Physical Sciences and Mathematics Commons^™

Galaxy And Mass Assembly (Gama) : The Stellar Mass Budget Of Galaxy Spheroids And Discs., Amanda J. Moffett, Rebecca Lange, Simon P. Driver, Aaron S. G. Robotham, Lee S. Kelvin, Mehmet Alpaslan, Stephen K. Andrews, Joss Bland-Hawthorn, Sarah Brough, Michelle E. Cluver, Matthew Colless, Luke J. M. Davies, Benne W. Holwerda, Andrew M. Hopkins, Prajwal R. Kafle, Jochen Liske, Martin Meyer

Faculty Scholarship

We build on a recent photometric decomposition analysis of 7506 Galaxy and Mass Assembly (GAMA) survey galaxies to derive stellar mass function fits to individual spheroid and disc component populations down to a lower mass limit of log(M*/M⊙) = 8. We find that the spheroid/disc mass distributions for individual galaxy morphological types are well described by single Schechter function forms. We derive estimates of the total stellar mass densities in spheroids (ρspheroid = 1.24 ± 0.49 × 108 M⊙ Mpc −3h0.7) and discs (ρdisc = 1.20 ± 0.45 × 108 M⊙ Mpc −3h0.7), which translates to approximately 50 …

Galaxy And Mass Assembly (Gama) : M–Re Relations Of Z = 0 Bulges, Discs And Spheroids., Rebecca Lange, Amanda J. Moffett, Simon P. Driver, Aaron S. G. Robotham, Claudia Del P. Lagos, Lee S. Kelvin, Christopher Conselice, Berta Margalef-Bentabol, Mehmet Alpaslan, Ivan K. Baldry, Joss Bland-Hawthorn, Malcolm Bremer, Sarah Brough, Michelle Cluver, Matthew Colless, Luke J. M. Davies, Boris Haußler, Benne W. Holwerda, Andrew M. Hopkins, Prajwal R. Kafle, Rebecca Kennedy, Jochen Liske, Steven Phillipps, Cristina C. Popescu, Edward N. Taylor, Richard Tuffs, Eelco Van Kampen, Angus H. Wright

Faculty Scholarship

We perform automated bulge + disc decomposition on a sample of ∼7500 galaxies from the Galaxy And Mass Assembly (GAMA) survey in the redshift range of 0.002 < z < 0.06 using Structural Investigation of Galaxies via Model Analysis, a wrapper around GALFIT3. To achieve robust profile measurements, we use a novel approach of repeatedly fitting the galaxies, varying the input parameters to sample a large fraction of the input parameter space. Using this method, we reduce the catastrophic failure rate significantly and verify the confidence in the fit independently of χ2. Additionally, using the median of the final fitting values and the 16th and 84th percentile produces more realistic error estimates than those provided by GALFIT, which are known to be underestimated. We use the results of our decompositions to analyse the stellar mass – half-light radius relations of bulges, discs and spheroids. We further investigate the association of components with a parent disc or elliptical relation to provide definite z = 0 disc and spheroid M–Re relations. We conclude by comparing our local disc and spheroid M–Re to simulated data from EAGLE and high-redshift data from Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey-Ultra Deep Survey. We show the potential of using the M–Re relation to study galaxy evolution in both cases but caution that for a fair comparison, all data sets need to be processed and analysed in the same manner.

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) : The Stellar Mass Budget By Galaxy Type., Amanda J. Moffett, Stephen A. Ingarfield, Simon P. Driver, Aaron S. G. Robotham, Lee S. Kelvin, Rebecca Lange, Uros Mestric, Mehmet Alpaslan, Ivan K. Baldry, Joss Bland-Hawthorn, Sarah Brough, Michelle Cluver, Luke J. M. Davies, Benne W. Holwerda, Andrew M. Hopkins, Prajwal R. Kafle, Rebecca Kennedy, Peder Norberg, Edward N. Taylor

Faculty Scholarship

We report an expanded sample of visual morphological classifications from the Galaxy and Mass Assembly survey phase two, which now includes 7556 objects (previously 3727 in phase one). We define a local (z < 0.06) sample and classify galaxies into E, S0-Sa, SB0-SBa, Sab-Scd, SBab-SBcd, Sd-Irr, and ‘little blue spheroid’ types. Using these updated classifications, we derive stellar mass function fits to individual galaxy populations divided both by morphological class and more general spheroid- or disc-dominated categories with a lower mass limit of log(M*/M⊙) = 8 (one dex below earlier morphological mass function determinations). We find that all individual morphological classes and the combined spheroid-/bulge-dominated classes are well described by single Schechter stellar mass function forms. We find that the total stellar mass densities for individual galaxy populations and for the entire galaxy population are bounded within our stellar mass limits and derive an estimated total stellar mass …

The Ghosts Survey – Ii. The Diversity Of Halo Colour And Metallicity Profiles Of Massive Disc Galaxies., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Jeremy Bailin, Roelof S. De Jong, Benne W. Holwerda, David Streich, Grace Silverstein

Faculty Scholarship

We study the stellar halo colour properties of six nearby massive highly inclined disc galaxies using Hubble space telescope Advanced Camera for Surveys and Wide Field Camera 3 observations in both F606W and F814W filters from the GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disks, and Star clusters) survey. The observed fields probe the stellar outskirts out to projected distances of ∼50–70 kpc from their galactic centre along the minor axis. The 50 per cent completeness levels of the colour–magnitude diagrams are typically at 2 mag below the tip of the red giant branch (RGB). We …

Extragalactic Archeology With The Ghosts Survey : I. Age-Resolved Disk Structure Of Nearby Low-Mass Galaxies., David Streich, Roelof S. De Jong, Jeremy Bailin, Eric F. Bell, Benne W. Holwerda, Ivan Minchev, Antonela Monachesi, David J. Radburn-Smith

Faculty Scholarship

Aims. We study the individual evolution histories of three nearby low-mass edge-on galaxies (IC 5052, NGC 4244, and NGC 5023).

Methods. Using resolved stellar populations, we constructed star count density maps for populations of different ages and analyzed the change of structural parameters with stellar age within each galaxy.

Results. We do not detect a separate thick disk in any of the three galaxies, even though our observations cover a wider range in equivalent surface brightness than any integrated light study. While scale heights increase with age, each population can be well described by a single disk. Two of the …