Physical Sciences and Mathematics Commons^™

Galaxy And Mass Assembly (Gama), U. Sureshkumar, A. Durkalec, A. Pollo, M. Bilicki, J. Loveday, D. J. Farrow, Benne Holwerda, A. M. Hopkins, J. Liske, K. A. Pimbblet, E. N. Taylor, A. H. Wright

Faculty Scholarship

Context. Galaxies are biased tracers of the underlying network of dark matter. The strength of this bias depends on various galaxy properties and on redshift. One of the methods used to study these dependences of the bias is measurement of galaxy clustering. Such studies are made using galaxy samples from various catalogues, which frequently bear their own problems related to sample selection methods. It is therefore crucial to understand how sample choice influences clustering measurements and which galaxy property is the most direct tracer of the galaxy environment.

Aims. We investigate how different galaxy properties, such as luminosities in the …

Galaxy And Mass Assembly (Gama): The Clustering Of Galaxy Groups, S D. Riggs, R W Y M Barbhuiyan, J Loveday, S Brough, Benne Holwerda, A M. Hopkins, S Phillipps

Faculty Scholarship

We explore the clustering of galaxy groups in the Galaxy and Mass Assembly (GAMA) survey to investigate the dependence of group bias and profile on separation scale and group mass. Due to the inherent uncertainty in estimating the group selection function, and hence the group autocorrelation function, we instead measure the projected galaxy–group cross-correlation function. We find that the group profile has a strong dependence on scale and group mass on scales r⊥≲1h−1" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; …

The Dependence Of Intrinsic Alignment Of Galaxies On Wavelength Using Kids And Gama, Christos Georgiou, Harry Johnston, Henk Hoekstra, Massimo Viola, Konrad Kuijken, Benjamin Joachimi, Nora Elisa Chisari, Daniel J. Farrow, Hendrik Hildebrandt, Benne W. Holwerda, Arun Kannawadi

Faculty Scholarship

The outer regions of galaxies are more susceptible to the tidal interactions that lead to intrinsic alignments of galaxies. The resulting alignment signal may therefore depend on the passband if the colours of galaxies vary spatially. To quantify this, we measured the shapes of galaxies with spectroscopic redshifts from the GAMA survey using deep gri imaging data from the KiloDegree Survey. The performance of the moment-based shape measurement algorithm DEIMOS was assessed using dedicated image simulations, which showed that the ellipticities could be determined with an accuracy better than 1% in all bands. Additional tests for potential systematic errors did …

Testing For Directionality In The Planck Polarization And Lensing Data, Majd Ghrear, Emory F. Bunn, Dagoberto Contreras, Douglas Scott

Physics Faculty Publications

In order to better analyse the polarization of the cosmic microwave background (CMB), which is dominated by emission from our Galaxy, we need tools that can detect residual foregrounds in cleaned CMB maps. Galactic foregrounds introduce statistical anisotropy and directionality to the polarization pseudo-vectors of the CMB, which can be investigated by using the D statistic of Bunn and Scott. This statistic is rapidly computable and capable of investigating a broad range of data products for directionality. We demonstrate the application of this statistic to detecting foregrounds in polarization maps by analysing the uncleaned Planck 2018 frequency maps. For the …

Galaxy And Mass Assembly (Gama) : Fine Filaments Of Galaxies Detected Within Voids., Mehmet Alpaslan, Aaron S. G. Robotham, Danail Obreschkow, Samantha Penny, Simon Driver, Peder Norberg, Sarah Brough, Michael Brown, Michelle Cluver, Benne W. Holwerda, Andrew M. Hopkins, Eelco Van Kampen, Lee S. Kelvin, Maritza A. Lara-Lopez, Jochen Liske, Jon Loveday, Smriti Mahajan, Kevin Pimbblet

Benne Holwerda

Based on data from the Galaxy and Mass Assembly (GAMA) survey, we report on the discovery of structures that we refer to as ‘tendrils’ of galaxies: coherent, thin chains of galaxies that are rooted in filaments and terminate in neighbouring filaments or voids. On average, tendrils contain six galaxies and span 10 h−1 Mpc. We use the so-called line correlation function to prove that tendrils represent real structures rather than accidental alignments. We show that voids found in the Sloan Digital Sky Survey, 7th data release survey that overlap with GAMA regions contain a large number of galaxies, primarily belonging …

Dependence Of Gama Galaxy Halo Masses On The Cosmic Web Environment From 100 Deg2 Of Kids Weak Lensing Data., Margot M. Brouwer, Marcello Cacciato, Andrej Dvornik, Lizzie Eardley, Catherine Heymans, Henk Hoekstra, Konrad Kuijken, Tamsyn Mcnaught-Roberts, Cristobal Sifon, Massimo Viola, Mehmet Alpaslan, Maciej Bilicki, Joss Bland-Hawthorn, Sarah Brough, Ami Choi, Simon P. Driver, Thomas Erben, Aniello Grado, Hendrik Hildebrandt, Benne W. Holwerda, Andrew M. Hopkins, Jelte T. A. De Jong, Jochen Liske, John Mcfarland, Reiko Nakajima, Nicola R. Napolitano, Peder Norberg, John A. Peacock, Mario Radovich, Aaron S. G. Robotham, Peter Schneider, Gert Sikkema, Edo Van Uitert, Gijs Verdoes Kleijn, Edwin A. Valentijn

Benne Holwerda

Galaxies and their dark matter haloes are part of a complex network of mass structures, collectively called the cosmic web. Using the tidal tensor prescription these structures can be classified into four cosmic environments: voids, sheets, filaments and knots. As the cosmic web may influence the formation and evolution of dark matter haloes and the galaxies they host, we aim to study the effect of these cosmic environments on the average mass of galactic haloes. To this end we measure the galaxy–galaxy lensing profile of 91 195 galaxies, within 0.039 < z < 0.263, from the spectroscopic Galaxy And Mass Assembly survey, using ∼100deg2" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">∼100deg2∼100deg2 of overlapping data from the Kilo-Degree Survey. In each …

Galaxy And Mass Assembly (Gama): Stellar Mass Growth Of Spiral Galaxies In The Cosmic Web., Mehmet Alpaslan, Meiert Grootes, Pamela M. Marcum, Cristina C. Popescu, Richard Tuffs, Joss Bland-Hawthorn, Sarah Brough, Michael J. I. Brown, Luke J. M. Davies, Simon P. Driver, Benne W. Holwerda, Lee S. Kelvin, Maritza A. Lara-Lopez, Angel R. Lopez-Sanchez, Jon Loveday, Amanda J. Moffett, Edward N. Taylor, Matt S. Owers, Aaron S. G. Robotham

Benne Holwerda

We look for correlated changes in stellar mass and star formation rate (SFR) along filaments in the cosmic web by examining the stellar masses and UV-derived SFRs of 1799 ungrouped and unpaired spiral galaxies that reside in filaments. We devise multiple distance metrics to characterize the complex geometry of filaments, and find that galaxies closer to the cylindrical centre of a filament have higher stellar masses than their counterparts near the periphery of filaments, on the edges of voids. In addition, these peripheral spiral galaxies have higher SFRs at a given mass. Complementing our sample of filament spiral galaxies with …

Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., C. Gheller, F. Vazza, M. Brüggen, M. Alpaslan, Benne W. Holwerda

Benne Holwerda

Despite containing about a half of the total matter in the Universe, at most wavelengths the filamentary structure of the cosmic web is difficult to observe. In this work, we use large unigrid cosmological simulations to investigate how the geometrical, thermodynamical and magnetic properties of cosmological filaments vary with mass and redshift (z ≤ 1). We find that the average temperature, length, volume and magnetic field of filaments scales well with their total mass. This reflects the role of self-gravity in shaping their properties and enables statistical predictions of their observational properties based on their mass. We also focus on …

Dependence Of Gama Galaxy Halo Masses On The Cosmic Web Environment From 100 Deg2 Of Kids Weak Lensing Data., Margot M. Brouwer, Marcello Cacciato, Andrej Dvornik, Lizzie Eardley, Catherine Heymans, Henk Hoekstra, Konrad Kuijken, Tamsyn Mcnaught-Roberts, Cristobal Sifon, Massimo Viola, Mehmet Alpaslan, Maciej Bilicki, Joss Bland-Hawthorn, Sarah Brough, Ami Choi, Simon P. Driver, Thomas Erben, Aniello Grado, Hendrik Hildebrandt, Benne W. Holwerda, Andrew M. Hopkins, Jelte T. A. De Jong, Jochen Liske, John Mcfarland, Reiko Nakajima, Nicola R. Napolitano, Peder Norberg, John A. Peacock, Mario Radovich, Aaron S. G. Robotham, Peter Schneider, Gert Sikkema, Edo Van Uitert, Gijs Verdoes Kleijn, Edwin A. Valentijn

Faculty Scholarship

Galaxies and their dark matter haloes are part of a complex network of mass structures, collectively called the cosmic web. Using the tidal tensor prescription these structures can be classified into four cosmic environments: voids, sheets, filaments and knots. As the cosmic web may influence the formation and evolution of dark matter haloes and the galaxies they host, we aim to study the effect of these cosmic environments on the average mass of galactic haloes. To this end we measure the galaxy–galaxy lensing profile of 91 195 galaxies, within 0.039 < z < 0.263, from the spectroscopic Galaxy And Mass Assembly survey, using ∼100deg2" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">∼100deg2∼100deg2

of overlapping data from the Kilo-Degree Survey. In …

Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., C. Gheller, F. Vazza, M. Bruggen, M. Alpaslan, Benne W. Holwerda, A. M. Hopkins, J. Liske

Faculty Scholarship

Despite containing about a half of the total matter in the Universe, at most wavelengths the filamentary structure of the cosmic web is difficult to observe. In this work, we use large unigrid cosmological simulations to investigate how the geometrical, thermodynamical and magnetic properties of cosmological filaments vary with mass and redshift (z ≤ 1). We find that the average temperature, length, volume and magnetic field of filaments scales well with their total mass. This reflects the role of self-gravity in shaping their properties and enables statistical predictions of their observational properties based on their mass. We also focus on …

Galaxy And Mass Assembly (Gama): Stellar Mass Growth Of Spiral Galaxies In The Cosmic Web., Mehmet Alpaslan, Meiert Grootes, Pamela M. Marcum, Cristina C. Popescu, Richard Tuffs, Joss Bland-Hawthorn, Sarah Brough, Michael J. I. Brown, Luke J. M. Davies, Simon P. Driver, Benne W. Holwerda, Lee S. Kelvin, Maritza A. Lara-Lopez, Angel R. Lopez-Sanchez, Jon Loveday, Amanda J. Moffett, Edward N. Taylor, Matt S. Owers, Aaron S. G. Robotham

Faculty Scholarship

We look for correlated changes in stellar mass and star formation rate (SFR) along filaments in the cosmic web by examining the stellar masses and UV-derived SFRs of 1799 ungrouped and unpaired spiral galaxies that reside in filaments. We devise multiple distance metrics to characterize the complex geometry of filaments, and find that galaxies closer to the cylindrical centre of a filament have higher stellar masses than their counterparts near the periphery of filaments, on the edges of voids. In addition, these peripheral spiral galaxies have higher SFRs at a given mass. Complementing our sample of filament spiral galaxies with …

Galaxy And Mass Assembly (Gama) : Fine Filaments Of Galaxies Detected Within Voids., Mehmet Alpaslan, Aaron S. G. Robotham, Danail Obreschkow, Samantha Penny, Simon Driver, Peder Norberg, Sarah Brough, Michael Brown, Michelle Cluver, Benne W. Holwerda, Andrew M. Hopkins, Eelco Van Kampen, Lee S. Kelvin, Maritza A. Lara-Lopez, Jochen Liske, Jon Loveday, Smriti Mahajan, Kevin Pimbblet

Faculty Scholarship

Based on data from the Galaxy and Mass Assembly (GAMA) survey, we report on the discovery of structures that we refer to as ‘tendrils’ of galaxies: coherent, thin chains of galaxies that are rooted in filaments and terminate in neighbouring filaments or voids. On average, tendrils contain six galaxies and span 10 h−1 Mpc. We use the so-called line correlation function to prove that tendrils represent real structures rather than accidental alignments. We show that voids found in the Sloan Digital Sky Survey, 7th data release survey that overlap with GAMA regions contain a large number of galaxies, primarily belonging …

The Stellar Mass--Halo Mass Relation From Galaxy Clustering In Vuds: A High Star Formation Efficiency At Z≃3, A. Durkalec, O. Le Fevre, S. De La Torre, A. Pollo, P. Cassata, B. Garilli, V. Le Brun, B.C. Lemaux, D. Maccagni, L. Pentericci, L.A.M. Tasca, R. Thomas, E. Vanzella, G. Zamorani, E. Zucca, R. Amorin, S. Bardelli, L.P. Cassara, M. Castellano, A. Cimatti, O. Cucciati, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, S. Paltani, B. Ribeiro, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, L. Tresse, D. Vergani, P. Capak, S. Charlot, T. Contini, J.G. Cuby, J. Dunlop, S. Fotopoulou, A. Koekemoer, C. Lopez-Sanjuan, Y. Mellier, J. Pforr, M. Salvato, N. Scoville, Y. Taniguchi, P.W. Wang

Mauro Giavalisco

The relation between the galaxy stellar mass M⋆ and the dark matter halo mass Mh gives important information on the efficiency in forming stars and assembling stellar mass in galaxies. We present measurements of the ratio of stellar mass to halo mass (SMHR) at redshifts 2 < z < 5, obtained from the VIMOS Ultra Deep Survey. We use halo occupation distribution (HOD) modelling of clustering measurements on ~3000 galaxies with spectroscopic redshifts to derive the dark matter halo mass Mh, and spectral energy density fitting over a large set of multi-wavelength data to derive the stellar mass M⋆ and compute the SMHR = M⋆/Mh. We find that the SMHR ranges from 1% to 2.5% for galaxies with M⋆ = 1.3 × 109 M⊙ to M⋆ = 7.4 × 109 M⊙ in DM halos with Mh = 1.3 × 1011 M⊙ to Mh = 3 × 1011 M⊙. We derive the integrated star formation efficiency (ISFE) of these galaxies and find that the star formation efficiency is a moderate 6−9% for lower mass galaxies, while it is relatively high at 16% for galaxies with the median stellar mass of the sample ~ 7 × 109 M⊙. The lower ISFE at lower masses may indicate that some efficient means of suppressing star formation is at work (like SNe feedback), while the high ISFE for the average galaxy at z ~ 3 indicates that these galaxies efficiently build up their stellar mass at a key epoch in the mass assembly process. Based on our results, we propose a possible scenario in which the average massive galaxy at z ~ 3 begins to experience truncation of its star formation within a few million years.

The X-Ray Properties Of Optically Selected Clusters Of Galaxies, A. K. Hicks, G. W. Pratt, M. Donahue, E. Ellingson, M. Gladders, H. Böhringer, H. K. C. Yee, Renbin Yan, J. H. Croston, D. G. Gilbank

Physics and Astronomy Faculty Publications

We present the results of Chandra and Suzaku X-ray observations of nine moderate-redshift (0.16 < z < 0.42) clusters discovered via the Red-sequence Cluster Survey (RCS). Surface brightness profiles are fitted to β-models, gas masses are determined, integrated spectra are extracted within R₂₅₀₀, and X-ray temperatures and luminosities are inferred. TheL_X–T_X relationship expected from self-similar evolution is tested by comparing this sample to our previous X-ray investigation of nine high-redshift (0.6 < z < 1.0) optically selected clusters. We find that optically selected clusters are systematically less luminous than X-ray selected clusters of similar X-ray temperature at both moderate and high z. We are unable to constrain evolution in the L_X–T_X relation with these data, but find it consistent with no evolution, within relatively large uncertainties. To investigate selection effects, we compare the X-ray properties of our sample to those of clusters in the …

The Vlt Lbg Redshift Survey I: Clustering And Dynamics Of ≈ 1000 Galaxies At Z ≈ 3⋆, R. M. Bielby, T. Shanks, P. M. Weilbacher, L. Infante, N. H.M. Crighton, C. Bornancini, N. Bouché, P. Héraudeau, D. G. Lambas, James D. Lowenthal, D. Minniti, N. Padilla, P. Petitjean, T. Theuns

Astronomy: Faculty Publications

We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five ≈36 × 36 arcmin fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing ≈210002 < z < 3.5 galaxy candidates to be selected using the Lyman-break technique. We performed spectroscopic follow-up using VLT VIMOS, measuring redshifts for 1020 z > 2 Lyman-break galaxies and 10 z > 2 QSOs from a total of 19 VIMOS pointings. From the galaxy spectra, we observe a 625 ± 510kms velocity offset between the interstellar absorption and Lyman α emission-line redshifts, consistent with previous results. Using the photometric and spectroscopic catalogues, we have analysed the galaxy clustering at z≈ 3. The angular correlation …

Pre-Heating By Pre-Virialization And Its Impact On Galaxy Formation, Hj Mo, Xh Yang, Fc Van Den Bosch, N Katz, I Zehavi, T Tripp, Dv Bowen, Kr Sembach, Eb Jenkins, Bd Savage, P Richter

Astronomy Department Faculty Publication Series

We use recent observations of the H i mass function to constrain galaxy formation. The data conflict with the standard model where most of the gas in a low-mass dark matter halo is assumed to settle into a disc of cold gas that is depleted by star formation and supernova-driven outflows until the disc becomes gravitationally stable. Assuming a star formation threshold density supported by both theory and observations, this model predicts H i masses that are much too large. The reason is simple: supernova feedback requires star formation, which in turn requires a high surface density for the gas. …

Ly Alpha Flux Power Spectrum And Its Covariance, H Zhan, R Dave, D Eisenstein, N Katz

Astronomy Department Faculty Publication Series

We analyse the flux power spectrum and its covariance using simulated Lyα forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm–hot intergalactic medium. Hence, to use the low-redshift Lyα flux power spectrum to constrain cosmology, one would need realistic hydrodynamical simulations. By comparing (one-dimensional) mass statistics with flux statistics, we show that the non-linear transform between density and flux quenches the fluctuations so that the flux power spectrum is much …

Properties Of Galaxy Clusters: Mass And Correlation Functions, F Governato, A Babul, T Quinn, P Tozzi, Cm Baugh, N Katz, G Lake

Astronomy Department Faculty Publication Series

We analyse parallel N-body simulations of three cold dark matter (CDM) universes to study the abundance and clustering of galaxy clusters. The simulation boxes are 500 h⁻¹ Mpc on a side and cover a volume comparable to that of the forthcoming Sloan Digital Sky Survey. The use of a treecode algorithm and 47 million particles allows us at the same time to achieve high mass and force resolution. We are thus able to make robust measurements of cluster properties with good number statistics up to a redshift larger than unity. We extract haloes using two independent, public domain …