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  • Title: 2dF QSO Redshift Survey (2QZ)
    Descriptive info: .. The 2dF QSO Redshift Survey (2QZ).. The 2QZ is Finished!.. See.. `Latest News'.. for details.. Before jumping into all the finer details of teh survey, a brief.. non-astronomer's guide.. to redshift surveys is available.. See also our brief summary of.. 2QZ basics.. We are using the.. AAT.. Two-Degree Field.. (2dF) to obtain redshifts for > 25000.. B.. 21 QSOs in.. two 75 5 declination strips.. in the South Galactic Pole and in an equatorial region at the  ...   primordial fluctuation power spectrum out to COBE scales, (2) to determine the rate of QSO clustering evolution in the non-linear and linear regimes and hence obtain new limits on the value of.. and the bias parameter, (3) to apply a powerful geometric method to measure.. A.. more detailed.. discussion of the above paragraph is available.. The 2QZ team.. (Tue Jun 17 18:50:19 BST 2008 by.. ">RJS.. ).. This site is kindly hosted by.. Astrophysics Research Institute.. of.. Liverpool JMU..

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  • Title: 2dF QSO Redshift Survey ( Redshift Wedge Plot )
    Descriptive info: We plot here a point for each of our QSOs so far observed, graphically illustrating the power of this survey to probe clustering on very large scales.. Download.. a.. postscipt.. or.. larger jpeg.. file of the latest wedge plot.. |.. Survey Status.. Home.. Contact Addresses.. Robert J.. Smith,.. ">rjs@astro.. livjm.. ac.. uk.. Last modified: Fri Mar 30 11:20:30 BST 2001..

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  • Title: 2dF QSO Redshift Survey (2QZ) Results
    Descriptive info: This is simply to be a grab bag of recent preliminary results, plots and points of interest which we want to make public.. Unless stated otherwise, anything which appears here should be considered a work in progress.. For actual published results, please see our list of.. 2QZ publications.. See also.. Whole Survey Stacks.. below.. From our.. first.. observing run.. QSOs in the rest frame.. This.. PS plot.. and this.. gif version.. show ten QSOs at various redshifts each projected back to its rest wavelength and then compared with a composite spectrum.. They demonstrate how we observe a different section of the QSO spectrum depending on its redshift.. For very distant objects the ultra-violet part of the spectrum has been redshifted into the visible and is what we observe.. For very low redshift QSOs, we can actually observe the visible wavelengths.. The composite at the bottom of the figure was created by adding together 10000 spectra, thereby creating one mean spectrum which covers the full wavelength range.. The ten spectra are available individually, in their observed frame below.. Various.. example spectra.. in gif and PS formats.. Postscript plot.. of some QSOs and.. galaxies.. taken from an.. AAO Newsletter.. article.. This is currently an area of very active work and we hope new results will appear here soon.. For the time being, we suggest you look at the.. on-line version of the talk.. Scott Croom gave at the 1999 Coral Sea Cosmology meeting.. Please bear  ...   of redshift is obvious and over the redshift range 0 35.. The OLF results are published in.. The 2dF QSO Redshift Survey - I.. The Optical Luminosity Function.. , B.. J.. Boyle, T, Shanks, S.. M.. Croom, R.. Smith, L.. Miller, N.. Loaring, C.. Heymans, MNRAS accepted,.. astro-ph/0005368.. Our observed.. magnitude.. ,.. redshift.. and.. spatial.. distributions.. We do not only find QSOs.. This plot shows UBR catalogue.. contamination as a function of colour.. Example Spectra.. above contain a few examples of non QSO objects.. Survey geometry `glass wedge' plots.. Version 1.. with `cue-ball' Galactic bulge.. Version 2.. with nebulous Galactic bulge.. The latest wedge plot.. Whole Survey Stacks.. Rest frame, 10000 QSOs, monochrome, features labelled, 640x512 pix.. Observed frame, 10000 QSOs, monochrome, features labelled, 640x512 pix.. Observed frame, 20000 QSOs, 8bit colour gif, unlabelled, 640x336 pix.. Observed frame, 20000 QSOs, gzipped 24bit colour tif, unlabelled, 2000x1050 pix, 6Mb!!.. Observed frame, 20000 QSOs, 24bit colour jpg, unlabelled, 2000x1050 pix.. Rest frame, 20000 QSOs, 8bit colour gif, unlabelled, 640x336 pix.. Rest frame, 20000 QSOs, gzipped 24bit colour tif, unlabelled, 2000x1050 pix, 6Mb!!.. Rest frame, 20000 QSOs, 24bit colour jpg, unlabelled, 2000x1050 pix.. Rest frame, 10000 QSOs, 24bit colour tif, features labelled, 640x512 pix.. Rest frame, 10000 QSOs, 8bit colour gif, features labelled, 1142x871 pix.. These give a feeling for what I can easily produce.. Let me know if you need a particular combination of resolution, colour depth, labelling etc.. (Fri Aug 31 11:45:55 BST 2001 by..

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  • Title: 2dF QSO Redshift Survey (Progress)
    Descriptive info: 2dF QSO Redshift Appeal.. Every Spectrum Helps: Please give generously.. Final.. Current.. number of redshifts:.. (19/06/2002).. 02/07/02.. On-line postage stamp images of all sources have been changed to be the.. SuperCOSMOS Sky Surveys.. (see also.. SuperCOSMOS Science Archive.. ) blue plates rather than from the STScI/DSS blue plate scans.. Both FITS and jpeg versions are available.. Note that the old DSS images (as can still be found on the CD-ROM data release 1) were gif format.. The SuperCOSMOS scans are slightly higher resolution, so the new images are rather larger even though they still cover a 2 arcmin box.. Images may be extracted via the.. spectroscopic database search page.. 25/06/02.. New feature on the.. You can now search for objects by name.. Objects will be extracted for which the entered text is a substring of the published 2QZ object name (e.. g.. , J012330.. 6-294840).. 19/06/02.. The completion of the 2QZ and 2dFGRS has been marked by the production of some rather nice plaques for the two teams.. Pictures can be seen in an.. AAO press release.. 13/04/02.. On 11 April 2002 the final observations for the 2QZ were taken at the AAT.. There is of course still a huge amount of work to be done before the public data release, but this puts us one big step closer to that goal.. Many thanks go to all the AAO staff and collaborators who have helped us get this far.. We are currently working on the final data release which will be made publicly available as soon as it is ready.. We are currently aiming for first quarter 2003.. Further announcements to follow.. 16/04/01.. The data CDROMs are now available.. Please see you nearest 2QZ representative! The MNRAS paper describing the data release will be published this week.. 29/03/01.. Public Data Release:.. The paper describing the first public data release from the survey has now been accepted by Monthly Notices and will appear in vol 322, pink pages 29.. CD-ROMs (designed for Linux/UNIX machines) containing the spectra, a custom catalogue search tool and various other survey information have been produced and will be available from survey team members as soon as the paper is published.. 20/06/00.. Having broken the 10 000 QSO barrier, the survey progress was recently reviewed by both ATAC and PATT and it was agreed that pending a timely data release, the allocation committees would continue to support the 2dF redshift surveys.. We are now hoping to have the surveys complete inside two years, with a public data release in the first half of 2001.. Details are still to be confirmed.. For the time being, the number of QSOs is creeping up slowly and we are continuing to get shocking weather for our observing runs.. 28/10/99.. I have been receiving complaints about the lack of new news, but there has not really been much to add, other than to say we are going well.. Observations are continuing and the weather has been kinder, if not wonderful.. 2dF itself has been behaving well.. There have been problems with halation on the dewar window and a bad contact sporadically leading to the loss of CCD2, but these are fixed or at least `under cotrol'.. Recently there have been some exciting develpments.. The science grade CCD has finally been installed in spectrograph 2 and new ADC control software also seems to have greatly improved its performance.. These two enhancements appear to have improved our spectroscopic completeness to over 90%, but time will tell if this is maintained.. The recent.. Coral Sea  ...   the best data to date, but we shall leave it to the 2dF team to summarise.. current status.. and outstanding problems.. 19/11/97.. With the recent availability of the full 400 fibre system on 2dF, we are suddenly making amazing progress.. During the.. October 1997.. run the 2dF team were able to observe and re-configure simultaneously and despite the poor weather, just over 1000 QSO candidates were observed.. (Thanks to them again for all their effort on our behalf) We are still in the process of measuring all the redshifts, but the progress bar above is really starting to grow.. Example Spectra and Preliminary Results.. This section has been superceded.. See our new.. results page.. Data from another early.. commissioning run.. Still more exmaples.. These 10 spectra were selected to be of better than average quality and are drawn from across the full redshft range of the survey.. They are therefore better regarded as `example QSOs' than as samples of the 2QZ.. Postscript figures.. On-screen GIF plots.. Spectroscopic Data Release 1.. 31/03/01.. A few cosmetic updates and changes.. The new URL should now be working and all future access to the web page be via.. http://www.. 2dfquasar.. org.. 27/06/00.. I have added a.. I would consider this much more a `work in progress' page than just links to published papers.. At the moment there is little there, but I would gratefully accept submissions from team members of things to include.. These can either just be interesting plots about which I can write a brief public explanation, or write up a whole page I can simply link to.. 04/06/00.. Survey team members can now get the FITS and gif postage stamp images of all 2QZ sources from the database extraction web form.. 30/05/00.. Some more.. have been included.. Full QSO+galaxy sdf files can now be extracted from the database by team members.. See the.. archive page.. 20/05/00.. Extracting data from the archive just got easier again.. Instructions are.. here.. Remember, this is for survey member only.. You can expect an announcement about schedule for public data release `.. soon.. '.. More information.. on how survey members can extract the data they need from the archive.. 24/07/99.. Putting together the.. HTML proceedings for the Coral Sea Conference.. has given me the excuse to put up a few more pretty colour plots.. There are updated.. N(m) and N(z) histograms.. , and a new.. wedge plot.. showing the QSOs and the 2dF galaxies.. There is also a map of.. survey sky coverage.. and a figure illustrating the UBR catalogue.. More importantly, I have made some changes to the.. data archive.. (survey team members only), most particularly describing.. how to extract spectra.. from the database.. 09/02/99.. Updated.. redshift wedge.. Since you are reading this, you no doubt know that the web page has moved to a new home:.. http://msowww.. anu.. edu.. au/~rsmith/QSO_Survey/qso_surv.. html.. I have also updated the.. N(z).. plot.. Greater than 1000 QSOs!.. 31/12/97.. 05/12/97.. We've added a page for the.. plot Scott has produced.. 17/10/97.. A new update on the survey QSOs'.. N(m) and N(z).. relations.. 10/10/97.. Impressive progress has been made on the 2dF instrument itself.. 2dF page.. and in particular a report on the first observing run with the full complement of.. 400 fibres.. and both spectrographs observing simultaneously.. contact addresses.. page.. 3/2/97.. The CCD photometry used for callibration of the UVX catalogue is now.. publicly available.. 31/1/97.. We have added a few more.. from more recent observing runs.. 20/11/96.. We have our very.. first spectra!.. (Tue Jul 2 15:58:17 BST 2002 by..

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  • Title: What is Redshift? (2dF QSO Redshift Survey - 2QZ)
    Descriptive info: We have attempted to write most of these web pages in such a way as to be understood by any visitor.. This site is however designed primarily as a reference for professional astronomers who are directly involved in this field of research.. Some sections therefore necessarily become very technical.. We do hope however that non-astronomers will visit and we would like them to actually profit from reading our pages.. We have therefore attempted to provide here a brief description of most of the basic concepts behind the survey, such that anyone with a good understanding of physics will understand.. Under certain conditions, like those in the nucleus of a QSO, all atoms can be made to emit light at particular wavelengths.. The precise wavelengths, or colours, at which each atom radiates are unique, which effectively gives each type of atom a sort of `finger-print'.. Hydrogen, for example has a series of emission lines seen at 6562.. 8.. Å.. , 4861.. 3Å, 4340Å, 4102.. 8Å, 4102.. 8Å, 3888.. 7Å, 3834.. 7Å and 3798.. 6Å.. This is only a representative sample.. There are many more lines.. If we see features in an object's spectrum at precisely these wavelengths, we know that Hydrogen must be present in that object.. Light is an electro-magnetic wave, just like the signal emitted by police radar speed cameras.. We can measure the speed with which a QSO is moving away from us in almost the same way as a radar gun measures the speed at which you are approaching it.. Light, sound or indeed any wave is perceived differently when it comes from a moving source.. If that source is approaching the observer, the wave is squashed up onto itself making the wavelength shorter.. For light, this makes it bluer.. For sound (e.. , an approaching fire engine siren) it makes the sound higher pitched.. For a receeding source, light gets redder and sounds get deeper.. We measure the apparent speed of a QSO by looking at features in the spectrum which we know are leaving the QSO at a particular wavelength (i.. , colour), but by the time we observe them are observed to be much redder.. This is redshift.. We define the redshift.. z.. scale such  ...   rest wavelength to show it how it was when emitted from the QSO rather than how it was observed when it reached the telescope.. For comparison there is a composite spectrum at the bottom.. The composite was created by adding together 10000 spectra, thereby creating one mean spectrum which covers the full wavelength range.. You can see how the section of the QSO spectrum which we observe changes with redshift.. For very distant objects though the ultra-violet part of the spectrum has been redshifted into the visible and is what we observe.. The light which was in the visible range when it was emitted, has now been redshifted far out into infrared where we cannot observe it.. After we have observed an object, we determine its redshift simply by comparing it to the composite at the bottom to see how we can best line up all the features to match.. We then see how far we had to slide the observed spectrum along the scale to make it match and that is the objects redshift.. For comparison, we plot below the observed spectrum for the highest redshift object above.. You can see that the shape of the spectrum is the same.. It is simply observed with longer wavelengths.. In this plot, we also label the lines to show which atoms are responsible for each one.. The atoms shown here are Hydrogen (Ly), Nitrogen (N), Silicon (Si), Carbon (C) and Helium (He).. The roman numerals signify the physical state of the atom at the time the light was emitted.. For example, this spectrum contains lines from both CIV and CIII, two different states of carbon.. If you are interested, all ten spectra are shown in their observed wavelengths.. Glossary.. : Angstrom : A unit of length which strictly is not part of standard, internationally recognised SI units.. It is however very popular among astronomers.. 1 Å = 10.. -10.. m = 0 0000001 mm.. Visible light has wavelengths in the range 4000(blue) - 7000(red) Å.. The spectra from 2dF cover a slightly wider range of wavelegth; 3500 - 8000 Å.. (This, incidently and irrelevently, is rather similar to the range visible to a goldfish.. ).. (Thu Aug 9 15:54:27 BST 2001 by..

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  • Title: 2QZ Basics
    Descriptive info: This page provides, in brief, some basic information on the 2dF QSO Redshift Survey (2QZ).. Survey area.. The 2QZ survey covers two 75 5 declination strips.. One near the South Galactic Pole at declination=-30 in the range RA=21.. h.. 40 to 03.. 15 (the SGP strip) and a second in an equatorial strip (declination=0 ) near the North Galactic Pole in the region RA=09.. 50 to 14.. 50 (the NGP or equatorial strip).. The plot below shows the position of the strips on the sky, as well as the positions of all previously known QSOs (black points; Veron-Cetty Veron 2000).. This survey area was tiled with an overlapping mosaic of 2dF fields, designed to obtain maximum coverage from the minimum number of 2dF pointings.. The list of field names and their centres can be found.. Note that the survey was constructed in a B1950 coordinate system.. Magnitude and colour limits.. The 2QZ is flux limited in the b.. J.. band.. Magnitudes were determined from.. APM.. scans of.. UKST.. photgraphic plates..  ...   dotted line.. Large blue points are previously known QSOs.. 2dF Observations.. The survey was carried out at the.. Anglo-Australian Telescope.. using the.. 2-degree Field.. multi-object spectrographic system.. Up to 400 spectra can be obtained at once using this state-of-the-art instrument.. This huge multiplex gain has allowed surveys such as the 2QZ to become a reality.. 2dF on the AAT with the primary mirror in the background.. 2dF at the AAT prime focus.. The two spectrographs are located on the outer rim of the top end ring.. A 2dF field plate configured for observation.. The fibres are back illuminated by red LEDs.. The 2dF robot fibre positioner in action.. 6dF Observations.. The brighter portion of the survey (the 6dF QSO Redshift Survey; 6QZ) was carried out at the.. UK Schmidt Telescope.. 6-degree Field.. Up to 150 spectra can be obtained at once over a 6 degree diameter field of view.. The 6dF robot positioning fibres.. A closer view of the 6dF system.. Back to.. 2QZ home.. Spectroscopic catalogue home.. (July 2003)..

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  • Title: Dunk Proceedings - 2dF QSO Redshift Survey (Survey Regions)
    Descriptive info: Small black points show all QSOs known previously before the start of this survey.. Front page.. |.. - Survey description & objectives.. ">rsmith@mso.. au.. Last modified: Fri Sep 24 11:39:02 EST 1999..

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  • Title: 2dF QSO Redshift Survey (Objectives)
    Descriptive info: 2dF QSO Redshift Survey.. Detailed description of survey objectives.. Some of the discussion included here is a little out of date.. We have now moved to.. UBR slection.. of candidates in place of the original UVX technique.. All the science justification and objectives of the survey remain unchanged.. We are proposing to use the 2dF to make a simultaneous QSO and galaxy redshift survey across two declination strips, one in the South Galactic Pole and one in an equatorial region at the North Galactic Cap.. The Southern strip will be in the same area of sky as the Durham/UKST.. B 17.. galaxy redshift survey.. QSOs will be selected by the ultra-violet excess (UVX) method and the key to the success of this proposal is the large amount of deep.. U.. plate material which we have already obtained with the UK Schmidt Telescope.. We shall observe 120 - 130 UVX QSO candidates per fibre field to.. B=21.. The area surveyed in each strip will be 75 5 and the resulting catalogue will contain 30000.. z 2 2.. QSOs.. Combined with large area galaxy redshift surveys, it will form the most comprehensive picture of the large-scale structure of the Universe in a given area of sky, with the QSOs probing the structure up to scale lengths of 1000h.. Mpc (comparable to the scales studied by COBE) and the galaxies at.. B 20.. forming a more detailed picture of the topology on scales up to 500h.. Mpc.. The Need for a.. B 21.. QSO Survey.. There are four main scientific aims of the proposed QSO redshift survey.. (1) The large-scale structure of the Universe.. Recent results demonstrating that radio-quiet QSOs exist in average galaxy clustering environments (Ellingson et al 1991, Boyle Couch 1993, Smith et al 1995 - see.. Fig.. 1.. ) provide the essential confirmation that QSOs can be used to derive important and meaningful information of the structure of the Universe at the largest scales.. Combined with the agreement between the strength of QSO and galaxy clustering at.. r 10.. h.. Mpc (Shanks Boyle 1994), these results strongly suggest that QSOs may randomly sample the optical galaxy spatial distribution.. QSOs therefore provide a very simple and direct route to the question of how galaxies are distributed on the largest scales.. There are 3 different regimes where a precise determination of the QSO clustering correlation function will provide immediate new constraints on cosmological models:.. (a) The Non - Linear Regime: (.. r.. 10h.. Mpc).. At small scales we will obtain information about the development of the non-linear regime of QSO clustering in the redshift range.. 0 5 z 2 2.. Since the Ellingson et al.. (1991) result suggests that optical QSOs randomly sample the optical galaxy distribution, this means that.. we will also be investigating the evolution of the galaxy correlation function at these depths.. In this range of redshifts, an unbiased,.. = 1, CDM model predicts that there will be substantial evolution of the correlation function,.. , at small scales (see.. 2.. ), whereas a biased CDM model predicts much less evolution in.. (as measured in comoving coordintes).. Even by combining all 700 QSOs in the existing deep (.. ) surveys (Durham/AAT+ESO/AAT+CFHT, see Shanks Boyle 1994), at present there are only 40 QSO pairs with.. From this data the suggestion is that the QSO clustering amplitude seems more consistent with comoving evolution, although the data allows only a rough correlation function amplitude to be measured for.. Mpc on the.. assumption.. of an underlying.. -.. 1 8 power-law (see.. 3.. With.. 2000.. Mpc QSO pairs available in the proposed survey, this will make possible an accurate measurement of both the amplitude ( 10%) and the slope ( 0 1) of the correlation function over the whole redshift range 0 5.. 2 2.. Further, at scales 2h.. Mpc present QSO samples contain no QSO pairs.. With a sample of 30000 QSOs we estimate (assuming.. for the QSO sample) that we should find.. QSO pairs at these scales.. At this scale we might expect clustering to be stable in proper coordinates, in which case it may follow a different evolution with.. Also on these 2h.. Mpc scales the 3-D QSO clustering evolution results can be directly compared to those obtained from deep 2-D analyses of galaxy clustering (Roche et al 1993).. By comparing the results for.. over the entire 0.. Mpc range with the predictions from cosmological N-body and hydrodynamic simulations we shall be able to discriminate between not just biased and unbiased CDM but also HDM, baryonic and low.. models.. (b) The Intermediate Linear Regime: (10.. 30h.. Here we will determine the form of the QSO correlation function at the scales where it is most sensitive to the primordial mass spectrum.. At these scales the correlation function is claimed to show excess power over what is expected for a standard CDM model, on the basis of the projected APM correlation function (Maddox et al.. 1991) and, at a less significant level, on the basis of the IRAS redshift survey correlation function.. In this range of scales, QSO surveys are becoming highly competitive with galaxy redshift surveys in terms of the statistical accuracy of the correlation function since they are effectively a very sparse sampled dataset (Kaiser 1987) with each QSO bringing almost completely independent correlation function information.. Currently the QSO correlation function errors in this range are 0 15 from the 700 QSOs in the Durham/AAT+ESO+CFHT surveys and show insignificant excess power over that expected for CDM (see Mo Fang 1993).. However, a correlation function as flat as the APM result is also not significantly excluded.. In the proposed 30000 QSO survey this error will reduce to 0 02 and we will be able to discriminate between the APM and the standard CDM correlation function slopes at the.. level (see.. 4.. This is a powerful example of what will be possible with a QSO correlation function measured to this accuracy in this intermediate regime.. In.. we also show the different correlation function shapes expected for a canonical CDM power spectrum form with primordial index running between 0 5.. n.. 1 5, the range favoured by consideration  ...   clustering in the redshift and angular directions.. Under the reasonable assumption that the QSO small-scale clustering will be spherically symmetric at least in the average, the extent of the QSO correlation function should be the same in both directions.. However, the distance between a pair of QSOs measured in the line of sight from the redshifts has a different dependence on the cosmological parameters from the distance measured in the angular direction.. By demanding that these two distances are in the average the same, a powerful cosmological test emerges.. Now in the case of.. models the difference between the 2 extents is only small for values of.. in the range 0.. 0 5 (see.. 6.. However, the difference in extents for models with.. 0 can be much more significant.. For example, in the interesting case of a zero spatial curvature model with.. 0 the result is strikingly different from the conventional case.. The current constraints on.. from this method are poor, since there are only 40 correlated QSO pairs with.. However in the proposed survey the number of pairs would rise to.. and then, according to Phillipps (1994), there is the possibility of an almost exact determination of.. from this method.. Redshift measurement errors and random small-scale peculiar velocities are not a problem for this method, since their effects are small if the extents are measured over 10h.. comoving Mpc.. Of course, it should also be noted that if the result is consistent with.. and 0.. 0 5 then this will be a non-negligible test of the GR theory that relates the angular and redshift distance measurements.. Most of the examples given above discuss the measurement of QSO clustering using the correlation function, primarily for ease of comparison with existing analyses.. However, we will also make extensive use of other statistics to measure QSO clustering e.. power spectrum, higher order (3-point, 4-point) correlation functions, counts in cells etc.. to extract the maximum information content from the proposed survey.. (4) The QSO Luminosity Function.. The 30000 QSOs in this survey will allow us to determine the QSO luminosity function (LF) and its evolution at.. 2 2 with unprecedented accuracy.. This represents the first self-consistent determination of the QSO LF based on a single sample selected over the magnitude range.. 17 B 21.. which encompasses the `break' in the LF.. Previous estimates of the QSO LF have relied on combining different surveys with different magnitude limits to derive a picture of the full QSO LF (Boyle et al.. 1988).. In particular, we will investigate the recent observation from.. B 18 5.. QSO surveys that the bright end slope of the QSO LF steepens with redshift (Hewett et al.. 1993, Goldschmidt et al.. 1993), implying that `pure luminosity evolution' is no longer a valid description of redshift dependence of the QSO LF.. we will have over 500 QSOs in our sample and can critically test whether such a steepening occurs in the LF based on a single homogeneous survey selected at magnitudes both brighter and fainter than.. B=18 5.. From this survey we will also be able to determine the space density and evolution of intrinsically rare classes of QSO e.. Broad Absorption Line (BAL) QSOs, damped Ly.. QSOs and QSOs with strong metal absorption line systems.. Based on a BAL QSO fraction of 5-10%, we expect to identify over 1500 BAL QSOs in this survey.. This is sufficient to derive an accurate picture of their space density and evolution at.. , and will provide vital clues to the physical nature of such systems.. We will also identify.. QSOs with.. 1 9 z 2 2.. , the redshift range over which we will be able to identify candidate damped Ly.. systems.. Assuming that 2-5% of QSOs exhibit damped Ly.. (Pettini, private comm.. ), we will identify 100-250 such systems in the survey, providing valuable data towards an accurate determination of the space density of the galactic disks at.. thought to be responsible for the damped Ly.. lines.. Similar information should be derived for the significant number of strong metal-line absorption systems which will also be identified in this survey.. With over 6000 bright (.. B 19 5.. ) QSOs (.. /2dF field) in the final sample, the survey will also provide an invaluable source of material for future, more detailed, spectroscopic campaigns of QSOs and their absorption line systems.. In passing, we note that the survey will also yield astrophysically important information on other classes of astronomical objects.. Based on the Durham/AAT UVX survey (Boyle et al.. 1990), we expect to find over 1500 hot white dwarfs and.. distant (.. r 50.. kpc) blue horizontal branch stars.. The white dwarfs can be used to provide an accurate measure of their scale-height (Boyle 1989), possibly even as a function of spectroscopic class, and the horizontal branch stars are important tracers of the dynamics of the outer halo of our galaxy (Sommer-Larsen Christiansen 1986).. References:.. Alcock Pacynski, 1979, Nat, 283, 358.. Boyle et al.. , 1988, MNRAS, 238, 957.. Boyle 1989, MNRAS, 240, 533.. , 1990, MNRAS, 243, 1.. Boyle, Jones Shanks, 1991, MNRAS, 251, 482.. Boyle Couch, 1993, MNRAS, 264, 604.. Broadhurst et al.. , 1990, Nat, 343, 736.. Cole et al.. , 1994, 267, 785.. Ellingson et al.. , 1991, ApJ, 371, 49.. Fisher et al.. , 1994, MNRAS, 266, 219.. Goldschmidt et al.. , 1993, MNRAS, 256, 65P.. Hamilton 1991, ApJ, 374, L1.. Hewett et al.. , 1993, ApJ, 406, L43.. Holtzmann 1989, ApJS, 71, 1.. Kaiser, 1987, MNRAS, 227, 1.. Kirshner et al.. , 1994, preprint.. Maddox et al.. , 1991, MNRAS, 242, 43P.. Mo Fang, 1993, ApJ, 410, 493.. Peebles 1980, The Large-Scale Structure of the Universe.. Phillipps, 1994, MNRAS, 269, 1077.. Roche et al.. 1993, MNRAS, 263, 360.. Ryden et al.. 1989, ApJ, 340, 647.. Shanks Boyle, 1994, MNRAS, 271, 753.. Smith, Boyle Maddox, 1995, MNRAS, 277, 270.. Somer-Larsen Christiansen 1986, MNRAS, 219, 537.. This document was prepared with the assistance of.. LaTeX2HTML.. If you are looking for.. Greek.. symbol.. gifs to in-line in your HTML documents, you are welcome to the ones I created in writing this page.. View the figures..

    Original link path: /objectives.html
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  • Title: 2QZ data release
    Descriptive info: Welcome to the 2dF QSO Redshift Survey (2QZ) data release web page.. You may be viewing this directly from our web site or running locally from the 2QZ CD-ROM.. The offical 2QZ web page can be found at.. www.. The 2QZ team (July 2003)..

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  • Title: 2QZ Photometric (ubr) Catalogue release
    Descriptive info: Welcome to the 2dF QSO Redshift Survey (2QZ) photometric catalogue release web page.. This page contains the survey input catalogue an some other related data.. For a full description see.. MNRAS (accepted).. See also the.. spectroscopic data release.. The 2QZ web page can be found at.. (Plates, holes, astrometry etc.. ).. (External link).. (April 2001)..

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  • Title: 2dF QSO Redshift Survey (UBR Catalogue)
    Descriptive info: The UBR Input Catalogue.. Candidate QSOs for spectroscopic confirmation have been identified by.. colour selection techniques.. from digital scans of wide-field photographic plates taken with the.. UK Schmidt Telescope.. Plates in the ultra-violet (u), blue (b) and red (r) bands were used, allowing selection by u-b and b-r colours.. Candidates were also required to show stellar image profiles on the blue plate and are magnitude limited at b.. Above is a picture of the UBR input catalogue.. A paper detailing the properties and creation of the data set is in preparation, but for the time being, a brief discussion of  ...   survey strips are arranged on the sky and the positions of all previously known QSOs.. Observational experience has shown that over 50% of the candidates really are QSOs.. We have a plot showing the.. catalogue contamination as a function of colour.. If you are interested in using this data set for your own research, keep an eye on this site.. We plan to make the catalogue available in the near future.. Photometry.. Much of the CCD photometry used to callibrate this catalogue is publicly.. available.. We include a brief description with the data.. (Thu 19 Jun 2008 10:26:28 PDT by..

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  • Archived pages: 98