We present the C4 Cluster Catalog, a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers $2600 deg 2 of sky and ranges in redshift from z ¼ 0:02 to 0.17. The mean cluster membership is 36 galaxies (with measured redshifts) brighter than r ¼ 17:7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L r ), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the ÃCDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands, and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is '90% complete and 95% pure above M 200 ¼ 1 ; 10 14 h À1 M and within 0:03 z 0:12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray-identified clusters and 90% of Abell clusters within 0:03 z 0:12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L r of a cluster is a more robust estimator of the halo mass (M 200 ) than the galaxy line-of-sight velocity dispersion or the richness of the cluster. However, if we exclude clusters embedded in complex large-scale environments, we find that the velocity dispersion of the remaining clusters is as good an estimator of M 200 as L r . The final C4 catalog will contain '2500 clusters using the full SDSS data set and will represent one of the largest and most homogeneous samples of local clusters.

We present UFTI K‐band imaging observations of 222 galaxies that are selected from the Sloan Digital Sky Survey to have unusually strong Hδ absorption equivalent widths, W○(Hδ) > 4 Å. Using gim2d, the images are fitted with two‐dimensional surface‐brightness models consisting of a simple disc and bulge component to derive the fraction of luminosity in the bulge B/T. We find that the galaxies with weak or absent Hα or [O ii]λ3727 emission (known as k+a galaxies) are predominantly bulge‐dominated (with a mode of B/T∼ 0.6), while galaxies with nebular emission [known as e(a) galaxies] are mostly disc‐dominated (B/T∼ 0.1). The morphologies and (r−k) colours of most k+a galaxies are inconsistent with the hypothesis that they result from the truncation of star formation in normal, spiral galaxies. However, their (u−g) and (r−k) colours, as well as their Hδ line strengths, form a sequence that is well matched by a model in which >5 per cent of the stellar mass has been produced in a recent starburst. The lack of scatter in the dust‐sensitive (r−k) colours suggests that the unusual spectra of k+a galaxies are not due to the effects of dust. The e(a) galaxies, on the other hand, have a colour distribution that is distinct from the k+a population, and typical of normal or dusty (τV∼ 2) spiral galaxies. We conclude that many e(a) galaxies are not progenitors of k+a galaxies, but are a separate phenomenon. Both k+a and e(a) galaxies reside in environments (characterized by the local density of galaxies brighter than Mr=−20) that are typical of normal galaxies and that are inconsistent with overdense regions like rich galaxy clusters.

Context. We present the revised near-to mid-infrared catalogue of the AKARI North Ecliptic Pole deep survey. The survey has the unique advantage of continuous filter coverage from 2 to 24 μm over nine photometric bands, but the initial version of the survey catalogue leaves room for improvement in the image analysis stage; the original images are strongly contaminated by the behaviour of the detector and the optical system. Aims. The purpose of this study is to devise new image analysis methods and to improve the detection limit and reliability of the source extraction. Methods. We removed the scattered light and stray light from the Earth limb, and corrected for artificial patterns in the images by creating appropriate templates. We also removed any artificial sources due to bright sources by using their properties or masked them out visually. In addition, for the mid-infrared source extraction, we created detection images by stacking all six bands. This reduced the sky noise and enabled us to detect fainter sources more reliably. For the near-infrared source catalogue, we considered only objects with counterparts from ground-based catalogues to avoid fake sources. For our ground-based catalogues, we used catalogues based on the CFHT/MegaCam z band, CFHT/WIRCam Ks band and Subaru/Scam z band. Objects with multiple counterparts were all listed in the catalogue with a merged flag for the AKARI flux. Results. The detection limits of all mid-infrared bands were improved by ∼20%, and the total number of detected objects was increased by ∼2000 compared with the previous version of the catalogue; it now has 9560 objects. The 5σ detection limits in our catalogue are 11, 9, 10, 30, 34, 57, 87, 93, and 256 μJy in the N2, N3, N4, S7, S9W, S11, L15, L18W, and L24 bands, respectively. The astrometric accuracies of these band detections are 0.48, 0.52, 0.55, 0.99, 0.95, 1.1, 1.2, 1.3, and 1.6 arcsec, respectively. The false-detection rate of all nine bands was decreased to less than 0.3%. In total, 27 770 objects are listed in the catalogue, 11 349 of which have mid-infrared fluxes.

This pilot study suggests that FLIR ONE can work as an alternative device for assessing subclinical inflammation in PUs and the diabetic foot in clinical settings. Our results may facilitate clinicians in accepting the routine use of thermal imaging assessment at the patients' bedside.

We present a new catalogue of mid-IR sources using the AKARI NEP-Deep survey. The InfraRed Camera (IRC) onboard AKARI has a comprehensive mid-IR wavelength coverage with 9 photometric bands at 2-24 μm. We utilized all of these bands to cover a nearly circular area adjacent to the north ecliptic pole (NEP). We designed the catalogue to include most of sources detected in 7, 9, 11, 15 and 18 μm bands, and found 7284 sources in a 0.67 deg 2 area. From our simulations, we estimate that the catalogue is ∼80 per cent complete to 200 μJy at 15-18 μm, and ∼10 per cent of sources are missed, owing to source blending. Star-galaxy separation is conducted using only AKARI photometry, as a result of which 10 per cent of catalogued sources are found to be stars. The number counts at 11, 15, 18, and 24 μm are presented for both stars and galaxies. A drastic increase in the source density is found in between 11 and 15 μm at the flux level of ∼300 μJy. This is likely due to the redshifted PAH emission at 8 μm, given our rough estimate of redshifts from an AKARI colour-colour plot. Along with the mid-IR source catalogue, we present optical-NIR photometry for sources falling inside a Subaru/Sprime-cam image covering part of the AKARI NEP-Deep field, which is deep enough to detect most of AKARI mid-IR sources, and useful to study optical characteristics of a complete mid-IR source sample.