A survey of users of earth resources remote sensing data

The results of a NASA supported Battelle survey to obtain user views on the nature and value of LANDSAT data use, on current LANDSAT capabilities, and on ways to improve data use were summarized. Questionnaire and interview responses from over 1000 private and public sector users were analyzed and discussed

Detection of weak lensing by a cluster of galaxies at z=0.83

We report the detection of weak gravitational lensing of faint, distant background galaxies by the rich, X-ray luminous cluster of galaxies MS1054-03 at z=0.83. This is the first measurement of weak lensing by a bona fide cluster at such a high redshift. We detect tangential shear at the 5% - 10% level over a range of radii 50'' < r < 250'' centered on the optical position of the cluster. Two-dimensional mass reconstruction using galaxies with 21.5 < I < 25.5 shows a strong peak which coincides with the peak of the smoothed cluster light distribution. Splitting this sample by magnitude (at I = 23.5) and color (at R-I = 0.7), we find that the brighter and redder subsamples are only very weakly distorted, indicating that the faint blue galaxies (FBG's), which dominate the shear signal, are relatively more distant. The derived cluster mass is quite sensitive to the N(z) for the FBG's. At one extreme, if all the FBG's are at z_s = 3, then the mass within a $0.5h^{-1}$Mpc aperture is $(5.9 \pm 1.24)\times 10^{14}$\h1 $M_\odot$, and the mass-to-light ratio is $M/L_V = 350 \pm 70 h$ in solar units. For $z_s = 1.5$ the derived mass is $\sim$70\% higher and $M/L \simeq 580 h$. If $N(z)$ follows the no evolution model (in shape) then $M/L \simeq 800h$, and if all the FBG's lie at z_s\la 1 the required $M/L$ exceeds $1600h$. These data provide clear evidence that large, dense mass concentrations existed at early epochs; that they can be weighed efficiently by weak lensing observations; and that most of the FBG's are at high redshift.Comment: Submitted to ApJ, 15 pages (incl 8 figs, 3 of which are plates). Plate images not included, but are available from ftp://hubble.ifa.hawaii.edu/pub/ger/ms1054/ms1054_fig[1,3,5].ps.

Weak Lensing Detection of Cl 1604+4304 at z = 0.90

We present a weak lensing analysis of the high-redshift cluster Cl 1604+4304. At z=0.90, this is the highest-redshift cluster yet detected with weak lensing. It is also one of a sample of high-redshift, optically-selected clusters whose X-ray temperatures are lower than expected based on their velocity dispersions. Both the gas temperature and galaxy velocity dispersion are proxies for its mass, which can be determined more directly by a lensing analysis. Modeling the cluster as a singular isothermal sphere, we find that the mass contained within projected radius R is 3.69+-1.47 * (R/500 kpc) 10^14 M_odot. This corresponds to an inferred velocity dispersion of 1004+-199 km/s, which agrees well with the measured velocity dispersion of 989+98-76 km/s (Gal & Lubin 2004). These numbers are higher than the 575+110-85 km/s inferred from Cl 1604+4304 X-ray temperature, however all three velocity dispersion estimates are consistent within ~ 1.9 sigma.Comment: Revised version accepted for publication in AJ (January 2005). 2 added figures (6 figures total

Survey of users of earth resources remote sensing data

A user survey was conducted to determine current earth resources survey (ERS) data use/user status and recommendations for strengthening use. Only high-altitude aircraft and satellite (primarily LANDSAT) data were included. Emphasis was placed on the private sector/industrial user. Objectives of the survey included: who is using ERS data, how they are using the data, the relative value of current data use as well as obtaining user views as to possible ways of strengthening future ERS data use. The survey results are documented and should provide relevant decision making information for developing future programs of maximum benefit to all end users of satellite ERS data

A CFH12k lensing survey of X-ray luminous galaxy clusters. II. Weak lensing analysis and global correlations

Aims. We present a wide-field multi-color survey of a homogeneous sample of eleven clusters of galaxies for which we measure total masses and mass distributions from weak lensing. This sample, spanning a small range in both X-ray luminosity and redshift, is ideally suited to determining the normalisation of scaling relations between X-ray properties of clusters and their masses (the M − T_X and the M − L_X relations) and also estimating the scatter in these relations at a fixed luminosity. Methods. The eleven clusters in our sample are all X-ray luminous and span a narrow redshift range at z = 0.21 ± 0.04. The weak lensing analysis of the sample is based on ground-based wide-field imaging obtained with the CFH12k camera on CFHT. We use the methodology developed and applied previously on the massive cluster Abell 1689. A Bayesian method, implemented in the Im2shape software, is used to fit the shape parameters of the faint background galaxies and to correct for PSF smearing. A multi-color selection of the background galaxies is applied to retrieve the weak lensing signal, resulting in a background density of sources of ~10 galaxies per square arc minute. With the present data, shear profiles are measured in all clusters out to at least 2 Mpc (more than 15 from the center) with high confidence. The radial shear profiles are fitted with different parametric mass profiles and the virial mass M_(200) is estimated for each cluster and then compared to other physical properties. Results. Scaling relations between mass and optical luminosity indicate an increase of the M/L ratio with luminosity (M/L ∝ L^(0.8)) and a LX−M_(200) relation scaling as L_X ∝ M^(0.83±0.11)_(200) while the normalization of the M_(200) ∝ T^(3/2)_X relation is close to the one expected from hydrodynamical simulations of cluster formation as well as previous X-ray analyses. We suggest that the dispersion in the M_(200) − T_X and M_(200) − L_X relations reflects the different merging and dynamical histories for clusters of similar X-ray luminosities and intrinsic variations in their measured masses. Improved statistics of clusters over a wider mass range are required for a better control of the intrinsic scatter in scaling relations

Early-type Galaxies in the Cluster Abell 2390 at z=0.23

To examine the evolution of the early-type galaxy population in the rich cluster Abell 2390 at z=0.23 we have gained spectroscopic data of 51 elliptical and lenticular galaxies with MOSCA at the 3.5 m telescope on Calar Alto Observatory. This investigation spans both a broad range in luminosity (-19.3>M_B>-22.3) and uses a wide field of view of 10'x10', therefore the environmental dependence of different formation scenarios can be analysed in detail as a function of radius from the cluster centre. Here we present results on the surface brightness modelling of galaxies where morphological and structural information is available in the F814W filter aboard the Hubble Space Telescope (HST) and investigate for this subsample the evolution of the Fundamental Plane.Comment: 5 pages, 5 figures, to appear in "Carnegie Observatories Astrophysics Series, Vol. 3: Clusters of Galaxies: Probes of Cosmological Structure and Galaxy Evolution", ed. J. S. Mulchaey, A. Dressler, and A. Oemler (Pasadena: Carnegie Observatories, http://www.ociw.edu/ociw/symposia/series/symposium3/proceedings.html

Evolution in the Clustering of Galaxies to r = 26 (TAPIR GRP-390)

We present results for the two-point angular correlation function of galaxies to a limiting magnitude of r=26. The final sample is 97% complete to r=26.0, yielding 5730 galaxies over a 90.1 sq. arcmin field. The correlation function for our faint galaxies can be parameterised by a power law, $A \theta^{-0.8}$, in agreement with the clustering statistics of shallower catalogues. The derived amplitude, $A$, is small, but non-zero. We combine this measurement with the latest statistical constraints on faint galaxy redshifts from gravitational lensing studies, which imply that the bulk of the r<26 field galaxies should be at redshifts of order 1. Our derived $A$ is significantly lower than that predicted from the local bright galaxy correlation function using the lensing-determined galaxy redshift distribution and modest growth of clustering. This simplistic model does not include the variation in observed morphological mix as a function of redshift and apparent magnitude in our sample. At our faintest limits we reach sufficiently high redshifts that differential $K$ corrections will result in the observed galaxy mix being dominated by star bursting dwarf and low surface brightness irregulars, rather than the early-type systems used to define the local bright galaxy correlation function. Adopting the correlation function measured locally for these low surface brightness galaxies and assuming modest clustering evolution, we obtain reasonable agreement between our model and observations. This model supports the scenario in which the high number density of faint galaxies is produced by normally clustered star forming dwarf galaxies at modest redshifts.Comment: 13 pages LaTeX (article style), 3 figures (tar compressed and uuencoded using uufiles csh script) PostScript figures available via anonymous ftp from goldie.tapir.caltech.edu in directory pub/Roger (files wtheta1.ps, wtheta2.ps, wtheta3.ps

Utilizing Skylab data in on-going resources management programs in the state of Ohio

The author has identified the following significant results. The use of Skylab imagery for total area woodland surveys was found to be more accurate and cheaper than conventional surveys using aerial photo-plot techniques. Machine-aided (primarily density slicing) analyses of Skylab 190A and 190B color and infrared color photography demonstrated the feasibility of using such data for differentiating major timber classes including pines, hardwoods, mixed, cut, and brushland providing such analyses are made at scales of 1:24,000 and larger. Manual and machine-assisted image analysis indicated that spectral and spatial capabilities of Skylab EREP photography are adequate to distinguish most parameters of current, coal surface mining concern associated with: (1) active mining, (2) orphan lands, (3) reclaimed lands, and (4) active reclamation. Excellent results were achieved when comparing Skylab and aerial photographic interpretations of detailed surface mining features. Skylab photographs when combined with other data bases (e.g., census, agricultural land productivity, and transportation networks), provide a comprehensive, meaningful, and integrated view of major elements involved in the urbanization/encroachment process

Shapes and Shears, Stars and Smears: Optimal Measurements for Weak Lensing

We present the theoretical and analytical bases of optimal techniques to measure weak gravitational shear from images of galaxies. We first characterize the geometric space of shears and ellipticity, then use this geometric interpretation to analyse images. The steps of this analysis include: measurement of object shapes on images, combining measurements of a given galaxy on different images, estimating the underlying shear from an ensemble of galaxy shapes, and compensating for the systematic effects of image distortion, bias from PSF asymmetries, and `"dilution" of the signal by the seeing. These methods minimize the ellipticity measurement noise, provide calculable shear uncertainty estimates, and allow removal of systematic contamination by PSF effects to arbitrary precision. Galaxy images and PSFs are decomposed into a family of orthogonal 2d Gaussian-based functions, making the PSF correction and shape measurement relatively straightforward and computationally efficient. We also discuss sources of noise-induced bias in weak lensing measurements and provide a solution for these and previously identified biases.Comment: Version accepted to AJ. Minor fixes, plus a simpler method of shape weighting. Version with full vector figures available via http://www.astro.lsa.umich.edu/users/garyb/PUBLICATIONS