Space telescope searches for black holes in galactic nuclei

The Hubble Space Telescope (HST) will allow astronomers to obtain luminosity profiles, rotation curves, and velocity dispersions at angular scales that are an order of magnitude superior to those obtained previously. This enhanced spatial resolution will greatly improve the sensitivity for detecting centrally condensed matter in nearby galactic nuclei including, possibly, black holes

Microfield Dynamics of Black Holes

The microcanonical treatment of black holes as opposed to the canonical formulation is reviewed and some major differences are displayed. In particular the decay rates are compared in the two different pictures.Comment: 22 pages, 4 figures, Revtex, Minor change in forma

Quantum-Noise Power Spectrum of Fields with Discrete Classical Components

We present an algorithmic approach to calculate the quantum-noise spectral density of photocurrents generated by optical fields with arbitrary discrete classical spectrum in coherent or squeezed states. The measurement scheme may include an arbitrary number of demodulations of the photocurrent. Thereby, our method is applicable to the general heterodyne detection scheme which is implemented in many experiments. For some of these experiments, e.g. in laser-interferometric gravitational-wave detectors, a reliable prediction of the quantum noise of fields in coherent and squeezed states plays a decisive role in the design phase and detector characterization. Still, our investigation is limited in two ways. First, we only consider coherent and squeezed states of the field and second, we demand that the photocurrent depends linearly on the field's vacuum amplitudes which means that at least one of the classical components is comparatively strong.Comment: 8 pages, 2 figure

Seismic topographic scattering in the context of GW detector site selection

In this paper, we present a calculation of seismic scattering from irregular surface topography in the Born approximation. Based on US-wide topographic data, we investigate topographic scattering at specific sites to demonstrate its impact on Newtonian-noise estimation and subtraction for future gravitational-wave detectors. We find that topographic scattering at a comparatively flat site in Oregon would not pose any problems, whereas scattering at a second site in Montana leads to significant broadening of wave amplitudes in wavenumber space that would make Newtonian-noise subtraction very challenging. Therefore, it is shown that topographic scattering should be included as criterion in the site-selection process of future low-frequency gravitational-wave detectors.Comment: 16 pages, 7 figure

PP-waves on Superbrane Backgrounds

In this paper we discuss a method of generating supersymmetric solutions of the Einstein equations. The method involves the embedding of one supersymmetric spacetime into another. We present two examples with constituent spacetimes which support "charges", one of which was known previously and the other of which is new. Both examples have PP-waves as one of the embedding constituents.Comment: 6 pages no figure

Density, Abundance, and Habitat Associations of the Inland Swamp Sparrow (Melospiza georgiana georgiana) in Iowa

Wetlands continue to decline throughout North America and the Prairie Pothole Region, thus emphasizing the importance of understanding population trends and habitat associations of wetland species to ensure effective conservation and habitat management of those species. We estimated density and abundance and evaluated habitat associations of the Inland Swamp Sparrow (Melospiza georgiana georgiana) in Iowa. We conducted standardized distance sampling surveys for Swamp Sparrows and measured habitat characteristics at 307 wetlands in two regions of Iowa in 2009 and 2010. We used Program Distance to model detection probability and estimate region-specific breeding densities of Swamp Sparrows at Iowa wetlands. We then extrapolated density estimates to the total area of wetlands in each region to obtain estimates of breeding abundance. We correlated Swamp Sparrow counts to nine habitat variables using Poisson regression in Program R. Swamp Sparrow counts were positively correlated with percent cover of cattail (Typha spp.) and water depth (cm) and negatively correlated with percent cover of woody vegetation, vegetation size (m), and wetland size (ha). We estimated breeding densities of Swamp Sparrows to be 1.488 birds/ha (95% CI = 1.308 − 1.692) in region 1 (Des Moines Lobe landform) and 0.041 birds/ha (95% CI = 0.006 − 0.275) in region 2 (remainder of the state). Our results, in comparison to those of other studies, indicate that Swamp Sparrows associate with a variety of wetland characteristics depending upon what is available. Swamp Sparrows are relatively uncommon breeders in Iowa, and our work confirms that most occur in the Des Moines Lobe landform in north-central and northwestern Iowa. Biologists and land managers should incorporate our findings on this species’ habitat associations into management activities to ensure that Swamp Sparrow populations persist into the future

First Record of a Comb Duck (Sarkidiornis melanotos sulvicola) for Costa Rica

The authors, in company with Rafael Ramirez and a group of Iowa State University students, observed, photographed, and documented a male Comb Duck of the South American subspecies (Sarkidiornis melanotos sylvicola) at the large drying wetland in Palo Verde National Park, Costa Rica on 18 March 2010. The bird was present the following day and last reported 25 March 2010. The record is supported by photographs and becomes the first for Costa Rica and northernmost in the Western Hemisphere

Influence of Season and Time of Day on Marsh Bird Detections

Call-broadcast surveys are frequently used to elicit responses of secretive marsh birds and produce greater detection rates than passive surveys. However, little is known about how detection rates of birds from these surveys differ by season and time of day. We conducted call-broadcast surveys for eight focal species at 56 wetlands throughout Iowa from 15 May–13 June 2010 (early season) and from 15 June–10 July 2010 (late season). Our focal species were Pied-billed Grebe (Podilymbus podiceps), American Bittern (Botaurus lentiginosus), Least Bittern (Ixobrychus exilis), King Rail (Rallus elegans), Virginia Rail (Rallus limicola), Sora (Porzana carolina), Common Gallinule (Gallinula chloropus), and American Coot (Fulica americana). Surveys were conducted in the early morning (30 mins before sunrise to 3 hrs after sunrise) and late evening (3 hrs before sunset to 30 mins after sunset) in accordance with the North American Marsh Bird Monitoring Protocol. We evaluated marsh bird detection rates as a function of a) time of day (morning and evening survey periods), b) season (early and late in the breeding season), and c) wetland size for four species with the greatest detection rates (Pied-billed Grebe, Least Bittern, Virginia Rail, and Sora). We also evaluated the above effects for two species groups; all eight species pooled and all rails pooled. We found significant (P \u3c 0.05) effects on the number of detections for Pied-billed Grebe in response to time of day, time of season, and wetland size; Sora, Virginia Rail, all rails, and all species had an effect of time of season only. Understanding seasonal and time-of-day differences in detection rates, as well as area dependence of secretive marsh birds, will refine existing monitoring protocols by allowing researchers to maximize detection probabilities of target species