Nicholas Cross - Institute for Astronomy, University of Edinburgh

Nicholas Cross
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Nicholas Cross
Institute for Astronomy, University of Edinburgh
United Kingdom

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Astrophysics (19)
Instrumentation and Methods for Astrophysics (6)
Cosmology and Nongalactic Astrophysics (2)
Physics - Materials Science (1)
Astrophysics of Galaxies (1)

Publications Authored By Nicholas Cross

Atomically thin circuits have recently been explored for applications in next-generation electronics and optoelectronics and have been demonstrated with two-dimensional lateral heterojunctions. In order to form true 2D circuitry from a single material, electronic properties must be spatially tunable. Here, we report tunable transport behavior which was introduced into single layer tungsten diselenide and tungsten disulfide by focused He$^+$ irradiation. Read More

A brief set of notes about the database design for 3D maps of dust extinction in the WFAU Archives, which support data from UKIRT-WFCAM, VISTA and VST. The notes also detail typical use cases, such as getting colour-excesses, extinction-corrections, spectral energy distributions and colour-magnitude diagrams and demonstrate the SQL queries to return data, along with examples from VVV DR2 with bulge extinction maps from Chen et al. (2013). Read More

Authors: Maren Hempel, Dante Minniti, István Dékány, Roberto K. Saito, Philip W. Lucas, Jim Emerson, Andrea V. Ahumada, Suzanne Aigrain, Maria Victoria Alonso, Javier Alonso-García, Eduardo B. Amôres, Rodolfo Angeloni, Julia Arias, Reba Bandyopadhyay, Rodolfo H. Barbá, Beatriz Barbuy, Gustavo Baume, Juan Carlos Beamin, Luigi Bedin, Eduardo Bica, Jordanka Borissova, Leonardo Bronfman, Giovanni Carraro, Márcio Catelan, Juan J. Clariá, Carlos Contreras, Nicholas Cross, Christopher Davis, Richard de Grijs, Janet E. Drew, Cecilia Fariña, Carlos Feinstein, Eduardo Fernández Lajús, Stuart Folkes, Roberto C. Gamen, Douglas Geisler, Wolfgang Gieren, Bertrand Goldman, Oscar González, Andrew Gosling, Guillermo Gunthardt, Sebastian Gurovich, Nigel C. Hambly, Margaret Hanson, Melvin Hoare, Mike J. Irwin, Valentin D. Ivanov, Andrés Jordán, Eamonn Kerins, Karen Kinemuchi, Radostin Kurtev, Andy Longmore, Martin López-Corredoira, Tom Maccarone, Eduardo Martín, Nicola Masetti, Ronald E. Mennickent, David Merlo, Maria Messineo, I. Félix Mirabel, Lorenzo Monaco, Christian Moni Bidin, Lorenzo Morelli, Nelson Padilla, Tali Palma, Maria Celeste Parisi, Quentin Parker, Daniela Pavani, Pawel Pietrukowicz, Grzegorz Pietrzynski, Giuliano Pignata, Marina Rejkuba, Alejandra Rojas, Alexandre Roman-Lopes, Maria Teresa Ruiz, Stuart E. Sale, Ivo Saviane, Matthias R. Schreiber, Anja C. Schröder, Saurabh Sharma, Michael Smith, Laerte Sodré Jr., Mario Soto, Andrew W. Stephens, Motohide Tamura, Claus Tappert, Mark A. Thompson, Ignacio Toledo, Elena Valenti, Leonardo Vanzi, Walter Weidmann, Manuela Zoccali

The VISTA Variables in the V\'ia L\'actea (VVV) survey is one of six public ESO surveys, and is now in its 4th year of observing. Although far from being complete, the VVV survey has already delivered many results, some directly connected to the intended science goals (detection of variables stars, microlensing events, new star clusters), others concerning more exotic objects, e.g. Read More

We describe the VISTA Science Archive (VSA) and its first public release of data from five of the six VISTA Public Surveys. The VSA exists to support the VISTA Surveys through their lifecycle: the VISTA Public Survey consortia can use it during their quality control assessment of survey data products before submission to the ESO Science Archive Facility (ESO SAF); it supports their exploitation of survey data prior to its publication through the ESO SAF; and, subsequently, it provides the wider community with survey science exploitation tools that complement the data product repository functionality of the ESO SAF. This paper has been written in conjunction with the first public release of public survey data through the VSA and is designed to help its users understand the data products available and how the functionality of the VSA supports their varied science goals. Read More

The two fastest near infrared survey telescopes are UKIRT-WFCAM and VISTA. The data from both these instruments are being archived by Wide Field Astronomy Unit (WFAU) at the IfA, Edinburgh, using the same curation pipeline, with some instrument specific processing. The final catalogues from these surveys will contain many tens of billions of detections. Read More

We combine data from the MGC, SDSS and UKIDSS LAS surveys to produce ugrizYJHK luminosity functions and densities from within a common, low redshift volume (z<0.1, ~71,000 h_1^-3 Mpc^3 for L* systems) with 100 per cent spectroscopic completeness. In the optical the fitted Schechter functions are comparable in shape to those previously reported values but with higher normalisations (typically 0, 30, 20, 15, 5 per cent higher phi*-values in u, g, r, i, z respectively over those reported by the SDSS team). Read More

The VISTA Data Flow System comprises nightly pipeline and archiving of near infrared data from UKIRT-WFCAM and VISTA. This includes multi-epoch data which can be used to find moving and variable objects. We have developed a new model for archiving these data which gives the user an extremely flexible and reliable data set that is easy to query through an SQL interface. Read More

Affiliations: 1Astronomy Centre, University of Sussex, 2Astronomy Centre, University of Sussex, 3Institute for Astronomy, University of Edinburgh
Category: Astrophysics

We present luminosity and surface brightness distributions of 40,111 galaxies with K-band photometry from the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS), Data Release 3 and optical photometry from Data Release 5 of the Sloan Digital Sky Survey (SDSS). Various features and limitations of the new UKIDSS data are examined, such as a problem affecting Petrosian magnitudes of extended sources. Selection limits in K- and r-band magnitude, K-band surface brightness and K-band radius are included explicitly in the 1/Vmax estimate of the space density and luminosity function. Read More

Affiliations: 1Scottish Universities Physics Alliance, 2Scottish Universities Physics Alliance, 3Scottish Universities Physics Alliance, 4Scottish Universities Physics Alliance, 5Scottish Universities Physics Alliance, 6Scottish Universities Physics Alliance
Category: Astrophysics

One of the major challenges providing large databases like the WFCAM Science Archive (WSA) is to minimize ingest times for pixel/image metadata and catalogue data. In this article we describe how the pipeline processed data are ingested into the database as the first stage in building a release database which will be succeeded by advanced processing (source merging, seaming, detection quality flagging etc.). Read More

The VDFS comprises the system to pipeline process and archive the data from infrared observations taken by both the WFCAM instrument on UKIRT and the forthcoming VISTA telescope. These include the largest near-IR surveys to date, such as UKIDSS, which produce terabyte sized catalogues of over 10^9 rows. Such large data volumes present a performance challenge when the catalogue data, stored in a relational database, require many iterations of astrometric and photometric recalibration. Read More

Using 10 095 galaxies (B < 20 mag) from the Millennium Galaxy Catalogue, we derive B-band luminosity distributions and selected bivariate brightness distributions for the galaxy population. All subdivisions extract highly correlated sub-sets of the galaxy population which consistently point towards two overlapping distributions. A clear bimodality in the observed distribution is seen in both the rest-(u-r) colour and log(n) distributions. Read More

We measure the luminosity function of morphologically selected E/S0 galaxies from z=0.5 to z=1.0 using deep high resolution Advanced Camera for Surveys (ACS) imaging data. Read More

We recover the joint and individual space density and surface brightness distribution(s) of galaxies from the Millennium Galaxy Catalogue. The MGC is a local survey spanning 30.9 sq deg and probing approximately one--two mag/sq arcsec deeper than either the Two-Degree Field Galaxy Redshift Survey (2dFGRS) or the Sloan Digital Sky Survey (SDSS). Read More

We present new measurements of the galaxy luminosity function (LF) and its dependence on local galaxy density, color, morphology, and clustocentric radius for the massive z=0.83 cluster MS1054-0321. Our analyses are based on imaging performed with the ACS onboard the HST in the F606W, F775W and F850LP passbands and extensive spectroscopic data obtained with the Keck LRIS. Read More

Complementary one-, two-, and three-dimensional tests for detecting the presence of substructure in clusters of galaxies are applied to recently obtained data from the 2dF Galaxy Redshift Survey. The sample of 25 clusters used in this study includes 16 clusters not previously investigated for substructure. Substructure is detected at or greater than the 99% CL level in at least one test for 21 of the 25 clusters studied here. Read More

We derive the fraction of blue galaxies in a sample of clusters at z < 0.11 and the general field at the same redshift. The value of the blue fraction is observed to depend on the luminosity limit adopted, cluster-centric radius and, more generally, local galaxy density, but it does not depend on cluster properties. Read More

Affiliations: 1the 2dFGRS team, 2the 2dFGRS team, 3the 2dFGRS team, 4the 2dFGRS team, 5the 2dFGRS team, 6the 2dFGRS team, 7the 2dFGRS team, 8the 2dFGRS team, 9the 2dFGRS team, 10the 2dFGRS team, 11the 2dFGRS team, 12the 2dFGRS team, 13the 2dFGRS team, 14the 2dFGRS team, 15the 2dFGRS team, 16the 2dFGRS team, 17the 2dFGRS team, 18the 2dFGRS team, 19the 2dFGRS team, 20the 2dFGRS team, 21the 2dFGRS team, 22the 2dFGRS team, 23the 2dFGRS team, 24the 2dFGRS team, 25the 2dFGRS team, 26the 2dFGRS team, 27the 2dFGRS team, 28the 2dFGRS team
Category: Astrophysics

The 2dF Galaxy Redshift Survey (2dFGRS) has obtained spectra for 245591 sources, mainly galaxies, brighter than a nominal extinction-corrected magnitude limit of b_J=19.45. Reliable redshifts were measured for 221414 galaxies. Read More

We present Bivariate Brightness Distributions (BBDs) for four spectral types discriminated by the 2dFGRS. We discuss the photometry and completeness of the 2dFGRS using a deep, wide-field CCD imaging survey. We find that there is a strong luminosity-surface brightness correlation amongst galaxies with medium to strong emission features, with gradient $\beta_{\mu}=0. Read More

In this paper we fit an analytic function to the Bivariate Brightness Distribution (BBD) of galaxies. It is a combination of the classical Schechter Function convolved with a Gaussian distribution in surface brightness: thus incorporating the luminosity-surface brightness correlation as seen in many recent datasets. We fit this function to a recent measurement of the BBD based on 45,000 galaxies from the two-degree field Galaxy Redshift Survey (Cross et al. Read More

We have carried out a study of known clusters within the 2dF Galaxy Redshift Survey (2dFGRS) observed areas and have identified 431 Abell, 173 APM and 343 EDCC clusters. Precise redshifts, velocity dispersions and new centroids have been measured for the majority of these objects, and this information has been used to study the completeness of these catalogues, the level of contamination from foreground and background structures along the cluster's line of sight, the space density of the clusters as a function of redshift, and their velocity dispersion distributions. We find that the Abell and EDCC catalogues are contaminated at the level of about 10%, whereas the APM catalogue suffers only 5% contamination. Read More

Affiliations: 1The 2dFGRS Team, 2The 2dFGRS Team, 3The 2dFGRS Team, 4The 2dFGRS Team, 5The 2dFGRS Team, 6The 2dFGRS Team, 7The 2dFGRS Team, 8The 2dFGRS Team, 9The 2dFGRS Team, 10The 2dFGRS Team, 11The 2dFGRS Team, 12The 2dFGRS Team, 13The 2dFGRS Team, 14The 2dFGRS Team, 15The 2dFGRS Team, 16The 2dFGRS Team, 17The 2dFGRS Team, 18The 2dFGRS Team, 19The 2dFGRS Team, 20The 2dFGRS Team, 21The 2dFGRS Team, 22The 2dFGRS Team, 23The 2dFGRS Team, 24The 2dFGRS Team, 25The 2dFGRS Team, 26The 2dFGRS Team, 27The 2dFGRS Team
Category: Astrophysics

We combine the 2MASS extended source catalogue and the 2dFGRS to produce an IR selected galaxy catalogue with 17,173 measured redshifts. We use this extensive dataset to estimate the J and K-band galaxy luminosity functions. The LFs are fairly well fit by Schechter functions with J: M*-5log h= -22. Read More

We present the bivariate brightness distribution (BBD) for the 2dF Galaxy Redshift Survey (2dFGRS) based on a preliminary subsample of 45,000 galaxies. The BBD is an extension of the galaxy luminosity function incorporating surface brightness information. It allows the measurement of the local luminosity density, j_B, and the galaxy luminosity and surface brightness distributions while accounting for surface brightness selection biases. Read More

Affiliations: 1University of St Andrews, 2University of St Andrews, 3University of St Andrews
Category: Astrophysics

We discuss the quantification of the local galaxy population and the impact of the ``New Era of Wide-Field Astronomy'' on this field, and, in particular, systematic errors in the measurement of the Luminosity Function. New results from the 2dFGRS are shown in which some of these selection effects have been removed. We introduce an INT-WFS project which will further reduce the selection biases. Read More

Affiliations: 1University of St Andrews, 2University of St Andrews
Category: Astrophysics

We discuss the optical parameter space (luminosity and surface brightness) over which galaxies are known to exist and report on the results from three recent datasets: the Two-degree Field Galaxy Redshift Survey, the Hubble Deep Field north, and the Local Group. These data are combined to provide a unique and comprehensive insight into the luminosity distribution of galaxies over the range -24 < M(B) < -8 mags, and the surface brightness distribution over the range 18 < SB(Effective) < 28 mags/sq arcsec. The main conclusions are: (1) luminous low surface brightness galaxies are rare; (2) there exists a universal luminosity-surface brightness relation; (3) the most numerous galaxies are low luminosity low surface brightness dwarfs. Read More