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We report CFHT/SITELLE imaging Fourier Transform Spectrograph observations of the Brightest Cluster Galaxy (BCG) of galaxy cluster Abell 2390 at z=0.228. The BCG displays a prominent cone of emission in H$\alpha$, H$\beta$, [NII], and [OII] to the North-West with PA = 42$^o$, 4.4 arcsec in length (15.9 kpc), which is associated with elongated and asymmetric Chandra soft X-ray emission. The H$\alpha$ flux map also contains a "hook" of H$\alpha$ and [NII] emission resulting in a broadened northern edge to the cone. Using SITELLE/LUCI software we extract emission line flux, velocity, velocity dispersion, and continuum maps, and utilize them to derive flux ratio maps to determine ionization mechanisms and dynamical information in the BCG's emission line region. The Baldwin-Phillips-Terlevich diagnostics on the BCG cone indicate a composite ionization origin of photoionization due to star formation and shock. Strong LINER-like emission is seen in the nuclear region which hosts an AGN. As Abell 2390 is a cool-core cluster, we suggest that the cooling flow is falling onto the central BCG and interacting with the central AGN. The AGN produces jets that inflate "bubbles" of plasma in the ICM, as is often observed in local galaxy clusters. Furthermore, combining signs of AGN activities from radio, optical emission line and X-ray data over a large range of physical scale, we find evidence for three possible episodes of AGN activity in different epochs associated with the Abell 2390 BCG., Comment: 15 pages, 13 figures, accepted by MNRAS

We study the angular correlation function of star-forming galaxies and properties of their host dark matter halos at z>1 using the Hyper-Suprime Cam (HSC) SSP survey. We use [OII] emitters identified using two narrow-band (NB) filters, NB816 and NB921, in the Deep/UltraDeep layers, which respectively cover large angular areas of 16.3 deg^2 and 16.9 deg^2. Our sample contains 8302 and 9578 [OII] emitters at z=1.19 (NB816) and z=1.47 (NB921), respectively. We detect a strong clustering signal over a wide angular range, 0.001 < \theta < 1 [deg], with the bias $b=1.61^{+0.13}_{-0.11}$ (z=1.19) and $b=2.09^{+0.17}_{-0.15}$ (z=1.47). We also find a clear deviation of the correlation from a simple power-law form. To interpret the measured clustering signal, we adopt a halo occupation distribution (HOD) model that is constructed to explain the spatial distribution of galaxies selected by a star formation rate. The observed correlation function and number density are simultaneously explained by the best-fitting HOD model. From the constrained HOD model, the average mass of halos hosting the [OII] emitters is derived to be $\log{M_{eff}/(h^{-1}M_\odot)}=12.70^{+0.09}_{-0.07}$ and $12.61^{+0.09}_{-0.05}$ at z=1.19 and 1.47, respectively, which will become halos with the present-day mass, $M\sim 1.5 \times 10^{13}h^{-1}M_\odot$. The satellite fraction of the [OII] emitter sample is found to be $f_{sat}\sim 0.15$. All these values are consistent with the previous studies of similar samples, but we obtain tighter constraints even in a larger parameter space due to the larger sample size from the HSC. The results obtained for host halos of [OII] emitters in this paper enable the construction of mock galaxy catalogs and the systematic forecast study of cosmological constraints from upcoming emission line galaxy surveys such as the Subaru PFS survey., Comment: 21 pages, 13 figures, 5 tables, accepted to PASJ

The Subaru Hyper Suprime-Cam (HSC) Strategic Survey is the latest-generation multi-band optical imaging survey for galaxy evolution and structure formation. The "Ultra-Deep" component of the HSC survey provides $grizy$ broad-band images over $\sim3.4$ deg$^2$ to detection limits of $\sim26$-28 AB, along with narrow-band images, in the COSMOS and the SXDS fields. These images provide an unprecedented combination of depths and area coverage, for the studies galaxies up to $z\sim7$. However, the lack of coverage at $, Comment: 24 pages, 12 figures, accepted for publication on ApJS

We utilize the ALMA-MaNGA QUEnch and STar formation (ALMaQUEST) survey to investigate the kpc-scale scaling relations, presented as the resolved star-forming MS (rSFMS: ΣSFR versus Σ*), the resolved Schmidt–Kennicutt relation (rSK: ΣSFR versus Σ H 2 ), and the resolved molecular gas MS (rMGMS: Σ H 2 versus Σ*), for 11,478 star-forming and 1414 retired spaxels (oversampled by a factor of ∼20) located in 22 GV and 12 MS galaxies. For a given galaxy type (MS or GV), the retired spaxels are found to be offset from the sequences formed by the star-forming spaxels on the rSFMS, rSK, and rMGMS planes, toward lower absolute values of sSFR, SFE, and f H 2 by ∼1.1, 0.6, and 0.5 dex. The scaling relations for GV galaxies are found to be distinct from that of the MS galaxies, even if the analyses are restricted to the star-forming spaxels only. It is found that, for star-forming spaxels, sSFR, SFE, and f H 2 in GV galaxies are reduced by ∼0.36, 0.14, and 0.21 dex, respectively, compared to those in MS galaxies. Therefore, the suppressed sSFR/SFE/f gas in GV galaxies is associated with not only an increased proportion of retired regions in GV galaxies but also a depletion of these quantities in star-forming regions. Finally, the reduction of SFE and f H 2 in GV galaxies relative to MS galaxies is seen in both bulge and disk regions (albeit with larger uncertainties), suggesting that, statistically, quenching in the GV population may persist from the inner to the outer regions.

We present a detailed weak-lensing and X-ray study of the Frontier Fields galaxy cluster Abell 370, one of the most massive known lenses on the sky, using wide-field BRz Subaru/Sprime-Cam and Chandra X-ray observations. By combining two-dimensional (2D) shear and azimuthally averaged magnification constraints derived from Subaru data, we perform a lensing mass reconstruction in a free-form manner, which allows us to determine both radial structure and 2D morphology of the cluster mass distribution. In a triaxial framework assuming a Navarro-Frenk-White density profile, we constrain the intrinsic structure and geometry of the cluster halo by forward modeling the reconstructed mass map. We obtain a halo mass $M_{200}=(1.54 \pm 0.29)\times 10^{15}h^{-1}M_\odot$, a halo concentration $c_{200}=5.27 \pm 1.28$, and a minor-major axis ratio $q_a=0.62 \pm 0.23$ with uninformative priors. Using a prior on the line-of-sight alignment of the halo major axis derived from binary merger simulations constrained by multi-probe observations, we find that the data favor a more prolate geometry with lower mass and lower concentration. From triaxial lens modeling with the line-of-sight prior, we find a spherically enclosed gas mass fraction of $f_\mathrm{gas}=(8.4 \pm 1.0)\%$ at $0.7h^{-1}$ Mpc $\sim 0.7r_{500}$. When compared to the hydrostatic mass estimate from Chandra observations, our triaxial weak-lensing analysis yields spherically enclosed mass ratios of $1-b \equiv M_\mathrm{HE}/M_\mathrm{WL} = 0.56 \pm 0.09$ and $0.51 \pm 0.09$ at $0.7h^{-1}$ Mpc with and without using the line-of-sight prior, respectively. Since the cluster is in a highly disturbed dynamical state, this represents the likely maximum level of hydrostatic bias in galaxy clusters., Comment: Version accepted by ApJ; 26 pages (main body) + 8 pages (appendices and references), 20 figures, 9 tables

The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still under debate. We use a sample of 1156 galaxies in galaxy pairs or mergers (hereafter `pairs') from the MaNGA survey. This pair sample is selected by the velocity offset, projected separation, and morphology, and is further classified into four cases along the merger sequence based on morphological signatures. We then identify a total of 61 (5.5%) AGNs in pairs based on the emission-line diagnostics. No evolution of the AGN fraction is found, either along the merger sequence or compared to isolated galaxies (5.0%). We observe a higher fraction of passive galaxies in galaxy pairs, especially in the pre-merging cases, and associate the higher fraction to their environmental dependence. The isolated AGN and AGN in pairs show similar distributions in their global stellar mass, star formation rate (SFR), and central [OIII] surface brightness. AGNs in pairs show radial profiles of increasing specific SFR and declining Dn4000 from center to outskirts, and no significant difference from the isolated AGNs. This is clearly different from star-forming galaxies (SFGs) in our pair sample, which show enhanced central star formation, as reported before. AGNs in pairs have lower Balmer decrements at outer regions, possibly indicating less dust attenuation. Our findings suggest that AGNs likely follow an inside-out quenching and the merger impact on the star formation in AGNs is less prominent than in SFGs., 23 pages, 13 figures, accepted by ApJ

We use machine learning techniques to classify galaxy merger stages, which can unveil physical processes that drive the star formation and active galactic nucleus (AGN) activities during galaxy interaction. The sample contains 4,690 galaxies from the integral field spectroscopy survey SDSS-IV MaNGA, and can be separated to 1,060 merging galaxies and 3630 non-merging or unclassified galaxies. For the merger sample, there are 468, 125, 293, and 174 galaxies in (1) incoming pair phase, (2) first pericentric passage phase, (3) aproaching or just passing the apocenter, and (4) final coalescence phase or post-mergers. With the information of projected separation, line-of-sight velocity difference, SDSS gri images, and MaNGA Ha velocity map, we are able to classify the mergers and their stages with good precision, which is the most important score to identify interacting galaxies. For the 2-phase classification (binary; non-merger and merger), the performance can be high (precision>0.90) with LGBMClassifier. We find that sample size can be increased by rotation, so the 5-phase classification (non-merger, 1, 2, 3, and 4 merger stages) can be also good (precision>0.85). The most important features come from SDSS gri images. The contribution from MaNGA Ha velocity map, projected separation, and line-of-sight velocity difference can further improve the performance by 0-20%. In other words, the image and the velocity information are sufficient to capture important features of galaxy interactions, and our results can apply to the entire MaNGA data as well as future all-sky surveys., accepted for publication in ApJ

We use machine learning techniques to investigate their performance in classifying active galactic nuclei (AGNs), including X-ray selected AGNs (XAGNs), infrared selected AGNs (IRAGNs), and radio selected AGNs (RAGNs). Using known physical parameters in the Cosmic Evolution Survey (COSMOS) field, we are able to well-established training samples in the region of Hyper Suprime-Cam (HSC) survey. We compare several Python packages (e.g., scikit-learn, Keras, and XGBoost), and use XGBoost to identify AGNs and show the performance (e.g., accuracy, precision, recall, F1 score, and AUROC). Our results indicate that the performance is high for bright XAGN and IRAGN host galaxies. The combination of the HSC (optical) information with the Wide-field Infrared Survey Explorer (WISE) band-1 and WISE band-2 (near-infrared) information perform well to identify AGN hosts. For both type-1 (broad-line) XAGNs and type-1 (unobscured) IRAGNs, the performance is very good by using optical to infrared information. These results can apply to the five-band data from the wide regions of the HSC survey, and future all-sky surveys., accepted for publication in ApJ

Effect of gravitational magnification on the measurement of distance modulus of type Ia supernovae is presented. We investigate a correlation between magnification and Hubble residual to explore how the magnification affects the estimation of cosmological parameters. We estimate magnification of type Ia supernovae in two distinct methods: one is based on convergence mass reconstruction under the weak lensing limit and the other is based on the direct measurement from galaxies distribution. Both magnification measurements are measured from Subaru Hyper Suprime-Cam survey catalogue. For both measurements, we find no significant correlation between Hubble residual and magnification. Furthermore, we correct for the apparent supernovae fluxes obtained by Supernova Legacy Survey 3-year sample using direct measurement of the magnification. We find $\Omega_{\rm m0} = 0.287 ^{+0.104} _{-0.085}$ and $w = -1.161 ^{+0.595}_{-0.358}$ for supernovae samples corrected for lensing magnification when we use photometric redshift catalogue of Mizuki, while $\Omega_{\rm m0} = 0.253 ^{+0.113} _{-0.087}$ and $w = -1.078 ^{+0.498} _{-0.297}$ for DEmP photo-z catalogue. Therefore, we conclude that the effect of magnification on the supernova cosmology is negligibly small for the current surveys; however, it has to be considered for the future supernova survey like LSST., Comment: 13 pages, 10 figures, 2 tables

We revisit the dependence of covering factor (CF) of dust torus on physical properties of active galactic nuclei (AGNs) by taking into account an AGN polar dust emission. The CF is converted from a ratio of infrared (IR) luminosity contributed from AGN dust torus ($L_{\rm IR}^{\rm torus}$) and AGN bolometric luminosity ($L_{\rm bol}$), by assuming a non-linear relation between luminosity ratio and intrinsic CF. We select 37,181 type 1 quasars at $z < 0.7$ from the Sloan Digital Sky Survey Data Release 16 quasar catalog. Their $L_{\rm bol}$, black hole mass ($M_{\rm BH}$), and Eddington ratio ($\lambda_{\rm Edd}$) are derived by spectral fitting with QSFit. We conduct spectral energy distribution decomposition by using X-CIGALE with clumpy torus and polar dust model to estimate $L_{\rm IR}^{\rm torus}$ without being affected by the contribution of stellar and AGN polar dust to IR emission. For 5720 quasars whose physical quantities are securely determined, we perform a correlation analysis on CF and (i) $L_{\rm bol}$, (ii) $M_{\rm BH}$, and (iii) $\lambda_{\rm Edd}$. As a result, anti-correlations for CF-$L_{\rm bol}$, CF-$M_{\rm BH}$, and CF-$\lambda_{\rm Edd}$ are confirmed. We find that incorporating the AGN polar dust emission makes those anti-correlations stronger which are compared to those without considering it. This indicates that polar dust wind provably driven by AGN radiative pressure is one of the key components to regulate obscuring material of AGNs., Comment: 20 pages, 14 figures, and 4 tables, accepted for publication in ApJ. Physical properties (e.g., BH mass, Eddington ratio, IR luminosity) of 37,181 quasars at z < 0.7 selected from the SDSS DR16 will be available as a Machine-readable table

We investigate the physical properties--such as the stellar mass, SFR, IR luminosity, X-ray luminosity, and hydrogen column density--of MIR galaxies and AGN at $z < 4$ in the 140 deg$^2$ field observed by SRG/eROSITA through the eFEDS survey. By cross-matching the WISE 22 $μ$m (W4)-detected sample and the eFEDS X-ray point-source catalog, we find that 692 extragalactic objects are detected by eROSITA. We have compiled a multiwavelength dataset. We have also performed (i) an X-ray spectral analysis, (ii) SED fitting using X-CIGALE, (iii) 2D image-decomposition analysis using Subaru HSC images, and (iv) optical spectral fitting with QSFit to investigate the AGN and host-galaxy properties. For 7,088 WISE W4 objects that are undetected by eROSITA, we have performed an X-ray stacking analysis to examine the typical physical properties of these X-ray faint and/or probably obscured objects. We find that (i) 82% of the eFEDS-W4 sources are classified as X-ray AGN with $\log\,L_{\rm X} >$ 42 erg s$^{-1}$; (ii) 67% and 24% of the objects have $\log\,(L_{\rm IR}/L_{\odot}) > 12$ and 13, respectively; (iii) the relationship between $L_{\rm X}$ and the 6 $μ$m luminosity is consistent with that reported in previous works; and (iv) the relationship between the Eddington ratio and $N_{\rm H}$ for the eFEDS-W4 sample and a comparison with a model prediction from a galaxy-merger simulation indicates that approximately 5% of the eFEDS-W4 sources in our sample are likely to be in an AGN-feedback phase, in which strong radiation pressure from the AGN blows out the surrounding material from the nuclear region. Thanks to the wide area coverage of eFEDS, we have been able to constrain the ranges of the physical properties of the WISE W4 sample of AGNs at $z < 4$, providing a benchmark for forthcoming studies on a complete census of MIR galaxies selected from the full-depth eROSITA all-sky survey., 18 pages, 19 figures, and 3 tables, accepted to appear on A&A, Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)., Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org.

The large Integral Field Spectroscopy surveys have allowed the classification of ionizing sources of emission lines on sub-kiloparsec scales. In this work, we define two non-parametric parameters, quiescence (F q ) and its concentration (C q ), to quantify the strength and the spatial distribution of the quenched areas, respectively, traced by the LI(N)ER regions with low EW(Hα). With these two measurements, we classify MaNGA galaxies into inside-out and outside-in quenching types according to their locations on the F q versus C q plane and we measure the fraction of inside-out (outside-in) quenching galaxies as a function of halo mass. We find that the fraction of galaxies showing inside-out quenching increases with halo mass, irrespective of stellar mass or galaxy type (satellites versus centrals). In addition, high-stellar-mass galaxies exhibit a greater fraction of inside-out quenching compared to low-stellar-mass ones in all environments. In contrast, the fraction of outside-in quenching does not depend on halo mass. Our results suggest that morphological quenching may be responsible for the inside-out quenching seen in all environments. On the other hand, the flat dependence of the outside-in quenching on halo mass could be a mixed result of ram pressure stripping and galaxy mergers. Nevertheless, for a given environment and stellar mass, the fraction of inside-out quenching is systematically greater than that of outside-in quenching, suggesting that inside-out quenching is the dominant quenching mode in all environments.

The redshifts of galaxies are a key attribute that is needed for nearly all extragalactic studies. Since spectroscopic redshifts require additional telescope and human resources, millions of galaxies are known without spectroscopic redshifts. Therefore, it is crucial to have methods for estimating the redshift of a galaxy based on its photometric properties, the so-called photo-$z$. We developed NetZ, a new method using a Convolutional Neural Network (CNN) to predict the photo-$z$ based on galaxy images, in contrast to previous methods which often used only the integrated photometry of galaxies without their images. We use data from the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) in five different filters as training data. The network over the whole redshift range between 0 and 4 performs well overall and especially in the high-$z$ range better than other methods on the same data. We obtain an accuracy $|z_\text{pred}-z_\text{ref}|$ of $\sigma = 0.12$ (68% confidence interval) with a CNN working for all galaxy types averaged over all galaxies in the redshift range of 0 to $\sim$4. By limiting to smaller redshift ranges or to Luminous Red Galaxies (LRGs), we find a further notable improvement. We publish more than 34 million new photo-$z$ values predicted with NetZ here. This shows that the new method is very simple and fast to apply, and, importantly, covers a wide redshift range limited only by the available training data. It is broadly applicable and beneficial to imaging surveys, particularly upcoming surveys like the Rubin Observatory Legacy Survey of Space and Time which will provide images of billions of galaxies with similar image quality as HSC., Comment: 10 pages, 11 figures, 1 catalog, published in A&A

Green valley galaxies represent the population that is likely to transition from the star-forming to the quiescent phases. To investigate the role of the environment in quenching star formation, we use the wide-field data from the Hyper Suprime-Cam Strategic Subaru Proposal survey to quantify the frequency of green valley galaxies in different environments and their redshift evolution. We find that the green valley fraction, in general, is less than 20% in any redshift and environment. The green valley fraction, when normalized to the total population, is higher in the field than that in groups or clusters and decreases with a decreasing redshift and increasing mass. The lower fraction of transitional galaxies in denser environments could be a consequence of the lack of star-forming galaxies, which could be the progenitors of green valley galaxies. To assess the effect of the environment on star formation quenching, we define the effective green valley fraction as the ratio of the number of green valley galaxies to that of nonquiescent galaxies only. The effective green valley fraction for field galaxies is lower than that for group or cluster galaxies, which reveals a strong positive mass dependence and mild redshift evolution. Moreover, the specific star formation rate (sSFR) is reduced by 0.1-0.3 dex in groups or clusters. Our results thus imply that an ongoing slow quenching process has been acting in the dense environment since z~1., Comment: 18 pages, 6 figures, and 5 tables. Accepted by ApJ

We present an ALMA study of the ~180 brightest sources in the SCUBA-2 map of the COSMOS field from the S2COSMOS survey, as a pilot study for AS2COSMOS - a full survey of the ~1,000 sources in this field. In this pilot we have obtained 870-um continuum maps of an essentially complete sample of the brightest 182 sub-millimetre sources (S_850um=6.2mJy) in COSMOS. Our ALMA maps detect 260 sub-millimetre galaxies (SMGs) spanning a range in flux density of S_870um=0.7-19.2mJy. We detect more than one SMG counterpart in 34+/-2 per cent of sub-millimetre sources, increasing to 53+/-8 per cent for SCUBA-2 sources brighter than S_850um>12mJy. We estimate that approximately one-third of these SMG-SMG pairs are physically associated (with a higher rate for the brighter secondary SMGs, S_870um>3mJy), and illustrate this with the serendipitous detection of bright [CII] 157.74um line emission in two SMGs, AS2COS0001.1 & 0001.2 at z=4.63, associated with the highest significance single-dish source. Using our source catalogue we construct the interferometric 870um number counts at S_870um>6.2mJy. We use the extensive archival data of this field to construct the multiwavelength spectral energy distribution of each AS2COSMOS SMG, and subsequently model this emission with MAGPHYS to estimate their photometric redshifts. We find a median photometric redshift for the S_870um>6.2mJy AS2COSMOS sample of z=2.87+/-0.08, and clear evidence for an increase in the median redshift with 870-um flux density suggesting strong evolution in the bright-end of the 870um luminosity function., Submitted to MNRAS, comments welcome. Figures 1, 4, A1 degraded to comply with size limits

We utilize the Hyper Suprime-Cam (HSC) Wide Survey to explore the properties of galaxies located in the voids identified from the Baryon Oscillation Spectroscopic Survey (BOSS) up to z~0.7. The HSC reaches i~25, allowing us to characterize the void galaxies down to 10$^{9.2}$ solar mass. We find that the revised void galaxy densities, when including faint galaxies in voids defined by bright galaxies, are still underdense compared to the mean density from the entire field. In addition, we classify galaxies into star-forming, quiescent, and green valley populations, and find that void galaxies tend to have slightly higher fractions of star-forming galaxies under the mass and redshift control, although the significance of this result is only moderate (2$\sigma$). However, when we focus on the star-forming population, the distribution of the specific star formation rate (sSFR) of void galaxies shows little difference from that of the control galaxies. Similarly, the median sSFR of star-forming void galaxies is also in good agreement with that of the star-forming control galaxies. Moreover, the effective green valley fraction of void galaxies, defined as the number of green valley galaxies over the number of nonquiescent galaxies, is comparable to that of the control ones, supporting the suggestion that void and control galaxies evolve under similar physical processes and quenching frequencies. Our results thus favor a scenario of the galaxy assembly bias., Comment: 17 pages, 10 figures, 3 tables, ApJ accepted

We present a structural study of 182 obscured Active Galactic Nuclei (AGNs) at z, Accepted for publication in MNRAS Letter

著者人数: 40名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 山田, 亨), Number of authors: 40 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Yamada, Toru), Accepted: 2019-09-03, 資料番号: SA1190163000

The origin of the star forming main sequence ( i.e., the relation between star formation rate and stellar mass, globally or on kpc-scales; hereafter SFMS) remains a hotly debated topic in galaxy evolution. Using the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we show that for star forming spaxels in the main sequence galaxies, the three local quantities, star-formation rate surface density (\sigsfr), stellar mass surface density (\sigsm), and the \h2~mass surface density (\sigh2), are strongly correlated with one another and form a 3D linear (in log) relation with dispersion. In addition to the two well known scaling relations, the resolved SFMS (\sigsfr~ vs. \sigsm) and the Schmidt-Kennicutt relation (\sigsfr~ vs. \sigh2; SK relation), there is a third scaling relation between \sigh2~ and \sigsm, which we refer to as the `molecular gas main sequence' (MGMS). The latter indicates that either the local gas mass traces the gravitational potential set by the local stellar mass or both quantities follow the underlying total mass distributions. The scatter of the resolved SFMS ($\sigma \sim 0.25$ dex) is the largest compared to those of the SK and MGMS relations ($\sigma \sim$ 0.2 dex). A Pearson correlation test also indicates that the SK and MGMS relations are more strongly correlated than the resolved SFMS. Our result suggests a scenario in which the resolved SFMS is the least physically fundamental and is the consequence of the combination of the SK and the MGMS relations., Comment: 4 figures, 1 table, accepted by ApJL

Galaxy interactions are often accompanied by an enhanced star formation rate (SFR). Since molecular gas is essential for star formation, it is vital to establish whether, and by how much, galaxy interactions affect the molecular gas properties. We investigate the effect of interactions on global molecular gas properties by studying a sample of 58 galaxies in pairs and 154 control galaxies. Molecular gas properties are determined from observations with the JCMT, PMO, CSO telescopes, and supplemented with data from the xCOLD GASS and JINGLE surveys at $^{12}$CO(1-0) and $^{12}$CO(2-1). The SFR, gas mass ($M_\mathrm{H_{2}}$), and gas fraction ($f_{gas}$) are all enhanced in galaxies in pairs by $\sim$ 2.5 times compared to the controls matched in redshift, mass, and effective radius, while the enhancement of star formation efficiency (SFE $\equiv$ SFR/$M_{H_{2}}$) is less than a factor of 2. We also find that the enhancements in SFR, $M_{H_{2}}$ and $f_{gas}$ increase with decreasing pair separation and are larger in systems with smaller stellar mass ratio. Conversely, the SFE is only enhanced in close pairs (separation $, Comment: 26 pages, 11 figures, accepted for publication in ApJ

Environmental effects are crucial to the understanding of the evolution of galaxies in dense environments, such as galaxy clusters. Using the large field-of-view of SITELLE, the unique imaging fourier transform spectrograph at CFHT, we are able to obtain 2D spectral information for a large and complete sample of cluster galaxies out to the infall region. We describe a pipeline developed to identify emission line galaxies (ELGs) from the datacube using cross-correlation techniques. We present results based on the spatial offsets between the emission-line regions and stellar continua in ELGs from two z$\sim$0.25 galaxy clusters, Abell 2390 and Abell 2465. We find a preference in the offsets being pointed away from the cluster center. Combining the two clusters, there is a 3$\sigma$ excess for high-velocity galaxies within the virial radius having the offsets to be pointed away from the cluster center. Assuming the offset being a proxy for the velocity vector of a galaxy, as expected from ram pressure stripping, this excess indicates that ram pressure stripping occurs most effectively during the first passage of an infalling galaxy, leading to the quenching of its star formation. We also find that, outside the virial region, the continuum-normalized H$\alpha$ line flux for infalling galaxies with large offsets are on average lower than those with small or no measurable offset, further supporting ram pressure as a dominant quenching mechanism during the initial infall stages., Comment: 25 pages, 18 figures, accepted for publication in ApJ

Galaxy integrated H{\alpha} star formation rate-stellar mass relation, or SFR(global)-M*(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different H{\alpha} powering sources for ~1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially-resolved relation between H{\alpha} surface density ({\Sigma}H{\alpha}(all)) and stellar mass surface density ({\Sigma}*(all)) progressively turns over at high {\Sigma}*(all) end for increasing M*(global) and bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated H{\alpha}(global)-M*(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated H{\alpha}(HII)-M*(HII) and spatially-resolved {\Sigma}H{\alpha}(HII)-{\Sigma}*(HII) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. Analysis of the fractional contribution of non-star-formation sources to total H{\alpha} luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR-M* relation critically depends on their global properties (M*(global) and B/T) and relative abundances of various ionizing sources within the galaxies., Comment: 11 pages, 5 figures, accepted for publication in ApJ

We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalog covering 137deg$^2$ of the sky. Thanks to the high effective galaxy number density of $\sim$17 arcmin$^{-2}$ even after conservative cuts such as magnitude cut of $i, Comment: 43 pages, 21 figures, accepted for publication in PASJ

We use data from 1222 late-type star-forming galaxies in the SDSS IV MaNGA survey to identify regions in which the gas-phase metallicity is anomalously-low compared to expectations from the tight empirical relation between metallicity and stellar surface mass-density at a given stellar mass. We find anomalously low metallicity (ALM) gas in 10% of the star-forming spaxels, and in 25% of the galaxies in the sample. The incidence rate of ALM gas increases strongly with both global and local measures of the specific star-formation rate, and is higher in lower mass galaxies and in the outer regions of galaxies. The incidence rate is also significantly higher in morphologically disturbed galaxies. We estimate that the lifetimes of the ALM regions are a few hundred Myr. We argue that the ALM gas has been delivered to its present location by a combination of interactions, mergers, and accretion from the halo, and that this infusion of gas stimulates star-formation. Given the estimated lifetime and duty cycle of such events, we estimate that the time-averaged accretion rate of ALM gas is similar to the star-formation rate in late type galaxies over the mass-range M$_* \sim10^9$ to 10$^{10}$ M$_{\odot}$., Comment: Accepted by ApJ

We study the role of cold gas in quenching star formation in the green valley by analyzing ALMA 12 CO (1-0) observations of three galaxies with resolved optical spectroscopy from the MaNGA survey. We present resolution-matched maps of the star formation rate and molecular gas mass. These data are used to calculate the star formation efficiency (SFE) and gas fraction (f gas ) for these galaxies separately in the central "bulge" regions and outer disks. We find that, for the two galaxies whose global specific star formation rate (sSFR) deviates most from the star formation main sequence, the gas fraction in the bulges is significantly lower than that in their disks, supporting an "inside-out" model of galaxy quenching. For the two galaxies where SFE can be reliably determined in the central regions, the bulges and disks share similar SFEs. This suggests that a decline in f gas is the main driver of lowered sSFR in bulges compared to disks in green valley galaxies. Within the disks, there exist common correlations between the sSFR and SFE and between sSFR and f gas on kiloparsec scales - the local SFE or f gas in the disks declines with local sSFR. Our results support a picture in which the sSFR in bulges is primarily controlled by f gas , whereas both SFE and f gas play a role in lowering the sSFR in disks. A larger sample is required to confirm if the trend established in this work is representative of the green valley as a whole., The work is supported by the Ministry of Science & Technology of Taiwan under the grant MOST 103-2112-M-001-031-MY3 and 106-2112-M-001-034. R.M. and F.B. acknowledge support by the UK Science and Technology Facilities Council (STFC). R.M. acknowledges ERC Advanced Grant 695671 "QUENCH."

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 $\Delta z/(1+z)$ 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., Comment: 18 pages, 18 figures, accepted for publication in PASJ; cluster catalogs are available at http://www.slac.stanford.edu/~oguri/cluster/

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2m Subaru telescope on the summit of Maunakea in Hawaii. A team of scientists from Japan, Taiwan and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg$^2$ in five broad bands ($grizy$), with a $5\,\sigma$ point-source depth of $r \approx 26$. The Deep layer covers a total of 26~deg$^2$ in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg$^2$). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey., Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the coordinates of HSC-Wide spring equatorial field in Table 5

Photometric redshifts are a key component of many science objectives in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). In this paper, we describe and compare the codes used to compute photometric redshifts for HSC-SSP, how we calibrate them, and the typical accuracy we achieve with the HSC five-band photometry (grizy). We introduce a new point estimator based on an improved loss function and demonstrate that it works better than other commonly used estimators. We find that our photo-z's are most accurate at 0.2, Comment: 30 pages, 15 figures, 5 tables, moderate revision, accepted for publication in PASJ

The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including the nature of dark matter and dark energy. The survey has been awarded 300 nights of observing time at the Subaru Telescope and it started in March 2014. This paper presents the first public data release of HSC-SSP. This release includes data taken in the first 1.7 years of observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and ~27.0 mag, respectively (5sigma for point sources). All the layers are observed in five broad bands (grizy), and the Deep and UltraDeep layers are observed in narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF photometry (rms) both internally and externally (against Pan-STARRS1), and ~10 mas and 40 mas internal and external astrometric accuracy, respectively. Both the calibrated images and catalogs are made available to the community through dedicated user interfaces and database servers. In addition to the pipeline products, we also provide value-added products such as photometric redshifts and a collection of public spectroscopic redshifts. Detailed descriptions of all the data can be found online. The data release website is https://hsc-release.mtk.nao.ac.jp/., 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PASJ

We measure the stellar mass function (SMF) and stellar mass density of galaxies in the COSMOS field up to z 6. We select them in the near-IR bands of the COSMOS2015 catalogue, which includes ultra-deep photometry from UltraVISTA-DR2, SPLASH, and Subaru/Hyper Suprime-Cam. At z> 2.5 we use new precise photometric redshifts with error σz = 0.03(1 + z) and an outlier fraction of 12%, estimated by means of the unique spectroscopic sample of COSMOS ( 100 000 spectroscopic measurements in total, more than one thousand having robust zspec> 2.5). The increased exposure time in the DR2, along with our panchromatic detection strategy, allow us to improve the completeness at high z with respect to previous UltraVISTA catalogues (e.g. our sample is >75% complete at 1010 ℳ☉ and z = 5). We also identify passive galaxies through a robust colour-colour selection, extending their SMF estimate up to z = 4. Our work provides a comprehensive view of galaxy-stellar-mass assembly between z = 0.1 and 6, for the first time using consistent estimates across the entire redshift range. We fit these measurements with a Schechter function, correcting for Eddington bias. We compare the SMF fit with the halo mass function predicted from ΛCDM simulations, finding that at z> 3 both functions decline with a similar slope in thehigh-mass end. This feature could be explained assuming that mechanisms quenching star formation in massive haloes become less effective at high redshifts; however further work needs to be done to confirm this scenario. Concerning the SMF low-mass end, it shows a progressive steepening as it moves towards higher redshifts, with α decreasing from -1.47+0.02-0.02 at z ≃ 0.1 to -2.11+0.30-0.13 at z ≃ 5. This slope depends on the characterisation of the observational uncertainties, which is crucial to properly remove the Eddington bias. We show that there is currently no consensus on the method to quantify such errors: different error models result in different best-fit Schechter parameters. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under ESO programme ID 179.A-2005 and on data products produced by TERAPIX and the Cambridge Astronomy Survey Unit on behalf of the UltraVISTA consortium (http://ultravista.org/). Based on data produced by the SPLASH team from observations made with the Spitzer Space Telescope (http://splash.caltech.edu).

We present physical properties of radio galaxies (RGs) with $f_{\rm 1.4 GHz} >$ 1 mJy discovered by Subaru Hyper Supreme-Cam (HSC) and VLA Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at $0 < z \leq 1.7$ with HSC counterparts in about 100 deg$^2$, we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150 MHz). We derived their color excess ($E (B-V)_{*}$), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity ($q_{\rm IR}$), and radio spectral index ($\alpha_{\rm radio}$) that are derived from the SED fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of AGN component. We found that $E (B-V)_{*}$, SFR, and IR luminosity clearly depend on redshift while stellar mass, $q_{\rm IR}$, and $\alpha_{\rm radio}$ do not significantly depend on redshift. Since optically-faint ($i_{\rm AB} \geq 21.3$) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared to optically-bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population., Comment: 30 pages, 20 figures, and 4 tables, accepted for publication in ApJS. The catalog and SED template of radio galaxies will be accessible through an online service

We present the COSMOS2015 catalog which contains precise photometric redshifts and stellar masses for more than half a million objects over the 2deg$^{2}$ COSMOS field. Including new $YJHK_{\rm s}$ images from the UltraVISTA-DR2 survey, $Y$-band from Subaru/Hyper-Suprime-Cam and infrared data from the Spitzer Large Area Survey with the Hyper-Suprime-Cam Spitzer legacy program, this near-infrared-selected catalog is highly optimized for the study of galaxy evolution and environments in the early Universe. To maximise catalog completeness for bluer objects and at higher redshifts, objects have been detected on a $\chi^{2}$ sum of the $YJHK_{\rm s}$ and $z^{++}$ images. The catalog contains $\sim 6\times 10^5$ objects in the 1.5 deg$^{2}$ UltraVISTA-DR2 region, and $\sim 1.5\times 10^5$ objects are detected in the "ultra-deep stripes" (0.62 deg$^{2}$) at $K_{\rm s}\leq 24.7$ (3$\sigma$, 3", AB magnitude). Through a comparison with the zCOSMOS-bright spectroscopic redshifts, we measure a photometric redshift precision of $\sigma_{\Delta z/(1+z_s)}$ = 0.007 and a catastrophic failure fraction of $\eta=0.5$%. At $3, Comment: Accepted for publication in ApJ

We present a list of galaxy-scale lens candidates including a highly probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC) imaging survey. We combine HSC imaging with the blended-spectra catalog from the Galaxy And Mass Assembly (GAMA) survey to identify lens candidates, and use lens mass modeling to confirm the candidates. We find 46 matches between the HSC S14A_0b imaging data release and the GAMA catalog. Ten of them are probable lens systems according to their morphology and redshifts. There is one system with an interacting galaxy pair, HSC J084928+000949, that has a valid mass model. We predict the total mass enclosed by the Einstein radius of $\sim0.72$" ($\sim1.65$kpc) for this new expected lens system to be $\sim10^{10.59}M_{\odot}$. Using the photometry in the {\it grizy} bands of the HSC survey and stellar population synthesis modeling with a Salpeter stellar initial mass function, we estimate the stellar mass within the Einstein radius to be $\sim10^{10.46}\,M_{\odot}$. We thus find a dark matter mass fraction within the Einstein radius of $\sim25\%$. Further spectroscopy or high-resolution imaging would allow confirmation of the nature of these lens candidates. The particular system with the interacting galaxy pair, if confirmed, would provide an opportunity to study the interplay between dark matter and stars as galaxies build up through hierarchical mergers., 10 pages, 5 figures

We measure the H{\alpha} and [OIII] emission line properties as well as specific star-formation rates (sSFR) of spectroscopically confirmed 33 cannot be fully explained in a picture of cold accretion driven growth. We find a progressively increasing [OIII]{\lambda}5007/H{\beta} ratio out to z~6, consistent with the ratios in local galaxies selected by increasing H{\alpha} EW (i.e., sSFR). This demonstrates the potential of using "local high-z analogs" to investigate the spectroscopic properties and relations of galaxies in the re-ionization epoch., Comment: 18 pages, 11 figures, 3 tables

We present stacking analyses on our ALMA deep 1.1 mm imaging in the SXDF using 1.6 {\mu}m and 3.6 {\mu}m selected galaxies in the CANDELS WFC3 catalog. We detect a stacked flux of ~0.03-0.05 mJy, corresponding to LIR < 10^11 Lsun and a star formation rate (SFR) of ~ 15 Msun/yr at z = 2. We find that galaxies brighter in the rest-frame near-infrared tend to be also brighter at 1.1 mm, and galaxies fainter than m[3.6um] = 23 do not produce detectable 1.1 mm emission. This suggests a correlation between stellar mass and SFR, but outliers to this correlation are also observed, suggesting strongly boosted star formation or extremely large extinction. We also find tendencies that redder galaxies and galaxies at higher redshifts are brighter at 1.1 mm. Our field contains z ~ 2.5 H-alpha emitters and a bright single-dish source. However, we do not find evidence of bias in our results caused by the bright source. By combining the fluxes of sources detected by ALMA and fluxes of faint sources detected with stacking, we recover a 1.1 mm surface brightness of up to 20.3 +/- 1.2 Jy/deg, comparable to the extragalactic background light measured by COBE. Based on the fractions of optically faint sources in our and previous ALMA studies and the COBE measurements, we find that approximately half of the cosmic star formation may be obscured by dust and missed by deep optical surveys, Much deeper and wider ALMA imaging is therefore needed to better constrain the obscured cosmic star formation history., Comment: accepted for publication in ApJ

We present a submillimetre survey of seven high-z galaxy clusters (0.64

We present our study on the spatially resolved H_alpha and M_star relation for 536 star-forming and 424 quiescent galaxies taken from the MaNGA survey. We show that the star formation rate surface density (Sigma_SFR), derived based on the H_alpha emissions, is strongly correlated with the M_star surface density (Sigma_star) on kpc scales for star- forming galaxies and can be directly connected to the global star-forming sequence. This suggests that the global main sequence may be a consequence of a more fundamental relation on small scales. On the other hand, our result suggests that about 20% of quiescent galaxies in our sample still have star formation activities in the outer region with lower SSFR than typical star-forming galaxies. Meanwhile, we also find a tight correlation between Sigma_H_alpha and Sigma_star for LI(N)ER regions, named the resolved "LI(N)ER" sequence, in quiescent galaxies, which is consistent with the scenario that LI(N)ER emissions are primarily powered by the hot, evolved stars as suggested in the literature., Comment: 6 pages, 4 figures. ApJ Letter accepted