- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
<i>Spitzer Planck Herschel</i> Infrared Cluster (SPHerIC) survey: Candidate galaxy clusters at 1.3 < <i>z</i> < 3 selected by high star-formation rate
摘要： There is a lack of large samples of spectroscopically confirmed clusters and protoclusters at high redshifts, z > 1.5. Discovering and characterizing distant (proto-)clusters is important for yielding insights into the formation of large-scale structure and on the physical processes responsible for regulating star-formation in galaxies in dense environments. The Spitzer Planck Herschel Infrared Cluster (SPHerIC) survey was initiated to identify these characteristically faint and dust-reddened sources during the epoch of their early assembly. We present Spitzer/IRAC observations of 82 galaxy (proto-)cluster candidates at 1.3 < zp < 3.0 that were vetted in a two step process: (1) using Planck to select by color those sources with the highest star-formation rates, and (2) using Herschel at higher resolution to separate out the individual red sources. The addition of the Spitzer data enables efficient detection of the central and massive brightest red cluster galaxies (BRCGs). We find that BRCGs are associated with highly significant, extended and crowded regions of IRAC sources which are more overdense than the field. This result corroborates our hypothesis that BRCGs within the Planck–Herschel sources trace some of the densest and actively star-forming proto-clusters in the early Universe. On the basis of a richness-mass proxy relation, we obtain an estimate of their mean masses which suggests our sample consists of some of the most massive clusters at z ≈ 2 and are the likely progenitors of the most massive clusters observed today.
关键词： galaxies: star formation,submillimeter: galaxies,infrared: galaxies,galaxies: evolution,galaxies: clusters: general,galaxies: high-redshift
更新于2025-09-23 15:23:52
-
The PAU Survey: spectral features and galaxy clustering using simulated narrow-band photometry
摘要： We present a mock catalogue for the Physics of the Accelerating Universe Survey (PAUS) and use it to quantify the competitiveness of narrow-band imaging for measuring spectral features and galaxy clustering. The mock agrees with observed number count and redshift distribution data. We demonstrate the importance of including emission lines in the narrow-band fluxes. We show that PAUCam has sufficient resolution to measure the strength of the 4000 ? break to the nominal PAUS depth. We predict the evolution of a narrow-band luminosity function and show how this can be affected by the O II emission line. We introduce new rest-frame broad-bands (UV and blue) that can be derived directly from the narrow-band fluxes. We use these bands along with D4000 and redshift to define galaxy samples and provide predictions for galaxy clustering measurements. We show that systematic errors in the recovery of the projected clustering due to photometric redshift errors in PAUS are significantly smaller than the expected statistical errors. The galaxy clustering on two halo scales can be recovered quantitatively without correction, and all qualitative trends seen in the one halo term are recovered. In this analysis, mixing between samples reduces the expected contrast between the one halo clustering of red and blue galaxies and demonstrates the importance of a mock catalogue for interpreting galaxy clustering results. The mock catalogue is available on request at https://cosmohub.pic.es/home.
关键词： galaxies: evolution,large-scale structure of Universe,galaxies: formation,galaxies: luminosity function, mass function
更新于2025-09-23 15:23:52
-
SDSS J122958.84+000138.0: A compact, optically red galaxy
摘要： We report a new compact galaxy, SDSS J122958.84+000138.0 (SDSS J1229+0001), which has unique morphological and stellar population properties that are rare in observations of the nearby Universe. SDSS J1229+0001 has an r-band absolute magnitude (Mr) and half-light radius (Rh) of ?17.75 mag and 520 pc, respectively. Located in a fairly low-density environment, morphologically it is akin to a typical early-type galaxy as it has a smooth appearance and red colour. However, interestingly, it possesses centrally concentrated star-forming activity with a significant amount of dust. We present an analysis of its structural and stellar population properties using archival images and VLT/FORS2 spectroscopy. An analysis of the UKIDSS H-band image shows that the observed light distribution is better fitted with a two-component Sérsic function with inner and outer component effective radii of 190 and 330 pc, respectively. The overall half-light radius measured in the H band is much smaller compared to optical, i.e. 290 pc. We prepared a spectral energy distribution from optical to far-infrared and interpret it to derive the star-formation rate, dust mass and stellar mass. We find that SDSS J1229+0001 has dust mass Mdust = 5.1 × 10^5 M☉ with a dust-to-stellar mass ratio log(Mdust/M?) = ?3.5. While the observed stellar population properties are – to some extent – like those of a typical S0 galaxy, a unified view from stellar population and structural properties may suggest that SDSS J1229+0001 is a smoking gun example of a compact early-type galaxy in formation.
关键词： galaxies: formation,galaxies: star formation,galaxies: elliptical and lenticular, cD,galaxies: individual: SDSS J122958.84+000138.0,galaxies: evolution,galaxies: dwarf
更新于2025-09-23 15:22:29
-
MASSIV: Mass Assembly Survey with SINFONI in VVDS
摘要： Aims. The MASSIV (Mass Assembly Survey with SINFONI in VVDS) project aims at finding constraints on the different processes involved in galaxy evolution. This study proposes to improve understanding of the galaxy mass assembly through chemical evolution using metallicity as a tracer of the star formation and interaction history. Methods. We analysed the full sample of MASSIV galaxies for which a metallicity estimate has been possible, the 48 star-forming galaxies at z ～ 0.9?1.8, and computed the integrated values of some of the fundamental parameters, such as stellar mass, metallicity, and star formation rate (SFR). The sample of star-forming galaxies at similar redshifts from zCOSMOS was also combined with the MASSIV sample. We studied the cosmic evolution of the mass-metallicty relation, together with the effect of close environment and galaxy kinematics on this relation. We then focussed on the so-called fundamental metallicity relation and other relations between stellar mass, SFR, and metallicity. We investigated whether these relations are really fundamental, i.e. if they do not evolve with redshift. Results. The MASSIV galaxies follow the expected mass-metallicity relation for their median redshift. We find, however, a significant difference between isolated and interacting galaxies as found for local galaxies: interacting galaxies tend to have a lower metallicity. The study of the relation between stellar mass, SFR, and metallicity gives such large scattering for our sample, even combined with zCOSMOS, that it is difficult to confirm any fundamental relation.
关键词： galaxies: abundances,galaxies: high-redshift,galaxies: fundamental parameters,galaxies: evolution
更新于2025-09-23 15:22:29
-
Do cluster properties affect the quenching rate?
摘要： The quenching rate is known to depend on galaxy stellar mass and environment, however, possible dependences on the hosting halo properties, such as mass, richness, and dynamical status, are still debated. The determination of these dependences is hampered by systematics, induced by noisy estimates of cluster mass or by the lack of control on galaxy stellar mass, which may mask existing trends or introduce fake trends. We studied a sample of local clusters (20 with 0.02 < z < 0.1 and log(M200/M(cid:3)) (cid:2) 14), selected independent of the galaxy properties under study, having homogeneous optical photometry and X-ray estimated properties. Using those top quality measurements of cluster mass, hence of cluster scale, richness, iron abundance, and cooling time/presence of a cool-core, we study the simultaneous dependence of quenching on these cluster properties on galaxy stellar mass M and normalised cluster-centric distance r/r200. We found that the quenching rate can be completely described by two variables only, galaxy stellar mass and normalised cluster-centric distance, and is independent of halo properties (mass, richness, iron abundance, and central cooling time/presence of a cool-core). These halo properties change, in most cases, by less than 3% the probability that a galaxy is quenched, once the mass-size (M200 – r200) scaling relation is accounted for through cluster-centric distance normalisation.
关键词： galaxies: star formation,galaxies: evolution,galaxies: clusters: general
更新于2025-09-23 15:22:29
-
Cross-correlation of cosmic far-infrared background anisotropies with large scale structures
摘要： We measure the cross-power spectra between luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS)-III data release 8 (DR8) and cosmic infrared background (CIB) anisotropies from Planck and data from the Improved Reprocessing (IRIS) of the Infrared Astronomical Satellite (IRAS) at 353, 545, 857, and 3000 GHz, corresponding to 850, 550, 350 and 100 μm, respectively, in the multipole range 100 < l < 1000. Using approximately 6.5 × 10^5 photometrically determined LRGs in 7760 deg^2 of the northern hemisphere in the redshift range 0.45 < z < 0.65, we model the far-infrared background (FIRB) anisotropies with an extended version of the halo model. With these methods, we confirm the basic picture obtained from recent analyses of FIRB anisotropies with Herschel and Planck that the most efficient halo mass at hosting star forming galaxies is log(Meff/M☉) = 12.84 ± 0.15. We estimate the percentage of FIRB anisotropies correlated with LRGs as approximately 11.8%, 3.9%, 1.8%, and 1.0% of the total at 3000, 857, 545, and 353 GHz, respectively. At redshift z ～ 0.55, the bias of FIRB galaxies with respect to the dark matter density field has the value bFIRB ～ 1.45, and the mean dust temperature of FIRB galaxies is Td = 26 K. Finally, we discuss the impact of present and upcoming cross-correlations with far-infrared background anisotropies on the determination of the global star formation history and the link between galaxies and dark matter.
关键词： galaxies: statistics,large-scale structure of Universe,galaxies: evolution,cosmic background radiation,infrared: diffuse background
更新于2025-09-23 15:22:29
-
Physical conditions in high? <i>z</i> optically thin C? <scp>iii</scp> absorbers: Origin of cloud sizes and associated correlations
摘要： We present detailed photoionization models of well aligned optically thin C iii absorption components at 2.1 < z < 3.4. Using our models we estimate density (nH), metallicity ([C/H]), total hydrogen column density and line-of-sight thickness (L) in each C iii components. We estimate the systematic errors in these quantities contributed by the allowed range of the quasar spectral index used in the ultraviolet background radiation calculations. Our inferred nH and overdensity (?) are much higher than the measurements available in the literature and favor the absorption originating from gas associated with circumgalactic medium and probably not in hydrostatic equilibrium. We also notice nH, L and [C/H] associated with C iii components show statistically signi?cant redshift evolution. To some extent, these redshift evolutions are driven by the appearance of compact, high nH and high [C/H] components only in the low?z end. We ?nd more than 5σ level correlation between [C/H] and L, L and neutral hydrogen column density (N (H i)), N (H i) and [C/H]. We show L versus [C/H] correlation can be well reproduced if L is governed by the product of gas cooling time and sound speed as expected in the case of cloud fragmentation under thermal instabilities. This allows us to explain other observed correlations by simple photoionization considerations. Studying the optically thin C iii absorbers over a large z range and probably correlating their z evolution with global star formation rate density evolution can shed light into the physics of cold clump formation and their evolution in the circumgalactic medium.
关键词： galaxies: haloes,galaxies : evolution,quasars: absorption lines
更新于2025-09-23 15:22:29
-
Characteristics of mid-infrared PAH emission from star-forming galaxies selected at 250?μm in the North Ecliptic Pole field
摘要： Evolutionary properties of infrared (IR) luminous galaxies are important keys to understand dust-obscured star formation history and galaxy evolution. Based on near- to mid-IR imaging with nine continuous filters of the AKARI space telescope, we present the characteristics of dusty star-forming (SF) galaxies showing polycyclic aromatic hydrocarbon (PAH) features observed by the North Ecliptic Pole (NEP) wide field survey of AKARI and Herschel. All the sample galaxies from the AKARI/NEP-Wide data are selected based both on the Herschel/SPIRE 250 μm detection and optical spectroscopic redshift data. The physical modeling of spectral energy distribution (SED) using all available data points from u* to sub-mm 500 μm band, including WISE and PACS data where available, takes unique advantages of the continuous near- to mid-IR coverage, the reliable constraint on the far-IR peak, and spectroscopically determined accurate redshifts, as well as the energy balance principle by MAGPHYS. This enables us to derive physically meaningful and accurate total infrared luminosity and 8 μm (or PAH) luminosity consistently. Our sample galaxies are in the redshift range z < 1, and the majority of them appear to be normal SF/spiral populations showing PAH features near 8 μm. These SF galaxies showing PAHs in the mid-IR include various types, from quiescent to starbursts. Some of our sample show shortage of 8 μm luminosity compared to the total IR luminosity and this PAH deficit gets severe in more-luminous IR galaxies, suggesting PAH molecules in these galaxies are destroyed by a strong radiation field from the SF region or a large amount of cold dust in the interstellar medium. The specific SFR of our sample shows mass-dependent time evolution which is consistent with a downsizing evolutionary pattern.
关键词： cosmology: observations,galaxies: evolution,infrared: galaxies
更新于2025-09-23 15:22:29
-
The Herschel-PACS North Ecliptic Pole Survey
摘要： A detailed analysis of Herschel/Photoconductor Array Camera and Spectrometer (PACS) observations at the North Ecliptic Pole is presented. High-quality maps, covering an area of 0.44 deg2, are produced and then used to derive potential candidate source lists. A rigorous quality-control pipeline has been used to create ?nal legacy catalogues in the PACS Green 100 μm and Red 160 μm bands, containing 1384 and 630 sources respectively. These catalogues reach to more than twice the depth of the current archival Herschel/PACS Point Source Catalogue, detecting 400 and 270 more sources in the short- and long-wavelength bands, respectively. Galaxy source counts are constructed that extend down to ?ux densities of 6 mJy and 19 mJy (50% completeness) in the Green 100 μm and Red 160 μm bands, respectively. These source counts are consistent with previously published PACS number counts in other ?elds across the sky. The source counts are then compared with a galaxy evolution model which identi?es a population of luminous infrared galaxies as responsible for the bulk of the galaxy evolution over the ?ux range (5–100 mJy) spanned by the observed counts, contributing approximate fractions of 50% and 60% to the cosmic infrared background at 100 μm and 160 μm, respectively.
关键词： galaxies: evolution,surveys
更新于2025-09-23 15:22:29
-
The GALEX Ultraviolet Virgo Cluster Survey (GUViCS)
摘要： We study the role of the environment on galaxy evolution using a sample of 868 galaxies in the Virgo cluster and in its surrounding regions that are selected from the GALEX Ultraviolet Virgo Cluster Survey (GUViCS) with the purpose of understanding the origin of the red sequence in dense environments. The sample spans a wide range in morphological types (from dwarf ellipticals to Im and BCD) and stellar masses (107 (cid:2) Mstar (cid:2) 1011.5 M(cid:3)). We collected multifrequency data covering the whole electromagnetic spectrum for most of the galaxies, including UV, optical, mid- and far-infrared imaging data, as well as optical and HI spectroscopic data. We ?rst identify the di?erent dynamical substructures that compose the Virgo cluster, and we calculate the local density of galaxies using di?erent methods. We then study the distribution of galaxies belonging to the red sequence, the green valley, and the blue cloud within the di?erent cluster substructures or as a function of galaxy density. Our analysis indicates that all the most massive galaxies (Mstar (cid:3) 1011 M(cid:3)) are slow rotators and are the dominant galaxies of the di?erent cluster substructures, which are generally associated with a di?use X-ray emission. They are probably the result of major merging events that occurred at early epochs, as also indicated by their very old stellar populations. Slow rotators of lower stellar mass (108.5 (cid:2) Mstar (cid:2) 1011 M(cid:3)) are also preferentially located within the di?erent high-density substructures of the cluster. Their position in the velocity space indicates that they are virialised within the cluster; thus, they are Virgo members since its formation. They have been shaped by gravitational perturbations occurring within the infalling groups that later form the cluster (pre-processing). On the contrary, low-mass star-forming systems are extremely rare in the inner regions of the Virgo cluster A, where the density of the intergalactic medium is at its maximum. Our ram pressure stripping models consistently indicate that these star-forming systems can be rapidly deprived of their interstellar medium during their interaction with the intergalactic medium. The lack of gas quenches their star-formation activity transforming them into quiescent dwarf ellipticals. This mild transformation does not perturb the kinematic properties of these galaxies, which still have rotation curves typical of star-forming systems.
关键词： galaxies: interactions,galaxies: star formation,galaxies: clusters: general,galaxies: clusters: individual: Virgo,galaxies: ISM,galaxies: evolution
更新于2025-09-23 15:21:21