similar stellar mass.

The ASTRODEEP Frontier Fields catalogues. II. Photometric redshifts and rest frame properties in Abell-2744 and MACS-J0416

NASA Astrophysics Data System (ADS)

Castellano, M.; Amorín, R.; Merlin, E.; Fontana, A.; McLure, R. J.; Mármol-Queraltó, E.; Mortlock, A.; Parsa, S.; Dunlop, J. S.; Elbaz, D.; Balestra, I.; Boucaud, A.; Bourne, N.; Boutsia, K.; Brammer, G.; Bruce, V. A.; Buitrago, F.; Capak, P.; Cappelluti, N.; Ciesla, L.; Comastri, A.; Cullen, F.; Derriere, S.; Faber, S. M.; Giallongo, E.; Grazian, A.; Grillo, C.; Mercurio, A.; Michałowski, M. J.; Nonino, M.; Paris, D.; Pentericci, L.; Pilo, S.; Rosati, P.; Santini, P.; Schreiber, C.; Shu, X.; Wang, T.

2016-05-01

Aims: We present the first public release of photometric redshifts, galaxy rest frame properties and associated magnification values in the cluster and parallel pointings of the first two Frontier Fields, Abell-2744 and MACS-J0416. The released catalogues aim to provide a reference for future investigations of extragalactic populations in these legacy fields: from lensed high-redshift galaxies to cluster members themselves. Methods: We exploit a multiwavelength catalogue, ranging from Hubble Space Telescope (HST) to ground-based K and Spitzer IRAC, which is specifically designed to enable detection and measurement of accurate fluxes in crowded cluster regions. The multiband information is used to derive photometric redshifts and physical properties of sources detected either in the H-band image alone, or from a stack of four WFC3 bands. To minimize systematics, median photometric redshifts are assembled from six different approaches to photo-z estimates. Their reliability is assessed through a comparison with available spectroscopic samples. State-of-the-art lensing models are used to derive magnification values on an object-by-object basis by taking into account sources positions and redshifts. Results: We show that photometric redshifts reach a remarkable ~3-5% accuracy. After accounting for magnification, the H-band number counts are found to be in agreement at bright magnitudes with number counts from the CANDELS fields, while extending the presently available samples to galaxies that, intrinsically, are as faint as H ~ 32-33, thanks to strong gravitational lensing. The Frontier Fields allow the galaxy stellar mass distribution to be probed, depending on magnification, at 0.5-1.5 dex lower masses with respect to extragalactic wide fields, including sources at Mstar ~ 107-108 M⊙ at z > 5. Similarly, they allow the detection of objects with intrinsic star formation rates (SFRs) >1 dex lower than in the CANDELS fields reaching 0.1-1 M⊙/yr at z ~ 6-10. The

ICE-COLA: fast simulations for weak lensing observables

NASA Astrophysics Data System (ADS)

Izard, Albert; Fosalba, Pablo; Crocce, Martin

2018-01-01

Approximate methods to full N-body simulations provide a fast and accurate solution to the development of mock catalogues for the modelling of galaxy clustering observables. In this paper we extend ICE-COLA, based on an optimized implementation of the approximate COLA method, to produce weak lensing maps and halo catalogues in the light-cone using an integrated and self-consistent approach. We show that despite the approximate dynamics, the catalogues thus produced enable an accurate modelling of weak lensing observables one decade beyond the characteristic scale where the growth becomes non-linear. In particular, we compare ICE-COLA to the MICE Grand Challenge N-body simulation for some fiducial cases representative of upcoming surveys and find that, for sources at redshift z = 1, their convergence power spectra agree to within 1 per cent up to high multipoles (i.e. of order 1000). The corresponding shear two point functions, ξ+ and ξ-, yield similar accuracy down to 2 and 20 arcmin respectively, while tangential shear around a z = 0.5 lens sample is accurate down to 4 arcmin. We show that such accuracy is stable against an increased angular resolution of the weak lensing maps. Hence, this opens the possibility of using approximate methods for the joint modelling of galaxy clustering and weak lensing observables and their covariance in ongoing and future galaxy surveys.

Documentation for the machine-readable version of the Uppsala general catalogue of galaxies

NASA Technical Reports Server (NTRS)

Warren, W. H., Jr.

1982-01-01

The machine-readable version of the catalog containing descriptions of galaxies, their surrounding areas, and position angles for flattened galaxies is described. In addition to the correction of several errors discovered in a previous computerized version, a few duplicate records were removed and the record structure was revised slightly to accommodate a large data value and to remove superfluous blanks.

Optical-to-virial velocity ratios of local disc galaxies from combined kinematics and galaxy-galaxy lensing

NASA Astrophysics Data System (ADS)

Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Nakajima, R.; Seljak, U.; Hirata, C. M.

2012-10-01

In this paper, we measure the optical-to-virial velocity ratios Vopt/V200c of disc galaxies in the Sloan Digital Sky Survey (SDSS) at a mean redshift of = 0.07 and with stellar masses 109 < M* < 1011 M⊙. Vopt/V200c, the ratio of the circular velocity measured at the optical radius of the disc (˜10 kpc) to that at the virial radius of the dark matter halo (˜150 kpc), is a powerful observational constraint on disc galaxy formation. It links galaxies to their dark matter haloes dynamically and constrains the total mass profile of disc galaxies over an order of magnitude in length scale. For this measurement, we combine Vopt derived from the Tully-Fisher relation (TFR) from Reyes et al. with V200c derived from halo masses measured with galaxy-galaxy lensing. In anticipation of this combination, we use similarly selected galaxy samples for both the TFR and lensing analysis. For three M* bins with lensing-weighted mean stellar masses of 0.6, 2.7 and 6.5 × 1010 M⊙, we find halo-to-stellar mass ratios M200c/M* = 41, 23 and 26, with 1σ statistical uncertainties of around 0.1 dex, and Vopt/V200c = 1.27 ± 0.08, 1.39 ± 0.06 and 1.27 ± 0.08 (1σ), respectively. Our results suggest that the dark matter and baryonic contributions to the mass within the optical radius are comparable, if the dark matter halo profile has not been significantly modified by baryons. The results obtained in this work will serve as inputs to and constraints on disc galaxy formation models, which will be explored in future work. Finally, we note that this paper presents a new and improved galaxy shape catalogue for weak lensing that covers the full SDSS Data Release 7 footprint.

Hipparcos to deliver its final results catalogue soon

NASA Astrophysics Data System (ADS)

1995-10-01

them, almost 30 years ago, to propose carrying out these observations from the relatively benign environment of space. Hipparcos is, by present standards, a medium-sized satellite, with a 30 cm telescope sensing simply ordinary light. But it has been described as the most imaginative in the short history of space astronomy. This foresight has been amply repaid. In the long history of stargazing it ranks with the surveys by Hipparchus the Greek in the 2nd Century BC and by Tichy Brahe the Dane in the 16th Century AD, both of which transformed human perceptions of the Universe. Positions derived from the Hipparcos satellite are better than a millionth of a degree, and newly a thousand times more accurate than star positions routinely determined from he ground. This accuracy makes it possible to measure directly the distances to the stars. While it took 250 years between astronomers first setting out on the exacting task of measuring the distance to a star, and a stellar distance being measured for the first time, ESA's Hipparcos mission has revolutionised this long, painstaking, and fundamental task by measuring accurate distances and movements of more than one hundred thousand. The measurement concept involved he satellite triangulating its way between he stars all wound the sky, building up a celestial map in much the same way as land surveyors use triangulation between hill-tops to measure distances accurately. Only the angles involved are much smaller : the accuracy that has been achieved with the Hipparcos Catalogue is such that he two edges of a coin, viewed from he other side of the Atlantic Ocean, could be distinguished. The results from Hipparcos will deliver scientists with long-awaited details of our place in he Milky Way Galaxy. Most of he stars visible to the naked eye are, to a large extent, companions of the Sun, in a great orbital march around the centre of the Galaxy, a journey so long that it takes individual stars 250 million years to complete, in

Técnica de Construcción de Catálogos Sintéticos

NASA Astrophysics Data System (ADS)

Díaz, M. E.; Muriel, H.; Merchán, M.

We present a mock catalogue construction technic which enable us to mimic simultaniously several observational properties, such as spectral types, angular positions, redshifts distribution, aparent and absolut magnitudes and gravitational evolution. We analyze some prescriptions for volume and flux limited samples. As an aplication, we present a mock catalogue of the 2dF redshift survey and the corresponding comparison between the observational properties of the real data and the corresponding to the mock catalogue constructed in this work.

SDSS-IV MaNGA: the spectroscopic discovery of strongly lensed galaxies

NASA Astrophysics Data System (ADS)

Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

2018-06-01

We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for eight of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with two background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise ratio background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7 arcsec, which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

Cross-correlation of the X-ray background with nearby galaxies

NASA Technical Reports Server (NTRS)

Jahoda, Keith; Mushotzky, Richard F.; Boldt, Elihu; Lahav, Ofer

1991-01-01

The detection of a signal in the cross-correlation of the diffuse 2-10 keV HEAO 1 A-2 X-ray surface brightness with the galaxy surface density derived from diameter-limited samples from the Uppsala General Catalogue is reported. An ad hoc relationship between the X-ray flux and the galaxy counts is used to estimate the local X-ray volume emissivity at 2.8 + or - 1.0 x 10 to the 38th ergs/s/cu Mpc. This result implies that unevolved populations of X-ray sources correlated with present-epoch galaxies can contribute only 13 + or - 5 percent of the cosmic X-ray background.

Study of the Lynx-Cancer void galaxies. - V. The extremely isolated galaxy UGC 4722

NASA Astrophysics Data System (ADS)

Chengalur, J. N.; Pustilnik, S. A.; Makarov, D. I.; Perepelitsyna, Y. A.; Safonova, E. S.; Karachentsev, I. D.

2015-04-01

We present a detailed study of the extremely isolated Sdm galaxy UGC 4722 (MB = -17.4) located in the nearby Lynx-Cancer void. UGC 4722 is a member of the Catalogue of Isolated Galaxies, and has also been identified as one of the most isolated galaxies in the Local Supercluster. Optical images of the galaxy however show that it has a peculiar morphology with an elongated ˜14 kpc-long plume. New observations with the Russian 6-m telescope (BTA) and the Giant Metrewave Radio Telescope (GMRT) of the ionized and neutral gas in UGC 4722 reveal the second component responsible for the disturbed morphology of the system. This is a small, almost completely destroyed, very gas-rich dwarf (MB = -15.2, M(H I)/LB ˜ 4.3) We estimate the oxygen abundance for both galaxies to be 12 + log (O/H) ˜ 7.5-7.6 which is two to three times lower than what is expected from the luminosity-metallicity relation for similar galaxies in denser environments. The ugr colours of the plume derived from Sloan Digital Sky Survey (SDSS) images are consistent with a simple stellar population with a post starburst age of 0.45-0.5 Gyr. This system hence appears to be the first known case of a minor merger with a prominent tidal feature consisting of a young stellar population.

Planck 2015 results: XXVII. The second Planck catalogue of Sunyaev-Zeldovich sources

DOE PAGES

Ade, P. A. R.; Aghanim, N.; Arnaud, M.; ...

2016-09-20

Here, we present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky surveyof galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that themore » estimates of the SZ strength parameter Y5R500are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.« less

Users and Union Catalogues

ERIC Educational Resources Information Center

Hartley, R. J.; Booth, Helen

2006-01-01

Union catalogues have had an important place in libraries for many years. Their use has been little investigated. Recent interest in the relative merits of physical and virtual union catalogues and a recent collaborative project between a physical and several virtual union catalogues in the United Kingdom led to the opportunity to study how users…

VizieR Online Data Catalog: The XMM-Newton 2nd Incremental Source Catalogue (2XMMi) (XMM-SSC, 2008)

NASA Astrophysics Data System (ADS)

Xmm-Newton Survey Science Centre, Consortium

2007-09-01

The 2XMMi catalogue is the fourth publicly released XMM X-ray source catalogue produced by the XMM Survey Science Centre (SSC) consortium, following the 1XMM (Cat. IX/37, released in April 2003), 2XMMp (July 2006) and 2XMM (Cat. IX/39, August 2007) catalogues: 2XMMp was a preliminary version of 2XMM. 2XMMi is an incremental version of the 2XMM catalogue. The 2XMMi catalogue is about 17% larger than the 2XMM catalogue, which it supersedes, due to the 1-year longer baseline of observations included (it is about 8 times larger than the 1XMM catalogue). As such, it is the largest X-ray source catalogue ever produced, containing more than twice as many discrete sources as either the ROSAT survey or pointed catalogues. 2XMMi complements deeper Chandra and XMM-Newton small area surveys, probing a large sky area at the flux limit where the bulk of the objects that contribute to the X-ray background lie. The 2XMMi catalogue provides a rich resource for generating large, well-defined samples for specific studies, utilizing the fact that X-ray selection is a highly efficient (arguably the most efficient) way of selecting certain types of object, notably active galaxies (AGN), clusters of galaxies, interacting compact binaries and active stellar coronae. The large sky area covered by the serendipitous survey, or equivalently the large size of the catalogue, also means that 2XMMi is a superb resource for exploring the variety of the X-ray source population and identifying rare source types. The production of the 2XMMi catalogue has been undertaken by the XMM-Newton SSC consortium in fulfilment of one of its major responsibilities within the XMM-Newton project. The catalogue production process has been designed to exploit fully the capabilities of the XMM-Newton EPIC cameras and to ensure the integrity and quality of the resultant catalogue through rigorous screening of the data. The predecessor 2XMM catalogue was made from a subset of public observations emerging from a re

VizieR Online Data Catalog: The XMM-Newton 2nd Incremental Source Catalogue (2XMMi) (XMM-SSC, 2008)

NASA Astrophysics Data System (ADS)

Xmm-Newton Survey Science Centre, Consortium

2008-09-01

The 2XMMi catalogue is the fourth publicly released XMM X-ray source catalogue produced by the XMM Survey Science Centre (SSC) consortium, following the 1XMM (Cat. IX/37, released in April 2003), 2XMMp (July 2006) and 2XMM (Cat. IX/39, August 2007) catalogues: 2XMMp was a preliminary version of 2XMM. 2XMMi is an incremental version of the 2XMM catalogue. The 2XMMi catalogue is about 17% larger than the 2XMM catalogue, which it supersedes, due to the 1-year longer baseline of observations included (it is about 8 times larger than the 1XMM catalogue). As such, it is the largest X-ray source catalogue ever produced, containing more than twice as many discrete sources as either the ROSAT survey or pointed catalogues. 2XMMi complements deeper Chandra and XMM-Newton small area surveys, probing a large sky area at the flux limit where the bulk of the objects that contribute to the X-ray background lie. The 2XMMi catalogue provides a rich resource for generating large, well-defined samples for specific studies, utilizing the fact that X-ray selection is a highly efficient (arguably the most efficient) way of selecting certain types of object, notably active galaxies (AGN), clusters of galaxies, interacting compact binaries and active stellar coronae. The large sky area covered by the serendipitous survey, or equivalently the large size of the catalogue, also means that 2XMMi is a superb resource for exploring the variety of the X-ray source population and identifying rare source types. The production of the 2XMMi catalogue has been undertaken by the XMM-Newton SSC consortium in fulfilment of one of its major responsibilities within the XMM-Newton project. The catalogue production process has been designed to exploit fully the capabilities of the XMM-Newton EPIC cameras and to ensure the integrity and quality of the resultant catalogue through rigorous screening of the data. The predecessor 2XMM catalogue was made from a subset of public observations emerging from a re

Chemical evolution of Local Group dwarf galaxies in a cosmological context - I. A new modelling approach and its application to the Sculptor dwarf spheroidal galaxy

NASA Astrophysics Data System (ADS)

Romano, Donatella; Starkenburg, Else

2013-09-01

We present a new approach for chemical evolution modelling, specifically designed to investigate the chemical properties of dwarf galaxies in a full cosmological framework. In particular, we focus on the Sculptor dwarf spheroidal galaxy, for which a wealth of observational data exists, as a test bed for our model. We select four candidate Sculptor-like galaxies from the satellite galaxy catalogue generated by implementation of a version of the Munich semi-analytic model for galaxy formation on the level 2 Aquarius dark matter simulations and use the mass assembly and star formation histories predicted for these four systems as an input for the chemical evolution code. We follow explicitly the evolution of several chemical elements, both in the cold gas out of which the stars form and in the hot medium residing in the halo. We take into account in detail the lifetimes of stars of different initial masses, the distribution of the delay times for Type Ia supernova explosions and the dependence of the stellar yields from the initial metallicity of the stars. We allow large fractions of metals to be deposited into the hot phase, either directly as stars die or through reheated gas flows powered by supernova explosions. We find that, in order to reproduce both the observed metallicity distribution function and the observed abundance ratios of long-lived stars of Sculptor, large fractions of the reheated metals must never re-enter regions of active star formation. With this prescription, all the four analogues to the Sculptor dwarf spheroidal galaxy extracted from the simulated satellites catalogue on the basis of luminosity and stellar population ages are found to reasonably match the detailed chemical properties of real Sculptor stars. However, all model galaxies do severely underestimate the fraction of very metal poor stars observed in Sculptor. Our analysis thus sets further constraints on the semi-analytical models and, at large, on possible metal enrichment

Galaxy-galaxy lensing in EAGLE: comparison with data from 180 deg2 of the KiDS and GAMA surveys

NASA Astrophysics Data System (ADS)

Velliscig, Marco; Cacciato, Marcello; Hoekstra, Henk; Schaye, Joop; Heymans, Catherine; Hildebrandt, Hendrik; Loveday, Jon; Norberg, Peder; Sifón, Cristóbal; Schneider, Peter; van Uitert, Edo; Viola, Massimo; Brough, Sarah; Erben, Thomas; Holwerda, Benne W.; Hopkins, Andrew M.; Kuijken, Konrad

2017-11-01

We present predictions for the galaxy-galaxy lensing (GGL) profile from the EAGLE hydrodynamical cosmological simulation at redshift z = 0.18, in the spatial range 0.02 < R/(h- 1 Mpc) < 2, and for five logarithmically equispaced stellar mass bins in the range 10.3 < log10(Mstar/ M⊙) < 11.8. We compare these excess surface density profiles to the observed signal from background galaxies imaged by the Kilo Degree Survey around spectroscopically confirmed foreground galaxies from the Galaxy And Mass Assembly (GAMA) survey. Exploiting the GAMA galaxy group catalogue, the profiles of central and satellite galaxies are computed separately for groups with at least five members to minimize contamination. EAGLE predictions are in broad agreement with the observed profiles for both central and satellite galaxies, although the signal is underestimated at R ≈ 0.5-2 h- 1 Mpc for the highest stellar mass bins. When central and satellite galaxies are considered simultaneously, agreement is found only when the selection function of lens galaxies is taken into account in detail. Specifically, in the case of GAMA galaxies, it is crucial to account for the variation of the fraction of satellite galaxies in bins of stellar mass induced by the flux-limited nature of the survey. We report the inferred stellar-to-halo mass relation and we find good agreement with recent published results. We note how the precision of the GGL profiles in the simulation holds the potential to constrain fine-grained aspects of the galaxy-dark matter connection.

Multiwavelength mock observations of the WHIM in a simulated galaxy cluster

NASA Astrophysics Data System (ADS)

Planelles, Susana; Mimica, Petar; Quilis, Vicent; Cuesta-Martínez, Carlos

2018-06-01

About half of the expected total baryon budget in the local Universe is `missing'. Hydrodynamical simulations suggest that most of the missing baryons are located in a mildly overdense, warm-hot intergalactic medium (WHIM), which is difficult to be detected at most wavelengths. In this paper, we explore multiwavelength synthetic observations of a massive galaxy cluster developed in a full Eulerian-adaptive mesh refinement cosmological simulation. A novel numerical procedure is applied on the outputs of the simulation, which are post-processed with a full-radiative transfer code that can compute the change of the intensity at any frequency along the null geodesic of photons. We compare the emission from the whole intergalactic medium and from the WHIM component (defined as the gas with a temperature in the range 105-107 K) at three observational bands associated with thermal X-rays, thermal and kinematic Sunyaev-Zel'dovich effect, and radio emission. The synthetic maps produced by this procedure could be directly compared with existing observational maps and could be used as a guide for future observations with forthcoming instruments. The analysis of the different emissions associated with a high-resolution galaxy cluster is in broad agreement with previous simulated and observational estimates of both gas components.

Galaxy and Mass Assembly (GAMA): halo formation times and halo assembly bias on the cosmic web

NASA Astrophysics Data System (ADS)

Tojeiro, Rita; Eardley, Elizabeth; Peacock, John A.; Norberg, Peder; Alpaslan, Mehmet; Driver, Simon P.; Henriques, Bruno; Hopkins, Andrew M.; Kafle, Prajwal R.; Robotham, Aaron S. G.; Thomas, Peter; Tonini, Chiara; Wild, Vivienne

2017-09-01

We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.

THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy

NASA Astrophysics Data System (ADS)

Ramos-Medina, J.; Sánchez Contreras, C.; García-Lario, P.; Rodrigo, C.; da Silva Santos, J.; Solano, E.

2018-03-01

This is the first of a series of papers presenting the THROES (A caTalogue of HeRschel Observations of Evolved Stars) project, intended to provide a comprehensive overview of the spectroscopic results obtained in the far-infrared (55-670 μm) with the Herschel space observatory on low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the catalogue of interactively reprocessed Photoconductor Array Camera and Spectrometer (PACS) spectra covering the 55-200 μm range for 114 stars in this category for which PACS range spectroscopic data is available in the Herschel Science Archive (HSA). Our sample includes objects spanning a range of evolutionary stages, from the asymptotic giant branch to the planetary nebula phase, displaying a wide variety of chemical and physical properties. The THROES/PACS catalogue is accessible via a dedicated web-based interface and includes not only the science-ready Herschel spectroscopic data for each source, but also complementary photometric and spectroscopic data from other infrared observatories, namely IRAS, ISO, or AKARI, at overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset that can be used by the scientific community in the future to deepen our knowledge and understanding of these latest stages of the evolution of low-to-intermediate mass stars. The THROES/PACS catalogue is accessible at http://https://throes.cab.inta-csic.es/

The AMIGA sample of isolated galaxies. XIII. The HI content of an almost "nurture free" sample

NASA Astrophysics Data System (ADS)

Jones, M. G.; Espada, D.; Verdes-Montenegro, L.; Huchtmeier, W. K.; Lisenfeld, U.; Leon, S.; Sulentic, J.; Sabater, J.; Jones, D. E.; Sanchez, S.; Garrido, J.

2018-01-01

Context. We present the largest catalogue of HI single dish observations of isolated galaxies to date, as part of the multi-wavelength compilation being performed by the AMIGA project (Analysis of the interstellar Medium in Isolated GAlaxies). Despite numerous studies of the HI content of galaxies, no revision focused on the HI scaling relations of the most isolated L∗ galaxies has been made since Haynes & Giovanelli (1984, AJ, 89, 758). Aims: The AMIGA sample has been demonstrated to be almost "nurture free", therefore, by creating scaling relations for the HI content of these galaxies we will define a metric of HI normalcy in the absence of interactions. Methods: The catalogue comprises of our own HI observations with Arecibo, Effelsberg, Nançay and GBT, and spectra collected from the literature. In total we have measurements or constraints on the HI masses of 844 galaxies from the Catalogue of Isolated Galaxies (CIG). The multi-wavelength AMIGA dataset includes a revision of the B-band luminosities (LB), optical diameters (D25), morphologies, and isolation. Due to the large size of the catalogue, these revisions permit cuts to be made to ensure isolation and a high level of completeness, which was not previously possible. With this refined dataset we fit HI scaling relations based on luminosity, optical diameter and morphology. Our regression model incorporates all the data, including upper limits, and accounts for uncertainties in both variables, as well as distance uncertainties. Results: The scaling relation of HI mass with D25 is in good agreement with that of Haynes & Giovanelli (1984), but our relation with LB is considerably steeper. This disagreement is attributed to the large uncertainties in the luminosities, which introduce a bias when fitting with ordinary least squares regression (as was done in previous works), and the different morphology distributions of the samples. We find that the main effect of morphology on the D25-relation is to increase

Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, C.; Pujol, A.; Gaztañaga, E.

We measure the redshift evolution of galaxy bias from a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for amore » $$\\sim$$116 deg$$^{2}$$ area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al., in prep) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a magnitude-limited galaxy sample. We find the galaxy bias and 1$$\\sigma$$ error bars in 4 photometric redshift bins to be 1.33$$\\pm$$0.18 (z=0.2-0.4), 1.19$$\\pm$$0.23 (z=0.4-0.6), 0.99$$\\pm$$0.36 ( z=0.6-0.8), and 1.66$$\\pm$$0.56 (z=0.8-1.0). These measurements are consistent at the 1-2$$\\sigma$$ level with mea- surements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing. In addition, our method provides the only $$\\sigma_8$$-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.« less

LOFAR-Boötes: properties of high- and low-excitation radio galaxies at 0.5 < z < 2.0

NASA Astrophysics Data System (ADS)

Williams, W. L.; Calistro Rivera, G.; Best, P. N.; Hardcastle, M. J.; Röttgering, H. J. A.; Duncan, K. J.; de Gasperin, F.; Jarvis, M. J.; Miley, G. K.; Mahony, E. K.; Morabito, L. K.; Nisbet, D. M.; Prandoni, I.; Smith, D. J. B.; Tasse, C.; White, G. J.

2018-04-01

This paper presents a study of the redshift evolution of radio-loud active galactic nuclei (AGN) as a function of the properties of their galaxy hosts in the Boötes field. To achieve this we match low-frequency radio sources from deep 150-MHz LOFAR (LOw Frequency ARray) observations to an I-band-selected catalogue of galaxies, for which we have derived photometric redshifts, stellar masses, and rest-frame colours. We present spectral energy distribution (SED) fitting to determine the mid-infrared AGN contribution for the radio sources and use this information to classify them as high- versus low-excitation radio galaxies (HERGs and LERGs) or star-forming galaxies. Based on these classifications, we construct luminosity functions for the separate redshift ranges going out to z = 2. From the matched radio-optical catalogues, we select a sub-sample of 624 high power (P150 MHz > 1025 W Hz-1) radio sources between 0.5 ≤ z < 2. For this sample, we study the fraction of galaxies hosting HERGs and LERGs as a function of stellar mass and host galaxy colour. The fraction of HERGs increases with redshift, as does the fraction of sources in galaxies with lower stellar masses. We find that the fraction of galaxies that host LERGs is a strong function of stellar mass as it is in the local Universe. This, combined with the strong negative evolution of the LERG luminosity functions over this redshift range, is consistent with LERGs being fuelled by hot gas in quiescent galaxies.

Galaxy populations in the Antlia cluster - III. Properties of faint early-type galaxies

NASA Astrophysics Data System (ADS)

Smith Castelli, Analía. V.; Cellone, Sergio A.; Faifer, Favio R.; Bassino, Lilia P.; Richtler, Tom; Romero, Gisela A.; Calderón, Juan Pablo; Caso, Juan Pablo

2012-01-01

We present a new analysis of the early-type galaxy population in the central region of the Antlia cluster, focusing on the faint systems such as dwarf ellipticals (dEs) and dwarf spheroidals (dSphs). The colour-magnitude relation (CMR) and the relation between luminosity and mean effective surface brightness for galaxies in the central region of Antlia have been previously studied in Paper I of the present series. Now we confirm 22 early-type galaxies as Antlia members, using Gemini-GMOS and Magellan-MIKE spectra. Among them, 15 are dEs from the FS90 Antlia Group catalogue, two belong to the rare type of compact ellipticals (cEs) and five are new faint dwarfs that had never been catalogued before. In addition, we present 16 newly identified low-surface-brightness galaxy candidates, almost half of them displaying morphologies consistent with being Antlia's counterparts of Local Group dSphs, which extend the faint luminosity limit of our study down to MB=-10.1(BT= 22.6) mag. With these new data, we built an improved CMR in the Washington photometric system, i.e. integrated T1 magnitudes versus (C-T1) colours, which extends ˜4 mag faintwards the limit of spectroscopically confirmed Antlia members. When only confirmed early-type members are considered, this relation extends over 10 mag in luminosity with no apparent change in slope or increase in colour dispersion towards its faint end. The intrinsic colour scatter of the relation is compared with those reported for other clusters of galaxies; we argue that it is likely that the large scatter of the CMR, usually reported at faint magnitudes, is mostly due to photometric errors along with an improper membership/morphological classification. The distinct behaviour of the luminosity versus mean effective surface brightness relation at the bright and faint ends is analysed, while it is confirmed that dE galaxies on the same relation present a very similar effective radius, regardless of their colour. The projected spatial

The ASTRODEEP Frontier Fields catalogues. I. Multiwavelength photometry of Abell-2744 and MACS-J0416

NASA Astrophysics Data System (ADS)

Merlin, E.; Amorín, R.; Castellano, M.; Fontana, A.; Buitrago, F.; Dunlop, J. S.; Elbaz, D.; Boucaud, A.; Bourne, N.; Boutsia, K.; Brammer, G.; Bruce, V. A.; Capak, P.; Cappelluti, N.; Ciesla, L.; Comastri, A.; Cullen, F.; Derriere, S.; Faber, S. M.; Ferguson, H. C.; Giallongo, E.; Grazian, A.; Lotz, J.; Michałowski, M. J.; Paris, D.; Pentericci, L.; Pilo, S.; Santini, P.; Schreiber, C.; Shu, X.; Wang, T.

2016-05-01

Context. The Frontier Fields survey is a pioneering observational program aimed at collecting photometric data, both from space (Hubble Space Telescope and Spitzer Space Telescope) and from ground-based facilities (VLT Hawk-I), for six deep fields pointing at clusters of galaxies and six nearby deep parallel fields, in a wide range of passbands. The analysis of these data is a natural outcome of the Astrodeep project, an EU collaboration aimed at developing methods and tools for extragalactic photometry and creating valuable public photometric catalogues. Aims: We produce multiwavelength photometric catalogues (from B to 4.5 μm) for the first two of the Frontier Fields, Abell-2744 and MACS-J0416 (plus their parallel fields). Methods: To detect faint sources even in the central regions of the clusters, we develop a robust and repeatable procedure that uses the public codes Galapagos and Galfit to model and remove most of the light contribution from both the brightest cluster members, and the intra-cluster light. We perform the detection on the processed HST H160 image to obtain a pure H-selected sample, which is the primary catalogue that we publish. We also add a sample of sources which are undetected in the H160 image but appear on a stacked infrared image. Photometry on the other HST bands is obtained using SExtractor, again on processed images after the procedure for foreground light removal. Photometry on the Hawk-I and IRAC bands is obtained using our PSF-matching deconfusion code t-phot. A similar procedure, but without the need for the foreground light removal, is adopted for the Parallel fields. Results: The procedure of foreground light subtraction allows for the detection and the photometric measurements of ~2500 sources per field. We deliver and release complete photometric H-detected catalogues, with the addition of the complementary sample of infrared-detected sources. All objects have multiwavelength coverage including B to H HST bands, plus K

Clusters of Galaxies at High Redshift

NASA Astrophysics Data System (ADS)

Fort, Bernard

For a long time, the small number of clusters at z > 0.3 in the Abell survey catalogue and simulations of the standard CDM formation of large scale structures provided a paradigm where clusters were considered as young merging structures. At earlier times, loose concentrations of galaxy clumps were mostly anticipated. Recent observations broke the taboo. Progressively we became convinced that compact and massive clusters at z = 1 or possibly beyond exist and should be searched for.

The optical properties of galaxies in the Ophiuchus cluster

NASA Astrophysics Data System (ADS)

Durret, F.; Wakamatsu, K.; Adami, C.; Nagayama, T.; Omega Muleka Mwewa Mwaba, J. M.

2018-05-01

Context. Ophiuchus is one of the most massive clusters known, but due to its low Galactic latitude its optical properties remain poorly known. Aims: We investigate the optical properties of Ophiuchus to obtain clues on the formation epoch of this cluster, and compare them to those of the Coma cluster, which is comparable in mass to Ophiuchus but much more dynamically disturbed. Methods: Based on a deep image of the Ophiuchus cluster in the r' band obtained at the Canada France Hawaii Telescope with the MegaCam camera, we have applied an iterative process to subtract the contribution of the numerous stars that, due to the low Galactic latitude of the cluster, pollute the image, and have obtained a photometric catalogue of 2818 galaxies fully complete at r' = 20.5 mag and still 91% complete at r' = 21.5 mag. We use this catalogue to derive the cluster Galaxy Luminosity Function (GLF) for the overall image and for a region (hereafter the "rectangle" region) covering exactly the same physical size as the region in which the GLF of the Coma cluster was previously studied. We then compute density maps based on an adaptive kernel technique, for different magnitude limits, and define three circular regions covering 0.08, 0.08, and 0.06 deg2, respectively, centred on the cluster (C), on northwest (NW) of the cluster, and southeast (SE) of the cluster, in which we compute the GLFs. Results: The GLF fits are much better when a Gaussian is added to the usual Schechter function, to account for the excess of very bright galaxies. Compared to Coma, Ophiuchus shows a strong excess of bright galaxies. Conclusions: The properties of the two nearby very massive clusters Ophiuchus and Coma are quite comparable, though they seem embedded in different large-scale environments. Our interpretation is that Ophiuchus was built up long ago, as confirmed by its relaxed state (see paper I) while Coma is still in the process of forming. The photometric catalogue of Ophiuchus (full Table B.1) is

Aperture Effects in the Long Slit Spectrophotometry of the Polar Ring Galaxy IIZw71

NASA Astrophysics Data System (ADS)

Pérez-Montero, E.; García-Benito, R.; Díaz, Á. I.; Pérez, E.; Kehrig, C.

2008-10-01

Polar ring galaxies are composed by an early type galaxy and a polar ring rotating around it and which is rich in gas, dust and star formation. IIZw71 is catalogued as a blue compact dwarf galaxy and as a probable polar ring galaxy (Whitmore et al. 1990). The formation of the polar ring and the very luminous bursts of star formation along it, is a consequence of the interaction with a close companion, IIZw70, situated at 18.1 kpc (Cox et al. 2001). We have carried out spectrophotometric observations of the bursts of star formation along the polar ring in order to study differences in the physical properties or the star formation histories between the knots

A Catalogue of Massive Young Stellar Objects

NASA Astrophysics Data System (ADS)

Chan, S. J.; Henning, Th.; Schreyer, K.

1994-12-01

We report on an ongoing project to compile a catalogue of massive young stellar objects (YSOs). Massive young stellar objects are compact and luminous infrared sources. The stellar core is still surrounded by optically thick dust shells (cf. Henning 1990, Fundamentals of Cosmic Physics, 14, 321). This catalogue, which contains about 250 objects, will provide comprehensive information such as infrared and radio flux densities, association with maser sources, and outflow phenomena. The objects were selected from the IRAS Point Source Catalogue based on the following criteria: (1) IRAS flux density qualities >= 2 in the 4 IRAS bands (12 microns, 25 microns, 60 microns and 100 microns). (2) Fnu(12microns) <= Fnu(25microns) <= Fnu(60microns) <= F_ν(100microns) Fnu(100microns) >= 1000 Jy (3) IRAS colors (including uncertainty 0.15) should be within the following color box: -0.15 >= R(12/25) >= 1.15, -0.15 >= R(25/60) >= 0.75, -0.35 >= R(60/100) >= 0.35, where R(i/j)=jF_nu (i)/iF_nu (j) (Henning et al. 1990, A&A, 227, 542) (4) IRAS idtype (type of objects)!= 1; objects are not associated with galaxies or late-type stars; ∣b∣ <= 10{(deg}) Our main goal is to collect the observational data of these sources as complete as possible. The flux densities from near-infrared to radio range are assembled (J, H, K bands, IRAS bands, 350 microns, 800 microns and 1.3 mm bands, 2 cm and 6 cm bands). The information on dust features (such as ice, silicate, PAH) comes from the IRAS Low Resolution Spectrometer Atlas and literature (cf. Volk & Cohen, 1989, AJ, 98, 931). The maser sources (H_2O, type I OH, CH_3OH) and NH_3, HCO(+) , and CS molecular line data towards these objects, which have been observed, are also reported. The CO outflow velocity will be given if the object is found to be associated with an outflow.

Signatures of the Primordial Universe from Its Emptiness: Measurement of Baryon Acoustic Oscillations from Minima of the Density Field.

PubMed

Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Liang, Yu; Zhao, Cheng; Tao, Charling; Rodríguez-Torres, Sergio; Eisenstein, Daniel J; Gil-Marín, Héctor; Kneib, Jean-Paul; McBride, Cameron; Percival, Will J; Ross, Ashley J; Sánchez, Ariel G; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Zhao, Gong-Bo

2016-04-29

Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.

Galactic Outflows and Their Correlation with Galaxy Properties at 0.8 < z < 1.6

NASA Astrophysics Data System (ADS)

Whiting, Lindsey M.

Out. ows have been shown to be ubiquitous in galaxies between z = 1 and z=2, and many models and observations have attempted to correlate the absorption line. properties of these out. ows with morphological characteristics of their host galaxies. In this study, we examined the spectra of 71 galaxies with redshifts 1< z<2, paying. particular attention to the FeII and MgII absorption lines. We plotted the equivalent. width, velocity, and maximum velocity of the absorption features against various. physical properties of the galaxies, obtained from catalogues created by Skelton et. al., (2014) and van der Wel et al., (2012). We conrmed the presence of out. ows in. our galaxy sample, and found a signicant trend between the equivalent width and. star formation rate - out. owing gas has stronger absorption lines in galaxies with. higher star formation rates.

CMU DeepLens: deep learning for automatic image-based galaxy-galaxy strong lens finding

NASA Astrophysics Data System (ADS)

Lanusse, François; Ma, Quanbin; Li, Nan; Collett, Thomas E.; Li, Chun-Liang; Ravanbakhsh, Siamak; Mandelbaum, Rachel; Póczos, Barnabás

2018-01-01

Galaxy-scale strong gravitational lensing can not only provide a valuable probe of the dark matter distribution of massive galaxies, but also provide valuable cosmological constraints, either by studying the population of strong lenses or by measuring time delays in lensed quasars. Due to the rarity of galaxy-scale strongly lensed systems, fast and reliable automated lens finding methods will be essential in the era of large surveys such as Large Synoptic Survey Telescope, Euclid and Wide-Field Infrared Survey Telescope. To tackle this challenge, we introduce CMU DeepLens, a new fully automated galaxy-galaxy lens finding method based on deep learning. This supervised machine learning approach does not require any tuning after the training step which only requires realistic image simulations of strongly lensed systems. We train and validate our model on a set of 20 000 LSST-like mock observations including a range of lensed systems of various sizes and signal-to-noise ratios (S/N). We find on our simulated data set that for a rejection rate of non-lenses of 99 per cent, a completeness of 90 per cent can be achieved for lenses with Einstein radii larger than 1.4 arcsec and S/N larger than 20 on individual g-band LSST exposures. Finally, we emphasize the importance of realistically complex simulations for training such machine learning methods by demonstrating that the performance of models of significantly different complexities cannot be distinguished on simpler simulations. We make our code publicly available at https://github.com/McWilliamsCenter/CMUDeepLens.

Galaxy Tagging: photometric redshift refinement and group richness enhancement

NASA Astrophysics Data System (ADS)

Kafle, P. R.; Robotham, A. S. G.; Driver, S. P.; Deeley, S.; Norberg, P.; Drinkwater, M. J.; Davies, L. J.

2018-06-01

We present a new scheme, galtag, for refining the photometric redshift measurements of faint galaxies by probabilistically tagging them to observed galaxy groups constructed from a brighter, magnitude-limited spectroscopy survey. First, this method is tested on the DESI light-cone data constructed on the GALFORM galaxy formation model to tests its validity. We then apply it to the photometric observations of galaxies in the Kilo-Degree Imaging Survey (KiDS) over a 1 deg2 region centred at 15h. This region contains Galaxy and Mass Assembly (GAMA) deep spectroscopic observations (i-band<22) and an accompanying group catalogue to r-band<19.8. We demonstrate that even with some trade-off in sample size, an order of magnitude improvement on the accuracy of photometric redshifts is achievable when using galtag. This approach provides both refined photometric redshift measurements and group richness enhancement. In combination these products will hugely improve the scientific potential of both photometric and spectroscopic datasets. The galtag software will be made publicly available at https://github.com/pkaf/galtag.git.

A 1500 deg2 near infrared proper motion catalogue from the UKIDSS Large Area Survey

NASA Astrophysics Data System (ADS)

Smith, Leigh; Lucas, P. W.; Burningham, B.; Jones, H. R. A.; Smart, R. L.; Andrei, A. H.; Catalán, S.; Pinfield, D. J.

2014-02-01

The United Kingdom Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) began in 2005, with the start of the UKIDSS programme as a 7 year effort to survey roughly 4000 deg2 at high Galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of two epoch J band observations, with an epoch baseline greater than 2 years to calculate proper motions. We present a near-infrared proper motion catalogue for the 1500 deg2 of the two epoch LAS data, which includes 135 625 stellar sources and a further 88 324 with ambiguous morphological classifications, all with motions detected above the 5σ level. We developed a custom proper motion pipeline which we describe here. Our catalogue agrees well with the proper motion data supplied for a 300 deg2 subset in the current Wide Field Camera Science Archive (WSA) 10th data release (DR10) catalogue, and in various optical catalogues, but it benefits from a larger matching radius and hence a larger upper proper motion detection limit. We provide absolute proper motions, using LAS galaxies for the relative to absolute correction. By using local second-order polynomial transformations, as opposed to linear transformations in the WSA, we correct better for any local distortions in the focal plane, not including the radial distortion that is removed by the UKIDSS pipeline. We present the results of proper motion searches for new brown dwarfs and white dwarfs. We discuss 41 sources in the WSA DR10 overlap with our catalogue with proper motions >300 mas yr-1, several of which are new detections. We present 15 new candidate ultracool dwarf binary systems.

The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Chihway; et al.

Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200. A rapid decline in the matter density profile of the halo is expected near r_sp. We measure the galaxy number density and weak lensing mass profiles around RedMapper galaxy clusters in the first year Dark Energy Survey (DES) data. For amore » cluster sample with mean mass ~2.5 x 10^14 solar masses, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16 +/- 0.08 Mpc/h, consistent with earlier SDSS measurements of More et al. (2016) and Baxter et al. (2017). Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_sp=1.28 +/- 0.18 Mpc/h from the weak lensing data, in good agreement with our galaxy density measurements. Applying our analysis to different cluster and galaxy samples, we find that consistent with LambdaCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the redshift range of 0.3--0.6. We also find that potential systematic effects associated with the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness. We discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.« less

The JCMT Plane Survey: first complete data release - emission maps and compact source catalogue

NASA Astrophysics Data System (ADS)

Eden, D. J.; Moore, T. J. T.; Plume, R.; Urquhart, J. S.; Thompson, M. A.; Parsons, H.; Dempsey, J. T.; Rigby, A. J.; Morgan, L. K.; Thomas, H. S.; Berry, D.; Buckle, J.; Brunt, C. M.; Butner, H. M.; Carretero, D.; Chrysostomou, A.; Currie, M. J.; deVilliers, H. M.; Fich, M.; Gibb, A. G.; Hoare, M. G.; Jenness, T.; Manser, G.; Mottram, J. C.; Natario, C.; Olguin, F.; Peretto, N.; Pestalozzi, M.; Polychroni, D.; Redman, R. O.; Salji, C.; Summers, L. J.; Tahani, K.; Traficante, A.; diFrancesco, J.; Evans, A.; Fuller, G. A.; Johnstone, D.; Joncas, G.; Longmore, S. N.; Martin, P. G.; Richer, J. S.; Weferling, B.; White, G. J.; Zhu, M.

2017-08-01

We present the first data release of the James Clerk Maxwell Telescope Plane Survey (JPS), the JPS Public Release 1. JPS is an 850-μm continuum survey of six fields in the northern inner Galactic plane in a longitude range of ℓ = 7°-63°, made with the Submillimetre Common-User Bolometer Array 2. This first data release consists of emission maps of the six JPS regions with an average pixel-to-pixel noise of 7.19 mJy beam-1, when smoothed over the beam, and a compact source catalogue containing 7813 sources. The 95 per cent completeness limits of the catalogue are estimated at 0.04 Jy beam-1 and 0.3 Jy for the peak and integrated flux densities, respectively. The emission contained in the compact source catalogue is 42 ± 5 per cent of the total and, apart from the large-scale (greater than 8 arcmin) emission, there is excellent correspondence with features in the 500-μm Herschel maps. We find that, with two-dimensional matching, 98 ± 2 per cent of sources within the fields centred at ℓ = 20°, 30°, 40° and 50° are associated with molecular clouds, with 91 ± 3 per cent of the ℓ = 30° and 40° sources associated with dense molecular clumps. Matching the JPS catalogue to Herschel 70-μm sources, we find that 38 ± 1 per cent of sources show evidence of ongoing star formation. The JPS Public Release 1 images and catalogue will be a valuable resource for studies of star formation in the Galaxy and the role of environment and spiral arms in the star formation process.

Galaxy Groups in the 2Mass Redshift Survey

NASA Astrophysics Data System (ADS)

Lu, Yi; Yang, Xiaohu; Shi, Feng; Mo, H. J.; Tweed, Dylan; Wang, Huiyuan; Zhang, Youcai; Li, Shijie; Lim, S. H.

2016-11-01

A galaxy group catalog is constructed from the 2MASS Redshift Survey (2MRS) with the use of a halo-based group finder. The halo mass associated with a group is estimated using a “GAP” method based on the luminosity of the central galaxy and its gap with other member galaxies. Tests using mock samples show that this method is reliable, particularly for poor systems containing only a few members. On average, 80% of all the groups have completeness \\gt 0.8, and about 65% of the groups have zero contamination. Halo masses are estimated with a typical uncertainty of ∼ 0.35 {dex}. The application of the group finder to the 2MRS gives 29,904 groups from a total of 43,246 galaxies at z≤slant 0.08, with 5286 groups having two or more members. Some basic properties of this group catalog is presented, and comparisons are made with other group catalogs in overlap regions. With a depth to z∼ 0.08 and uniformly covering about 91% of the whole sky, this group catalog provides a useful database to study galaxies in the local cosmic web, and to reconstruct the mass distribution in the local universe.

The evolutionary sequence of post-starburst galaxies

NASA Astrophysics Data System (ADS)

Wilkinson, C. L.; Pimbblet, K. A.; Stott, J. P.

2017-12-01

There are multiple ways in which to select post-starburst galaxies in the literature. In this work, we present a study into how two well-used selection techniques have consequences on observable post-starburst galaxy parameters, such as colour, morphology and environment, and how this affects interpretations of their role in the galaxy duty cycle. We identify a master sample of H δ strong (EWH δ > 3Å) post-starburst galaxies from the value-added catalogue in the seventh data release of the Sloan Digital Sky Survey (SDSS DR7) over a redshift range 0.01 < z < 0.1. From this sample we select two E+A subsets, both having a very little [O II] emission (EW_[O II] > -2.5 Å) but one having an additional cut on EWHα (>-3 Å). We examine the differences in observables and AGN fractions to see what effect the H α cut has on the properties of post-starburst galaxies and what these differing samples can tell us about the duty cycle of post-starburst galaxies. We find that H δ strong galaxies peak in the 'blue cloud', E+As in the 'green valley' and pure E+As in the 'red sequence'. We also find that pure E+As have a more early-type morphology and a higher fraction in denser environments compared with the H δ strong and E+A galaxies. These results suggest that there is an evolutionary sequence in the post-starburst phase from blue discy galaxies with residual star formation to passive red early-types.

Simultaneous Multi-band Detection of Low Surface Brightness Galaxies with Markovian Modeling

NASA Astrophysics Data System (ADS)

Vollmer, B.; Perret, B.; Petremand, M.; Lavigne, F.; Collet, Ch.; van Driel, W.; Bonnarel, F.; Louys, M.; Sabatini, S.; MacArthur, L. A.

2013-02-01

We present to the astronomical community an algorithm for the detection of low surface brightness (LSB) galaxies in images, called MARSIAA (MARkovian Software for Image Analysis in Astronomy), which is based on multi-scale Markovian modeling. MARSIAA can be applied simultaneously to different bands. It segments an image into a user-defined number of classes, according to their surface brightness and surroundings—typically, one or two classes contain the LSB structures. We have developed an algorithm, called DetectLSB, which allows the efficient identification of LSB galaxies from among the candidate sources selected by MARSIAA. The application of the method to two and three bands simultaneously was tested on simulated images. Based on our tests, we are confident that we can detect LSB galaxies down to a central surface brightness level of only 1.5 times the standard deviation from the mean pixel value in the image background. To assess the robustness of our method, the method was applied to a set of 18 B- and I-band images (covering 1.3 deg2 in total) of the Virgo Cluster to which Sabatini et al. previously applied a matched-filter dwarf LSB galaxy search algorithm. We have detected all 20 objects from the Sabatini et al. catalog which we could classify by eye as bona fide LSB galaxies. Our method has also detected four additional Virgo Cluster LSB galaxy candidates undetected by Sabatini et al. To further assess the completeness of the results of our method, both MARSIAA, SExtractor, and DetectLSB were applied to search for (1) mock Virgo LSB galaxies inserted into a set of deep Next Generation Virgo Survey (NGVS) gri-band subimages and (2) Virgo LSB galaxies identified by eye in a full set of NGVS square degree gri images. MARSIAA/DetectLSB recovered ~20% more mock LSB galaxies and ~40% more LSB galaxies identified by eye than SExtractor/DetectLSB. With a 90% fraction of false positives from an entirely unsupervised pipeline, a completeness of 90% is reached

Evaluation of a mock interview session on residency interview skills.

PubMed

Buckley, Kelsey; Karr, Samantha; Nisly, Sarah A; Kelley, Kristi

2018-04-01

To evaluate the impact of student pharmacist participation in a mock interview session on confidence level and preparation regarding residency interview skills. The study setting was a mock interview session, held in conjunction with student programming at the American College of Clinical Pharmacy (ACCP) Annual Meeting. Prior to the mock interview session, final year student pharmacists seeking residency program placement were asked to complete a pre-session survey assessing confidence level for residency interviews. Each student pharmacist participated in up to three mock interviews. A post-session survey evaluating confidence level was then administered to consenting participants. Following the American Society for Health-System Pharmacists (ASHP) Pharmacy Resident Matching Program (RMP), a post-match electronic survey was sent to study participants to determine their perception of the influence of the mock interview session on achieving successful interactions during residency interviews. A total of 59 student pharmacists participated in the mock interview session and completed the pre-session survey. Participants completing the post-session survey (88%, n = 52) unanimously reported an enhanced confidence in interviewing skills following the session. Thirty responders reported a program match rate of 83%. Approximately 97% (n = 29) of the respondents agreed or strongly agreed that the questions asked during the mock interview session were reflective of questions asked during residency interviews. Lessons learned from this mock interview session can be applied to PGY1 residency mock interview sessions held locally, regionally, and nationally. Students participating in the ACCP Mock Interview Session recognized the importance of the interview component in obtaining a postgraduate year 1 (PGY1) pharmacy residency. Copyright © 2017 Elsevier Inc. All rights reserved.

Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments

NASA Astrophysics Data System (ADS)

Takahashi, Ryuichi; Hamana, Takashi; Shirasaki, Masato; Namikawa, Toshiya; Nishimichi, Takahiro; Osato, Ken; Shiroyama, Kosei

2017-11-01

We present 108 full-sky gravitational lensing simulation data sets generated by performing multiple-lens plane ray-tracing through high-resolution cosmological N-body simulations. The data sets include full-sky convergence and shear maps from redshifts z = 0.05 to 5.3 at intervals of 150 {h}-1{Mpc} comoving radial distance (corresponding to a redshift interval of {{Δ }}z≃ 0.05 at the nearby universe), enabling the construction of a mock shear catalog for an arbitrary source distribution up to z = 5.3. The dark matter halos are identified from the same N-body simulations with enough mass resolution to resolve the host halos of the Sloan Digital Sky Survey (SDSS) CMASS and luminous red galaxies (LRGs). Angular positions and redshifts of the halos are provided by a ray-tracing calculation, enabling the creation of a mock halo catalog to be used for galaxy-galaxy and cluster-galaxy lensing. The simulation also yields maps of gravitational lensing deflections for a source redshift at the last scattering surface, and we provide 108 realizations of lensed cosmic microwave background (CMB) maps in which the post-Born corrections caused by multiple light scattering are included. We present basic statistics of the simulation data, including the angular power spectra of cosmic shear, CMB temperature and polarization anisotropies, galaxy-galaxy lensing signals for halos, and their covariances. The angular power spectra of the cosmic shear and CMB anisotropies agree with theoretical predictions within 5% up to {\\ell }=3000 (or at an angular scale θ > 0.5 arcmin). The simulation data sets are generated primarily for the ongoing Subaru Hyper Suprime-Cam survey, but are freely available for download at http://cosmo.phys.hirosaki-u.ac.jp/takahasi/allsky_raytracing/.

Search For Star Cluster Age Gradients Across Spiral Arms of Three LEGUS Disk Galaxies

NASA Astrophysics Data System (ADS)

Shabani, F.; Grebel, E. K.; Pasquali, A.; D'Onghia, E.; Gallagher, J. S.; Adamo, A.; Messa, M.; Elmegreen, B. G.; Dobbs, C.; Gouliermis, D. A.; Calzetti, D.; Grasha, K.; Elmegreen, D. M.; Cignoni, M.; Dale, D. A.; Aloisi, A.; Smith, L. J.; Tosi, M.; Thilker, D. A.; Lee, J. C.; Sabbi, E.; Kim, H.; Pellerin, A.

2018-05-01

One of the main theories for explaining the formation of spiral arms in galaxies is the stationary density wave theory. This theory predicts the existence of an age gradient across the arms. We use the stellar cluster catalogues of the galaxies NGC 1566, M51a, and NGC 628 from the Legacy Extragalactic UV Survey (LEGUS) program. In order to test for the possible existence of an age sequence across the spiral arms, we quantified the azimuthal offset between star clusters of different ages in our target galaxies. We found that NGC 1566, a grand-design spiral galaxy with bisymmetric arms and a strong bar, shows a significant age gradient across the spiral arms that appears to be consistent with the prediction of the stationary density wave theory. In contrast, M51a with its two well-defined spiral arms and a weaker bar does not show an age gradient across the arms. In addition, a comparison with non-LEGUS star cluster catalogues for M51a yields similar results. We believe that the spiral structure of M51a is not the result of a stationary density wave with a fixed pattern speed. Instead, tidal interactions could be the dominant mechanism for the formation of spiral arms. We also found no offset in the azimuthal distribution of star clusters with different ages across the weak spiral arms of NGC 628.

The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerke, Brian F.; /UC, Berkeley; Newman, Jeffrey A.

2012-02-14

We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 {<=} z {<=} 1.4, over one square degree on the sky. Groups are identified using an algorithm (the Voronoi-Delaunay Method) that has been shown to accurately reproduce the statistics of groups in simulated DEEP2-like samples. We optimize this algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs and assessing the results using a stringent set of criteria for measuring group-findingmore » success, which we develop and describe in detail here. We find in particular that the group-finder can successfully identify {approx}78% of real groups and that {approx}79% of the galaxies that are true members of groups can be identified as such. Conversely, we estimate that {approx}55% of the groups we find can be definitively identified with real groups and that {approx}46% of the galaxies we place into groups are interloper field galaxies. Most importantly, we find that it is possible to measure the distribution of groups in redshift and velocity dispersion, n({sigma}, z), to an accuracy limited by cosmic variance, for dispersions greater than 350 km s{sup -1}. We anticipate that such measurements will allow strong constraints to be placed on the equation of state of the dark energy in the future. Finally, we present the first DEEP2 group catalog, which assigns 32% of the galaxies to 899 distinct groups with two or more members, 153 of which have velocity dispersions above 350 km s{sup -1}. We provide locations, redshifts and properties for this high-dispersion subsample. This catalog represents the largest sample to date of spectroscopically detected groups at z {approx} 1.« less

Korea Institute for Advanced Study Value-Added Galaxy Catalog

NASA Astrophysics Data System (ADS)

Choi, Yun-Young; Han, Du-Hwan; Kim, Sungsoo S.

2010-12-01

We present the Korea Institute for Advanced Study Value-Added Galaxy Catalog (KIAS VAGC),a catalog of galaxies based on the Large Scale Structure (LSS) sample of New York University Value-Added Galaxy Catalog (NYU VAGC) Data Release 7. Our catalog supplements redshifts of 10,497 galaxies with 10 < r_{P} ≤ 17.6 (1455 with 10 < r_{P} ≤ 14.5) to the NYU VAGC LSS sample. Redshifts from various existing catalogs such as the Updated Zwicky Catalog, the IRAS Point Source Catalog Redshift Survey, the Third Reference Catalogue of Bright Galaxies, and the Two Degree Field Galaxy Redshift Survey have been put into the NYU VAGC photometric catalog. Our supplementation significantly improves spectroscopic completeness: the area covered by the spectroscopic sample with completeness higher than 95% increases from 2.119 to 1.737 sr.Our catalog also provides morphological types of all galaxies that are determined by the automated morphology classification scheme of Park & Choi (2005), and related parameters, together with fundamental photometry parameters supplied by the NYU VAGC. Our catalog contains matches to objects in the Max Planck for Astronomy (MPA) & Johns Hopkins University (JHU) spectrum measurements (Data Release 7). This new catalog, the KIAS VAGC, is complementary to the NYU VAGC and MPA-JHU catalog.

The distribution of early- and late-type galaxies in the Coma cluster

NASA Technical Reports Server (NTRS)

Doi, M.; Fukugita, M.; Okamura, S.; Turner, E. L.

1995-01-01

The spatial distribution and the morohology-density relation of Coma cluster galaxies are studied using a new homogeneous photmetric sample of 450 galaxies down to B = 16.0 mag with quantitative morphology classification. The sample covers a wide area (10 deg X 10 deg), extending well beyond the Coma cluster. Morphological classifications into early- (E+SO) and late-(S) type galaxies are made by an automated algorithm using simple photometric parameters, with which the misclassification rate is expected to be approximately 10% with respect to early and late types given in the Third Reference Catalogue of Bright Galaxies. The flattened distribution of Coma cluster galaxies, as noted in previous studies, is most conspicuously seen if the early-type galaxies are selected. Early-type galaxies are distributed in a thick filament extended from the NE to the WSW direction that delineates a part of large-scale structure. Spiral galaxies show a distribution with a modest density gradient toward the cluster center; at least bright spiral galaxies are present close to the center of the Coma cluster. We also examine the morphology-density relation for the Coma cluster including its surrounding regions.

Cataloguing Standards; The Report of the Canadian Task Group on Cataloguing Standards.

ERIC Educational Resources Information Center

National Library of Canada, Ottawa (Ontario).

Following the recommendations of the National Conference on Cataloguing Standards held at the National Library of Canada in May 1970, a Canadian Task Group on Cataloguing Standards was set up to study and identify present deficiencies in the organizing and processing of Canadian material, and the cataloging problems of Canadian libraries, and to…

How to Reconcile the Observed Velocity Function of Galaxies with Theory

NASA Astrophysics Data System (ADS)

Brooks, Alyson M.; Papastergis, Emmanouil; Christensen, Charlotte R.; Governato, Fabio; Stilp, Adrienne; Quinn, Thomas R.; Wadsley, James

2017-11-01

Within a Λ cold dark matter (ΛCDM) scenario, we use high-resolution cosmological simulations spanning over four orders of magnitude in galaxy mass to understand the deficit of dwarf galaxies in observed velocity functions (VFs). We measure velocities in as similar a way as possible to observations, including generating mock H I data cubes for our simulated galaxies. We demonstrate that this apples-to-apples comparison yields an “observed” VF in agreement with observations, reconciling the large number of low-mass halos expected in a ΛCDM cosmological model with the low number of observed dwarfs at a given velocity. We then explore the source of the discrepancy between observations and theory and conclude that the dearth of observed dwarf galaxies is primarily explained by two effects. The first effect is that galactic rotational velocities derived from the H I linewidth severely underestimate the maximum halo velocity. The second effect is that a large fraction of halos at the lowest masses are too faint to be detected by current galaxy surveys. We find that cored DM density profiles can contribute to the lower observed velocity of galaxies but only for galaxies in which the velocity is measured interior to the size of the core (˜3 kpc).

Gathering dust: A galaxy-wide study of dust emission from cloud complexes in NGC 300

NASA Astrophysics Data System (ADS)

Riener, M.; Faesi, C. M.; Forbrich, J.; Lada, C. J.

2018-05-01

Aims: We use multi-band observations by the Herschel Space Observatory to study the dust emission properties of the nearby spiral galaxy NGC 300. We compile a first catalogue of the population of giant dust clouds (GDCs) in NGC 300, including temperature and mass estimates, and give an estimate of the total dust mass of the galaxy. Methods: We carried out source detection with the multiwavelength source extraction algorithm getsources. We calculated physical properties, including mass and temperature, of the GDCs from five-band Herschel PACS and SPIRE observations from 100 to 500 μm; the final size and mass estimates are based on the observations at 250 μm that have an effective spatial resolution of 170 pc. We correlated our final catalogue of GDCs to pre-existing catalogues of HII regions to infer the number of GDCs associated with high-mass star formation and determined the Hα emission of the GDCs. Results: Our final catalogue of GDCs includes 146 sources, 90 of which are associated with known HII regions. We find that the dust masses of the GDCs are completely dominated by the cold dust component and range from 1.1 × 103 to 1.4 × 104 M⊙. The GDCs have effective temperatures of 13-23 K and show a distinct cold dust effective temperature gradient from the centre towards the outer parts of the stellar disk. We find that the population of GDCs in our catalogue constitutes 16% of the total dust mass of NGC 300, which we estimate to be about 5.4 × 106 M⊙. At least about 87% of our GDCs have a high enough average dust mass surface density to provide sufficient shielding to harbour molecular clouds. We compare our results to previous pointed molecular gas observations in NGC 300 and results from other nearby galaxies and also conclude that it is very likely that most of our GDCs are associated with complexes of giant molecular clouds. The catalogue is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http

The AC 2000.2 Catalogue

NASA Astrophysics Data System (ADS)

Urban, S. E.; Corbin, T. E.; Wycoff, G. L.; Makarov, V. V.; Høg, E.; Fabricius, C.

2001-12-01

For over 100 years, the international project known as the Astrographic Catalogue -- which involved 20 observatories tasked to photograph the sky -- has held an unfulfilled promised of yielding a wealth of astrometric information. This promise was not realized due to the inadequate reductions of the project's plates. However, in 1997 the U.S. Naval Observatory (USNO) completed the reductions of the 22,660 plates. That catalogue, named the AC 2000, contained positions and magnitudes for 4.6 million stars down to about v magnitude 12.5. Due to the early epochs of the data -- averaging 1907 -- and the positional accuracies -- between 150 and 400 milliarcseconds -- the data are extremely valuable in computing proper motions. In 1997, these positions were used to form the proper motions of the ACT Reference Catalogue. In 1999, USNO and Copenhagen University Observatory (CUO) partnered to create the Tycho-2 Catalogue. The CUO group re-analyzed the data from the Tycho experiment on the Hipparcos satellite. The USNO group re-analyzed over 140 positional catalogs which were combined with the expanded Tycho positions from the CUO group to compute the Tycho-2 proper motions. The largest contributor to these proper motions was the re-analyzed Astrographic Catalogue; the latest version being known as the AC 2000.2 Catalogue. There are two major differences between the AC 2000 and the AC 2000.2. First, the reference catalog used in AC 2000.2 was an expanded version of the Astrographic Catalogue Reference Stars that was rigorously derived on the Hipparcos Celestial Reference Frame. The second is that AC 2000.2 contains photometry from Tycho-2, where available. A description of the AC 2000.2 Catalogue, the reduction techniques used, how it compares with the 1997 version, and information on obtaining the data will be presented.

Lyman-α emitters in the context of hierarchical galaxy formation: predictions for VLT/MUSE surveys

NASA Astrophysics Data System (ADS)

Garel, T.; Guiderdoni, B.; Blaizot, J.

2016-02-01

The VLT/Multi Unit Spectrograph Explorer (MUSE) integral-field spectrograph can detect Lyα emitters (LAE) in the redshift range 2.8 ≲ z ≲ 6.7 in a homogeneous way. Ongoing MUSE surveys will notably probe faint Lyα sources that are usually missed by current narrow-band surveys. We provide quantitative predictions for a typical wedding-cake observing strategy with MUSE based on mock catalogues generated with a semi-analytic model of galaxy formation coupled to numerical Lyα radiation transfer models in gas outflows. We expect ≈1500 bright LAEs (FLyα ≳ 10-17 erg s-1 cm-2) in a typical shallow field (SF) survey carried over ≈100 arcmin2 , and ≈2000 sources as faint as 10-18 erg s-1 cm-2 in a medium-deep field (MDF) survey over 10 arcmin2 . In a typical deep field (DF) survey of 1 arcmin2 , we predict that ≈500 extremely faint LAEs (FLyα ≳ 4 × 10-19 erg s-1 cm-2) will be found. Our results suggest that faint Lyα sources contribute significantly to the cosmic Lyα luminosity and SFR budget. While the host haloes of bright LAEs at z ≈ 3 and 6 have descendants with median masses of 2 × 1012 and 5 × 1013 M⊙, respectively, the faintest sources detectable by MUSE at these redshifts are predicted to reside in haloes which evolve into typical sub-L* and L* galaxy haloes at z = 0. We expect typical DF and MDF surveys to uncover the building blocks of Milky Way-like objects, even probing the bulk of the stellar mass content of LAEs located in their progenitor haloes at z ≈ 3.

Senior Medical Student Mock Interview Program in Pediatrics.

PubMed

Multerer, Sara; Carothers, Becky; Patel, Pradip D; Ziegler, Craig; Rowland, Michael; Davis, Deborah Winders

2016-02-01

Residency interviews play an integral part in medical residency placement. We aimed to develop and evaluate a mock interview program for fourth-year medical students interested in a pediatric specialty. A mock interview program for fourth-year medical students interested in pediatrics was developed and implemented. Preinterview quantitative data and postinterview qualitative data were collected. Fifty-nine students completed the program across three consecutive academic years. Preinterview surveys were completed regarding comfort and confidence levels specific to aspects of the interview process. Descriptive analyses were used. In addition, a focus group was held with nine of the participating students to obtain qualitative data via a paper blog process. Themes in student responses were identified through constant comparative analysis. Before the mock interview, students were most uncomfortable with introductory and closing remarks and their confidence levels varied by topic. A thematic analysis of focus group data identified five themes (preparation, stress reduction, interview process familiarity, confidence of skills, and receiving feedback) for which the mock interviews were most helpful. Implementation of a mock interview program was feasible and acceptable for senior medical students and may improve comfort and confidence levels in the residency interview process. Further longitudinal research is needed.

Galaxy And Mass Assembly (GAMA): end of survey report and data release 2

NASA Astrophysics Data System (ADS)

Liske, J.; Baldry, I. K.; Driver, S. P.; Tuffs, R. J.; Alpaslan, M.; Andrae, E.; Brough, S.; Cluver, M. E.; Grootes, M. W.; Gunawardhana, M. L. P.; Kelvin, L. S.; Loveday, J.; Robotham, A. S. G.; Taylor, E. N.; Bamford, S. P.; Bland-Hawthorn, J.; Brown, M. J. I.; Drinkwater, M. J.; Hopkins, A. M.; Meyer, M. J.; Norberg, P.; Peacock, J. A.; Agius, N. K.; Andrews, S. K.; Bauer, A. E.; Ching, J. H. Y.; Colless, M.; Conselice, C. J.; Croom, S. M.; Davies, L. J. M.; De Propris, R.; Dunne, L.; Eardley, E. M.; Ellis, S.; Foster, C.; Frenk, C. S.; Häußler, B.; Holwerda, B. W.; Howlett, C.; Ibarra, H.; Jarvis, M. J.; Jones, D. H.; Kafle, P. R.; Lacey, C. G.; Lange, R.; Lara-López, M. A.; López-Sánchez, Á. R.; Maddox, S.; Madore, B. F.; McNaught-Roberts, T.; Moffett, A. J.; Nichol, R. C.; Owers, M. S.; Palamara, D.; Penny, S. J.; Phillipps, S.; Pimbblet, K. A.; Popescu, C. C.; Prescott, M.; Proctor, R.; Sadler, E. M.; Sansom, A. E.; Seibert, M.; Sharp, R.; Sutherland, W.; Vázquez-Mata, J. A.; van Kampen, E.; Wilkins, S. M.; Williams, R.; Wright, A. H.

2015-09-01

The Galaxy And Mass Assembly (GAMA) survey is one of the largest contemporary spectroscopic surveys of low redshift galaxies. Covering an area of ˜286 deg2 (split among five survey regions) down to a limiting magnitude of r < 19.8 mag, we have collected spectra and reliable redshifts for 238 000 objects using the AAOmega spectrograph on the Anglo-Australian Telescope. In addition, we have assembled imaging data from a number of independent surveys in order to generate photometry spanning the wavelength range 1 nm-1 m. Here, we report on the recently completed spectroscopic survey and present a series of diagnostics to assess its final state and the quality of the redshift data. We also describe a number of survey aspects and procedures, or updates thereof, including changes to the input catalogue, redshifting and re-redshifting, and the derivation of ultraviolet, optical and near-infrared photometry. Finally, we present the second public release of GAMA data. In this release, we provide input catalogue and targeting information, spectra, redshifts, ultraviolet, optical and near-infrared photometry, single-component Sérsic fits, stellar masses, Hα-derived star formation rates, environment information, and group properties for all galaxies with r < 19.0 mag in two of our survey regions, and for all galaxies with r < 19.4 mag in a third region (72 225 objects in total). The data base serving these data is available at http://www.gama-survey.org/.

Surface Photometric Properties of HII Galaxies

NASA Astrophysics Data System (ADS)

Vajgel, B.; Telles, E.

2009-05-01

HII galaxies are dwarf galaxies undergoing violent star formation. They were firstly selected by objective-prism spectroscopy and were object of extensive studies to characterize their physical conditions of the interstellar medium. Their SFR together with their low Z raised the question whether some of them can be truly ``young'' galaxies. To infer the SFH, one needs information in a large spectral range. We obtained images in the optical region of the spectrum with the 0.6 m B&C and the 1.6 m telescopes at the Laboratório Nacional de Astrofísica, for a sample of 50 objects in B, V, R and I, which combined with recent evolutionary models, enable us to deduce the stellar population content and its spatial distribution. These seem to be the nearest youngest galaxies that can be studied in detail, and their structural properties offer important indications about the evolutionary relation and the origin of dwarf galaxies in the universe. With this sample we built a morphological catalogue with broad-band photometry, including the structural analysis through the brightness profiles. The initial analysis suggests that the galaxies can be segregated in two broad classes, in agreement with what had already been proposed in the literature; Type I have irregular envelopes with signs of perturbation and turn out to the more luminous sub-sample; while Type II have regular external isophotes and are less luminous. The brightness profiles are well represented by exponential fits, as in irregular and elliptical dwarf galaxies. However, HII galaxies are more compact in comparison with their more diffuse counterparts. We study the behavior of the HII galaxies in the metallicity-luminosity plane. This relation, interpreted as a relation between the mass and the metallicity of dwarf galaxies of low surface brightness (dE and dIrr), has direct implications for their formation and evolution, and over the possible evolutionary links between HII galaxies and other types of dwarf

The Munich Near-Infrared Cluster Survey - IX. Galaxy evolution to z ~ 2 from optically selected catalogues†‡

NASA Astrophysics Data System (ADS)

Feulner, Georg; Goranova, Yuliana; Hopp, Ulrich; Gabasch, Armin; Bender, Ralf; Botzler, Christine S.; Drory, Niv

2007-06-01

We present B-, R- and I-band-selected galaxy catalogues based on the Munich Near-Infrared Cluster Survey (MUNICS) which, together with the previously used K-selected sample, serve as an important probe of galaxy evolution in the redshift range 0 <~ z <~ 2. Furthermore, used in comparison they are ideally suited to study selection effects in extragalactic astronomy. The construction of the B-, R- and I-selected photometric catalogues, containing ~9000, ~9000 and ~6000 galaxies, respectively, is described in detail. The catalogues reach 50 per cent completeness limits for point sources of B ~= 24.5 mag, R ~= 23.5 mag and I ~= 22.5 mag and cover an area of about 0.3deg2. Photometric redshifts are derived for all galaxies with an accuracy of δz/(1 + z) ~= 0.057, very similar to the K-selected sample. Galaxy number counts in the B, V, R, I, J and K bands demonstrate the quality of the data set. The rest-frame colour distributions of galaxies at different selection bands and redshifts suggest that the most-massive galaxies have formed the bulk of their stellar population at earlier times and are essentially in place at redshift unity. We investigate the influence of selection band and environment on the specific star formation rate (SSFR). We find that K-band selection indeed comes close to selection in stellar mass, while B-band selection purely selects galaxies in SFR. We use a galaxy group catalogue constructed on the K-band-selected MUNICS sample to study possible differences of the SSFR between the field and the group environment, finding a marginally lower average SSFR in groups as compared to the field, especially at lower redshifts. The field-galaxy luminosity function in the B and R band as derived from the R-selected sample evolves out to z ~= 2 in the sense that the characteristic luminosity increases but the number density decreases. This effect is smaller at longer rest-frame wavelengths and gets more pronounced at shorter wavelengths. Parametrizing the

The SPM Kinematic Catalogue of Planetary Nebulae

NASA Astrophysics Data System (ADS)

López, J. A.; Richer, M.; Riesgo, H.; Steffen, W.; Meaburn, J.; García-Segura, G.; Escalante, K.

2006-06-01

We present a progress report on the San Pedro Mártir Kinematic Catalogue of Planetary Nebulae. Both, galactic PNe from the disk, bulge and halo populations, and PNe from galaxies in the local group from a diverse range of metallicities have been observed. Most of the observations have been made with the 2.1-m SPM telescope and the Manchester Echelle Spectrometer (Meaburn et al. 2003, RevMexAA, 39, 185). The data consists of spatially resoved long slit spectra at resolutions of ˜ 10 km s^{-1}. For most galactic targets more than one slit positions has been observed. The interpretation of the 3D structures and outflows derived from the kinematic data is being performed with the aid of SHAPE (see the contributions by Steffen, López, & Escalante, Steffen & López in this symposium). This unique database of high dispersion spectra will allow a firm characterisation of nebular shell properties in relation to progenitors from diverse stellar populations.

The Cosmic Skidmark: witnessing galaxy transformation at z = 0.19

NASA Astrophysics Data System (ADS)

Murphy, David N. A.

2015-02-01

We present an early-look analysis of the ``Cosmic Skidmark''. Discovered following visual inspection of the Geach, Murphy & Bower (2011) SDSS Stripe 82 cluster catalogue generated by ORCA (an automated cluster algorithm searching for red-sequences; Murphy, Geach & Bower 2012), this z = 0.19 1.4L* galaxy appears to have been caught in the rare act of transformation while accreting onto an estimated 1013-1014 h -1 M⊙-mass galaxy group. SDSS spectroscopy reveals clear signatures of star formation whilst deep optical imaging reveals a pronounced 50 kpc cometary tail. Pending completion of our ALMA Cycle 2 and IFU observations, we show here preliminary analysis of this target.

Understanding Galaxy Shapes Across Cosmic Time Using The IllustrisTNG Simulation

NASA Astrophysics Data System (ADS)

Genel, Shy

2017-08-01

Legacy HST observations have enabled groundbreaking measurements of galaxy structure over cosmic time, measurements that still require theoretical interpretation in the context of a comprehensive galaxy evolution model. This proposed research aims at significantly promoting our understanding of the shapes of galaxies as quantified by their principal axes ratios. The main tool we propose to use is IllustrisTNG, a suite consisting of two of the largest cosmological hydrodynamical simulations run to date, which contain resolved galaxy populations (thousands of L* galaxies) that represent a state-of-the-art match to observed galaxies. In Part I of the program, we will use the simulations to create mock images and study the dependence of projected shape measurements on various factors: shape estimator, observed band, the presence of dust, radial and surface brightness cuts, and noise. We will then perform apples-to-apples comparison with observations (including HST), and provide predictions for archival as well as future observations. Further, we will quantify the intrinsic, three-dimensional, shape distribution of galaxies as a function of various galaxy parameters: redshift, mass, color, and size. In Part II of the program, we will develop theoretical insights into the physical mechanisms driving these results. We will study how galaxy shapes relate to angular momentum and merger history, and will follow the shape evolution of individual galaxies over time, looking for correlations to the evolution of other galaxy properties, e.g. size and SFR. We will also study galaxy shape relations to dark matter halo shape, thereby providing input for high-precision cosmic shear models.

Catalogue of Icelandic Volcanoes

NASA Astrophysics Data System (ADS)

Ilyinskaya, Evgenia; Larsen, Gudrun; Gudmundsson, Magnus T.; Vogfjord, Kristin; Pagneux, Emmanuel; Oddsson, Bjorn; Barsotti, Sara; Karlsdottir, Sigrun

2016-04-01

The Catalogue of Icelandic Volcanoes is a newly developed open-access web resource in English intended to serve as an official source of information about active volcanoes in Iceland and their characteristics. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the effort of FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite. Volcanic activity in Iceland occurs on volcanic systems that usually comprise a central volcano and fissure swarm. Over 30 systems have been active during the Holocene (the time since the end of the last glaciation - approximately the last 11,500 years). In the last 50 years, over 20 eruptions have occurred in Iceland displaying very varied activity in terms of eruption styles, eruptive environments, eruptive products and the distribution lava and tephra. Although basaltic eruptions are most common, the majority of eruptions are explosive, not the least due to magma-water interaction in ice-covered volcanoes. Extensive research has taken place on Icelandic volcanism, and the results reported in numerous scientific papers and other publications. In 2010, the International Civil Aviation Organisation (ICAO) funded a 3 year project to collate the current state of knowledge and create a comprehensive catalogue readily available to decision makers, stakeholders and the general public. The work on the Catalogue began in 2011, and was then further supported by the Icelandic government and the EU through the FP7 project FUTUREVOLC. The Catalogue of Icelandic Volcanoes is a collaboration of the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere. The Catalogue is built up of chapters with texts and various

High-redshift radio galaxies and divergence from the CMB dipole

NASA Astrophysics Data System (ADS)

Colin, Jacques; Mohayaee, Roya; Rameez, Mohamed; Sarkar, Subir

2017-10-01

Previous studies have found our velocity in the rest frame of radio galaxies at high redshift to be much larger than that inferred from the dipole anisotropy of the cosmic microwave background. We construct a full sky catalogue, NVSUMSS, by merging the NRAO VLA Sky Survey and the Sydney University Molonglo Sky Survey catalogues and removing local sources by various means including cross-correlating with the 2MASS Redshift Survey catalogue. We take into account both aberration and Doppler boost to deduce our velocity from the hemispheric number count asymmetry, as well as via a three-dimensional linear estimator. Both its magnitude and direction depend on cuts made to the catalogue, e.g. on the lowest source flux; however these effects are small. From the hemispheric number count asymmetry we obtain a velocity of 1729 ± 187 km s-1, I.e. about four times larger than that obtained from the cosmic microwave background dipole, but close in direction, towards RA=149° ± 2°, Dec. = -17° ± 12°. With the three-dimensional estimator, the derived velocity is 1355 ± 174 km s-1 towards RA = 141° ± 11°, Dec. = -9° ± 10°. We assess the statistical significance of these results by comparison with catalogues of random distributions, finding it to be 2.81σ (99.75 per cent confidence).

Astronomical Catalogues - Definition Elements and Afterlife

NASA Astrophysics Data System (ADS)

Jaschek, C.

1984-09-01

Based on a look at the different meanings of the term catalogue (or catalog), a definition is proposed. In an analysis of the main elements, a number of requirements that catalogues should satisfy are pointed out. A section is devoted to problems connected with computer-readable versions of printed catalogues.

Clustering of galaxies with f(R) gravity

NASA Astrophysics Data System (ADS)

Capozziello, Salvatore; Faizal, Mir; Hameeda, Mir; Pourhassan, Behnam; Salzano, Vincenzo; Upadhyay, Sudhaker

2018-02-01

Based on thermodynamics, we discuss the galactic clustering of expanding Universe by assuming the gravitational interaction through the modified Newton's potential given by f(R) gravity. We compute the corrected N-particle partition function analytically. The corrected partition function leads to more exact equations of state of the system. By assuming that the system follows quasi-equilibrium, we derive the exact distribution function that exhibits the f(R) correction. Moreover, we evaluate the critical temperature and discuss the stability of the system. We observe the effects of correction of f(R) gravity on the power-law behaviour of particle-particle correlation function also. In order to check the feasibility of an f(R) gravity approach to the clustering of galaxies, we compare our results with an observational galaxy cluster catalogue.

VizieR Online Data Catalog: KGS EoR0 Catalogue (Carroll+, 2016)

NASA Astrophysics Data System (ADS)

Carroll, P. A.; Line, J.; Morales, M. F.; Barry, N.; Beardsley, A. P.; Hazelton, B. J.; Jacobs, D. C.; Pober, J. C.; Sullivan, I. S.; Webster, R. L.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; de Oliveira-Costa, A.; Dillon, J. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kim, Hs.; Kratzenberg, E.; Lenc, E.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morgan, E.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, S. K.; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Trott, C. M.; Waterson, M.; Wayth, R. B.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.

2018-01-01

The MWA EoR0 field is centred at RA=0h and Dec=-27°, and was chosen because it has no bright complex sources in the primary field of view. The FWHM of the antenna beam is approximately 20°, but sources in the edges of the beam and first few side lobes are clearly visible and should be subtracted (Thyagarajan et al., 2015ApJ...804...14T, 2015ApJ...807L..28T; Pober et al., 2016ApJ...819....8P). For this catalogue we concentrate on identifying sources in the primary beam but go out to the 5 per cent power point (nearly first beam null, ~1400deg2). The data for this catalogue include 752min snapshot observations (112s consecutive integrations with 8s gaps) from the night of 2013 August 23. The observations were made at 182MHz with 31MHz bandwidth and cover 2.5h in total. This process for source finding, measurement, and classification has been termed KATALOGSS (KDD Astrometry, Trueness, and Apparent Luminosity of Galaxies in Snapshot Surveys; hereafter abbreviated to KGS). (1 data file).

The Laniakea supercluster of galaxies.

PubMed

Tully, R Brent; Courtois, Hélène; Hoffman, Yehuda; Pomarède, Daniel

2014-09-04

Galaxies congregate in clusters and along filaments, and are missing from large regions referred to as voids. These structures are seen in maps derived from spectroscopic surveys that reveal networks of structure that are interconnected with no clear boundaries. Extended regions with a high concentration of galaxies are called 'superclusters', although this term is not precise. There is, however, another way to analyse the structure. If the distance to each galaxy from Earth is directly measured, then the peculiar velocity can be derived from the subtraction of the mean cosmic expansion, the product of distance times the Hubble constant, from observed velocity. The peculiar velocity is the line-of-sight departure from the cosmic expansion and arises from gravitational perturbations; a map of peculiar velocities can be translated into a map of the distribution of matter. Here we report a map of structure made using a catalogue of peculiar velocities. We find locations where peculiar velocity flows diverge, as water does at watershed divides, and we trace the surface of divergent points that surrounds us. Within the volume enclosed by this surface, the motions of galaxies are inward after removal of the mean cosmic expansion and long range flows. We define a supercluster to be the volume within such a surface, and so we are defining the extent of our home supercluster, which we call Laniakea.

Stellar population in star formation regions of galaxies

NASA Astrophysics Data System (ADS)

Gusev, Alexander S.; Shimanovskaya, Elena V.; Shatsky, Nikolai I.; Sakhibov, Firouz; Piskunov, Anatoly E.; Kharchenko, Nina V.

2018-05-01

We developed techniques for searching young unresolved star groupings (clusters, associations, and their complexes) and of estimating their physical parameters. Our study is based on spectroscopic, spectrophotometric, and UBVRI photometric observations of 19 spiral galaxies. In the studied galaxies, we found 1510 objects younger than 10 Myr and present their catalogue. Having combined photometric and spectroscopic data, we derived extinctions, chemical abundances, sizes, ages, and masses of these groupings. We discuss separately the specific cases, when the gas extinction does not agree with the interstellar one. We assume that this is due to spatial offset of Hii clouds with respect to the related stellar population.We developed a method to estimate age of stellar population of the studied complexes using their morphology and the relation with associated H emission region. In result we obtained the estimates of chemical abundances for 80, masses for 63, and ages for 57 young objects observed in seven galaxies.

Building 9 ISS mock-ups and trainers

NASA Image and Video Library

1999-08-02

Photographic documentation showing the bldg. 9 ISS module mock-ups and trainers. Views include: various overall views of the configuration of the ISS module trainers on the floor of bldg. 9 (08445-46, 08449-51, 08458-61, 08464-65, 08469, 08471, 08476); various portions of the mock-ups (08447-48, 08470); views of the Node 2, Experiment Module and Logistics Module (08452); Node 2 (08453, 08466); Destiny and Node 2 (08454); Destiny, Unity and Airlock (08455); Zarya, Service Module and shuttle mock-ups (08456); Logistics Module and Experiment Module (08457, 08468); various views of Columbia, Node 2 and Destiny (08462-63); Columbus, Node 2, Experiment Module and Logistics Module (08467); U.S. Laboratory module (08472); Logistics Module (08473); module layout (08474); Logistics Module and Experiment Module (08475).

Deep Generative Models of Galaxy Images for the Calibration of the Next Generation of Weak Lensing Surveys

NASA Astrophysics Data System (ADS)

Lanusse, Francois; Ravanbakhsh, Siamak; Mandelbaum, Rachel; Schneider, Jeff; Poczos, Barnabas

2017-01-01

Weak gravitational lensing has long been identified as one of the most powerful probes to investigate the nature of dark energy. As such, weak lensing is at the heart of the next generation of cosmological surveys such as LSST, Euclid or WFIRST.One particularly crititcal source of systematic errors in these surveys comes from the shape measurement algorithms tasked with estimating galaxy shapes. GREAT3, the last community challenge to assess the quality of state-of-the-art shape measurement algorithms has in particular demonstrated that all current methods are biased to various degrees and, more importantly, that these biases depend on the details of the galaxy morphologies. These biases can be measured and calibrated by generating mock observations where a known lensing signal has been introduced and comparing the resulting measurements to the ground-truth. Producing these mock observations however requires input galaxy images of higher resolution and S/N than the simulated survey, which typically implies acquiring extremely expensive space-based observations.The goal of this work is to train a deep generative model on already available Hubble Space Telescope data which can then be used to sample new galaxy images conditioned on parameters such as magnitude, size or redshift and exhibiting complex morphologies. Such model can allow us to inexpensively produce large set of realistic realistic images for calibration purposes.We implement a conditional generative model based on state-of-the-art deep learning methods and fit it to deep galaxy images from the COSMOS survey. The quality of the model is assessed by computing an extensive set of galaxy morphology statistics on the generated images. Beyond simple second moment statistics such as size and ellipticity, we apply more complex statistics specifically designed to be sensitive to disturbed galaxy morphologies. We find excellent agreement between the morphologies of real and model generated galaxies.Our results

VizieR Online Data Catalog: Nearby Seyfert galaxies FIR emissions (Garcia-Gonzalez+, 2016)

NASA Astrophysics Data System (ADS)

Garcia-Gonzalez, J.; Alonso-Herrero, A.; Hernan-Caballero, A.; Pereira-Santaella, M.; Ramos-Almeida, C.; Acosta-Pulido, J. A.; Diaz-Santos, T.; Esquej, P.; Gonzalez-Martin, O.; Ichikawa, K.; Lopez-Rodriguez, E.; Povic, M.; Roche, P. F.; Sanchez-Portal, M.

2017-06-01

We selected a sample of 33 nearby (distances DL<70Mpc, Table 1) Seyfert galaxies from the RSA catalogue (Sandage & Tammann 1987, Cat. VII/51) with Herschel/PACS imaging observations in at least two bands and SPIRE imaging observations from our own programmes and from the archive (see Table 3). (6 data files).

The outer halo globular cluster system of M31 - I. The final PAndAS catalogue

NASA Astrophysics Data System (ADS)

Huxor, A. P.; Mackey, A. D.; Ferguson, A. M. N.; Irwin, M. J.; Martin, N. F.; Tanvir, N. R.; Veljanoski, J.; McConnachie, A.; Fishlock, C. K.; Ibata, R.; Lewis, G. F.

2014-08-01

We report the discovery of 59 globular clusters (GCs) and two candidate GCs in a search of the halo of M31, primarily via visual inspection of Canada-France-Hawaii Telescope/MegaCam imagery from the Pan-Andromeda Archaeological Survey (PAndAS). The superior quality of these data also allows us to check the classification of remote objects in the Revised Bologna Catalogue (RBC), plus a subset of GC candidates drawn from Sloan Digital Sky Survey (SDSS) imaging. We identify three additional new GCs from the RBC, and confirm the GC nature of 11 SDSS objects (8 of which appear independently in our remote halo catalogue); the remaining 188 candidates across both lists are either foreground stars or background galaxies. Our new catalogue represents the first uniform census of GCs across the M31 halo - we find clusters to the limit of the PAndAS survey area at projected radii of up to Rproj ˜ 150 kpc. Tests using artificial clusters reveal that detection incompleteness cuts in at luminosities below MV = -6.0; our 50 per cent completeness limit is MV ≈ -4.1. We construct a uniform set of PAndAS photometric measurements for all known GCs outside Rproj = 25 kpc, and any new GCs within this radius. With these data, we update results from Huxor et al., investigating the luminosity function (LF), colours and effective radii of M31 GCs with a particular focus on the remote halo. We find that the GCLF is clearly bimodal in the outer halo (Rproj > 30 kpc), with the secondary peak at MV ˜ -5.5. We argue that the GCs in this peak have most likely been accreted along with their host dwarf galaxies. Notwithstanding, we also find, as in previous surveys, a substantial number of GCs with above-average luminosity in the outer M31 halo - a population with no clear counterpart in the Milky Way.

The HI Content of Galaxies as a Function of Local Density and Large-Scale Environment

NASA Astrophysics Data System (ADS)

Thoreen, Henry; Cantwell, Kelly; Maloney, Erin; Cane, Thomas; Brough Morris, Theodore; Flory, Oscar; Raskin, Mark; Crone-Odekon, Mary; ALFALFA Team

2017-01-01

We examine the HI content of galaxies as a function of environment, based on a catalogue of 41527 galaxies that are part of the 70% complete Arecibo Legacy Fast-ALFA (ALFALFA) survey. We use nearest-neighbor methods to characterize local environment, and a modified version of the algorithm developed for the Galaxy and Mass Assembly (GAMA) survey to classify large-scale environment as group, filament, tendril, or void. We compare the HI content in these environments using statistics that include both HI detections and the upper limits on detections from ALFALFA. The large size of the sample allows to statistically compare the HI content in different environments for early-type galaxies as well as late-type galaxies. This work is supported by NSF grants AST-1211005 and AST-1637339, the Skidmore Faculty-Student Summer Research program, and the Schupf Scholars program.

Mapping stellar content to dark matter haloes - III. Environmental dependence and conformity of galaxy colours

NASA Astrophysics Data System (ADS)

Zu, Ying; Mandelbaum, Rachel

2018-05-01

Recent studies suggest that the quenching properties of galaxies are correlated over several megaparsecs. The large-scale `galactic conformity' phenomenon around central galaxies has been regarded as a potential signature of `galaxy assembly bias' or `pre-heating', both of which interpret conformity as a result of direct environmental effects acting on galaxy formation. Building on the iHOD halo quenching framework developed in Zu and Mandelbaum, we discover that our fiducial halo mass quenching model, without any galaxy assembly bias, can successfully explain the overall environmental dependence and the conformity of galaxy colours in Sloan Digital Sky Survey, as measured by the mark correlation functions of galaxy colours and the red galaxy fractions around isolated primaries, respectively. Our fiducial iHOD halo quenching mock also correctly predicts the differences in the spatial clustering and galaxy-galaxy lensing signals between the more versus less red galaxy subsamples, split by the red-sequence ridge line at fixed stellar mass. Meanwhile, models that tie galaxy colours fully or partially to halo assembly bias have difficulties in matching all these observables simultaneously. Therefore, we demonstrate that the observed environmental dependence of galaxy colours can be naturally explained by the combination of (1) halo quenching and (2) the variation of halo mass function with environment - an indirect environmental effect mediated by two separate physical processes.

Galaxy Environment in the 3D-HST Fields: Witnessing the Onset of Satellite Quenching at z ˜ 1-2

NASA Astrophysics Data System (ADS)

Fossati, M.; Wilman, D. J.; Mendel, J. T.; Saglia, R. P.; Galametz, A.; Beifiori, A.; Bender, R.; Chan, J. C. C.; Fabricius, M.; Bandara, K.; Brammer, G. B.; Davies, R.; Förster Schreiber, N. M.; Genzel, R.; Hartley, W.; Kulkarni, S. K.; Lang, P.; Momcheva, I. G.; Nelson, E. J.; Skelton, R.; Tacconi, L. J.; Tadaki, K.; Übler, H.; van Dokkum, P. G.; Wisnioski, E.; Whitaker, K. E.; Wuyts, E.; Wuyts, S.

2017-02-01

We make publicly available a catalog of calibrated environmental measures for galaxies in the five 3D-Hubble Space Telescope (HST)/CANDELS deep fields. Leveraging the spectroscopic and grism redshifts from the 3D-HST survey, multiwavelength photometry from CANDELS, and wider field public data for edge corrections, we derive densities in fixed apertures to characterize the environment of galaxies brighter than {{JH}}140< 24 mag in the redshift range 0.5< z< 3.0. By linking observed galaxies to a mock sample, selected to reproduce the 3D-HST sample selection and redshift accuracy, each 3D-HST galaxy is assigned a probability density function of the host halo mass, and a probability that it is a central or a satellite galaxy. The same procedure is applied to a z = 0 sample selected from Sloan Digital Sky Survey. We compute the fraction of passive central and satellite galaxies as a function of stellar and halo mass, and redshift, and then derive the fraction of galaxies that were quenched by environment specific processes. Using the mock sample, we estimate that the timescale for satellite quenching is {t}{quench}˜ 2{--}5 {Gyr}; it is longer at lower stellar mass or lower redshift, but remarkably independent of halo mass. This indicates that, in the range of environments commonly found within the 3D-HST sample ({M}h≲ {10}14 {M}⊙ ), satellites are quenched by exhaustion of their gas reservoir in the absence of cosmological accretion. We find that the quenching times can be separated into a delay phase, during which satellite galaxies behave similarly to centrals at fixed stellar mass, and a phase where the star formation rate drops rapidly ({τ }f˜ 0.4{--}0.6 Gyr), as shown previously at z = 0. We conclude that this scenario requires satellite galaxies to retain a large reservoir of multi-phase gas upon accretion, even at high redshift, and that this gas sustains star formation for the long quenching times observed.

Detection of bars in galaxies using a deep convolutional neural network

NASA Astrophysics Data System (ADS)

Abraham, Sheelu; Aniyan, A. K.; Kembhavi, Ajit K.; Philip, N. S.; Vaghmare, Kaustubh

2018-06-01

We present an automated method for the detection of bar structure in optical images of galaxies using a deep convolutional neural network that is easy to use and provides good accuracy. In our study, we use a sample of 9346 galaxies in the redshift range of 0.009-0.2 from the Sloan Digital Sky Survey (SDSS), which has 3864 barred galaxies, the rest being unbarred. We reach a top precision of 94 per cent in identifying bars in galaxies using the trained network. This accuracy matches the accuracy reached by human experts on the same data without additional information about the images. Since deep convolutional neural networks can be scaled to handle large volumes of data, the method is expected to have great relevance in an era where astronomy data is rapidly increasing in terms of volume, variety, volatility, and velocity along with other V's that characterize big data. With the trained model, we have constructed a catalogue of barred galaxies from SDSS and made it available online.

Photometric Properties of Face-on Isolated Spiral Galaxies

NASA Astrophysics Data System (ADS)

Bahr, Alexander; Epstein, P.; Durbala, A.

2011-05-01

We want to quantify the relative role of nature versus nurture in defining the observed properties of galaxies. In simpler terms we would like to disentangle the ``genetic'’ and the environmental influences in shaping the morphology of galaxies. In order to do that one needs to firstly define a zero-order baseline, i.e., a sample of galaxies that have been minimally perturbed by neighbors in the last few billion years of their existence. Such a sample has been produced and refined in different stages in the context of the AMIGA international project (www.iaa.es/AMIGA.html). The recent catalogue ``The All-Sky Catalog of Isolated Galaxies Selected from 2MASS'’ (Karachentseva, V. E. et al. 2010) allows us to complete and enrich the initial sample constructed within AMIGA with new objects, thus enhancing the statistical relevance of our study. Our focus is to define a subset of isolated disk spiral galaxies. We constrain the sample selection by: 1) orientation, restricting to almost face-on galaxies and 2) availability of good photometric images in SDSS. The goal is to ``dissect'’ (decompose) these galaxies in major components (disk, bulge, bars, etc.) and to study the properties of the components in a statistical context. Having a reasonable representation of all morphological types, we aim to test the bimodality of bulges and bars. We present a progress report of our work.

General catalogue of variable stars: Version GCVS 5.1

NASA Astrophysics Data System (ADS)

Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N.

2017-01-01

Work aimed at compiling detailed catalogs of variable stars in the Galaxy, which has been carried out continuously by Moscow variable-star researchers since 1946 on behalf of the International Astronomical Union, has entered the stage of the publication of the 5th, completely electronic edition of the General Catalogue of Variable Stars (GCVS). This paper describes the requirements for the contents of the 5th edition and the current state of the catalog in its new version, GCVS 5.1. The complete revision of information for variable stars in the constellation Carina and the compilation of the 81st Name-list of Variable Stars are considered as examples of work on the 5th edition. The GCVS 5.1 is freely accessible on the Internet. We recommend the present paper as a unified reference to the 5th edition of the GCVS.

The galaxy environment in GAMA G3C groups using the Kilo Degree Survey Data Release 3

NASA Astrophysics Data System (ADS)

Costa-Duarte, M. V.; Viola, M.; Molino, A.; Kuijken, K.; , L. Sodré, Jr.; Bilicki, M.; Brouwer, M. M.; Buddelmeijer, H.; Grado, A.; de Jong, J. T. A.; Napolitano, N.; Puddu, E.; Radovich, M.; Vakili, M.

2018-04-01

We aim to investigate the galaxy environment in GAMA Galaxy Groups Catalogue (G3C) using a volume-limited galaxy sample from the Kilo Degree Survey Data Release 3. The k-Nearest Neighbour technique is adapted to take into account the probability density functions (PDFs) of photometric redshifts in our calculations. This algorithm was tested on simulated KiDS tiles, showing its capability of recovering the relation between galaxy colour, luminosity and local environment. The characterization of the galaxy environment in G3C groups shows systematically steeper density contrasts for more massive groups. The red galaxy fraction gradients in these groups is evident for most of group mass bins. The density contrast of red galaxies is systematically higher at group centers when compared to blue galaxy ones. In addition, distinct group center definitions are used to show that our results are insensitive to center definitions. These results confirm the galaxy evolution scenario which environmental mechanisms are responsible for a slow quenching process as galaxies fall into groups and clusters, resulting in a smooth observed colour gradients in galaxy systems.

Detection and Characterization of Galaxy Systems at Intermediate Redshift.

NASA Astrophysics Data System (ADS)

Barrena, Rafael

2004-11-01

This thesis is divided into two very related parts. In the first part we implement and apply a galaxy cluster detection method, based on multiband observations in visible. For this purpose, we use a new algorithm, the Voronoi Galaxy Cluster Finder, which identifies overdensities over a Poissonian field of objects. By applying this algorithm over four photometric bands (B, V, R and I) we reduce the possibility of detecting galaxy projection effects and spurious detections instead of real galaxy clusters. The B, V, R and I photometry allows a good characterization of galaxy systems. Therefore, we analyze the colour and early-type sequences in the colour-magnitude diagrams of the detected clusters. This analysis helps us to confirm the selected candidates as actual galaxy systems. In addition, by comparing observational early-type sequences with a semiempirical model we can estimate a photometric redshift for the detected clusters. We will apply this detection method on four 0.5x0.5 square degrees areas, that partially overlap the Postman Distant Cluster Survey (PDCS). The observations were performed as part of the International Time Programme 1999-B using the Wide Field Camera mounted at Isaac Newton Telescope (Roque de los Muchachos Observatory, La Palma island, Spain). The B and R data obtained were completed with V and I photometry performed by Marc Postman. The comparison of our cluster catalogue with that of PDCS reveals that our work is a clear improvement in the cluster detection techniques. Our method efficiently selects galaxy clusters, in particular low mass galaxy systems, even at relative high redshift, and estimate a precise photometric redshift. The validation of our method comes by observing spectroscopically several selected candidates. By comparing photometric and spectroscopic redshifts we conclude: 1) our photometric estimation method gives an precision lower than 0.1; 2) our detection technique is even able to detect galaxy systems at z~0.7 using

Determining accurate measurements of the growth rate from the galaxy correlation function in simulations

NASA Astrophysics Data System (ADS)

Contreras, Carlos; Blake, Chris; Poole, Gregory B.; Marin, Felipe

2013-04-01

We use high-resolution N-body simulations to develop a new, flexible empirical approach for measuring the growth rate from redshift-space distortions in the 2-point galaxy correlation function. We quantify the systematic error in measuring the growth rate in a 1 h-3 Gpc3 volume over a range of redshifts, from the dark matter particle distribution and a range of halo-mass catalogues with a number density comparable to the latest large-volume galaxy surveys such as the WiggleZ Dark Energy Survey and the Baryon Oscillation Spectroscopic Survey. Our simulations allow us to span halo masses with bias factors ranging from unity (probed by emission-line galaxies) to more massive haloes hosting luminous red galaxies. We show that the measured growth rate is sensitive to the model adopted for the small-scale real-space correlation function, and in particular that the `standard' assumption of a power-law correlation function can result in a significant systematic error in the growth-rate determination. We introduce a new, empirical fitting function that produces results with a lower (5-10 per cent) amplitude of systematic error. We also introduce a new technique which permits the galaxy pairwise velocity distribution, the quantity which drives the non-linear growth of structure, to be measured as a non-parametric stepwise function. Our (model-independent) results agree well with an exponential pairwise velocity distribution, expected from theoretical considerations, and are consistent with direct measurements of halo velocity differences from the parent catalogues. In a companion paper, we present the application of our new methodology to the WiggleZ Survey data set.

2dFLenS and KiDS: determining source redshift distributions with cross-correlations

NASA Astrophysics Data System (ADS)

Johnson, Andrew; Blake, Chris; Amon, Alexandra; Erben, Thomas; Glazebrook, Karl; Harnois-Deraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Joudaki, Shahab; Klaes, Dominik; Kuijken, Konrad; Lidman, Chris; Marin, Felipe A.; McFarland, John; Morrison, Christopher B.; Parkinson, David; Poole, Gregory B.; Radovich, Mario; Wolf, Christian

2017-03-01

We develop a statistical estimator to infer the redshift probability distribution of a photometric sample of galaxies from its angular cross-correlation in redshift bins with an overlapping spectroscopic sample. This estimator is a minimum-variance weighted quadratic function of the data: a quadratic estimator. This extends and modifies the methodology presented by McQuinn & White. The derived source redshift distribution is degenerate with the source galaxy bias, which must be constrained via additional assumptions. We apply this estimator to constrain source galaxy redshift distributions in the Kilo-Degree imaging survey through cross-correlation with the spectroscopic 2-degree Field Lensing Survey, presenting results first as a binned step-wise distribution in the range z < 0.8, and then building a continuous distribution using a Gaussian process model. We demonstrate the robustness of our methodology using mock catalogues constructed from N-body simulations, and comparisons with other techniques for inferring the redshift distribution.

On the Formation of Elliptical Galaxies via Mergers in Galaxy Groups

NASA Astrophysics Data System (ADS)

Taranu, Dan; Dubinski, John; Yee, Howard K. C.

2015-01-01

Giant elliptical galaxies have long been thought to form through gas-rich "major" mergers of two roughly equal-mass spiral galaxies. However, elliptical galaxies are often found at the centers of groups, and so are likely to have undergone several significant mergers. We test the hypothesis that ellipticals form through multiple, mainly minor and dry mergers in groups, using a novel sample of hundreds of N-body simulations of mergers in groups of three to twenty-five spiral galaxies.Realistic mock observations of the simulated central merger remnants show that they have comparable surface brightness profiles to observed ellipticals from SDSS and ATLAS3D - so long as the progenitor spirals begin with concentrated bulges. The remnants follow tight size-luminosity and velocity dispersion-luminosity relations (<0.12 dex scatter), with similar slopes as observed. Stochastic merging can produce tight scaling relations if the merging galaxies follow tight scaling relations themselves. However, the remnants are too large and have too low dispersions at fixed luminosity. Some remnants show substantial (v/σ > 0.1) rotational support, but most are slow rotators with v/σ << 0.5.Ellipticals also follow a tight "fundamental plane" scaling relation between size R, mean surface brightness μ and velocity dispersion σ: R ∝ σaμb, with small (<0.06 dex) scatter and significantly different coefficients from the expected scaling (a "tilt"). The remnants lie on a similar fundamental plane, with even smaller scatter (0.02 dex), as well as a tilt in the correct sense - albeit weaker than observed. This tilt is mainly driven by variable dark matter fractions within Reff, such that massive merger remnants have larger central dark matter fractions than their lower-mass counterparts.These results suggest that massive ellipticals can originate from multiple, mainly minor and dry mergers. However, significant gas dissipation may be needed to produce lower-mass, rapidly

The most massive galaxies in clusters are already fully grown at z ˜ 0.5

NASA Astrophysics Data System (ADS)

Oldham, L. J.; Houghton, R. C. W.; Davies, Roger L.

2017-02-01

By constructing scaling relations for galaxies in the massive cluster MACSJ0717.5 at z = 0.545 and comparing with those of Coma, we model the luminosity evolution of the stellar populations and the structural evolution of the galaxies. We calculate magnitudes, surface brightnesses and effective radii using Hubble Space Telescope (HST)/ACS images and velocity dispersions using Gemini/GMOS spectra, and present a catalogue of our measurements for 17 galaxies. We also generate photometric catalogues for ˜3000 galaxies from the HST imaging. With these, we construct the colour-magnitude relation, the Fundamental Plane, the mass-to-light versus mass relation, the mass-size relation and the mass-velocity dispersion relation for both clusters. We present a new, coherent way of modelling these scaling relations simultaneously using a simple physical model in order to infer the evolution in luminosity, size and velocity dispersion as a function of redshift, and show that the data can be fully accounted for with this model. We find that (a) the evolution in size and velocity dispersion undergone by these galaxies between z ˜ 0.5 and z ˜ 0 is mild, with Re(z) ˜ (1 + z)-0.40 ± 0.32 and σ(z) ˜ (1 + z)0.09 ± 0.27, and (b) the stellar populations are old, ˜10 Gyr, with a ˜3 Gyr dispersion in age, and are consistent with evolving purely passively since z ˜ 0.5 with Δ log M/L_B = -0.55_{-0.07}^{+0.15} z. The implication is that these galaxies formed their stars early and subsequently grew dissipationlessly so as to have their mass already in place by z ˜ 0.5, and suggests a dominant role for dry mergers, which may have accelerated the growth in these high-density cluster environments.

The KMOS Deep Survey: Dynamical Measurements of Star-Forming Galaxies at z 3.5

NASA Astrophysics Data System (ADS)

Turner, Owen; Cirasuolo, Michele; Harrison, Chris; McLure, Ross; Dunlop, James; Swinbank, Mark; Johnson, Helen; Sobral, David; Matthee, Jorryt; Sharples, Ray

2017-07-01

This poster present dynamical measurements from the KMOS (K-band Multi-Object Spectrograph) Deep Survey (KDS), which is comprised of 78 typical star-forming galaxies at z = 3.5 in the mass range 9.0 < log(M*) < 10.5. We fit spatially and spectrally convolved mock datacubes to the observed data, in order to make beam-smearing corrected measurements of the intrinsic velocity dispersions and rotation velocities of 33 galaxies in the sample classed as spatially resolved and isolated. The results suggest that the rotation-dominated galaxies in the sample are offset to lower velocities at fixed stellar mass and have higher velocity dispersions than star-forming galaxies in the local and intermediate redshift universe. Only 1/3 of the galaxies in the sample are dominated by rotation, which hints that random motions are playing an increasingly significant role in supporting the dynamical mass in the systems. When searching for evolution in scaling relations, such as the stellar mass Tully-Fisher relation, it is important to take these random motions into account.

Orbital decomposition of CALIFA spiral galaxies

NASA Astrophysics Data System (ADS)

Zhu, Ling; van den Bosch, Remco; van de Ven, Glenn; Lyubenova, Mariya; Falcón-Barroso, Jesús; Meidt, Sharon E.; Martig, Marie; Shen, Juntai; Li, Zhao-Yu; Yildirim, Akin; Walcher, C. Jakob; Sanchez, Sebastian F.

2018-01-01

Schwarzschild orbit-based dynamical models are widely used to uncover the internal dynamics of early-type galaxies and globular clusters. Here we present for the first time the Schwarzschild models of late-type galaxies: an SBb galaxy NGC 4210 and an S0 galaxy NGC 6278 from the Calar Alto Legacy Integral Field Area (CALIFA) survey. The mass profiles within 2Re are constrained well with 1σ statistical error of ∼ 10 per cent. The luminous and dark mass can be disentangled with uncertainties of ∼20 and ∼ 50 per cent, respectively. From Re to 2Re, the dark matter fraction increases from 14 ± 10 to 18 ± 10 per cent for NGC 4210 and from 15 ± 10 to 30 ± 20 per cent for NGC 6278. The velocity anisotropy profiles of both σr/σt and σz/σR are well constrained. The inferred internal orbital distributions reveal clear substructures. The orbits are naturally separated into three components: a cold component with near circular orbits; a hot component with near radial orbits and a warm component in between. The photometrically identified exponential discs are predominantly made up of cold orbits only beyond ∼1Re, while they are constructed mainly with the warm orbits inside. Our dynamical hot components are concentrated in the inner regions, similar to the photometrically identified bulges. The reliability of the results, especially the orbit distribution, is verified by applying the model to mock data.

A Detection Pipeline for Galactic Binaries in LISA Data

NASA Technical Reports Server (NTRS)

Littenberg, Tyson B.

2012-01-01

The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers) etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise - over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract greater than or equal to 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

A Galactic Binary Detection Pipeline

NASA Technical Reports Server (NTRS)

Littenberg, Tyson B.

2011-01-01

The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

Joint constraints on galaxy bias and σ{sub 8} through the N-pdf of the galaxy number density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arnalte-Mur, Pablo; Martínez, Vicent J.; Vielva, Patricio

We present a full description of the N-probability density function of the galaxy number density fluctuations. This N-pdf is given in terms, on the one hand, of the cold dark matter correlations and, on the other hand, of the galaxy bias parameter. The method relies on the assumption commonly adopted that the dark matter density fluctuations follow a local non-linear transformation of the initial energy density perturbations. The N-pdf of the galaxy number density fluctuations allows for an optimal estimation of the bias parameter (e.g., via maximum-likelihood estimation, or Bayesian inference if there exists any a priori information on themore » bias parameter), and of those parameters defining the dark matter correlations, in particular its amplitude (σ{sub 8}). It also provides the proper framework to perform model selection between two competitive hypotheses. The parameters estimation capabilities of the N-pdf are proved by SDSS-like simulations (both, ideal log-normal simulations and mocks obtained from Las Damas simulations), showing that our estimator is unbiased. We apply our formalism to the 7th release of the SDSS main sample (for a volume-limited subset with absolute magnitudes M{sub r} ≤ −20). We obtain b-circumflex  = 1.193 ± 0.074 and σ-bar{sub 8} = 0.862 ± 0.080, for galaxy number density fluctuations in cells of the size of 30h{sup −1}Mpc. Different model selection criteria show that galaxy biasing is clearly favoured.« less

Extending the ISC-GEM Global Earthquake Instrumental Catalogue

NASA Astrophysics Data System (ADS)

Di Giacomo, Domenico; Engdhal, Bob; Storchak, Dmitry; Villaseñor, Antonio; Harris, James

2015-04-01

After a 27-month project funded by the GEM Foundation (www.globalquakemodel.org), in January 2013 we released the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php) as a special product to use for seismic hazard studies. The new catalogue was necessary as improved seismic hazard studies necessitate that earthquake catalogues are homogeneous (to the largest extent possible) over time in their fundamental parameters, such as location and magnitude. Due to time and resource limitation, the ISC-GEM catalogue (1900-2009) included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 for earthquakes occurring before 1918; Ms=6.25 between 1918 and 1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from GEM and two commercial companies in the US and UK allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred beyond 2009 and for earthquakes listed in the International Seismological Summary (ISS) which fell below the cut-off magnitude of 6.25. This extension is part of a four-year program that aims at including in the ISC-GEM catalogue large global earthquakes that occurred before the beginning of the ISC Bulletin in 1964. In this contribution we present the updated ISC GEM catalogue, which will include over 1000 more earthquakes that occurred in 2010 2011 and several hundreds more between 1950 and 1959. The catalogue extension between 1935 and 1949 is currently underway. The extension of the ISC-GEM catalogue will also be helpful for regional cross border seismic hazard studies as the ISC-GEM catalogue should be used as basis for cross-checking the consistency in location and magnitude of those earthquakes listed both in the ISC GEM global catalogue and regional catalogues.

A Universe of ultradiffuse galaxies: theoretical predictions from ΛCDM simulations

NASA Astrophysics Data System (ADS)

Rong, Yu; Guo, Qi; Gao, Liang; Liao, Shihong; Xie, Lizhi; Puzia, Thomas H.; Sun, Shuangpeng; Pan, Jun

2017-10-01

A particular population of galaxies have drawn much interest recently, which are as faint as typical dwarf galaxies but have the sizes as large as L* galaxies, the so called ultradiffuse galaxies (UDGs). The lack of tidal features of UDGs in dense environments suggests that their host haloes are perhaps as massive as that of the Milky Way. On the other hand, galaxy formation efficiency should be much higher in the haloes of such masses. Here, we use the model galaxy catalogue generated by populating two large simulations: the Millennium-II cosmological simulation and Phoenix simulations of nine big clusters with the semi-analytic galaxy formation model. This model reproduces remarkably well the observed properties of UDGs in the nearby clusters, including the abundance, profile, colour and morphology, etc. We search for UDG candidates using the public data and find two UDG candidates in our Local Group and 23 in our Local Volume, in excellent agreement with the model predictions. We demonstrate that UDGs are genuine dwarf galaxies, formed in the haloes of ˜1010 M⊙. It is the combination of the late formation time and high spins of the host haloes that results in the spatially extended feature of this particular population. The lack of tidal disruption features of UDGs in clusters can also be explained by their late infall-time.

The influence of sex on mock jurors' verdicts across type of child abuse cases.

PubMed

Pettalia, Jennifer; Pozzulo, Joanna D; Reed, Jennifer

2017-07-01

This study examined the influence of victim sex, mock juror sex, and type of child abuse (physical, sexual, emotional, and neglect) on mock jurors' assessments of eyewitness and defendant integrity, continuous guilt ratings, dichotomous verdicts, and sentencing recommendations. Participants read one of eight versions of a trial transcript and then answered a self-report questionnaire. Female mock jurors were significantly more likely to find the defendant guilty overall. Moreover, female mock jurors recommended significantly longer sentences for defendants in sexual abuse cases; whereas, male mock jurors recommended significantly longer sentences for defendants in sexual and physical abuse cases. Male mock jurors perceived the defendant more favorably than female mock jurors; whereas, female mock jurors perceived the alleged victim more favorable than male mock jurors. These results suggest that juror sex may be an influential factor in child abuse cases overall. Copyright © 2017 Elsevier Ltd. All rights reserved.

VizieR Online Data Catalog: XMM-Newton point-source catalogue of the SMC (Sturm+, 2013)

NASA Astrophysics Data System (ADS)

Sturm, R.; Haberl, F.; Pietsch, W.; Ballet, J.; Hatzidimitriou, D.; Buckley, D. A. H.; Coe, M.; Ehle, M.; Filipovic, M. D.; La Palombara, N.; Tiengo, A.

2013-07-01

The XMM-Newton survey of the Small Magellanic Cloud (SMC) yields a complete coverage of the bar and eastern wing in the 0.2-12.0keV band. This catalogue comprises 3053 unique X-ray point sources and sources with moderate extent that have been reduced from 5236 individual detections found in observations between April 2000 and April 2010. Sources have a median position uncertainty of 1.3" (1σ) and limiting fluxes down to ~1*10-14erg/s/cm2 in the 0.2-4.5keV band, corresponding to 5*1033erg/s for sources in the SMC. Sources have been classified using hardness ratios, X-ray variability, and their multi-wavelength properties. In addition to the main-field (5.58deg2) available outer fields have been included in the catalogue, yielding a total field area of 6.32deg2. X-ray sources with high extent (>40", e.g. supernova remnants and galaxy cluster) have been presented by Haberl et al. (2012, Cat. J/A+A/545/A128) (2 data files).

The Impact of Assembly Bias on the Galaxy Content of Dark Matter Halos

NASA Astrophysics Data System (ADS)

Zehavi, Idit; Contreras, Sergio; Padilla, Nelson; Smith, Nicholas J.; Baugh, Carlton M.; Norberg, Peder

2018-01-01

We study the dependence of the galaxy content of dark matter halos on large-scale environment and halo formation time using semi-analytic galaxy models applied to the Millennium simulation. We analyze subsamples of halos at the extremes of these distributions and measure the occupation functions for the galaxies they host. We find distinct differences among these occupation functions. The main effect with environment is that central galaxies (and in one model, also the satellites) in denser regions start populating lower-mass halos. A similar, but significantly stronger, trend exists with halo age, where early-forming halos are more likely to host central galaxies at lower halo mass. We discuss the origin of these trends and the connection to the stellar mass–halo mass relation. We find that, at fixed halo mass, older halos and to some extent also halos in dense environments tend to host more massive galaxies. Additionally, we see a reverse trend for the occupation of satellite galaxies where early-forming halos have fewer satellites, likely due to having more time for them to merge with the central galaxy. We describe these occupancy variations in terms of the changes in the occupation function parameters, which can aid in constructing realistic mock galaxy samples. Finally, we study the corresponding galaxy auto- and cross-correlation functions of the different samples and elucidate the impact of assembly bias on galaxy clustering. Our results can inform theoretical modeling of galaxy assembly bias and attempts to detect it in the real universe.

The dependence of halo mass on galaxy size at fixed stellar mass using weak lensing

NASA Astrophysics Data System (ADS)

Charlton, Paul J. L.; Hudson, Michael J.; Balogh, Michael L.; Khatri, Sumeet

2017-12-01

Stellar mass has been shown to correlate with halo mass, with non-negligible scatter. The stellar mass-size and luminosity-size relationships of galaxies also show significant scatter in galaxy size at fixed stellar mass. It is possible that, at fixed stellar mass and galaxy colour, the halo mass is correlated with galaxy size. Galaxy-galaxy lensing allows us to measure the mean masses of dark matter haloes for stacked samples of galaxies. We extend the analysis of the galaxies in the CFHTLenS catalogue by fitting single Sérsic surface brightness profiles to the lens galaxies in order to recover half-light radius values, allowing us to determine halo masses for lenses according to their size. Comparing our halo masses and sizes to baselines for that stellar mass yields a differential measurement of the halo mass-galaxy size relationship at fixed stellar mass, defined as Mh(M_{*}) ∝ r_{eff}^{η }(M_{*}). We find that, on average, our lens galaxies have an η = 0.42 ± 0.12, i.e. larger galaxies live in more massive dark matter haloes. The η is strongest for high-mass luminous red galaxies. Investigation of this relationship in hydrodynamical simulations suggests that, at a fixed M*, satellite galaxies have a larger η and greater scatter in the Mh and reff relationship compared to central galaxies.

IDEOS: Fitting Infrared Spectra from Dusty Galaxies

NASA Astrophysics Data System (ADS)

Viola, Vincent; Rupke, D.

2014-01-01

We fit models to heavily obscured infrared spectra taken by the Spitzer Space Telescope and prepare them for cataloguing in the Infrared Database of Extragalactic Observables from Spitzer (IDEOS). When completed, IDEOS will contain homogeneously measured mid-infrared spectroscopic observables of more than 4200 galaxies beyond the Local Group. The software we use, QUESTFit, models the spectra using up to three extincted blackbodies (including silicate, water ice, and hydrocarbon absorption) and PAH templates. We present results from a sample of the approximately 200 heavily obscured spectra that will be present in IDEOS.

CATPAC -- Catalogue Applications Package on UNIX

NASA Astrophysics Data System (ADS)

Wood, A. R.

CATPAC is the STARLINK Catalogue and Table Package. This document describes the CATPAC applications available on UNIX. These include applications for inputing, processing and reporting tabular data including astronomical catalogues.

Improving fast generation of halo catalogues with higher order Lagrangian perturbation theory

NASA Astrophysics Data System (ADS)

Munari, Emiliano; Monaco, Pierluigi; Sefusatti, Emiliano; Castorina, Emanuele; Mohammad, Faizan G.; Anselmi, Stefano; Borgani, Stefano

2017-03-01

We present the latest version of PINOCCHIO, a code that generates catalogues of dark matter haloes in an approximate but fast way with respect to an N-body simulation. This code version implements a new on-the-fly production of halo catalogue on the past light cone with continuous time sampling, and the computation of particle and halo displacements are extended up to third-order Lagrangian perturbation theory (LPT), in contrast with previous versions that used Zel'dovich approximation. We run PINOCCHIO on the same initial configuration of a reference N-body simulation, so that the comparison extends to the object-by-object level. We consider haloes at redshifts 0 and 1, using different LPT orders either for halo construction or to compute halo final positions. We compare the clustering properties of PINOCCHIO haloes with those from the simulation by computing the power spectrum and two-point correlation function in real and redshift space (monopole and quadrupole), the bispectrum and the phase difference of halo distributions. We find that 2LPT and 3LPT give noticeable improvement. 3LPT provides the best agreement with N-body when it is used to displace haloes, while 2LPT gives better results for constructing haloes. At the highest orders, linear bias is typically recovered at a few per cent level. In Fourier space and using 3LPT for halo displacements, the halo power spectrum is recovered to within 10 per cent up to kmax ∼ 0.5 h Mpc-1. The results presented in this paper have interesting implications for the generation of large ensemble of mock surveys for the scientific exploitation of data from big surveys.

Radio Identifications of UGC Galaxies - Starbursts and Monsters

NASA Astrophysics Data System (ADS)

Condon, J. J.; Broderick, J. J.

1995-11-01

Radio identifications of galaxies in the Uppsala General Catalogue of Galaxies with delta < +82 degrees were made from the Green Bank 1400 MHz sky maps. Every source having peak flux density S(P) >= 150 mJy in the approximately 12 arcmin FWHM map point-source response and position < 5 arcmin in both coordinates from the optical position of any UGC galaxy was considered a candidate identification to ensure that very extended (up to 1 Mpc) and asymmetric sources would not be missed. Maps in the literature or new 1.49 GHz VLA C-array maps made with 18 arcsec FWHM resolution were used to confirm or reject candidate identifications. The maps in this directory include both confirmed identifications and candidates rejected because of confusion or low flux density. For more information on this study, please see the following reference: Condon, J. J., and Broderick, J. J., 1988, AJ, 96, 30. The images and related TeX file come from the NRAO CDROM "Images From the Radio Universe" (c. 1992 National Radio Astronomy Observatory, used with permission).

Galaxy clusters in simulations of the local Universe: a matter of constraints

NASA Astrophysics Data System (ADS)

Sorce, Jenny G.; Tempel, Elmo

2018-06-01

To study the full formation and evolution history of galaxy clusters and their population, high-resolution simulations of the latter are flourishing. However, comparing observed clusters to the simulated ones on a one-to-one basis to refine the models and theories down to the details is non-trivial. The large variety of clusters limits the comparisons between observed and numerical clusters. Simulations resembling the local Universe down to the cluster scales permit pushing the limit. Simulated and observed clusters can be matched on a one-to-one basis for direct comparisons provided that clusters are well reproduced besides being in the proper large-scale environment. Comparing random and local Universe-like simulations obtained with differently grouped observational catalogues of peculiar velocities, this paper shows that the grouping scheme used to remove non-linear motions in the catalogues that constrain the simulations affects the quality of the numerical clusters. With a less aggressive grouping scheme - galaxies still falling on to clusters are preserved - combined with a bias minimization scheme, the mass of the dark matter haloes, simulacra for five local clusters - Virgo, Centaurus, Coma, Hydra, and Perseus - is increased by 39 per cent closing the gap with observational mass estimates. Simulacra are found on average in 89 per cent of the simulations, an increase of 5 per cent with respect to the previous grouping scheme. The only exception is Perseus. Since the Perseus-Pisces region is not well covered by the used peculiar velocity catalogue, the latest release lets us foresee a better simulacrum for Perseus in a near future.

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

DOE PAGES

Beutler, Florian; Seo, Hee -Jong; Ross, Ashley J.; ...

2016-07-13

Here, we analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes 1 198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this dataset into three (overlapping) redshift bins with the effective redshifts z eff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as 1000 MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density eld reconstruction to enhancemore » the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can sep-arate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance D A(z) and the Hubble parameter H ( z ) separately. We obtain two independent 1 : 6% and 1 : 5% constraints on D A(z) and 2.9% and 2.3% constraints on H(z) for the low (z eff = 0.38) and high (z eff = 0.61) redshift bin, respectively. We obtain two independent 1% and 0.9% constraints on the angular averaged distance D V(z), when ignoring the Alcock-Paczynski e ect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.« less

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beutler, Florian; Seo, Hee -Jong; Ross, Ashley J.

Here, we analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes 1 198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this dataset into three (overlapping) redshift bins with the effective redshifts z eff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as 1000 MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density eld reconstruction to enhancemore » the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can sep-arate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance D A(z) and the Hubble parameter H ( z ) separately. We obtain two independent 1 : 6% and 1 : 5% constraints on D A(z) and 2.9% and 2.3% constraints on H(z) for the low (z eff = 0.38) and high (z eff = 0.61) redshift bin, respectively. We obtain two independent 1% and 0.9% constraints on the angular averaged distance D V(z), when ignoring the Alcock-Paczynski e ect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.« less

Using Controversial Mock Trials in "Psychology and Law" Courses: Suggestions from Participants.

ERIC Educational Resources Information Center

Werth, James L., Jr.; Harvey, James; McNamara, Rebecca; Svoboda, Andrea; Gulbrandson, Raina; Hendren, Jennifer; Greedy, Tiffany; Leybold, Christie

2002-01-01

Describes a mock trial focused on Jack Kevorkian and an euthanasia case that was included in a psychology and law course. Discusses the course format, provides the reactions to the mock trial by students and consultants, and includes suggestions for improving the mock trial. (CMK)

Mock climate summit: teaching and assessing learning

NASA Astrophysics Data System (ADS)

Schweizer, D.; Gautier, C.; Bazerman, C.

2003-04-01

This paper will demonstrate the effectiveness of a Mock Climate Summit as a pedagogical approach for teaching the science and policy aspects of global climate change. The Mock Climate Summit is a student-centered course simulating the Conference of the Parties (COP) where international environmental protocols are negotiated. Compared to traditional lecture-based methods common in the geoscience classroom, the Mock Climate Summit uses negotiations and arguments to teach the interactions between these two “spheres” and demonstrate the depth and breadth of these interactions. Through a detailed assessment of students’ dialogue transcribed from video and audio tapes, we found that the nature of the student dialogue matures rapidly as they are given multiple opportunities to present, negotiate and argue a specific topic. Students’ dialogue progress from hypothetical (what-if) scenarios to action-oriented scenarios and implementation plans. The progression of the students’ dialogue shows increased comfort with the communities’ discourse as they take ownership of the point-of-view associated with their assumed roles.

Mock Climate Summit: Teaching and Assessing Learning

NASA Astrophysics Data System (ADS)

Schweizer, D.; Gautier, C.; Bazerman, C.

2003-04-01

This paper will demonstrate the effectiveness of a Mock Climate Summit as a pedagogical for teaching the science and policy aspects of global climate change. The Mock Climate Summit is a student-centered course simulating the Conference of the Parties (COP) where international environmental protocols are negotiated. Compared to traditional lecture-based methods common in the geoscience classroom, the Mock Climate Summit uses negotiations and arguments to teach the interactions between these two "spheres" and demonstrate the depth and breadth of these interactions. Through a detailed assessment of students' dialogue transcribed from video and audio tapes, we found that the nature of the student dialogue matures rapidly as they are given multiple opportunities to present, negotiate and argue a specific topic. Students' dialogue progress from hypothetical (what-if) scenarios to action-oriented scenarios and implementation plans. The progression of the students' dialogue shows increased comfort with the communities' discourse as they take ownership of the point-of-view associated with their assumed roles.

Cold Gas in Quenched Dwarf Galaxies using HI-MaNGA

NASA Astrophysics Data System (ADS)

Bonilla, Alaina

2017-01-01

MaNGA (Mapping of Nearby Galaxies at Apache Point Observatory) is a 6-year Sloan Digital Sky Survey fourth generation (SDSS-IV) project that will obtain integral field spectroscopy of a catalogue of 10,000 nearby galaxies. In this study, we explore the properties of the passive dwarf galaxy sample presented in Penny et al. 2016, making use of MaNGA IFU (Integral Field Unit) data to plot gas emission, stellar velocity, and flux maps. In addition, HI-MaNGA, a legacy radio-survey of MaNGA, collects single dish HI data retrieved from the GBT (Green Bank Telescope), which we use to study the the 21cm emission lines present in HI detections. Studying the HI content of passive dwarves will help us reveal the processes that are preventing star formation, such as possible AGN feedback. This work was supported by the SDSS Research Experience for Undergraduates program, which is funded by a grant from the Sloan Foundation to the Astrophysical Research Consortium.

Guidelines for Cataloguing-in-Publication.

ERIC Educational Resources Information Center

Anderson, Dorothy, Comp.

The guidelines provide the criteria for the design of a national cataloguing-in-publication (CIP) program which will both be a component part of the international CIP network and fit the requirements of a specific library and publishing environment. Cataloguing-in-publication is defined, its development is traced, and current CIP programs in nine…

The Mock Research Paper

ERIC Educational Resources Information Center

Clark, Carlton

2008-01-01

The mock research paper combines creative writing with academic writing and, in the process, breaks down that binary. This article describes a writing assignment that offers an introduction to the college research paper genre. This assignment helps students focus on crafting an argument and learning genre conventions while postponing until the…

LOFAR 150-MHz observations of the Boötes field: catalogue and source counts

NASA Astrophysics Data System (ADS)

Williams, W. L.; van Weeren, R. J.; Röttgering, H. J. A.; Best, P.; Dijkema, T. J.; de Gasperin, F.; Hardcastle, M. J.; Heald, G.; Prandoni, I.; Sabater, J.; Shimwell, T. W.; Tasse, C.; van Bemmel, I. M.; Brüggen, M.; Brunetti, G.; Conway, J. E.; Enßlin, T.; Engels, D.; Falcke, H.; Ferrari, C.; Haverkorn, M.; Jackson, N.; Jarvis, M. J.; Kapińska, A. D.; Mahony, E. K.; Miley, G. K.; Morabito, L. K.; Morganti, R.; Orrú, E.; Retana-Montenegro, E.; Sridhar, S. S.; Toribio, M. C.; White, G. J.; Wise, M. W.; Zwart, J. T. L.

2016-08-01

We present the first wide area (19 deg2), deep (≈120-150 μJy beam-1), high-resolution (5.6 × 7.4 arcsec) LOFAR High Band Antenna image of the Boötes field made at 130-169 MHz. This image is at least an order of magnitude deeper and 3-5 times higher in angular resolution than previously achieved for this field at low frequencies. The observations and data reduction, which includes full direction-dependent calibration, are described here. We present a radio source catalogue containing 6 276 sources detected over an area of 19 deg2, with a peak flux density threshold of 5σ. As the first thorough test of the facet calibration strategy, introduced by van Weeren et al., we investigate the flux and positional accuracy of the catalogue. We present differential source counts that reach an order of magnitude deeper in flux density than previously achieved at these low frequencies, and show flattening at 150-MHz flux densities below 10 mJy associated with the rise of the low flux density star-forming galaxies and radio-quiet AGN.

The AKARI FU-HYU galaxy evolution program: first results from the GOODS-N field

NASA Astrophysics Data System (ADS)

Pearson, C. P.; Serjeant, S.; Negrello, M.; Takagi, T.; Jeong, W.-S.; Matsuhara, H.; Wada, T.; Oyabu, S.; Lee, H. M.; Im, M. S.

2010-05-01

The AKARI FU-HYU mission program carried out mid-infrared imaging of several well studied Spitzer fields preferentially selecting fields already rich in multi-wavelength data from radio to X-ray wavelengths filling in the wavelength desert between the Spitzer IRAC and MIPS bands. We present the initial results for the FU-HYU survey in the GOODS-N field. We utilize the supreme multiwavelength coverage in the GOODS-N field to produce a multiwavelength catalogue from infrared to ultraviolet wavelengths, containing more than 4393 sources, including photometric redshifts. Using the FU-HYU catalogue we present colour-colour diagrams that map the passage of PAH features through our observation bands. We find that the longer mid-infrared bands from AKARI (IRC-L18W 18 micron band) and Spitzer (MIPS24 24 micron band) provide an accurate measure of the total MIR emission of the sources and therefore their probable total mid-infrared luminosity. We also find that colours incorporating the AKARI IRC-S11 11 micron band produce a bimodal distribution where an excess at 11 microns preferentially selects moderate redshift star-forming galaxies. These powerful colour-colour diagnostics are further used as tools to extract anomalous colour populations, in particular a population of Silicate Break galaxies from the GOODS-N field showing that dusty starbursts can be selected of specific redshift ranges (z = 1.2-1.6) by mid-infrared drop-out techniques. The FU-HYU catalogue will be made publically available to the astronomical community.

Towards a library of synthetic galaxy spectra and preliminary results of classification and parametrization of unresolved galaxies for Gaia. II

NASA Astrophysics Data System (ADS)

Tsalmantza, P.; Kontizas, M.; Rocca-Volmerange, B.; Bailer-Jones, C. A. L.; Kontizas, E.; Bellas-Velidis, I.; Livanou, E.; Korakitis, R.; Dapergolas, A.; Vallenari, A.; Fioc, M.

2009-09-01

Aims: This paper is the second in a series, implementing a classification system for Gaia observations of unresolved galaxies. Our goals are to determine spectral classes and estimate intrinsic astrophysical parameters via synthetic templates. Here we describe (1) a new extended library of synthetic galaxy spectra; (2) its comparison with various observations; and (3) first results of classification and parametrization experiments using simulated Gaia spectrophotometry of this library. Methods: Using the PÉGASE.2 code, based on galaxy evolution models that take account of metallicity evolution, extinction correction, and emission lines (with stellar spectra based on the BaSeL library), we improved our first library and extended it to cover the domain of most of the SDSS catalogue. Our classification and regression models were support vector machines (SVMs). Results: We produce an extended library of 28 885 synthetic galaxy spectra at zero redshift covering four general Hubble types of galaxies, over the wavelength range between 250 and 1050 nm at a sampling of 1 nm or less. The library is also produced for 4 random values of redshift in the range of 0-0.2. It is computed on a random grid of four key astrophysical parameters (infall timescale and 3 parameters defining the SFR) and, depending on the galaxy type, on two values of the age of the galaxy. The synthetic library was compared and found to be in good agreement with various observations. The first results from the SVM classifiers and parametrizers are promising, indicating that Hubble types can be reliably predicted and several parameters estimated with low bias and variance.

The Planck Catalogue of Galactic Cold Clumps : Looking at the early stages of star-formation

NASA Astrophysics Data System (ADS)

Montier, Ludovic

2015-08-01

The Planck satellite has provided an unprecedented view of the submm sky, allowing us to search for the dust emission of Galactic cold sources. Combining Planck-HFI all-sky maps in the high frequency channels with the IRAS map at 100um, we built the Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015), counting 13188 sources distributed over the whole sky, and following mainly the Galactic structures at low and intermediate latitudes. This is the first all-sky catalogue of Galactic cold sources obtained with a single instrument at this resolution and sensitivity, which opens a new window on star-formation processes in our Galaxy.I will briefly describe the colour detection method used to extract the Galactic cold sources, i.e., the Cold Core Colour Detection Tool (CoCoCoDeT, Montier et al. 2010), and its application to the Planck data. I will discuss the statistical distribution of the properties of the PGCC sources (in terms of dust temperature, distance, mass, density and luminosity), which illustrates that the PGCC catalogue spans a large variety of environments and objects, from molecular clouds to cold cores, and covers various stages of evolution. The Planck catalogue is a very powerful tool to study the formation and the evolution of prestellar objects and star-forming regions.I will finally present an overview of the Herschel Key Program Galactic Cold Cores (PI. M.Juvela), which allowed us to follow-up about 350 Planck Galactic Cold Clumps, in various stages of evolution and environments. With this program, the nature and the composition of the 5' Planck sources have been revealed at a sub-arcmin resolution, showing very different configurations, such as starless cold cores or multiple Young Stellar objects still embedded in their cold envelope.

AGB and post-AGB objects in the outer Galaxy

NASA Astrophysics Data System (ADS)

Szczerba, Ryszard; Yung, Bosco H. K.; Sewiło, Marta; Siódmiak, Natasza; Karska, Agata

2017-10-01

We present the results of our search for low- and intermediate mass evolved stars in the outer Galaxy using AllWISE catalogue photometry. We show that the [3.4]-[12] vs. [4.6]-[22] colour-colour diagram is most suitable for separating C-rich/O-rich AGB and post-AGB star candidates. We are able to select 2,510 AGB and 24,821 post-AGB star candidates. However, the latter are severely mixed with the known young stellar objects in this diagram.

OmegaWINGS: OmegaCAM-VST observations of WINGS galaxy clusters

NASA Astrophysics Data System (ADS)

Gullieuszik, M.; Poggianti, B.; Fasano, G.; Zaggia, S.; Paccagnella, A.; Moretti, A.; Bettoni, D.; D'Onofrio, M.; Couch, W. J.; Vulcani, B.; Fritz, J.; Omizzolo, A.; Baruffolo, A.; Schipani, P.; Capaccioli, M.; Varela, J.

2015-09-01

Context. Wide-field observations targeting galaxy clusters at low redshift are complementary to field surveys and provide the local benchmark for detailed studies of the most massive haloes in the local Universe. The Wide-field Nearby Galaxy-cluster Survey (WINGS) is a wide-field multi-wavelength survey of X-ray selected clusters at z = 0.04-0.07. The original 34' × 34' WINGS field of view has now been extended to cover a 1 deg2 field with both photometry and spectroscopy. Aims: We present the Johnson B- and V-band OmegaCAM at the VST observations of 46 WINGS clusters together with the data reduction, data quality, and Sextractor photometric catalogues. Methods: The data reduction was carried out with a modified version of the ESO-MVM (also known as ALAMBIC) reduction package, adding a cross-talk correction, the gain harmonisation, and a control procedure for problematic CCDs. The stray-light component was corrected for by employing our own observations of populated stellar fields. Results: With a median seeing of 1″ in both bands, our 25-min exposures in each band typically reach the 50% completeness level at V = 23.1 mag. The quality of the astrometric and photometric accuracy has been verified by comparison with the 2MASS and SDSS astrometry, and SDSS and previous WINGS imaging. Star-to-galaxy separation and sky-subtraction procedure were tested comparing them with previous WINGS data. Conclusions: The Sextractor photometric catalogues are publicly available at the CDS and will be included in the next release of the WINGS database on the Virtual Observatory together with the OmegaCAM reduced images. These data form the basis for a large ongoing spectroscopic campaign with AAOmega at the AAT and are being employed for a variety of studies. Based on observations made with VST at ESO Paranal Observatory under program ID 88.A-4005, 089.A-0023, 090.A-0074, 091.A-0059, and 093.A-0041.The photometric catalogue is only available at the CDS via anonymous ftp to http

Alcohol promotions in Australian supermarket catalogues.

PubMed

Johnston, Robyn; Stafford, Julia; Pierce, Hannah; Daube, Mike

2017-07-01

In Australia, most alcohol is sold as packaged liquor from off-premises retailers, a market increasingly dominated by supermarket chains. Competition between retailers may encourage marketing approaches, for example, discounting, that evidence indicates contribute to alcohol-related harms. This research documented the nature and variety of promotional methods used by two major supermarket retailers to promote alcohol products in their supermarket catalogues. Weekly catalogues from the two largest Australian supermarket chains were reviewed for alcohol-related content over 12 months. Alcohol promotions were assessed for promotion type, product type, number of standard drinks, purchase price and price/standard drink. Each store catalogue included, on average, 13 alcohol promotions/week, with price-based promotions most common. Forty-five percent of promotions required the purchase of multiple alcohol items. Wine was the most frequently promoted product (44%), followed by beer (24%) and spirits (18%). Most (99%) wine cask (2-5 L container) promotions required multiple (two to three) casks to be purchased. The average number of standard drinks required to be purchased to participate in catalogue promotions was 31.7 (SD = 24.9; median = 23.1). The median price per standard drink was $1.49 (range $0.19-$9.81). Cask wines had the lowest cost per standard drink across all product types. Supermarket catalogues' emphasis on low prices/high volumes of alcohol reflects that retailers are taking advantage of limited restrictions on off-premise sales and promotion, which allow them to approach market competition in ways that may increase alcohol-related harms in consumers. Regulation of alcohol marketing should address retailer catalogue promotions. [Johnston R, Stafford J, Pierce H, Daube M. Alcohol promotions in Australian supermarket catalogues. Drug Alcohol Rev 2017;36:456-463]. © 2016 Australasian Professional Society on Alcohol and other Drugs.

Ultraviolet and optical view of galaxies in the Coma Supercluster

NASA Astrophysics Data System (ADS)

Mahajan, Smriti; Singh, Ankit; Shobhana, Devika

2018-05-01

The Coma supercluster (100h-1Mpc) offers an unprecedented contiguous range of environments in the nearby Universe. In this paper we present a catalogue of spectroscopically confirmed galaxies in the Coma supercluster detected in the ultraviolet (UV) wavebands. We use the arsenal of UV and optical data for galaxies in the Coma supercluster covering ˜500 square degrees on the sky to study their photometric and spectroscopic properties as a function of environment at various scales. We identify the different components of the cosmic-web: large-scale filaments and voids using Discrete Persistent Structures Extractor, and groups and clusters using Hierarchical Density-based spatial clustering of applications with noise, respectively. We find that in the Coma supercluster the median emission in Hα inclines, while the g - r and FUV - NUV colours of galaxies become bluer moving further away from the spine of the filaments out to a radius of ˜1 Mpc. On the other hand, an opposite trend is observed as the distance between the galaxy and centre of the nearest cluster or group decreases. Our analysis supports the hypothesis that properties of galaxies are not just defined by its stellar mass and large-scale density, but also by the environmental processes resulting due to the intrafilament medium whose role in accelerating galaxy transformations needs to be investigated thoroughly using multi-wavelength data.

The ASAS-SN bright supernova catalogue – I. 2013–2014

DOE PAGES

Holoien, T. W. -S.; Stanek, K. Z.; Kochanek, C. S.; ...

2016-09-12

We present basic statistics for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during its first year-and-a-half of operations, spanning 2013 and 2014. We also present the same information for all other bright (m V ≤ 17), spectroscopically confirmed supernovae discovered from 2014 May 1 through the end of 2014, providing a comparison to the ASAS-SN sample starting from the point where ASAS-SN became operational in both hemispheres. In addition, we present collected redshifts and near-UV through IR magnitudes, where available, for all host galaxies of the bright supernovae in both samples. This work represents a comprehensivemore » catalogue of bright supernovae and their hosts from multiple professional and amateur sources, allowing for population studies that were not previously possible because the all-sky emphasis of ASAS-SN redresses many previously existing biases. In particular, ASAS-SN systematically finds bright supernovae closer to the centres of host galaxies than either other professional surveys or amateurs, a remarkable result given ASAS-SN's poorer angular resolution. In conclusion, this is the first of a series of yearly papers on bright supernovae and their hosts that will be released by the ASAS-SN team.« less

Mapping extragalactic dark matter annihilation with galaxy surveys: A systematic study of stacked group searches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lisanti, Mariangela; Mishra-Sharma, Siddharth; Rodd, Nicholas L.

Dark matter in the halos surrounding galaxy groups and clusters can annihilate to high-energy photons. Recent advancements in the construction of galaxy group catalogs provide many thousands of potential extragalactic targets for dark matter. In this paper, we outline a procedure to infer the dark matter signal associated with a given galaxy group. Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe (z≲0.03), supplementing sources of dark matter annihilation from within the local group. As with searches for dark matter in dwarf galaxies, thesemore » extragalactic targets can be stacked together to enhance the signals associated with dark matter. We validate this procedure on mock Fermi gamma-ray data sets using a galaxy catalog constructed from the DarkSky N-body cosmological simulation and demonstrate that the limits are robust, at O(1) levels, to systematic uncertainties on halo mass and concentration. We also quantify other sources of systematic uncertainty arising from the analysis and modeling assumptions. Lastly, our results suggest that a stacking analysis using galaxy group catalogs provides a powerful opportunity to discover extragalactic dark matter and complements existing studies of Milky Way dwarf galaxies.« less

Mapping extragalactic dark matter annihilation with galaxy surveys: A systematic study of stacked group searches

NASA Astrophysics Data System (ADS)

Lisanti, Mariangela; Mishra-Sharma, Siddharth; Rodd, Nicholas L.; Safdi, Benjamin R.; Wechsler, Risa H.

2018-03-01

Dark matter in the halos surrounding galaxy groups and clusters can annihilate to high-energy photons. Recent advancements in the construction of galaxy group catalogs provide many thousands of potential extragalactic targets for dark matter. In this paper, we outline a procedure to infer the dark matter signal associated with a given galaxy group. Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe (z ≲0.03 ), supplementing sources of dark matter annihilation from within the local group. As with searches for dark matter in dwarf galaxies, these extragalactic targets can be stacked together to enhance the signals associated with dark matter. We validate this procedure on mock Fermi gamma-ray data sets using a galaxy catalog constructed from the DarkSky N -body cosmological simulation and demonstrate that the limits are robust, at O (1 ) levels, to systematic uncertainties on halo mass and concentration. We also quantify other sources of systematic uncertainty arising from the analysis and modeling assumptions. Our results suggest that a stacking analysis using galaxy group catalogs provides a powerful opportunity to discover extragalactic dark matter and complements existing studies of Milky Way dwarf galaxies.

Mapping extragalactic dark matter annihilation with galaxy surveys: A systematic study of stacked group searches

DOE PAGES

Lisanti, Mariangela; Mishra-Sharma, Siddharth; Rodd, Nicholas L.; ...

2018-03-09

Dark matter in the halos surrounding galaxy groups and clusters can annihilate to high-energy photons. Recent advancements in the construction of galaxy group catalogs provide many thousands of potential extragalactic targets for dark matter. In this paper, we outline a procedure to infer the dark matter signal associated with a given galaxy group. Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe (z≲0.03), supplementing sources of dark matter annihilation from within the local group. As with searches for dark matter in dwarf galaxies, thesemore » extragalactic targets can be stacked together to enhance the signals associated with dark matter. We validate this procedure on mock Fermi gamma-ray data sets using a galaxy catalog constructed from the DarkSky N-body cosmological simulation and demonstrate that the limits are robust, at O(1) levels, to systematic uncertainties on halo mass and concentration. We also quantify other sources of systematic uncertainty arising from the analysis and modeling assumptions. Lastly, our results suggest that a stacking analysis using galaxy group catalogs provides a powerful opportunity to discover extragalactic dark matter and complements existing studies of Milky Way dwarf galaxies.« less

FRBCAT: The Fast Radio Burst Catalogue

NASA Astrophysics Data System (ADS)

Petroff, E.; Barr, E. D.; Jameson, A.; Keane, E. F.; Bailes, M.; Kramer, M.; Morello, V.; Tabbara, D.; van Straten, W.

2016-09-01

Here, we present a catalogue of known Fast Radio Burst sources in the form of an online catalogue, FRBCAT. The catalogue includes information about the instrumentation used for the observations for each detected burst, the measured quantities from each observation, and model-dependent quantities derived from observed quantities. To aid in consistent comparisons of burst properties such as width and signal-to-noise ratios, we have re-processed all the bursts for which we have access to the raw data, with software which we make available. The originally derived properties are also listed for comparison. The catalogue is hosted online as a Mysql database which can also be downloaded in tabular or plain text format for off-line use. This database will be maintained for use by the community for studies of the Fast Radio Burst population as it grows.

Can neutrino decay-driven mock gravity save hot dark matter?

NASA Technical Reports Server (NTRS)

Splinter, Randall J.; Melott, Adrian L.

1992-01-01

The radiative decay of a 30 eV neutrino with a lifetime of order 10 exp 23-24 s has recently been shown to yield a satisfactory explanation of a wide range of problems in astrophysics. In this paper, it is investigated whether the photon flux generated by the radiative decay of a massive neutrino is capable of generating sufficient radiation pressure to cause a 'mock gravitational' collapse of primordial hydrogen clouds. It is shown that when using neutral hydrogen as a source of opacity for mock gravity the time scale for mock gravitational collapse is significantly larger than the expansion time scale. Thus, the model fails as a source of galactic seed perturbations. Furthermore, it is argued that nonlinear feedback mechanisms will be unable to increase the collapse rate of the cloud under mock gravity.

A large sample of Kohonen selected E+A (post-starburst) galaxies from the Sloan Digital Sky Survey

NASA Astrophysics Data System (ADS)

Meusinger, H.; Brünecke, J.; Schalldach, P.; in der Au, A.

2017-01-01

Context. The galaxy population in the contemporary Universe is characterised by a clear bimodality, blue galaxies with significant ongoing star formation and red galaxies with only a little. The migration between the blue and the red cloud of galaxies is an issue of active research. Post starburst (PSB) galaxies are thought to be observed in the short-lived transition phase. Aims: We aim to create a large sample of local PSB galaxies from the Sloan Digital Sky Survey (SDSS) to study their characteristic properties, particularly morphological features indicative of gravitational distortions and indications for active galactic nuclei (AGNs). Another aim is to present a tool set for an efficient search in a large database of SDSS spectra based on Kohonen self-organising maps (SOMs). Methods: We computed a huge Kohonen SOM for ∼106 spectra from SDSS data release 7. The SOM is made fully available, in combination with an interactive user interface, for the astronomical community. We selected a large sample of PSB galaxies taking advantage of the clustering behaviour of the SOM. The morphologies of both PSB galaxies and randomly selected galaxies from a comparison sample in SDSS Stripe 82 (S82) were inspected on deep co-added SDSS images to search for indications of gravitational distortions. We used the Portsmouth galaxy property computations to study the evolutionary stage of the PSB galaxies and archival multi-wavelength data to search for hidden AGNs. Results: We compiled a catalogue of 2665 PSB galaxies with redshifts z < 0.4, among them 74 galaxies in S82 with EW(Hδ) > 3 Å and z < 0.25. In the colour-mass diagram, the PSB sample is clearly concentrated towards the region between the red and the blue cloud, in agreement with the idea that PSB galaxies represent the transitioning phase between actively and passively evolving galaxies. The relative frequency of distorted PSB galaxies is at least 57% for EW(Hδ) > 5 Å, significantly higher than in the comparison

BioCatalogue: a universal catalogue of web services for the life sciences.

PubMed

Bhagat, Jiten; Tanoh, Franck; Nzuobontane, Eric; Laurent, Thomas; Orlowski, Jerzy; Roos, Marco; Wolstencroft, Katy; Aleksejevs, Sergejs; Stevens, Robert; Pettifer, Steve; Lopez, Rodrigo; Goble, Carole A

2010-07-01

The use of Web Services to enable programmatic access to on-line bioinformatics is becoming increasingly important in the Life Sciences. However, their number, distribution and the variable quality of their documentation can make their discovery and subsequent use difficult. A Web Services registry with information on available services will help to bring together service providers and their users. The BioCatalogue (http://www.biocatalogue.org/) provides a common interface for registering, browsing and annotating Web Services to the Life Science community. Services in the BioCatalogue can be described and searched in multiple ways based upon their technical types, bioinformatics categories, user tags, service providers or data inputs and outputs. They are also subject to constant monitoring, allowing the identification of service problems and changes and the filtering-out of unavailable or unreliable resources. The system is accessible via a human-readable 'Web 2.0'-style interface and a programmatic Web Service interface. The BioCatalogue follows a community approach in which all services can be registered, browsed and incrementally documented with annotations by any member of the scientific community.

Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments

DOE PAGES

Takahashi, Ryuichi; Hamana, Takashi; Shirasaki, Masato; ...

2017-11-14

We present 108 full-sky gravitational lensing simulation data sets generated by performing multiple-lens plane ray-tracing through high-resolution cosmological N-body simulations. The data sets include full-sky convergence and shear maps from redshifts z = 0.05 to 5.3 at intervals ofmore » $$150\\,{h}^{-1}\\mathrm{Mpc}$$ comoving radial distance (corresponding to a redshift interval of $${\\rm{\\Delta }}z\\simeq 0.05$$ at the nearby universe), enabling the construction of a mock shear catalog for an arbitrary source distribution up to z = 5.3. The dark matter halos are identified from the same N-body simulations with enough mass resolution to resolve the host halos of the Sloan Digital Sky Survey (SDSS) CMASS and luminous red galaxies (LRGs). Angular positions and redshifts of the halos are provided by a ray-tracing calculation, enabling the creation of a mock halo catalog to be used for galaxy–galaxy and cluster–galaxy lensing. The simulation also yields maps of gravitational lensing deflections for a source redshift at the last scattering surface, and we provide 108 realizations of lensed cosmic microwave background (CMB) maps in which the post-Born corrections caused by multiple light scattering are included. We present basic statistics of the simulation data, including the angular power spectra of cosmic shear, CMB temperature and polarization anisotropies, galaxy–galaxy lensing signals for halos, and their covariances. The angular power spectra of the cosmic shear and CMB anisotropies agree with theoretical predictions within 5% up to $${\\ell }=3000$$ (or at an angular scale $$\\theta \\gt 0.5$$ arcmin). The simulation data sets are generated primarily for the ongoing Subaru Hyper Suprime-Cam survey, but are freely available for download at http://cosmo.phys.hirosaki-u.ac.jp/takahasi/allsky_raytracing/.« less

Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Ryuichi; Hamana, Takashi; Shirasaki, Masato

We present 108 full-sky gravitational lensing simulation data sets generated by performing multiple-lens plane ray-tracing through high-resolution cosmological N-body simulations. The data sets include full-sky convergence and shear maps from redshifts z = 0.05 to 5.3 at intervals ofmore » $$150\\,{h}^{-1}\\mathrm{Mpc}$$ comoving radial distance (corresponding to a redshift interval of $${\\rm{\\Delta }}z\\simeq 0.05$$ at the nearby universe), enabling the construction of a mock shear catalog for an arbitrary source distribution up to z = 5.3. The dark matter halos are identified from the same N-body simulations with enough mass resolution to resolve the host halos of the Sloan Digital Sky Survey (SDSS) CMASS and luminous red galaxies (LRGs). Angular positions and redshifts of the halos are provided by a ray-tracing calculation, enabling the creation of a mock halo catalog to be used for galaxy–galaxy and cluster–galaxy lensing. The simulation also yields maps of gravitational lensing deflections for a source redshift at the last scattering surface, and we provide 108 realizations of lensed cosmic microwave background (CMB) maps in which the post-Born corrections caused by multiple light scattering are included. We present basic statistics of the simulation data, including the angular power spectra of cosmic shear, CMB temperature and polarization anisotropies, galaxy–galaxy lensing signals for halos, and their covariances. The angular power spectra of the cosmic shear and CMB anisotropies agree with theoretical predictions within 5% up to $${\\ell }=3000$$ (or at an angular scale $$\\theta \\gt 0.5$$ arcmin). The simulation data sets are generated primarily for the ongoing Subaru Hyper Suprime-Cam survey, but are freely available for download at http://cosmo.phys.hirosaki-u.ac.jp/takahasi/allsky_raytracing/.« less

Probabilistic multi-catalogue positional cross-match

NASA Astrophysics Data System (ADS)

Pineau, F.-X.; Derriere, S.; Motch, C.; Carrera, F. J.; Genova, F.; Michel, L.; Mingo, B.; Mints, A.; Nebot Gómez-Morán, A.; Rosen, S. R.; Ruiz Camuñas, A.

2017-01-01

Context. Catalogue cross-correlation is essential to building large sets of multi-wavelength data, whether it be to study the properties of populations of astrophysical objects or to build reference catalogues (or timeseries) from survey observations. Nevertheless, resorting to automated processes with limited sets of information available on large numbers of sources detected at different epochs with various filters and instruments inevitably leads to spurious associations. We need both statistical criteria to select detections to be merged as unique sources, and statistical indicators helping in achieving compromises between completeness and reliability of selected associations. Aims: We lay the foundations of a statistical framework for multi-catalogue cross-correlation and cross-identification based on explicit simplified catalogue models. A proper identification process should rely on both astrometric and photometric data. Under some conditions, the astrometric part and the photometric part can be processed separately and merged a posteriori to provide a single global probability of identification. The present paper addresses almost exclusively the astrometrical part and specifies the proper probabilities to be merged with photometric likelihoods. Methods: To select matching candidates in n catalogues, we used the Chi (or, indifferently, the Chi-square) test with 2(n-1) degrees of freedom. We thus call this cross-match a χ-match. In order to use Bayes' formula, we considered exhaustive sets of hypotheses based on combinatorial analysis. The volume of the χ-test domain of acceptance - a 2(n-1)-dimensional acceptance ellipsoid - is used to estimate the expected numbers of spurious associations. We derived priors for those numbers using a frequentist approach relying on simple geometrical considerations. Likelihoods are based on standard Rayleigh, χ and Poisson distributions that we normalized over the χ-test acceptance domain. We validated our theoretical

Submillimeter, millimeter, and microwave spectral line catalogue

NASA Technical Reports Server (NTRS)

Poynter, R. L.; Pickett, H. M.

1984-01-01

This report describes a computer accessible catalogue of submillimeter, millimeter, and microwave spectral lines in the frequency range between 0 and 10000 GHz (i.e., wavelengths longer than 30 micrometers). The catalogue can be used as a planning guide or as an aid in the identification and analysis of observed spectral lines. The information listed for each spectral line includes the frequency and its estimated error, the intensity, lower state energy, and quantum number assignment. The catalogue has been constructed using theoretical least squares fits of published spectral lines to accepted molecular models. The associated predictions and their estimated errors are based upon the resultant fitted parameters and their covariances. Future versions of this catalogue will add more atoms and molecules and update the present listings (151 species) as new data appear. The catalogue is available from the authors as a magnetic tape recorded in card images and as a set of microfiche records.

CCD photometry of Andromeda IV - Dwarf irregular galaxy or M31 open cluster?

NASA Technical Reports Server (NTRS)

Jones, Joseph H.

1993-01-01

CCD photometry of Andromeda IV was obtained during discretionary time in August of 1989 at the Canada-France-Hawaii Telescope on Mauna Kea and the data were reduced at CFHT during the summer of 1991. And IV has been catalogued both as a dwarf galaxy and as an open star cluster in M31. The color-magnitude diagrams presented indicate that this object has a young population of stars with a narrow age range, consistent with the characteristics of an open star cluster or stellar association. A radial velocity measurement taken from the literature and analyzed with respect to the rotation curve of M31 indicates this object resides in the disk of the Andromeda Galaxy, strengthening the conclusion that it is indeed a very large open star cluster or a densely populated stellar association rather than a dwarf irregular galaxy.

Galaxy pairs in the Sloan Digital Sky Survey - VII. The merger-luminous infrared galaxy connection

NASA Astrophysics Data System (ADS)

Ellison, Sara L.; Mendel, J. Trevor; Scudder, Jillian M.; Patton, David R.; Palmer, Michael J. D.

2013-04-01

We use a sample of 9397 low-redshift (z ≤ 0.1) galaxies with a close companion to investigate the connection between mergers and luminous infrared (IR) galaxies (LIRGs). The pairs are selected from the Sloan Digital Sky Survey (SDSS) and have projected separations rp ≤ 80 h{^{- 1}_{70}} kpc, relative velocities ΔV ≤ 300 km s-1 and stellar mass ratios within a factor of 1:10. A control sample consisting of four galaxies per pair galaxy is constructed by simultaneously matching in stellar mass, redshift and environment to galaxies with no close companion. The IR luminosities (LIR) of galaxies in the pair and control samples are determined from the SDSS - Infrared Astronomical Satellite (IRAS) matched catalogue of Hwang et al. Over the redshift range of our pairs sample, the IRAS matches are complete to LIRG luminosities (LIR ≥ 1011 L⊙), allowing us to investigate the connection between mergers and luminous IR galaxies. We find a trend for increasing LIRG fraction towards smaller pair separations, peaking at a factor of ˜5-10 above the median control fraction at the smallest separations (rp < 20 h{^{- 1}_{70}} kpc), but remaining elevated by a factor ˜2-3 even out to 80 h{^{- 1}_{70}} kpc (the widest separations in our sample). LIRG pairs predominantly have high star formation rates (SFRs), high extinction and are found in relatively low-density environments, relative to the full pairs sample. We also find that LIRGs are most likely to be found in high-mass galaxies which have an approximately equal-mass companion. We confirm the results of previous studies that both the active galactic nucleus (AGN) fraction and merger fraction increase strongly as a function of IR luminosity. About 7 per cent of LIRGs are associated with major mergers, as defined within the criteria and mass completion of our sample. Finally, we quantify an SFR offset (ΔSFR) as the enhancement (or decrement) relative to star-forming galaxies of the same mass and redshift. We

An All-Sky Portable (ASP) Optical Catalogue

NASA Astrophysics Data System (ADS)

Flesch, Eric Wim

2017-06-01

This optical catalogue combines the all-sky USNO-B1.0/A1.0 and most-sky APM catalogues, plus overlays of SDSS optical data, into a single all-sky map presented in a sparse binary format that is easily downloaded at 9 Gb zipped. Total count is 1 163 237 190 sources and each has J2000 astrometry, red and blue magnitudes with PSFs and variability indicator, and flags for proper motion, epoch, and source survey and catalogue for each of the photometry and astrometry. The catalogue is available on http://quasars.org/asp.html, and additional data for this paper is available at http://dx.doi.org/10.4225/50/5807fbc12595f.

The Herschel-ATLAS data release 1 - I. Maps, catalogues and number counts

NASA Astrophysics Data System (ADS)

Valiante, E.; Smith, M. W. L.; Eales, S.; Maddox, S. J.; Ibar, E.; Hopwood, R.; Dunne, L.; Cigan, P. J.; Dye, S.; Pascale, E.; Rigby, E. E.; Bourne, N.; Furlanetto, C.; Ivison, R. J.

2016-11-01

We present the first major data release of the largest single key-project in area carried out in open time with the Herschel Space Observatory. The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 600 deg2 in five photometric bands - 100, 160, 250, 350 and 500 μm - with the Photoconductor Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver (SPIRE) cameras. In this paper and the companion Paper II, we present the survey of three fields on the celestial equator, covering a total area of 161.6 deg2 and previously observed in the Galaxy and Mass Assembly (GAMA) spectroscopic survey. This paper describes the Herschel images and catalogues of the sources detected on the SPIRE 250 μm images. The 1σ noise for source detection, including both confusion and instrumental noise, is 7.4, 9.4 and 10.2 mJy at 250, 350 and 500 μm. Our catalogue includes 120 230 sources in total, with 113 995, 46 209 and 11 011 sources detected at >4σ at 250, 350 and 500 μm. The catalogue contains detections at >3σ at 100 and 160 μm for 4650 and 5685 sources, and the typical noise at these wavelengths is 44 and 49 mJy. We include estimates of the completeness of the survey and of the effects of flux bias and also describe a novel method for determining the true source counts. The H-ATLAS source counts are very similar to the source counts from the deeper HerMES survey at 250 and 350 μm, with a small difference at 500 μm. Appendix A provides a quick start in using the released data sets, including instructions and cautions on how to use them.

MACS J0416.1-2403: Impact of line-of-sight structures on strong gravitational lensing modelling of galaxy clusters

NASA Astrophysics Data System (ADS)

Chirivì, G.; Suyu, S. H.; Grillo, C.; Halkola, A.; Balestra, I.; Caminha, G. B.; Mercurio, A.; Rosati, P.

2018-06-01

Exploiting the powerful tool of strong gravitational lensing by galaxy clusters to study the highest-redshift Universe and cluster mass distributions relies on precise lens mass modelling. In this work, we aim to present the first attempt at modelling line-of-sight (LOS) mass distribution in addition to that of the cluster, extending previous modelling techniques that assume mass distributions to be on a single lens plane. We have focussed on the Hubble Frontier Field cluster MACS J0416.1-2403, and our multi-plane model reproduces the observed image positions with a rms offset of 0.''53. Starting from this best-fitting model, we simulated a mock cluster that resembles MACS J0416.1-2403 in order to explore the effects of LOS structures on cluster mass modelling. By systematically analysing the mock cluster under different model assumptions, we find that neglecting the lensing environment has a significant impact on the reconstruction of image positions (rms 0.''3); accounting for LOS galaxies as if they were at the cluster redshift can partially reduce this offset. Moreover, foreground galaxies are more important to include into the model than the background ones. While the magnification factor of the lensed multiple images are recovered within 10% for 95% of them, those 5% that lie near critical curves can be significantly affected by the exclusion of the lensing environment in the models. In addition, LOS galaxies cannot explain the apparent discrepancy in the properties of massive sub-halos between MACS J0416.1-2403 and N-body simulated clusters. Since our model of MACS J0416.1-2403 with LOS galaxies only reduced modestly the rms offset in the image positions, we conclude that additional complexities would be needed in future models of MACS J0416.1-2403.

Topology in two dimensions. II - The Abell and ACO cluster catalogues

NASA Astrophysics Data System (ADS)

Plionis, Manolis; Valdarnini, Riccardo; Coles, Peter

1992-09-01

We apply a method for quantifying the topology of projected galaxy clustering to the Abell and ACO catalogues of rich clusters. We use numerical simulations to quantify the statistical bias involved in using high peaks to define the large-scale structure, and we use the results obtained to correct our observational determinations for this known selection effect and also for possible errors introduced by boundary effects. We find that the Abell cluster sample is consistent with clusters being identified with high peaks of a Gaussian random field, but that the ACO shows a slight meatball shift away from the Gaussian behavior over and above that expected purely from the high-peak selection. The most conservative explanation of this effect is that it is caused by some artefact of the procedure used to select the clusters in the two samples.

VizieR Online Data Catalog: Sombrero galaxy globular clusters (Alves-Brito+, 2011)

NASA Astrophysics Data System (ADS)

Alves-Brito, A.; Hau, G. K. T.; Forbes, D. A.; Spitler, L. R.; Strader, J.; Brodie, J. P.; Rhode, K. L.

2018-01-01

GC candidates were selected from two published photometric studies. In the inner regions we used the BVR Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) mosaic of Spitler et al. (2006, Cat. J/AJ/132/1593), which covers approximately the central 10x7-arcmin2 of the galaxy with minimal contamination. Beyond this area, we used the ground-based BVR catalogue of Rhode & Zepf (2004AJ....127..302R). This latter catalogue has higher contamination but extends to the apparent edge of the GC system at a projected radius of 19 arcmin and so is necessary to complement the wide field of view (16x5arcmin2) of the DEIMOS spectrograph. The central dust lane of NGC 4594 was excluded from our target selection. (2 data files).

Mock ECHO: A Simulation-Based Medical Education Method.

PubMed

Fowler, Rebecca C; Katzman, Joanna G; Comerci, George D; Shelley, Brian M; Duhigg, Daniel; Olivas, Cynthia; Arnold, Thomas; Kalishman, Summers; Monnette, Rebecca; Arora, Sanjeev

2018-04-16

This study was designed to develop a deeper understanding of the learning and social processes that take place during the simulation-based medical education for practicing providers as part of the Project ECHO® model, known as Mock ECHO training. The ECHO model is utilized to expand access to care of common and complex diseases by supporting the education of primary care providers with an interprofessional team of specialists via videoconferencing networks. Mock ECHO trainings are conducted through a train the trainer model targeted at leaders replicating the ECHO model at their organizations. Trainers conduct simulated teleECHO clinics while participants gain skills to improve communication and self-efficacy. Three focus groups, conducted between May 2015 and January 2016 with a total of 26 participants, were deductively analyzed to identify common themes related to simulation-based medical education and interdisciplinary education. Principal themes generated from the analysis included (a) the role of empathy in community development, (b) the value of training tools as guides for learning, (c) Mock ECHO design components to optimize learning, (d) the role of interdisciplinary education to build community and improve care delivery, (e) improving care integration through collaboration, and (f) development of soft skills to facilitate learning. Mock ECHO trainings offer clinicians the freedom to learn in a noncritical environment while emphasizing real-time multidirectional feedback and encouraging knowledge and skill transfer. The success of the ECHO model depends on training interprofessional healthcare providers in behaviors needed to lead a teleECHO clinic and to collaborate in the educational process. While building a community of practice, Mock ECHO provides a safe opportunity for a diverse group of clinician experts to practice learned skills and receive feedback from coparticipants and facilitators.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.

We develop empirical methods for modeling the galaxy population and populating cosmological N-body simulations with mock galaxies according to the observed properties of galaxies in survey data. We use these techniques to produce a new set of mock catalogs for the DEEP2 Galaxy Redshift Survey based on the output of the high-resolution Bolshoi simulation, as well as two other simulations with different cosmological parameters, all of which we release for public use. The mock-catalog creation technique uses subhalo abundance matching to assign galaxy luminosities to simulated dark-matter halos. It then adds color information to the resulting mock galaxies in amore » manner that depends on the local galaxy density, in order to reproduce the measured color-environment relation in the data. In the course of constructing the catalogs, we test various models for including scatter in the relation between halo mass and galaxy luminosity, within the abundance-matching framework. We find that there is no constant-scatter model that can simultaneously reproduce both the luminosity function and the autocorrelation function of DEEP2. This result has implications for galaxy-formation theory, and it restricts the range of contexts in which the mock catalogs can be usefully applied. Nevertheless, careful comparisons show that our new mock catalogs accurately reproduce a wide range of the other properties of the DEEP2 catalog, suggesting that they can be used to gain a detailed understanding of various selection effects in DEEP2.« less

Estimating precise metallicity and stellar mass evolution of galaxies

NASA Astrophysics Data System (ADS)

Mosby, Gregory

2018-01-01

The evolution of galaxies can be conveniently broken down into the evolution of their contents. The changing dust, gas, and stellar content in addition to the changing dark matter potential and periodic feedback from a super-massive blackhole are some of the key ingredients. We focus on the stellar content that can be observed, as the stars reflect information about the galaxy when they were formed. We approximate the stellar content and star formation histories of unresolved galaxies using stellar population modeling. Though simplistic, this approach allows us to reconstruct the star formation histories of galaxies that can be used to test models of galaxy formation and evolution. These models, however, suffer from degeneracies at large lookback times (t > 1 Gyr) as red, low luminosity stars begin to dominate a galaxy’s spectrum. Additionally, degeneracies between stellar populations at different ages and metallicities often make stellar population modeling less precise. The machine learning technique diffusion k-means has been shown to increase the precision in stellar population modeling using a mono-metallicity basis set. However, as galaxies evolve, we expect the metallicity of stellar populations to vary. We use diffusion k-means to generate a multi-metallicity basis set to estimate the stellar mass and chemical evolution of unresolved galaxies. Two basis sets are formed from the Bruzual & Charlot 2003 and MILES stellar population models. We then compare the accuracy and precision of these models in recovering complete (stellar mass and metallicity) histories of mock data. Similarities in the groupings of stellar population spectra in the diffusion maps for each metallicity hint at fundamental age transitions common to both basis sets that can be used to identify stellar populations in a given age range.

Merged infrared catalogue

NASA Technical Reports Server (NTRS)

Schmitz, M.; Brown, L. W.; Mead, J. M.; Nagy, T. A.

1978-01-01

A compilation of equatorial coordinates, spectral types, magnitudes, and fluxes from five catalogues of infrared observations is presented. This first edition of the Merged Infrared Catalogue contains 11,201 oservations from the Two-Micron Sky Survey, Observations of Infrared Radiation from Cool Stars, the Air Force Geophysics Laboratory four Color Infrared Sky Survey and its Supplemental Catalog, and from Catalog of 10 micron Celestial Objects (HALL). This compilation is a by-product of a computerized infrared data base under development at Goddard Space Flight Center; the objective is to maintain a complete and current record of all infrared observations from 1 micron m to 1000 micron m of nonsolar system objects. These observations are being placed into a standardized system.

Grid computing enhances standards-compatible geospatial catalogue service

NASA Astrophysics Data System (ADS)

Chen, Aijun; Di, Liping; Bai, Yuqi; Wei, Yaxing; Liu, Yang

2010-04-01

A catalogue service facilitates sharing, discovery, retrieval, management of, and access to large volumes of distributed geospatial resources, for example data, services, applications, and their replicas on the Internet. Grid computing provides an infrastructure for effective use of computing, storage, and other resources available online. The Open Geospatial Consortium has proposed a catalogue service specification and a series of profiles for promoting the interoperability of geospatial resources. By referring to the profile of the catalogue service for Web, an innovative information model of a catalogue service is proposed to offer Grid-enabled registry, management, retrieval of and access to geospatial resources and their replicas. This information model extends the e-business registry information model by adopting several geospatial data and service metadata standards—the International Organization for Standardization (ISO)'s 19115/19119 standards and the US Federal Geographic Data Committee (FGDC) and US National Aeronautics and Space Administration (NASA) metadata standards for describing and indexing geospatial resources. In order to select the optimal geospatial resources and their replicas managed by the Grid, the Grid data management service and information service from the Globus Toolkits are closely integrated with the extended catalogue information model. Based on this new model, a catalogue service is implemented first as a Web service. Then, the catalogue service is further developed as a Grid service conforming to Grid service specifications. The catalogue service can be deployed in both the Web and Grid environments and accessed by standard Web services or authorized Grid services, respectively. The catalogue service has been implemented at the George Mason University/Center for Spatial Information Science and Systems (GMU/CSISS), managing more than 17 TB of geospatial data and geospatial Grid services. This service makes it easy to share and

New Generation of Catalogues for the New Generation of Users: A Comparison of Six Library Catalogues

ERIC Educational Resources Information Center

Mercun, Tanja; Zumer, Maja

2008-01-01

Purpose: The purpose of this paper is to describe some of the problems and issues faced by online library catalogues. It aims to establish how libraries have undertaken the mission of developing the next generation catalogues and how they compare to new tools such as Amazon. Design/methodology/approach: An expert study was carried out in January…

Gas kinematics in FIRE simulated galaxies compared to spatially unresolved H I observations

NASA Astrophysics Data System (ADS)

El-Badry, Kareem; Bradford, Jeremy; Quataert, Eliot; Geha, Marla; Boylan-Kolchin, Michael; Weisz, Daniel R.; Wetzel, Andrew; Hopkins, Philip F.; Chan, T. K.; Fitts, Alex; Kereš, Dušan; Faucher-Giguère, Claude-André

2018-06-01

The shape of a galaxy's spatially unresolved, globally integrated 21-cm emission line depends on its internal gas kinematics: galaxies with rotationally supported gas discs produce double-horned profiles with steep wings, while galaxies with dispersion-supported gas produce Gaussian-like profiles with sloped wings. Using mock observations of simulated galaxies from the FIRE project, we show that one can therefore constrain a galaxy's gas kinematics from its unresolved 21-cm line profile. In particular, we find that the kurtosis of the 21-cm line increases with decreasing V/σ and that this trend is robust across a wide range of masses, signal-to-noise ratios, and inclinations. We then quantify the shapes of 21-cm line profiles from a morphologically unbiased sample of ˜2000 low-redshift, H I-detected galaxies with Mstar = 107-11 M⊙ and compare to the simulated galaxies. At Mstar ≳ 1010 M⊙, both the observed and simulated galaxies produce double-horned profiles with low kurtosis and steep wings, consistent with rotationally supported discs. Both the observed and simulated line profiles become more Gaussian like (higher kurtosis and less-steep wings) at lower masses, indicating increased dispersion support. However, the simulated galaxies transition from rotational to dispersion support more strongly: at Mstar = 108-10 M⊙, most of the simulations produce more Gaussian-like profiles than typical observed galaxies with similar mass, indicating that gas in the low-mass simulated galaxies is, on average, overly dispersion supported. Most of the lower-mass-simulated galaxies also have somewhat lower gas fractions than the median of the observed population. The simulations nevertheless reproduce the observed line-width baryonic Tully-Fisher relation, which is insensitive to rotational versus dispersion support.

BioCatalogue: a universal catalogue of web services for the life sciences

PubMed Central

Bhagat, Jiten; Tanoh, Franck; Nzuobontane, Eric; Laurent, Thomas; Orlowski, Jerzy; Roos, Marco; Wolstencroft, Katy; Aleksejevs, Sergejs; Stevens, Robert; Pettifer, Steve; Lopez, Rodrigo; Goble, Carole A.

2010-01-01

The use of Web Services to enable programmatic access to on-line bioinformatics is becoming increasingly important in the Life Sciences. However, their number, distribution and the variable quality of their documentation can make their discovery and subsequent use difficult. A Web Services registry with information on available services will help to bring together service providers and their users. The BioCatalogue (http://www.biocatalogue.org/) provides a common interface for registering, browsing and annotating Web Services to the Life Science community. Services in the BioCatalogue can be described and searched in multiple ways based upon their technical types, bioinformatics categories, user tags, service providers or data inputs and outputs. They are also subject to constant monitoring, allowing the identification of service problems and changes and the filtering-out of unavailable or unreliable resources. The system is accessible via a human-readable ‘Web 2.0’-style interface and a programmatic Web Service interface. The BioCatalogue follows a community approach in which all services can be registered, browsed and incrementally documented with annotations by any member of the scientific community. PMID:20484378

Data Release of UV to Submillimeter Broadband Fluxes for Simulated Galaxies from the EAGLE Project

NASA Astrophysics Data System (ADS)

Camps, Peter; Trčka, Ana; Trayford, James; Baes, Maarten; Theuns, Tom; Crain, Robert A.; McAlpine, Stuart; Schaller, Matthieu; Schaye, Joop

2018-02-01

We present dust-attenuated and dust emission fluxes for sufficiently resolved galaxies in the EAGLE suite of cosmological hydrodynamical simulations, calculated with the SKIRT radiative transfer code. The post-processing procedure includes specific components for star formation regions, stellar sources, and diffuse dust and takes into account stochastic heating of dust grains to obtain realistic broadband fluxes in the wavelength range from ultraviolet to submillimeter. The mock survey includes nearly half a million simulated galaxies with stellar masses above {10}8.5 {M}ȯ across six EAGLE models. About two-thirds of these galaxies, residing in 23 redshift bins up to z = 6, have a sufficiently resolved metallic gas distribution to derive meaningful dust attenuation and emission, with the important caveat that the same dust properties were used at all redshifts. These newly released data complement the already publicly available information about the EAGLE galaxies, which includes intrinsic properties derived by aggregating the properties of the smoothed particles representing matter in the simulation. We further provide an open-source framework of Python procedures for post-processing simulated galaxies with the radiative transfer code SKIRT. The framework allows any third party to calculate synthetic images, spectral energy distributions, and broadband fluxes for EAGLE galaxies, taking into account the effects of dust attenuation and emission.

A Systematic Analysis of Caustic Methods for Galaxy Cluster Masses

NASA Astrophysics Data System (ADS)

Gifford, Daniel; Miller, Christopher; Kern, Nicholas

2013-08-01

We quantify the expected observed statistical and systematic uncertainties of the escape velocity as a measure of the gravitational potential and total mass of galaxy clusters. We focus our attention on low redshift (z <=0.15) clusters, where large and deep spectroscopic datasets currently exist. Utilizing a suite of Millennium Simulation semi-analytic galaxy catalogs, we find that the dynamical mass, as traced by either the virial relation or the escape velocity, is robust to variations in how dynamical friction is applied to "orphan" galaxies in the mock catalogs (i.e., those galaxies whose dark matter halos have fallen below the resolution limit). We find that the caustic technique recovers the known halo masses (M 200) with a third less scatter compared to the virial masses. The bias we measure increases quickly as the number of galaxies used decreases. For N gal > 25, the scatter in the escape velocity mass is dominated by projections along the line-of-sight. Algorithmic uncertainties from the determination of the projected escape velocity profile are negligible. We quantify how target selection based on magnitude, color, and projected radial separation can induce small additional biases into the escape velocity masses. Using N gal = 150 (25), the caustic technique has a per cluster scatter in ln (M|M 200) of 0.3 (0.5) and bias 1% ± 3} (16% ± 5}) for clusters with masses >1014 M ⊙ at z < 0.15.

A radio spectral index map and catalogue at 147-1400 MHz covering 80 per cent of the sky

NASA Astrophysics Data System (ADS)

de Gasperin, F.; Intema, H. T.; Frail, D. A.

2018-03-01

The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS), we produced a large-area radio spectral index map of ˜80 per cent of the sky (Dec. > - 40 deg), as well as a radio spectral index catalogue containing 1396 515 sources, of which 503 647 are not upper or lower limits. Almost every TGSS source has a detected counterpart, while this is true only for 36 per cent of NVSS sources. We released both the map and the catalogue to the astronomical community. The catalogue is analysed to discover systematic behaviours in the cosmic radio population. We find a differential spectral behaviour between faint and bright sources as well as between compact and extended sources. These trends are explained in terms of radio galaxy evolution. We also confirm earlier reports of an excess of steep-spectrum sources along the galactic plane. This corresponds to 86 compact and steep-spectrum source in excess compared to expectations. The properties of this excess are consistent with normal non-recycled pulsars, which may have been missed by pulsation searches due to larger than average scattering along the line of sight.

Modeling the Galaxy-Halo Connection: An open-source approach with Halotools

NASA Astrophysics Data System (ADS)

Hearin, Andrew

2016-03-01

Although the modern form of galaxy-halo modeling has been in place for over ten years, there exists no common code base for carrying out large-scale structure calculations. Considering, for example, the advances in CMB science made possible by Boltzmann-solvers such as CMBFast, CAMB and CLASS, there are clear precedents for how theorists working in a well-defined subfield can mutually benefit from such a code base. Motivated by these and other examples, I present Halotools: an open-source, object-oriented python package for building and testing models of the galaxy-halo connection. Halotools is community-driven, and already includes contributions from over a dozen scientists spread across numerous universities. Designed with high-speed performance in mind, the package generates mock observations of synthetic galaxy populations with sufficient speed to conduct expansive MCMC likelihood analyses over a diverse and highly customizable set of models. The package includes an automated test suite and extensive web-hosted documentation and tutorials (halotools.readthedocs.org). I conclude the talk by describing how Halotools can be used to analyze existing datasets to obtain robust and novel constraints on galaxy evolution models, and by outlining the Halotools program to prepare the field of cosmology for the arrival of Stage IV dark energy experiments.

The AMIGA sample of isolated galaxies. XII. Revision of the isolation degree for AMIGA galaxies using the SDSS

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Leon, S.; Espada, D.; Verdes-Montenegro, L.; Santander-Vela, J. D.; Ruiz, J. E.; Sánchez-Expósito, S.

2013-12-01

Context. To understand the evolution of galaxies, it is necessary to have a reference sample where the effect of the environment is minimized and quantified. In the framework of the AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies), we present a revision of the environment for galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973, Astrof. Issledovaniia Byu. Spec. Ast. Obs., 8, 3) using the ninth data release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: The aims of this study are to refine the photometric-based AMIGA sample of isolated galaxies and to provide an improvement of the quantification of the isolation degree with respect to previous works, using both photometry and spectroscopy. Methods: We developed an automatic method to search for neighbours within a projected area of 1 Mpc radius centred on each primary galaxy to revise the CIG isolation criteria introduced by Karachentseva (1973). The local number density at the fifth nearest neighbour and the tidal strength affecting the CIG galaxy were estimated to quantify the isolation degree. Results: Of the 636 CIG galaxies considered in the photometric study, 426 galaxies fulfil the CIG isolation criteria within 1 Mpc, taking into account projected neighbours. Of the 411 CIG galaxies considered in the spectroscopic study, 347 galaxies fulfil the CIG isolation criteria when a criterion about redshift difference is added. The available redshifts allow us to reject background neighbours and thus improve the photometric assessment. On average, galaxies in the AMIGA sample show lower values in the local number density and the tidal strength parameters than galaxies in denser environments such as pairs, triplets, compact groups, and clusters. Conclusions: For the first time, the environment and the isolation degree of AMIGA galaxies are quantified using digital data. The use of the SDSS database permits one to identify fainter and smaller-size satellites than in previous

Cosmological baryonic and matter densities from 600000 SDSS luminous red galaxies with photometric redshifts

NASA Astrophysics Data System (ADS)

Blake, Chris; Collister, Adrian; Bridle, Sarah; Lahav, Ofer

2007-02-01

We analyse MegaZ-LRG, a photometric-redshift catalogue of luminous red galaxies (LRGs) based on the imaging data of the Sloan Digital Sky Survey (SDSS) 4th Data Release. MegaZ-LRG, presented in a companion paper, contains >106 photometric redshifts derived with ANNZ, an artificial neural network method, constrained by a spectroscopic subsample of ~13000 galaxies obtained by the 2dF-SDSS LRG and Quasar (2SLAQ) survey. The catalogue spans the redshift range 0.4 < z < 0.7 with an rms redshift error σz ~ 0.03(1 + z), covering 5914 deg2 to map out a total cosmic volume 2.5h-3Gpc3. In this study we use the most reliable 600000 photometric redshifts to measure the large-scale structure using two methods: (1) a spherical harmonic analysis in redshift slices, and (2) a direct re-construction of the spatial clustering pattern using Fourier techniques. We present the first cosmological parameter fits to galaxy angular power spectra from a photometric-redshift survey. Combining the redshift slices with appropriate covariances, we determine best-fitting values for the matter density Ωm and baryon density Ωb of Ωmh = 0.195 +/- 0.023 and Ωb/Ωm = 0.16 +/- 0.036 (with the Hubble parameter h = 0.75 and scalar index of primordial fluctuations nscalar = 1 held fixed). These results are in agreement with and independent of the latest studies of the cosmic microwave background radiation, and their precision is comparable to analyses of contemporary spectroscopic-redshift surveys. We perform an extensive series of tests which conclude that our power spectrum measurements are robust against potential systematic photometric errors in the catalogue. We conclude that photometric-redshift surveys are competitive with spectroscopic surveys for measuring cosmological parameters in the simplest `vanilla' models. Future deep imaging surveys have great potential for further improvement, provided that systematic errors can be controlled.

Cold Gas in High-z Galaxies: The CO Gas Excitation Ladder and the need for the ngVLA

NASA Astrophysics Data System (ADS)

Casey, Caitlin M.; Champagne, Jaclyn; Narayanan, Desika; Davé, Romeel; Hung, Chao-Ling; Carilli, Chris; Murphy, Eric Joseph; Decarli, Roberto; Popping, Gergo; Riechers, Dominik A.; Somerville, Rachel; Walter, Fabian

2018-01-01

We will present updated results on a community study led to understand the observable molecular gas properties of high-z galaxies. This work uses a series of high-resolution, hydrodynamic, cosmological zoom-in simulations from MUFASA, the Despotic radiative transfer code that uses simultaneous thermal and statistical equilibrium in calculating molecular and atomic level populations, and a CASA simulator which generates mock ngVLA and ALMA observations. Our work reveals a stark contrast in gas characteristics (geometry and kinematics) as measured from low-J transitions of CO to high-J transitions, demonstrating the need for the ngVLA in probing the cold gas reservoir in the highest-redshift galaxies.

Development of inert density mock materials for HMX

DOE PAGES

Yeager, John D.; Higginbotham Duque, Amanda L.; Shorty, Marvin; ...

2017-09-22

Inert surrogates or mocks for high explosives are commonly used in place of the real material for complex experiments or in situations where safety is a concern. We tested several materials as potential mocks for HMX in terms of density, thermal stability, and processability. Selection criteria were developed and a literature search was conducted primarily using the Cambridge Structural Database. Moreover, out of over 200 potentially acceptable materials, six were chosen for crystallization experiments and a suite of analytical characterization. Of these six, 5-iodo-2'-deoxyuridine, N,N'-bis(2,3,4,5,6-pentafluorophenyl)oxamide, and 2,3,4,5,6-pentafluorobenzamide all were found to be thermally stable at 150°C, matched HMX density asmore » a pressed pellet, and could be crystallized to appropriate particle sizes. These three materials are considered suitable inert density mocks for HMX and will be the subject of future testing.« less

Updated earthquake catalogue for seismic hazard analysis in Pakistan

NASA Astrophysics Data System (ADS)

Khan, Sarfraz; Waseem, Muhammad; Khan, Muhammad Asif; Ahmed, Waqas

2018-03-01

A reliable and homogenized earthquake catalogue is essential for seismic hazard assessment in any area. This article describes the compilation and processing of an updated earthquake catalogue for Pakistan. The earthquake catalogue compiled in this study for the region (quadrangle bounded by the geographical limits 40-83° N and 20-40° E) includes 36,563 earthquake events, which are reported as 4.0-8.3 moment magnitude (M W) and span from 25 AD to 2016. Relationships are developed between the moment magnitude and body, and surface wave magnitude scales to unify the catalogue in terms of magnitude M W. The catalogue includes earthquakes from Pakistan and neighbouring countries to minimize the effects of geopolitical boundaries in seismic hazard assessment studies. Earthquakes reported by local and international agencies as well as individual catalogues are included. The proposed catalogue is further used to obtain magnitude of completeness after removal of dependent events by using four different algorithms. Finally, seismicity parameters of the seismic sources are reported, and recommendations are made for seismic hazard assessment studies in Pakistan.

ReGaTE: Registration of Galaxy Tools in Elixir

PubMed Central

Mareuil, Fabien; Deveaud, Eric; Kalaš, Matúš; Soranzo, Nicola; van den Beek, Marius; Grüning, Björn; Ison, Jon; Ménager, Hervé

2017-01-01

Abstract Background: Bioinformaticians routinely use multiple software tools and data sources in their day-to-day work and have been guided in their choices by a number of cataloguing initiatives. The ELIXIR Tools and Data Services Registry (bio.tools) aims to provide a central information point, independent of any specific scientific scope within bioinformatics or technological implementation. Meanwhile, efforts to integrate bioinformatics software in workbench and workflow environments have accelerated to enable the design, automation, and reproducibility of bioinformatics experiments. One such popular environment is the Galaxy framework, with currently more than 80 publicly available Galaxy servers around the world. In the context of a generic registry for bioinformatics software, such as bio.tools, Galaxy instances constitute a major source of valuable content. Yet there has been, to date, no convenient mechanism to register such services en masse. Findings: We present ReGaTE (Registration of Galaxy Tools in Elixir), a software utility that automates the process of registering the services available in a Galaxy instance. This utility uses the BioBlend application program interface to extract service metadata from a Galaxy server, enhance the metadata with the scientific information required by bio.tools, and push it to the registry. Conclusions: ReGaTE provides a fast and convenient way to publish Galaxy services in bio.tools. By doing so, service providers may increase the visibility of their services while enriching the software discovery function that bio.tools provides for its users. The source code of ReGaTE is freely available on Github at https://github.com/C3BI-pasteur-fr/ReGaTE. PMID:28402416

ReGaTE: Registration of Galaxy Tools in Elixir.

PubMed

Doppelt-Azeroual, Olivia; Mareuil, Fabien; Deveaud, Eric; Kalaš, Matúš; Soranzo, Nicola; van den Beek, Marius; Grüning, Björn; Ison, Jon; Ménager, Hervé

2017-06-01

Bioinformaticians routinely use multiple software tools and data sources in their day-to-day work and have been guided in their choices by a number of cataloguing initiatives. The ELIXIR Tools and Data Services Registry (bio.tools) aims to provide a central information point, independent of any specific scientific scope within bioinformatics or technological implementation. Meanwhile, efforts to integrate bioinformatics software in workbench and workflow environments have accelerated to enable the design, automation, and reproducibility of bioinformatics experiments. One such popular environment is the Galaxy framework, with currently more than 80 publicly available Galaxy servers around the world. In the context of a generic registry for bioinformatics software, such as bio.tools, Galaxy instances constitute a major source of valuable content. Yet there has been, to date, no convenient mechanism to register such services en masse. We present ReGaTE (Registration of Galaxy Tools in Elixir), a software utility that automates the process of registering the services available in a Galaxy instance. This utility uses the BioBlend application program interface to extract service metadata from a Galaxy server, enhance the metadata with the scientific information required by bio.tools, and push it to the registry. ReGaTE provides a fast and convenient way to publish Galaxy services in bio.tools. By doing so, service providers may increase the visibility of their services while enriching the software discovery function that bio.tools provides for its users. The source code of ReGaTE is freely available on Github at https://github.com/C3BI-pasteur-fr/ReGaTE . © The Author 2017. Published by Oxford University Press.

Characterization of flaws in a tube bundle mock-up for reliability studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kupperman, D.S.; Bakhtiari, S.

1997-02-01

As part of an assessment of in-service inspection of steam generator tubes, the authors will assemble a steam generator mock-up for round robin studies and use as a test bed in evaluating emerging technologies. Progress is reported on the characterization of flaws that will be part of the mock-up. Eddy current and ultrasonic techniques are being evaluated as a means to characterize the flaws in the mock-up tubes before final assembly. Twenty Inconel 600 tubes with laboratory-grown cracks, typical of those to be used in the mock-up, were provided by Pacific Northwest National Laboratory for laboratory testing. After the tubesmore » were inspected with eddy current and ultrasonic techniques, they were destructively analyzed to establish the actual depths, lengths, and profiles of the cracks. The analysis of the results will allow the best techniques to be used for characterizing the flaws in the mock-up tubes.« less

The VIMOS Public Extragalactic Redshift Survey (VIPERS). The matter density and baryon fraction from the galaxy power spectrum at redshift 0.6 < z < 1.1

NASA Astrophysics Data System (ADS)

Rota, S.; Granett, B. R.; Bel, J.; Guzzo, L.; Peacock, J. A.; Wilson, M. J.; Pezzotta, A.; de la Torre, S.; Garilli, B.; Bolzonella, M.; Scodeggio, M.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Percival, W. J.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Branchini, E.; Coupon, J.; De Lucia, G.; Ilbert, O.; Moscardini, L.; Moutard, T.

2017-05-01

We use the final catalogue of the VIMOS Public Extragalactic Redshift Survey (VIPERS) to measure the power spectrum of the galaxy distribution at high redshift, presenting results that extend beyond z = 1 for the first time. We apply a fast Fourier transform technique to four independent subvolumes comprising a total of 51 728 galaxies at 0.6 < z < 1.1 (out of the nearly 90 000 included in the whole survey). We concentrate here on the shape of the direction-averaged power spectrum in redshift space, explaining the level of modelling of redshift-space anisotropies and the anisotropic survey window function that are needed to deduce this in a robust fashion. We then use covariance matrices derived from a large ensemble of mock datasets in order to fit the spectral data. The results are well matched by a standard ΛCDM model, with density parameter ΩM h = 0.227+0.063-0.050 and baryon fraction fB=ΩB/ΩM=0.220+0.058-0.072. These inferences from the high-z galaxy distribution are consistent with results from local galaxy surveys, and also with the cosmic microwave background. Thus the ΛCDM model gives a good match to cosmic structure at all redshifts currently accessible to observational study. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly under programme 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

Compiling an earthquake catalogue for the Arabian Plate, Western Asia

NASA Astrophysics Data System (ADS)

Deif, Ahmed; Al-Shijbi, Yousuf; El-Hussain, Issa; Ezzelarab, Mohamed; Mohamed, Adel M. E.

2017-10-01

The Arabian Plate is surrounded by regions of relatively high seismicity. Accounting for this seismicity is of great importance for seismic hazard and risk assessments, seismic zoning, and land use. In this study, a homogenous earthquake catalogue of moment-magnitude (Mw) for the Arabian Plate is provided. The comprehensive and homogenous earthquake catalogue provided in the current study spatially involves the entire Arabian Peninsula and neighboring areas, covering all earthquake sources that can generate substantial hazard for the Arabian Plate mainland. The catalogue extends in time from 19 to 2015 with a total number of 13,156 events, of which 497 are historical events. Four polygons covering the entire Arabian Plate were delineated and different data sources including special studies, local, regional and international catalogues were used to prepare the earthquake catalogue. Moment magnitudes (Mw) that provided by original sources were given the highest magnitude type priority and introduced to the catalogues with their references. Earthquakes with magnitude differ from Mw were converted into this scale applying empirical relationships derived in the current or in previous studies. The four polygons catalogues were included in two comprehensive earthquake catalogues constituting the historical and instrumental periods. Duplicate events were identified and discarded from the current catalogue. The present earthquake catalogue was declustered in order to contain only independent events and investigated for the completeness with time of different magnitude spans.

Hamilton Jeffers and the Double Star Catalogues

NASA Astrophysics Data System (ADS)

Tenn, Joseph S.

2013-01-01

Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Court reporter and amateur astronomer Shelburne Wesley Burnham (1838-1921) published a massive double star catalogue containing more than 13,000 systems in 1906. The next keeper of the double stars was Lick Observatory astronomer Robert Grant Aitken (1864-1951), who produced a much larger catalogue in 1932. Aitken maintained and expanded Burnham’s records of observations on handwritten file cards, eventually turning them over to Lick Observatory astrometrist Hamilton Moore Jeffers (1893-1976). Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby (1921-2002), he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford (1905-2002) had the new 120-inch reflector, the world’s second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the U.S. Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley (1935-1997), and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,000,000 measures of more than 100,000 pairs.

Far-infrared and dust properties of present-day galaxies in the EAGLE simulations

NASA Astrophysics Data System (ADS)

Camps, Peter; Trayford, James W.; Baes, Maarten; Theuns, Tom; Schaller, Matthieu; Schaye, Joop

2016-10-01

The Evolution and Assembly of GaLaxies and their Environments (EAGLE) cosmological simulations reproduce the observed galaxy stellar mass function and many galaxy properties. In this work, we study the dust-related properties of present-day EAGLE galaxies through mock observations in the far-infrared and submm wavelength ranges obtained with the 3D dust radiative transfer code SKIRT. To prepare an EAGLE galaxy for radiative transfer processing, we derive a diffuse dust distribution from the gas particles and we re-sample the star-forming gas particles and the youngest star particles into star-forming regions that are assigned dedicated emission templates. We select a set of redshift-zero EAGLE galaxies that matches the K-band luminosity distribution of the galaxies in the Herschel Reference Survey (HRS), a volume-limited sample of about 300 normal galaxies in the Local Universe. We find overall agreement of the EAGLE dust scaling relations with those observed in the HRS, such as the dust-to-stellar mass ratio versus stellar mass and versus NUV-r colour relations. A discrepancy in the f250/f350 versus f350/f500 submm colour-colour relation implies that part of the simulated dust is insufficiently heated, likely because of limitations in our sub-grid model for star-forming regions. We also investigate the effect of adjusting the metal-to-dust ratio and the covering factor of the photodissociation regions surrounding the star-forming cores. We are able to constrain the important dust-related parameters in our method, informing the calculation of dust attenuation for EAGLE galaxies in the UV and optical domain.

Gas and galaxies in filaments between clusters of galaxies. The study of A399-A401

NASA Astrophysics Data System (ADS)

Bonjean, V.; Aghanim, N.; Salomé, P.; Douspis, M.; Beelen, A.

2018-01-01

We have performed a multi-wavelength analysis of two galaxy cluster systems selected with the thermal Sunyaev-Zel'dovich (tSZ) effect and composed of cluster pairs and an inter-cluster filament. We have focused on one pair of particular interest: A399-A401 at redshift z 0.073 seperated by 3 Mpc. We have also performed the first analysis of one lower-significance newly associated pair: A21-PSZ2 G114.09-34.34 at z 0.094, separated by 4.2 Mpc. We have characterised the intra-cluster gas using the tSZ signal from Planck and, when possible, the galaxy optical and infrared (IR) properties based on two photometric redshift catalogues: 2MPZ and WISExSCOS. From the tSZ data, we measured the gas pressure in the clusters and in the inter-cluster filaments. In the case of A399-A401, the results are in perfect agreement with previous studies and, using the temperature measured from the X-rays, we further estimate the gas density in the filament and find n0 = (4.3 ± 0.7) × 10-4 cm-3. The optical and IR colour-colour and colour-magnitude analyses of the galaxies selected in the cluster system, together with their star formation rate, show no segregation between galaxy populations, both in the clusters and in the filament of A399-A401. Galaxies are all passive, early type, and red and dead. The gas and galaxy properties of this system suggest that the whole system formed at the same time and corresponds to a pre-merger, with a cosmic filament gas heated by the collapse. For the other cluster system, the tSZ analysis was performed and the pressure in the clusters and in the inter-cluster filament was constrained. However, the limited or nonexistent optical and IR data prevent us from concluding on the presence of an actual cosmic filament or from proposing a scenario.

Component fears of claustrophobia associated with mock magnetic resonance imaging.

PubMed

McGlynn, F Dudley; Smitherman, Todd A; Hammel, Jacinda C; Lazarte, Alejandro A

2007-01-01

A conceptualization of claustrophobia [Rachman, S., & Taylor, S. (1993). Analyses of claustrophobia. Journal of Anxiety Disorders, 7, 281-291] was evaluated in the context of magnetic resonance imaging. One hundred eleven students responded to questionnaires that quantified fear of suffocation, fear of restriction, and sensitivity to anxiety symptoms. Sixty-four of them were then exposed to a mock magnetic resonance imaging assessment; maximum subjective fear during the mock assessment was self-reported, behavioral reactions to the mock assessment were characterized, and heart rates before and during the assessment were recorded. Scores for fear of suffocation, fear of restriction, and anxiety sensitivity were used to predict subjective, behavioral, and cardiac fear. Subjective fear during the mock assessment was predicted by fears of suffocation and public anxiousness. Behavioral fear (escape/avoidance) was predicted by fears of restriction and suffocation, and sensitivity to symptoms related to suffocation. Cardiac fear was predicted by fear of public anxiousness. The criterion variance predicted was impressive, clearly sufficient to legitimize both the research preparation and the conceptualization of claustrophobia that was evaluated.

Millimeter wave experiment of ITER equatorial EC launcher mock-up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, K.; Oda, Y.; Kajiwara, K.

2014-02-12

The full-scale mock-up of the equatorial launcher was fabricated in basis of the baseline design to investigate the mm-wave propagation properties of the launcher, the manufacturability, the cooling line management, how to assemble the components and so on. The mock-up consists of one of three mm-wave transmission sets and one of eight waveguide lines can deliver the mm-wave power. The mock-up was connected to the ITER compatible transmission line and the 170GHz gyrotron and the high power experiment was carried out. The measured radiation pattern of the beam at the location of 2.5m away from the EL mock-up shows themore » successful steering capability of 20°∼40°. It was also revealed that the radiated profile at both steering and fixed focusing mirror agreed with the calculation. The result also suggests that some unwanted modes are included in the radiated beam. Transmission of 0.5MW-0.4sec and of 0.12MW-50sec were also demonstrated.« less

Gargantuan Super Spiral Galaxies Loom Large in the Cosmos

NASA Image and Video Library

2016-03-17

In archived NASA data, researchers have discovered "super spiral" galaxies that dwarf our own spiral galaxy, the Milky Way, and compete in size and brightness with the largest galaxies in the universe. The unprecedented galaxies have long hidden in plain sight by mimicking the appearance of typical spirals. Three examples of super spirals are presented here in images taken by the Sloan Digital Sky Survey. The super spiral on the left (Figure 1), catalogued as 2MASX J08542169+0449308, contains two galactic nuclei, instead of just the usual one, and thus looks like two eggs frying in a pan. The central image (Figure 2) shows a super spiral designated 2MASX J16014061+2718161, and it also contains the double nuclei. On the right (Figure 3), a huge galaxy with the moniker SDSS J094700.08+254045.7 stands as one of the biggest and brightest super spirals. The mega-galaxy's starry disk and spiral arms stretch about 320,000 light-years across, or more than three times the breadth of the Milky Way. These double nuclei, which are known to result from the recent merger of two galaxies, could offer a vital hint about the potential origin of super spirals. Researchers speculate that a special merger involving two, gas-rich spiral galaxies could see their pooled gases settle down into a new, larger stellar disk -- presto, a super spiral. The super spirals were discovered using the NASA/IPAC Extragalactic Database, or NED, an online repository containing information on over 100 million galaxies. NED brings together a wealth of data from many different projects, including ultraviolet light observations from the Galaxy Evolution Explorer, visible light from Sloan Digital Sky Survey, infrared light from the 2-Micron All-Sky Survey, and links to data from other missions such as NASA's Spitzer Space Telescope and Wide-Field Infrared Survey Explorer, or WISE. http://photojournal.jpl.nasa.gov/catalog/PIA20064

The XXL Survey. II. The bright cluster sample: catalogue and luminosity function

NASA Astrophysics Data System (ADS)

Pacaud, F.; Clerc, N.; Giles, P. A.; Adami, C.; Sadibekova, T.; Pierre, M.; Maughan, B. J.; Lieu, M.; Le Fèvre, J. P.; Alis, S.; Altieri, B.; Ardila, F.; Baldry, I.; Benoist, C.; Birkinshaw, M.; Chiappetti, L.; Démoclès, J.; Eckert, D.; Evrard, A. E.; Faccioli, L.; Gastaldello, F.; Guennou, L.; Horellou, C.; Iovino, A.; Koulouridis, E.; Le Brun, V.; Lidman, C.; Liske, J.; Maurogordato, S.; Menanteau, F.; Owers, M.; Poggianti, B.; Pomarède, D.; Pompei, E.; Ponman, T. J.; Rapetti, D.; Reiprich, T. H.; Smith, G. P.; Tuffs, R.; Valageas, P.; Valtchanov, I.; Willis, J. P.; Ziparo, F.

2016-06-01

Context. The XXL Survey is the largest survey carried out by the XMM-Newton satellite and covers a total area of 50 square degrees distributed over two fields. It primarily aims at investigating the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. The survey will ultimately uncover several hundreds of galaxy clusters out to a redshift of ~2 at a sensitivity of ~10-14 erg s-1 cm-2 in the [0.5-2] keV band. Aims: This article presents the XXL bright cluster sample, a subsample of 100 galaxy clusters selected from the full XXL catalogue by setting a lower limit of 3 × 10-14 erg s-1 cm-2 on the source flux within a 1' aperture. Methods: The selection function was estimated using a mixture of Monte Carlo simulations and analytical recipes that closely reproduce the source selection process. An extensive spectroscopic follow-up provided redshifts for 97 of the 100 clusters. We derived accurate X-ray parameters for all the sources. Scaling relations were self-consistently derived from the same sample in other publications of the series. On this basis, we study the number density, luminosity function, and spatial distribution of the sample. Results: The bright cluster sample consists of systems with masses between M500 = 7 × 1013 and 3 × 1014 M⊙, mostly located between z = 0.1 and 0.5. The observed sky density of clusters is slightly below the predictions from the WMAP9 model, and significantly below the prediction from the Planck 2015 cosmology. In general, within the current uncertainties of the cluster mass calibration, models with higher values of σ8 and/or ΩM appear more difficult to accommodate. We provide tight constraints on the cluster differential luminosity function and find no hint of evolution out to z ~ 1. We also find strong evidence for the presence of large-scale structures in the XXL bright cluster sample and identify five new superclusters. Based on

Galaxy clusters in the SDSS Stripe 82 based on photometric redshifts

DOE PAGES

Durret, F.; Adami, C.; Bertin, E.; ...

2015-06-10

Based on a recent photometric redshift galaxy catalogue, we have searched for galaxy clusters in the Stripe ~82 region of the Sloan Digital Sky Survey by applying the Adami & MAzure Cluster FInder (AMACFI). Extensive tests were made to fine-tune the AMACFI parameters and make the cluster detection as reliable as possible. The same method was applied to the Millennium simulation to estimate our detection efficiency and the approximate masses of the detected clusters. Considering all the cluster galaxies (i.e. within a 1 Mpc radius of the cluster to which they belong and with a photoz differing by less thanmore » 0.05 from that of the cluster), we stacked clusters in various redshift bins to derive colour-magnitude diagrams and galaxy luminosity functions (GLFs). For each galaxy with absolute magnitude brighter than -19.0 in the r band, we computed the disk and spheroid components by applying SExtractor, and by stacking clusters we determined how the disk-to-spheroid flux ratio varies with cluster redshift and mass. We also detected 3663 clusters in the redshift range 0.1513 and a few 10 14 solar masses. Furthermore, by stacking the cluster galaxies in various redshift bins, we find a clear red sequence in the (g'-r') versus r' colour-magnitude diagrams, and the GLFs are typical of clusters, though with a possible contamination from field galaxies. The morphological analysis of the cluster galaxies shows that the fraction of late-type to early-type galaxies shows an increase with redshift (particularly in high mass clusters) and a decrease with detection level, i.e. cluster mass. From the properties of the cluster galaxies, the majority of the candidate clusters detected here seem to be real clusters with typical cluster properties.« less

Galaxy clusters in the SDSS Stripe 82 based on photometric redshifts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durret, F.; Adami, C.; Bertin, E.

Based on a recent photometric redshift galaxy catalogue, we have searched for galaxy clusters in the Stripe ~82 region of the Sloan Digital Sky Survey by applying the Adami & MAzure Cluster FInder (AMACFI). Extensive tests were made to fine-tune the AMACFI parameters and make the cluster detection as reliable as possible. The same method was applied to the Millennium simulation to estimate our detection efficiency and the approximate masses of the detected clusters. Considering all the cluster galaxies (i.e. within a 1 Mpc radius of the cluster to which they belong and with a photoz differing by less thanmore » 0.05 from that of the cluster), we stacked clusters in various redshift bins to derive colour-magnitude diagrams and galaxy luminosity functions (GLFs). For each galaxy with absolute magnitude brighter than -19.0 in the r band, we computed the disk and spheroid components by applying SExtractor, and by stacking clusters we determined how the disk-to-spheroid flux ratio varies with cluster redshift and mass. We also detected 3663 clusters in the redshift range 0.1513 and a few 10 14 solar masses. Furthermore, by stacking the cluster galaxies in various redshift bins, we find a clear red sequence in the (g'-r') versus r' colour-magnitude diagrams, and the GLFs are typical of clusters, though with a possible contamination from field galaxies. The morphological analysis of the cluster galaxies shows that the fraction of late-type to early-type galaxies shows an increase with redshift (particularly in high mass clusters) and a decrease with detection level, i.e. cluster mass. From the properties of the cluster galaxies, the majority of the candidate clusters detected here seem to be real clusters with typical cluster properties.« less

32 CFR 575.6 - Catalogue, United States Military Academy.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 3 2013-07-01 2013-07-01 false Catalogue, United States Military Academy. 575.6... ADMISSION TO THE UNITED STATES MILITARY ACADEMY § 575.6 Catalogue, United States Military Academy. The latest edition of the catalogue, United States Military Academy, contains additional information...

32 CFR 575.6 - Catalogue, United States Military Academy.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 3 2011-07-01 2009-07-01 true Catalogue, United States Military Academy. 575.6... ADMISSION TO THE UNITED STATES MILITARY ACADEMY § 575.6 Catalogue, United States Military Academy. The latest edition of the catalogue, United States Military Academy, contains additional information...

32 CFR 575.6 - Catalogue, United States Military Academy.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 3 2010-07-01 2010-07-01 true Catalogue, United States Military Academy. 575.6... ADMISSION TO THE UNITED STATES MILITARY ACADEMY § 575.6 Catalogue, United States Military Academy. The latest edition of the catalogue, United States Military Academy, contains additional information...

Stellar populations in the bulges of isolated galaxies

NASA Astrophysics Data System (ADS)

Morelli, L.; Parmiggiani, M.; Corsini, E. M.; Costantin, L.; Dalla Bontà, E.; Méndez-Abreu, J.; Pizzella, A.

2016-12-01

We present photometry and long-slit spectroscopy for 12 S0 and spiral galaxies selected from the Catalogue of Isolated Galaxies. The structural parameters of the sample galaxies are derived from the Sloan Digital Sky Survey I-band images by performing a two-dimensional photometric decomposition of the surface brightness distribution. This is assumed to be the sum of the contribution of a Sérsic bulge, an exponential disc, and a Ferrers bar characterized by elliptical and concentric isophotes with constant ellipticity and position angles. The rotation curves and velocity dispersion profiles of the stellar component are measured from the spectra obtained along the major axis of galaxies. The radial profiles of the Hβ, Mg and Fe line-strength indices are derived too. Correlations between the central values of the Mg2 and line-strength indices and the velocity dispersion are found. The mean age, total metallicity and total α/Fe enhancement of the stellar population in the centre and at the radius, where the bulge gives the same contribution to the total surface brightness as the remaining components, are obtained using stellar population models with variable element abundance ratios. We identify intermediate-age bulges with solar metallicity and old bulges with a large spread in metallicity. Most of the sample bulges display supersolar α/Fe enhancement, no gradient in age and negative gradients of metallicity and α/Fe enhancement. These findings support a formation scenario via dissipative collapse where environmental effects are remarkably less important than in the assembly of bulges of galaxies in groups and clusters.

Deep spectroscopy of nearby galaxy clusters - II. The Hercules cluster

NASA Astrophysics Data System (ADS)

Agulli, I.; Aguerri, J. A. L.; Diaferio, A.; Dominguez Palmero, L.; Sánchez-Janssen, R.

2017-06-01

We carried out the deep spectroscopic observations of the nearby cluster A 2151 with AF2/WYFFOS@WHT. The caustic technique enables us to identify 360 members brighter than Mr = -16 and within 1.3R200. We separated the members into subsamples according to photometrical and dynamical properties such as colour, local environment and infall time. The completeness of the catalogue and our large sample allow us to analyse the velocity dispersion and the luminosity functions (LFs) of the identified populations. We found evidence of a cluster still in its collapsing phase. The LF of the red population of A 2151 shows a deficit of dwarf red galaxies. Moreover, the normalized LFs of the red and blue populations of A 2151 are comparable to the red and blue LFs of the field, even if the blue galaxies start dominating 1 mag fainter and the red LF is well represented by a single Schechter function rather than a double Schechter function. We discuss how the evolution of cluster galaxies depends on their mass: bright and intermediate galaxies are mainly affected by dynamical friction and internal/mass quenching, while the evolution of dwarfs is driven by environmental processes that need time and a hostile cluster environment to remove the gas reservoirs and halt the star formation.

Large-scale correlations in gas traced by Mg II absorbers around low-mass galaxies

NASA Astrophysics Data System (ADS)

Kauffmann, Guinevere

2018-03-01

The physical origin of the large-scale conformity in the colours and specific star formation rates of isolated low-mass central galaxies and their neighbours on scales in excess of 1 Mpc is still under debate. One possible scenario is that gas is heated over large scales by feedback from active galactic nuclei (AGNs), leading to coherent modulation of cooling and star formation between well-separated galaxies. In this Letter, the metal line absorption catalogue of Zhu & Ménard is used to probe gas out to large projected radii around a sample of a million galaxies with stellar masses ˜1010M⊙ and photometric redshifts in the range 0.4 < z < 0.8 selected from Sloan Digital Sky Survey imaging data. This galaxy sample covers an effective volume of 2.2 Gpc3. A statistically significant excess of Mg II absorbers is present around the red-low-mass galaxies compared to their blue counterparts out to projected radii of 10 Mpc. In addition, the equivalent width distribution function of Mg II absorbers around low-mass galaxies is shown to be strongly affected by the presence of a nearby (Rp < 2 Mpc) radio-loud AGNs out to projected radii of 5 Mpc.

The Liverpool-Edinburgh high proper motion catalogue

NASA Astrophysics Data System (ADS)

Pokorny, R. S.; Jones, H. R. A.; Hambly, N. C.; Pinfield, D. J.

2004-07-01

We present a machine selected catalogue of 11 289 objects with proper motions exceeding 0.18 arcsec yr-1 and an R-band faint magnitude limit of 19.5 mag. The catalogue was produced using SuperCOSMOS digitized R-Band ESO and UK Schmidt Plates in 287 Schmidt fields covering almost 7000 square degrees (˜17% of the whole sky) at the South Galactic Cap. The catalogue includes UK Schmidt BJ and I magnitudes for all of the stars as well as 2MASS magnitudes for 10,447 of the catalogue stars. We also show that the NLTT is ˜95% complete for Dec > -32.5°. The full Table \\ref{tab1} is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/421/763

Submillimeter, millimeter, and microwave spectral line catalogue

NASA Technical Reports Server (NTRS)

Poynter, R. L.; Pickett, H. M.

1981-01-01

A computer accessible catalogue of submillimeter, millimeter and microwave spectral lines in the frequency range between 0 and 3000 GHZ (i.e., wavelengths longer than 100 mu m) is presented which can be used a planning guide or as an aid in the identification and analysis of observed spectral lines. The information listed for each spectral line includes the frequency and its estimated error, the intensity, lower state energy, and quantum number assignment. The catalogue was constructed by using theoretical least squares fits of published spectral lines to accepted molecular models. The associated predictions and their estimated errors are based upon the resultant fitted parameters and their covariances. Future versions of this catalogue will add more atoms and molecules and update the present listings (133 species) as new data appear. The catalogue is available as a magnetic tape recorded in card images and as a set of microfiche records.

Probing Inflation Using Galaxy Clustering On Ultra-Large Scales

NASA Astrophysics Data System (ADS)

Dalal, Roohi; de Putter, Roland; Dore, Olivier

2018-01-01

A detailed understanding of curvature perturbations in the universe is necessary to constrain theories of inflation. In particular, measurements of the local non-gaussianity parameter, flocNL, enable us to distinguish between two broad classes of inflationary theories, single-field and multi-field inflation. While most single-field theories predict flocNL ≈ ‑5/12 (ns -1), in multi-field theories, flocNL is not constrained to this value and is allowed to be observably large. Achieving σ(flocNL) = 1 would give us discovery potential for detecting multi-field inflation, while finding flocNL=0 would rule out a good fraction of interesting multi-field models. We study the use of galaxy clustering on ultra-large scales to achieve this level of constraint on flocNL. Upcoming surveys such as Euclid and LSST will give us galaxy catalogs from which we can construct the galaxy power spectrum and hence infer a value of flocNL. We consider two possible methods of determining the galaxy power spectrum from a catalog of galaxy positions: the traditional Feldman Kaiser Peacock (FKP) Power Spectrum Estimator, and an Optimal Quadratic Estimator (OQE). We implemented and tested each method using mock galaxy catalogs, and compared the resulting constraints on flocNL. We find that the FKP estimator can measure flocNL in an unbiased way, but there remains room for improvement in its precision. We also find that the OQE is not computationally fast, but remains a promising option due to its ability to isolate the power spectrum at large scales. We plan to extend this research to study alternative methods, such as pixel-based likelihood functions. We also plan to study the impact of general relativistic effects at these scales on our ability to measure flocNL.

The SCUBA-2 Cosmology Legacy Survey: the clustering of submillimetre galaxies in the UKIDSS UDS field

NASA Astrophysics Data System (ADS)

Wilkinson, Aaron; Almaini, Omar; Chen, Chian-Chou; Smail, Ian; Arumugam, Vinodiran; Blain, Andrew; Chapin, Edward L.; Chapman, Scott C.; Conselice, Christopher J.; Cowley, William I.; Dunlop, James S.; Farrah, Duncan; Geach, James; Hartley, William G.; Ivison, Rob J.; Maltby, David T.; Michałowski, Michał J.; Mortlock, Alice; Scott, Douglas; Simpson, Chris; Simpson, James M.; van der Werf, Paul; Wild, Vivienne

2017-01-01

Submillimetre galaxies (SMGs) are among the most luminous dusty galaxies in the Universe, but their true nature remains unclear; are SMGs the progenitors of the massive elliptical galaxies we see in the local Universe, or are they just a short-lived phase among more typical star-forming galaxies? To explore this problem further, we investigate the clustering of SMGs identified in the SCUBA-2 Cosmology Legacy Survey. We use a catalogue of submillimetre (850 μm) source identifications derived using a combination of radio counterparts and colour/infrared selection to analyse a sample of 610 SMG counterparts in the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Survey (UKIDSS) Ultra Deep Survey (UDS), making this the largest high-redshift sample of these galaxies to date. Using angular cross-correlation techniques, we estimate the halo masses for this large sample of SMGs and compare them with passive and star-forming galaxies selected in the same field. We find that SMGs, on average, occupy high-mass dark matter haloes (Mhalo > 1013 M⊙) at redshifts z > 2.5, consistent with being the progenitors of massive quiescent galaxies in present-day galaxy clusters. We also find evidence of downsizing, in which SMG activity shifts to lower mass haloes at lower redshifts. In terms of their clustering and halo masses, SMGs appear to be consistent with other star-forming galaxies at a given redshift.

SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

NASA Astrophysics Data System (ADS)

Greene, J. E.; Leauthaud, A.; Emsellem, E.; Ge, J.; Aragón-Salamanca, A.; Greco, J.; Lin, Y.-T.; Mao, S.; Masters, K.; Merrifield, M.; More, S.; Okabe, N.; Schneider, D. P.; Thomas, D.; Wake, D. A.; Pan, K.; Bizyaev, D.; Oravetz, D.; Simmons, A.; Yan, R.; van den Bosch, F.

2018-01-01

We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et al. group catalog, we identify central and satellite galaxies in groups with halo masses in the range {10}12.5 {h}-1 {M}ȯ < {M}200b< {10}15 {h}-1 {M}ȯ . As in previous work, we see a sharp dependence on stellar mass, in the sense that ∼70% of galaxies with stellar mass {M}* > {10}11 {h}-2 {M}ȯ tend to have very little rotation, while nearly all galaxies at lower mass show some net rotation. The ∼30% of high-mass galaxies that have significant rotation do not stand out in other galaxy properties, except for a higher incidence of ionized gas emission. Our data are consistent with recent simulation results suggesting that major merging and gas accretion have more impact on the rotational support of lower-mass galaxies. When carefully matching the stellar mass distributions, we find no residual differences in angular momentum content between satellite and central galaxies at the 20% level. Similarly, at fixed mass, galaxies have consistent rotation properties across a wide range of halo mass. However, we find that errors in classification of central and satellite galaxies with group finders systematically lower differences between satellite and central galaxies at a level that is comparable to current measurement uncertainties. To improve constraints, the impact of group-finding methods will have to be forward-modeled via mock catalogs.

Catalogue of Exoplanets in Multiple-Star-Systems

NASA Astrophysics Data System (ADS)

Schwarz, Richard; Funk, Barbara; Bazsó, Ákos; Pilat-Lohinger, Elke

2017-07-01

Cataloguing the data of exoplanetary systems becomes more and more important, due to the fact that they conclude the observations and support the theoretical studies. Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia is available at http://exoplanet.eu/ and described at Schneider et al. 2011). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database. Therefore we started to compile a catalogue for binary and multiple star systems. Since 2013 the catalogue can be found at http://www.univie.ac.at/adg/schwarz/multiple.html (description can be found at Schwarz et al. 2016) which will be updated regularly and is linked to the Extrasolar Planets Encyclopaedia. The data of the binary catalogue can be downloaded as a file (.csv) and used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. Every columns of the list can be sorted in two directions: ascending, meaning from the lowest value to the highest, or descending. In addition an introduction and help is also given in the menu bar of the catalogue including an example list.

Deep Learning Identifies High-z Galaxies in a Central Blue Nugget Phase in a Characteristic Mass Range

NASA Astrophysics Data System (ADS)

Huertas-Company, M.; Primack, J. R.; Dekel, A.; Koo, D. C.; Lapiner, S.; Ceverino, D.; Simons, R. C.; Snyder, G. F.; Bernardi, M.; Chen, Z.; Domínguez-Sánchez, H.; Lee, C. T.; Margalef-Bentabol, B.; Tuccillo, D.

2018-05-01

We use machine learning to identify in color images of high-redshift galaxies an astrophysical phenomenon predicted by cosmological simulations. This phenomenon, called the blue nugget (BN) phase, is the compact star-forming phase in the central regions of many growing galaxies that follows an earlier phase of gas compaction and is followed by a central quenching phase. We train a convolutional neural network (CNN) with mock “observed” images of simulated galaxies at three phases of evolution— pre-BN, BN, and post-BN—and demonstrate that the CNN successfully retrieves the three phases in other simulated galaxies. We show that BNs are identified by the CNN within a time window of ∼0.15 Hubble times. When the trained CNN is applied to observed galaxies from the CANDELS survey at z = 1–3, it successfully identifies galaxies at the three phases. We find that the observed BNs are preferentially found in galaxies at a characteristic stellar mass range, 109.2–10.3 M ⊙ at all redshifts. This is consistent with the characteristic galaxy mass for BNs as detected in the simulations and is meaningful because it is revealed in the observations when the direct information concerning the total galaxy luminosity has been eliminated from the training set. This technique can be applied to the classification of other astrophysical phenomena for improved comparison of theory and observations in the era of large imaging surveys and cosmological simulations.

Are We Really Missing Small Galaxies?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2018-02-01

dark matter, however, the team included baryons in their simulations. They then produced mock observations of the resulting galaxy velocities to see what an observed velocity function would look like for their simulated galaxies.No Problem After All?Comparison of theoretical velocity functions to observations. The black dashed line shows the original, dark-matter-only model predictions; the black solid line includes the effects of detectability. Blue lines show the authors new model, including the effects of detectability and inclusion of baryons. The red and teal data points from observations match this corrected model well. [Brooks et al. 2017]Based on their baryon-inclusive simulations, Brooks and collaborators argue that there are two main factors that have contributed to the seeming theory/observation mismatch of the missing dwarf problem:Galaxies with low velocities arent detectable by our current surveys.The authors found that the detectable fraction of their simulated galaxies plunges as soon as galaxy velocity drops below 35 km/s. They conclude that were probably unable to see a large fraction of the smallest galaxies.Were not correctly inferring the circular velocity of the galaxies.Circular velocity is usually measured by looking at the line width of a gas tracer like HI. The authors find that this doesnt trace the full potential wells of the dwarf galaxies, however, resulting in an incorrect interpretation of their velocities.The authors show that the inclusion of these effects in the theoretical model significantly changes the predicted shape of the galaxy velocity function. This new function beautifully matches observations, neatly eliminating the missing dwarf problem. Perhaps this long-standing mystery has been a problem of interpretation all along!CitationAlyson M. Brooks et al 2017 ApJ 850 97. doi:10.3847/1538-4357/aa9576

The population of early-type galaxies: how it evolves with time and how it differs from passive and late-type galaxies

NASA Astrophysics Data System (ADS)

Tamburri, S.; Saracco, P.; Longhetti, M.; Gargiulo, A.; Lonoce, I.; Ciocca, F.

2014-10-01

Aims: There are two aims to our analysis. On the one hand we are interested in addressing whether a sample of morphologically selected early-type galaxies (ETGs) differs from a sample of passive galaxies in terms of galaxy statistics. On the other hand we study how the relative abundance of galaxies, the number density, and, the stellar mass density for different morphological types change over the redshift range 0.6 ≤ z ≤ 2.5. Methods: From the 1302 galaxies brighter than Ks(AB) = 22 selected from the GOODS-MUSIC catalogue, we classified the ETGs, i.e. elliptical (E) and spheroidal galaxies (E/S0), on the basis of their morphology and the passive galaxies on the basis of their specific star formation rate (sSFR ≤ 10-11 yr-1). Since the definition of a passive galaxy depends on the model parameters assumed to fit the spectral energy distribution of the galaxy, in addition to the assumed sSFR threshold, we probed the dependence of this definition and selection on the stellar initial mass function (IMF). Results: We find that spheroidal galaxies cannot be distinguished from the other morphological classes on the basis of their low star formation rate, irrespective of the IMF adopted in the models. In particular, we find that a large fraction of passive galaxies (>30%) are disc-shaped objects and that the passive selection misses a significant fraction (~26%) of morphologically classified ETGs. Using the sample of 1302 galaxies morphologically classified into spheroidal galaxies (ETGs) and non-spheroidal galaxies (LTGs), we find that the fraction of these two morphological classes is constant over the redshift range 0.6 ≤ z ≤ 2.5, being 20-30% the fraction of ETGs and 70-80% the fraction of LTGs. However, at z < 1 these fractions change among the population of the most massive (M∗ ≥ 1011 M⊙) galaxies, with the fraction of massive ETGs rising up to 40% and the fraction of massive LTGs decreasing to 60%. Parallel to this trend, we find that the number

Galaxy two-point covariance matrix estimation for next generation surveys

NASA Astrophysics Data System (ADS)

Howlett, Cullan; Percival, Will J.

2017-12-01

We perform a detailed analysis of the covariance matrix of the spherically averaged galaxy power spectrum and present a new, practical method for estimating this within an arbitrary survey without the need for running mock galaxy simulations that cover the full survey volume. The method uses theoretical arguments to modify the covariance matrix measured from a set of small-volume cubic galaxy simulations, which are computationally cheap to produce compared to larger simulations and match the measured small-scale galaxy clustering more accurately than is possible using theoretical modelling. We include prescriptions to analytically account for the window function of the survey, which convolves the measured covariance matrix in a non-trivial way. We also present a new method to include the effects of super-sample covariance and modes outside the small simulation volume which requires no additional simulations and still allows us to scale the covariance matrix. As validation, we compare the covariance matrix estimated using our new method to that from a brute-force calculation using 500 simulations originally created for analysis of the Sloan Digital Sky Survey Main Galaxy Sample. We find excellent agreement on all scales of interest for large-scale structure analysis, including those dominated by the effects of the survey window, and on scales where theoretical models of the clustering normally break down, but the new method produces a covariance matrix with significantly better signal-to-noise ratio. Although only formally correct in real space, we also discuss how our method can be extended to incorporate the effects of redshift space distortions.

A SYSTEMATIC ANALYSIS OF CAUSTIC METHODS FOR GALAXY CLUSTER MASSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gifford, Daniel; Miller, Christopher; Kern, Nicholas

We quantify the expected observed statistical and systematic uncertainties of the escape velocity as a measure of the gravitational potential and total mass of galaxy clusters. We focus our attention on low redshift (z {<=}0.15) clusters, where large and deep spectroscopic datasets currently exist. Utilizing a suite of Millennium Simulation semi-analytic galaxy catalogs, we find that the dynamical mass, as traced by either the virial relation or the escape velocity, is robust to variations in how dynamical friction is applied to ''orphan'' galaxies in the mock catalogs (i.e., those galaxies whose dark matter halos have fallen below the resolution limit).more » We find that the caustic technique recovers the known halo masses (M{sub 200}) with a third less scatter compared to the virial masses. The bias we measure increases quickly as the number of galaxies used decreases. For N{sub gal} > 25, the scatter in the escape velocity mass is dominated by projections along the line-of-sight. Algorithmic uncertainties from the determination of the projected escape velocity profile are negligible. We quantify how target selection based on magnitude, color, and projected radial separation can induce small additional biases into the escape velocity masses. Using N{sub gal} = 150 (25), the caustic technique has a per cluster scatter in ln (M|M{sub 200}) of 0.3 (0.5) and bias 1% {+-} 3{r_brace} (16% {+-} 5{r_brace}) for clusters with masses >10{sup 14} M{sub Sun} at z < 0.15.« less

The column density distribution of hard X-ray radio galaxies

NASA Astrophysics Data System (ADS)

Panessa, F.; Bassani, L.; Landi, R.; Bazzano, A.; Dallacasa, D.; La Franca, F.; Malizia, A.; Venturi, T.; Ubertini, P.

2016-09-01

In order to investigate the role of absorption in active galactic nuclei (AGN) with jets, we have studied the column density distribution of a hard X-ray selected sample of radio galaxies, derived from the INTEGRAL/Imager on Board the Integral Satellite (IBIS) and Swift/The Burst Alert Telescope (BAT) AGN catalogues (˜7-10 per cent of the total AGN population). The 64 radio galaxies have a typical FR II radio morphology and are characterized by high 20-100 keV luminosities (from 1042 to 1046 erg s-1) and high Eddington ratios (log LBol/LEdd typically larger than ˜0.01). The observed fraction of absorbed AGN (NH > 1022 cm-2) is around 40 per cent among the total sample, and ˜75 per cent among type 2 AGN. The majority of obscured AGN are narrow-line objects, while unobscured AGN are broad-line objects, obeying to the zeroth-order predictions of unified models. A significant anti-correlation between the radio core dominance parameter and the X-ray column density is found. The observed fraction of Compton thick AGN is ˜2-3 per cent, in comparison with the 5-7 per cent found in radio-quiet hard X-ray selected AGN. We have estimated the absorption and Compton thick fractions in a hard X-ray sample containing both radio galaxies and non-radio galaxies and therefore affected by the same selection biases. No statistical significant difference was found in the absorption properties of radio galaxies and non-radio galaxies sample. In particular, the Compton thick objects are likely missing in both samples and the fraction of obscured radio galaxies appears to decrease with luminosity as observed in hard X-ray non-radio galaxies.

Technology Catalogue. First edition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-02-01

The Department of Energy`s Office of Environmental Restoration and Waste Management (EM) is responsible for remediating its contaminated sites and managing its waste inventory in a safe and efficient manner. EM`s Office of Technology Development (OTD) supports applied research and demonstration efforts to develop and transfer innovative, cost-effective technologies to its site clean-up and waste management programs within EM`s Office of Environmental Restoration and Office of Waste Management. The purpose of the Technology Catalogue is to provide performance data on OTD-developed technologies to scientists and engineers assessing and recommending technical solutions within the Department`s clean-up and waste management programs, asmore » well as to industry, other federal and state agencies, and the academic community. OTD`s applied research and demonstration activities are conducted in programs referred to as Integrated Demonstrations (IDs) and Integrated Programs (IPs). The IDs test and evaluate.systems, consisting of coupled technologies, at specific sites to address generic problems, such as the sensing, treatment, and disposal of buried waste containers. The IPs support applied research activities in specific applications areas, such as in situ remediation, efficient separations processes, and site characterization. The Technology Catalogue is a means for communicating the status. of the development of these innovative technologies. The FY93 Technology Catalogue features technologies successfully demonstrated in the field through IDs and sufficiently mature to be used in the near-term. Technologies from the following IDs are featured in the FY93 Technology Catalogue: Buried Waste ID (Idaho National Engineering Laboratory, Idaho); Mixed Waste Landfill ID (Sandia National Laboratories, New Mexico); Underground Storage Tank ID (Hanford, Washington); Volatile organic compound (VOC) Arid ID (Richland, Washington); and VOC Non-Arid ID (Savannah River Site, South

Young stellar populations in early-type galaxies in the Sloan Digital Sky Survey

NASA Astrophysics Data System (ADS)

Nolan, Louisa A.; Raychaudhury, Somak; Kabán, Ata

2007-02-01

We use a purely data-driven rectified factor analysis to identify early-type galaxies with recent star formation in Data Release 4 of the Sloan Digital Sky Survey Spectroscopic Catalogue. We compare the spectra and environment of these galaxies with those of `normal' early-type galaxies, and a sample of independently selected E+A galaxies. We calculate the projected local galaxy surface density from the nearest five and 10 neighbours (Σ5 and Σ10) for each galaxy in our sample, and find that the dependence on projected local density, of the properties of E+A galaxies, is not significantly different from that of early-type galaxies with young stellar populations, dropping off rapidly towards denser environments, and flattening off at densities <~0.1-0.3 Mpc-2. The dearth of E+A galaxies in dense environments confirms that E+A galaxies are most likely the products of galaxy-galaxy merging or interactions, rather than star-forming galaxies whose star formation has been quenched by processes unique to dense environments, such as ram-pressure stripping or galaxy harassment. We see a tentative peak in the number of E+A galaxies at Σ10 ~ 0.1-0.3 Mpc-2, which may represent the local galaxy density at which the rate of galaxy-galaxy merging or interaction rate peaks. Analysis of the spectra of our early-type galaxies with young stellar populations suggests that they have a stellar component dominated by F stars, ~1-4 Gyr old, together with a mature, metal-rich population characteristic of `typical' early-type galaxies. The young stars represent >~10 per cent of the stellar mass in these galaxies. This, together with the similarity of the environments in which this `E+F' population and the E+A galaxy sample are found, suggests that E+F galaxies used to be E+A galaxies, but have evolved by a further ~ one to a few Gyr. Our rectified factor analysis is sensitive enough to identify this hidden population, which allows us to study the global and intrinsic properties of early

Deriving photometric redshifts using fuzzy archetypes and self-organizing maps - I. Methodology

NASA Astrophysics Data System (ADS)

Speagle, Joshua S.; Eisenstein, Daniel J.

2017-07-01

We propose a method to substantially increase the flexibility and power of template fitting-based photometric redshifts by transforming a large number of galaxy spectral templates into a corresponding collection of 'fuzzy archetypes' using a suitable set of perturbative priors designed to account for empirical variation in dust attenuation and emission-line strengths. To bypass widely separated degeneracies in parameter space (e.g. the redshift-reddening degeneracy), we train self-organizing maps (SOMs) on large 'model catalogues' generated from Monte Carlo sampling of our fuzzy archetypes to cluster the predicted observables in a topologically smooth fashion. Subsequent sampling over the SOM then allows full reconstruction of the relevant probability distribution functions (PDFs). This combined approach enables the multimodal exploration of known variation among galaxy spectral energy distributions with minimal modelling assumptions. We demonstrate the power of this approach to recover full redshift PDFs using discrete Markov chain Monte Carlo sampling methods combined with SOMs constructed from Large Synoptic Survey Telescope ugrizY and Euclid YJH mock photometry.

In-pile testing of ITER first wall mock-ups at relevant thermal loading conditions

NASA Astrophysics Data System (ADS)

Litunovsky, N.; Gervash, A.; Lorenzetto, P.; Mazul, I.; Melder, R.

2009-04-01

The paper describes the experimental technique and preliminary results of thermal fatigue testing of ITER first wall (FW) water-cooled mock-ups inside the core of the RBT-6 experimental fission reactor (RIAR, Dimitrovgrad, Russia). This experiment has provided simultaneous effect of neutron fluence and thermal cycling damages on the mock-ups. A PC-controlled high-temperature graphite ohmic heater was applied to provide cyclic thermal load onto the mock-ups surface. This experiment lasted for 309 effective irradiation days with a final damage level (CuCrZr) of 1 dpa in the mock-ups. About 3700 thermal cycles with a heat flux of 0.4-0.5 MW/m 2 onto the mock-ups were realized before the heater fails. Then, irradiation was continued in a non-cycling mode.

The SCUBA-2 Cosmology Legacy Survey: 850 μm maps, catalogues and number counts

NASA Astrophysics Data System (ADS)

Geach, J. E.; Dunlop, J. S.; Halpern, M.; Smail, Ian; van der Werf, P.; Alexander, D. M.; Almaini, O.; Aretxaga, I.; Arumugam, V.; Asboth, V.; Banerji, M.; Beanlands, J.; Best, P. N.; Blain, A. W.; Birkinshaw, M.; Chapin, E. L.; Chapman, S. C.; Chen, C.-C.; Chrysostomou, A.; Clarke, C.; Clements, D. L.; Conselice, C.; Coppin, K. E. K.; Cowley, W. I.; Danielson, A. L. R.; Eales, S.; Edge, A. C.; Farrah, D.; Gibb, A.; Harrison, C. M.; Hine, N. K.; Hughes, D.; Ivison, R. J.; Jarvis, M.; Jenness, T.; Jones, S. F.; Karim, A.; Koprowski, M.; Knudsen, K. K.; Lacey, C. G.; Mackenzie, T.; Marsden, G.; McAlpine, K.; McMahon, R.; Meijerink, R.; Michałowski, M. J.; Oliver, S. J.; Page, M. J.; Peacock, J. A.; Rigopoulou, D.; Robson, E. I.; Roseboom, I.; Rotermund, K.; Scott, Douglas; Serjeant, S.; Simpson, C.; Simpson, J. M.; Smith, D. J. B.; Spaans, M.; Stanley, F.; Stevens, J. A.; Swinbank, A. M.; Targett, T.; Thomson, A. P.; Valiante, E.; Wake, D. A.; Webb, T. M. A.; Willott, C.; Zavala, J. A.; Zemcov, M.

2017-02-01

We present a catalogue of ˜3000 submillimetre sources detected (≥3.5σ) at 850 μm over ˜5 deg2 surveyed as part of the James Clerk Maxwell Telescope (JCMT) SCUBA-2 Cosmology Legacy Survey (S2CLS). This is the largest survey of its kind at 850 μm, increasing the sample size of 850 μm selected submillimetre galaxies by an order of magnitude. The wide 850 μm survey component of S2CLS covers the extragalactic fields: UKIDSS-UDS, COSMOS, Akari-NEP, Extended Groth Strip, Lockman Hole North, SSA22 and GOODS-North. The average 1σ depth of S2CLS is 1.2 mJy beam-1, approaching the SCUBA-2 850 μm confusion limit, which we determine to be σc ≈ 0.8 mJy beam-1. We measure the 850 μm number counts, reducing the Poisson errors on the differential counts to approximately 4 per cent at S850 ≈ 3 mJy. With several independent fields, we investigate field-to-field variance, finding that the number counts on 0.5°-1° scales are generally within 50 per cent of the S2CLS mean for S850 > 3 mJy, with scatter consistent with the Poisson and estimated cosmic variance uncertainties, although there is a marginal (2σ) density enhancement in GOODS-North. The observed counts are in reasonable agreement with recent phenomenological and semi-analytic models, although determining the shape of the faint-end slope (S850 < 3 mJy) remains a key test. The large solid angle of S2CLS allows us to measure the bright-end counts: at S850 > 10 mJy there are approximately 10 sources per square degree, and we detect the distinctive up-turn in the number counts indicative of the detection of local sources of 850 μm emission, and strongly lensed high-redshift galaxies. All calibrated maps and the catalogue are made publicly available.

Second ROSAT all-sky survey (2RXS) source catalogue

NASA Astrophysics Data System (ADS)

Boller, Th.; Freyberg, M. J.; Trümper, J.; Haberl, F.; Voges, W.; Nandra, K.

2016-04-01

Aims: We present the second ROSAT all-sky survey source catalogue, hereafter referred to as the 2RXS catalogue. This is the second publicly released ROSAT catalogue of point-like sources obtained from the ROSAT all-sky survey (RASS) observations performed with the position-sensitive proportional counter (PSPC) between June 1990 and August 1991, and is an extended and revised version of the bright and faint source catalogues. Methods: We used the latest version of the RASS processing to produce overlapping X-ray images of 6.4° × 6.4° sky regions. To create a source catalogue, a likelihood-based detection algorithm was applied to these, which accounts for the variable point-spread function (PSF) across the PSPC field of view. Improvements in the background determination compared to 1RXS were also implemented. X-ray control images showing the source and background extraction regions were generated, which were visually inspected. Simulations were performed to assess the spurious source content of the 2RXS catalogue. X-ray spectra and light curves were extracted for the 2RXS sources, with spectral and variability parameters derived from these products. Results: We obtained about 135 000 X-ray detections in the 0.1-2.4 keV energy band down to a likelihood threshold of 6.5, as adopted in the 1RXS faint source catalogue. Our simulations show that the expected spurious content of the catalogue is a strong function of detection likelihood, and the full catalogue is expected to contain about 30% spurious detections. A more conservative likelihood threshold of 9, on the other hand, yields about 71 000 detections with a 5% spurious fraction. We recommend thresholds appropriate to the scientific application. X-ray images and overlaid X-ray contour lines provide an additional user product to evaluate the detections visually, and we performed our own visual inspections to flag uncertain detections. Intra-day variability in the X-ray light curves was quantified based on the

A high-significance measurement of correlation between unresolved IRAS sources and optically-selected galaxy clusters

NASA Astrophysics Data System (ADS)

Hincks, Adam D.; Hajian, Amir; Addison, Graeme E.

2013-05-01

We cross-correlate the 100 μm Improved Reprocessing of the IRAS Survey (IRIS) map and galaxy clusters at 0.1 < z < 0.3 in the maxBCG catalogue taken from the Sloan Digital Sky Survey, measuring an angular cross-power spectrum over multipole moments 150 < l < 3000 at a total significance of over 40σ. The cross-spectrum, which arises from the spatial correlation between unresolved dusty galaxies that make up the cosmic infrared background (CIB) in the IRIS map and the galaxy clusters, is well-fit by a single power law with an index of -1.28±0.12, similar to the clustering of unresolved galaxies from cross-correlating far-infrared and submillimetre maps at longer wavelengths. Using a recent, phenomenological model for the spectral and clustering properties of the IRIS galaxies, we constrain the large-scale bias of the maxBCG clusters to be 2.6±1.4, consistent with existing analyses of the real-space cluster correlation function. The success of our method suggests that future CIB-optical cross-correlations using Planck and Herschel data will significantly improve our understanding of the clustering and redshift distribution of the faint CIB sources.

Submillimeter, millimeter, and microwave spectral line catalogue

NASA Technical Reports Server (NTRS)

Poynter, R. L.; Pickett, H. M.

1980-01-01

A computer accessible catalogue of submillimeter, millimeter, and microwave spectral lines in the frequency range between O and 3000 GHz (such as; wavelengths longer than 100 m) is discussed. The catalogue was used as a planning guide and as an aid in the identification and analysis of observed spectral lines. The information listed for each spectral line includes the frequency and its estimated error, the intensity, lower state energy, and quantum number assignment. The catalogue was constructed by using theoretical least squares fits of published spectral lines to accepted molecular models. The associated predictions and their estimated errors are based upon the resultant fitted parameters and their covariances.

Intrinsic alignments in redMaPPer clusters - I. Central galaxy alignments and angular segregation of satellites

NASA Astrophysics Data System (ADS)

Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E.; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Baxter, Eric J.

2016-11-01

The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes and the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Finally, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.

A Detection of the Baryon Acoustic Oscillation Features in the SDSS BOSS DR12 Galaxy Bispectrum

NASA Astrophysics Data System (ADS)

Pearson, David W.; Samushia, Lado

2018-05-01

We present the first high significance detection (4.1σ) of the Baryon Acoustic Oscillations (BAO) feature in the galaxy bispectrum of the twelfth data release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample (0.43 ≤ z ≤ 0.7). We measured the scale dilation parameter, α, using the power spectrum, bispectrum, and both simultaneously for DR12, plus 2048 MultiDark-PATCHY mocks in the North and South Galactic Caps (NGC and SGC, respectively), and the volume weighted averages of those two samples (N+SGC). The fitting to the mocks validated our analysis pipeline, yielding values consistent with the mock cosmology. By fitting to the power spectrum and bispectrum separately, we tested the robustness of our results, finding consistent values from the NGC, SGC and N+SGC in all cases. We found DV = 2032 ± 24(stat.) ± 15(sys.) Mpc, DV = 2038 ± 55(stat.) ± 15(sys.) Mpc, and DV = 2031 ± 22(stat.) ± 10(sys.) Mpc from the N+SGC power spectrum, bispectrum and simultaneous fitting, respectively. Our bispectrum measurement precision was mainly limited by the size of the covariance matrix. Based on the fits to the mocks, we showed that if a less noisy estimator of the covariance were available, from either a theoretical computation or a larger suite of mocks, the constraints from the bispectrum and simultaneous fits would improve to 1.1 per cent (1.3 per cent with systematics) and 0.7 per cent (0.9 per cent with systematics), respectively, with the latter being slightly more precise than the power spectrum only constraints from the reconstructed field.

The Thousand-Ruby Galaxy

NASA Astrophysics Data System (ADS)

2008-09-01

ESO's Wide Field Imager has captured the intricate swirls of the spiral galaxy Messier 83, a smaller look-alike of our own Milky Way. Shining with the light of billions of stars and the ruby red glow of hydrogen gas, it is a beautiful example of a barred spiral galaxy, whose shape has led to it being nicknamed the Southern Pinwheel. Messier 83, M83 ESO PR Photo 25/08 Spiral Galaxy Messier 83 This dramatic image of the galaxy Messier 83 was captured by the Wide Field Imager at ESO's La Silla Observatory, located high in the dry desert mountains of the Chilean Atacama Desert. Messier 83 lies roughly 15 million light-years away towards the huge southern constellation of Hydra (the sea serpent). It stretches over 40 000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies. This very detailed image shows the spiral arms of Messier 83 adorned by countless bright flourishes of ruby red light. These are in fact huge clouds of glowing hydrogen gas. Ultraviolet radiation from newly born, massive stars is ionising the gas in these clouds, causing the great regions of hydrogen to glow red. These star forming regions are contrasted dramatically in this image against the ethereal glow of older yellow stars near the galaxy's central hub. The image also shows the delicate tracery of dark and winding dust streams weaving throughout the arms of the galaxy. Messier 83 was discovered by the French astronomer Nicolas Louis de Lacaille in the mid 18th century. Decades later it was listed in the famous catalogue of deep sky objects compiled by another French astronomer and famous comet hunter, Charles Messier. Recent observations of this enigmatic galaxy in ultraviolet light and radio waves have shown that even its outer desolate regions

A Revised Earthquake Catalogue for South Iceland

NASA Astrophysics Data System (ADS)

Panzera, Francesco; Zechar, J. Douglas; Vogfjörd, Kristín S.; Eberhard, David A. J.

2016-01-01

In 1991, a new seismic monitoring network named SIL was started in Iceland with a digital seismic system and automatic operation. The system is equipped with software that reports the automatic location and magnitude of earthquakes, usually within 1-2 min of their occurrence. Normally, automatic locations are manually checked and re-estimated with corrected phase picks, but locations are subject to random errors and systematic biases. In this article, we consider the quality of the catalogue and produce a revised catalogue for South Iceland, the area with the highest seismic risk in Iceland. We explore the effects of filtering events using some common recommendations based on network geometry and station spacing and, as an alternative, filtering based on a multivariate analysis that identifies outliers in the hypocentre error distribution. We identify and remove quarry blasts, and we re-estimate the magnitude of many events. This revised catalogue which we consider to be filtered, cleaned, and corrected should be valuable for building future seismicity models and for assessing seismic hazard and risk. We present a comparative seismicity analysis using the original and revised catalogues: we report characteristics of South Iceland seismicity in terms of b value and magnitude of completeness. Our work demonstrates the importance of carefully checking an earthquake catalogue before proceeding with seismicity analysis.

The Kinematics Parameters of the Galaxy Using Data of Modern Astrometric Catalogues

NASA Astrophysics Data System (ADS)

Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

Based on the Ogorodnikov-Milne model, we analyze the proper motions of XPM2, UCAC4 and PPMXL stars. To estimate distances to the stars we used the method of statistical parallaxes herewith the random errors of the distance estimations do not exceed 10%. The method of statistical parallaxes was used to estimate the distances to stars with random errors no larger than 14%. The linear solar velocity relative to the local standard of rest, which is well determined for the local entroid (d 150 p), was used as a reference. We have established that the model component that describes the rotation of all stars under consideration about the Galactic Y axis differs from zero. For the distant (d < 1000 pc) PPMXL and UCAC4 stars, the mean rotation about the Galactic Y axis has been found to be M-13 = -0.75± 0.04 mas yr-1. As for distances greater than 1 kpc M-13>derived from the data of only XPM2 catalogue becomes positive and exceeds 0.5 mas yr-1. We interpret this rotation found using the distant stars as a residual rotation of the ICRS/Tycho-2 system relative to the inertial reference frame.

A faculty-led mock residency interview exercise for fourth-year doctor of pharmacy students.

PubMed

Koenigsfeld, Carrie F; Wall, Geoffrey C; Miesner, Andrew R; Schmidt, Ginelle; Haack, Sally L; Eastman, Darla K; Grady, Sarah; Fornoff, Anisa

2012-02-01

To determine whether a faculty-led mock-interview activity enhanced pharmacy student preparation for the residency interview process and increased match rates. Twenty-eight doctor of pharmacy students volunteered for a 40-minute mock-interview session with 2-person faculty teams. A standard roster of 12 interview questions was derived from published literature and the faculty members' experience. Feedback on the student's interview performance was provided verbally during the session. Following the interview, students were given a 2-part survey instrument. The first part of the survey was administered immediately following the mock-interview session and the second part was administered after the standard date for residency program results (known as "Match Day"). Participant match rates were compared to American Society of Health-System Pharmacists (ASHP) national rates. 82.5% (23 of 27) of students in the mock-interview group matched a postgraduate year 1 (PGY1) program. Compared to national rates (61.9%), more students in our surveyed mock-interview group matched a PGY1 residency (P = .015; odds ratio [OR] 3.546, 95% CI 1.161-12.116). Higher match rates were seen in the students completing the mock residency interview compared to ASHP national rates. In general, students completing the mock interview found the process helpful and felt better prepared for their residency interviews.

Galaxy power-spectrum responses and redshift-space super-sample effect

NASA Astrophysics Data System (ADS)

Li, Yin; Schmittfull, Marcel; Seljak, Uroš

2018-02-01

As a major source of cosmological information, galaxy clustering is susceptible to long-wavelength density and tidal fluctuations. These long modes modulate the growth and expansion rate of local structures, shifting them in both amplitude and scale. These effects are often named the growth and dilation effects, respectively. In particular the dilation shifts the baryon acoustic oscillation (BAO) peak and breaks the assumption of the Alcock-Paczynski (AP) test. This cannot be removed with reconstruction techniques because the effect originates from long modes outside the survey. In redshift space, the long modes generate a large-scale radial peculiar velocity that affects the redshift-space distortion (RSD) signal. We compute the redshift-space response functions of the galaxy power spectrum to long density and tidal modes at leading order in perturbation theory, including both the growth and dilation terms. We validate these response functions against measurements from simulated galaxy mock catalogs. As one application, long density and tidal modes beyond the scale of a survey correlate various observables leading to an excess error known as the super-sample covariance, and thus weaken their constraining power. We quantify the super-sample effect on BAO, AP, and RSD measurements, and study its impact on current and future surveys.

Foreground effect on the J-factor estimation of classical dwarf spheroidal galaxies

NASA Astrophysics Data System (ADS)

Ichikawa, Koji; Ishigaki, Miho N.; Matsumoto, Shigeki; Ibe, Masahiro; Sugai, Hajime; Hayashi, Kohei; Horigome, Shun-ichi

2017-07-01

The gamma-ray observation of the dwarf spheroidal galaxies (dSphs) is a promising approach to search for the dark matter annihilation (or decay) signal. The dSphs are the nearby satellite galaxies with a clean environment and dense dark matter halo so that they give stringent constraints on the O(1) TeV dark matter. However, recent studies have revealed that current estimation of astrophysical factors relevant for the dark matter searches are not conservative, where the various non-negligible systematic uncertainties are not taken into account. Among them, the effect of foreground stars on the astrophysical factors has not been paid much attention, which becomes more important for deeper and wider stellar surveys in the future. In this article, we assess the effects of the foreground contamination by generating the mock samples of stars and using a model of future spectrographs. We investigate various data cuts to optimize the quality of the data and find that the cuts on the velocity and surface gravity can efficiently eliminate the contamination. We also propose a new likelihood function that includes the foreground distribution function. We apply this likelihood function to the fit of the three types of the mock data (Ursa Minor, Draco with large dark matter halo and Draco with small halo) and three cases of the observation. The likelihood successfully reproduces the input J-factor value while the fit without considering the foreground distribution gives a large deviation from the input value by a factor of 3.

Dynamical Mass Measurements of Contaminated Galaxy Clusters Using Machine Learning

NASA Astrophysics Data System (ADS)

Ntampaka, M.; Trac, H.; Sutherland, D. J.; Fromenteau, S.; Póczos, B.; Schneider, J.

2016-11-01

We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach. We create two mock catalogs from Multidark’s publicly available N-body MDPL1 simulation, one with perfect galaxy cluster membership information and the other where a simple cylindrical cut around the cluster center allows interlopers to contaminate the clusters. In the standard approach, we use a power-law scaling relation to infer cluster mass from galaxy line-of-sight (LOS) velocity dispersion. Assuming perfect membership knowledge, this unrealistic case produces a wide fractional mass error distribution, with a width of {{Δ }}ε ≈ 0.87. Interlopers introduce additional scatter, significantly widening the error distribution further ({{Δ }}ε ≈ 2.13). We employ the support distribution machine (SDM) class of algorithms to learn from distributions of data to predict single values. Applied to distributions of galaxy observables such as LOS velocity and projected distance from the cluster center, SDM yields better than a factor-of-two improvement ({{Δ }}ε ≈ 0.67) for the contaminated case. Remarkably, SDM applied to contaminated clusters is better able to recover masses than even the scaling relation approach applied to uncontaminated clusters. We show that the SDM method more accurately reproduces the cluster mass function, making it a valuable tool for employing cluster observations to evaluate cosmological models.

Eddington's demon: inferring galaxy mass functions and other distributions from uncertain data

NASA Astrophysics Data System (ADS)

Obreschkow, D.; Murray, S. G.; Robotham, A. S. G.; Westmeier, T.

2018-03-01

We present a general modified maximum likelihood (MML) method for inferring generative distribution functions from uncertain and biased data. The MML estimator is identical to, but easier and many orders of magnitude faster to compute than the solution of the exact Bayesian hierarchical modelling of all measurement errors. As a key application, this method can accurately recover the mass function (MF) of galaxies, while simultaneously dealing with observational uncertainties (Eddington bias), complex selection functions and unknown cosmic large-scale structure. The MML method is free of binning and natively accounts for small number statistics and non-detections. Its fast implementation in the R-package dftools is equally applicable to other objects, such as haloes, groups, and clusters, as well as observables other than mass. The formalism readily extends to multidimensional distribution functions, e.g. a Choloniewski function for the galaxy mass-angular momentum distribution, also handled by dftools. The code provides uncertainties and covariances for the fitted model parameters and approximate Bayesian evidences. We use numerous mock surveys to illustrate and test the MML method, as well as to emphasize the necessity of accounting for observational uncertainties in MFs of modern galaxy surveys.

Halo histories versus galaxy properties at z = 0 II: large-scale galactic conformity

NASA Astrophysics Data System (ADS)

Tinker, Jeremy L.; Hahn, ChangHoon; Mao, Yao-Yuan; Wetzel, Andrew R.; Conroy, Charlie

2018-06-01

Using group catalogues from the Sloan Digital Sky Survey (SDSS) Data Release 7, we measure galactic conformity in the local universe. We measure the quenched fraction of neighbour galaxies around isolated primary galaxies, dividing the isolated sample into star-forming and quiescent objects. We restrict our measurements to scales >1 Mpc to probe the correlations between halo formation histories. Over the stellar mass range 109.7 ≤ M*/M⊙ ≤ 1010.9, we find minimal evidence for conformity. We further compare these data to predictions of the halo age-matching model, in which the oldest galaxies are associated with the oldest haloes. For models with strong correlations between halo and stellar age, the conformity is too large to be consistent with the data. Weaker implementations of the age-matching model would not produce a detectable signal in SDSS data. We reproduce the results of Kauffmann et al., in which the star formation rates of neighbour galaxies are reduced around primary galaxies when the primaries are low star formers. However, we find this result is mainly driven by contamination in the isolation criterion; when removing the small fraction of satellite galaxies in the sample, the conformity signal largely goes away. Lastly, we show that small conformity signals, i.e. 2-5 per cent differences in the quenched fractions of neighbour galaxies, can be produced by mechanisms other than halo assembly bias. For example, if passive galaxies occupy more massive haloes than star-forming galaxies of the same stellar mass, a conformity signal that is consistent with recent measurements from PRIMUS (Berti et al.) can be produced.

Measuring Alignments between Galaxies and the Cosmic Web at z ˜ 2-3 Using IGM Tomography

NASA Astrophysics Data System (ADS)

Krolewski, Alex; Lee, Khee-Gan; Lukić, Zarija; White, Martin

2017-03-01

Many galaxy formation models predict alignments between galaxy spin and the cosmic web (I.e., directions of filaments and sheets), leading to an intrinsic alignment between galaxies that creates a systematic error in weak-lensing measurements. These effects are often predicted to be stronger at high redshifts (z ≳ 1) that are inaccessible to massive galaxy surveys on foreseeable instrumentation, but IGM tomography of the Lyα forest from closely spaced quasars and galaxies is starting to measure the z ˜ 2-3 cosmic web with requisite fidelity. Using mock surveys from hydrodynamical simulations, we examine the utility of this technique, in conjunction with coeval galaxy samples, to measure alignment between galaxies and the cosmic web at z ˜ 2.5. We show that IGM tomography surveys with ≲5 h -1 Mpc sightline spacing can accurately recover the eigenvectors of the tidal tensor, which we use to define the directions of the cosmic web. For galaxy spins and shapes, we use a model parameterized by the alignment strength, {{Δ }}< \\cos θ > , with respect to the tidal tensor eigenvectors from the underlying density field, and also consider observational effects such as errors in the galaxy position angle, inclination, and redshift. Measurements using the upcoming ˜1 deg2 CLAMATO tomographic survey and 600 coeval zCOSMOS-Deep galaxies should place 3σ limits on extreme alignment models with {{Δ }}< \\cos θ > ˜ 0.1, but much larger surveys encompassing >10,000 galaxies, such as Subaru PFS, will be required to constrain models with {{Δ }}< \\cos θ > ˜ 0.03. These measurements will constrain models of galaxy-cosmic web alignment and test tidal torque theory at z ˜ 2, improving our understanding of the physics of intrinsic alignments.

Measuring Alignments between Galaxies and the Cosmic Web at z ~ 2–3 Using IGM Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krolewski, Alex; Lee, Khee-Gan; Luki?, Zarija

Many galaxy formation models predict alignments between galaxy spin and the cosmic web (i.e., directions of filaments and sheets), leading to an intrinsic alignment between galaxies that creates a systematic error in weak-lensing measurements. These effects are often predicted to be stronger at high redshifts (z ≳ 1) that are inaccessible to massive galaxy surveys on foreseeable instrumentation, but IGM tomography of the Lyα forest from closely spaced quasars and galaxies is starting to measure the z ~ 2-3 cosmic web with requisite fidelity. Using mock surveys from hydrodynamical simulations, we examine the utility of this technique, in conjunction withmore » coeval galaxy samples, to measure alignment between galaxies and the cosmic web at z ~ 2.5. We show that IGM tomography surveys with ≲ 5 h -1 Mpc sightline spacing can accurately recover the eigenvectors of the tidal tensor, which we use to define the directions of the cosmic web. For galaxy spins and shapes, we use a model parameterized by the alignment strength, Δ (cos θ), with respect to the tidal tensor eigenvectors from the underlying density field, and also consider observational effects such as errors in the galaxy position angle, inclination, and redshift. Measurements using the upcoming ~ 1 deg 2 CLAMATO tomographic survey and 600 coeval zCOSMOS-Deep galaxies should place 3σ limits on extreme alignment models with Δ (cos θ) ~ 0.1, but much larger surveys encompassing > 10,000 galaxies, such as Subaru PFS, will be required to constrain models with Δ (cos θ) ~ 0.3. These measurements will constrain models of galaxy-cosmic web alignment and test tidal torque theory at z ~ 2, improving our understanding of the physics of intrinsic alignments.« less

Measuring Alignments between Galaxies and the Cosmic Web at z ~ 2–3 Using IGM Tomography

DOE PAGES

Krolewski, Alex; Lee, Khee-Gan; Luki?, Zarija; ...

2017-02-28

Many galaxy formation models predict alignments between galaxy spin and the cosmic web (i.e., directions of filaments and sheets), leading to an intrinsic alignment between galaxies that creates a systematic error in weak-lensing measurements. These effects are often predicted to be stronger at high redshifts (z ≳ 1) that are inaccessible to massive galaxy surveys on foreseeable instrumentation, but IGM tomography of the Lyα forest from closely spaced quasars and galaxies is starting to measure the z ~ 2-3 cosmic web with requisite fidelity. Using mock surveys from hydrodynamical simulations, we examine the utility of this technique, in conjunction withmore » coeval galaxy samples, to measure alignment between galaxies and the cosmic web at z ~ 2.5. We show that IGM tomography surveys with ≲ 5 h -1 Mpc sightline spacing can accurately recover the eigenvectors of the tidal tensor, which we use to define the directions of the cosmic web. For galaxy spins and shapes, we use a model parameterized by the alignment strength, Δ (cos θ), with respect to the tidal tensor eigenvectors from the underlying density field, and also consider observational effects such as errors in the galaxy position angle, inclination, and redshift. Measurements using the upcoming ~ 1 deg 2 CLAMATO tomographic survey and 600 coeval zCOSMOS-Deep galaxies should place 3σ limits on extreme alignment models with Δ (cos θ) ~ 0.1, but much larger surveys encompassing > 10,000 galaxies, such as Subaru PFS, will be required to constrain models with Δ (cos θ) ~ 0.3. These measurements will constrain models of galaxy-cosmic web alignment and test tidal torque theory at z ~ 2, improving our understanding of the physics of intrinsic alignments.« less

Galaxy evolution in groups and clusters: star formation rates, red sequence fractions and the persistent bimodality

NASA Astrophysics Data System (ADS)

Wetzel, Andrew R.; Tinker, Jeremy L.; Conroy, Charlie

2012-07-01

Using galaxy group/cluster catalogues created from the Sloan Digital Sky Survey Data Release 7, we examine in detail the specific star formation rate (SSFR) distribution of satellite galaxies and its dependence on stellar mass, host halo mass and halo-centric radius. All galaxies, regardless of central satellite designation, exhibit a similar bimodal SSFR distribution, with a strong break at SSFR ≈ 10-11 yr-1 and the same high SSFR peak; in no regime is there ever an excess of galaxies in the 'green valley'. Satellite galaxies are simply more likely to lie on the quenched ('red sequence') side of the SSFR distribution. Furthermore, the satellite quenched fraction excess above the field galaxy value is nearly independent of galaxy stellar mass. An enhanced quenched fraction for satellites persists in groups with halo masses down to 3 × 1011 M⊙ and increases strongly with halo mass and towards halo centre. We find no detectable quenching enhancement for galaxies beyond ˜2 Rvir around massive clusters once these galaxies have been decomposed into centrals and satellites. These trends imply that (1) galaxies experience no significant environmental effects until they cross within ˜Rvir of a more massive host halo; (2) after this, star formation in active satellites continues to evolve in the same manner as active central galaxies for several Gyr; and (3) once begun, satellite star formation quenching occurs rapidly. These results place strong constraints on satellite-specific quenching mechanisms, as we will discuss further in companion papers.

Simulated stellar kinematics studies of high-redshift galaxies with the HARMONI Integral Field Spectrograph

NASA Astrophysics Data System (ADS)

Kendrew, S.; Zieleniewski, S.; Houghton, R. C. W.; Thatte, N.; Devriendt, J.; Tecza, M.; Clarke, F.; O'Brien, K.; Häußler, B.

2016-05-01

We present a study into the capabilities of integrated and spatially resolved integral field spectroscopy of galaxies at z = 2-4 with the future HARMONI spectrograph for the European Extremely Large Telescope (E-ELT) using the simulation pipeline, HSIM. We focus particularly on the instrument's capabilities in stellar absorption line integral field spectroscopy, which will allow us to study the stellar kinematics and stellar population characteristics. Such measurements for star-forming and passive galaxies around the peak star formation era will provide a critical insight into the star formation, quenching and mass assembly history of high-z, and thus present-day galaxies. First, we perform a signal-to-noise study for passive galaxies at a range of stellar masses for z = 2-4, assuming different light profiles; for this population, we estimate that integrated stellar absorption line spectroscopy with HARMONI will be limited to galaxies with M* ≳ 1010.7 M⊙. Secondly, we use HSIM to perform a mock observation of a typical star-forming 1010 M⊙ galaxy at z = 3 generated from the high-resolution cosmological simulation NUTFB. We demonstrate that the input stellar kinematics of the simulated galaxy can be accurately recovered from the integrated spectrum in a 15-h observation, using common analysis tools. Whilst spatially resolved spectroscopy is likely to remain out of reach for this particular galaxy, we estimate HARMONI's performance limits in this regime from our findings. This study demonstrates how instrument simulators such as HSIM can be used to quantify instrument performance and study observational biases on kinematics retrieval; and shows the potential of making observational predictions from cosmological simulation output data.

Improved optical mass tracer for galaxy clusters calibrated using weak lensing measurements

NASA Astrophysics Data System (ADS)

Reyes, R.; Mandelbaum, R.; Hirata, C.; Bahcall, N.; Seljak, U.

2008-11-01

We develop an improved mass tracer for clusters of galaxies from optically observed parameters, and calibrate the mass relation using weak gravitational lensing measurements. We employ a sample of ~13000 optically selected clusters from the Sloan Digital Sky Survey (SDSS) maxBCG catalogue, with photometric redshifts in the range 0.1-0.3. The optical tracers we consider are cluster richness, cluster luminosity, luminosity of the brightest cluster galaxy (BCG) and combinations of these parameters. We measure the weak lensing signal around stacked clusters as a function of the various tracers, and use it to determine the tracer with the least amount of scatter. We further use the weak lensing data to calibrate the mass normalization. We find that the best mass estimator for massive clusters is a combination of cluster richness, N200, and the luminosity of the BCG, LBCG: , where is the observed mean BCG luminosity at a given richness. This improved mass tracer will enable the use of galaxy clusters as a more powerful tool for constraining cosmological parameters.

Extending the modeling of the anisotropic galaxy power spectrum to k = 0.4 hMpc-1

NASA Astrophysics Data System (ADS)

Hand, Nick; Seljak, Uroš; Beutler, Florian; Vlah, Zvonimir

2017-10-01

We present a model for the redshift-space power spectrum of galaxies and demonstrate its accuracy in describing the monopole, quadrupole, and hexadecapole of the galaxy density field down to scales of k = 0.4 hMpc-1. The model describes the clustering of galaxies in the context of a halo model and the clustering of the underlying halos in redshift space using a combination of Eulerian perturbation theory and N-body simulations. The modeling of redshift-space distortions is done using the so-called distribution function approach. The final model has 13 free parameters, and each parameter is physically motivated rather than a nuisance parameter, which allows the use of well-motivated priors. We account for the Finger-of-God effect from centrals and both isolated and non-isolated satellites rather than using a single velocity dispersion to describe the combined effect. We test and validate the accuracy of the model on several sets of high-fidelity N-body simulations, as well as realistic mock catalogs designed to simulate the BOSS DR12 CMASS data set. The suite of simulations covers a range of cosmologies and galaxy bias models, providing a rigorous test of the level of theoretical systematics present in the model. The level of bias in the recovered values of f σ8 is found to be small. When including scales to k = 0.4 hMpc-1, we find 15-30% gains in the statistical precision of f σ8 relative to k = 0.2 hMpc-1 and a roughly 10-15% improvement for the perpendicular Alcock-Paczynski parameter α⊥. Using the BOSS DR12 CMASS mocks as a benchmark for comparison, we estimate an uncertainty on f σ8 that is ~10-20% larger than other similar Fourier-space RSD models in the literature that use k <= 0.2 hMpc-1, suggesting that these models likely have a too-limited parametrization.

Commentary: Perception of remorse by mock jurors in a capital murder trial.

PubMed

Batista, Leonardo M; Myers, Wade

2012-01-01