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The Evolution of the Mass-Size relation to z = 3.5 in the GOODS-North Field Draft version November 12, 2010 Moein Mosleh Preprint typeset using LATEX style emulateapj v. 5/25/10 THE EVOLUTION OF THE MASS-SIZE RELATION TO Z=3.5 FOR UV-BRIGHT GALAXIES AND SUB-MM GALAXIES IN THE GOODS-NORTH FIELD Moein Mosleh1 , Rik J. Williams 2 , Marijn Franx 1 , Mariska Kriek3 Draft version November 12, 2010 Abstract We study the evolution of the size - stellar mass relation for a large spectroscopic sample of galaxies in the GOODs North field up to z ∼ 3.5. The sizes of the galaxies are measured from Ks -band images (corresponding to rest-frame optical/NIR) from the Subaru 8m telescope. We reproduce earlier results based on photometric redshifts that the sizes of galaxies at a given mass evolve with redshift. Specifically, we compare sizes of UV-bright galaxies at a range of redshifts: Lyman break galaxies (LBGs) selected through the U-drop technique (z ∼ 2.5 − 3.5), BM/BX galaxies at z ∼ 1.5 − 2.5, and GALEX LBGs at low redshift (z ∼ 0.6 − 1.5). The median sizes of these UV-bright galaxies evolve as Introduction ! Galaxies at high redshift have significantly smaller sizes than the local galaxies of similar masses ! Quiescent Galaxies are significantly smaller than star-forming galaxies of similar masses ! These studies are almost bases on Photometric redshift especially at high z ! Size measurements of Sub-mm or LBG galaxies at high z are also rare Williams et al. 2010 m Λ 0 2. DESCRIPTION OF DATA The sample of galaxies used here is based on the most Using most complete spectroscopic catalog of galaxies in mplete spectroscopic catalog of galaxies in the GOODS the GOODS-North Field. (Barger et al. 2008) eat Observatories Origin Deep Survey (Giavalisco Using U bandfield (Capak et al. 2004)Barger et al. (2008). This catl. 2004)) "North by g gives a compilation ofF606W all(V), spectroscopic observations " ACS Magnitudes (F435w (B), F775W (I), F850LP (Z) ) ried out in this field (e.g. Cowie et al. 2004; Reddy " Ks-band magnitudes from WIRCam (CFHT, 3.6 m) (6909) al. 2006; Wirth et al. 2004; Cohen 2001; Cohen et al. " NUV – FUV from GALEX (1016) 0), where each galaxy sample was selected in a differRedshift Distribution way. In addition, Barger et al. (2008) performed specscopic observations for certain subsamples. The cataincludes 2907 sources including stars and is restricted ources with Ks,AB < 24.5 or F 850LPAB < 26. There galaxies this large and faint have not been seen at any redshift. 3. SIZES The random uncertainties increase with size in all mag20 mag (top panel) nitude bins.✓ ForUsing objects with KAB GALFIT (Peng et al. 2002) to fit ≤ Sersic models the random✓ uncertainties in 8Msize recovery are < 5%. Ks-band image from Subaru Telescope FWHM ~ 0.5”with 21 < KAB < 22 the increasHowever, for ✓ galaxies Pixel scale = 0.12 arcsec/pixel ✓ uncertainties ing of random with sizes is significant. The increase in random uncertainties at larger sizes could be due to decreasing of surface brightness. However, since we are mainly concerned about the overall sample properties, the lack of systematic errors is more important. 4. STELLAR MASS ESTIMATES The stellar masses of galaxies were measured with the FAST (Fitting and Assessment of Synthetic Templates code) (Kriek et al. Fitting and✓Using Assessment of Synthetic Templates(FAST) 2009) code (Kriek✓Using et Salpeter al. 2009b). All fluxes from Barger et al. IMF & Solar Metallicity (2008) including four optical bands from ACS, the Ks ✓Masses are corrected by a factor of -0.2 dex (for consistency with a Kroupa (2001) IMF) infrared and U band were used to find the best-fit galaxy template SED toB, V the , I, Z, Ks broadband photometry using a ✓Bands: U, χ2 minimization procedure. Bruzual & Charlot (2003) Simulations Running simulation for testing the accuracy of parameter measurements Evolution of the mass size relation to z = 3.5 in the GOODS North field 3 Fig. 1.— Left panel : The points are the median of the relative difference between the recovered and input sizes versus magnitude based on our simulations. Right panel : The same comparison but for the relative difference between output and input Sérsic index. The error bars illustrate the 68% scatter. The random uncertainties of recovered sizes and Sérsic index increase with magnitude. 4 Mosleh et al. TABLE 1 Sub-samples Sample GALEX/LBG BM/BX LBG SMG sBzK Redshift 0.6 < z < 1.4 1.4 < z < 2.7 2.7 < z < 3.5 0.5 < z < 3. 1.4 < z < 3.2 log(M∗ /M" ) 8.8 - 11.0 9.8 - 10.8 10.2 - 10.8 10.0 - 11.7 9.8 - 11.7 Simulations No. of Sources 105 41 5 14 70 Samples of star-forming galaxies studied in this paper. lected from Steidel et al. (2003, 2004). For this paper, 41 BM/BX galaxies to KAB = 23 are selected from their sample with spectroscopic redshift z > 1.4. Galaxies analogous to the LBGs at 0.6 ≤ z ≤ 1.4 (hereafter GALEX/LBGs) are selected with the GALEX/HST (F U V − N U V )AB versus (N U V − F 435W )AB color-color diagram. Following the selection criteria used in Barger et al. (2008) and requiring z > 0.6, we include 105 GALEX/LBGs with KAB ≤ 23. In addition to the UV-bright galaxies in GOODS-N field, we also study sizes of the Sub-millimetre galaxies (SMGs) as a population of star forming galaxies at high redshifts. The subsample of SMGs for our studies is drawn from Chapman et al. (2005) and Pope et al. (2006). The catalog of SMGs provided by Pope et al. (2006) contains 35 candidates from GOODS-N field with 21 secure optical counterparts. Of these, only 8 galaxies in our observed images have spectroscopic redshifts. We further include 6 SMGs from the Chapman et al. (2005) HDF-North study. Therefore, our final SMG sample studied here contains 14 sources spanning 0.5 ≤ z ≤ 3. Besides these two populations, star forming galaxies at z > 1.4 can also be identified using BzK technique (Daddi et al. 2004). This technique is designed to cull galaxies from K-selected samples. Star forming BzK galaxies (sBzK ) tend to be more massive and have higher reddening than UV-selected galaxies. With this method, 70 sBzK galaxies at z > 1.4 and KAB ≤ 23 are selected 5. SUB-SAMPLES # UV- Bright Galaxies : e ability to identify and study distant galaxies h ๏ Lyman Break Galaxies (LBGs) ( 2.7 < z < 3.4 ) ved dramatically during the last two decades. Va election criteria < z < 2.7) been designed to select hig ๏ BM/BX (1.4have Selected from Reddy et al. 2006 Selected from Reddy et al. 2006 Catalog ๏ GALEX/LBGs (0.6 < z < 1.4) Selected by using (FUV-NUV) versus (NUV-F435W ) color- color diagram # Sub-mm Galaxies (SMG) Selected from samples of Chapman et al. 2005 & Pope et al. 2006 # Mosleh BzK et al. (sBzK) (1.4 < z < 3.2) Star-forming TABLE 1 Sub-samples Sample GALEX/LBG BM/BX LBG SMG sBzK Redshift 0.6 < z < 1.4 1.4 < z < 2.7 2.7 < z < 3.5 0.5 < z < 3. 1.4 < z < 3.2 log(M∗ /M" ) 8.8 - 11.0 9.8 - 10.8 10.2 - 10.8 10.0 - 11.7 9.8 - 11.7 No. of Sources 105 41 5 14 70 Samples of star-forming galaxies studied in this paper. 6. RESULTS 6.1. Size Evolution Evolution of the mass size relation to z = 3.5 in the GOODS North field Fig. 8.— Left panel : The correlation between color (V606 − z850 ) and surface density for galaxies in the redshift range of 0.5 < z < 1.5 and stellar masses 1010 < M/M! < 1011 in GOODS-N field. The blue stars are GALEX (LBGs) from GOODS-N and the brown circles are from CDFS. The gray symbols are all galaxies from CDFS and the black triangles are galaxies from GOODS-N. The plots indicates that blue galaxies having lower surface density. Right panel : The color (z850 − K) versus surface density for galaxies at 1.5 < z < 2.5, as the green squares are the BM/BX galaxies from GOODS-N and the brown circles are pseudo BM/BX from CDF-S. like, one would expect galaxies with AG Figure 3 we show the size distributions for UV have smaller half-light radii. Their “norm optical sizes are thus perhaps not strong galaxies between 10 < log(M < 11. Th ∗ /Mdue " )to possible Nonetheless, effects on the estimates, X-ray detected galaxies should istogram shows the measured half-light radii o low-confidence points. 6.2. Stellar Mass-Size X/LBGs at z ∼ 1 while the distribution of Relatio size We now investigate how mass-size distr galaxies compares to other g red for BM/BX galaxies (z UV-bright ∼ 2) are shown as tions. We further check if the relation b mass and size ofplot these galaxies existsUV to h histogram. It can be seen from this that The stellar mass-size distributions of ou in Figure 5. We have divided our sam galaxies at z ∼ 2 are smallershown compared to simila redshift bins, 0.5 < z < 1.5, 1.5 < z < 2.5, UV-bright galaxies are color coded the sam es at z ∼ 1. Specifically, the median half ligh Solid and dotted lines in each panel show relation from Shen et al. (2003) for star fo f BM/BX galaxies in this mass rangegalaxies is 2.68 0.1 and early-type at z ∼ 0,± respectiv symbols are the K -selected sample of gal Sizes of UV-Bright galaxies evolve by a median factor ofeffective 0.60±0.08 gnificantly smaller than the median (Fran South with stellar masses > 10 M rad between z ~2 to z~1 Comparing our results with the galaxies fr LEX/LBGs (4.42 ± 0.52 kpc). lows us toThis see where means our galaxies lie tha relati mass-selected sample. Brown solid lines TABLE 3 Median sizes of different samples Sample GALEX/LBG BM/BX LBG CDFS CDFS CDFS Quiescent(CDFS) Quiescent(CDFS) Quiescent(VD08) SMG Redshift 0.6 < z < 1.4 1.4 < z < 2.7 2.7 < z < 3.5 0.5 < z < 1.5 1.5 < z < 2.5 2.5 < z < 3.5 0.5 < z < 1.5 1.5 < z < 2 2 < z < 2.5 0.5 < z < 3. Size 4.42 ± 0.52 2.68 ± 0.19 2.22 ± 0.61 2.33 ± 0.1 2.40 ± 0.13 1.73 ± 0.18 1.32 ± 0.07 1.12 ± 0.32 0.9 ± 0.21 2.90 ± 0.45 median(log(M∗ /M! ) 10.2 ± 0.3 10.4 ± 0.2 10.6 ± 0.2 10.4 ± 0.3 10.4 ± 0.3 10.4 ± 0.3 10.5 ± 0.3 10.7 ± 0.2 11.23 10.8 ± 0.5 Notes. The median sizes of samples are for galaxies with stellar masses between 1010 − 1011 M! except for the quiescent(VD08) (van Dokkum et al. 2008b) and SMG galaxies. The CDFS sample is all galaxies at the same stellar mass range in CDF-S field. for galaxies in our sample. We have confirmed that there is a relation between stellar mass and size for UV-bright galaxies at 0.5 < z < 3.5. The relations are consistent for both spectroscopic and photometric redshift samples. Our results verify that there is no significant evolution of the slope of the size-mass relation to redshift ∼ 3.5. Fig. 3.— distribution of UV-bright galaxies with Fig.Size 9.— Top panel: Histograms show the distribution of sizes of stellar The evolution of the relation from z = 1 to z = 0 is galaxies (solid andat BM/BX (dotted lines). mass 10 Submm < log(M < 11 z ∼ galaxies 1 (blue histogram) and ∗ /M " ) line) not well established, as it is not straight forward to9.8 seThe gray region indicates apparent effective radii below 0.1”(∼ 1 " ∼ 2 (green histogram). The half light radii of UV-bright galaxlect Lyman Break galaxies at z ∼ 0. Some authors find kpc at z ∼ 2) which size measurements have large uncertainties. es (GALEX(LBGs)) at z ∼ 1distribution are larger than for BM/BX galaxiesevolution at Lower panel: Cumulative function SMGs (pink (e.g. Franx et al. 2008; Williams et al. 2010) ∼ 2. dimonds) and BM/BX galaxies (green squares). As the plot shows, in the stellar mass-size relation, however, Barden et al. the distributions of half-light radii of these two populations are (2005) have reported that the stellar mass-size relation comparable with SMGs being slightly larger. for disk galaxies remains constant from z ∼ 1 to the 6 Mosleh et al. 6.1. Size Evolution Figure 3 we show the size distributions for UV galaxies between 10 < log(M∗ /M" ) < 11. Th istogram shows the measured half-light radii o X/LBGs at z ∼ 1 while the distribution of size S red for BM/BX galaxies (z ∼ 2) are shown as i histogram. It can be seen from this plot that UV z galaxies at z ∼ 2 are smaller compared to simila e es at z ∼ 1. Specifically, the median half ligh f BM/BX galaxies in this mass range is 2.68 ± 0.1 gnificantly smaller than the median effective rad LEX/LBGs (4.42 ± 0.52 kpc). This means tha Redshift f UV-bright galaxies evolve by a median factor o Fig. 4.— Evolution of sizes of galaxies as a function of redshift. Each panel shows the size evolution for a narrow stellar mass bin. The gray symbols are star forming galaxies with spectroscopic redshifts in GOODS-N field. Blue stars are GALEX/LBGs (z ∼ 1) while the nfidence points. 6.2. Stellar Mass-Size Relation Evolution of the mass size relation to z = 3.5 in the GOODS North field now investigate how mass-size distribution of the7 z~1 z~2 z~3 ight galaxies compares to other galaxy populaWe S further check if the relation between stellar andi size of these galaxies exists to high redshift. stellar mass-size distributions of our samples are z ineFigure 5. We have divided our sample into three ft bins, 0.5 < z < 1.5, 1.5 < z < 2.5, 2.5 < z < 3.5. ight galaxies are color coded the same as Figure 4. and dotted lines in each panel Stellar Mass show the mass-size n from Shen et al. (2003) for star forming galaxies rly-type galaxies at z ∼ 0, respectively. The gray Fig. 5.— Stellar mass size distribution for UV-bright galaxies in different redshift bins compared to the galaxies from CDF-south (Franx et al. 2008) (gray dots). The color symbols represented here are the same as Fig. 4. The solid and dotted black lines are the size-mass relations for star forming and quiescent galaxies respectively at z ∼ 0 from Shen et al. (2003). The solid brown lines show the median sizes in narrow mass bins for all galaxies from CDF-S. The UV bright galaxies are in general larger than normal field galaxies at the same mass. uiescent galaxies respectively at z ∼ 0 from Shen et al. (2003). The solid brown lines show the median sizes xiesFig. from5.— CDF-S. Themass UV bright galaxies arefor in UV-bright general larger than normal field redshift galaxies bins at thecompared same mass. Stellar size distribution galaxies in different to the galaxies from CDF-south (Franx et al. 2008) (gray dots). The color symbols represented here are the same as Fig. 4. The solid and dotted black lines are the size-mass relations for star forming and quiescent galaxies respectively at z ∼ 0 from Shen et al. (2003). The solid brown lines show the median sizes in narrow mass bins for all galaxies from CDF-S. The UV bright galaxies are in general larger than normal field galaxies at the same mass. 6.2. Stellar Mass-Size Relation We now investigate how mass-size distribution z~1 z~2 z ~ of 3 the V-bright galaxies compares to other galaxy populaons. S We further check if the relation between stellar assi and size of these galaxies exists to high redshift. The stellar mass-size distributions of our samples are z hown in Figure 5. We have divided our sample into three e dshift bins, 0.5 < z < 1.5, 1.5 < z < 2.5, 2.5 < z < 3.5. V-bright galaxies are color coded the same as Figure 4. olid and dotted lines in each panel show the mass-size Stellar for Mass lation from Shen et al. (2003) star forming galaxies axies (r ∝ M ). In the highe use UV-bright galaxies fromgalaxies at z ∼ 0, respectively. The gray nd early-type (α = 0.32 ± 0.06). Table 2 lists meter to the mass size relation ymbols are sampleα of galaxies in CDFSample Redshift highofmass late typethe galaxiesK (r -selected ∝M ). In the highe for slopes the mass-size relaGALEX/LBG < z <9.8 1.4 0.19 ± 0.05 bin and (z ∼there 3), we galaxies0.6 from insest areredshift consistent is use UV-bright (Franx et al. 2008). outh with stellar masses >21.4lists 10 < z < 2.7 M 0.30 " ± 0.06 find thethe best fit (α = 0.32 ±BM/BX 0.06). Table OurCDF-S resultsto confirm persisCDFs-UV Bright 2.5 < z < 3.5 0.32 ± 0.06 thefor best-fit power law parameter to the mass size relation tion star forming galaxies Sample Redshift CDF-S α omparing our with1.4relathe from alsBzK < z < 3.2galaxies 0.31 ± 0.09 of UV-bright galaxies. The results slopes of the mass-size GALEX/LBG 0.6 < z < 1.4 0.19 ± 0.05 tion or at not different bins are consistent and there is ether other redshift star formBM/BX 1.4 < z <to 2.7 0.30 0.06 dshift have same size-mass no significant evolution. Our results confirm persisws ustheto see where ourthegalaxies lie relative a ±purely stellar mass-size relation for the UV-bright galaxies from GOODS-N field and CDF-South in three redshift the size-mass relation for star forming galaxies at z ∼ 0 from Shen et al. (2003). The color symbols are n narrow mass bins and the error bars show one σ (68%) dispersion. The dashed-dotted lines are the best to the individual UV-bright galaxies. The dotted lines are the median sizes in narrow mass bins for all Fig 5). This plot shows that the derived half-light radii of UV-bright galaxies from both fields are in place Fig. 6.— Comparison of the stellar mass-size relation for the UV-bright galaxies from GOODS-N field and CDF-South in three redshift up to z ∼ 3. bins. The black solid lines are the size-mass relation for star forming galaxies at z ∼ 0 from Shen et al. (2003). The color symbols are 0.4 median of UV-bright galaxies in narrow mass bins and the error bars show one σ (68%) dispersion. The dashed-dotted lines are the best TABLE 2 dotted lines are the median sizes in narrow mass bins for all powere law fits using re ∝ M α to the individual UV-bright galaxies. The Best fits power law parameter for the stellar - size galaxies from both fields are in place galaxies from CDF-S (Same as Fig 5). This plot shows that the derived half-light radii of mass UV-bright relation and agreement with each other up to z ∼ 3. e 0.4 TABLE 2 Best fits power law parameter for the stellar mass - size relation Note. Power law parameter α is defined as re ∝ M α . 8 mass size relation for star forming Mosleh al. . 7.— Stellar sBzKetgalaxies circles). The BM/BX galaxies and SMGs are marked densitywith is more ti sample of ga and pink circles respectively. The red squares are theusing median firms that the colo he mass-size relation of sBzK sample with one σ dispersion. surface density an green dashed-dotted line is the best fit to the BM/BX galaxshifts. The sBzK galaxies have a similar size-mass relation to the 6.4. BX galaxies. The solid line shows the mass-size relation for S Since GOODS-N orming galaxies at z ∼ 0 from Shen et al. (2003). compare their ma i at z ∼ 2. As Figu sizes of the SMG z could be due to the significant overlap between galaxiesthe of similar lightet radiial. of all SM selectede galaxies and sBzK galaxies (e.g. Reddy agreement with th BM/BX galaxies kpc). The media masses of 1010 − the BM/BX of at errors are comput We further com galaxies and BM top panel, the his 5). We note that stellar masses can have significant ertainties depending on the methods used to calculate m. We verify that by using the stellar mass estimates m Reddy et al. (2006) for UV-bright galaxies, the sizeStellar Mass s distribution these same region Fig. 7.—of Stellar mass sizegalaxies relation for starcovers forming sBzKthe galaxies (gray circles). The BM/BX galaxies and SMGs are marked with Sinceoptical GOODS-N includes 14UV-bright SMGs with the rest-frame sizes of the SMGs and ethods usedCDFS. to calculate are from The gray symbols are all galaxies from CDFS and the black triangles are galaxies from G Sizes Submm Since GOODS-N includes 14their SMGs redshifts, weofUV-sel that blue galaxies having lowergalaxies. surface density. Right panel The with color (zGalaxies −6.4. K) versus surface density fo compare mass and sizes to the e stellar mass estimates 850 6.4. Sizes of : Submm the galaxies, green squares are the BM/BX galaxies from GOODS-N and the brown circles are pseudo BM/BX from bright the sizecompare their mass and sizes to the UV-selected galaxies 6.4. Sizes of Submm Galaxies at z ∼ 2. As Figure 4 illustrates, the opti 7. DISCUSSION Since GOODS-N includes 14 Since GOODS-N includes 14 SMGs with redshifts, we S s covers the same region TABLE at zpanel ∼ 2.of Figure Ascompare Figuretheir 4sizes illustrates, the optical rest-frame of and the SMGs (pink diamonds) and compare their mass and sizes to t 7.1. The growth of star-forming galaxies middle mass sizes to the UV-selected galaxies Median sizes of diff Since GOODS-N includes 14 SMGs with redshifts, we sizes of the SMGs (pink diamonds) UV-selected sults are robust against galaxies of similar mass are comparable. Th at z ∼and 2. galaxies As Figure 4rest-frame illustrate We study the size evolution of with spectroat z ∼ 2. As Figure 4 illustrates, the optical compare mass and sizes to the UV-selected Sample galaxies Redshift r masses. scopic redshifts between z ∼ 0.5 − 3.5. Our results are light radii of all SMGs is 2.90 ± 0.45 wh galaxies oftheir similar mass are comparable. The median half sizes of the SMGs (pink sizes of the SMGs (pink diamonds) and UV-selected GALEX/LBG 0.6 kpc < z diam < 1.4 at z radii ∼ 2.ofAs Figure 4 illustrates, rest-frame summarized in Figuregalaxies 10.the As optical this plot illustrates, at BM/BX 1.4 < zcomp < 2.7 of similar mass are agreement with the median optical rest-fram light all SMGs is 2.90 ± 0.45 kpc which is in good galaxies of similar mass are comparable. The median half e Density each epoch, the diamonds) median sizes of UV-bright galaxies (color LBG 2.7 < z < 3.5 sizes of the SMGs (pink and UV-selected light radii of all SMGs is 2.90 light radii of all SMGs is 2.90 ± 0.45 kpc which is BM/BX galaxies over thesizes mass with thesquares) median rest-frame /M"of ) <the 110.5in are withoptical stellar masses 10 < log(M CDFS < good z rang <± 1.5 0 of agreement Franx et al. (2008) ∗whole galaxies of similar mass comparable. The median half CDFS 1.5 <of zSMG < 2.5 larger (byare athe median factor ofrange 0.45effective ± 0.09) than quiescent agreement with the median optic agreement with median optical rest-frame sizes the en BM/BX stellar massgalaxies surface kpc). The median radii of over the whole mass (2.68 ± 0.25 CDFS 2.5 < z < 3.5 galaxies in a2.90 similar mass range selected from CDF-S (red laxies to z radii ∼ 3. They 10whole 11 light of all SMGs is ± 0.45 kpc which is in good BM/BX galaxies over the whole BM/BX galaxies over the mass range (2.68 ± 0.25 − 10 is 2.65 ± 0.56 which masses of 10 Quiescent(CDFS) 0.5 < z kpc). The median effective radii of SMGs with stellar = circles). The red triangle is the median sizes of quiescent < 1.5 lower surface densities Quiescent(CDFS) 1.5 < z <rad 2 kpc). The median effective radii ofmedian SMGs with stellar kpc). Thesame effective agreement with the optical rest-frame sizes of the 10 11median galaxies studied in van Dokkum et al. (2008b) (VD08 the BM/BX of at the mass range (2.6 dicated that the color of − 10of 10is10 2.65 ± 0.56 which is similar to masses of 10masses Quiescent(VD08) 2 < z < 2.5 11 10 11 11 − 10 is 2.65 ± 0.56 which is similar − 10 is ± masses of 10 M2.65 entally with the galaxies stellar hearafter) with a median stellar mass of 1.7 × 10 BM/BX over the whole mass range (2.68 ± 0.25 " SMG 0.5 <resam z <to 3. errors are computed using bootstrap BM/BXthe of at the same mass range (2.68±0.19). The and median redshift of 2.3. Table 3 lists the median half ass.the = BM/BX of at the same mass range (2.68±0.19). The the BM/BX of at the same Notes. The median sizes mass of samp kpc). The median effective radii of SMGs with stellar We further compare the size distribution 10 11 errors computed bootstrap resampling. − 10 M! ex massesresampling. between lightusing radii for UV-bright and quiescent galaxies10using seen in boots tween color are and stellar errors are computed using bootstrap errors are computed 10 11 (van Dokkum et al. time 2008b) and SMG galaxies and BM/BX galaxies in Figure Figure 10. The growth of UV-bright galaxies with is -forming and quiescent − 10 is 2.65 ± 0.56 which is similar to masses of 10 We further We compare the size distributions ofcompare sub-mm is all galaxies at the stellar mad further compare the size distributions ofsame sub-mm We further the size in Figure 8. In the left also illustrated in this figure. The dashed line shows that forming sBzKand galaxies top panel, the histograms show the size d the BM/BX of at the same mass range (2.68±0.19). The galaxies BM/BX galaxies in Figure 9. In the galaxies and BM/BX galaxies in Figure 9. In the versus the galaxies scaled up their sizesBM/BX towards lower galaxies and galaxies 50 ) is plotted MGs are marked with UV-bright for galaxies in our sample. We BM/BX galaxies SMGs. In the botto −1.11±0.13 and errors are computed using bootstrap resampling. BzK galaxies . alaxies at redshift ∼ 1. redshifts as (1 + z) top panel, the histograms show the size distribution of top panel, the histograms show the distribution of stellar e relation forthe starmedian forming sBzK galaxies top size panel, histograms show squares are is athe relation between ma normalized cumulative distribution functio marked with Previous studies (Franx et al. 2008; Kauffmann et al. alaxies from GOODS-N X BM/BX galaxies SMGs areand marked with BM/BX galaxies and SMGs. In galaxies the bottom panel, We further compare the size distributions of sub-mm galaxies at 0.5 < z < 3.5.the Th with one σ and dispersion. galaxies SMGs. In the bottom panel, the BM/BX and SMGs. In the median 2003) reported that there is a correlation between color he blue stars and brown ectively. The red squares are the median for both samples. As plot shows, forthis both9. spectroscopic andthe phot to the BM/BX galaxnormalized cumulative distribution functions are shown galaxies and BM/BX galaxies in Figure In the normalized cumulative distribut normalized cumulative distribution functions are atshown and stellar mass surface density of galaxies boththat low there i Gs) and their analogues Our results verify ofdispersion. sBzK sample with one σ dispersion. e-mass relation to the tions ofAs SMGs are comparable with z ∼rs for both samples. this plot shows, the size distribuM/BX galaxand high redshifts. However, the results based on photoright panel, the relafor both samples. As this plot top panel, the histograms show the size distribution of of the slope of the size-mass ine is the best fit to the BM/BX galaxfor both samples. Asshowthis plot shows, the size distribumass-size relation for Fig. 9.— Top panel: Histograms the distribution of sizes of ation to the K) and surface density metric redshifts can be uncertain especially for 2 star formgalaxies and the SMGs the same tions of SMGs with zfollow ∼ The evolution ofUV-bright the relation have a similar size-mass relation to are the comparable g different estimates of stellar masses. v-z z-k We study the size evolution of galaxies with spectroopic redshifts between z ∼ 0.5 − 3.5. Our results are Surface Density ummarized in 6.3. FigureColor 10. As -this plot illustrates, at ach epoch, the median sizes of UV-bright galaxies (color Evolution of the mass sizeresults to z = 3.5 in of the GOODS North field ne of with thestellar surprising Franx 11 are et al. 9 (2008) quares) masses 10 <relation log(M ∗ /M" ) < rger a median factor of 0.45 ±between 0.09) than quiescent the(bytight correlation stellar mass surface alaxies in a similar range selected from CDF-S (red 2 mass z ~ 1 zto ~ 2 z ∼ 3. They ity (M /r ) and color of galaxies rcles). The∗ redetriangle is the median sizes of quiescent alaxiesthat studied in vangalaxies Dokkum et have al. (2008b) (VD08 wed bluer lower surface densities 11 earafter) with a median stellar mass of 1.7 × 10 M" red quiescent They that the color o nd median redshift of ones. 2.3. Table 3 lists indicated the median half ght radii for UV-bright and quiescent galaxies seen in xies correlates more fundamentally with the stellar igure 10. The growth of UV-bright galaxies with time is than the mass. sosurface illustrateddensity in this figure. The dashed line shows that scaled up their sizesbetween towards lower eV-bright showgalaxies the tight relation color and stellar dshifts as (1 + z)−1.11±0.13 . surface density both Previous studies (Franxfor et al. 2008; star-forming Kauffmann et al. and quiescent 10(V − z ) and surface 11between Fig. 8.— Left panel : The correlation between colorcorrelation density for Figure galaxiescolor in the redshift range of 0.5 < z < 1.5 003) reported that there is a ∼ 10 − 10 in 8. In the left xies with M " and stellar masses 10 < M/M < 10 in GOODS-N field. The blue stars are GALEX (LBGs) from GOODS-N and the brown circles Stellar Mass Surface Density are from CDFS. The gray symbols are all galaxies from CDFS and the black triangles are galaxies from GOODS-N. The plots indicates nd stellar mass surface of: Thegalaxies low that blue galaxies having lower surface density density. Right panel color (z − K) at versus both surface density for galaxies at 1.5 < z < 2.5, as lndthe observed color (V −z ) is plotted versus the the green squares are the BM/BX galaxies from GOODS-N606 and the brown circles are pseudo BM/BX from CDF-S. 850 high redshifts. However, the results based on photoTABLE 3 of different ar mass surface density for galaxies at samples redshift ∼ 1 etric redshifts can be uncertain especially forMedian starsizesform10 ! 11 606 850 850 mass and We study the size evolution of galaxies with spectroscopic redshifts between z ∼ 0.5 − 3.5. Our results are The ste summarized10in Figure 10. As this plot illustrates, at Mosleh et al. shown in each epoch, the median sizes of UV-bright galaxies (color squares) with stellar masses 10 < log(M∗ /M" ) < 11 are galaxies. redshift Since BzK b 08) tend to represent mas larger (by a median factor of 0.45 ± 0.09) than quiescent ace UV-brigh that they appear large galaxies in a similar mass range selected from CDF-S (red hey rected forSolid differingand ste circles). The red triangle is the median sizes of quiescent ties parison to be made. galaxies studied in van Dokkum et al. (2008b) (VD08 r of relation f Our results also show 11 lar hearafter) with a median stellar mass of 1.7 × 10 M" half light and radii ofearly 2.90 ± and median redshift of 2.3. Table 3 lists the median half sizes of t Fig. 3.— distribution of UV-bright galaxies with stellarframe optical light Size radii for UV-bright and quiescent galaxies seen in lar symbols is in agreement with a ass 10 < log(M /M ) < 11 at z ∼ 1 (blue histogram) and ∗ " Figure 10. The growth of UV-bright galaxies with time is ent (2010) where they wi use South ∼ 2 (green histogram). The half light radii of UV-bright galaxeft also illustrated in this figure. The dashed line shows that ing and show that th Comparin sthe (GALEX(LBGs)) at zscaled ∼ 1 are largersizes than BM/BX UV-bright galaxies up their towards lowergalaxies at SMGs and UV-bright −1.11±0.13 . ∼∼1.2. redshifts as (1 + z) parable. lows The typical us th Previous studies (Franx et al. 2008; Kauffmann et al. S-N H -band (rest-frame opt (2010) is mass-sele 2.8 ± 0.4 wh 2003) reported that there is a correlation between color wn surements. Almaini e and stellar mass of surface of galaxies at)both low at z ∼ 3 ues ithin mass range 10 density < log(M < 11 of each p ∗ /M" of submm galaxies wit and high redshifts. However, the results based on photoelaour sample. The median half-light radius of these 4 mass frame optical and bin found ity metric redshifts can be uncertain especially for star formand LBG assiveinggalaxies kpc, 0.82 ± 0.23 smallerof the SMGs ith galaxies. is By 2.22 means± of 0.61 our large sample of galaxies z ∼ 1 and have larger median ste res with secure redshifts, we have confirmed that the tight Redshift han z ∼ 2 BM/BX galaxies. We perform a power-law radii com galaxies (also mentione Fig. 10.— The median sizes of UV-bright galaxies can correlation between color and stellar mass surface den-(squares) −1.11±0.13 suggests higher stellar m as a function of redshifts for galaxies with stellar masses 1010 < ∝ (1 + z) taveon the evolution and find r For galax sity size of galaxies that holds out to high redshifts; as the 11 UV-bright galaxies evolve as M/M! < 10 in GOODS-N field. eThe red filled circles are quito UV bright galaxies. escent galaxiesof from CDF-S with similar mass range and and thestellar mass densities blue starstudy forming galaxies are between these ver range 0.6 ! z ! 3.5. fer two by gala a red those triangleof is red quiescent sample from Dokkum et al. (2008b) ace smaller than quiescent ones.van11This verifies by itself allow conclus nst Size Conclusion dashed linewith with median stellar masses of 1.7 × 10 M . The The size-redshift relation for star-forming galaxies 2 res tween theand two populat shows the best fitting size evolution to the UV-bright galaxies ! Summary Quantifying the size mass evolution of galaxies without potential uncertainties of photometric redshift. UV-Bright galaxies evolve strongly with redshift. UV-Bright galaxies are significantly larger than quiescent galaxies. At the same mass, the median difference is 0.45 ± 0.09. The LBG, BM/BX and GALEX/LBG samples show smooth evolution with redshift. The SMGs have half-light radii similar to UV-Bright galaxies of the same mass. Draft version November 12, 2010 Preprint typeset using LATEX style emulateapj v. 5/25/10 THE EVOLUTION OF THE MASS-SIZE RELATION TO Z=3.5 FOR UV-BRIGHT GALAXIES AND SUB-MM GALAXIES IN THE GOODS-NORTH FIELD Moein Mosleh1 , Rik J. Williams 2 , Marijn Franx 1 , Mariska Kriek3 Draft version November 12, 2010 Abstract We study the evolution of the size - stellar mass relation for a large spectroscopic sample of galaxies in the GOODs North field up to z ∼ 3.5. The sizes of the galaxies are measured from Ks -band images (corresponding to rest-frame optical/NIR) from the Subaru 8m telescope. We reproduce earlier results based on photometric redshifts that the sizes of galaxies at a given mass evolve with redshift. Specifically, we compare sizes of UV-bright galaxies at a range of redshifts: Lyman break galaxies (LBGs) selected through the U-drop technique (z ∼ 2.5 − 3.5), BM/BX galaxies at z ∼ 1.5 − 2.5, and GALEX LBGs at low redshift (z ∼ 0.6 − 1.5). The median sizes of these UV-bright galaxies evolve as (1 + z)−1.11±0.13 between z ∼ 0.5 − 3.5. The UV-bright galaxies are significantly larger than quiescent galaxies at the same mass and redshift by 0.45 ± 0.09 dex. We also verify the correlation between color and stellar mass density of galaxies to high redshifts. The sizes of sub-mm galaxies in the same field are measured and compared with BM/BX galaxies. We find that median half-light radii of SMGs is 2.90 ± 0.45 kpc and there is little difference in their size distribution to the UV-bright star forming galaxies. Subject headings: galaxies: evolution – galaxies: high redshift – galaxies: structure arXiv: 1011.3042v1 1. INTRODUCTION Recent studies provide evidence that sizes of galax- based on photometric redshifts. Although techniques to construct galaxy spectral energy distributions (SEDs)