Rich Clusters Research Articles

Dependence of magnetic properties on the growth temperature of Mn0.04Ge0.96 grown on Si (001)

The structural and magnetic properties of Mn 0.04 Ge 0.96 thin films grown on Si (001) substrates at different growth temperatures were investigated. The films were grown by sequential deposition of MnGe and Ge multilayers using molecular beam epitaxy . It was found that the magnetic ordering and Curie temperature could be controlled by adjusting the distance between the Mn ions in the Ge spacer layer depending on growth temperature. We found that the samples grown below 130 °C contained highly disordered ferromagnetic Mn rich domains. Both structural and magnetic characterizations revealed that Mn 5 Ge 3 precipitates were formed in Mn clusters free Ge matrix when the samples were grown at 150 °C. Both the Mn rich domains and Mn 5 Ge 3 precipitates showed out of the plane magnetic anisotropy and similar ESR line shapes. • We investigated the effects of growth temperature on spin systems in Mn 0.04 Ge 0.96 . • The degree of ferromagnetic ordering increases with temperature. • Ferromagnetism occurs due to interaction of Mn 2+ ions in Mn rich clusters. • ESR reveals that the formation of magnetic phases depends on growth temperature.

A NEW METHOD TO SEARCH FOR HIGH-REDSHIFT CLUSTERS USING PHOTOMETRIC REDSHIFTS

We describe a new method (Poisson Probability Method, PPM) to search for high redshift galaxy clusters and groups by using photometric redshift information and galaxy number counts. The method relies on Poisson statistics and is primarily introduced to search for Mpc-scale environments around a specific beacon. The PPM is tailored to both the properties of the FR I radio galaxies in the Chiaberge et al. (2009) sample, that are selected within the COSMOS survey, and on the specific dataset used. We test the efficiency of our method of searching for cluster candidates against simulations. Two different approaches are adopted. i) We use two z~1 X-ray detected cluster candidates found in the COSMOS survey and we shift them to higher redshift up to z=2. We find that the PPM detects the cluster candidates up to z=1.5, and it correctly estimates both the redshift and size of the two clusters. ii) We simulate spherically symmetric clusters of different size and richness, and we locate them at different redshifts (i.e. z = 1.0,1.5, and 2.0) in the COSMOS field. We find that the PPM detects the simulated clusters within the considered redshift range with a statistical 1-sigma redshift accuracy of ~0.05. The PPM is an efficient alternative method for high-redshift cluster searches that may also be applied to both present and future wide field surveys such as SDSS Stripe 82, LSST, and Euclid. Accurate photometric redshifts and a survey depth similar or better than that of COSMOS (e.g. I<25) are required.

CLUSTER CANDIDATES AROUND LOW-POWER RADIO GALAXIES ATz∼ 1-2 IN COSMOS

We search for high redshift ($z\sim$1-2) galaxy clusters using low luminosity radio galaxies (FR~I) as beacons and our newly developed Poisson Probability Method (PPM) based on photometric redshift information and galaxy number counts. We use a sample of 32 FR~Is within the Cosmic Evolution Survey (COSMOS) field from Chiaberge et al. (2009) catalog. We derive a reliable subsample of 21 {\it bona fide} Low Luminosity Radio Galaxies (LLRGs) and a subsample of 11 High Luminosity Radio Galaxies (HLRGs), on the basis of photometric redshift information and NRAO VLA Sky Survey (NVSS) radio fluxes. The LLRGs are selected to have 1.4~GHz rest frame luminosities lower than the fiducial FR~I/FR~II divide. This also allows us to estimate the comoving space density of sources with $L_{1.4}\simeq 10^{32.3}\,\hbox{erg}\,\hbox{s}^{-1}\,\hbox{Hz}^{-1}$ at $z\simeq 1.1$, which strengthens the case for a strong cosmological evolution of these sources. In the fields of the LLRGs and HLRGs we find evidence that 14 and 8 of them reside in rich groups or galaxy clusters, respectively. Thus, overdensities are found around $\sim70\%$ of the FR~Is, independently of the considered subsample. This rate is in agreement with the fraction found for low redshift FR~Is and it is significantly higher than that of FR~IIs at all redshifts. Although our method is primarily introduced for the COSMOS survey, it may be applied to both present and future wide field surveys such as SDSS Stripe 82, LSST, and Euclid. Furthermore, cluster candidates found with our method are excellent targets for next generation space telescopes such as JWST.

Orientation bias of optically selected galaxy clusters and its impact on stacked weak-lensing analyses

Weak-lensing measurements of the averaged shear profiles of galaxy clusters binned by some proxy for cluster mass are commonly converted to cluster mass estimates under the assumption that these cluster stacks have spherical symmetry. In this paper we test whether this assumption holds for optically selected clusters binned by estimated optical richness. Using mock catalogues created from N-body simulations populated realistically with galaxies, we ran a suite of optical cluster finders and estimated their optical richness. We binned galaxy clusters by true cluster mass and estimated optical richness and measure the ellipticity of these stacks. We find that the processes of optical cluster selection and richness estimation are biased, leading to stacked structures that are elongated along the line-of-sight. We show that weak-lensing alone cannot measure the size of this orientation bias. Weak lensing masses of stacked optically selected clusters are overestimated by up to 3-6 per cent when clusters can be uniquely associated with haloes. This effect is large enough to lead to significant biases in the cosmological parameters derived from large surveys like the Dark Energy Survey, if not calibrated via simulations or fitted simultaneously. This bias probably also contributes to the observed discrepancy between the observed and predicted Sunyaev-Zel'dovich signal of optically-selected clusters.

WIYN OPEN CLUSTER STUDY. LX. SPECTROSCOPIC BINARY ORBITS IN NGC 6819

We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8,000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1-degree field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main-sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10,000 days to be 22% +/- 3% and a tidal circularization period of 6.2 +/- 1.1 days for NGC 6819.

Discovery of an overlapping cluster in the Abell 1674 field with Suzaku

Abstract We present the results of a Suzaku observation of Abell 1674, an optically very rich (richness class 3) cluster cataloged as z = 0.1066. We discover the He-like Fe K-shell line from the central region for the first time, and find that the X-ray spectrum yields a high redshift of $0.215^{+0.007}_{-0.006}$. On the other hand, the spectrum of the south-western region is fitted with a redshift of 0.11 ± 0.02 by the He-like Fe L-shell lines, consistent with the optically determined value. The gas temperature, metal abundance, and core radius of the X-ray emission in the central region are 3.8 ± 0.2 keV, 0.20 ± 0.05 Z⊙, and 450 ± 40 kpc, respectively, while those in the south-western region are 2.0 ± 0.2 keV, $0.41^{+0.17}_{-0.13}\,Z$⊙, and $220^{+90}_{-70}$ kpc, respectively. These parameters are typical for clusters. We thus conclude that Abell 1674 consists of two independent clusters, A 1674-C at z ∼ 0.22 and A 1674-SW at z ∼ 0.11, overlapping along the line of sight. The X-ray luminosity of A 1674-C within r = 2 Mpc is (15.9 ± 0.6) × 1043 erg s−1 in the 0.1–2.4 keV energy band, while that for A 1674-SW is (1.25 ± 0.07) × 1043 erg s−1. Both are consistent with those expected from the L–T relation of clusters within a factor of 2. This is another supporting factor for our conclusion.

A complete, multi-level conformational clustering of antibody complementarity-determining regions.

Classification of antibody complementarity-determining region (CDR) conformations is an important step that drives antibody modelling and engineering, prediction from sequence, directed mutagenesis and induced-fit studies, and allows inferences on sequence-to-structure relations. Most of the previous work performed conformational clustering on a reduced set of structures or after application of various structure pre-filtering criteria. In this study, it was judged that a clustering of every available CDR conformation would produce a complete and redundant repertoire, increase the number of sequence examples and allow better decisions on structure validity in the future. In order to cope with the potential increase in data noise, a first-level statistical clustering was performed using structure superposition Root-Mean-Square Deviation (RMSD) as a distance-criterion, coupled with second- and third-level clustering that employed Ramachandran regions for a deeper qualitative classification. The classification of a total of 12,712 CDR conformations is thus presented, along with rich annotation and cluster descriptions, and the results are compared to previous major studies. The present repertoire has procured an improved image of our current CDR Knowledge-Base, with a novel nesting of conformational sensitivity and specificity that can serve as a systematic framework for improved prediction from sequence as well as a number of future studies that would aid in knowledge-based antibody engineering such as humanisation.

X-ray AGN in the XMM-LSS galaxy clusters: no evidence of AGN suppression

We present a study of the overdensity of X-ray selected AGN in 33 galaxy clusters in the XMM-LSS field, up to redhift z=1.05. Previous studies have shown that the presence of X-ray selected AGN in rich galaxy clusters is suppressed. In the current study we investigate the occurrence of X-ray selected AGN in low and moderate X-ray luminosity galaxy clusters. Due to the wide contiguous XMM-LSS survey area we are able to extend the study to the cluster outskirts. We therefore determine the projected overdensity of X-ray point-like sources out to 6r_{500} radius. To provide robust statistical results we also use a stacking analysis of the cluster projected overdensities. We investigate whether the observed X-ray overdensities are to be expected by estimating also the corresponding optical galaxy overdensities. We find a positive X-ray projected overdensity at the first radial bin, which is however of the same amplitude as that of optical galaxies. Therefore, no suppression of X-ray AGN activity with respect to the field is found, implying that the mechanisms responsible for the suppression are not so effective in lower density environments. After a drop to roughly the background level between 2 and 3r_{500}, the X-ray overdensity exhibits a rise at larger radii, significantly larger than the corresponding optical overdensity. Finally, using redshift information of all optical counterparts, we derive the spatial overdensity profile of the clusters. We find that the agreement between X-ray and optical overdensities in the first radial bin is also suggested in the 3-dimensional analysis. However, we argue that the X-ray overdensity "bump" at larger radial distance is probably a result of flux boosting by gravitational lensing of background QSOs. For high redshift clusters an enhancement of X-ray AGN activity in their outskirts is still possible.

THE ACTIVE GALACTIC NUCLEUS POPULATION IN X-RAY-SELECTED GALAXY GROUPS AT 0.5 &lt;Z&lt; 1.1

We use Chandra data to study the incidence and properties of Active Galactic Nuclei (AGN) in 16 intermediate redshift ($0.5 < z < 1.1$) X-ray-selected galaxy groups in the Chandra Deep Field-South. We measure an AGN fraction of $f(L_{X,H} > 10^{42}; M_R<-20) = 8.0_{-2.3}^{+3.0}\%$ at $\bar{z} \sim 0.74$, approximately a factor of two higher than the AGN fraction found for rich clusters at comparable redshift. This extends the trend found at low redshift for groups to have higher AGN fractions than clusters. Our estimate of the AGN fraction is also more than a factor of 3 higher than that of low redshift X-ray-selected groups. Using optical spectra from various surveys, we also constrain the properties of emission-line selected AGN in these groups. Contrary to the large population of X-ray AGN ($N(L_{X,H} > 10^{41}$ erg/s) = 25), we find only 4 emission-line AGN, 3 of which are also X-ray bright. Furthermore, most of the X-ray AGN in our groups are optically-dull (i.e. lack strong emission-lines) similar to those found in low redshift X-ray groups and clusters of galaxies. This contrasts with the AGN population found in low redshift optically-selected groups which are dominated by emission-line AGN. The differences between the optically and X-ray-selected AGN populations in groups are consistent with a scenario where most AGN in the densest environments are currently in a low accretion state.

Synthesis and characterization of Ag-Co-Ni nanowires.

This work provides an electrodeposition-based methodology for synthesizing multicomponent nanowires containing Ag, Co and Ni atoms. Nanowire morphology was obtained by using an anodic alumina membrane with cylindrical pores of ∼ 200-nm diameter. Structural, compositional and magnetic characterization revealed that the as-synthesized nanowires adopted a core-shell microstructure. The core (axial region) contained pure Ag phase volumes with a plate-like morphology oriented perpendicular to the nanowire axis. The shell (peripheral region) contained pure Ag nanoparticles along with superparamagnetic Co and Ni rich clusters.

THE INSIDE-OUT GROWTH OF THE MOST MASSIVE GALAXIES AT 0.3 &lt;z&lt; 0.9

We study the surface brightness profiles of a sample of brightest cluster galaxies (BCGs) with 0.3<z<0.9. The BCGs are selected from the first Red-sequence Cluster Survey and an X-ray cluster survey. The surface brightness profiles of the BCGs are measured using HST ACS images, and most of them can be well modeled by a Sersic profile with index ~ 6 and half-light radius ~ 30 kpc. Although the single Sersic model fits the profiles well, we argue that the systematics in the sky background measurement and the coupling between the model parameters make the comparison of the model parameters ambiguous. Direct comparison of the BCG profiles, on the other hand, has revealed an inside-out growth for these most massive galaxies: as the mass of a BCG increases, the central mass density of the galaxy increases slowly ($\rho_{1kpc} \propto M*^{0.39}$), while the slope of the outer profile grows continuously shallower ($\alpha \propto M*^{-2.5}$). Such a fashion of growth continues down to the less massive early-type galaxies (ETGs), without apparent distinction between BCGs and non-BCGs. For the very massive ETGs and BCGs, the slope of the Kormendy relation starts to trace the slope of the surface brightness profiles and becomes insensitive to subtle profile evolution. These results are generally consistent with dry mergers being the major driver of the mass growth for BCGs and massive ETGs. We also find strong correlations between the richness of clusters and the properties of BCGs: the more massive the clusters are, the more massive the BCGs ($M*_{bcg} \propto M_{clusters}^{0.6}$) and the shallower their surface brightness profiles. After taking into account the bias in the cluster samples, we find the masses of the BCGs have grown by at least a factor of 1.5 from z=0.5 to z=0, in contrast to the previous findings of no evolution. Such an evolution validates the expectation from the LCDM model.

THE ENVIRONMENTAL IMPACTS ON THE STAR FORMATION MAIN SEQUENCE: AN Hα STUDY OF THE NEWLY DISCOVERED RICH CLUSTER ATz= 1.52

We report the discovery of a strong over-density of galaxies in the field of a radio galaxy at z=1.52 (4C65.22) based on our broad-band and narrow-band (H-alpha) photometry with Subaru Telescope. We find that H-alpha emitters are located in the outskirts of the density peak (cluster core) dominated by passive red-sequence galaxies. This resembles the situation in lower-redshift clusters, suggesting that the newly discovered structure is a well-evolved rich galaxy cluster at z=1.5. Our data suggest that the color-density and stellar mass-density relations are already in place at z~1.5, mostly driven by the passive red massive galaxies residing within Rc<200 kpc from the cluster core. These environmental trends almost disappear when we consider only star-forming (SF) galaxies. We do not find SFR-density or SSFR-density relations amongst SF galaxies, and the location of the SF main sequence does not significantly change with environment. Nevertheless, we find a tentative hint that star-bursting galaxies (up-scattered objects from the main sequence) are preferentially located in a small group at ~1-Mpc away from the main body of the cluster. We also argue that the scatter of the SF main sequence could be dependent on the distance to the nearest neighboring galaxy.

The Adopted Morphological Types of 247 Rich PF Galaxy Clusters

AbstractMorphological types were determined for 247 rich galaxy clusters from the PF Catalogue of Galaxy Clusters and Groups. The adopted types are based on classical morphological schemes and consider concentration to the cluster center, the signs of preferential direction or plane in the cluster, and the positions of the brightest galaxies. It is shown that both concentration and preferential plane are significant and independent morphological criteria.

SPECTROSCOPIC CONFIRMATION OF THE RICHz= 1.80 GALAXY CLUSTER JKCS 041 USING THE WFC3 GRISM: ENVIRONMENTAL TRENDS IN THE AGES AND STRUCTURE OF QUIESCENT GALAXIES

We present Hubble Space Telescope imaging and grism spectroscopy in the field of the distant galaxy cluster JKCS 041 using the Wide Field Camera 3. We confirm that JKCS 041 is a rich cluster and derive a redshift z=1.80 via the spectroscopic identification of 19 member galaxies, of which 15 are quiescent. These are centered upon diffuse X-ray emission seen by the Chandra observatory. As JKCS 041 is the most distant known cluster with such a large, spectroscopically confirmed quiescent population, it provides a unique opportunity to study the effect of the environment on galaxy properties at early epochs. We construct high-quality composite spectra of the quiescent cluster members that reveal prominent Balmer and metallic absorption lines. Using these, we measure the mean stellar ages in two bins of stellar mass. The quiescent cluster members' ages agree remarkably closely with that inferred by Whitaker et al. for similarly selected samples in the field, supporting the idea that the cluster environment is more efficient at truncating star formation while not having a strong effect on the mean epoch of quenching. We find some evidence (90% confidence) for a lower fraction of disk-like quiescent systems in JKCS 041 compared to a sample of coeval field galaxies drawn from the CANDELS survey. Taking this into account, we do not detect a significant difference between the mass-radius relations of the quiescent JKCS 041 members and our z~1.8 field sample. Finally, we demonstrate how differences in the morphological mixture of quenched systems can complicate measures of the environmental dependence of size growth.

CORE-HALO AGE GRADIENTS AND STAR FORMATION IN THE ORION NEBULA AND NGC 2024 YOUNG STELLAR CLUSTERS

We analyze age distributions of two nearby rich stellar clusters, the NGC 2024 (Flame Nebula) and Orion Nebula Cluster (ONC) in the Orion molecular cloud complex. Our analysis is based on samples from the MYStIX survey and a new estimator of pre-main sequence (PMS) stellar ages, AgeJX, derived from X-ray and near-infrared photometric data. To overcome the problem of uncertain individual ages and large spreads of age distributions for entire clusters, we compute median ages and their confidence intervals of stellar samples within annular subregions of the clusters. We find core-halo age gradients in both the NGC 2024 cluster and ONC: PMS stars in cluster cores appear younger and thus were formed later than PMS stars in cluster peripheries. These findings are further supported by the spatial gradients in the disk fraction and K-band excess frequency. Our age analysis is based on AgeJX estimates for PMS stars, and is independent of any consideration of OB stars. The result has important implications for the formation of young stellar clusters. One basic implication is that clusters form slowly and the apparent age spreads in young stellar clusters, which are often controversial, are (at least in part) real. The result further implies that simple models where clusters form inside-out are incorrect, and more complex models are needed. We provide several star formation scenarios that alone or in combination may lead to the observed core-halo age gradients.

Observational tests of nonlocal gravity: Galaxy rotation curves and clusters of galaxies

A classical nonlocal generalization of Einstein's theory of gravitation has recently been developed via the introduction of a scalar causal "constitutive" kernel that must ultimately be determined from observational data. It turns out that the nonlocal aspect of gravity in this theory can simulate dark matter; indeed, in the Newtonian regime of nonlocal gravity, we recover the phenomenological Tohline-Kuhn approach to modified gravity. A simple generalization of the Kuhn kernel in the context of nonlocal general relativity leads to a two-parameter modified Newtonian force law that involves an additional repulsive Yukawa-type interaction. We determine the parameters of our nonlocal kernel by comparing the predictions of the theory with observational data regarding the rotation curves of spiral galaxies. The best-fitting stellar mass-to-light ratio turns out to be in agreement with astrophysical models; moreover, our results are consistent with the Tully-Fisher relation for spiral galaxies. Light deflection in nonlocal gravity is consistent with general relativity at Solar System scales, while beyond galactic scales an enhanced deflection angle is predicted that is compatible with lensing by the effective "dark matter". Furthermore, we extend our results to the internal dynamics of rich clusters of galaxies and show that the dynamical mass of the cluster obtained from nonlocal gravity is consistent with the measured baryonic mass.

Peculiar radio structures in the central regions of galaxy cluster Abell 585

In this paper we analyze the peculiar radio structure observed across the central region of the galaxy cluster Abell 585 (z=0.12). In the low-resolution radio maps, this structure appears uniform and diffuse on angular scales of ~3 arcmin, and is seemingly related to the distant (z=2.5) radio quasar B3 0727+409 rather than to the cluster itself. However, after a careful investigation of the unpublished archival radio data with better angular resolution, we resolve the structure into two distinct arcmin-scale features, which resemble typical lobes of cluster radio galaxies with no obvious connection to the background quasar. We support this conclusion by examining the spectral and polarization properties of the features, demonstrating in addition that the analyzed structure can hardly be associated with any sort of a radio mini-halo or relics of the cluster. Yet at the same time we are not able to identify host galaxies of the radio lobes in the available optical and infrared surveys. We consider some speculative explanations for our findings, including gravitational wave recoil kicks of SMBHs responsible for the lobes' formation in the process of merging massive ellipticals within the central parts of a rich cluster environment, but we do not reach any robust conclusions regarding the origin of the detected radio features.

JKCS 041: a Coma cluster progenitor atz= 1.803

Using deep two-color near-infrared HST imaging and unbiased grism spectroscopy we present a detailed study of the z=1.803 JKCS041 cluster. Uniquely, for a high redshift cluster, we confirm a mass of $\log M=14.2$ in solar units using four different techniques based on the X-ray temperature, the X-ray luminosity and the cluster richness. JKCS041 is thus a progenitor of a local system like the Coma cluster. Our rich dataset and the abundant population of 14 spectroscopically-confirmed red sequence galaxies allows us to explore the past star formation history of this system in unprecedented detail. Remarkably, we find a prominent red sequence down to stellar masses as low as $\log M=9.8$, corresponding to a mass range of 2 dex. These quiescent galaxies are concentrated around the cluster center with a core radius of 330 kpc. Blue members are few and avoid the cluster center. In JKCS041 quenching was therefore largely completed by a look-back time of 10 Gyr and we can constrain the epoch at which this occurred via spectroscopic age-dating of the individual galaxies. Most galaxies were quenched about 1.1 Gyr prior to the epoch of observation. The less massive quiescent galaxies are somewhat younger, corresponding to a decrease in age of 650 Myr per mass dex, but the scatter in age at fixed mass is only 380 Myr (at $\log M=11$). The size-mass relation of quiescent galaxies in JKCS041 is consistent with that observed for local clusters within our uncertainties. Comparing our data on JKCS041 with 41 clusters at lower redshift, we find that the form of the mass function of red sequence galaxies has hardly evolved in the past 10 Gyr, both in terms of its faint end slope and characteristic mass. Despite observing JKCS041 soon after its quenching and the three fold expected increase in mass in the next 10 Gyr, it is already remarkably similar to present-day clusters.

A NEAR-INFRARED CENSUS OF THE MULTICOMPONENT STELLAR STRUCTURE OF EARLY-TYPE DWARF GALAXIES IN THE VIRGO CLUSTER

The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (-19 < M_r < -16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ~15% of the galaxies), to the galaxy images. While a single S\'ersic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multi-component models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted with S\'ersic n values close to 1. At a given magnitude they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multi-component structures in early-type dwarfs are mostly a phenomenon inherent to the disks, and may indeed stem from environmental processing.

Quenching star formation in cluster galaxies

In order to understand the processes that quench star formation within rich clusters, we construct a library of subhalo orbits drawn from $\Lambda$CDM cosmological N-body simulations of four rich clusters. The orbits are combined with models of star formation followed by quenching in the cluster environment. These are compared with observed bulge and disc colours and stellar absorption linestrength indices of satellite galaxies. Models in which the bulge stellar populations depend only on the galaxy subhalo mass while the disc quenching depends on the cluster environment are acceptable fits to the data. An exponential disc quenching timescale of 3 - 3.5 Gyr is preferred. Models with short ($\lesssim 1$ Gyr) quenching timescales yield cluster-centric gradients in disc colours and Balmer line indices that are too steep compared to observations. We also examine models in which there is quenching in lower mass groups prior to cluster infall ("pre-processing"), finding that such models are a better fit to the data than models without pre-processing and require similar quenching times. The data slightly prefer models where quenching occurs only for galaxies falling within about 0.5 $r_{200}$. Finally, we have examined models with short quenching timescales of 1 Gyr, but a long delay time of 3 Gyr prior to quenching. All models with short quenching timescales, even such "delayed-then-rapid" quenching models, produce excessively red galaxies near the cluster core and are strongly disfavoured by the data. These results imply that the environments of rich clusters must impact star formation rates of infalling galaxies on relatively long timescales -- several times longer than a typical halo spends within the virial radius of a cluster. This scenario favours gentler quenching mechanisms such as slow "strangulation" over more rapid ram-pressure stripping.