Deconvolution with Correct Sampling

Magain, Pierre; Courbin, F.; Sohy, Sandrine

doi:10.1086/305187

Cited by 219 publications

(244 citation statements)

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“…We used an improved version of the MCS image deconvolution algorithm (Magain et al 1998), because sampled images cannot be fully deconvolved without violating the sampling theorem. Instead, the images are partially deconvolved, meaning that we aim at an improved instead of an infinite resolution.…”

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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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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“…Stetson, Davis & Crabtree 1990;Magain, Courbin & Sohy 1998;Lupton et al 2001;Koptelova et al 2005). The majority of these methods requires the assumption of PSF invariance over the frame.…”

Section: T H E a Da P T I V E P S F -F I T T I N G P H Oto M E T R I mentioning

confidence: 99%

Adaptive PSF fitting – a highly performing photometric method and light curves of the GLS H1413+117: time delays and micro-lensing effects

Akhunov

Wertz

Elyiv

et al. 2016

Mon. Not. R. Astron. Soc.

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We present new photometric observations of H1413+117 acquired during seasons between 2001 and 2008 in order to estimate the time delays between the lensed quasar images and to characterize at best the on-going micro-lensing events. We propose a highly performing photometric method called the adaptive point spread function fitting and have successfully tested this method on a large number of simulated frames. This has enabled us to estimate the photometric error bars affecting our observational results. We analysed the V-and R-band light curves and V-R colour variations of the A-D components which show short-and long-term brightness variations correlated with colour variations. Using the χ 2 and dispersion methods, we estimated the time delays on the basis of the R-band light curves over the seasons between 2003 and 2006. We have derived the new values: t AB = −17.4 ± 2.1, t AC = −18.9 ± 2.8 and t AD = 28.8 ± 0.7 d using the χ 2 method (B and C are leading, D is trailing) with 1σ confidence intervals. We also used available observational constraints (resp. the lensed image positions, the flux ratios in mid-IR and two sets of time delays derived in the present work) to update the lens redshift estimation. We obtained z l = 1.95 +0.06 −0.10 which is in good agreement with previous estimations. We propose to characterize two kinds of micro-lensing events: micro-lensing for the A,

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“…For a first approach to what kind of disk could produce the PSFblurred images that are observed, we deconvolved them using different methods: (1) a classical reverse Fourier transformation (FT) with Wiener-Kolmogorov filtering (Kolmogorov 1941;Wiener 1949) of the noise, (2) an FT-based van Cittert scheme, (3) the MCS code (Magain et al 1998), and (4) a RichardsonLucy (R-L) scheme (Richardson 1972;Lucy 1974). In Cols.…”

Section: Deconvolutionmentioning

confidence: 99%

Modelling the huge,Herschel-resolved debris ring around HD 207129

Löhne

Augereau

Ertel

et al. 2012

A&A

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124

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Debris disks, which are inferred from the observed infrared excess to be ensembles of dust, rocks, and probably planetesimals, are common features of stellar systems. As the mechanisms of their formation and evolution are linked to those of planetary bodies, they provide valuable information. The few well-resolved debris disks are even more valuable because they can serve as modelling benchmarks and help resolve degeneracies in modelling aspects such as typical grain sizes and distances. Here, we present an analysis of the HD 207129 debris disk, based on its well-covered spectral energy distribution and Herschel/PACS images obtained in the framework of the DUNES (DUst around NEarby Stars) programme. We use an empirical power-law approach to the distribution of dust and we then model the production and removal of dust by means of collisions, direct radiation pressure, and drag forces. The resulting best-fit model contains a total of nearly 10 −2 Earth masses in dust, with typical grain sizes in the planetesimal belt ranging from 4 to 7 µm. We constrain the dynamical excitation to be low, which results in very long collisional lifetimes and a drag that notably fills the inner gap, especially at 70 µm. The radial distribution stretches from well within 100 AU in an unusual, outward-rising slope towards a rather sharp outer edge at about 170-190 AU. The inner edge is therefore smoother than that reported for Fomalhaut, but the contribution from the extended halo of barely bound grains is similarly small. Both slowly self-stirring and planetary perturbations could potentially have formed and shaped this disk.

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Deconvolution with Correct Sampling

Cited by 219 publications

References 10 publications

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

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

Adaptive PSF fitting – a highly performing photometric method and light curves of the GLS H1413+117: time delays and micro-lensing effects

Modelling the huge,Herschel-resolved debris ring around HD 207129

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