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Astrophysics and Astronomy Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Louisville

2016

Galaxies: formation

Articles 1 - 4 of 4

Full-Text Articles in Astrophysics and Astronomy

The Bright End Of The Z~9 And Z~10 Uv Luminosity Functions Using All Five Candels Fields., R. J. Bouwens, P. A. Oesch, I. Labbe, G. D. Illingworth, G. G. Fazio, D. Coe, Benne W. Holwerda, R. Smit, M. Stefanon, P. G. Van Dokkum, M. Trenti, M. L. N. Ashby, J. S. Huang, L. Spitler, C. Straatman, L. Bradley, D. Magee Oct 2016

The Bright End Of The Z~9 And Z~10 Uv Luminosity Functions Using All Five Candels Fields., R. J. Bouwens, P. A. Oesch, I. Labbe, G. D. Illingworth, G. G. Fazio, D. Coe, Benne W. Holwerda, R. Smit, M. Stefanon, P. G. Van Dokkum, M. Trenti, M. L. N. Ashby, J. S. Huang, L. Spitler, C. Straatman, L. Bradley, D. Magee

Faculty Scholarship

The deep, wide-area (∼800–900 arcmin2 ) near-infrared/WFC3/IR + Spitzer/IRAC observations over the CANDELS fields have been a remarkable resource for constraining the bright end of high-redshift UV luminosity functions. However, the lack of Hubble Space Telescope (HST) 1.05 μm observations over the CANDELS fields has made it difficult to identify z ∼ 9–10 sources robustly, since such data are needed to confirm the presence of an abrupt Lyman break at 1.2 μm. Here, we report on the successful identification of many such z ∼ 9–10 sources from a new HST program (z9-CANDELS) that targets the highest-probability z ∼ 9–10 galaxy …


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 Oct 2016

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) : Galaxy Colour Gradients Versus Colour, Structure, And Luminosity., Rebecca Kennedy, Steven P. Bamford, Boris Haußler, Sarah Brough, Benne W. Holwerda, Andrew M. Hopkins, Marina Vika, Benedetta Vulcani Sep 2016

Galaxy And Mass Assembly (Gama) : Galaxy Colour Gradients Versus Colour, Structure, And Luminosity., Rebecca Kennedy, Steven P. Bamford, Boris Haußler, Sarah Brough, Benne W. Holwerda, Andrew M. Hopkins, Marina Vika, Benedetta Vulcani

Faculty Scholarship

Using single-component fits to SDSS/UKIDSS images of galaxies in the G09 region of the GAMA survey we study radial colour gradients across the galaxy population. We use the multi-wavelength information provided by MegaMorph analysis of galaxy light profiles to calculate intrinsic colour gradients, and divide into six subsamples split by overall Sérsic index (n) and galaxy colour. We find a bimodality in the colour gradients of high- and low-n galaxies in all wavebands which varies with overall galaxy luminosity. Global trends in colour gradients therefore result from combining the contrasting behaviour of a number of different galaxy populations. The ubiquity …


Galaxy And Mass Assembly (Gama) : Understanding The Wavelength Dependence Of Galaxy Structure With Bulge-Disc Decompositions., Rebecca Kennedy, Steven P. Bamford, Boris Haußler, Ivan K. Baldry, Malcolm Bremer, Sarah Brough, Michael J. I. Brown, Simon P. Driver, Kenneth Duncan, Alister W. Graham, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Steven Phillipps, Marina Vika, Benedetta Vulcani Aug 2016

Galaxy And Mass Assembly (Gama) : Understanding The Wavelength Dependence Of Galaxy Structure With Bulge-Disc Decompositions., Rebecca Kennedy, Steven P. Bamford, Boris Haußler, Ivan K. Baldry, Malcolm Bremer, Sarah Brough, Michael J. I. Brown, Simon P. Driver, Kenneth Duncan, Alister W. Graham, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Steven Phillipps, Marina Vika, Benedetta Vulcani

Faculty Scholarship

With a large sample of bright, low-redshift galaxies with optical–near-IR imaging from the GAMA survey we use bulge-disc decompositions to understand the wavelength-dependent behaviour of single-Sérsic structural measurements. We denote the variation in single-Sérsic index with wavelength as N N , likewise for effective radius we use R R . We find that most galaxies with a substantial disc, even those with no discernable bulge, display a high value of N N . The increase in Sérsic index to longer wavelengths is therefore intrinsic to discs, apparently resulting from radial variations in stellar population and/or dust reddening. Similarly, low values …