The Lyman-Alpha Forest at 1.5 z 4
a r X i v :a s t r o -p h /0101005v 2 2 M a y 2001
A&A manuscript no.
(will be inserted by hand later)
ASTRONOMY
AND
ASTROPHY SICS
Send o?print requests to :T.-S.Kim ?
Based on public data released from the UVES commission-ing at the VLT/Kueyen telescope,ESO,Paranal,Chile.??
Table A.1,Table A.2and Table A.3are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5).
are constant in the interval 1.5
3.
The observed cuto?Doppler parameter at the ?xed column density N H i =1013.5cm ?2,b c,13.5,shows a weak increase with decreasing z ,with a possible local b c,13.5maximum at z ～2.9.
4.The two-point velocity correlation function and the step optical depth correlation function show that the clustering strength increases as z decreases.
5.The evolution of the mean H i opacity,
τH i ∝(1+
z )3.34±0.17,at 1.5 6. The baryon density,?b ,derived both from the mean H i opacity and from the one-point function of the ?ux is consistent with the hypothesis that most baryons (over 90%)reside in the forest at 1.5 Key words:Cosmology:observations –quasars:Ly αforest –quasars:individual HE0515–4414,HE2217–2818,J2233–606,HS1946+7658,Q0302–003,Q0000–263 2Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 HE0515–441414.9 1.7193050–386019000Dec.14,18,1999Reimers et al.(1998) J2233–60617.5 2.2383050–386016200Oct.8-12,1999 J2233–6063770–498012300Oct.10-16,1999 HE2217–281816.0 2.4133050–386016200Oct.5–6,1999Reimers et al.(1996) HE2217–28183288–452210800Sep.27–28,1999 Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 bined with weighting corresponding to their S/N and re- sampled with a0.05?A bin.The S/N varies across the spec- trum,increasing towards longer wavelengths for a given instrumental con?guration.The typical S/N per pixel is ～20–50for HE0515–4414at3090–3260?A,～25–40for J2233–606at3400–3850?A and～45–50for HE2217–2818 at3550–4050?A. The combined spectra were then normalized locally using a5th order polynomial?t.There is no optimal method to determine the real underlying continuum of high-z QSOs at wavelengths blueward of the Lyαemission due to high numbers of Lyαabsorptions.The normaliza- tion of the spectra introduces the largest uncertainty in the study of weak forest lines.However,considering the high resolution of our data and the relatively low number density of the forest at z～2,the continuum uncertainty should be considerably less than10%. 3.The Voigt pro?le?tting Conventionally,the Lyαforest has been thought of as orig- inating in discrete clouds and has thus been analyzed as a collection of individual lines whose characteristics can be obtained by?tting the Voigt pro?les.From the line?tting, three parameters are derived:the redshift of an absorption line,z,its Doppler parameter,b(if the line is broadened thermally,the b parameter gives the thermal temperature of a gas,b≡ 4Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 Fig.1.The spectrum of HE2217–2818superposed with the Voigt pro?le?t.The residuals(the di?erences between the observed and the?tted?ux)shown in the bottom part of each panel are shifted by?0.25. Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 Fig.2.The spectrum of J2233–606superposed with the Voigt pro?le?t.The residuals(the di?erences between the observed and the?tted?ux)shown in the bottom part of each panel are shifted by?0.25. 6Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 , Fig.3.The spectrum of HE0515–4414superposed with the Voigt pro?le?t.The residuals(the di?erences between the observed and the?tted?ux)shown in the bottom part of each panel are shifted by?0.25. al.(1995)withχ2～1and the errors associated with the ?tted parameters are not published. The results of pro?le?tting are known to be sensitive to the data quality as well as to the characteristics of the ?tting program.As a consequence,comparing line lists obtained with di?erent criteria is not usually straightfor- ward.Due to the use of a di?erent?tting program,the line list of Q0302–003at z～2.9should be treated with caution when combined with other line lists.A system- atic di?erence in b and N H i from VPFIT can introduce a slightly di?erent behavior of the Lyαforest at z～2.9. While the di?erence would not change the study of the line number density or the correlation function signi?cantly,it can a?ect the determination of a lower cuto?b envelope in the N H i-b diagrams.Furthermore,the six QSOs in Ta- ble2cover the Lyαforest at1.54 fairly regular spacing.There is very little overlap between the Lyαforests of the di?erent QSOs and the e?ects of cosmic variance in the individual lines of sight might be important. 4.1.The di?erential density distribution function The di?erential density distribution function,f(N H i),is de?ned as the number of absorption lines per unit ab- sorption distance path and per unit column density as Table2.Analyzed QSOs HE0515–4414 1.7193090–3260 1.54–1.680.365 J2233–606b 2.2383400–3850 1.80–2.17 1.104 HE2217–2818 2.4133550–4050 1.92–2.33 1.286 HS1946+7658c 3.0514252–4635 2.50–2.81 1.157 Q0302–003d 3.2904410–5000 2.63–3.11 1.878 Q0000–263e 4.1275450–6100 3.48–4.02 2.540 2 [(1+z)2?1]for q o=0or as X(z)≡2 Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 7 Fig. 4shows the observed log f (N H i )as a function of log N H i for di?erent redshifts.The dotted line represents the incompleteness-corrected f (N H i )at z ～2.8from Hu et al.(1995),i.e.f (N H i )=4.9×107N ?1.46 H i .Note that the apparent ?attening of the slope towards lower col-umn densities in the observed log N H i -log f (N H i )diagram is caused by line blending and limited S/N,i.e.incom-pleteness,which becomes more severe at higher z .For incompleteness-corrected f (N H i )at z >2.5(Hu et al.1995;Lu et al.1996;Kim et al.1997),this apparent ?at-tening disappears.The incompleteness-corrected f (N H i )at z ～2.8over N H i =1012.5?16cm ?2is similar to the incompleteness-corrected f (N H i )at z ～3.7(Lu et al.1996)and at z ～3.2(Kim et al.1997)over the same column density range.The amount of incompleteness ex-trapolated from at z >2.5(Hu et al.1995;Lu et al.1996;Kim et al.1997;Kirkman &Tytler 1997)becomes negli-gible at z <2.4and we assume the observed f (N H i )as representative of the actual f (N H i )at z <2.4. In the column density range N H i =1012.5?14cm ?2,the observed f (N H i )at z <2.4is in good agree-ment for the di?erent QSOs and also agrees with the incompleteness-corrected f (N H i )at 2.6 law for N H i ～>1014cm ?2 and that the column density at which the deviation from a single power-law starts decreases as z decreases.The deviation from the single power-law in f (N H i )is evident in Fig.4.While the forest at z ～3.7is still well approximated by a single power-law over N H i =1014?16cm ?2,the forest at z <2.4starts to deviate from the power law at N H i ≥1014.1cm ?2with a decreasing number of lines at N H i =1014?16cm ?2. Table 3lists the parameters of a maximum-likelihood power-law ?t to various column density ranges.These col-umn density ranges are selected for comparison with the previous observational results of Kim et al.(1997)and Penton et al.(2000)and with simulations of Zhang et al.(1998)and Machacek et al.(2000).At z ～2.1,the slope βis approximately 1.4in the interval N H i =1012.5?14cm ?2and 1.68in the interval N H i =1014?16cm ?2,i.e.the slope is steeper for higher column density clouds.At z ～1.61,the slopes β～1.70–1.72are steeper for both column density ranges.This indicates that the slope of f (N H i )increases from z ～2.1to z ～1.6.Assuming a curve of growth with b =25±5km s ?1,Penton et al.(2000)found that the slope of f (N H i )at z ～0.036over N H i =1012.5?14cm ?2and over N H i =1014?16cm ?2is β=1.72±0.06and β=1.43±0.35,respectively.The slopes over N H i =1012.5?14cm ?2are steeper at z ～0.036and at z ～1.6than at z >1.8,and suggest that the incompleteness correction at z >1.8might be underes-timated or that the slope becomes intrinsically steeper Fig.4.The di?erential density distribution function as a function of log N H i without the incompleteness correction due to line blending and limited S/N.The vertical error bars represent the 1σPoisson errors. at z <1.8.The slopes over N H i =1012.8?14cm ?2and N H i =1014?16cm ?2are in agreement with the ones found by Kim et al.(1997)at z ～2.3.However,our measure-ment of β=1.48±0.15at z ～2.1(only from HE2217–2818and J2233–606)over N H i =1013.1?14.5cm ?2is lower than the previous determination of β=1.79±0.10over the same column density range at z ～1.85by Kulkarni et al.(1996). While these observed βvalues at 1.5 4.2.The evolution of the line number density The line number density per unit redshift is de?ned as dn/dz =(dn/dz )0(1+z )γ,where (dn/dz )0is the local comoving number density of the forest.For a non-evolving population in the standard Friedmann universe with the 8 Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 Table 3.The power-law ?t of the distribution functions,f (N H i )=A N ?β H i 1.6110.65±0.861.72±0.1610.38±0.351.70±0.4210.85±0.741.74±0.2110.47±0.881.71±0.101.986.19±1.071.35±0.096.49±0.591.40±0.218.02±1.001.49±0.118.66±1.091.54±0.05 2.136.66±1.111.38±0.0814.48±0.651.94±0.247.80±1.051.46±0.109.05±1.141.56±0.051.94a 6.97±1.281.41±0.0610.43±0.801.68±0.158.16±1.211.50±0.079.02±1.301.57±0.03 1 Recent measurements from high-z supernovae favor the non-zero cosmological constant (Perlmutter et al.1999).When we use the mass density ?m ～0.3and the cosmological con-stant energy density ?Λ～0.7for the ?at universe as the re-sults from the supernova study favor (Perlmutter et al.1999),the line number density for the non-evolving forest can still be approximated by a single power-law dn/dz ∝(1+z )～0.71at 0 al.1997).This slope is steeper than the expected values for the non-evolving forest for a universe with ?Λ=0.7,?m =0.3and ?=1.These results suggest that the Ly αforest at N H i =1013.64?16cm ?2evolves and that its evo-lution slows down as z decreases.Interestingly,the HST data point at Despite the di?erent line counting methods between the HST observations (based on the equivalent width)and the high-resolution observations (based on the pro?le ?tting),a change of the slope in the Ly αnumber den-sity does seem to be real.The UVES observations suggest that the slow-down in the evolution does occur at z ～1.2,rather than at z ～1.7as previously suggested (Impey et al.1996;Weymann et al.1998),although the di?erent methods of line counting at higher and lower z make it a little uncertain.At least,down to z ～1.5,the number density of the forest evolves as at higher z ,which sug-gests that any major drive governing the forest evolution at z >2continues to dominate the forest evolution down to z ～1.5.Since the Hubble expansion is the main drive governing the forest evolution at z >2(Miralda-Escud′e et al.1996),the continuously decreasing number density of the forest down to z ～1.5implies that the Hubble ex-pansion continues to dominate the forest evolution down to z ～1.5. Fig.6is similar to Fig.5,except for the N H i range:N H i =1013.1?14cm ?2.The correction for incomplete-ness due to line blending is still negligible in this col-umn density range (Fig.4shows that the number of lines per unit column density over N H i =1013.1?14cm ?2is still well represented by a single power-law).Again,the square from Penton et al.(2000)is estimated from the equivalent widths with the assumed b =25km s ?1.The dot-dashed line is the maximum-likelihood ?t to the lower column density forest of the UVES and the HIRES data:dn/dz =(55.91±2.00)(1+z )1.10±0.21.At 2.4 Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 9 Fig.5.The number density evolution of the Lyαforest. The column density range N H i=1013.64?16cm?2has been chosen to allow a comparison with the HST results from Weymann et al.(1998),which are shown as open tri- angles.Filled symbols are estimated from HE0515–4414 at from HE2217–2818at star,open circles,and the diamond are taken from the HIRES data at similar resolutions by Lu et al.(1996), Kim et al.(1997),and Kirkman&Tytler(1997),respec- tively.The square and pentagons are taken from Penton et al.(2000)and Savaglio et al.(1999),respectively,over N H i≥1014cm?2.Horizontal solid lines represent the z interval over which the number density was estimated. Vertical solid lines represent the1σPoisson errors.The shaded area is the z range where UVES is extremely sen- sitive.The long-dashed line is the maximum likelihood?t to the UVES and the HIRES data at z>1.5.The UVES observations indicate that the number density evolution of the Lyαforest at z>2.4continues at least down to z～1.5and that a slope change occurs at z～1.2. range N H i=1013.1?14cm?2,the forest does not show any strong evolution. Note that the point at Kirkman&Tytler(1997)indicates a number density twice as large as than at N H i=1013.1?14.0cm?2(excluding the est,the maximum-likelihood?t becomes dn/dz=(47.77± 1.84)(1+z)1.18±0.22).Although this discrepancy could re- sult from a real cosmic variance of the number density from sightline to sightline,the number density in the in- terval N H i=1013.64?16.0cm?2from the same line of sight is in good agreement with other HIRES data.The di?er- ential density distribution function(Fig.4)and the mean H i opacity(Fig.15)towards this line of sight suggest that the discrepancy at N H i=1013.1?14.0cm?2is due to over- Fig.6.The number density evolution of the Lyαforest at the N H i range N H i=1013.1?14.0cm?2.Symbols are the same as in Fig.5.The dot-dashed line(solid line)is the maximum likelihood?t to the lower column density forest including the 2.66forest),while the dashed line represents the maximum likelihood?t to the forest at N H i=1013.64?16cm?2from Fig.5. ?tting,which,as discussed in Sect.3,may occur especially in high S/N data. As previously noticed(Kim et al.1997),the lower column density forest evolves at a slower rate than the higher column density forest.The evolutionary rate∝ (1+z)1.10±0.21would be consistent with no evolution for q o=1or mild evolution for q o=0.5.For?Λ=0.7, ?m=0.3and?=1,the Lyαforest with N H i= 1013.1?14cm?2is mildly evolving at z>1.5.The Lyα forest with N H i=1013.1?14cm?2appears more numer- ous at z～0than expected when extrapolating from the z>1.5range. 4.3.The lower cuto?b in the N H i–b distribution 4.3.1.The lower cuto?b parameter For a photoionized gas,a temperature-density relation ex- ists,i.e.the equation of state:T=T0(1+δ)γT?1,where T is the gas temperature,T0is the gas temperature at the mean gas density,δis the baryon overdensity,(ρb?ρb ( 10Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 Under the assumption that there are some lines which are broadened primarily by the thermal motion at any given column density,this equation of state translates into a lower cuto?b(N H i)envelope in the N H i–b distribution: T andδcan be derived from b and N H i.For the equation of state T=T0(1+δ)γT?1,b c(N H i)becomes log(b c)=log(b0)+(ΓT?1)log(N H i),(1) where log(b0)is the intercept of the cuto?in the log(N H i)-log b diagram and(ΓT?1)is the slope of the cuto?(Schaye et al.1999).The cuto?slope(ΓT?1)is proportional to (γT?1).This cuto?envelope provides a probe of the gas temperature of the IGM at a given z,thus giving a powerful constraint on the thermal history of the IGM(Hu et al.1995;Lu et al.1996;Kim et al.1997;Kirkman& Tytler1997;Zhang et al.1997;Schaye et al.1999;Bryan &Machacek2000;McDonald et al.2000;Ricotti et al. 2000;Schaye et al.2000). In practice,de?ning b c(N H i)in an objective manner is not trivial due to the?nite number of available absorption lines,sightline-to-sightline cosmic variances,limited S/N, and unidenti?ed metal lines.Among several methods pro-posed to derive b c(N H i),we have adopted the following three:the iterative power-law?t,the power-law?t to the smoothed b distribution,and the b distribution.We re-fer the reader to other papers for more methods to derive b c(N H i)(Hu et al.1995;McDonald et al.2000;Theuns& Zaroubi2000). In our analysis,we divide the data points into2groups: Sample A and Sample B.Sample A consists of the lines in the range N H i=1012.5?14.5cm?2with errors less than 25%in both N H i and b in order to avoid ill-?tted val-ues from VPFIT.Sample B consists of all the lines with N H i=1012.5?14.5cm?2regardless of errors.The criteria for Sample A and Sample B are chosen to compare our results with the previous results by Schaye et al.(2000) and to investigate whether it is reasonable to include the Q0302–003line list for which error estimates are not given. As no errors are available for Q0302–003,no Sample A can be de?ned at 4.3.2.The iterative power law?t Since the equation of state is a power law,it is reason-able to?t N H i–b c with one.We did so,using the boot-strap method described by Schaye et al.(1999),iterat-ing until convergence was reached.After each iteration, those points were excluded that lay more than one mean absolute deviation above the?t.Finally,the lines more than one mean absolute deviation below the?t were also taken out and the?nal power law?t,b c=c0,p NΓT?1 H i ,was carried out.The procedure was repeated over200boot-strap realizations in order to determine the full probability distribution of the parameters of the cuto?.As noted by Schaye et al.(2000),the power law?t requires over200 available lines to reach stable?t parameters. Fig.7shows the iterative power law?t in the log N H i–b distributions.The noticeable di?erence between Sample A(cross symbols)and Sample B(cross symbols and open circles)occurs at N H i≤1013cm?2.These lines usually come from blends or from weak,asymmetric absorption lines.Table4lists the?tted parameters,such as c0,p and (ΓT?1),including b c values at the?xed column density N H i=1013.5cm?2,b c,13.5,for Sample A and Sample B. The power law?t between Sample A and Sample B does not give a signi?cant di?erence except at Fig.8shows the power law?t to Sample A at z～2.1(small?lled circles;242lines from J2233–606and HE2217–28118)and at 4.3.3.The power law?t to the smoothed b distribution Bryan&Machacek(2000)presented a method to measure b c(N H i)from a power law?t to a smoothed b distribu-tion,sorting absorption lines by N H i and then dividing them into groups containing similar numbers of lines.The b distribution in each group was then smoothed with a Gaussian?lter with a smoothing constantσb: S b,j(b)= i exp(?(b i?b)2/2σ2b),(2) Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 11 Fig.7.The log N H i –b diagrams with the power law ?ts over N H i =1012.5?14.5cm ?2.Errors are not displayed.Crosses indicate the data points with errors less than 25%both in N H i and b (Sample A),while open circles indicate the lines with errors greater than 25%(Sample B consists of crosses and open circles together).At Fig.9shows the log N H i –b diagram at each z with the b c (N H i )points for each group (?lled circles)measured from the smoothed b distributions.We use the smoothing constant σb =3km s ?1.However,S b,j (b )is largely in-sensitive to the smoothing constant.In general,30lines were included in each group except for the last group at higher N H i for which typically smaller numbers of lines were available.For this same reason,at groups of ～16lines were used.The solid line represents the robust least-squares power law ?t to ?lled circles: b c (N H i )=c 0,s N ΓT ?1H i .Table 5lists the parameters of the power law ?t to the smoothed b distributions.We ?nd that the power law ?t to the smoothed b distri-bution produces in general a lower intercept and a steeper slope than the iterative power law ?t.It also produces smaller b c,13.5values.Direct comparison of Fig.9with Fig.7indicates that b c (N H i )measured from the smoothed b distribution can be considered as a lower limit on the real b c (N H i ),while b c (N H i )from the iterative power law ?t can be considered as an upper limit on the real b c (N H i ). 12Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 Table4.The power law?t to the N H i–b distributions 1.6147?0.92±0.090.17±0.0124.5± 2.456?0.87±0.100.17±0.0124.9±1.1 1.98103?0.49±0.110.14±0.0121.4±0.5146?0.43±0.120.13±0.0121.4±0.6 2.131390.11±0.080.09±0.0120.1±0.6181?0.70±0.110.15±0.0120.6±0.5 2.66140?0.55±0.100.14±0.0119.6±1.1204?0.13±0.100.10±0.0118.7±0.5 2.87----223?0.89±0.080.16±0.0120.4±0.8 3.752090.51±0.060.06±0.0118.7±1.22710.71±0.100.04±0.0117.1±0.9 2.1c242?0.22±0.080.11±0.0119.6±0.6327?0.73±0.080.15±0.0120.4±0.5 2.1d156?0.64±0.130.15±0.0121.2±0.7187?0.78±0.120.16±0.0120.9±0.6 3.75e1880.09±0.100.09±0.0118.9±1.0233?0.06±0.090.10±0.0118.1±0.9 (km s?1) a For Sample B since Sample A cannot be de?ned. b At N H i=1012.5?14.5cm?2for J2233–606and HE2218- 2817. c At N H i=1013?14.5cm?2for J2233–606an d HE2218-2817. d At N H i=1013?14.5cm?2. As with the iterative power law?t,b c,13.5measured from the smoothed b distribution increases continuously as z decreases,except at 4.3.4.The b distributions Assuming that absorption lines arise from local optical depth(τ)peaks and that lnτis a Gaussian random vari-able,Hui&Rutledge (1999)derived a single-parameter b distribution: dn/db=B HR bσ4 b4 ),(3) where n is the number of absorption lines,B HR is a con-stant and bσis a parameter determined by the average amplitude of the?uctuations and the e?ective smoothing scale. Fig.10shows the observed b distributions at each z. The noticeable di?erence between Sample A(solid lines) and Sample B(dot-dashed lines)occurs at b≤20km s?1 or b≥40km s?1.These unphysical lines are usually in-troduced by VPFIT to?t noises so that the overall pro?le of H i forest complexes could be improved.The dashed line represents the best-?tting Hui–Rutledge b distribu-tion,while the dotted line represents the b parameter for which the Hui-Rutledge b distribution function vanishes to 10?4,b HR,i.e.the truncated b value for the Hui-Rutledge b distribution function.The parameter b HR cannot be con-sidered equivalent to the cuto?b c since it is derived from the b distribution without assuming the b c dependence on N H i.It is more sensitive to smaller b values in the b dis-tribution,which are in general coupled with lower N H i. Table6lists the relevant parameters describing the Hui-Rutledge b distribution for Sample A,such as the constant B HR,bσ,b HR and the median b values at di?erent column density ranges. It is hard to specify subtle di?erences among the b distributions:while the modal b value and the b HR value have a minimum at Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 13 Fig.8.The log N H i –b diagrams with the power law ?ts at z ～2.1(only for J2233–606and HE2217–2818;small ?lled circles)and at in part due to a di?erent ?tting program and in part due to a lack of information on the errors.Other parameters,such as b σ,b HR ,and σ(b ),appear to be fairly constant with z . Fig.11shows the b distribution with z .This diagram does not assume a b c dependence on N H i ,but is sensitive to a local b c (N H i )variance.At z <3.1,there is no clear indication of the behavior of the lower cuto?b values as a function of z .However,there is a clear indication of a trend with z of the lower cuto?b values over 3.5 4. Fig.9.The log N H i –b diagrams for Sample A at each z (Sample B at Table 6.The parameters of the b distributions 1.617.3723.011 2.6128.1434.561.987.982 3.8313.0426.0429.102.137.4623.6112.9525.3429.572.66 6.822 4.0913.2528.3030.102.877.0927.751 5.3028.7434.053.75 6.7222.4112.3128.9030.70 14Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 , Fig.10.The b distribution of the Lyαforest at each z. While solid lines are for Sample A,dot-dashed lines are for Sample B(no Sample A at and the dotted line represent the best-?tting Hui-Rutledge function and b HR,respectively.The b med value in the pan- els indicates the median b value at the corresponding z for Sample A.The number in parentheses indicates the1σ(b) value from the Gaussian distribution. to compute the two-point velocity correlation function, ξ(?v).The correlation function compares the observed number of pairs(N obs)with the expected number of pairs(N exp)from a random distribution in a given ve- locity bin(?v):ξ(?v)=N obs(?v)/N exp(?v)?1,where ?v=c(z2?z1)/[1+(z2+z1)/2],z1and z2are redshifts of two lines and c is the speed of light(Cristiani et al.1995; Cristiani et al.1997;Kim et al.1997). Studies of the correlation function of the Lyαforest have generally led to con?icting results even at similar z. Some studies?nd a lack of clustering(Sargent et al.1980 at1.7 al.1994at z～4),while others?nd clustering at scales ?v≤350km s?1(Webb1987at1.9 1995at z～2.8;Kulkarni et al.1996at z～1.9;Lu et al. 1996at z～3.7;Cristiani et al.1997at z～3.3). Fig.12shows the velocity correlation strength at?v< 4000km s?1.To obtain su?cient statistics,the analy- sis was carried out in three redshift bins:1.5 Fig.11.The b distribution as a function of z for Sample A(Sample B at indicates b=20km s?1which is a N H i-independent b c at z～2.8(Hu et al.1995).Circles,crosses,diamonds,stars, triangles and squares are from HE0515–4414,J2233–606, HE2217–2818,HS1946+7658,Q0302–003and Q0000–263, respectively.There is an indication of increasing b c with decreasing z at z～3.7.At z<3.1,b c is not clearly de?ned. (HE0515–4414,J2233–606,and HE2217–2818),2.5 3.1(HS1946+7658and Q0302–003)and3.5 4.0 (Q0000–263). In our approach N exp was estimated averaging1000 numerical simulations of the observed number of lines, trying to account for relevant cosmological and observa- tional e?ects.In particular a set of lines was randomly generated in the same redshift interval as the data ac- cording to the cosmological distribution∝(1+z)γ,with γ=2.4(see Sect.4.2).The results are not sensitive to the value ofγadopted and even a?at distribution(i.e. γ=0)gives values ofξthat di?er typically by less than 0.02.Line blanketing of weak lines due to strong complexes was also accounted for.Lines with too small velocity split- tings,compared with the?nite resolution or the intrinsic blending due to the typical line widths–the so-called“line- blanketing”e?ect(Giallongo et al.1996),were excluded in the estimates of N exp. Clustering is clearly detected at low redshift:at1.5< z<2.4in the100km s?1bin,we measureξ=0.4± 0.1for lines with N H i>～1012.7cm?2.There is a hint of increasing amplitude with increasing column density: in the same redshift rangeξ=0.35±0.08for lines with N H i>～1012.5cm?2.The trend is not signi?cant but agrees with the behavior observed at higher redshifts(Cristiani et al.1997;Kim et al.1997).Unfortunately the number of lines observed in the interval1.5 allow us to extend the analysis to higher column densities, Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 15 Fig.12.Evolution of the two-point correlation function with redshift for Ly αlines with column densities above N H i =1012.7cm ?2.Short-dashed and long-dashed lines represent the 1σand 2σPoisson errors. although groups of strong lines are occasionally evident (e.g.the range 3230–3270?A in HE0515–4414). The amplitude of the correlation at 100km s ?1de-creases signi?cantly with increasing redshift from 0.4±0.1at 1.5 Voids along the three low-redshift lines of sight were searched for. For comparison with previous results (Car-swell &Rees 1987;Crotts 1987;Ostriker et al.1988),we identify a void as a region without any absorption stronger than N H i ～1013.5cm ?2over a comoving size of at least 30h ?1Mpc (assuming q 0=0.1). Figs.13–14show the voids detected in the spectrum of HE0515–4414and HE2217–2818,respectively.No signi?-cant void was found in the spectrum of J2233–606.The wavelength range used for searching for voids has been selected to be redward of the QSO’s Ly βemission line and 3000km s ?1blueward of the QSO’s Ly αemission to avoid the proximity e?ect.The wavelength range searched Fig.13.The spectrum of HE0515–4414with the void at z =1.570.See the text for the details. for voids is larger than that used to study the Ly αforest in other sections. Table 7lists the dimensions of the voids,as well as the probability of ?nding a void larger than their comoving size.The probability was calculated assuming a Poisson distribution of the local forest.In this case,the probability of ?nding a void larger than a given size x gap is P >(x gap )=1?(1?exp ?x gap )n ,where x gap is the line interval in the unit of the local mean line interval and n is the number of lines with N H i ≥1013.5cm ?2(Ostriker et al.1988).The joint probability of ?nding two voids with a size larger than 40h ?1Mpc at z ～2,as observed in the spectrum of HE2217–2818,is of the order of 2×10?4.The results correspond very well to the probability estimates derived from the simulations described above. There are di?erent ways to produce a void in the for-est:a large ?uctuation in the gas density of absorbers,en-hanced UV ionizing radiation from nearby faint QSOs or star-forming galaxies,feedback processes (including shock heating)from galaxy formation (Dobrzycki &Bechtold 1991;Heap et al.2000;Theuns et al.2000a).We recall here that the void B in the spectrum of HE2217–2818cor-responds to a region of above-average Doppler parameter (Sect.4.3.3).It will be interesting to carry out deep imag-ing around HE2217–2818to identify QSO candidates and investigate whether a local ionizing source is responsible for the ～50h ?1Mpc voids. 5.The ?ux statistics on the Ly αforest The traditional Voigt pro?le ?tting analysis is limited by two major drawbacks.First,there is no unique solution.Although the χ2minimization is normally applied to the ?t,di?erent ?tting programs produce slightly di?erent re-sults.Even using the same program,di?erent χ2thresh-olds lead to di?erent numbers of lines when line blending is severe.As the resolution and S/N increase,many for-est lines show various degrees of departure from the Voigt pro?le.This departure can be ?tted by adding physically improbable narrow components in high S/N data to im-prove the overall ?t,while the same pro?le can usually be 16Tae-Sun Kim,Stefano Cristiani&Sandro D’Odorico:The Lyαforest at1.5 HE0515–4414A3088–3161 1.5700.06061.1 5.70.045 HE2217–2818A3504–3579 1.9130.06254.38.40.012 HE2217–2818B3878–3946 2.2180.05643.58.00.018 Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 17 (Press et al.1993;Rauch et al.1997).We also remind the reader to be particularly cautious in using the line list of Q0302–003at z ～2.9,which is the only one not generated by VPFIT.As for the Voigt ?tting analysis,a systematic di?erence in N H i and b could change the results in this Sect.at z ～2.9. 5.1.The mean H i opacity The H i opacity,τH i (λ),is de?ned as τH i (λ)=?ln(F λ/F c ),where λis the observed wavelength,F λis the observed ?ux at λ,and F c is the continuum ?ux at λ.Since the opacity scales logarithmically,the mean opac-ity cannot be measured accurately when F λ≈0.The e?ective opacity,τe?,is typically used in place of τH i measures (in fact,the e?ec-tive optical depth τe?),together with other opacity mea-sures compiled from the literature.Filled circles are the τH i measurements)were measured including high-column-density regions in the spectra except damped Ly αsys-tems.The Press et al.measure (dotted line)was derived at low resolution,including damped Ly αsystems.Our experiments with the UVES data show that there is no noticeable di?erence between the τH i from the observed spectra.This indicates that very weak lines do not signi?cantly contribute to τH i from the spectra generated from the published line lists using high resolution,high S/N data can be con-sidered to be reliable.In Table 8,we list the estimated τH i .On the other hand, the local continuum ?tting generally adopted for high-resolution data may result in an underestimation of the continuum,i.e.an underestimated τH i (dotted line)from low-resolution data by Press et al.(1993)is higher than any other mea-surements.Small triangles from Zuo &Lu (1993)were estimated from the published line lists using intermediate resolution data,which usually do not include low column density lines.Thus,the Zuo &Lu estimates are about a factor of 2lower than the PRS formula at z ～3.Other Fig.15.The H i opacity as a function of (1+z ).Filled cir-cles represent the mean H i opacity from the UVES data.Small triangles and diamonds represent τcent H i uncorrected for continuum ?tting uncertainty since all other observations were not corrected for continuum ?tting uncertainties),respectively.Open circles,the star,the large square,the small diamond and the small square are estimated from the spectra generated arti?cially us-ing the line list provided by Hu et al.(1995),Kulkarni et al.(1996),Lu et al.(1996),Kirkman &Tytler (1997),and Outram et al.(1999a),https://www.wendangku.net/doc/c72793385.html,rge triangles were read from Schaye et al.(2000).All the x-axis er-ror bars represent the z range used for the τH i (z )=0.0037(1+z )3.46,given by the conventional power law ?t.The solid line represents the power law ?t to the UVES and the HIRES data. observations fall inbetween the PRS formula and the Zuo &Lu values. There is a scatter in 18 Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 Table 8.The mean H i opacity HE0515–4414 1.61 1.54–1.680.0860.049 ?0.051 This study Q1331+170 1.85 1.68–2.010.0640.049 ?0 .051 Kulkarni et al.(1996)Q1100–264 1.96 1.85–2.090.1120.023 0.017 Schaye et al.(2000) J2233–606 1.98 1.80–2.170.1610.049 ?0.051 This study J2233–606 2.04 1.92–2.170.1420.049 ?0.051 Outram et al.(1999a) HE2217–2818 2.13 1.92–2.330.1310.049 ?0.051 This study HS1946+7658 2.66 2.50–2.810.2340.049 ?0.051 Kirkman &Tytler (1997),HIRES Q0636+680 2.80 2.58–3.020.2980.049 ?0.051 Hu et al.(1995),HIRES Q0302–003 2.87 2.63–3.110.2750.049 ?0.051 Hu et al.(1995),HIRES Q0014+813 2.97 2.74–3.200.2890.049 ?0.051 Hu et al.(1995),HIRES Q0000–263 3.75 3.48–4.020.7330.049 ?0.051 Lu et al.(1996),HIRES Q2237–061 3.84 3.69–4.020.750.04 ?0.04 Schaye et al.(2000),HIRES Q2237–061 4.31 4.15–4.43 0.830.06 ?0.08 Schaye et al.(2000),HIRES τH i values from Hu et al. (1995)and from Kirkman &Tytler (1997)are a factor of 1.2lower than the Rauch et al.values.Since the line lists for the Rauch et al.QSO sample are not published,we cannot test whether the presence of high-column-density systems in their sample causes the higher τH i (z )=0.0030±0.0008(1+ z )3.43±0.17 .The new UVES data at 1.5 that τH i measures at z >4.5(cross and thick diamond)from the Keck II/LRIS data suggest that τH i .In fact, they correspond better to the Press et al.formula,which was also derived from low-resolution data.Without more high-resolution data at higher z ,it is premature to con-clude that the τH i ∝(1+z )3.3/ΓH i (z )(Machacek et al.2000).Although there are a few high-column-density systems in Fig.15, our result on τH i ∝(1+z )3.43±0.17at 1.5 5.2.The one-point function of the ?ux The one-point function of the ?ux (or the probability den-sity distribution function of the transmitted ?ux),P (F ),is simply the number of pixels which have a ?ux between F and F +dF for a given ?ux F over the entire number of pixels per dF .In other words,it is the probability density to ?nd a pixel at a given F (Miralda-Escud′e et al.1997;Rauch et al.1997;Bryan et al.1999;Machacek et al.2000;Theuns et al.2000b). Fig.16shows P (F )as a function of F .The one-point function of the ?ux at F <0and F >1from observations is due to observational and continuum ?tting uncertain-ties.The non-smooth P (F )at The ?attening towards F ～1at After smoothing P (F )at Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 19 Fig.16.The one-point function of the ?ux,P (F ),as a function of F at di?erent z .Strong absorption lines (smaller F )disappear more rapidly than weak absorption lines (larger F )as z decreases. ?tting analysis:the higher column density forest disap-pears more rapidly than the lower column density forest as z decreases. 5.3.The two-point function of the ?ux The two-point function of the ?ux,P (F 1,F 2,?v ),is the probability of two pixels with the ?v velocity separation having normalized ?uxes F 1and F 2.It is usually expressed as ?F (?v,δF 1)is the mean ?ux di?erence between two pixels with F 1and F 2,which are separated by ?v .At ?v >200km s ?1, ?F (?v,δF 1)con-tains information on the pro?le shape of absorption lines.However,great care has to be exercised in the interpreta-tion since ?F (?v,δF 1)as a function of ?v at dif-ferent z .The left-hand panel shows the results for the observed spectra at z <2.4and the spectra generated with noise at z >2.4,while the right-hand panel shows the results for the spectra generated from the line lists for all z without noise.There is no noticeable di?erence between the two panels.To be comparable with the sim-ulations by Machacek et al.(2000),the ?ux range was chosen to be ?0.1≤F ≤0.1,which corresponds to Fig.17.The mean ?ux di?erence, ?F (?v,δF 1)is an av-eraged quantity,it is not obvious to interpret ?F (?v,δF 1)is not clear. At ?v <30km s ?1 , ?F (?v,δF 1)is wider than at any other z .At ?v >30km s ?1,there is a tendency for the width of ?F (?v,δF 1)at which ?F (?v,δF 1)pro?le than a simulation with a lower gas temperature.However,numerical simulations also show that higher b values at higher z may be a result of other physical processes.Variations of 20 Tae-Sun Kim,Stefano Cristiani &Sandro D’Odorico:The Ly αforest at 1.5 , Fig.18.The line counts of the Ly αforest.The upper panel shows the normalized ?ux as a function of the ?lling factor.The lower panel represents the line counts from the observed spectra and the spectra generated with noise,which were smoothed with a 20km s ?1box-car function in order to decrease noise. mine than the conventional line counting from the pro?le ?tting. The upper panel of Fig.18shows the normalized ?ux of the observed spectra and the spectra generated with noise as a function of the ?lling factor.The ?lling fac-tor is the fraction of the spectrum occupied by the pixels whose normalized ?ux is smaller than a given F t .Since this method is sensitive to noise,the spectra were smoothed with a 20km s ?1box-car function.Except at Fig.19shows the line counts as a function of the ?ll-ing factor again.In this diagram,the line counts were calculated using the arti?cial spectra generated from the ?tted line lists for each QSO without adding noise,i.e. they have an in?nite S/N.Note that this process does not include weak lines,usually not present in the ?tted line lists.Unlike the lower panel of Fig.18,the curves de-scribing the line counts as a function of the ?lling factor show a similar progression as a function of z when a ?ll-ing factor is smaller than ～0.3,except for Since the ?lling factor is determined mainly by the Hubble expansion,the negligible z -dependence of the line counts suggests that the evolution of the forest at 1.5 Miralda-Escud′e et al.(1996)?rst introduced a correlation function using a pixel-by-pixel transmitted ?ux,which is more straightforward than the two-point velocity corre-lation function.Cen et al.(1998)developed this concept further.We analyzed the clustering properties of the Ly αforest,following Cen et al.’s methods (1998).Among their newly de?ned correlation functions,we only consider the step optical depth correlation.In general,the trends we found from the step optical depth correlation function hold for the other correlation functions. The step optical depth correlation function ξτ,s is de-?ned as ξτ,s (?v )≡ <τs (v +?v )τs (v ) > LED- 照明市场分化 目前LED照明市场大致可分为：商业照明/室内照明两大系列，商业照明与室内照明有有可以各自细分出不同种类的产品系列，常见如下： LED 室内照明 1. LED日光灯 2. LED射灯 3.台灯4丄ED壁灯5丄ED吊灯6丄ED吸顶 灯7.LED 天花灯8. 筒灯9.LED 灯泡等 LED商业照明 1. LED路灯 2.LED庭院灯3^LED隧道灯4^LED交通灯5丄ED水池灯6丄ED 草坪灯7. LED 洗墙灯8. 景观灯等 LED消费性可携式照明 1. LED手电筒2丄ED矿灯3丄ED潜水灯4.LED露营灯等 综合目前LED照明产业现况，比较适中小型企业进入LED照明领域的产品为：LED室内照明（如：LED日光灯射灯台灯壁灯吊灯吸顶灯球泡等），其原因为：技术门槛相对于商业照明来讲要求较低，资金投入较小，市场容量较大；回款及利益见效较快；而商业照明（如：LED路灯景观灯隧道灯交通灯庭院灯等）相对于LED照明来讲，其技术要求较高，不管是研发还是市场资金投入都很庞大，市场主要针对于政府工程及基础建设，回款较慢，同时利润及风险均较高，所以我认为商业照明比较适合资金雄厚的企业来进行投资；对于LED消费性可携式照明产品（如：LED矿灯潜水灯手电筒等）这部份产品已做了三年左 右，其技术与市场均已成熟，相对于室内照明及商业照明来讲，已经没有什么技术含量，市场也趋进于饱和状态，在做这方面的LED照明产品的投资时，需要重点考虑到回报短期效益回报问题。 商业照明市场分析 据台湾TEK 市场分析，全球照明市场到2011 年将成长至1320 亿美元，其中北美地区仍是全球用电量最多的区域，但欧美国家对于照明需求的成长将趋缓，包括中国及亚洲、非洲等新兴国家需求则将在新建设需求、电力普及推动、以及户外照明使用增加等动力带动下，快速成长；其中，照明灯市场规模254 亿美元，照明设备/ 装置的市场规模1066亿美元。商业照明占全球总照明市场用电量43%，比例最高，其中零售业、办公大楼、仓储用途、教育大楼、保健照护等应用领域用电量合计占总商业照明用市场70%。 目前LED照明在全球照明市场比例仍低，2007年全球LED照明市场规模约3.3亿美元，若与2006年相较，年成长率达60% LED照明市场发展最快的年度；2008年由于受到全球金融危机的影响，全球LED照明市场规模约为4 亿美元，也比2007 年增长21%左右。加上市场需求型态为少量多样, 因此仍属基础型市场；随着LED平均成本逐渐下降，加上产品校能不断提升，LED 照明商品化的速度也将加快进行。 其中，现阶段占LED照明最大的应用领域为建筑景观照明，占全球LED 照明市场比重达45%由于白光LED光通量和发光效率提升，包括路灯、交通灯、庭园灯、探照灯、阶梯灯、阳台灯等采用比率正快速成长，尤其以中国为最大应用市场，比重达36%。 商业照明目前主要集中在LED 路灯景观灯护栏管隧道灯矿灯后备照 LED照明产品标准化，韩国率先制定为哪般？ 韩国于2009年启动了LED照明产品标准化。 ·韩国提出了将韩国的LED产业提升至世界水平、领军市场的目标。 ·在2012年之前将向LED研发累计投资4万亿韩元。 LED照明在存在价格、可靠性等问题的同时，产业规模日益壮大。为了进一步推动LED照明的普及，壮大产业，包括安全标准、可靠性标准在内，LED照明的标准化开始推进。除市场发达的日美欧外，韩国、台湾等国家和地区也展开了类似的讨论。其中，韩国于2009年3月制定、实施了LED照明标准。 继韩国之后，台湾地区和中国大陆也开始制定标准，预计最快会在2010年内实施。现在，台湾的“经济部标准检验局”表示，CNS(China National Standars)正在为35种LED制定相关标准，其中12项LED照明标准已审议完毕。中国工业和信息化部半导体照明技术标准工作组已经基本完成了7项LED照明标准的制定工作。日本政府和多个工业协会虽然也在讨论制定标准，但还未到达制定状态，目前仍在审议之中。由此日本等LED发达国家虽然积极探讨制定LED照明标准，但最终却是落后于韩国的局面。 韩国制定的标准内容是什么?为什么韩国先行完成了标准化?通过对以上问题的调查，我们看到了韩国快速捕捉商机的姿态。 KS认证标准的一部分与LED照明有关 在韩国，LED照明产品要符合的认证标准是“KS认证标准”(图1)1)。准确地说，LED照明产品认证标准是KS认证标准的一部分。KS认证标准原本由韩国知识经济部技术标准院于1963年导入，此次制定的标准通过部分修改，增加了关于LED照明的部分。2009年其实是KS认证标准时隔46年来的首次修改。 LED照明产品及解决方案比较 本方案包含LED恒流驱动电源，电路采用单串或并联方式连接，电源效率高达93%以上，功率因素90%以上，与其它方案比较该方案效率更高、成本更低。散热部分，我们采用新型的导热材料取代传统的铝基板，大幅度提高产品的散热效果，降低光衰、确保LED灯具更加稳定。同时我们还提供灯具呼吸系统，保证灯具内外气体自由交换。光源部分我们能提供光效60--100LM/W，色温：2800-7000K 范围的全系列产品，产品广泛应用于路灯、隧道灯、射灯、筒灯、手电筒等。 提供TotalSolution目的如下： 提供客户完整解决方案 提供最有竞争力的BOMCost 提供技术支持 方案介绍： 一、LEDDriver：NXP、Richtek、Infineon、Microchip A、LED路灯解决方案（智能方案）：NXP+MICROCHIP 目前我们已经使用TEA1750(NXP)+DSPIC30F2020(Microchip)用来实现多路LED路灯、隧道灯驱动方案。全智能控制多路LED路灯解决方案，可根据周围环境需要，自动控制光照亮度，每路可单独控制调光。可以实现温度传感、Usart通信、日光感应调光、按键输入等功能。 调光的原理是通过调节PWM占空比调节输出电流大小，全软件实现无级调光。 该方案能确保每路电流均衡，只需一颗IC，与同类多路恒流方案比较，成本更低。 DEMO(图片)： B、LED路灯解决方案（一级转换）：Infineon+NXP 我们采用IFXIC实现单极PFC方案，驱动单串LED。相比其它方案比较，该方案电源转换效率更高，整体成本更便宜。同时为保证单串LED电路稳定性，提供LED保护电路，当单颗或多颗LED灯损坏时（断路），其它LED灯不受影响，最大程度的减小了坏灯对整体电路的影响。 产品选型表： 产品外观图： C、LED路灯解决方案（二级转换）：RICHTECK 我们采用NXPIC实现AC-DC的恒压转换，二级转换采用RICHTECK恒流IC实现恒流0.35A-1.5A 输出。该方案能输出60V高压，1.5A大电流，整体成本更便宜。同时RT8450具备两种调光方式，满足多种调光需求。1、通过调整LED中流过的电流大小来调整光输出量。其优点是：输出是稳定的，遇到EMI问题的几率较低。其缺点是：当LED中流过的电流不同时，其光输出的色度会发生变化。2、通过调整LED中流过恒定电流的时间比例来调整光输出量。其优缺点和方法1刚好相反。 二、LED散热方案（石墨材料） 我们使用石墨材料取代传统的铝基板散热，该材料导热系数是铝板的两倍，不同于铜、铝等金属球体导热方式，采用水平导热方式，有效的保证产品均热性。 外观图： 常见led产品 一、Led照明产品..................................................... 1 LED景观照明 ........................................................................................................................ 1.1LED?射灯/灯杯 ............................................................................................................ 1.2LED投光灯 .................................................................................................................. 1.3LED发光地砖 .............................................................................................................. 1.4led星星灯串 ................................................................................................................. 1.5LED灯带、彩虹管 ...................................................................................................... 1.6LED水底灯 .................................................................................................................. 1.7LED洗墙灯 .................................................................................................................. 1.8 大功率LED路灯 ....................................................................................................... 1.9LED大功率球泡灯 ...................................................................................................... 1.10LED轮廓灯 ................................................................................................................ 1.11 LED地埋灯................................................................................................................ 1.12LED幕墙灯 ................................................................................................................ 1.13LED草坪灯 ................................................................................................................ 2 led室内照明 ........................................................................................................................... 2.1 LED台灯 .................................................................................................................. 2.2 LED壁灯 .................................................................................................................. 2.3 LED吸顶灯 .............................................................................................................. 2.4 LED日光灯 .............................................................................................................. 3 led特种照明 ........................................................................................................................... 3.1 LED充电手电筒 ...................................................................................................... 3.2 LED矿灯 .................................................................................................................. 二 LED显示屏产品.................................................... 1、常规LED显示屏 ................................................................................................................ 2、特殊LED显示屏 ................................................................................................................ 2.1 LED彩幕 .................................................................................................................. 2.2 LED日月光板 .......................................................................................................... 三 led交通灯产品.................................................... 1.1太阳能爆闪灯 .............................................................................................................. 1.2高速公路可变情报板 .................................................................................................. 四 Led发光字产品.................................................... 1.1led动感灯箱 ................................................................................................................. 1.2发光字LED模块 ........................................................................................................ 在中国的照明灯具行业中，最新排行榜中照明灯具十大品牌排行如下,排名不分先后： 1、雷士照明(惠州雷士光电科技有限公司) 惠州雷士光电科技有限公司，是一家专业照明电器与电气装置产品制造商。位于广东惠州汝湖镇雷士工业园。凭借优异的产品品质、卓越的服务精神，赢得了客户的广泛认可与赞誉,雷士在国内商业照明领域一直保持行业领先地位，其“NVC雷士照明”品牌已成为国内照明行业领袖品牌。多年来，雷士已获”中国驰名商标”、“国家免检产品”、“广东省著名商标”、“广东省名牌产品”等多项殊荣。 雷士产品涵盖：商业照明、家居照明、户外照明、智能照明、雷士电工和光源电器等六大种类六十余个系列数千个品种，为客户提供了全方位的照明与电气装置项目的产品配套、客户服务和技术支持。公司自1999年成立以来，销售业绩保持高速增长，雷士的高速成长引起了企业界的高度重视，雷士于2005年先后入选了2005年中国企业“未来之星—最具成长型的新兴企业”和“2005年中国成长企业100强”。2006年2月，占地20万平方米的雷士工业园竣工投入使用。为加快国内生产基地战略布局。目前投资数亿的重庆万州雷士工业园已于2007年3月18日竣工投产。 2、欧普照明(中山市欧普照明股份有限公司) 欧普照明是中山市欧普照明股份有限公司旗下主打产品之一，在照明业已成为公认的知名品牌，所在公司成立于1996年8月，是一个创新型快速发展的公司，一贯重视科学研究、技术开发及人才培养。欧普照明的产品涵盖家居，商照，电工，光源等领域，是集研发、生产和销售于一体的综合性照明企业。目前有28个办事处和遍布全国1300多家专卖店，5000多家销售网点，产品远销世界十几个国家和地区。 欧普照明的产品涵盖家居照明、工程照明及电工产品等领域，家居照明产品有吸顶灯、节射灯、筒灯、天花射灯、壁灯、餐厅灯、感应灯、镜前灯、护眼台灯、T5支架、浴霸；商业照明产品有：光源、电器部分、天花灯、低压射灯、大功率射灯、格栅射灯、筒灯、灯盘、支架、金卤灯等产品，为家居照明、商业照明、电工产品的系统集成商。目前有31个分公司/办事处和遍布全国1000多家专卖店，5000多家销售网点，产品远销世界十几个国家和地。 欧普照明已成为照明业内公认的名牌，2002年荣获“广东省著名商标”和“广东省名牌产品”，同年荣获“国家免检产品”；2004年入选中国500最具价值品牌；还获得了国家3C认证、节能认证等国家权威认证,同时获得欧盟CE、德国莱茵实验室ISO9001等国际权威认证,公司还拥有先进的检测设备，严格的质量控制和检测，为海内外消费者提供优质的照明产品. 2004年，在迪拜成立首家海外分公司，参与国际化竞争，为谋求全球化经营奠定了基础。欧普照明将专注于创造光的价值，以强大的技术开发能力和产能为基础，以为消费者提供优质的光源、电子件、灯具和最佳的照明解决方案为品牌使命，与中国照明业一起发展、共同繁荣。 3、TCL照明(TCL集团股份有限公司) TCL照明电器（武汉）有限公司的前身是成立于2000年的惠州TCL照明电器有限公司，是TCL集团进军照明领域的核心企业，专门从事照明产品的研发、生产与销售，2009年公司迁至武汉。公司旗下产品涵盖工程照明、家居照明、光源电器、工业照明、集成吊顶和浴霸等，近30个产品系列。照明以科技为依托，以节能为重点，十分注重产品创新和技术创新，积极开展与国内高校和国外专业机构的技术合作，紧跟世界照明电器发展潮流，并 LED照明产品质量现状及分析 自科技部启动“十城万盏”半导体照明工程以来，重庆市作为首批21个试点城市之一，采取了积极稳妥的先试点再推广、先探索试点再规模试点的方针，逐步分阶段地推动重庆半导体照明的发展。 根据重庆市的试点方案，试点工作包括了室外照明、室内照明和特种照明三大领域，囊括几乎所有的日常照明场所，涉及的照明灯具也多种多样。为及时掌握这些照明灯具的质量特性水平，在市科委的支持下，重庆市依托重庆大学光电工程学院，设立了重庆市LED照明研发与产业联盟的公共性光学设计与检测服务平台??“重庆大学LED光学设计与检测中心”，针对LED应用领域的共性关键技术与应用问题，为企业进行LED灯具的质量检测、改进优化与验证测试，进行室内照明、道路照明、隧道照明等应用配光设计及照明效果验证。自2009年11月至2010年6月间已完成对重庆、上海、浙江、广东、西安、大连等省市36家企业15种共100款灯具产品的测试，为“十城万盏”工程建立了产品目录库，为试点工程的效果建立了对比数据库。本文就此期间送检灯具产品的质量状况进行汇总及分析，以便同行参考。 一、灯具质量水平 1. 送检灯具分布情况 图1 灯具分类图 本次所测灯具大部分是为配合“十城万盏”工程的送检灯具，也有少部分来自企业非工程所需的送检。图1按灯具所属的照明领域进行了分类，可见室外照明产品占据了送检灯具的大多数，达61%。虽然国家、重庆市“十城万盏”工程的初衷是功能照明，但还是被片面地误解为道路照明，形成“百城千厂齐上道路照明”的形势。由于重庆山城独特的地貌特征，隧道灯在室外照明灯具中的比重达三成以上。 送检产品中室内照明灯具共30盏，包括日光灯、球泡灯、天花灯等，占送检灯具总数的三成。虽然室内照明灯具在数量上只有室外照明灯具的一半，远少于室外照明灯具，但与全国的形势相比还是要均衡得多。由于日光灯和球泡灯的使用更符合人们的用灯习惯，而且节约安装成本，这两类灯具的送检数量占室内照明灯具的三分之二。 2. 灯具光效水平 附件三： 半导体照明产品技术要求（2010版） 目 录 一、名词解释 (1) （一）LED照明产品 (1) （二）规格 (1) （三）额定值 (1) （四）初始值 (1) （五）光束角和中心光强 (2) （六）光通维持率 (2) （七）显色指数维持 (2) （八）平均寿命和额定寿命 (2) 二、适用范围及指标规定 (3) （一）反射型自镇流LED照明产品 (3) （二）LED筒灯 (5) （三）LED道路/隧道照明产品 (7) 三、试验方法 (8) （一）安全要求测试 (8) （二）电磁兼容测试 (8) （三）光电性能测试 (9) 四、参考和引用标准 (10) 附表 ：LED照明产品中心光强最低要求（cd） (11) 一、名词解释1 （一）LED照明产品 1.反射型自镇流LED灯 类似于MR16、PAR20、PAR30和PAR38的，含有LED光源和保持其稳定燃点所必需的元件并使之成为一体的，灯头符合GU10、B22、E14或E27的LED 灯，这种灯在不损坏其结构时是不可拆卸的。 2.LED筒灯 LED光源和保持其启动和稳定燃点所需元件一体化的，或驱动装置分离式的，LED下射灯。 3.LED道路/隧道照明产品 满足道路/隧道照明要求的组合式LED照明装置，除了发光二极管(LED)作为光源发光外，还包括其他部件，例如光学、机械、电气和电子部件，并将这些部件组合成一个整体。 注：所指LED道路照明产品其驱动控制装置可为分离式结构。 （二）规格 根据产品类型不同对LED照明产品作不同的规格划分。 其中，反射型自镇流LED照明产品划分为MR16、PAR20、PAR30和PAR38四种规格；LED道路/隧道照明产品以额定光通量划分为3000lm、5400lm、9000lm和14000lm四种规格。 （三）额定值 额定工作条件下上述LED照明产品的参数值，该值由产品生产商或责任销售商指定，包括额定光通量、额定相关色温和额定功率等参数。 （四）初始值 为使新出厂的LED照明产品达到性能稳定以进行评估，对产品进行规定小时数的老炼并在产品达到稳定工作时所测得的参数值称为产品的初始值，初始值用于评价LED照明产品的初始性能，包括初始光通量、初始光效、初始相关色温、初始显色指数等参数。 1此处名词解释针对本规则进行规定 LED照明产品国内外标准分类简介 LED照明产品具有寿命长、高能效、可靠性高以及低污染等方面特点，这几年发展迅速，产品市场增长很快。LED照明产品技术发展也非常快，各种各类的新型LED照明产品最近几年市场中也层出不穷。为了适应各种LED照明新产品的评价要求，相关的检测及评价技术标准或技术规范也迅速发展，最近新颁布的国际标准、国家标准及行业或地方标准或技术规范数量也较多，同时还有一部分LED照明产品国内外标准目前正在制定和完善过程中。 文章对各种LED照明产品的国内外标准或技术规范进行分类、梳理和分析综述，以帮助LED照明行业从业人员对LED照明产品的标准框架和技术规范有一个总体的了解。 1.LED照明产品标准分类简介 LED照明产品按照产品类型分类，可以分为LED灯具产品、LED用控制器产品、LED 光源产品及LED连接器产品等类型；LED照明产品按照标准内容分类，可以分为安全领域标准、性能领域标准、能效领域标准及电磁兼容领域标准等标准；LED照明产品按照标准发布来源分类，可以分为国际标准、欧盟标准、国家标准及我国的行业或地方标准或技术规范，具体分类详见下图。 2.LED灯具产品标准介绍 2.1LED灯具产品安全标准 (1)LED灯具产品安全的国际标准 目前，已有的灯具安全国际标准系列，IEC60598系列，适用于LED灯具。IEC60598系列标准目前已经发布共22个标准，分为IEC60598-1：灯具第1部分一般要求与试验，和IEC60598-2系列：具体灯具产品标准系列。具体标准详见表1灯具安全标准汇总表。 由于LED亮度高，光束角窄，LED的光辐射会对人体造成危害，LED对人体的危害主要是对人的眼睛和皮肤的危害；特别近年的高功率LED推出后，LED的光辐射对人体危害的防护越来越引起人们的重视。LED灯具的光生物安全要求和评价，适用IEC62471，灯和灯系统的光生物安全性标准，以及LED灯具的激光安全要求，适用IEC60825-1，激光安全性标准。在之前的CTL决议(SheetNO.：005/05，SheetNO.：005/06.m，SheetNO.：005/07)中，评价LED灯具的光生物安全要求时，引用IEC60825-1，在最新的CTL决议(SheetNO.：DSH0744，SheetNO.：DSH0748)中，评价LED灯具的光生物安全要求时，引用IEC62471，具体标准详见表2光生物安全标准汇总表。 (2)LED灯具产品安全的欧盟标准 灯具安全欧盟标准系列，EN60598系列，对应于IEC60598系列标准。灯和灯系统的光生物安全性标准，EN62471，以及激光安全性标准，EN60825-1，分别对应于IEC62471和IEC60825-1.具体标准详见表1灯具安全标准汇总表和表2光生物安全标准汇总表。 (3)LED灯具产品安全的部分国家标准 1)我国的LED灯具安全标准 我国的灯具安全标准系列包括GB7000系列，等同采用国际IEC60598系列标准；另外，我国还编写有GB24461洁净室用灯具技术要求。灯和灯系统的光生物安全性标准，GB20145，以及激光安全性标准，GB7247.1，分别对应于IEC62471和IEC60825-1.具体标准详见表1灯具安全标准汇总表和表2光生物安全标准汇总表。 LED照明灯具十大品牌最新排行 时间：2013-01-23 14:55:03 来源：陶瓷中国作者：朱力 在中国的LED照明灯具行业中，最新排行榜中LED照明灯具十大品牌排行如下,排名不分先后： 雷士照明 雷士照明是照明灯具-节能灯十大品牌，中国500最具价值品牌，商业照明行业领先企业，专业照明企业之一。 雷士是绿色照明的倡导者，“光芒行动”则是雷士推广节能型照明产品、传播照明节能文化的实践。依托具有行业领先水准的研发中心和大型节能灯、电子镇流器生产基地，向市场推出“光芒”系列节能灯饰和电子镇流器产品，以行动支持中国乃至世界的节能环保事业。 欧普照明 欧普照明是中山市欧普照明股份有限公司旗下主打产品之一，在照明业已成为公认的知名品牌，所在公司成立于1996年8月，是一个创新型快速发展的公司，一贯重视科学研究、技术开发及人才培养。欧普照明的产品涵盖家居，商照，电工，光源等领域，是集研发、生产和销售于一体的综合性照明企业。目前有28个办事处和遍布全国1300多家专卖店，5000多家销售网点，产品远销世界十几个国家和地区。 TCL照明 TCL照明电器(武汉)有限公司的前身是成立于2000年的惠州TCL照明电器有限公司，是TCL集团进军照明领域的核心企业，专门从事照明产品的研发、生产与销售，2009年公司迁至武汉。公司旗下产品涵盖工程照明、家居照明、光源电器、工业照明、集成吊顶和浴霸等，近30个产品系列。照明以科技为依托，以节能为重点，十分注重产品创新和技术创新，积极开展与国内高校和国外专业机构的技术合作，紧跟世界照明电器发展潮流，并于2005年1月建成了华南第一个国家级照明试验室。凭借过硬的产品质量及品牌影响力，TCL照明夺得众多荣誉称号。 飞利浦照明 飞利浦照明是照明灯具十大品牌，中国驰名商标，创立于1891年，全球最具价值品牌之一，全球照明领域领先的制造商。 由于照明用电占了全球电力总耗的19%，因此，高效节能照明的使用将大大地减少全球能源消耗，并降低有害的二氧化碳排放。飞利浦为所有领域提供先进的高效节能照明解决方案，包括：道路、办公室、工业、娱乐和家居照明等。凭借激动人心的新型照明技术和应用(例如LED技术)，飞利浦也是引领行业发展的先锋。除了高效节能外，飞利浦还不断提供诸多具有更多优越性的革命性照明解决方案。 三雄极光照明 创立于1991年的三雄极光，一直致力于开发和生产高品质、高档次的绿色节能照明产品。从第一款电子镇流器的研发到高效节能产品的全系列开发;从传统的产品制造者到提供照明整体解决方案的服务者，三雄极光一直致力于打造行业的领导品牌。期间开发研制了户内、户外、装饰类照明与电工四大品类，包含了各种台灯、光源、电工与电气配件共计两千多个品种。 松下照明 家电-电器十大品牌，中国十大电视-数码相机品牌，世界500强，日本著名品牌，中国 基本的色度测量 光通量： 光源每秒种发出的可见光量之和，简单说就是发光量。单位：流明（lm） 照度： 单位面积内入射的光通量，也就是光通量除以面积所得到的值。单位：勒克司（lux）。照度分为水平照度和垂直照度。水平照度为光通量入射水平表面的照度，垂直照度为光通量入射到垂直面的照度。 光强： 符号I，单位坎德拉cd，说明发光体在特定方向单位立体角内所发射的光通量 亮度： 符号L，单位尼脱cd/m2，说明发光体在特定方向单位立体角单位面积内的光通量 光效： 单位每瓦流明Lm/w，说明电光源将电能转化为光的能力，以发出的光通量除以耗电量来表示 平均寿命： 单位小时，说明指一批灯泡至百分之五十的数量损坏时的小时数 经济寿命： 单位小时，说明在同时考虑灯泡的损坏以及光束输出衰减的状况下，其综合光束输出减至一特定的小时数。此比例用于室外的光源为百分之七十，用于室内的光源如日光灯则为百分之八十。 色温： 以绝对温度K来表示，即将一标准黑体加热，温度升高到一定程度时颜色开始由深红-浅红-橙黄-白-蓝，逐渐改变，某光源与黑体的颜色相同时，我们将黑体当时的绝对温度称为该光源之色温。 因相关色温度事实上是以黑体辐射接近光源光色时，对该光源光色表现的评价值，并非一种精确的颜色对比，故具相同色温值的二光源，可能在光色外观上仍有些许差异。仅冯色温无法了解光源对物体的显色能力，或在该光源下物体颜色的再现如何。 不同光源环境的相关色温度 光源色温 北方晴空 8000-8500k 阴天 6500-7500k 夏日正午阳光 5500k 金属卤化物灯 4000-4600k 下午日光 4000k 冷色营光灯 4000-5000k 高压汞灯 3450-3750k 暖色营光灯 2500-3000k 卤素灯 3000k 钨丝灯 2700k 高压钠灯 1950-2250k 蜡烛光 2000k 光源色温不同，光色也不同： 色温在3300K以下，光色偏红给以温暖的感觉；有稳重的气氛，温暖的感觉； 色温在3000--6000K为中间，人在此色调下无特别明显的视觉心理效果，有爽快的感觉；故称为"中性"色温。 色温超过6000K，光色偏蓝，给人以清冷的感觉， a. 色温与亮度高色温光源照射下，如亮度不高则给人们有一种阴气的气氛；低色温光源照射下，亮度过高会给人们有一种闷热感觉。 b. 光色的对比在同一空间使用两种光色差很大的光源，其对比将会出现层次效果，光色对比大时，在获得亮度层次的同时，又可获得光色的层次。 采用低色温光源照射，能使红色更鲜艳； 采用中色温光源照射，使蓝色具有清凉感；LED灯产品分类及其基础知识
LED照明产品标准化
LED照明产品及解决方案比较
常见LED产品列表
LED照明厂家
LED照明产品质量现状及分析
半导体照明产品技术要求
LED照明产品国内外标准分类简介
LED照明灯具十大品牌最新排行
LED照明产品基本参数