O. Lahav

Publication List Details

Period

1993 - 2009

Number

114

Co-Authors

A sonic black hole in a density-inverted Bose-Einstein condensate (2009)

Lahav, O., Itah, A., Blumkin, A., Gordon, C., Steinhauer, J.

We have created the analogue of a black hole in a Bose-Einstein condensate. In this sonic black hole, sound waves, rather than light waves, cannot escape the event horizon. The black hole is realized...

Direct observation of number squeezing in an optical lattice (2009)

Itah, A., Veksler, H., Lahav, O., Blumkin, A., Moreno, C., Gordon, C., ...

We present an in-situ study of an optical lattice with tunneling and single lattice site resolution. This system provides an important step for realizing a quantum computer. The real-space images...

acquisition of spatial cognitive mapping, orientation (2009)

O Lahav, D Mioduser

virtual environment for supporting blind persons’

Galaxy And Mass Assembly (GAMA) (2008)

Driver, S. P., Baldry, I. K., Bamford, S., Bland-Hawthorn, J., Bridges, T., Cameron, E., ...

The GAMA survey aims to deliver 250,000 optical spectra (3–7°A resolution) over 250 sq. degrees to spectroscopic limits of rAB < 19.8 and KAB < 17.0 mag. Complementary imaging will be provided by...

of Galaxy Spectra (2007)

S. R. Folkes, O. Lahav, S. J. Maddox

We present a method for automated classification of galaxies with low signal-to-noise (S/N) spectra typical of redshift surveys. We develop spectral simulations based on the parameters for the 2dF...

2 (2007)

S. L. Bridle, M. P. Hobson, A. N. Lasenby, O. Lahav, G. Rocha

Observations of large scale structure (LSS) and the Cosmic Microwave Background (CMB) each place separate constraints on the values of cosmological parameters. We calculate a joint likelihood based...

Predicting spectral features in galaxy spectra from broad-band photometry (2007)

Abdalla, F. B., Mateus, A., Santos, W. A., Sodre Jr, L., Ferreras, I., Lahav, O.

We explore the prospects of predicting emission line features present in galaxy spectra given broad-band photometry alone. There is a general consent that colours, and spectral features, most notably...

Photo-z for weak lensing tomography from space: the role of optical and near-IR photometry (2007)

Abdalla, F. B., Amara, A., Capak, P., Cypriano, E. S., Lahav, O., Rhodes, J.

We study in detail the photometric redshift requirements needed for tomographic weak gravitational lensing in order to measure accurately the Dark Energy equation of state. In particular, we examine...

MegaZ-LRG: a photometric redshift catalogue of one million SDSS luminous red galaxies (2007)

Collister, A, Lahav, O, Blake, C, Cannon, R, Croom, S, Drinkwater, M, ...

We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The...

MegaZ-LRG:a photometric redshift catalogue of one million SDSS luminous red galaxies (2007)

Collister, A., Lahav, O., Blake, C., Cannon, Russell, Croom, Scott, Drinkwater, M. J., ...

We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The...

MegaZ-LRG:a photometric redshift catalogue of one million SDSS luminous red galaxies (2007)

Collister, A., Lahav, O., Blake, C., Cannon, Russell, Croom, Scott, Drinkwater, M. J., ...

We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The...

Principal Component Analysis as a tool to explore star formation histories (2006)

Ferreras, I., Rogers, B., Lahav, O.

Principal Component Analysis (PCA) is a well-known multivariate technique used to decorrelate a set of vectors. PCA has been extensively applied in the past to the classification of stellar and...

The dipole anisotropy of the 2 Micron All-Sky Redshift Survey (2006)

Erdoğdu, Pirin, Huchra, J. P., Lahav, O., Colless, M., Cutri, R. M., Falco, E., ...

We estimate the acceleration on the Local Group (LG) from the 2 Micron All-Sky Redshift Survey (2MRS). The sample used includes about 23 200 galaxies with extinction-corrected magnitudes brighter...

The Dipole Anisotropy of the 2mass Redshift Survey (2006)

Erdogdu, P., Huchra, J. P., Lahav, O., Colless, M., Cutri, R. M., Falco, E., ...

We estimate the flux weighted acceleration on the Local Group (LG) from the near-infrared Two Micron All Sky Redshift Survey (2MRS). The near-infrared flux weighted dipoles are very robust because...

The dipole anisotropy of the 2 Micron All-Sky Redshift Survey (2006)

Erdoğdu, P, Huchra, J. P, Macri, L, Mader, J, Martimbeau, N, Pahre, M, ...

We estimate the acceleration on the Local Group (LG) from the 2 Micron All-Sky Redshift Survey (2MRS). The sample used includes about 23 200 galaxies with extinction-corrected magnitudes brighter...

The dipole anisotropy of the 2 Micron All-Sky Redshift Survey (2006)

Erdoğdu, P, Huchra, J. P, Macri, L, Mader, J, Martimbeau, N, Pahre, M, ...

We estimate the acceleration on the Local Group (LG) from the 2 Micron All-Sky Redshift Survey (2MRS). The sample used includes about 23 200 galaxies with extinction-corrected magnitudes brighter...

A Principal Component Analysis approach to the Star Formation History of elliptical galaxies in Compact Groups (2005)

Ferreras, I., Pasquali, A., De Carvalho, R. R., De La Rosa, I. G., Lahav, O.

(Abridged) Environmental differences in the stellar populations of early-type galaxies are explored using principal component analysis (PCA), focusing on differences between elliptical galaxies in...

The 2dF Galaxy Redshift survey : power-spectrum analysis of the final data set and cosmological implications. (2005)

Cole, S., Percival, W. J., Peacock, J. A., Norberg, P., Baugh, C. M., Frenk, C. S., ...

We present a power-spectrum analysis of the final 2dF Galaxy Redshift Survey (2dFGRS), employing a direct Fourier method. The sample used comprises 221 414 galaxies with measured redshifts. We...

The Dipole Anisotropy of the 2 Micron All-Sky Redshift Survey (2005)

Erdogdu, P., Huchra, J. P., Lahav, O., Colless, M., Cutri, R. M., Falco, E., ...

We estimate the acceleration on the Local Group (LG) from the Two Micron All Sky Redshift Survey (2MRS). The sample used includes about 23,200 galaxies with extinction corrected magnitudes brighter...

The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications (2005)

Cole, S., Percival, W. J., Peacock, J. A., Norberg, P., Baugh, C. M., Frenk, C. S., ...

We present a power spectrum analysis of the final 2dF Galaxy Redshift Survey, employing a direct Fourier method. The sample used comprises 221,414 galaxies with measured redshifts. We investigate in...

Galaxy groups in the two-degree field galaxy Redshift survey : the luminous content of the groups. (2004)

Eke, V. R., Frenk, C. S., Baugh, C. M., Cole, S., Norberg, P., Peacock, J. A., ...

The Two-degree Field Galaxy Redshift Survey (2dFGRS) Percolation-Inferred Galaxy Group (2PIGG) catalogue of 29 000 objects is used to study the luminous content of galaxy systems of various sizes....

The 2dF Galaxy Redshift Survey: luminosity functions by density environment and galaxy type (2004)

Croton, Darren J., Farrar, Glennys R., Norberg, Peder, Colless, Matthew, Peacock, John A., Baldry, I. K., ...

We use the 2dF Galaxy Redshift Survey to measure the dependence of the bJ-band galaxy luminosity function on large-scale environment, defined by density contrast in spheres of radius 8h-1Mpc, and on...

Fundamental study of a one-step ambient temperature ferrite process for treatment of acid mine drainage waters: rapid communication (2004)

Morgan, BE, Loewenthal, RE, Lahav, O

A novel approach towards the removal of iron and heavy metals from South African acid mine drainage (AMD) waters is presented. The approach involves the controlled oxidation of ferrous-containing AMD...

The nature of the relative bias between galaxies of different spectral type in 2dFGRS (2004)

Conway, E., Maddox, S., Wild, V., Peacock, J. A., Hawkins, E., Norberg, P., ...

We present an analysis of the relative bias between early- and late-type galaxies in the Two-degree Field Galaxy Redshift Survey (2dFGRS). Our analysis examines the joint counts in cells between...

ANNz: estimating photometric redshifts using artificial neutral networks (2004)

Collister, A.A., Lahav, O.

We introduce ANNz, a freely available software package for photometric redshift estimation using Artificial Neural Networks. ANNz learns the relation between photometry and redshift from an...

Galaxy ecology : groups and low-density environments in the SDSS and 2dFGRS. (2004)

Baugh, C., Bower, R., Cole, S., Eke, V., Baldry, I. K., Balogh, M., ...

We analyse the observed correlation between galaxy environment and Hα emission-line strength, using volume-limited samples and group catalogues of 24 968 galaxies at 0.05

Galaxy groups in the 2dFGRS : the group-finding algorithm and the 2PIGG catalogue. (2004)

Eke, V. R., Baugh, C. M., Cole, S., Frenk, C. S., Norberg, P., Peacock, J. A., ...

The construction of a catalogue of galaxy groups from the Two-degree Field Galaxy Redshift Survey (2dFGRS) is described. Groups are identified by means of a friends-of-friends percolation algorithm...

The 2dF Galaxy Redshift Survey: The clustering of galaxy groups (2004)

Padilla, Nelson D., Baugh, C. M., Eke, V. R., Norberg, P., Cole, S., Frenk, C. S., ...

We measure the clustering of galaxy groups in the 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue. The 2PIGG sample has 29,000 groups with at least two members. The clustering amplitude of...

Galaxy groups in the 2dFGRS: the luminous content of the groups (2004)

Eke, V. R., Frenk, C. S., Baugh, C. M., Cole, S., Norberg, P., Peacock, J. A., ...

The 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue of ~29000 objects is used to study the luminous content of galaxy systems of various sizes. Mock galaxy catalogues constructed from...

Galaxy groups in the 2dFGRS: the group-finding algorithm and the 2PIGG catalogue (2004)

Eke, V. R., Baugh, C. M., Cole, S., Frenk, C. S., Norberg, P., Peacock, J. A., ...

The construction of a catalogue of galaxy groups from the 2-degree Field Galaxy Redshift Survey (2dFGRS) is described. Groups are identified by means of a friends-of-friends percolation algorithm...

The 2dF Galaxy Redshift Survey: higher order galaxy correlation functions (2004)

Croton, D. J., Gaztanaga, E., Baugh, C. M., Norberg, P., Colless, M., Baldry, I. K., ...

We measure moments of the galaxy count probability distribution function in the two-degree field galaxy redshift survey (2dFGRS). The survey is divided into volume limited subsamples in order to...

The 2dF Galaxy Redshift Survey: Hierarchical galaxy clustering (2004)

Baugh, C. M., Croton, D. J., Gaztanaga, E., Norberg, P., Colless, M., Baldry, I. K., ...

We use the two-degree field Galaxy Redshift Survey (2dFGRS) to test the hierarchical scaling hypothesis: namely, that the $p$-point galaxy correlation functions can be written in terms of the two...

The 2dF Galaxy Redshift Survey: voids and hierarchical scaling models (2004)

Croton, D. J., Colless, M., Gaztanaga, E., Baugh, C. M., Norberg, P., Baldry, I. K., ...

We measure the redshift space reduced void probability function (VPF) for 2dFGRS volume limited galaxy samples covering the absolute magnitude range M_bJ-5logh=-18 to -22. Theoretically, the VPF...

Blind persons’ acquisition of spatial cognitive mapping and orientation skills supported by virtual environment (2004)

O Lahav, D Mioduser

Mental mapping of spaces, and of the possible paths for navigating these spaces, is essential for the development of efficient orientation and mobility skills. Most of the information required for...

The 2dF Galaxy Redshift Survey: galaxy clustering per spectral type (2003)

Madgwick, D. S., Hawkins, E., Lahav, O., Maddox, S., Norberg, P., Peacock, J., ...

We have calculated the two-point correlation functions in redshift space, xi(sigma,pi), for galaxies of different spectral types in the 2dF Galaxy Redshift Survey. Using these correlation functions...

The 2dF Galaxy Redshift Survey: the luminosity function of cluster galaxies (2002)

De Propris, Roberto, Colless, M., Driver, S., Couch, W., Peacock, J., Baldry, I., ...

We have determined the composite luminosity function (LF) for galaxies in 60 clusters from the 2dF Galaxy Redshift Survey. The LF spans the range $-22.5

The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe (2002)

Hawkins, E., Maddox, S., Cole, S., Lahav, O., Madgwick, D., Norberg, P., ...

We present a detailed analysis of the two-point correlation function, from the 2dF Galaxy Redshift Survey (2dFGRS). We estimate the redshift-space correlation function, xi(s), from which we measure...

The 2dF Galaxy Redshift survey : the bJ-band galaxy luminosity function and survey selection function. (2002)

Norberg, P., Cole, S., Baugh, C. M., Frenk, C. S., Baldry, I., Bland-Hawthorn, J., ...

We use more than 110 500 galaxies from the 2dF Galaxy Redshift Survey (2dFGRS) to estimate the bJ-band galaxy luminosity function at redshift z= 0, taking account of evolution, the distribution of...

A new upper limit on the total neutrino mass from the 2dF galaxy redshift survey (2002)

Elgaroy, O., Lahav, O., Percival, W.J., Peacock, J.A., Madgwick, D.S., Bridle, S.L., ...

We constrain fν≡Ων/Ωm, the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2 Degree Field Galaxy...

The 2dF galaxy redshift survey: the amplitudes of fluctuations in the 2dFGRS and the CMB, and implications for galaxy biasing (2002)

Lahav, O., Bridle, S.L., Percival, W.J., Peacock, J.A., Efstathiou, G., Baugh, C.M., ...

We compare the amplitudes of fluctuations probed by the 2dF Galaxy Redshift Survey (2dFGRS) and by the latest measurements of the cosmic microwave background (CMB) anisotropies. By combining the...

The 2dF Galaxy Redshift Survey : the dependence of galaxy clustering on luminosity and spectral type. (2002)

Norberg, P., Baugh, C. M., Hawkins, E., Maddox, S., Madgwick, D., Lahav, O., ...

We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal-component analysis of...

The 2dF Galaxy Redshift survey : the dependence of galaxy clustering on luminosity and spectral type. (2002)

Norberg, P., Baugh, C. M., Hawkins, E., Maddox, S., Madgwick, D., Lahav, O., ...

We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal-component analysis of...

The 2dF galaxy redshift survey: galaxy luminosity functions per spectral type (2002)

Madgwick, D.S., Lahav, O., Baldry, I.K., Baugh, C.M., Bland-Hawthorn, J., Bridges, T., ...

We calculate the optical bJ luminosity function (LF) of the 2dF Galaxy Redshift Survey (2dFGRS) for different subsets defined by their spectral properties. These spectrally selected subsets are...

Studying large-scale structure with the 2dF Galaxy Redshift Survey (2002)

Peacock, J. A., Colless, M., Baldry, I., Baugh, C., Bland-Hawthorn, J., Bridges, T. J., ...

The 2dF Galaxy Redshift Survey is the first to observe more than 100,000 redshifts. This allows precise measurements of many of the key statistics of galaxy clustering, in particular redshift-space...

A new upper limit on the total neutrino mass from the 2dF Galaxy Redshift Survey (2002)

Elgaroy, O., Lahav, O., Percival, W. J., Peacock, J. A., Madgwick, D. S., Bridle, S. L., ...

We constrain f_nu = Omega_nu / Omega_m, the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2dF Galaxy...

Combining cosmological datasets: hyperparameters and Bayesian evidence (2002)

Hobson, M. P., Bridle, S. L., Lahav, O.

A method is presented for performing joint analyses of cosmological datasets, in which the weight assigned to each dataset is determined directly by it own statistical properties. The weights are...

New upper limit on the total neutrino mass from the 2 degree field galaxy redshift survey (2002)

Elgary, O., Lahav, O., Percival, W. J., Peacock, J. A., Madgwick, D. S., Bridle, S. L., ...

The shape of the 2 Degree Field Galaxy Redshift Survey (2dFGRS) power spectrum was analyzed to obtain an upper bound on the fractional contribution of massive neutrinos to the total mass density, fv....

New upper limit on the total neutrino mass from the 2 degree field galaxy redshift survey (2002)

Elgary, O., Lahav, O., Percival, W. J., Peacock, J. A., Madgwick, D. S., Bridle, S. L., ...

The shape of the 2 Degree Field Galaxy Redshift Survey (2dFGRS) power spectrum was analyzed to obtain an upper bound on the fractional contribution of massive neutrinos to the total mass density, fv....

The 2dF Galaxy Redshift Survey: The bias of galaxies and the density of the Universe (2001)

Verde, Licia, Heavens, Alan F., Percival, Will J., Matarrese, Sabino, Baugh, C. M., Bland-Hawthorn, J., ...

We compute the bispectrum of the 2dF Galaxy Redshift Survey (2dFGRS) and use it to measure the bias parameter of the galaxies. This parameter quantifies the strength of clustering of the galaxies...

The 2dF Galaxy Redshift Survey: The dependence of galaxy clustering on luminosity and spectral type (2001)

Norberg, P., Baugh, C. M., Hawkins, E., Maddox, S., Madgwick, D., Lahav, O., ...

We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal component analysis of...

The 2dF galaxy redshift survey : near-infrared galaxy luminosity functions. (2001)

Cole, S., Norberg, P., Baugh, C. M., Frenk, C. S., Bland-Hawthorn, J., Bridges, T., ...

We combine the Two Micron All Sky Survey (2MASS) Extended Source Catalogue and the 2dF Galaxy Redshift Survey to produce an infrared selected galaxy catalogue with 17 173 measured redshifts. We use...

Features in the primordial power spectrum: constraints from the CMB and the limitation of the 2dF and SDSS redshift surveys to detect them (2001)

Elgaroy, O., Gramann, M., Lahav, O.

We allow a more general (step-function) form of the primordial power spectrum than the usual featureless power-law Harrison--Zeldovich (with spectral index n=1) power spectrum, and fit it to the...

The 2dF Galaxy Redshift Survey: The b_J-band galaxy luminosity function and survey selection function (2001)

Norberg, P., Cole, S., Baugh, C., Frenk, C., Baldry, I., Bland-Hawthorn, J., ...

We use more than 110500 galaxies from the 2dF galaxy redshift survey (2dFGRS) to estimate the b_J-band galaxy luminosity function at redshift z=0, taking account of evolution, the distribution of...

The 2dF Galaxy Redshift survey : luminosity dependence of galaxy clustering. (2001)

Norberg, P., Baugh, C. M., Hawkins, E., Maddox, S., Peacock, J. A., Cole, S., ...

We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of...

The 2dF Galaxy Redshift Survey: constraints on cosmic star-formation history from the cosmic spectrum (2001)

Baldry, I. K., Glazebrook, K., Baugh, C. M., Bland-Hawthorn, J., Bridges, T., Cannon, R., ...

We present the first results on the history of star formation in the Universe based on the `cosmic spectrum', in particular, the volume-averaged, luminosity-weighted, stellar absorption line spectrum...

The z ~ 1.2 Galaxy Luminosity Function from The LCIR Survey (2001)

McCarthy, P. J., Marzke, R. O., Carlberg, R. G., Firth, A. E., Persson, S. E., ...

We present results from the Las Campanas Infrared Survey, designed to identify a statistically significant sample of z>=1 galaxies using photometric redshift techniques. Here we summarize the design...

The Las Campanas IR Survey. II. Photometric redshifts, comparison with models and clustering evolution (2001)

Firth, A. E., Somerville, R. S., McMahon, R. G., Lahav, O., Ellis, R. S., Sabbey, C. N., ...

The LCIR Survey, using the Cambridge IR Survey Instrument (CIRSI), reaches H \~ 20-21 over ~1 deg^2. We present results for 744 arcmin^2 in which public UBVRI data exist. We compare optical-IR...

The Las Campanas Infrared Survey. III. The H-band Imaging Survey and the Near-Infrared and Optical Photometric Catalogs (2001)

Chen, Hsiao-Wen, McCarthy, P. J., Marzke, R. O., Wilson, J., Carlberg, R. G., Firth, A. E., ...

(Abridged) The Las Campanas Infrared Survey, based on broad-band optical and near-infrared photometry, is designed to robustly identify a statistically significant and representative sample of...

The Las Campanas IR Survey: Early Type Galaxy Progenitors Beyond Redshift One (2001)

McCarthy, P. J., Carlberg, R. G., Marzke, R. O., Firth, A. E., Ellis, R. S., ...

(Abridged) We have identified a population of faint red galaxies from a 0.62 square degree region of the Las Campanas Infrared Survey whose properties are consistent with their being the progenitors...

On the 1/3 factor in the CMB Sachs-Wolfe effect (2001)

Hwang, J., Padmanabhan, T., Lahav, O., Noh, H.

We point out that a pseudo-Newtonian interpretations of the $(1/3)$ factor in the Sachs-Wolfe effect, which relates the fluctuations in temperature and potential, $(\delta T/ T) = (1/ 3) \delta...

The 2dF Galaxy Redshift Survey: Galaxy luminosity functions per spectral type (2001)

Madgwick, D. S., Lahav, O., Baldry, I. K., Baugh, C. M., Bland-Hawthorn, J., Bridges, T., ...

We calculate the optical bj luminosity function of the 2dF Galaxy Redshift Survey (2dFGRS) for different subsets defined by their spectral properties. These spectrally selected subsets are defined...

The 2dF Galaxy Redshift Survey: Spectra and redshifts (2001)

Colless, Matthew, Dalton, G. B., Maddox, S. J., Sutherland, W. J., Norberg, P., Cole, S., ...

The 2dF Galaxy Redshift Survey (2dFGRS) is designed to measure redshifts for approximately 250000 galaxies. This paper describes the survey design, the spectroscopic observations, the redshift...

The 2dF Galaxy Redshift Survey: The population of nearby radio galaxies at the 1 mJy level (2001)

Magliocchetti, M., Maddox, S. J., Jackson, C. A., Bland-Hawthorn, J., Bridges, T., Cannon, R., ...

We use redshift determinations and spectral analysis of galaxies in the 2dF Galaxy Redshift Survey to study the properties of local radio sources with $S\ge 1$ mJy. 557 objects drawn from the FIRST...

Radio sources in the 2dF Galaxy Redshift Survey - II. Local radio luminosity functions for AGN and star-forming galaxies at 1.4 GHz (2001)

Sadler, Elaine M., Jackson, Carole A., Cannon, Russell D., McIntyre, Vincent J., Murphy, Tara, Bland-Hawthorn, J., ...

We have cross-matched the 1.4 GHz NRAO VLA Sky Survey (NVSS) with the first 210 fields observed in the 2dF Galaxy Redshift Survey (2dFGRS), covering an effective area of 325 square degrees (about 20%...

The 2dF Galaxy Redshift Survey: Luminosity dependence of galaxy clustering (2001)

Norberg, P., Baugh, C. M., Hawkins, E., Maddox, S., Peacock, J. A., Cole, S., ...

We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of...

A measurement of the cosmological mass density from clustering in the 2dF Galaxy Redshift Survey (2001)

Peacock, J. A., Cole, S., Norberg, P., Baugh, C. M., Bland-Hawthorn, J., Bridges, T., ...

The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the universe. A key test of this...

A measurement of the cosmological mass density from clustering in the 2dF galaxy redshift survey. (2001)

Peacock, J. A., Cole, S., Norberg, P., Baugh, C. M., Bland-Hawthorn, J., Bridges, T., ...

The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the Universe. A key test of this...

Parameterisation of Galaxy Spectra in the 2dF Galaxy Redshift Survey (2000)

Madgwick, D., Lahav, O., Taylor, K.

The 2dF Galaxy Redshift Survey has already yielded over 130,000 galaxy spectra (out of the planned 250,000). We present a method for the parameterisation of galaxy spectra in the 2dF and other large...

Cosmological Parameters from Velocities, CMB and Supernovae (2000)

Bridle, S. L., Zehavi, I., Dekel, A., Lahav, O., Hobson, M. P., Lasenby, A. N.

We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8, from peculiar velocities, CMB and type Ia supernovae. These three data sets directly probe the mass...

Objective Classification of Galaxy Spectra using the Information Bottleneck Method (2000)

Slonim, N., Somerville, R., Tishby, N., Lahav, O.

A new method for classification of galaxy spectra is presented, based on a recently introduced information theoretical principle, the `Information Bottleneck'. For any desired number of classes,...

Bayesian `Hyper-Parameters' Approach to Joint Estimation: The Hubble Constant from CMB Measurements (1999)

Lahav, O., Bridle, S. L., Hobson, M. P., Lasenby, A. N., Sodr'e Jr., L.

Recently several studies have jointly analysed data from different cosmological probes with the motivation of estimating cosmological parameters. Here we generalise this procedure to take into...

The 2-10 keV XRB dipole and its cosmological implications (1999)

Scharf, C. A., Jahoda, K., Treyer, M., Lahav, O., Boldt, E., Piran, T.

The hard X-ray (>2 keV) emission of the local and distant Universe as observed with the HEAO1-A2 experiment is reconsidered in the context of large scale cosmic structure. Using all-sky X-ray samples...

Cosmological parameters from cluster abundances, CMB and IRAS (1999)

Bridle, S. L., Eke, V. R., Lahav, O., Lasenby, A. N., Hobson, M. P., Cole, S., ...

We combine information on cosmological parameters from cluster abundances, CMB primordial anisotropies and the IRAS 1.2 Jy galaxy redshift survey. We take as free parameters the present values of the...

The 2dF Galaxy Redshift Survey: Spectral Types and Luminosity Functions (1999)

Folkes, S. R., Ronen, S., Price, I., Lahav, O., Colless, M., Maddox, S. J., ...

We describe the 2dF Galaxy Redshift Survey (2dFGRS), and the current status of the observations. In this exploratory paper, we apply a Principal Component Analysis to a preliminary sample of 5869...

The Observed Evolution of Galaxy Clustering Vs. Epoch-Dependent Biasing Models (1999)

Magliocchetti, M., Bagla, J. S., Maddox, S. J., Lahav, O.

We study the observed evolution of galaxy clustering as a function of redshift. We find that the clustering of galaxies decreases as we go from observations of the local Universe to $z \sim 2$. On...

The Supergalactic Plane revisited with the Optical Redshift Survey (1998)

Lahav, O., Santiago, B. X., Webster, A. M., Strauss, M. A., Davis, M., Dressler, A., ...

We re-examine the existence and extent of the planar structure in the local galaxy density field, the so-called Supergalactic Plane (SGP). This structure is studied here in three dimensions using...

Constraints on the Clustering, Biasing and Redshift Distribution of Radio Sources (1998)

Magliocchetti, M., Maddox, S. J., Lahav, O., Wall, J. V.

We discuss how different theoretical predictions for the variance $\sigma^2$ of the distribution of radio sources can be matched to measurements from the FIRST survey at different flux limits. The...

Principal Component Analysis Of Synthetic Galaxy Spectra (1998)

Ronen, S., Aragon-Salamanca, A., Lahav, O.

We analyse synthetic galaxy spectra from the evolutionary models of Bruzual&Charlot and Fioc&Rocca-Volmerange using the method of Principal Component Analysis (PCA). We explore synthetic spectra with...

Variance and Skewness in the FIRST survey (1998)

Magliocchetti, M., Maddox, S. J., Lahav, O., Wall, J. V.

We investigate the large-scale clustering of radio sources in the FIRST 1.4-GHz survey by analysing the distribution function (counts in cells). We select a reliable sample from the the FIRST...

Galaxies Discovered Behind the Milky Way by the Dwingeloo Obscured Galaxies Survey (1997)

Henning, P. A., Kraan-Korteweg, R. C., Rivers, A. J., Loan, A. J., Lahav, O., Burton, W. B.

Our Galaxy blocks a significant portion of the extragalactic sky from view, hampering studies of large-scale structure. This produces an incomplete knowledge of the distribution of galaxies, and,...

The correlation function of radio sources (1996)

Loan, A. J., Wall, J. V., Lahav, O.

We investigate the large-scale clustering of radio sources in the Green Bank and Parkes-MIT-NRAO 4.85 GHz surveys by measuring the angular two-point correlation function w(\theta). Excluding...

An Artificial Neural Network Approach to Classification of Galaxy Spectra (1996)

Folkes, S. R., Lahav, O., Maddox, S. J.

We present a method for automated classification of galaxies with low signal-to-noise (S/N) spectra typical of redshift surveys. We develop spectral simulations based on the parameters for the 2dF...

What is a Peculiar Galaxy ? (1996)

Naim, A., Lahav, O.

Following the recent surge of interest in peculiar galaxies at high redshifts we consider the definition, or lack thereof, of morphological peculiarities on a sample of local universe galaxies....

The Two-Point Correlation Function And Morphological Segregation In The Optical Redshift Survey (1996)

Hermit Astronomical, S. Hermit, B. X. Santiago, O. Lahav, M. A. Strauss, M. Davis, ...

Introduction It is an important goal of astronomy to understand the formation of galaxies and large scale structure. One of the ways to constrain these models is by quantifying the clustering of the...

Faint Blue Galaxies as a Probe of the X-ray Background at High Redshift (1995)

Treyer, M. A., Lahav, O.

We present a formalism describing the physical content of cross-correlation functions between a diffuse background and a population of discrete sources. The formalism is used to interpret...

Neural computation as a tool for galaxy classification : methods and examples (1995)

Lahav, O., Naim, A., Sodre, L., Storrie-Lombardi, M. C.

We apply and compare various Artificial Neural Network (ANN) and other algorithms for automatic morphological classification of galaxies. The ANNs are presented here mathematically, as non-linear...

Visual Search for Galaxies near the Northern Crossing of the Supergalactic plane by the Milky Way (1995)

Hau, G. K. T., Ferguson, H. C., Lahav, O., Lynden-Bell, D.

We have visually examined twelve Palomar red Plates for galaxies at low Galactic latitude b, where the Supergalactic Plane (SGP) is crossed by the Galactic Plane (GP), at Galactic longitude l ~135...

AUTOMATED MORPHOLOGICAL CLASSIFICATION OF APM GALAXIES BY SUPERVISED ARTIFICIAL NEURAL NETWORKS (1995)

Naim, A., Lahav, O., Sodre Jr., L., Storrie-Lombardi, M. C.

We train Artificial Neural Networks to classify galaxies based solely on the morphology of the galaxy images as they appear on blue survey plates. The images are reduced and morphological features...

A COMPARATIVE STUDY OF MORPHOLOGICAL CLASSIFICATIONS OF APM GALAXIES (1995)

Naim, A., Lahav, O., Buta, R. J., Corwin Jr., H. G., De Vaucouleurs, G., Dressler, A., ...

We investigate the consistency of visual morphological classifications of galaxies by comparing classifications for 831 galaxies from six independent observers. The galaxies were classified on laser...

Galaxies, Human Eyes and Artificial Neural Networks (1994)

Lahav, O., Naim, A., Buta, R. J., Corwin, H. G., De Vaucouleurs, G., Dressler, A., ...

Quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. But galaxy morphological classification is still...

Nearby Galaxies and the Ginga X-ray Background (1994)

Carrera, F. J., Barcons, X., Butcher, J. A., Fabian, A. C., Lahav, O., Stewart, G. C., ...

We present here the results of cross-correlating the X-ray background measured by Ginga in the 2-10 keV band with several catalogues of extragalactic objects. Positive signals with an amplitude of a...

Wiener Reconstruction of The Large Scale Structure (1994)

Zaroubi, S., Hoffman, Y., Fisher, K. B., Lahav, O.

The formalism of Wiener filtering is developed here for the purpose of reconstructing the large scale structure of the universe from noisy, sparse and incomplete data. The method is based on a linear...

The Optical Redshift Survey: Sample Selection and the Galaxy Distribution (1994)

Santiago, B. X., Strauss, M. A., Lahav, O., Davis, M., Dressler, A., Huchra, J.

This is the first in a series of papers describing the {\it Optical Redshift Survey} (ORS), a redshift survey of optically selected galaxies covering 98\% of the sky above $|b| = 20^\circ$ (8.09...

Wiener Reconstruction of Galaxy Surveys in Spherical Harmonics (1993)

Lahav, O., Fisher, K. B., Hoffman, Y., Scharf, C. A., Zaroubi, S.

The analysis of whole-sky galaxy surveys commonly suffers from the problems of shot-noise and incomplete sky coverage (e.g. at the Zone of Avoidance). The orthogonal set of spherical harmonics is...

A seeded ambient temperature ferrite process for treatment of AMD waters: magnetite formation in the presence and absence of calcium ions under steady state operation (1970)

Morgan, B.E, Lahav, O., Loewenthal, R.E.

An ambient temperature ferrite process has been developed for the removal of iron and non-ferrous metals from AMD waters. The process involves the controlled formation of magnetite (Fe3O4) that has...

Measurement of pH, alkalinity and acidity in ultra-soft waters (1970)

Lahav, O, Morgan, BE

Conventional characterisation of low alkalinity waters via pH measurement and titration of total alkalinity to a prescribed end-point invariably leads to large errors. These errors result from...