The Sloan Digital Sky Survey

a r X i v :a s t r o -p h /0207189v 1 9 J u l 2002The Sloan Digital Sky Survey

Jon Loveday,for the SDSS collaboration

Astronomy Centre,University of Sussex,Falmer,Brighton,BN19QJ,England

February 1,2008Abstract The Sloan Digital Sky Survey (SDSS)is making a multi-colour,three dimensional map of the nearby Universe.The survey is in two parts.The ?rst part is imaging one quarter of the sky in ?ve colours from the near ultraviolet to the near infrared.In this imaging survey we expect to detect around 50million galaxies to a magnitude limit g ～23.The second part of the survey,taking place concurrently with the imaging,is obtaining spectra for up to 1million galaxies and 100,000quasars.From these spectra we obtain redshifts and hence distances,in order to map out the three-dimensional distribution of galaxies and quasars in the Universe.These observations will be used to constrain models of cosmology and of galaxy formation and evolution.This article describes the goals and methods used by the SDSS,the current status of the survey,and highlights some exciting discoveries made from data obtained in the ?rst two years of survey operations.1Introduction What is the Universe made of?How did the Universe begin?How will it end?These are some of the fundamental questions which can be addressed by studying the large scale

distribution of galaxies in the Universe.It is widely believed that the galaxies we see today formed at the sites of tiny (～1part in 105)density ?uctuations in the early Universe.The form of these density ?uctuations (which,if Gaussian in nature,may be fully described by their power spectrum)are predicted by cosmological models,and depend on such parameters as the mean matter density ?m ,the fraction of baryonic matter ?b /?m and any contribution to the cosmological density from vacuum energy,also known as the cosmological constant ?Λ.On large scales,the clustering of galaxies can be predicted from the primordial density ?uctuations using linear perturbation theory.By measuring this large-scale clustering,we can thus obtain important constraints on cosmological models.By studying the intrinsic properties of the galaxies themselves,such as luminosity,colour and morphology,we can test theories for how galaxies are born and evolve.

In order to measure the clustering of galaxies reliably,it is important to use a systematic and well-de?ned catalogue.Systematic surveys date back to that of Messier,published in three parts in the 1770s and 1780s,although it was not realized at the time that some of the nebulae catalogued by Messier were other galaxies outside our own Milky Way.It was only in 1923,by a careful measurement of the distance to the Andromeda Nebula (M31in Messier’s catalogue),that Edwin

Hubble proved de?nitively that M31was a large galaxy separate from our own.Hubble later discovered the expansion of the Universe,and found that the recession velocity of a galaxy is in direct proportion to its distance from us,the Hubble law.Since then,a number of galaxy surveys have been published,starting with that of Shapley and Ames in1932[33],and including more recently the APM Galaxy Survey[24],which contains positions and magnitudes for about three million galaxies.Most of these surveys are based on photographic plates,and there is concern that such surveys could be missing a substantial fraction of low surface-brightness galaxies,eg.[8].There is also apprehension that uncertainties in the photometric calibration of these surveys could lead to spurious measurement of galaxy clustering on large scales[12,23].

Smaller surveys have been made using charge coupled device(CCD)detectors.These solid state devices,unlike photographic plates,have a linear response to light and～50times higher quantum e?ciency,but the limited size of these detectors has before now precluded the construction of wide-area galaxy surveys.

In order to map out the three-dimensional distribution of galaxies,as opposed to just their two-dimensional projection on the celestial sphere,one needs the distance to each galaxy.This may be obtained by measuring the spectrum of light emitted by a galaxy.The Doppler shift in features towards the red end of the spectrum(the redshift)may be used to infer a galaxy’s recession velocity and hence its distance from the Hubble relation.Until recently,galaxy spectra were painstakingly measured one-by-one,and it is only in the last few years that optical?bre multiplexing has been used to measure redshifts for many thousands of galaxies.

The largest redshift survey to date is the nearly-completed Two Degree Field(2dF)Galaxy Redshift Survey carried out on the Anglo-Australian Telescope[6].While containing redshifts for more than 200,000galaxies,the2dF survey is based on the photographic APM Galaxy Survey,with the potential problems mentioned above.

The Sloan Digital Sky Survey(SDSS)collaboration was therefore formed in1988with the aim of constructing a de?nitive map of the local universe,incorporating CCD imaging in several passbands over a large area of sky,and measurement of redshifts for around one million galaxies.In order to complete such an ambitious project over a reasonable timescale,it was decided to build a dedicated 2.5-metre telescope equipped with a large CCD array imaging camera and multi-?bre spectrographs. The survey itself began in April2000,and observations are scheduled to?nish in June2005.In this article I review some important aspects of the survey,including an overview of survey operations (§2),a description of the preliminary public data release(§3),and a selection of some early science results(§4).

2Survey Overview

2.1Goals

The basic goal of the survey is to make a de?nitive map of the local Universe,which can then be used to constrain cosmological models and models for the formation and evolution of galaxies.This map will consist of5-colour imaging to a g-band limiting magnitude m≈23over a contiguous area ofπsteradians(10,000square degrees)in the northern sky and three,non-contiguous stripes with total area740square degrees in the southern sky.(Magnitudes measure?ux on a logarithmic scale,

where smaller magnitudes correspond to larger?ux.The magnitude di?erence between two stars of?ux f1and f2is de?ned to be m1?m2=?2.5lg(f1/f2).The brightest stars have magnitude m≈1,the faintest stars visible to the naked eye have m≈6,ie.100times fainter.A magnitude m≈23thus corresponds to an observed?ux which is roughly six million times fainter than that of the dimmest naked-eye stars.)From this imaging data we can map out the two-dimensional distribution of galaxies and quasars as projected on the celestial sphere.Distances to a subset of these objects will be determined by observing spectra of roughly one million galaxies and100,000 quasars.The spectrum of a galaxy or quasar enables one to measure its recession velocity v from the Doppler redshift of spectral features.Distances d may then be estimated from the Hubble law:v=H0d,where H0≈70km/s/Mpc is the Hubble parameter.In this way,we can map out the three-dimensional distribution of objects in space.(Astronomers often measure extragalactic distances in units of Mpc where1Mpc=106parsecs,and1parsec≈3.09×1016m.Uncertainty in the value of H0leads to a corresponding uncertainty in distances derived from the Hubble relation. To re?ect this,distances are often written in units of h?1Mpc,where H0=100h km/s/Mpc.)

2.2Hardware and operations

The SDSS consists of two concurrent surveys,one photometric and one spectroscopic.To complete a digital survey over a large fraction of the sky within a reasonable timescale,it is necessary to conduct wide-?eld imaging and multi-object spectroscopy.To meet this need,a wide-?eld telescope,imaging camera and multi-?bre spectrographs were designed and built speci?cally for this purpose,which I describe very brie?y below.

The survey hardware comprises the2.5-metre survey telescope,a0.5-metre photometric telescope (called the monitor telescope in its previous incarnation),a state-of-the-art imaging camera[14] that observes near-simultaneously in?ve passbands covering the near-ultraviolet to near-infrared, and a pair of dual beam spectrographs,each capable of observing320?bre-fed spectra.The site is also equipped with a10-micron all-sky camera[17],which provides rapid warning of any cloud cover.The data are reduced by a series of automated pipelines and the resulting data products stored in an object-oriented database.

The main survey telescope is of modi?ed Ritchey-Chr′e tien design[39],with a primary aperture of2.5m and a focal ratio of f/5to produce a?at?eld of3?with a plate scale of16.51arc-sec/mm.It is situated at Apache Point Observatory,near Sunspot,New Mexico,at a height of2,800m.The telescope is housed in an enclosure which rolls o?for observing,and is encased in a co-rotating ba?e which protects it from wind disturbances and stray light.This unique de-sign allows the telescope to remain free of dome-induced seeing.Photographs of the site and telescope can be found at https://www.wendangku.net/doc/bf12487178.html,/.A technical overview of the survey has been given by York et al.[40]and further details are available online in the SDSS Project Book at https://www.wendangku.net/doc/bf12487178.html,/PBOOK/welcome.htm.

2.3Imaging Survey

The photometric imaging survey will produce a database of roughly108galaxies and108stellar objects,with accurate(≤0.10arcsec)astrometry,5-colour photometry,and object classi?cation parameters.This database will become a public archive.

Figure1:Front view of the imaging camera assembly.The ugriz imaging CCDs are colour-coded blue,green,red,black and orange respectively.The astrometric CCDs are shown as narrow red rectangles.The arrows indicate the direction of motion of astronomical sources across the imaging array,which subtends2.3?on the sky.

The imaging camera[14](Figure1)consists of54CCDs in eight dewars and spans2.3?on the sky. Thirty of these CCDs are the main imaging/photometric devices,each a SITe(Scienti?c Imaging Technologies,formerly Tektronix)device with2048×204824μpixels.They are arranged in six dewars aligned with the scan direction and holding5CCDs each,one CCD for each?lter bandpass. The camera operates in TDI(Time Delay and Integrate),or scanning,mode for which the telescope is driven at a rate synchronous with the charge transfer rate of the CCDs.Objects on the sky drift down the CCD array so that nearly simultaneous5-colour photometry is obtained.The e?ective integration time,i.e.the time any part of the sky spends on each detector,is55seconds at the chosen(sidereal)scanning rate,which results in a limiting magnitude of g～23.

The SDSS photometric system u′g′r′i′z′[13](Figure2)has been speci?cally designed for this survey and covers the near-UV to near-IR range(～3000–10,000?A)in?ve essentially non-overlapping passbands.The u?lter response peaks in the near ultra-violet at3500?A,g is a blue-green band centred at4800?A,r is a red band centred at6250?A,i is a far-red?lter centred at7700?A and z is a near-infrared passband centred at9100?A.The standard stars that de?ne this system have been presented by Smith et al.[34].The photometric data are not yet?nally calibrated,so the current magnitudes are indicated with asterisks,u?g?r?i?z?,to denote their preliminary nature.The SDSS ?lters themselves are referred to simply as ugriz,without primes or asterisks.

In order to provide photometric calibration while the imaging camera is scanning,a second,dedi-cated Photometric Telescope operates concurrently,observing photometric standard stars and cre-ating photometrically calibrated“secondary patches”which lie within the main telescope’s scan. These calibration patches are then used to transfer the primary photometric calibration to objects detected with the2.5m telescope and imaging camera.The photometric quality of the data is monitored by a software“robot”that automatically rejects data observed during cloudy periods [16].

The other24CCDs in two additional dewars are also SITe chips of width204824μpixels,but they have only400rows in the scanning direction.These dewars are oriented perpendicular to the photometric dewars,with one at the top and one at the bottom of the imaging array.Two of these CCDs(one in each dewar)are used to determine changes in focus.The remaining22CCDs reach brighter magnitudes before saturating and are used to tie our observations to an astrometric reference frame de?ned by bright stars which saturate our imaging detectors[28].

The location of the survey imaging area is shown in Figure3.The northern survey area is centred near the North Galactic Pole and it lies within a nearly elliptical shape130?E-W by110?N-S chosen to minimize Galactic foreground extinction.All scans are conducted along great circles in order to minimize the transit time di?erences across the camera array.There are45great circles (“stripes”)in the northern survey region separated by2.5?.We observe three non-contiguous stripes in the Southern Galactic Hemisphere,at declinations of0,+15?and?10?,during parts of the autumn season when the northern sky is unobservable.Each stripe is scanned twice,with an o?set perpendicular to the scan direction in order to interlace the photometric columns.A completed stripe slightly exceeds2.5?in width and thus there is a small amount of overlap to allow for telescope mis-tracking and to provide multiple observations of some fraction of the sky for quality assurance purposes.The total stripe length for the45northern stripes will require a minimum of 650hours of pristine photometric and seeing conditions to scan at a sidereal rate.Based upon our current experience of observing conditions at APO,it seems likely that we will only complete about 75%of this imaging after5years of survey operations.

Figure2:SDSS photometric system response as a function of wavelength in Angstroms.The upper curve is without atmospheric extinction,the lower curve includes the e?ects of atmospheric extinction when observing at a typical altitude of56?.

Figure3:The location of the survey imaging stripes plotted in a polar projection for the North(left) and South(right)Galactic hemispheres.The grey scale indicates the amount of reddening due to dust in our own Galaxy[31],where white corresponds to no reddening and black to one magnitude of reddening in g?r colour.The circles are lines of constant Galactic latitude(|b|=30?,60?),and Galactic longitude is marked around the edge of each hemisphere.

2.4Spectroscopic Survey

The goals of the spectroscopic survey are to observe spectra for106galaxies,105quasars and105 stars.In order to obtain the spectra of over106objects in a survey covering104square degrees, we must obtain spectra of about100objects per square degree.Although some overlap of?elds is inevitable,we would like to keep this overlap to a minimum for reasons of e?ciency and cost. Hence,we need to obtain several hundred spectra per3?diameter spectroscopic?eld.

To accommodate this requirement,two identical multi-?bre spectrographs have been built which are each fed by320?bres.The spectrographs cover the wavelength range3900–9100?A at a resolution ofλ/?λ～1800,or167km s?1.Each spectrograph has two cameras,one optimized for the red and the other for the blue.Each camera has as its detector a2048×2048CCD with24μpixels. The180μ?bres,which each subtend3′′on the sky,are located in the focal plane by plugging them by hand into aluminium plates which are precisely drilled for each?eld based upon the astrometric solution obtained from the imaging data.To avoid mechanical interference,individual?bres can be placed no closer than55′′to one another.The plates and?bres are held in the focal plane, and coupled with the spectrographs,by one of9identical rigid assemblies called cartridges.Since all of the cartridges can be pre-plugged during the day,5,760spectra can be obtained during a long night without re-plugging.A mapping procedure is invoked after plugging each cartridge that automatically tags each?bre to the appropriate object on the sky.

A surface density of100galaxies per square degree corresponds roughly to an r-band magnitude limit r≈18.To obtain redshifts for galaxies of this magnitude requires exposure times of about45 minutes,which we split into three,15minute exposures to aid in rejection of cosmic rays.Cosmic ray

events occur at essentially random locations on our detectors,and so are very unlikely to appear at the same place in all three exposures.Each?eld takes about one hour,including calibration (?at?eld and comparison lamp)exposures and allowing for telescope pointing and the exchange of ?bre cartridges.Spectroscopic observations are carried out whenever observing conditions are not adequate for imaging,ie.when seeing exceeds1.5arcsec or when skies are non-photometric.

2.5Data Processing

All of the raw data from the photometric CCDs are archived.The frames are?rst read to disk, then written to DLT tape.Over16Gb per hour are generated from the photometric chips.When observing in spectroscopic mode,the amount of data generated seems trivial in comparison(about 6exposures per hour for each of two cameras for each of two spectrographs,or248Mb frames per hour).

All data tapes are shipped by overnight express courier to Fermi National Accelerator Laboratory, near Chicago,where the data reduction pipelines are run.The goal is to turn the imaging data around within a few days,so that one dark run’s worth of imaging data will be processed before the next dark run begins,allowing objects to be targeted for spectroscopy.The data?ow serially through several pipelines to identify,measure and extract astronomical images and to apply photometric and astrometric calibrations.Once a signi?cant area of sky has been imaged,a target selection procedure is then run in order to select objects for followup spectroscopy.Next,an adaptive tiling algorithm assigns targets to spectroscopic plates and chooses plate centres in order to maximize observing e?ciency[4].Since galaxies are clustered on the sky,the target density varies from place to place.In regions of high target density,the adaptive tiling algorithm allows the plates to move slightly closer together so that all targets can be observed.The plates are then manufactured and shipped to the site.

Spectroscopic reduction is also automated.We are able to obtain correct redshifts for99%of targeted objects,without human intervention.The pipelines are integrated into a specially-written environment known as Dervish,and the reduced data are stored in an object-oriented database. 2.6Spectroscopic Samples

There are several distinct spectroscopic samples observed by the survey.In a survey of this magni-tude,it is important that the selection criteria for each sample remain?xed throughout the duration of the survey.Therefore,we spent a whole year obtaining test data with the survey instruments and re?ning the spectroscopic selection criteria in light of our test data.Now that the survey proper is underway,these criteria have been“frozen in”for the duration of the survey.

The main galaxy sample[36]consists of～900,000galaxies selected by r band magnitude, r?<17.77.This magnitude limit was chosen as test year data demonstrated that it corresponds closely to the desired target density of90objects per square degree.Since galaxies are fuzzy, extended sources,there is no easy way to measure their total magnitude.Most previous surveys have measured the light within an isophote of constant surface brightness,but these isophotal magnitudes will systematically underestimate the?ux of galaxies of low intrinsic surface brightness and at high redshift z,since observed surface brightness scales as(1+z)4.Simulations have shown

that the Petrosian magnitude[27],which is based on an aperture de?ned by the ratio of light within an annulus to total light inside that radius,provides probably the least biased and most stable estimate of total magnitude.We therefore select galaxies according to their Petrosian magnitude. We also apply a surface-brightness limit,μr?<24.5mag arcsec?2,so that we do not waste?bres on galaxies of too low surface brightness to give a reasonable spectrum.This surface brightness cut eliminates just0.1%of galaxies that would otherwise be selected for observation.Galaxies in this sample have a median redshift z ≈0.104.

We will observe an additional～100,000luminous red galaxies[10].Given photometry in the ?ve survey bands,redshifts can be estimated for the reddest galaxies to?z≈0.02or better,and so one can also predict their intrinsic luminosities quite accurately.The luminous red galaxies, many of which will be so-called central dominant(cD)galaxies in cluster cores,provide a valuable supplement to the main galaxy sample since1)they have distinctive spectral features,allowing a redshift to be measured for objects to a?ux limit around1.5magnitudes fainter than the main sample,and2)they form a volume-limited sample,ie.a sample of uniform density,out to redshift z=0.38.This sample will thus be extremely powerful for studying clustering on the largest scales and for investigating galaxy evolution.

Quasar candidates[29]are selected from cuts in multi-colour space and by identifying sources from the FIRST radio catalogue[2],with the aim of observing～100,000quasars.This sample will be orders of magnitude larger than any existing quasar catalogue,and will be invaluable for quasar luminosity function,evolution and clustering studies as well as providing sources for followup absorption-line observations.

In addition to the above three classes of spectroscopic sources,which are designed to provide statis-tically complete samples,we are also obtaining spectra for many thousands of stars and for various serendipitous objects.The latter class includes objects of unusual colour or morphology which do not?t into the earlier classes,plus unusual objects found by other surveys and in other wavebands.

2.7Survey Status

First light with the imaging camera was obtained on9May1998and the?rst extra-galactic spectra were obtained in June1999.The survey o?cially began on1April2000,and observing is scheduled to end on30June2005.At the time of writing(June2002),we have imaged4278square degrees (40%of the total survey area)and obtained spectra for621plug-plates,yielding spectra for264,995 galaxies,37,612quasars and50,023stars,including some repeated observations.The spectrographs are performing extremely e?ciently,with an overall throughput,including telescope optics but excluding the atmosphere,of20%in the blue(3900–6000?A)and25%in the red(6000–9100?A). Automated spectral reduction pipelines classify these spectra and measure redshifts.Conservatively, we inspect the spectra of roughly8%of sources,whenever there is any doubt about the reliability of the automated redshift measurement.In seven-eighths of these cases,the automated redshift measurement is in fact con?rmed to be correct.The remaining eighth of these spectra(1%overall) have their redshifts manually corrected.Based on manual inspection of all≈23,000spectra from 39plugplates,this procedure correctly measures redshifts for99.7%of galaxies,98.0%of quasars and99.6%of stars.

3The Early Data Release

The?rst public release of SDSS data(hereafter EDR)took place on5June2001,and consists of images covering460square degrees of sky,photometric parameters for10million objects and spectra for54,000objects.The main access point to the data is through the website https://www.wendangku.net/doc/bf12487178.html,/ and the EDR is described in[35].

There are presently three ways to access the data,the choice of which depends on the nature of the data required and the experience of the user.

The SkyServer(https://www.wendangku.net/doc/bf12487178.html,)provides a graphical user interface to images of the sky and also enables one to download spectra of speci?ed objects.It was primarily intended as an interface for the general public and for educational purposes,but new features are being added, making it also useful for professional astronomers.Public interest in the SDSS is illustrated by the fact that this web site has been receiving around half a million hits per month.

The MAST interface(https://www.wendangku.net/doc/bf12487178.html,/sdss/)allows simple web-based searches around speci?ed objects or positions on the sky.It is a useful way of retrieving SDSS observations for mod-erate numbers of objects in a small region of the sky.

For accessing SDSS data on large numbers of objects,and over larger areas,the SDSS query tool sdssQT is recommended.This tool allows one to query the EDR database on any measured parameters and to specify which parameters,such as position and magnitude,are to be returned. Documentation on the query tool is available from https://www.wendangku.net/doc/bf12487178.html,/sdss/software/. The distribution of equatorial galaxies in the EDR is shown in right ascension(RA)versus redshift wedge plots in Figure4.The main galaxy sample is?ux-limited(r?<17.6)and has a median redshiftˉz≈0.11.The clustering of galaxies is clearly visible in this plot:the galaxies appear to lie within?lamentary structures enclosing regions of substantially lower density.The drop in galaxy density with redshift(distance from the centre of the plot)is entirely due to the fact that this sample is limited by apparent?ux:only the most luminous galaxies,which are rare,can be seen beyond a redshift z 0.15.

By contrast,the luminous red galaxy(LRG)sample is designed to be volume-limited,ie.to be of uniform density,out to redshift z=0.38.This sample also includes additional galaxies to z～0.5, although these high redshift galaxies do not form a complete subsample.At z<0.15,the simple linear colour cut used allows less luminous galaxies to enter the sample,hence the increase in galaxy density at these low redshifts.

The EDR includes some engineering data of sub-survey standard,and will be superseded by the ?rst o?cial data release,DR1,in January2003.This release will include spectra of more than 200,000objects over2800square degrees of sky.Subsequent data releases will follow at roughly yearly intervals.

Figure 4:Distribution of EDR galaxies in right ascension (RA)and redshift around the equator (declination |δ|<1.25deg).The left plot shows 24,915galaxies from the main ?ux-limited galaxy sample within a redshift z =0.2.The right plot shows 8025galaxies from the luminous red galaxy sample to z =0.5.

4Early Science Results

Although the primary science driver behind the Sloan Digital Sky Survey is characterization of the large scale structure of the Universe,the survey has already had a signi?cant impact on several branches of astrophysics,from the investigation of asteroids in our own Solar System to the discovery of the most distant known objects in the Universe.Here I very brie?y highlight some interesting results which have come out of the commissioning phase of the survey.For further details,please see the original articles as referenced.

4.1Asteroids

Asteroids are easily detected in SDSS imaging data since they are fast-moving and very nearby (within the Solar System),leading to a signi?cant motion relative to the background stars during the 55s integration time.They thus appear on SDSS images as trails,the length and orientation of which enable the asteroid’s orbit to be determined.Around 13,000asteroids have been detected in 500deg 2of SDSS commissioning data [18].These observations have enabled an accurate determination of the size distribution of asteroids to r ?<21.5over the range 0.4–40km.The total number of predicted asteroids with r ?<21.5is about a factor of ten smaller than that predicted by an extrapolation from previous observations of brighter asteroids (r ? 18),and the number of “killer”asteroids with diameter D >1km is a factor of about three smaller than previously thought,with a new estimate of roughly one impact per 500,000years.By completion,we estimate that the SDSS will have observed roughly 100,000asteroids in ?ve colours,enabling their approximate chemical

composition to be determined.There is already clear evidence for chemical segregation in the belt of asteroids between Mars and Jupiter.Asteroids in the inner part of the belt are composed mostly of rocky silicates,whereas the outer belt asteroids are primarily carbonaceous.These observations have important implications for the formation history of the Solar System.

4.2Brown Dwarfs and Methane Dwarfs

Moving slightly further a?eld than the Solar System,the SDSS has also been very successful at ?nding brown dwarfs in the vicinity of the Sun.Brown dwarfs are sub-stellar objects which are too small to sustain thermonuclear reactions in their cores,and are thus not true stars,but are larger than planets(they are thought to be10–70times the mass of Jupiter).They are thus cool, below2,500K,and hence very red,enabling them to be easily distinguished from true stars by their colours in the SDSS?lters.To date[15],SDSS has discovered around?fty new brown dwarfs, including four T-dwarfs,also known as methane dwarfs.The methane dwarfs are so cool,below 1,300K,that their spectra are dominated by the presence of molecules such as water vapour and methane.While a methane dwarf,Gliese229B,had already been discovered in orbit around a brighter star,the SDSS was the?rst survey to discover free-?oating methane https://www.wendangku.net/doc/bf12487178.html,ing the discovery technique pioneered by SDSS,the Two Micron All Sky Survey(2MASS)has since found more than a dozen methane dwarfs[5].Although very low in mass,these elusive objects may be very common,and thus may provide a signi?cant fraction of the“dark matter”that is known to exist in the Milky Way.To understand their contribution to the total mass of the Milky Way requires determining both their abundance and their mass.The SDSS will be important in addressing both these questions,due to its capability of obtaining precision?ve-colour photometry over a very large area of sky.

4.3Star Structures in the Galaxy

The SDSS has discovered an unexpectedly large number of blue stars within20degrees of the Galactic plane.It is thought that these stars could be part of a disrupted dwarf galaxy,or a disk-like distribution of stars that is pu?er than accepted models of the stellar disk of the Galaxy,and ?atter than the spherical distribution in the halo[26].These observations suggest that the model for our Galaxy needs to be reconsidered.One possible explanation is that these star structures came from tidal disruption of nearby dwarf galaxies such as Sagittarius,since the ages and metallicities of the stars are consistent with the stellar populations in Sagittarius.

4.4Galaxy luminosity function

The distance to a galaxy can be obtained from its spectroscopic redshift using Hubble’s law,which says that the recession velocity of a galaxy is linearly proportional to its distance.Knowing the distance to a galaxy,its intrinsic luminosity may be determined from its apparent magnitude using the inverse-square law.By calculating the maximum distance to which a galaxy of given luminosity may be seen,one can?nd the galaxy luminosity function,φ(L),the number density of galaxies as a function of intrinsic luminosity.It has long been known that the galaxy LF is well?t by the

Schechter function[30],

φ(L)dL=φ? L L? d L

Figure5:Left:(a)Expected1σuncertainty in the galaxy power spectrum P(k)we would measure from a volume-limited sample from the completed SDSS northern survey,along with predictions of P(k)from four variants of the low-density CDM model.Note that the models have been arbitrarily normalized to agree on small scales(k=0.4);in practice the COBE observations of CMB?uctu-ations?x the amplitude of P(k)on very large scales.Right:(b)Power spectrum expected from the luminous red galaxy sample(BRGs),assuming that these galaxies are four times as strongly clustered as the main sample galaxies.

4.5.1Angular clustering

A series of papers[7,9,32,37,38]have studied the angular clustering of galaxies in SDSS commis-sioning data.These papers are based on a single survey stripe(runs752/756observed in March 1999)measuring2.5×90degrees and containing some3million galaxies to r?=22.Star-galaxy separation is performed using a Bayesian likelihood and approximately30%of the area is masked out due to poor seeing[32].The angular correlation function,w(θ),which describes the excess probability over random of?nding two galaxies at angular separationθ,is consistent with that measured from the APM Galaxy Survey[22]when scaled to the same depth[7].

An important test of the star-galaxy separation and of the photometric calibration is to check that w(θ)scales as expected with apparent magnitude.(We expect w(θ)to shift to smaller angular scales and a lower amplitude as we look at more distant,and hence apparently fainter,galaxies. This scaling is quanti?ed by Limber’s equation[19].)Figure6shows that the scaling of w(θ)is well-described by Limber’s equation,particularly when a vacuum-dominated(?m=0.3,?Λ=0.7) cosmology is assumed.Further tests for possible sources of systematic errors in the SDSS data are described in detail in[32]and the angular clustering results are summarized in[7].

Λ-dominated cosmology.From[32].

4.5.2Spatial clustering

A preliminary estimate of the spatial clustering of galaxies has been made using redshift information

[41].This sample consists of29,300galaxies with r?<17.6and within±1.5magnitudes of the characteristic magnitude M?r(corresponding to the characteristic luminosity L?in the Schechter function?t to the luminosity function,see§4.4),distributed non-contiguously over690square degrees.

When using redshifts to infer distances,one relies on the Hubble relation,ie.that distance is proportional to recession velocity.In fact,galaxies have peculiar velocities relative to the Hubble expansion,leading to an error in estimated distances.It is important to take these distance errors, or redshift-space distortions,into account when measuring galaxy clustering.One way of doing this is to estimate galaxy clustering as a functionξ2(r p,π)of two components of the separation vector:the line of sight separationπ,which is a?ected by peculiar velocities,and the sky-projected separation r p,which is not.In the absence of redshift-space distortions,the contours ofξ2(r p,π) would be symmetric about the origin,but small-scale peculiar velocities cause an elongation of the contours along the line of sight directionπ,the so-called“?nger of God”e?ect.One can estimate a projected correlation function w p(r p)that is una?ected by redshift-space distortions by integrating ξ2(r p,π)along the line of sightπ,

w p(r p)=2 ∞0dπξ2(r p,π)=2 ∞0dyξ(

Figure 7:Projected correlation functions w p (r p )against projected separation r p for redshift survey galaxies subdivided by colour (left plot)and luminosity (right plot).Note that the slope of w p (r p )increases from blue to red colour,but remains approximately constant with luminosity.From [41].Table 1:Power-law parameters for the real-space correlation function ξ(r )=(r/r 0)?γ.Units for the correlation length r 0are h ?1Mpc.From [41].

Sample r 0γ

0200

400

600

800

u ′ Luminosity 02468M a s s

01234 g ′ Luminosity M a s s 0.512230246 0200

400

600

800

r ′ Luminosity 05101520M a s s 0246810 β 0.5 1.0 1.5 2.0i ′ Luminosity M a s s 024605101520250.00.5 1.0

1.5

2.0

β0

200

400

600

800

? (h M O ? /L O ?)z ′05101520Luminosity 0510152025M a s s Figure 8:Mass-luminosity relation in the ?ve SDSS bands estimated from weak lensing.The inset in each panel plots estimated mass within 260h ?1kpc (M 260)as a function of lens luminosity.The contours show 1,2and 3sigma con?-dence limits on the scale factor Υand the power-law index βin the relation M 260=Υ(L/1010L ⊙)β.Note that inferred mass has only very weak dependence on u -band luminosity,but in the redder survey bands griz ,the mass-luminosity relation appears to be linear.From [25].

Figure 7shows the clustering properties for two subsamples of the galaxy population selected by restframe u ?r colour at (u ??r ?)0=1.8,corresponding roughly to bulge (red)and disk (blue)dominated galaxies.The red galaxies exhibit a steeper power-law slope and longer correlation length than the blue galaxies,as indicated by the power-law ?t parameters in Table 1.Also shown in Figure 7are the correlation functions for three,volume-limited samples,with luminosities centered on M ??1.5,M ?and M ?+1.5(bright,medium and faint).The power-law slopes for these samples are all consistent with γ=1.8,although the correlation length r 0decreases as expected from bright to faint luminosities.

4.6Galaxy-mass correlation function

So far,I have summarized recent SDSS results concerning the distribution of luminous matter in the Universe.Direct constraints on the dark matter distribution may be obtained from gravita-tional lensing,in which the images of background sources are distorted by the gravitational ?eld of foreground masses.McKay et al.[25]have made weak lensing measurements of the surface mass density contrast around foreground galaxies of known redshift.Although the lensing signal is too weak to detect about any single lens,by stacking together around 31,000lens galaxies a clear lensing signal is detected.The galaxy-mass correlation function is well ?t by a power-law of the

form?Σ+=2.5(r/Mpc)?0.8hM⊙pc?2,where M⊙represents the mass of the Sun.The strength of correlation is found to increase with the following properties of the lensing galaxy:late→early-type morphology,local density and luminosity in all bands apart from u′.Figure8shows the relationship between inferred mass within a260h?1kpc radius and luminosity in each of the survey bands.

4.7High-redshift quasars

The SDSS has broken the z=6redshift barrier,with the discovery of a quasar at a redshift z=6.28, along with two new quasars at redshifts z=5.82and z=5.99[11].These objects were selected as i-dropouts:i??z?>2.2and z?<20.2.Contaminating L and T dwarfs were eliminated with followup near-IR photometry and con?rming spectra were obtained with the ARC3.5m telescope. The SDSS has now observed a well-de?ned sample of four luminous quasars at redshift z>5.8. The Eddington luminosities of these quasars are consistent with a central black hole of mass several times109M⊙,and with host dark matter halos of mass～1013M⊙.The existence of such mass concentrations at redshifts z≈6,when the Universe was less than1Gyr old,provides important constraints on models of formation of massive black holes.We expect to discover～27z>5.8 quasars and one z≈6.6quasar by the time the survey is complete.Such observations will set strong constraints on cosmological models for galaxy and quasar formation.

5Conclusions and Acknowledgments

The Sloan Digital Sky Survey is now fully operational and is producing high quality data at a prodigious rate.We have imaged4278deg2of sky in?ve colours and have obtained more than 350,000spectra.Much exciting science has already come out of just a small fraction of the?nal dataset and we look forward to many more exciting discoveries in the coming years.

Funding for the creation and distribution of the SDSS Archive has been provided by the Alfred P.Sloan Foundation,the Participating Institutions,the National Aeronautics and Space Adminis-tration,the National Science Foundation,the U.S.Department of Energy,the Japanese Monbuka-gakusho,and the Max Planck Society.The SDSS Web site is https://www.wendangku.net/doc/bf12487178.html,/.

The SDSS is managed by the Astrophysical Research Consortium(ARC)for the Participating Institutions.The Participating Institutions are The University of Chicago,Fermilab,the Institute for Advanced Study,the Japan Participation Group,The Johns Hopkins University,Los Alamos National Laboratory,the Max-Planck-Institute for Astronomy(MPIA),the Max-Planck-Institute for Astrophysics(MPA),New Mexico State University,Princeton University,the United States Naval Observatory,and the University of Washington.

It is a pleasure to thank SDSS colleagues for supplying some of the?gures.I would particularly like to thank Donald York for his careful reading of the manuscript.

References

[1]Bahcall N.A.et al.,2002,submitted to ApJ(astro-ph/0205490)

[2]Becker,R.H.,White,R.L.&Helfand,D.J.,1995,ApJ,450,559

[3]Blanton M.,et al.,2001,AJ,121,2358

[4]Blanton M.R.,Lupton R.H.,Maley F.M.,Young N.,Zehavi I.,Loveday J,2001,submitted to

AJ

[5]Burgasser A.J.,2001,astro-ph/0101242

[6]Colless M.,et al.,2001,MNRAS,328,1039

[7]Connolly A.,et al.,2001,submitted to ApJ(astro-ph/0107417)

[8]Disney,M.J.,1976,Nature,263,573

[9]Dodelson,S.,et al.,2001,submitted to ApJ(astro-ph/0107421)

[10]Eisenstein,D.J.,et al.,2001,AJ,122,2267

[11]Fan,X.et al.,2001,AJ,122,2833

[12]Fong,R.,Hale-Sutton,D.&Shanks,T.,1992,MNRAS,257,650

[13]Fukugita,M.,et al,1996,AJ,111,1748

[14]Gunn J.E.,et al,1998,AJ,116,3040

[15]Hawley L.S.et al.,2002,AJ,123,3409

[16]Hogg D.W.,Finkbeiner D.P.,Schlegel D.J.,Gunn J.E.,2001,AJ,122,2129

[17]Hull C.L.,Limmongkol S.,Siegmund W.A.,1994,Proc.SPIE,2199,852

[18]Ivezi′c Z.,et al.,2001,AJ,122,2749

[19]Limber,D.N.,1953,ApJ,117,134

[20]Lin,H.,et al.,1999,ApJ,518,533

[21]Loveday,J.,Maddox,S.J.,Efstathiou,G.,&Peterson,B.A.,1995,ApJ,442,457

[22]Maddox,S.J.,Efstathiou,G.,Sutherland,W.J.&Loveday,J.,1990,MNRAS,242,43P

[23]Maddox,S.J.,Efstathiou,G.,&Sutherland,W.J.,1996,MNRAS,283,1227

[24]Maddox,S.J.,Sutherland,W.J.Efstathiou,G.,&Loveday,J.,1990,MNRAS,243,692

[25]McKay T.A.,et al.,2001,astro-ph/0108013

[26]Newberg H.J.et al.,2002,ApJ,569,245

[27]Petrosian,V.,1976,ApJ,209,L1

[28]Pier J.R.et al.,2002,submitted to AJ

[29]Richards G.T.et al.,2002,AJ,in press

[30]Schechter,P.L.,1976,ApJ,203,297

[31]Schlegel,D.J.,Finkbeiner,D.P.&Davis,M.,1998,ApJ,500,525

[32]Scranton R.,et al.,2001,submitted to ApJ(astro-ph/0107416)

[33]Shapley,H.&Ames,A.,1932,Annals of the Harvard College Observatory,88,No.2

[34]Smith J.A.,et al,2002,AJ,123,2121

[35]Stoughton C.et al.,2002,AJ,123,485

[36]Strauss M.A.et al.,2002,AJ,in press(astro-ph/0206225)

[37]Szalay A.S.et al.,2001,submitted to ApJ(astro-ph/0107419)

[38]Tegmark M.,et al.,2002,ApJ,571,191

[39]Waddell,P.,Mannery,E.J.,Gunn,J.,Kent,S.,1998,Proc.SPIE,Vol.3352

[40]York D.G.,et al.,2000,AJ,120,1579

[41]Zehavi I.,et al.,2002,ApJ,571,172

Jon Loveday is a Lecturer in the Astronomy Centre,University of Sussex.He has been interested in galaxy surveys and observational cosmology since studying for his PhD in Astronomy at the University of Cambridge.After spending three years in Australia,he became one of the?rst SDSS participants while at Fermilab and then the University of Chicago.He is still occasionally seen carrying a violin case.

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