Spectral analysis of the Stromlo--APM Survey -- II. Galaxy luminosity function and clustering by spectral type

Loveday, Jon; Tresse, L.; Maddox, Steve

doi:10.1046/j.1365-8711.1999.02820.x

Cited by 45 publications

(59 citation statements)

References 32 publications

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“…The presence of still undetected objects of low optical and H i luminosity appears also likely, keeping in mind that the LF steepens towards the low-luminosity end for SFDGs (Loveday et al 1999), and in view of e.g. the high space density and the masses of local Lyα absorbers (Shull et al 1996).…”

Section: Introductionmentioning

confidence: 96%

“…ELGs were found to smoothly follow the structures delineated by luminous galaxies, although they are more fuzzily distributed (Rosenberg et al 1994), generally populating lower-density environments (Salzer 1989; K. Noeske et al: Faint companions in the close environment of star-forming dwarf galaxies 807 Telles & Terlevich 1995, hereafter TT95), and are less strongly clustered than less active luminous galaxies (Loveday et al 1999;Telles & Maddox 1999;Lee et al 2000). As for SFDGs, they were found to be concentrated towards void boundaries (Lindner et al 1996, hereafter L96), with a fraction (≈20%) of them inside voids (Pustilnik et al 1995), arranged in loose groups which do not contain any bright galaxies (L96).…”

Section: Introductionmentioning

confidence: 99%

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On faint companions in the close environment of star-forming dwarf galaxies

Noeske

Iglésias-Páramo

Vı́lchez

et al. 2001

A&A

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Abstract.We have searched for companion galaxies in the close environment of 98 star-forming dwarf galaxies (SFDGs) from field and low density environments, using the NASA Extragalactic Database. Most of the companions are dwarf galaxies which due to observational selection effects were previously disregarded in environmental studies of SFDGs. A subsample at low redshift, cz < 2000 km s −1 , was chosen to partially eliminate the observational bias against distant dwarf companions. We find companion candidates for approximately 30% of the objects within a projected linear separation sp < 100 kpc and a redshift difference ∆cz < 500 km s −1 . The limited completeness of the available data sets, together with the non-negligible frequency of H i clouds in the vicinity of SFDGs indicated by recent radio surveys, suggest that a considerably larger fraction of these galaxies may be accompanied by low-mass systems. This casts doubt on the hypothesis that the majority of them can be considered truly isolated. The velocity differences between companion candidates and sample SFDGs amount typically to < ∼ 250 km s −1 , and show a rising distribution towards lower ∆cz. This is similarly found for dwarf satellites of spiral galaxies, suggesting a physical association between the companion candidates and the sample SFDGs. SFDGs with a close companion do not show significant differences in their Hβ equivalent widths and B −V colours as compared to isolated ones. However, the available data do not allow us to rule out that interactions with close dwarf companions can influence the star formation activity in SFDGs.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

On faint companions in the close environment of star-forming dwarf galaxies

Noeske

Iglésias-Páramo

Vı́lchez

et al. 2001

A&A

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“…The slope of the correlation function, c, becomes steeper with increasingly red color. Both of these e †ects are known at lower redshift as morphological type or emission/absorption line galaxy correlations, although the large range of correlation amplitudes we Ðnd is not so readily apparent at low redshift (Davis & Geller 1976 ;Saunders, Rowan-Robinson, & Lawrence 1992 ;Fisher et al 1994 ;Guzzo et al 1997 ;Willmer, da Costa, & Pellegrini 1998 ;Loveday, Tresse, & Maddox 1999). The most relevant measure of correlation amplitude in a situation where the c vary systematically is to show the correlation length normalized to a Ðxed c, here chosen to be c \ 1.8.…”

Section: Introductionmentioning

confidence: 96%

Environment and Galaxy Evolution at Intermediate Redshift in the CNOC2 Survey

Carlberg

Yee

Morris

et al. 2001

ApJ

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The systematic variation of galaxy colors and types with clustering environment could either be the result of local conditions at formation or subsequent environmental e †ects as larger scale structures draw together galaxies whose stellar mass is largely in place. Below redshift 0.7 galaxy luminosities (k-corrected and evolution compensated) are relatively invariant, whereas galaxy star formation rates, as reÑected in their colors, are a "" transient ÏÏ property that have a wide range for a given luminosity. The relations between these galaxy properties and the clustering properties are key statistics for understanding the forces driving late-time galaxy evolution. At z D 0.4 the comoving galaxy correlation length, mear 0 , sured in the CNOC2 sample is strongly color dependent, rising from 2 h~1 Mpc to nearly 10 h~1 Mpc as the volume-limited subsamples range from blue to red. The luminosity dependence of at z D 0.4 is r 0 weak below in the R band, although there is an upturn at high luminosity, where its interpretation L * depends on separating it from the relation. In the B band there is a slow, smooth increase of r 0 -color r 0 with luminosity, at least partially related to the color dependence. Study of the evolution of galaxies within groups, which create much of the strongly nonlinear correlation signal, allows a physical investigation of the source of these relations. The dominant e †ect of the group environment on star formation is seen in the radial gradient of the mean galaxy colors, which on the average become redder than the Ðeld toward the group centers. The color di †erentiation begins around the dynamical radius of virialization of the groups. The redder-than-Ðeld trend applies to groups with a line-of-sight velocity dispersion, km s~1. There is an indication, somewhat statistically insecure, that the high-luminosity galp 1 [ 150 axies in groups with km s~1 become bluer toward the group center. Monte Carlo orbit intep 1 \ 125 grations initiated at the measured positions and velocities show that the rate of galaxy merging in the km s~1 groups is very low, whereas for km s~1 about 25% of the galaxies will merge p 1 [ 150 p 1 \ 150 in 0.5 Gyr. We conclude that the higher velocity dispersion groups largely act to suppress star formation relative to the less clustered Ðeld, leading to "" embalmed ÏÏ galaxies. On the other hand, the low velocity dispersion groups are prime sites of both strong merging and enhanced star formation that leads to the formation of some new massive galaxies at intermediate redshifts. The tidal Ðelds within the groups appear to be a strong candidate for the physical source of the reduction of star formation in group galaxies relative to Ðeld. Tides operate e †ectively at all velocity dispersions to remove gas-rich companions and low-density gas in galactic halos. We Ðnd a close resemblance of the color-dependent galaxy luminosity function evolution in the Ðeld and groups, suggesting that the clustering-dependent star formation reduction mechanism is important for the e...

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“…-When LFs are measured for 2 sub-samples separated by color (as in the Canada-France Redshift Survey, Lilly et al 1995; the CNOC1 survey, Lin et al 1997; and the Century Survey, Brown et al 2001), or separated by the equivalent width of characteristic emission lines (as in the ESO Slice Project, Zucca et al 1997; the Norris survey, Small et al 1997; and the Stromlo-APM survey, Loveday et al 1999; see also Lin et al 1996) they are insufficient for estimation of the intrinsic LFs as they not only fail to separate the various populations of giant and dwarf galaxies, but they also mix giant galaxies of different morphological type; this effect is illustrated using the ESO-Sculptor Survey (de Lapparent et al 2003b), for which PCA spectral types, colors and equivalent width of [OII] emission are available. -Although the COMBO-17 LFs in the B band (Wolf et al 2003) are consistent with those from the comparable CADIS (Fried et al 2001), and with those from the CNOC2 (Lin et al 1999) and ESO-Sculptor (de Lapparent et al 2003b) surveys, the COMBO-17 LFs converted into the U and R c bands shows significant differences with the CNOC2 and ESO-Sculptor for the intermediate spectral types corresponding to Spiral galaxies.…”

Section: Conclusion and Prospectsmentioning

confidence: 99%

“…At redshifts larger than ∼0.1, visual morphological classification becomes highly uncertain and is replaced by spectral classification (Heyl et al 1997;Bromley et al 1998;Lin et al 1999;Folkes et al 1999;Fried et al 2001;Madgwick et al 2002;Wolf et al 2003;de Lapparent et al 2003b). Other redshifts surveys for which a spectral classification is not available use either colors (Lilly et al 1995;Lin et al 1997;Metcalfe et al 1998;Brown et al 2001) or the strength of the emission lines (Lin et al 1996;Small et al 1997;Zucca et al 1997;Loveday et al 1999) for estimating the LFs of the different galaxy types. The widely varying criteria used for galaxy classification in systematic redshift surveys however complicate the interpretation and inter-comparison of the derived LFs.…”

Section: Introductionmentioning

confidence: 99%

Critical analysis of the luminosity functions per galaxy type measured from redshift surveys

Lapparent

2003

A&A

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Abstract. I perform a quantitative comparison of the shape of the optical luminosity functions as a function of galaxy class and filter, which have been obtained from redshift surveys with an effective depth ranging from z 0.01 to z 0.6. This analysis is based on the M * and α Schechter parameters which are systematically measured for all galaxy redshift surveys. I provide complete tables of all the existing measurements, which I have converted into the UBVR c I c Johnson-Cousins system wherever necessary.By using as reference the intrinsic luminosity functions per morphological type, I establish that the variations in the luminosity functions from survey to survey and among the galaxy classes are closely related to the criteria for galaxy classification used in the surveys, as these determine the amount of mixing of the known morphological types within a given class. When using a spectral classification, the effect can be acute in the case of inaccurate spectrophotometric calibrations: the luminosity functions are then biased by type contamination and display a smooth variation from type to type which might be poorly related to the intrinsic luminosity functions per morphological type. In the case of surveys using multi-fiber spectroscopy, galaxy classification based on rest-frame colors might provide better estimates of the intrinsic luminosity functions.It is noticeable that all the existing redshift surveys fail to measure the Gaussian luminosity function for Spiral galaxies, presumably due to contamination by dwarf galaxies. Most existing redshift surveys based on visual morphological classification also appear to have their Elliptical/Lenticular luminosity functions contaminated by dwarf galaxies. In contrast, the analyses using a reliable spectral classification based on multi-slit spectroscopy or medium-filter spectrophotometry, and combined with accurate CCD photometry succeed in measuring the Gaussian luminosity function for E/S0 galaxies. The present analysis therefore calls for a more coherent approach in separating the relevant giant and dwarf galaxy types, a necessary step towards measuring reliable intrinsic luminosity functions.

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Spectral analysis of the Stromlo--APM Survey -- II. Galaxy luminosity function and clustering by spectral type

Cited by 45 publications

References 32 publications

On faint companions in the close environment of star-forming dwarf galaxies

On faint companions in the close environment of star-forming dwarf galaxies

Environment and Galaxy Evolution at Intermediate Redshift in the CNOC2 Survey

Critical analysis of the luminosity functions per galaxy type measured from redshift surveys

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