Near-infrared reddening of extra-galactic GMCs in a face-on geometry

[Abridged] We describe the near-infrared reddening signature of giant molecular clouds (GMCs) in external galaxies. In particular, we examine the E(J-H) and E(H-K) color-excesses, and the effective extinction law observed in discrete GMC regions. We also study the effect of the relative scale height of the GMC distribution to the color-excesses, and to the observed mass function of GMCs. We perform Monte Carlo radiative transfer simulations with 3D models of stellar radiation and clumpy dust distributions, resembling a face-on geometry. The scattered light is included in the models, and near-infrared color maps are calculated from the simulated data. The effective near-infrared reddening law, i.e. the ratio E(J-H)/E(H-K), has a value close to unity in GMC regions. The ratio depends on the relative scale height of GMCs, xi, and for xi values 0.1...0.75 we find the typical ratios of 0.6...1.1. The effective extinction law turns out to be very flat in GMC regions. We find the ratios of apparent extinctions of A(H)/A(K)=1.35...1.55 and A(J)/A(H)=1.15. The effect of the scattered flux on the effective reddening law, as well as on the effective extinction law, is significant. Regarding the GMC mass function, we find no correlation between the input and observed slopes of the mass functions. Rather, the observed slope reflects the parameter $\xi$ and the dynamical range of the mass function. We estimate that only a fraction of 10...20 % of the total mass of GMCs is recovered, if the observed color-excess values are transformed to masses using the Galactic reddening law. In the case of individual clouds the fraction can vary between ~0...50 %.Comment: 8 pages, 10 figures, accepted for publication in A&A. Added missing histograms in Fig.

Magnification relations in gravitational lensing via multidimensional residue integrals

We investigate the so-called magnification relations of gravitational lensing models. We show that multidimensional residue integrals provide a simple explanation for the existence of these relations, and an effective method of computation. We illustrate the method with several examples, thereby deriving new magnification relations for galaxy lens models and microlensing (point mass lensing).Comment: 16 pages, uses revtex4, submitted to Journal of Mathematical Physic

ANAEROBIC POWER AND DEVELOPMENT OF FATIGUE IN FREESTYLE SPRINT SWIMMING

INTRODUCTION -In literature there are conflicting views on the relationship between anaerobic swimming and dry-land power (CostiI1/1983; Höltke! 1992; Johnson!1993; Tanaka/1993). In 100 m -freestyle swimming the highest speed are reached at the beginning. The values vary between 95 and 100 % of individual maximum in the first and between 85 and 90 % in the last quarter. Differences in the final time are results of lower speed at beginning and! or of higher decrease in swim velocity during the race (Küehler!1993). This decrease of velocity is an expression of muscle fatigue. The results of competition analyses of top athletes correspond to results of dry-land power tests on' the biokinetic swim bench. METHODS -Members of the German national swim team were tested on the biokinetic swim bench. 22 athletes performed a test lasting one minute on level 5. The work per repetition was represented in percent of the personal maximum. Additionally for some athletes the 5 m -and 100 m freestyle sprint speed were analysed. The swimming speed in 100 m -sprint was expressed in percent from the maximum in 50 m -sprint. RESULTS -Summary shows table 1. Athletes a, c and E show similar intensities in swim race and dry-land test. Athlete 9 performed only low intensities at the beginning in both tests. This is not typical for sprinters. Decrease in intensity in dry-land power test characterises the level of anaerobic glycol tie metabolism. In this respect individual differences between top athletes were found. We observed variations in intensity at tests on the biokinetic swim bench during the year too. This is an expression of variations of metabolic muscle properties. Dryland testing on a swim bench can help the athlete to know more about metabolic properties of his "swim" muscles in the whole season. For a comparison of swimming and dry-land power it is necessary to use relative values in form of intensity of the maximum. REFERENCES -Costill, D. L, Douglas, S. K., Holdren, A. & Hargreaves, M. (1983). Sprint speed vs. swimming power. Swimming Technique, Val 20, 20-22. Höltke. V. (1992). Zur Effektivität von dynamischem Maximalkraft• und dynamischem Kraftausdauertraining bei Leistungsschwimmem der nationalen Spitzenklasse: ein Trainings experiment im Hochleistungssport. Erlen ee: SFT-Ver1ag. Johnson, R. E., Sharp, R. L. & Hedrick, C. E. (1993). Relatlonship of swimming power and dryland power to sprint freestyle performance: a multiple regression approach. J. Swimming Research, Val 0, 10-14 KOchler, J., L opold, H. & Leopold, W. (1993) Vergleichende Betrachtungen der Gestallun der Wettkämpfe der 50 m-und 100 mSchwimmdisziplinen der Besten der Olympischen Spiele 1992 und deutscher Spitzenschwimmer. IAT Leipzig. 28 S. Tanaka, H., Costill, D. L., Thomas, R., Fink, W. J. & Widrick, J J. (1993). Dry-land re• sistance training for competitive swimming. Med. Sei. Exer ., Vol. 25. No. 8, 952-959

MOTOR LEARNING AND MUSCULAR REQUESTS FOR RAPID AIR-BORN ROTATIONS

INTRODUCION - Air-borne human rotational movements represent a complicated problem of theoretical mechanics. Many studies have been presented during the recent years by YEADON (1984) and HILDEBRAND (1985) and other authors to gain new knowledge on mechanic principles. In these studies the athlete was considered to be a multi-link system of rigid bodies. Besides these studies there is a variety of publications on general physiological phenomena during human rotational movements. It is interesting to know that there is until now no publication on motor learning and muscular requests for rapid air- borne rotations of athletes. METHODS - The research design is made up of state-of-the-art analyses in figure skating, trampolining, diving and gymnastics to determine recent performance limits, biomechanical studies including 3D-analyses and electromyographic procedures as well. as training-scientific studies (specific measuring devices for biomechanical and EEG studies). RESULTS AND DISCUSSION - In analyses of different rotational movements of international top athletes in the sports mentioned above we found h~gh angular velocities in different disciplines (table 1). These velocity values prove extremely high requests for the information processing systems of movement co-ordination. During different methodical exercises and jumps in figure skating, diving and gymnastics electro-myographical studies of 12 relevant muscles of the trunk and neck using 3D analyses were linked and coordination patterns were compared. Activation waves of trunk muscles prove cycles of the recruited muscles with a frequency ranging from 3 to 4 Hz (depending on angular velocity in rotational movements on the longitudinal axis). Here obviously movement automation occurs since interviews with athletes on what they are focusing on in orientation during movement regulation only produced a few and simple "control impulses". Using EEG procedures we could verify that active movement imagery or movement performance imagery is an important part of learning complicated air-borne rotations. Table 1: Angular velocities (degls) in different disciplines REFERENCES - HILDEBRAND, F. (1 985). Eine biomechanische Analyse der Drehbewegungen des menschlichen Korpers. Leipzig. Habilitation. YEADON, M. R. (1984). The mechanics of twisting somersaults. Loughborough. Doctoral Thesis. YEADON, M. R. (1994). Twisting techniques used in dismounts from the rings. International Journal of Sport Biomechanics. Champaign

Expansion of the Planet Detection Channels in Next-Generation Microlensing Surveys

We classify various types of planetary lensing signals and the channels of detecting them. We estimate the relative frequencies of planet detections through the individual channels with special emphasis on the new channels to be additionally provided by future lensing experiments that will survey wide fields continuously at high cadence by using very large-format imaging cameras. From this investigation, we find that the fraction of wide-separation planets that would be discovered through the new channels of detecting planetary signals as independent and repeating events would be substantial. We estimate that the fraction of planets detectable through the new channels would comprise ~15 -- 30% of all planets depending on the models of the planetary separation distribution and mass ratios of planets. Considering that a significant fraction of planets might exist in the form of free-floating planets, the frequency of planets to be detected through the new channel would be even higher. With the expansion of the channels of detecting planet, future lensing surveys will greatly expand the range of planets to be probed.Comment: 6 pages, 3 figures, one tabl

On the missing 2175 Angstroem-bump in the Calzetti extinction curve

The aim of the paper is to give a physical explanation of the absence of the feature in the Calzetti extinction curve. We analyze the dust attenuation of a homogeneous source seen through a distant inhomogeneous distant screen. The inhomogeneities are described through an idealized isothermal turbulent medium where the probability distribution function (PDF) of the column density is log-normal. In addition it is assumed that below a certain critical column density the carriers of the extinction bump at 2175 Angstroem are being destroyed by the ambient UV radiation field. Turbulence is found to be a natural explanation not only of the flatter curvature of the Calzetti extinction curve but also of the missing bump provided the critical column density is N_H >= 10^21 cm^-2. The density contrast needed to explain both characteristics is well consistent with the Mach number of the cold neutral medium of our own Galaxy which suggests a density contrast sigma_(rho/) 6.Comment: 6 pages, 6 figures accepted for publication in A&A, section

Star-dust geometries in galaxies: The effect of interstellar matter distributions on optical and infrared properties of late-type galaxies

The presence of substantial amounts of interstellar dust in late-type galaxies affects observable parameters such as the optical surface brightness, the color, and the ratio of far-infrared to optical luminosity of these galaxies. We conducted radiative transfer calculations for late-type galaxy environments to examine two different scenarios: (1) the effects of increasing amounts of dust in two fixed geometries with different star distributions; and (2) the effects of an evolving dust-star geometry in which the total amount of dust is held constant, for three different star distributions. The calculations were done for ten photometric bands, ranging from the far-ultraviolet to the near-infrared (K), and scattered light was included in the galactic surface brightness at each wavelength. The energy absorbed throughout these ten photometric bands was assumed to re-emerge in the far-infrared as thermal dust emission. We also considered the evolutionary contraction of a constant amount of dust relative to pre-existing star distributions

A Characteristic Planetary Feature in Double-Peaked, High-Magnification Microlensing Events

A significant fraction of microlensing planets have been discovered in high-magnification events, and a significant fraction of these events exhibit a double-peak structure at their peak. However, very wide or very close binaries can also produce double-peaked high-magnification events, with the same gross properties as those produced by planets. Traditionally, distinguishing between these two interpretations has relied upon detailed modeling, which is both time-consuming and generally does not provide insight into the observable properties that allow discrimination between these two classes of models. We study the morphologies of these two classes of double-peaked high-magnification events, and identify a simple diagnostic that can be used to immediately distinguish between perturbations caused by planetary and binary companions, without detailed modeling. This diagnostic is based on the difference in the shape of the intra-peak region of the light curves. The shape is smooth and concave for binary lensing, while it tends to be either boxy or convex for planetary lensing. In planetary lensing this intra-peak morphology is due to the small, weak cusp of the planetary central caustic located between the two stronger cusps. We apply this diagnostic to five observed double-peaked high-magnification events to infer their underlying nature. A corollary of our study is that good coverage of the intra-peak region of double-peaked high-magnification events is likely to be important for their unique interpretation.Comment: 6 pages, 3 figure

Double precision trajectory program /DPTRAJ 2.2C/

Four part program computes trajectory of space probe moving in solar system and subject to variety of forces

Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010

In December 2010 the last campaign of the German-Norwegian sounding rocket project ECOMA (Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was conducted from Andøya Rocket Range in northern Norway (69° N, 16° E) in connection with the Geminid meteor shower. The main instrument on board the rocket payloads was the ECOMA detector for studying meteoric smoke particles (MSPs) by active photoionization and subsequent detection of the produced charges (particles and photoelectrons). In addition to photoionizing MSPs, the energy of the emitted photons from the ECOMA flash-lamp is high enough to also photoionize nitric oxide (NO). Thus, around the peak of the NO layer, at and above the main MSP layer, photoelectrons produced by the photoionization of NO are expected to contribute to, or even dominate above the main MSP-layer, the total measured photoelectron current. Among the other instruments on board was a set of two photometers to study the O2 (b1Σg+−X3Σg) Atmospheric band and NO2 continuum nightglow emissions. In the absence of auroral emissions, these two nightglow features can be used together to infer NO number densities. This will provide a way to quantify the contribution of NO photoelectrons to the photoelectron current measured by the ECOMA instrument and, above the MSP layer, a simultaneous measurement of NO with two different and independent techniques. This work is still on-going due to the uncertainties, especially in the effort to quantitatively infer NO densities from the ECOMA photoelectron current, and the lack of simultaneous measurements of temperature and density for the photometric study. In this paper we describe these two techniques to infer NO densities and discuss the uncertainties. The peak NO number density inferred from the two photometers on ascent was 3.9 × 108 cm−3 at an altitude of about 99 km, while the concentration inferred from the ECOMA photoelectron measurement at this altitude was a factor of 5 smaller