MegaMorph – multiwavelength measurement of galaxy structure. Sérsic profile fits to galaxies near and far

Vika, Marina; Bamford, Steven P.; Häußler, Boris; Rojas, A.; Borch, Andrea; Nichol, R. C.

doi:10.1093/mnras/stt1320

Cited by 117 publications

(145 citation statements)

References 79 publications

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“…Indeed, we adopt this interpretation in Häußler et al (2013); Vika et al (2013);Vulcani et al (2014). With our bulgedisk decompositions, we are now in a position to test this.…”

Section: Bulge-to-totalmentioning

confidence: 71%

“…Driven by a determination to make more effective use of the multi-wavelength imaging available from modern surveys, the MegaMorph project Vika et al 2013 and Bamford, in prep.) developed and tested a new version of two-dimensional photometric analysis which constrains a single, wavelength-dependent model using multiple images simultaneously.…”

Section: Introductionmentioning

confidence: 99%

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MegaMorph – multiwavelength measurement of galaxy structure: physically meaningful bulge–disc decomposition of galaxies near and far

Vika

Bamford

Häußler

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Bulge-disc decomposition is a valuable tool for understanding galaxies. However, achieving robust measurements of component properties is difficult, even with high quality imaging, and it becomes even more so with the imaging typical of large surveys.In this paper we consider the advantages of a new, multi-band approach to galaxy fitting. We perform automated bulge-disc decompositions for 163 nearby galaxies, by simultaneously fitting multiple images taken in five photometric filters. We show that we are able to recover structural measurements that agree well with various other works, and confirm a number of key results. We additionally use our results to illustrate the link between total Sérsic index and bulge-disc structure, and demonstrate that the visually classification of lenticular galaxies is strongly dependent on the inclination of their disc component.By simulating the same set of galaxies as they would appear if observed at a range of redshifts, we are able to study the behaviour of bulge-disc decompositions as data quality diminishes. We examine how our multi-band fits perform, and compare to the results of more conventional, single-band methods. Multi-band fitting improves the measurement of all parameters, but particularly the bulge-to total flux ratio and component colours. We therefore encourage the use of this approach with future surveys.

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“…Indeed, we adopt this interpretation in Häußler et al (2013); Vika et al (2013);Vulcani et al (2014). With our bulgedisk decompositions, we are now in a position to test this.…”

Section: Bulge-to-totalmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

MegaMorph – multiwavelength measurement of galaxy structure: physically meaningful bulge–disc decomposition of galaxies near and far

Vika

Bamford

Häußler

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…(e.g., Häußler et al 2013;Vika et al 2013Vika et al , 2014. Vulcani et al (2014) have reported that n tends to be larger in redder bands for blue galaxies due to a bulge component with old stellar ages and/or dust attenuation at the central region.…”

Section: Statistical Difference and Selection Biasmentioning

confidence: 99%

MORPHOLOGIES OF ∼190,000 GALAXIES AT z = 0–10 REVEALED WITH HST LEGACY DATA. I. SIZE EVOLUTION

Shibuya

Ouchi

Harikane

2015

ApJS

397

122

511

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We present redshift evolution of galaxy effective radius r e obtained from the Hubble Space Telescope (HST) samples of ∼ 190, 000 galaxies at z = 0 − 10. Our HST samples consist of 176, 152 photo-z galaxies at z = 0 − 6 from the 3D-HST+CANDELS catalogue and 10, 454 Lyman break galaxies (LBGs) at z = 4 − 10 identified in CANDELS, HUDF09/12, and HFF parallel fields, providing the largest data set to date for galaxy size evolution studies. We derive r e with the same technique over the wide-redshift range of z = 0 − 10, evaluating the optical-to-UV morphological K-correction and the selection bias of photo-z galaxies+LBGs as well as the cosmological surface brightness dimming effect. We find that r e values at a given luminosity significantly decrease towards high-z, regardless of statistics choices (e.g. r e ∝ (1 + z) −1.10±0.06 for median). For star-forming galaxies, there is no evolution of the power-law slope of the size-luminosity relation and the median Sérsic index (n ∼ 1.5). Moreover, the r e -distribution is well represented by log-normal functions whose standard deviation σ ln re does not show significant evolution within the range of σ ln re ∼ 0.45 − 0.75. We calculate the stellar-to-halo size ratio from our r e measurements and the dark-matter halo masses estimated from the abundance matching study, and obtain a nearly constant value of r e /r vir = 1.0 − 3.5% at z = 0 − 8. The combination of the r e -distribution shape+standard deviation, the constant r e /r vir , and n ∼ 1.5 suggests a picture that typical high-z star-forming galaxies have disk-like stellar components in a sense of dynamics and morphology over cosmic time of z ∼ 0 − 6. If high-z star-forming galaxies are truly dominated by disks, the r e /r vir value and the disk formation model indicate that the specific angular momentum of the disk normalized by the host halo is j d /m d ≃ 0.5 − 1. These are statistical results for galaxies' major stellar components, and the detailed study of clumpy sub-components is presented in the paper II.

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“…The impact of the PSF is taken into account to deliver PSF-free galaxy models as well as possible (e.g. Simard et al 2002;Peng et al 2011;Vika et al 2013). Nevertheless, the choice of the analytical functions is somewhat arbitrary and does not necessarily apply to all galaxies.…”

Section: Image Deconvolutionmentioning

confidence: 99%

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

Cantale

Jablonka

Courbin

et al. 2016

A&A

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We present a detailed study of the colours of late-type galaxy discs for ten of the EDisCS galaxy clusters with 0.5 z 0.8. Our cluster sample contains 172 spiral galaxies, and our control sample is composed of 96 field disc galaxies. We deconvolved their ground-based V and I images obtained with FORS2 at the VLT with initial spatial resolutions between 0.4 and 0.8 arcsec to achieve a final resolution of 0.1 arcsec with 0.05 arcsec pixels, which is close to the resolution of the ACS at the HST. After removing the central region of each galaxy to avoid pollution by the bulges, we measured the V − I colours of the discs. We find that 50% of cluster spiral galaxies have disc V − I colours redder by more than 1σ of the mean colours of their field counterparts. This is well above the 16% expected for a normal distribution centred on the field disc properties. The prominence of galaxies with red discs depends neither on the mass of their parent cluster nor on the distance of the galaxies to the cluster cores. Passive spiral galaxies constitute 20% of our sample. These systems are not abnormally dusty. They are are made of old stars and are located on the cluster red sequences. Another 24% of our sample is composed of galaxies that are still active and star forming, but less so than galaxies with similar morphologies in the field. These galaxies are naturally located in the blue sequence of their parent cluster colour-magnitude diagrams. The reddest of the discs in clusters must have stopped forming stars more than ∼5 Gyr ago. Some of them are found among infalling galaxies, suggesting preprocessing. Our results confirm that galaxies are able to continue forming stars for some significant period of time after being accreted into clusters, and suggest that star formation can decline on seemingly long (1 to 5 Gyr) timescales.

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MegaMorph – multiwavelength measurement of galaxy structure. Sérsic profile fits to galaxies near and far

Cited by 117 publications

References 79 publications

MegaMorph – multiwavelength measurement of galaxy structure: physically meaningful bulge–disc decomposition of galaxies near and far

MegaMorph – multiwavelength measurement of galaxy structure: physically meaningful bulge–disc decomposition of galaxies near and far

MORPHOLOGIES OF ∼190,000 GALAXIES AT z = 0–10 REVEALED WITH HST LEGACY DATA. I. SIZE EVOLUTION

Disc colours in field and cluster spiral galaxies at 0.5 ≲z≲ 0.8

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