&lt;title&gt;Long-wavelength scattered-light halos in ASC CCDs&lt;/title&gt;

Sirianni, M.; Clampin, Mark; Hartig, G.; Rafal, Marc D.; Ford, H. C.; Golimowski, D. A.; Tremonti, Christy; Illingworth, G. D.; Blouke, Morley M.; Lesser, Michael P.; Burmester, William; Kimble, Randy A.; Sullivan, Pamela C.; Krebs, Carolyn A.; Yagelowicz, John

doi:10.1117/12.316832

Cited by 24 publications

(9 citation statements)

References 3 publications

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“…5 for n = 3.0 and r e > ∼ 1 for n = 4.0. In contrast, because of the red-halo effect (Sirianni et al 1998), r 110 moves inwards to shorter radii with the more strongly scattering PSF i,0m (Fig. 5c).…”

Section: About Analyses Of Galaxy Structures That Are Fitted With Sérmentioning

confidence: 95%

“…The PSFs used in this study should describe both temporal variations and the red-halo effect in the i band (as described by Sirianni et al 1998), and they should extend out to r 900 . As in Paper I, I chose to use the only published extended PSFs of M02, which were measured with both the (Cousins) V and the (Gunn) i bands, at two distinct occasions separated by three months: PSF V,0m and PSF i,0m were measured three months before PSF V,3m and PSF i,3m .…”

Section: Choosing Representative Psfsmentioning

confidence: 99%

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The influence of diffuse scattered light

Sandín

2015

A&A

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Studies of deep photometry of galaxies have presented discoveries of excess light in surface-brightness and colour profiles at large radii in the form of diffuse faint haloes and thick discs. In a majority of the cases, it has seemed necessary to use exotic stellar populations or alternative physical solutions to explain the excess. Few studies have carefully scrutinized the role of scattered light in this context. I explore the influence of scattered light on ground-based observations of haloes and thick discs around edge-on galaxies, haloes around face-on disc galaxies, host galaxies around blue compact galaxies (BCGs), and haloes around elliptical galaxies. Surfacebrightness structures of all considered types of galaxies are modelled and analysed to compare scattered-light haloes and thick discs with measurements. I simulate the influence of scattered light and accurate sky subtraction on simplified Sérsic-type and face-on disc galaxy models. All galaxy models are convolved with both lower-limit and brighter point spread functions (PSFs); for a few galaxies it was possible to use dedicated PSFs. The results show bright scattered-light haloes and high amounts of red excess at large radii and faint surface brightnesses for nearly all types of galaxies; exceptions are the largest elliptical-type galaxies where the influence of scattered light is smaller. Studies have underestimated the role of scattered light to explain their surface-brightness profiles. My analysis shows surface-brightness profiles that include scattered light that are very similar to and overlap measurements at all radii. The derivation of physical properties of haloes, thick discs, and BCG hosts from diffuse data is misleading since accurate and radially extended PSFs are non-existent. Significantly improved analyses that include new measurements of PSFs are required to study diffuse faint structures further.

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Section: About Analyses Of Galaxy Structures That Are Fitted With Sérmentioning

confidence: 95%

Section: Choosing Representative Psfsmentioning

confidence: 99%

The influence of diffuse scattered light

Sandín

2015

A&A

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“…Notably, J08 comes to the same conclusion, based on models that are convolved with less extended PSFs. It seems that the CCD-specific red-halo effect (Sirianni et al 1998) plays a strong role to enhance the red excess in the i band.…”

Section: Discussionmentioning

confidence: 99%

“…The two V-band PSFs differ by up to 1 mag arcsec −2 , whilst the two i-band PSFs show a smaller difference. In general, PSFs show weak variations with wavelength, except measurements in the i-band that in some parts are affected by the CCDspecific red halo effect (Sirianni et al 1998). PSF K71 , PSF K73 , PSF P73 , and PSF CV (as well as PSF S74 , see Sect.…”

Section: An Overview Of Measured Radially Extended Psfsmentioning

confidence: 99%

The influence of diffuse scattered light

Sandín

2014

A&A

145

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All telescopes and instruments are to some degree affected by scattered light. It is possible to estimate the amount of such scattered light, and even correct for it, with a radially extended point spread function (PSF). The outer parts of the PSF have only rarely been determined, since they are faint and therefore difficult to measure. A mostly complete overview of existing properties and measurements of radially extended PSFs is presented, to both show their similarities and to indicate how bright extended objects can be used to measure the faintest regions. The importance of the far wings of the PSF and their possible temporal variations are demonstrated in three edge-on galaxy models. The same study is applied to the first edge-on galaxy where earlier observations reveal a halo, NGC 5907. All PSFs were collected in two diagrams, after they were offset or normalized, when that was possible. Surfacebrightness structures of edge-on galaxies were modelled and analysed to study scattered-light haloes that result when there is an exponential disc. The models were convolved with both a lower-limit PSF and a more average PSF. The PSF of the observed data could be used in the case of NGC 5907. The comparison of the PSFs demonstrates a lower-limit r −2 power-law decline at larger radii. The analysis of the galaxy models shows that the outer parts of the PSF also are important to correctly model and analyse observations and, in particular, fainter regions. The reassessed analysis of the earlier measurements of NGC 5907 reveals an explanation for the faint halo in scattered light, within the quoted level of accuracy.

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“…Many thinned CCD are prone to an instrumental source of extended PSF wings known as the "red-halo", first described from laboratory experiments by Sirianni et al (1998). It is due to multiple scattering in the CCD header, and could be much reduced by an appropriate modification.…”

Section: The "Red Halo" In the I Bandmentioning

confidence: 99%

Structure, colours, and populations of NGC 3115

Michard¹

2006

A&A

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Visible and near IR colour distributions in NGC 3115 have been studied from a set of frames of the Las Campanas Observatory and the 2MASS Atlas, plus other material from CFHT and OHP. The extended outer wings of the PSF were measured and their effect on such features as axis-ratio and colours carefully checked. In our data, the red-halo CCD phenomenon is the unique cause of a bluer major-axis in V − I. Morphological indices suggest that the disk of NGC 3115 was once a complete little spiral, before being "swallowed" by a much bigger object. All colour distributions show the major-axis slightly redder than the minor-axis regions, at least not far from centre, in the radial range where the disk stands out. This is interpreted in the framework of a bulge+disk model as a metallicity effect, the disk having locally a larger [Fe/H] by some 0.16 ± 0.04.

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<title>Long-wavelength scattered-light halos in ASC CCDs</title>

Cited by 24 publications

References 3 publications

The influence of diffuse scattered light

The influence of diffuse scattered light

The influence of diffuse scattered light

Structure, colours, and populations of NGC 3115

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