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We measure weak lensing cosmic shear power spectra from the three-year galaxy shear catalog of the Hyper Suprime-Cam (HSC) Subaru Strategic Program imaging survey. The shear catalog covers $416 \ \mathrm{deg}^2$ of the northern sky, with a mean $i$-band seeing of 0.59 arcsec and an effective galaxy number density of 15 $\mathrm{arcmin}^{-2}$ within our adopted redshift range. With an $i$-band magnitude limit of 24.5 mag, and four tomographic redshift bins spanning $0.3 \leq z_{\mathrm{ph}} \leq 1.5$ based on photometric redshifts, we obtain a high-significance measurement of the cosmic shear power spectra, with a signal-to-noise ratio of approximately 26.4 in the multipole range $300, Comment: 35 pages, 18 figures, 6 tables, for coordinated submission to PRD with other HSC Y3 weak lensing cosmology papers - see https://hsc-release.mtk.nao.ac.jp/doc/index.php/wly3/

We perform a blinded cosmology analysis with cosmic shear two-point correlation functions (2PCFs) measured from more than 25 million galaxies in the Hyper Suprime-Cam three-year shear catalog in four tomographic redshift bins ranging from 0.3 to 1.5. After conservative masking and galaxy selection, the survey covers 416 deg$^2$ of the northern sky with an effective galaxy number density of 15 arcmin$^{-2}$ over the four redshift bins. The 2PCFs adopted for cosmology analysis are measured in the angular range: $7.1 < \theta/{\rm arcmin} < 56.6$ for $\xi_+$ and $31.2, Comment: 36 pages, 29 figures, 4 tables, for coordinated submission to PRD with other HSC Y3 weak lensing cosmology papers - see https://hsc-release.mtk.nao.ac.jp/doc/index.php/wly3/

We use the Sloan Digital Sky Survey (SDSS) BOSS galaxies and their overlap with approximately 416 sq. degree of deep $grizy$-band imaging from the Subaru Hyper Suprime-Cam Survey (HSC). We measure three two-point correlations that form the basis of the cosmological inference presented in our companion papers, Miyatake et al. and Sugiyama et al. We use three approximately volume limited subsamples of spectroscopic galaxies by their $i$-band magnitude from the SDSS-BOSS: LOWZ (0.1, Comment: 30 pages, 24 figures, for coordinated submission to PRD with other HSC Y3 weak lensing cosmology papers - see https://hsc-release.mtk.nao.ac.jp/doc/index.php/wly3/ , added references to companion papers

We present cosmological parameter constraints from a blind joint analysis of three two-point correlation functions measured from the Year 3 Hyper Suprime-Cam (HSC-Y3) imaging data, covering 416 deg$^2$, and the SDSS DR11 spectroscopic galaxies spanning the redshift range $[0.15, 0.70]$. We subdivide the SDSS galaxies into three volume-limited samples separated in redshift, each of which acts as a large-scale structure tracer characterized by the measurement of the projected correlation function, $w_{\rm p}(R)$. We also use the measurements of the galaxy-galaxy weak lensing signal $\Delta \Sigma(R)$ for each of these SDSS samples which act as lenses for a secure sample of source galaxies selected from the HSC-Y3 shape catalog based on their photometric redshifts. We combine these measurements with the cosmic shear correlation functions, $\xi_{\pm}(\vartheta)$, measured for our HSC source sample. We model these observables with the minimal bias model of the galaxy clustering observables in the context of a flat $\Lambda$CDM cosmology. We use conservative scale cuts, $R>12$ and $8~h^{-1}$Mpc, for $\Delta\Sigma$ and $w_{\rm p}$, respectively, where the minimal bias model is valid, in addition to conservative prior on the residual bias in the mean redshift of the HSC photometric source galaxies. Our baseline analysis yields $S_8=0.775^{+0.043}_{-0.038}$ (68% C.I.) for the $\Lambda$CDM model, after marginalizing over uncertainties in other parameters. Our value of $S_8$ is consistent with that from the Planck 2018 data, but the credible interval of our result is still relatively large. Our results are statistically consistent with those of a companion paper, which extends this analysis to smaller scales with an emulator-based halo model., Comment: 29 pages, 17 figures, 4 tables, for coordinated submission to PRD with other HSC Y3 weak lensing cosmology papers - see https://hsc-release.mtk.nao.ac.jp/doc/index.php/wly3/

We investigate the stellar mass-dependence of the galaxy size-dark matter halo radius relation for low redshift galaxies using weak gravitational lensing measurements. Our sample consists of $\sim$38,000 galaxies more massive than $10^{8} {\rm M}_{\odot}h^{-2}$ and within $z, 19 pages, 11 figures, submitted to the MNRAS

Galaxy clusters, being the most massive objects in the Universe, exhibit the strongest alignment with the large-scale structure. However, mis-identification of members due to projection effects from the large scale structure can occur. We studied the impact of projection effects on the measurement of the intrinsic alignment of galaxy clusters, using galaxy cluster mock catalogs. Our findings showed that projection effects result in a decrease of the large scale intrinsic alignment signal of the cluster and produce a bump at $r_p\sim 1h^{-1}/Mpc$, most likely due to interlopers and missed member galaxies. This decrease in signal explains the observed similar alignment strength between bright central galaxies and clusters in the SDSS redMaPPer cluster catalog. The projection effect and cluster intrinsic alignment signal are coupled, with clusters having lower fractions of missing members or having higher fraction of interlopers exhibiting higher alignment signals in their projected shapes. We aim to use these findings to determine the impact of projection effects on galaxy cluster cosmology in future studies., Comment: 15 pages, 14 figures, Submitted to MNRAS

Which galaxies in the general population turn into active galactic nuclei (AGNs) is a keystone of galaxy formation and evolution. Thanks to SRG/eROSITA's contiguous 140 square degree pilot survey field, we constructed a large, complete, and unbiased soft X-ray flux-limited ($F_X>6.5\times 10^{-15}$ erg s$^{-1}$ cm$^{-2}$) AGN sample at low redshift, $0.05, Comment: 17 pages, 9 figures, 2 tables. A&A: Received: 19 December 2022 / Accepted: 21 March 2023

We assess the dark matter halo masses of luminous AGNs over the redshift range 0.2 to 1.2 using galaxy-galaxy lensing based on imaging data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). We measure the weak lensing signal of a sample of 8882 AGNs constructed using HSC and WISE photometry. The lensing detection around AGNs has a signal-to-noise ratio of 15. As expected, we find that the lensing mass profile is consistent with that of massive galaxies ($M_{*}\sim 10.8~M_\odot$). Surprisingly, the lensing signal remains unchanged when the AGN sample is split into low and high stellar mass hosts. Specifically, we find that the excess surface density (ESD) of AGNs, residing in galaxies with high stellar masses, significantly differs from that of the control sample. We further fit a halo occupation distribution model to the data to infer the posterior distribution of parameters including the average halo mass. We find that the characteristic halo mass of the full AGN population lies near the knee ($\rm log(M_h/h^{-1}M_{\odot})=12.0$) of the stellar-to-halo mass relation (SHMR). Illustrative of the results given above, the halo masses of AGNs residing in host galaxies with high stellar masses (i.e., above the knee of the SHMR) falls below the calibrated SHMR while the halo mass of the low stellar mass sample is more consistent with the established SHMR. These results indicate that massive halos with higher clustering bias tend to suppress AGN activity, probably due to the lack of available gas., Comment: 17 pages,10 figures, accepted for publication in the Astrophysical Journal

We present posterior sample redshift distributions for the Hyper Suprime-Cam Subaru Strategic Program Weak Lensing three-year (HSC Y3) analysis. Using the galaxies' photometry and spatial cross-correlations, we conduct a combined Bayesian Hierarchical Inference of the sample redshift distributions. The spatial cross-correlations are derived using a subsample of Luminous Red Galaxies (LRGs) with accurate redshift information available up to a photometric redshift of $z < 1.2$. We derive the photometry-based constraints using a combination of two empirical techniques calibrated on spectroscopic- and multiband photometric data that covers a spatial subset of the shear catalog. The limited spatial coverage induces a cosmic variance error budget that we include in the inference. Our cross-correlation analysis models the photometric redshift error of the LRGs to correct for systematic biases and statistical uncertainties. We demonstrate consistency between the sample redshift distributions derived using the spatial cross-correlations, the photometry, and the posterior of the combined analysis. Based on this assessment, we recommend conservative priors for sample redshift distributions of tomographic bins used in the three-year cosmological Weak Lensing analyses., 23 pages, 11 figures, 1 table, submitted to the MNRAS; comments welcome

We perform a cosmic shear analysis of HSC survey first-year data (HSC-Y1) using Complete Orthogonal Sets of E/B-Integrals (COSEBIs) to derive cosmological constraints. We compute E/B-mode COSEBIs from cosmic shear two-point correlation functions measured on an angular range of $4\arcmin, Comment: 23 pages, 19 figures, accepted for PASJ. arXiv admin note: substantial text overlap with arXiv:1906.06041

We perform a rigorous cosmology analysis on simulated type Ia supernovae (SN~Ia) and evaluate the improvement from including photometric host-galaxy redshifts compared to using only the "zspec" subset with spectroscopic redshifts from the host or SN. We use the Deep Drilling Fields (~50 deg^2) from the Photometric LSST Astronomical Time-Series Classification Challenge (PLaSTiCC), in combination with a low-z sample based on Data Challenge2 (DC2). The analysis includes light curve fitting to standardize the SN brightness, a high-statistics simulation to obtain a bias-corrected Hubble diagram, a statistical+systematics covariance matrix including calibration and photo-z uncertainties, and cosmology fitting with a prior from the cosmic microwave background. Compared to using the zspec subset, including events with SN+host photo-z results in i) more precise distances for z>0.5, ii) a Hubble diagram that extends 0.3 further in redshift, and iii) a 50 % increase in the Dark Energy Task Force figure of merit (FoM) based on the w0-wa CDM model. Analyzing 25 simulated data samples, the average bias on w0 and wa is consistent with zero. The host photo-z systematic of 0.01 reduces FoM by only 2 % because i) most z, 13 pages, 9 figures, 7 tables. Submitted to ApJ

We present cosmological parameter constraints from a blinded joint analysis of galaxy-galaxy weak lensing, $\Delta\!\Sigma(R)$, and projected correlation function, $w_\mathrm{p}(R)$, measured from the first-year HSC (HSC-Y1) data and SDSS spectroscopic galaxies over $0.150.75$ for the $\Delta\!\Sigma$ measurements, selected based on their photometric redshifts. For theoretical template, we use the "minimal bias" model for the cosmological clustering observables for the flat $\Lambda$CDM cosmological model. We compare the model predictions with the measurements in each redshift bin on large scales, $R>12$ and $8~h^{-1}\mathrm{Mpc}$ for $\Delta\!\Sigma(R)$ and $w_\mathrm{p}(R)$, respectively, where the perturbation theory-inspired model is valid. When we employ weak priors on cosmological parameters, without CMB information, we find $S_8=0.936^{+0.092}_{-0.086}$, $\sigma_8=0.85^{+0.16}_{-0.11}$, and $\Omega_\mathrm{m}=0.283^{+0.12}_{-0.035}$ for the flat $\Lambda$CDM model. Although the central value of $S_8$ appears to be larger than those inferred from other cosmological experiments, we find that the difference is consistent with expected differences due to sample variance, and our results are consistent with the other results to within the statistical uncertainties. (abriged), Comment: 24 pages, 19 figures, 4 tables, to be submitted to Phys. Rev. D

We present high-fidelity cosmology results from a blinded joint analysis of galaxy-galaxy weak lensing ($\Delta\!\Sigma$) and projected galaxy clustering ($w_{\rm p}$) measured from the Hyper Suprime-Cam Year-1 (HSC-Y1) data and spectroscopic Sloan Digital Sky Survey (SDSS) galaxy catalogs in the redshift range $0.15, Comment: 44 pages, 30 figures, 6 tables, submitted to Phys. Rev. D, YouTube video is available at https://www.youtube.com/watch?v=jRhQvuee97Q

Do cool-core (CC) and noncool-core (NCC) clusters live in different environments? We make novel use of H$��$ emission lines in the central galaxies of redMaPPer clusters as proxies to construct large (1,000's) samples of CC and NCC clusters, and measure their relative assembly bias using both clustering and weak lensing. We increase the statistical significance of the bias measurements from clustering by cross-correlating the clusters with an external galaxy redshift catalog from the Sloan Digital Sky Survey III, the LOWZ sample. Our cross-correlations can constrain assembly bias up to a statistical uncertainty of 6%. Given our H$��$ criteria for CC and NCC, we find no significant differences in their clustering amplitude. Interpreting this difference as the absence of halo assembly bias, our results rule out the possibility of having different large-scale (tens of Mpc) environments as the source of diversity observed in cluster cores. Combined with recent observations of the overall mild evolution of CC and NCC properties, such as central density and CC fraction, this would suggest that either the cooling properties of the cluster core are determined early on solely by the local (, 17 pages, 9 figures, 2 tables, to be submitted to ApJ; comments welcome

I discuss recent theoretical advances which have led us to suggest a physical definition for the boundary of dark matter halos. We propose using the "splashback radius" which corresponds to the apocenter of recently infalling material as a physical boundary for dark matter halos. We also present how the splashback radius can be detected in observations., This work was supported by the Japan Society for Promotion of Science grants JP15K17600 and JP16H01089., {"references":["Diemer & Kravtsov 2014","More, Diemer and Kravtsov 2015","More et al. 2016","Niikura et al. 2017","Fillmore & Golreich 1984","Bertschinger 1985","Vogelsberger et al. 2011","Mansfield et al. 2017","Diemer et al. 2017","Busch & White 2017","Baxter et al. 2017"]}

We study the properties of dark matter halos that contain star-forming galaxies at $1.43 \le z \le 1.74$ using the FMOS-COSMOS survey. The sample consists of 516 objects with a detection of the H$��$ emission line, that represent the star-forming population at this epoch having a stellar mass range of $10^{9.57}\le M_\ast/M_\odot \lesssim 10^{11.4}$ and a star formation rate range of $15\lesssim \mathrm{SFR}/(M_\odot \mathrm{yr^{-1}}) \lesssim 600$. We measure the projected two-point correlation function while carefully taking into account observational biases, and find a significant clustering amplitude at scales of $0.04$-$10~h^{-1}~\mathrm{cMpc}$, with a correlation length $r_0 = 5.21^{+0.70}_{-0.67}~h^{-1}~\mathrm{cMpc}$ and a bias $b=2.59^{+0.41}_{-0.34}$. We interpret our clustering measurement using a halo occupation distribution model. The sample galaxies appear to reside in halos with mass $M_\mathrm{h} = 4.6^{+1.1}_{-1.6}\times10^{12}~h^{-1}M_\odot$ on average that will likely become present-day halos of mass $M_\mathrm{h} (z=0) \sim2\times10^{13}~h^{-1}M_\odot$, equivalent to the typical halo mass scale of galaxy groups. We then confirm the decline of the stellar-to-halo mass ratio at $M_\mathrm{h}1$., 28 pages, 26 figures, submitted to ApJ

Primordial black holes (PBHs) have long been suggested as a viable candidate for the elusive dark matter (DM). The abundance of such PBHs has been constrained using a number of astrophysical observations, except for a hitherto unexplored mass window of $M_{\rm PBH}=[10^{-14},10^{-9}]M_\odot$. Here we carry out a dense-cadence (2~min sampling rate), 7 hour-long observation of the Andromeda galaxy (M31) with the Subaru Hyper Suprime-Cam to search for microlensing of stars in M31 by PBHs lying in the halo regions of the Milky Way (MW) and M31. Given our simultaneous monitoring of tens of millions of stars in M31, if such light PBHs make up a significant fraction of DM, we expect to find many microlensing events for the PBH DM scenario. However, we identify only a single candidate event, which translates into the most stringent upper bounds on the abundance of PBHs in the mass range $M_{\rm PBH}\simeq [10^{-11}, 10^{-6}]M_\odot$., Comment: 43 pages, 25 figures, 2 tables. Made significant revision of the microlensing event rate calculation taking into account both effects of finite source size and wave optics

We present and characterize the catalog of galaxy shape measurements that will be used for cosmological weak lensing measurements in the Wide layer of the first year of the Hyper Suprime-Cam (HSC) survey. The catalog covers an area of 136.9 deg$^2$ split into six fields, with a mean $i$-band seeing of $0.58$ arcsec and $5\sigma$ point-source depth of $i\sim 26$. Given conservative galaxy selection criteria for first year science, the depth and excellent image quality results in unweighted and weighted source number densities of 24.6 and 21.8 arcmin$^{-2}$, respectively. We define the requirements for cosmological weak lensing science with this catalog, then focus on characterizing potential systematics in the catalog using a series of internal null tests for problems with point-spread function (PSF) modeling, shear estimation, and other aspects of the image processing. We find that the PSF models narrowly meet requirements for weak lensing science with this catalog, with fractional PSF model size residuals of approximately $0.003$ (requirement: 0.004) and the PSF model shape correlation function $\rho_11^\circ$ scales that are sufficiently large as to require mitigation in cosmic shear measurements. Finally, we discuss the dominant systematics and the planned algorithmic changes to reduce them in future data reductions., Comment: 42 figures, 4 tables, v3 matches accepted version that will be published in PASJ (minor changes from v2). For high-resolution figures and cross-references with other HSC articles that will be in the same PASJ issue, please see the published version of the article

We present an optically-selected cluster catalog from the Hyper Suprime-Cam (HSC) Subaru Strategic Program. The HSC images are sufficiently deep to detect cluster member galaxies down to $M_*\sim 10^{10.2}M_\odot$ even at $z\sim 1$, allowing a reliable cluster detection at such high redshifts. We apply the CAMIRA algorithm to the HSC Wide S16A dataset covering $\sim 232$ deg$^2$ to construct a catalog of 1921 clusters at redshift $0.115$ that roughly corresponds to $M_{\rm 200m}\gtrsim 10^{14}h^{-1}M_\odot$. We confirm good cluster photometric redshift performance, with the bias and scatter in $��z/(1+z)$ being better than 0.005 and 0.01 over most of the redshift range, respectively. We compare our cluster catalog with large X-ray cluster catalogs from XXL and XMM-LSS surveys and find good correlation between richness and X-ray properties. We also study the miscentering effect from the distribution of offsets between optical and X-ray cluster centers. We confirm the high ($>0.9$) completeness and purity for high mass clusters by analyzing mock galaxy catalogs., 18 pages, 18 figures, accepted for publication in PASJ; cluster catalogs are available at http://www.slac.stanford.edu/~oguri/cluster/

We present a statistical study of the redshift evolution of the cluster galaxy population over a wide redshift range from 0.1 to 1.1, using $\sim 1900$ optically-selected CAMIRA clusters from $\sim 232$~deg$^2$ of the Hyper Suprime-Cam (HSC) Wide S16A data. Our stacking technique with a statistical background subtraction reveals color-magnitude diagrams of red-sequence and blue cluster galaxies down to faint magnitudes of $m_z\sim 24$. We find that the linear relation of red-sequence galaxies in the color-magnitude diagram extends down to the faintest magnitudes we explore with a small intrinsic scatter $��_{\rm int}(g-r), 18pages, 10 figures, accepted as PASJ special issue

FastSound is a galaxy redshift survey using the near-infrared Fiber Multi-Object Spectrograph (FMOS) mounted on the Subaru Telescope, targeting H$��$ emitters at $z \sim 1.18$--$1.54$ down to the sensitivity limit of H$��$ flux $\sim 2 \times 10^{-16} \ \rm erg \ cm^{-2} s^{-1}$. The primary goal of the survey is to detect redshift space distortions (RSD), to test General Relativity by measuring the growth rate of large scale structure and to constrain modified gravity models for the origin of the accelerated expansion of the universe. The target galaxies were selected based on photometric redshifts and H$��$ flux estimates calculated by fitting spectral energy distribution (SED) models to the five optical magnitudes of the Canada France Hawaii Telescope Legacy Survey (CFHTLS) Wide catalog. The survey started in March 2012, and all the observations were completed in July 2014. In total, we achieved $121$ pointings of FMOS (each pointing has a $30$ arcmin diameter circular footprint) covering $20.6$ deg$^2$ by tiling the four fields of the CFHTLS Wide in a hexagonal pattern. Emission lines were detected from $\sim 4,000$ star forming galaxies by an automatic line detection algorithm applied to 2D spectral images. This is the first in a series of papers based on FastSound data, and we describe the details of the survey design, target selection, observations, data reduction, and emission line detections., 12 pages, 9 figures, and 2 tables, accepted for PASJ

It is generally assumed that the central galaxy in a dark matter halo, that is, the galaxy with the lowest specific potential energy, is also the brightest halo galaxy (BHG), and that it resides at rest at the centre of the dark matter potential well. This central galaxy paradigm (CGP) is an essential assumption made in various fields of astronomical research. In this paper we test the validity of the CGP using a large galaxy group catalogue constructed from the Sloan Digital Sky Survey. For each group we compute two statistics, ${\cal R}$ and ${\cal S}$, which quantify the offsets of the line-of-sight velocities and projected positions of brightest group galaxies relative to the other group members. By comparing the cumulative distributions of $|{\cal R}|$ and $|{\cal S}|$ to those obtained from detailed mock group catalogues, we rule out the null-hypothesis that the CGP is correct. Rather, the data indicate that in a non-zero fraction $f_{\rm BNC}(M)$ of all haloes of mass $M$ the BHG is not the central galaxy, but instead, a satellite galaxy. In particular, we find that $f_{\rm BNC}$ increases from $\sim 0.25$ in low mass haloes ($10^{12} h^{-1} {\rm M_{\odot}} \leq M \lsim 2 \times 10^{13} h^{-1}{\rm M_{\odot}}$) to $\sim 0.4$ in massive haloes ($M \gsim 5 \times 10^{13} h^{-1} {\rm M_{\odot}}$). We show that these values of $f_{\rm BNC}$ are uncomfortably high compared to predictions from halo occupation statistics and from semi-analytical models of galaxy formation. We end by discussing various implications of a non-zero $f_{\rm BNC}(M)$, with an emphasis on the halo masses inferred from satellite kinematics., Comment: 17 pages, 11 figures. Axes labels of Fig. 3 fixed

Using estimates of dark halo masses from satellite kinematics, weak gravitational lensing, and halo abundance matching, combined with the Tully-Fisher and Faber-Jackson relations, we derive the mean relation between the optical, V_opt, and virial, V_200, circular velocities of early- and late-type galaxies at redshift z~0. For late-type galaxies V_opt ~ V_200 over the velocity range V_opt=90-260 km/s, and is consistent with V_opt = V_maxh (the maximum circular velocity of NFW dark matter haloes in the concordance LCDM cosmology). However, for early-type galaxies V_opt \ne V_200, with the exception of early-type galaxies with V_opt simeq 350 km/s. This is inconsistent with early-type galaxies being, in general, globally isothermal. For low mass (V_opt < 250 km/s) early-types V_opt > V_maxh, indicating that baryons have modified the potential well, while high mass (V_opt > 400 km/s) early-types have V_opt < V_maxh. Folding in measurements of the black hole mass - velocity dispersion relation, our results imply that the supermassive black hole - halo mass relation has a logarithmic slope which varies from ~1.4 at halo masses of ~10^{12} Msun/h to ~0.65 at halo masses of 10^{13.5} Msun/h. The values of V_opt/V_200 we infer for the Milky Way and M31 are lower than the values currently favored by direct observations and dynamical models. This offset is due to the fact that the Milky Way and M31 have higher V_opt and lower V_200 compared to typical late-type galaxies of the same stellar masses. We show that current high resolution cosmological hydrodynamical simulations are unable to form galaxies which simultaneously reproduce both the V_opt/V_200 ratio and the V_opt-M_star (Tully-Fisher/Faber-Jackson) relation., 17 pages, 7 figures, accepted to MNRAS

We use galaxy groups selected from the Sloan Digital Sky Survey (SDSS) together with mass models for individual groups to study the galaxy-galaxy lensing signals expected from galaxies of different luminosities and morphological types. We compare our model predictions with the observational results obtained from the SDSS by Mandelbaum et al. (2006) for the same samples of galaxies. The observational results are well reproduced in a $\Lambda$CDM model based on the WMAP 3-year data, but a $\Lambda$CDM model with higher $\sigma_8$, such as the one based on the WMAP 1-year data,significantly over-predicts the galaxy-galaxy lensing signal. We model, separately, the contributions to the galaxy-galaxy lensing signals from different galaxies: central versus satellite, early-type versus late-type, and galaxies in halos of different masses. We also examine how the predicted galaxy-galaxy lensing signal depends on the shape, density profile, and the location of the central galaxy with respect to its host halo., Comment: 16 pages, 8 figures, accepted for publication on MNRAS

Galaxy clustering and galaxy-galaxy lensing probe the connection between galaxies and their dark matter haloes in complementary ways. On one hand, the halo occupation statistics inferred from the observed clustering properties of galaxies are degenerate with the adopted cosmology. Consequently, different cosmologies imply different mass-to-light ratios for dark matter haloes. On the other hand, galaxy-galaxy lensing yields direct constraints on the actual mass-to-light ratios and it can be used to break this degeneracy, and thus to constrain cosmological parameters. In this paper we establish the link between galaxy luminosity and dark matter halo mass using the conditional luminosity function (CLF). We constrain the CLF parameters using the galaxy luminosity function and the luminosity dependence of the correlation lengths of galaxies. The resulting CLF models are used to predict the galaxy-galaxy lensing signal. For a cosmology with $(��_{\rm m},��_8)=(0.238,0.734)$, the model accurately fits the galaxy-galaxy lensing data obtained from the SDSS. For a comparison cosmology with $(��_{\rm m},��_8)=(0.3,0.9)$, however, we can accurately fit the luminosity function and clustering properties of the galaxy population, but the model predicts mass-to-light ratios that are too high, resulting in a strong overprediction of the galaxy-galaxy lensing signal. We conclude that the combination of galaxy clustering and galaxy-galaxy lensing is a powerful probe of the galaxy-dark matter connection, with the potential to yield tight constraints on cosmological parameters. Since this method mainly probes the mass distribution on non-linear scales, it is complementary to constraints obtained from the galaxy power-spectrum, which mainly probes the large-scale (linear) matter distribution., 20 pages, 11 figures, submitted to MNRAS