A deep i-selected multi-waveband galaxy catalogue in the COSMOS field

In this paper we present a deep and homogeneous i-band selected multi-waveband catalogue in the COSMOS field covering an area of about 0.7 square-degree. Our catalogue with a formal 50 percent completeness limit for point sources of i~26.7 comprises about 290.000 galaxies with information in 8 passbands. We combine publicly available u, B, V, r, i, z, and K data with proprietary imaging in H band. We discuss in detail the observations, the data reduction, and the photometric properties of the H-band data. We estimate photometric redshifts for all the galaxies in the catalogue. A comparison with 162 spectroscopic redshifts in the redshift range 0 < z < 3 shows that the achieved accuracy of the photometric redshifts is (Delta_z / (z_spec+1)) ~0.035 with only ~2 percent outliers. We derive absolute UV magnitudes and investigate the evolution of the luminosity function evaluated in the rest-frame UV at 1500 Angstrom. There is a good agreement between the LFs derived here and the LFs derived in the FORS Deep Field. We see a similar brightening of M_star and a decrease of phi_star with redshift. The catalogue including the photometric redshift information is made publicly available.Comment: 20 pages, 17 figures, accepted for publication in MNRAS; high resulution paper: http://www.mpe.mpg.de/~gabasch/COSMOS/cosmos.pd

Observational Test of Environmental Effects on The Local Group Dwarf Spheroidal Galaxies

In this paper, we examine whether tidal forces exerted by the Galaxy or M31 have an influence on the Local Group dwarf spheroidal galaxies (dSphs) which are their companions. We focus on the surface brightness profiles of the dSphs, especially their core radii because it is suggested based on the numerical simulations that tidal disturbance can make core radii extended. We examine the correlation for the dSphs between the distances from their parent galaxy (the Galaxy or M31) and the compactnesses of their surface brightness profiles by using a parameter ``C'' defined newly in this paper. Consequently, we find no significant correlation. We make some remarks on the origin of this result by considering three possible scenarios; tidal picture, dark matter picture, and heterogeneity of the group of dSphs, each of which has been often discussed to understand fundamental properties and formation processes of dSphs.Comment: 14 pages LaTeX, 2 PostScript figures, to appear in ApJ Letter

Seismic response to evolving injection at the Rotokawa geothermal field, New Zealand

Catalogs of microseismicity are routinely compiled at geothermal reservoirs and provide valuable insights into reservoir structure and fluid movement. Hypocentral locations are typically used to infer the orientations of structures and constrain the extent of the permeable reservoir. However, frequency-magnitude distributions may contain additional, and underused, information about the distribution of pressure. Here, we present a four-year catalog of seismicity for the Rotokawa geothermal field in the central Taupō Volcanic Zone, New Zealand starting two years after the commissioning of the 140 MWe Nga Awa Purua power station. Using waveform-correlation-based signal detection we double the size of the previous earthquake catalog, refine the location and orientation of two reservoir faults and identify a new structure. We find the rate of seismicity to be insensitive to major changes in injection strategy during the study period, including the injectivity decline and shift of injection away from the dominant injector, RK24. We also map the spatial distribution of the earthquake frequency-magnitude distribution, or b-value, and show that it increases from ∼1.0 to ∼1.5 with increasing depth below the reservoir. As has been proposed at other reservoirs, we infer that these spatial variations reflect the distribution of pressure in the reservoir, where areas of high b-value correspond to areas of high pore-fluid pressure and a broad distribution of activated fractures. This analysis is not routinely conducted by geothermal operators but shows promise for using earthquake b-value as an additional tool for reservoir monitoring and management

The stellar mass function of galaxies to z ~ 5 in the Fors Deep and GOODS-S fields

We present a measurement of the evolution of the stellar mass function (MF) of galaxies and the evolution of the total stellar mass density at 0<z<5. We use deep multicolor data in the Fors Deep Field (FDF; I-selected reaching I_AB=26.8) and the GOODS-S/CDFS region (K-selected reaching K_AB=25.4) to estimate stellar masses based on fits to composite stellar population models for 5557 and 3367 sources, respectively. The MF of objects from the GOODS-S sample is very similar to that of the FDF. Near-IR selected surveys hence detect the more massive objects of the same principal population as do I-selected surveys. We find that the most massive galaxies harbor the oldest stellar populations at all redshifts. At low z, our MF follows the local MF very well, extending the local MF down to 10^8 Msun. The faint end slope is consistent with the local value of alpha~1.1 at least up to z~1.5. Our MF also agrees very well with the MUNICS and K20 results at z<2. The MF seems to evolve in a regular way at least up to z~2 with the normalization decreasing by 50% to z=1 and by 70% to z=2. Objects having M>10^10 Msun which are the likely progenitors of todays L* galaxies are found in much smaller numbers above z=2. However, we note that massive galaxies with M>10^11 Msun are present even to the largest redshift we probe. Beyond z=2 the evolution of the mass function becomes more rapid. We find that the total stellar mass density at z=1 is 50% of the local value. At z=2, 25% of the local mass density is assembled, and at z=3 and z=5 we find that at least 15% and 5% of the mass in stars is in place, respectively. The number density of galaxies with M>10^11 Msun evolves very similarly to the evolution at lower masses. It decreases by 0.4 dex to z=1, by 0.6 dex to z=2, and by 1 dex to z=4.Comment: Accepted for publication in ApJ

Phenology satellite experiment

The detection of a phenological event (the brown wave-vegetation senescence) for specific forest and crop types using ERTS-1 imagery is described. Data handling techniques included computer analysis and photo interpretation procedures. Computer analysis of ERTS-1 multispectral scanner digital tapes in all bands was used to give the relative changes of spectral reflectance with time of forests and specified crops. These data were obtained for a number of the study's twenty-four sites located within four north-south corridors across the United States. Analysis of ground observation photography and ERTS-1 imagery for sites in the Appalachian Corridor and Mississippi Valley Corridor indicates that the recession of vegetation development can be detected very well. Tentative conclusions are that specific phenological events such as crop maturity or leaf fall can be mapped for specific sites and possibly for entire regions

Baade's red sheet resolved into stars with HST in the Blue Compact Dwarf Galaxy VII Zw 403

HST WFPC2 observations of the nearby Blue Compact Dwarf Galaxy VII~Zw~403 (= UGC 6456) resolve single stars down to M$_I$$\approx$-2.5, deep enough to identify red giants. This population has a more uniform spatial distribution than the young main-sequence stars and supergiants, forming the structure known as "Baade's red sheet". We conclude that VII~Zw~403 is not a primeval galaxy.Comment: submitted to: ApJ Letter

The malaria parasite cyclic GMP-dependent protein kinase plays a central role in blood-stage schizogony

A role for the Plasmodium falciparum cyclic GMP (cGMP)-dependent protein kinase (PfPKG) in gametogenesis in the malaria parasite was elucidated previously. In the present study we examined the role of PfPKG in the asexual blood-stage of the parasite life cycle, the stage that causes malaria pathology. A specific PKG inhibitor (compound 1, a trisubstituted pyrrole) prevented the progression of P. falciparum schizonts through to ring stages in erythrocyte invasion assays. Addition of compound 1 to ring-stage parasites allowed normal development up to 30 h postinvasion, and segmented schizonts were able to form. However, synchronized schizonts treated with compound 1 for ≥6 h became large and dysmorphic and were unable to rupture or liberate merozoites. To conclusively demonstrate that the effect of compound 1 on schizogony was due to its selective action on PfPKG, we utilized genetically manipulated P. falciparum parasites expressing a compound 1-insensitive PfPKG. The mutant parasites were able to complete schizogony in the presence of compound 1 but not in the presence of the broad-spectrum protein kinase inhibitor staurosporine. This shows that PfPKG is the primary target of compound 1 during schizogony and provides direct evidence of a role for PfPKG in this process. Discovery of essential roles for the P. falciparum PKG in both asexual and sexual development demonstrates that cGMP signaling is a key regulator of both of these crucial life cycle phases and defines this molecule as an exciting potential drug target for both therapeutic and transmission blocking action against malaria

Representations of racial minorities in popular movies: A content-analytic synergy of computer vision and network science

In the Hollywood film industry, racial minorities remain underrepresented. Characters from racially underrepresented groups receive less screen time, fewer central story positions, and frequently inherit plotlines, motivations, and actions that are primarily driven by White characters. Currently, there are no clearly defined, standardized, and scalable metrics for taking stock of racial minorities’ cinematographic representation. In this paper, we combine methodological tools from computer vision and network science to develop a content analytic framework for identifying visual and structural racial biases in film productions. We apply our approach on a set of 89 popular, full-length movies, demonstrating that this method provides a scalable examination of racial inclusion in film production and predicts movie performance. We integrate our method into larger theoretical discussions on audiences’ perception of racial minorities and illuminate future research trajectories towards the computational assessment of racial biases in audiovisual narratives

The old and heavy bulge of M31 I. Kinematics and stellar populations

We present new optical long-slit data along 6 position angles of the bulge region of M31. We derive accurate stellar and gas kinematics reaching 5 arcmin from the center, where the disk light contribution is always less than 30%, and out to 8 arcmin along the major axis, where the disk makes 55% of the total light. We show that the velocity dispersions of McElroy (1983) are severely underestimated (by up to 50 km/s) and previous dynamical models have underestimated the stellar mass of M31's bulge by a factor 2. Moreover, the light-weighted velocity dispersion of the galaxy grows to 166 km/s, thus reducing the discrepancy between the predicted and measured mass of the black hole at the center of M31. The kinematic position angle varies with distance, pointing to triaxiality. We detect gas counterrotation near the bulge minor axis. We measure eight emission-corrected Lick indices. They are approximately constant on circles. We derive the age, metallicity and alpha-element overabundance profiles. Except for the region in the inner arcsecs of the galaxy, the bulge of M31 is uniformly old (>12 Gyr, with many best-fit ages at the model grid limit of 15 Gyr), slightly alpha-elements overabundant ([alpha/Fe]~0.2) and at solar metallicity, in agreement with studies of the resolved stellar components. The predicted u-g, g-r and r-i Sloan color profiles match reasonably well the dust-corrected observations. The stellar populations have approximately radially constant mass-to-light ratios (M/L_R ~ 4-4.5 for a Kroupa IMF), in agreement with stellar dynamical estimates based on our new velocity dispersions. In the inner arcsecs the luminosity-weighted age drops to 4-8 Gyr, while the metallicity increases to above 3 times the solar value.Comment: Accepted for publication in A&

The Kormendy relation of massive elliptical galaxies at z~1.5. Evidence for size evolution ?

We present the morphological analysis based on HST-NIC2 (0.075 arcsec/pixel) images in the F160W filter of a sample of 9 massive field (> 10^{11} M_\odot) galaxies spectroscopically classified as early-types at 1.2<z<1.7. Our analysis shows that all of them are bulge dominated systems. In particular, 6 of them are well fitted by a de Vaucouleurs profile (n=4) suggesting that they can be considered pure elliptical galaxies. The remaining 3 galaxies are better fitted by a Sersic profile with index 1.9<n<2.3 suggesting that a disk-like component could contribute up to 30% to the total light of these galaxies. We derived the effective radius R_e and the mean surface brightness within R_e of our galaxies and we compared them with those of early-types at lower redshifts. We find that the surface brightness of our galaxies should get fainter by 2.5 mag from z~1.5 to z~0 to match the surface brightness of the local ellipticals with comparable R_e, i.e. the local Kormendy relation. Luminosity evolution without morphological changes can only explain half of this effect, as the maximum dimming expected for an elliptical galaxy is ~1.6 mag in this redshift range. Thus, other parameters, possibly structural, may undergo evolution and play an important role in reconciling models and observations. Hypothesizing an evolution of the effective radius of galaxies we find that R_e should increase by a factor 1.5 from z~1.5 to z~0.Comment: Accepted for publication in MNRAS, 15 pages, 8 figure