Search

We study an assembly-type bias parametrized by the dimensionless spin parameter that affects massive structures. In numerical simulations, higher spin haloes are more strongly clustered than lower spin haloes of equal mass. We detect a difference of over 30 per cent in the clustering strength for dark matter haloes of 1013–1014 h−1 M⊙, which is similar to the result of Bett et al. We explore whether the dependence of clustering strength on halo spin is removed if we apply the redefinition of overdensity peak height proposed by Lacerna & Padilla (Paper I) obtained using assembly ages. We find that this is not the case due to two reasons. First, only a few objects of low virial mass are moved into the mass range where the spin introduces an assembly-type bias after using this redefinition. Secondly, this formalism does not alter the mass of massive objects. In other words, the sample of haloes with redefined mass M in the high-mass regime is practically the same as before the redefinition of peak height, and thus the clustering behaviour is the same. We then repeat the process of finding the redefined peak height of Paper I but using the spin. In this case, the new masses show no spin-related assembly bias but they introduce a previously absent assembly bias with respect to relative age. From this result, we conclude that the assembly-type bias with respect to the halo spin has a different origin from that with respect to the assembly age. The former may be due to the material from filaments, which is accreted by massive haloes, and enhanced in high-density environments, thus causing more extreme spin values without significantly changing the formation age of the halo. In addition, the estimates of the mass of collapsed structures in numerical simulations could be lower than the true mass, even in cluster-size haloes. High-mass objects may correspond, in some cases, to a different peak height from that suggested by their virial mass, providing a possible explanation for the assembly-type bias with respect to the spin.

Exoplanets which are detected using the radial velocity technique have a well-known ambiguity of their true mass, caused by the unknown inclination of the planetary orbit with respect to the plane of the sky. Constraints on the inclination are aided by astrometric follow-up in rare cases or, in ideal situations, through subsequent detection of a planetary transit. As the predicted inclination decreases, the mass of the companion increases leading to a change in the predicted properties. Here we investigate the changes in the mass, radius, and atmospheric properties as the inclination pushes the companion from the planetary into the brown dwarf and finally low-mass star regimes. We determine the resulting detectable photometric signatures in the predicted phase variation as the companion changes properties and becomes self-luminous. We apply this to the HD 114762 and HD 162020 systems for which the minimum masses of the known companions places them at the deuterium-burning limit.

The fully analytical solution for isothermal Bondi accretion on a black hole (MBH) at the center of two-component Jaffe (1983) galaxy models is presented. In a previous work we provided the analytical expressions for the critical accretion parameter and the radial profile of the Mach number in the case of accretion on a MBH at the center of a spherically symmetric one-component Jaffe galaxy model. Here we apply this solution to galaxy models where both the stellar and total mass density distributions are described by the Jaffe profile, with different scale-lengths and masses, and to which a central MBH is added. For such galaxy models all the relevant stellar dynamical properties can also be derived analytically (Ciotti & Ziaee Lorzad 2018). In these new models the hydrodynamical and stellar dynamical properties are linked by imposing that the gas temperature is proportional to the virial temperature of the galaxy stellar component. The formulae that are provided allow to evaluate all flow properties, and are then useful for estimates of the scale-radius and the mass flow rate when modeling accretion on massive black holes at the center of galaxies. As an application, we quantify the departure from the true mass accretion rate of estimates obtained using the gas properties at various distances from the MBH, under the hypothesis of classical Bondi accretion., 14 pages, 7 figures, submitted to ApJ, comments welcome

Using gravity description, we compute various static length scales of N=6 Chern Simons plasma in a strongly coupled regime. For this, we consider the CP3 compactification of the type IIA supergravity down to four dimensions, and identify all the low-lying bosonic modes up to masses corresponding to the operator dimension 3 together with all the remaining CP3 invariant modes. We find the true mass gap, the Debye screening mass and the corresponding dual operators to be probed in the field theory side., 12pages, Small additions

The twin Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) COR2 coronagraphs of the Solar Terrestrial Relations Observatory (STEREO) provide images of the solar corona from two view points in the solar system. Since their launch in late 2006, the STEREO Ahead (A) and Behind (B) spacecrafts have been slowly separating from Earth at a rate of 22.5 degrees per year. By the end of 2007, the two spacecraft were separated by more than 40 degrees from each other. At this time, we began to see large-scale differences in the morphology and total intensity between coronal mass ejections (CMEs) observed with SECCHI-COR2 on STEREO-A and B. Due to the effects of the Thomson scattering geometry, the intensity of an observed CME is dependent on the angle it makes with the observed plane of the sky. From the intensity images, we can calculate the integrated line of sight electron density and mass. We demonstrate that is is possible to simultaneously derive the direction and true total mass of the CME if we make the simple assumption that the same mass should be observed in COR2-A and B.

Asymmetric rotating disc contactor (ARDC) offers potential advantages in having comparable mass transfer coefficient ( k C a _ ) and lower back mixing over the conventional rotating disc contactor (RDC). In the present work, measurements of dispersed phase hold-up (∈D), effective interfacial area ( a _ ), continuous phase mass transfer coefficient ( k C a _ ) and axial dispersion coefficient for the dispersed as well as continuous phase have been performed in 80 mm and 150 mm i.d. ARDC over a wide range of operating variables and physical properties. From these measurements, the values of slip velocity and sauter mean drop diameter (d3,2) have been estimated. Suitable correlations have been proposed for ∈D, VS, k C a _ , a _ , kC, d3,2, PeC and PeD. The results on true mass transfer coefficient (kC) have been compared with those published in the literature.

The study of young stellar populations has revealed that most stars are in binary or higher order multiple systems. In this study the influence on the stellar initial mass function (IMF) of large quantities of unresolved multiple massive stars is investigated by taking into account stellar evolution and photometrically determined system masses. The models where initial masses are derived from the luminosity and colour of unresolved multiple systems show that even under extreme circumstances (100% binaries or higher order multiples) the difference between the power-law index of the mass function of all stars and the observed mass function is small (~0.1). Thus, if the observed IMF has the Salpeter index alpha = 2.35 then the true stellar IMF has an index not flatter than alpha = 2.25. Additionally, unresolved multiple systems may hide between 15 and 60% of the underlying true mass of a star cluster. While already a known result, it is important to point out that the presence of a large number of unresolved binaries amongst pre-main-sequence (PMS) stars induces a significant spread in the measured ages of these stars even if there is none. Also, lower-mass stars in a single-age binary-rich cluster appear older than the massive stars by about 0.6 Myr., Comment: accepted for publication in MNRAS, 27 pages, 12 figures, 4 tables

A novel mass flow detector has been developed using an open cylindrical resonator based on two microstrip patch couplers. The directivity of the couplers provides a compact sensor design without loss of sensitivity. The design of a particulate mass flow detector and the algorithm to detect the average solids concentration is shown. Spatial filtering velocimetry is applied to a microstrip patch sensor in order to detect the average particulate velocity. The simultaneous detection of the velocity and the solids/air concentration from a single measurement, ensure a true mass flow detector. Subsequently, free fall measurements as well as measurements in a self contained material flow measuring system were carried out in order to prove the concept.

The quantity Y_ X, the product of the X-ray temperature T_ X and gas mass M_ g, has recently been proposed as a robust low-scatter mass indicator for galaxy clusters. Using precise measurements from XMM-Newton data of a sample of 10 relaxed nearby clusters, spanning a Y_ X range of 10^13 -10^15 M_sun keV, we investigate the M_500-Y_ X relation. The M_500 - Y_ X data exhibit a power law relation with slope alpha=0.548 \pm 0.027, close to the self-similar value (3/5) and independent of the mass range considered. However, the normalisation is \sim 20% below the prediction from numerical simulations including cooling and galaxy feedback. We discuss two effects that could contribute to the normalisation offset: an underestimate of the true mass due to the HE assumption used in X-ray mass estimates, and an underestimate of the hot gas mass fraction in the simulations. A comparison of the functional form and scatter of the relations between various observables and the mass suggest that Y_ X may indeed be a better mass proxy than T_ X or M_g,500., Comment: 4 pages, 2 figures, accepted for publication in A&A

We have determined a dynamical mass for the companion to HD 33636 which indicates it is a low-mass star instead of an exoplanet. Our result is based on an analysis of Hubble Space Telescope (HST) astrometry and ground-based radial velocity data. We have obtained high-cadence radial velocity measurements spanning 1.3 years of HD 33636 with the Hobby-Eberly Telescope at McDonald Observatory. We combined these data with previously published velocities to create a data set that spans nine years. We used this data set to search for, and place mass limits on, the existence of additional companions in the HD 33636 system. Our high-precision astrometric observations of the system with the HST Fine Guidance Sensor 1r span 1.2 years. We simultaneously modeled the radial velocity and astrometry data to determine the parallax, proper motion, and perturbation orbit parameters of HD 33636. Our derived parallax, pi = 35.6 +/- 0.2 mas, agrees within the uncertainties with the Hipparcos value. We find a perturbation period P = 2117.3 +/- 0.8 days, semimajor axis a_A = 14.2 +/- 0.2 mas, and system inclination i = 4.1 +/- 0.1 deg. Assuming the mass of the primary star M_A = 1.02 +/- 0.03 M_sun, we obtain a companion mass M_B = 142 +/- 11 M_jup = 0.14 +/- 0.01 M_sun. The much larger true mass of the companion relative to its minimum mass estimated from the spectroscopic orbit parameters (M sin i = 9.3 M_jup) is due to the near face-on orbit orientation. This result demonstrates the value of follow-up astrometric observations to determine the true masses of exoplanet candidates detected with the radial velocity method., 33 pages, 6 figures, accepted for publication in AJ; added reference to section 6

Context. CO observations have been the best way so far to trace molecular gas in external galaxies, but in low metallicity environments the gas mass deduced could be largely underestimated due to enhanced photodissociation of the CO molecule. Large envelopes of H2 could therefore be missed by CO observations. Aims. At present, the kinematic information of CO data cubes are used to estimate virial masses and trace the total mass of the molecular clouds. Millimeter dust emission can also be used as a dense gas tracer and could unveil H2 envelopes lacking CO. These different tracers must be compared in different environments. Methods. This study compares virial masses to masses deduced from millimeter emission, in two GMC samples: the local molecular clouds in our Galaxy (10 4 −10 5 M� ), and their equivalents in the Small Magellanic Cloud (SMC), one of the nearest low metallicity dwarf galaxies. Results. In our Galaxy, mass estimates deduced from millimeter (FIRAS) emission are consistent with masses deduced from gamma ray analysis and therefore trace the total mass of the clouds. Virial masses are systematically larger (twice on average) than mass estimates from millimeter dust emission. This difference decreases toward high masses and has been reported in previous studies. This is not the case for SMC giant molecular clouds: molecular cloud masses deduced from SIMBA millimeter observations are systematically higher (twice on average for conservative values of the dust to gas ratio and dust emissivity) than the virial masses from SEST CO observations. The observed excess cannot be accounted for by any plausible change of dust properties. Taking a general form for the virial theorem, we show that a magnetic field strength of ∼15 µG in SMC clouds could provide additional support for the clouds and explain the difference observed. Conclusions. We conclude that masses of SMC molecular clouds have so far been underestimated. Magnetic pressure may contribute significantly to their support.

[Abridged] The giant molecular clouds (GMCs) of external galaxies can be mapped with sub-arcsecond resolution using multiband observations in the near-infrared. However, the interpretation of the observed features, and their transformation into physical quantities, is greatly hampered by the effects arising from the unknown geometry and the scattering of light by dust particles. We examine the relation between the observed NIR reddening and the column density of the dust clouds. In this paper we particularly assess the feasibility of deriving the mass function of GMCs from NIR color-excess data. We perform Monte Carlo radiative transfer simulations with 3D models of stellar radiation and clumpy dust distributions. We include the scattered light in the models and calculate NIR color maps from the simulated data. We extract clumps from the color maps and compare the observed mass function to the true mass function. For the physical configuration chosen in this study, essentially a face-on geometry, the observed mass function is a non-trivial function of the true mass function. The dynamical range of the observed mass function is confined to ~10^3.5... 10^5.5 M_\odot regardless of the dynamical range of the true mass function. The color maps are more sensitive in detecting the high-mass end of the mass function, and on average the masses of clouds are underestimated by a factor of ~10. The simulations show that the cloud mass function derived from JHK color excess data using simple foreground screening geometry cannot be regarded as a one-to-one tracer of the underlying mass function., 5 pages, 3 figures, accepted for publication in A&A

In this paper, a novel method for compensating mass air flow (MAF) sensor error due to installation and aging is developed by using adaptive observer. Through introducing a concept of membership function, the relative error on the grid points is represented as piecewise linear interpolation model which is expressed as dot product between regression vector and parameter vector. With the combination of relative error model and air intake model of diesel engine, the MAF sensor relative error estimation is described as linear parameter varying (LPV) system with unknown parameter vector, and the corresponding LPV adaptive observer is designed to estimate states and parameter jointly. The exponential convergence of the algorithm is proved under the conditions of some persistent excitation and given inequalities. In order to correct MAF sensor error online, the estimated relative error is further described as a map. The observer performance is validated against the simulation data from engine software enDYNA. The results demonstrate that the proposed method can estimate relative error, and the true mass air flow can be estimated by MAF sensor measurements with the error map.

We investigate the possibility of constraining the sin i degeneracy of alpha Cen B b -- with orbital period P=3.24 d; a = 0.042 AU; msini = 1.1 M_earth -- to estimate the true mass of the newly reported terrestrial exoplanet in the nearest stellar system to our Sun. We present detailed numerical simulations of the dynamical stability of the exoplanet in the alpha Cen AB binary system for a range of initial inclinations, eccentricities, and semi-major axes. The system represents a benchmark case for the interplay of the Kozai mechanism, general relativistic and tidal forces. From our simulations, there is only a small boundary in initial inclinations and initial semi-major axes that result in the migration via the Kozai mechanism of alpha Cen B b to its present location. Inside this boundary, the planet orbit is stable for up to 1 Gyr against the Kozai mechanism, and outside this boundary the planet collides with alpha Cen B or is ejected. In our three simulations where the planet migrates in towards the star via the Kozai mechanism, the final inclination is 46-53 degrees relative to the AB orbital plane, lower than the initial inclination of 75 degrees in each case. We discuss inclination constraints from the formation of alpha Cen B b in situ at its present location, migration in a proto-planetary disk, or migration in resonance with additional planets. We conclude that alpha Cen B b probably has a mass of less than 2.7 M_earth, implying a likely terrestrial composition warranting future confirmation., Comment: ApJ, accepted

The accuracy of mass measurements when using electronic balances is considered within the frame of analytical assays in terms of the uncertainty budget according to the internal quality control routine, the calibration process, the balance specifications, and the weighing scenarios. Buoyancy corrections for both conventional and true mass are fully discussed. The procedure is illustrated with a worked example.

We examine the systematics affecting the X-ray mass estimators applied to a set of five simulated galaxy clusters. They have been processed through the X-ray Map Simulator, X-MAS, to provide Chandra-like long exposures that are analyzed to reconstruct the gas temperature, density, and mass profiles used as input. We find that at R_2500 the mass profile obtained via a direct application of the hydrostatic equilibrium equation is consistent within 1 sigma with the actual mass; although we notice this estimator shows high statistical errors due to high level of Chandra background. Instead, the poorness of the beta-model in describing the gas density profile makes the evaluated masses to be underestimated by \sim 40 per cent with respect to the true mass, both with an isothermal and a polytropic temperature profile. We also test ways to recover the mass by adopting an analytic mass model, such as those proposed by Navarro et al. (1997) and Rasia et al. (2004), and fitting the temperature profile expected from the hydrostatic equilibrium equation to the observed one. These methods and the one of the hydrostatic equilibrium equation provide a more robust mass estimation than the ones based on the beta-model. In the present work the main limitation for a precise mass reconstruction is to ascribe to the relatively high level of the background chosen to reproduce the Chandra one. After artificially reducing it by a factor of 100, we find that the estimated mass significantly underestimates the true mass profiles. This is manly due (i) to the neglected contribution of the gas bulk motions to the total energy budget and (ii) to the bias towards lower values of the X-ray temperature measurements because of the complex thermal structure of the emitting plasma.

We present here the detection of a brown dwarf orbiting the A9V star HD180777. The radial velocity measurements, obtained with the ELODIE echelle spectrograph at the Haute-Provence Observatory, show a main variation with a period of 28.4 days. Assuming a primary mass of 1.7 Mo, the best Keplerian fit to the data leads to a minimum mass of 25 MJup for the companion (the true mass could be significantly higher). We also show that, after substraction of the Keplerian solution from the radial velocity measurements, the residual radial velocities are related to phenomena intrinsic to the star, namely pulsations with typical periods of Gamma Dor stars. These results show that in some cases, it is possible to disentangle radial velocity variations due to a low mass companion from variations intrinsic to the observed star., 7 pages, final version, accepted for publication (A&A)

We present the mass distribution in the central area of the cluster A 1689 by fitting over 100 multiply lensed images with the non-parametric Strong Lensing Analysis Package. The surface mass distribution is obtained in a robust way, finding a total mass of 0.25 x 10 15 h -1 M ○. within a 70-arcsec circle radius from the central peak. Our reconstructed density profile fits well a Navarro-Frenk-White (NFW) profile with small perturbations due to substructure, and is compatible with the more model-dependent analysis of Broadhurst et al. based on the same data. Our estimated mass does not rely on any prior information about the distribution of dark matter in the cluster. The peak of the mass distribution falls very close to the central dominant (cD) galaxy and there is substructure near the centre suggesting that the cluster is not fully relaxed. We also examine the effect on the recovered mass when we include the uncertainties in the redshift of the sources and in the original shape of the sources. Using simulations designed to mimic the data, we identify some biases in our reconstructed mass distribution. We find that the recovered mass is biased toward lower masses beyond 1 arcmin (150 kpc) from the cD galaxy and that in the very centre we may be affected by degeneracy problems. On the other hand, we confirm that the reconstructed mass between 25 and 70 arcsec is a robust, unbiased estimate of the true mass distribution and is compatible with an NFW profile.

(abridged) We investigate the detailed response of gas to the formation of transient and long-lived dynamical structures induced in the early stages of a disk-disk collision, and identify observational signatures of radial gas inflow through a detailed examination of the collision simulation of an equal mass bulge dominated galaxy. Stars respond to the tidal interaction by forming both transient arms and long lived m=2 bars, but the gas response is more transient, flowing directly toward the central regions within about 10^8 years after the initial collision. The rate of inflow declines when more than half of the total gas supply reaches the inner few kpc, where the gas forms a dense nuclear ring inside the stellar bar. The average gas inflow rate to the central 1.8 kpc is \~7 Msun/yr with a peak rate of 17 Msun/yr. The evolution of gas in a bulgeless progenitor galaxy is also discussed, and a possible link to the ``chain galaxy'' population observed at high redshifts is inferred. The evolution of the structural parameters (the asymmetry and concentration) of both stars and gas are studied in detail. Further, a new structural parameter (the compactness parameter K) that traces the evolution of the size scale of the gas relative to the stellar disk is introduced. Non-circular gas kinematics driven by the perturbation of the non-axisymmetric structure can produce distinct emission features in the "forbidden velocity quadrants'' of the position-velocity diagram (PVD). The dynamical mass calculated using the rotation curve derived from fitting the emission envelope of the PVD can determine the true mass to within 20% to 40%. The evolution of the molecular fraction $M_H2/M_(H2 + HI) and the compactness (K) are potential tracers to quantitatively assign the age of the interaction., Comment: 52 pages, 20 figures (9 jpgs), accepted for publication in ApJ Version with all figures at http://cfa-www.harvard.edu/~diono/ms.ps.gz

To evaluate the accuracy of manually and automatically segmented true fast imaging with steady-state precession (FISP) and fast low-angle shot (FLASH) cine magnetic resonance (MR) imaging in the determination of left ventricular (LV) mass.Nine dogs and five pigs underwent cine MR imaging of the entire LV from base to apex. Manual and automatic segmentation times were recorded, and LV masses determined with each were compared with each other and with the true LV mass at autopsy. Estimated mass and true mass at autopsy were compared by calculating the correlation coefficient and the mean difference between the two for each MR sequence and segmentation method.True LV mass at autopsy correlated well with masses determined with manual and automatic contours on true FISP MR images. Mean differences between true LV mass and masses determined from manual contours on true FISP and FLASH images were -0.8 g +/- 2.6 and 3.7 g +/- 6.8, respectively. When manually drawn end-diastolic contours were automatically propagated to end systole, mean differences were 2.0 g +/- 3.6 (P =.05) and 9.1 g +/- 6.5 (P.05) for true FISP and FLASH images, respectively. For automatic contours, mean differences were 10.6 g +/- 8.5 (P.05) and 27.7 g +/- 13.4 (P.05) for true FISP and FLASH images, respectively. Mean automatic segmentation time was six times less than mean manual segmentation time.LV mass was determined most accurately by using manual contours on true FISP images. In these animal models, fully automatic segmentation of true FISP images was performed in one-sixth of the time of manual segmentation and yielded LV masses with a mean error of approximately 5% of true LV mass.

Mass transfer studies were carried out in a bubble column using the chemical method. Catalytic oxidation of sodium sulfite was chosen for the studies and the corresponding specific rates of oxidation were obtained using a stirred cell. Laser Doppler anemometer (LDA) was used to measure the instantaneous velocities in the same stirred cell as well as in bubble columns (100 and 150 mm i.d.). An efficient algorithm based on the multiresolution analysis of the velocity-time data using wavelets was used for the isolation of data belonging to the gas and liquid phases. Eddy isolation model was used for the characterization of the eddy motion including the estimation of the energy dissipation rate. Using the knowledge of eddy motion, a methodology was developed for the prediction of true mass transfer coefficient (k L ) in a stirred cell as well as in bubble columns. The predicted values of k L have been compared with the experimental values obtained by the chemical method.

High-resolution spectroscopic searches for the starlight reflected from close-in extra-solar giant planets have the capability of determining the optical albedo spectra and scattering properties of these objects. When combined with radial velocity measurements they also yield the true mass of the planet. To date, only two such planets have been targeted for reflected-light signals, yielding upper limits on the planets' optical albedos. Here we examine the prospects for future searches of this kind. We present Monte Carlo estimates of prior probability distributions for the orbital velocity amplitudes and planet/star flux ratios of 6 bright stars known to harbour giant planets in orbits with periods of less than 5 days. Using these estimates, we assess the viability of these targets for future reflected-light searches using 4m and 8m-class telescopes., Comment: 7 pages, 14 figures, MNRAS accepted 22 August 2003

Coriolis mass flow meter technology has been touted as the "ideal" flow metering technology, and for many companies such as Procter & Gamble this has often been the case. Coriolis mass flow meter technology is the only commercially available technology that can measure true mass flow for our product streams. Coriolis is the most accurate of the industrial process flow metering technologies. It has no moving mechanical parts to wear out, so its theoretical lifespan is almost infinite. One limitation of Coriolis technology is size - flow meters above a nominal three or four inches become exceedingly large and commensurately expensive. For manufacturers in the area of "specialty chemicals" this is not a concern, as process pipelines in excess of four inches are uncommon. Coriolis technology had some initial teething problems, many of which have been effectively resolved by the vendors over the years. Sensitivity to building and pipeline vibration (both mechanical and hydraulic) initially created significant problems for the technology. The development of dual-tube and other technology advancements have effectively solved this problem. Price has always been an issue for Coriolis mass flow meters - it was a premium technology with a premium price. Several vendors have recently introduced low cost yet high performance Coriolis meters, effectively dealing with this issue.

The subdivision of an engine structure in Statistical Energy Analysis (SEA) was first discussed using an indicator (initial slope ratio) for estimating coupling strength between subsystems. Secondly, the modal density of each subsystem was measured in a fully assembled condition. Finally, some experimental estimation methods for SEA parameters were tested in order to establish a useful method for making experimental SEA models of engine structure. As a result, the use of equivalent or true mass and the decay method leads to a good model over the 630 Hz or 1.6 kHz band.

The density of air was directly measured using a Pt-Ir kilogram prototype and a stainless steel kilogram as buoyancy artifacts (BA) in a balance using an automatic weight exchanger capable of handling four weights. The mass values of two other stainless steel weights as test objects placed on the same weight exchanger were determined by comparing them with the prototype of kilogram and using the air density measured in situ. The in situ BA method produced less uncertainty in obtaining the mass values of test weights than that by the BIPM equation method. The accuracy of the in situ direct determination of the air density could be improved by utilizing a stainless steel BA whose true mass and volume could have been known more accurately. BA then could measure the mass of any object with less uncertainty in situ.

Rotation curves are often used to estimate the mass distribution of spiral galaxies, assuming circular rotation of disks. However, non-circular motions caused by a non-axisymmetric gravitational potential, such as a stellar bar, may disturb the velocity field, resulting in errors in mass estimation, especially in the central regions of galaxies, because the line-of-sight velocity depends on the viewing angles in a non-axisymmetric flow. Observing rotation curves of edge-on galaxies in time-dependent numerical simulations from different viewing angles, we obtain errors in the estimation of galactic mass from the rotation curves. In the most extreme case, the ellipticity of gas orbits is as high as 0.8 in the central regions, even if the bar potential is weak. When rotation curves are defined as the highest velocity envelope of position-velocity diagrams, the mass estimated from the rotation curves is larger than the true mass by a factor of five for 15% of the viewing angles, and the ratio between the apparent mass and true mass is less than six for any viewing angle. The overestimation in mass occurs more frequently than the underestimation., 11 pages, 10 figures, accepted by A&A

Using a redshift survey of 1323 galaxies (1092 new or remeasured) in a region of 95 square degrees centered on the nearby galaxy cluster Abell 2199, we analyze the supercluster containing A2199, A2197, and an X-ray group. The caustic technique accurately reproduces the true mass profiles of simulated simple superclusters (i.e., superclusters where the virial mass of one cluster is 2-10 times the virial mass of all other clusters in the supercluster). We calculate the masses of the two main components of A2197 (A2197W and A2197E) using archival X-ray observations and demonstrate that the A2199 supercluster is simple and thus that the caustic technique should yield an accurate mass profile. The mass profile is uncertain by ~30% within 3 Mpc/h and by a factor of two within 8 Mpc/h and is one of only a few for a supercluster on such large scales. Independent X-ray mass estimates agree with our results at all radii where they overlap. The mass profile strongly disagrees with an isothermal sphere profile but agrees with profiles suggested by simulations. We discuss the interplay of the supercluster dynamics and the dynamics of the bound subclusters. The agreement between the infall mass profile and other techniques shows that the caustic technique is surprisingly robust for simple superclusters (abridged)., 49 pages, 20 figures, to appear in The Astronomical Journal, version containing high-resolution figures available at http://cfa-www.harvard.edu/~krines/a2199mp.ps

A wetted-wall cylindrical flow reactor was used to measure uptake coefficients, gamma, of O-3 on aqueous surfaces at 293 K. The loss of O-3 from the gas-phase following contact with varying areas of aqueous surface was determined by UV absorption. The use of Na2S2O3 as an aqueous-phase scavenger for O-3 ensured that uptake coefficients were in a reaction-controlled rather than mass accommodation-controlled regime. Observed uptake coefficients were corrected for radial gas-diffusion to yield values of gamma(corr). From extrapolation of a plot of 1/gamma(corr) against the inverse square-root of the Na2S2O3 activity, a value of alpha = 4 x 10(-2) was derived for the true mass accommodation coefficient of O-3. Evaluation of uncertainties indicate a conservative lower limit of 10(-2) for alpha The data do not rule out that the upper limit approaches unity. However, it is shown that the measured value of alpha is sufficiently high that mass accommodation does not limit heterogeneous processing of O-3 in the atmosphere for droplets of diameter >10 mum. A value of 3.7-0.6+0.7 x 10(8) L mol(-1) s(-1) is derived for the aqueous-phase reaction rate coefficient between O-3 and Na2S2O3 at 293 K.

Doppler spectroscopy of r 1 Cnc has detected evidence of a companion with an orbital period of 14.65 days and a minimum mass of 0.88 Jupiter masses. Astrometric observations performed with the Hubble Space Telescope Fine Guidance Sensor 1r using a novel observing technique have placed an upper limit on the astrometric reflex motion of r 1 Cnc in a time period of only 1 month. These observations detected no reflex motion induced by the 14.65 day period radial velocity companion, allowing us to place a 3 j upper limit of ∼0.3 mas on the semimajor axis of this motion, ruling out the preliminary Hipparcos value of 1.15 mas. The corresponding upper limit on the true mass of the companion is ∼30 MJ, confirming that it is a substellar object. Subject headings: astrometry — planetary systems — stars: low-mass, brown dwarfs

During 2011 February 13 to 15, three Earth-directed CMEs launched in successively were recorded as limb CMEs by coronagraphs (COR) of STEREO. These CMEs provided an opportunity to study their geometrical and kinematic evolution from multiple vantage points. In this paper, we examine the differences in geometrical evolution of slow and fast speed CMEs during their propagation in the heliosphere. We also study their interaction and collision using STEREO/SECCHI COR and Heliospheric Imager (HI) observations. We have found evidence of interaction and collision between the CMEs of February 15 and 14 in COR2 and HI1 FOV, respectively, while the CME of February 14 caught the CME of February 13 in HI2 FOV. By estimating the true mass of these CMEs and using their pre and post-collision dynamics, the momentum and energy exchange between them during collision phase are studied. We classify the nature of observed collision between CME of February 14 and 15 as inelastic, reaching close to elastic regime. Relating imaging observations with the in situ measurements, we find that the CMEs move adjacent to each other after their collision in the heliosphere and are recognized as distinct structures in in situ observations by WIND spacecraft at L1. Our results highlight the significance of HI observations in studying CME-CME collision for the purpose of improved space weather forecasting., 40 pages, 11 figures, accepted for publication in the Astrophysical Journal

We select a chemical magnetohydrodynamic simulation of molecular cloud formation and evolution as a typical example of a Galactic molecular cloud. Its analysis helps us understand how to interpret temperatures and densities inferred from CO line emission maps. We find that the kinetic temperature is always underestimated if it is inferred only from the excitation temperature, T ex, of the12CO(1–0) emission line. We find also that CO primarily traces material at densities above the mean cloud density. In addition, we show that if one assumes a fixed value for the CO–H2 conversion factor, then one will underestimate the density (and hence the mass) of H2 at low column densities. In this scenario, the total H2 mass of the cloud inferred from the emission map is only 60 % of the true mass.

We revisit mass determination techniques for the minimum symmetric event topology, namely $X$ pair production followed by $X \to \ell N$, where $X$ and $N$ are unknown particles with the masses to be measured, and $N$ is an invisible particle, concentrating on the case where $X$ is pair produced from a resonance. We consider separate scenarios, with different initial constraints on the invisible particle momenta, and present a systematic method to identify the kinematically allowed mass regions in the $(m_N, m_X)$ plane. These allowed regions exhibit a cusp structure at the true mass point, which is equivalent to the one observed in the $m_{T2}$ endpoints in certain cases. By considering the boundary of the allowed mass region we systematically define kinematical variables which can be used in measuring the unknown masses, and find a new expression for the $m_{T2}$ variable as well as its inverse. We explicitly apply our method to the case that $X$ is pair produced from a resonance, and as a case study, we consider the process $pp \to A \to \tilde \chi_1^+ \tilde \chi_1^-$, followed by $\tilde \chi_1^\pm \to \ell^{\pm} \, \tilde \nu_{\ell}$, in the Minimal Supersymmetric Standard Model and show that our method provides a precise measurement of the chargino and sneutrino masses, $m_X$ and $m_N$, at $14 \, \mathrm{TeV}$ LHC with $300 \, \mathrm{fb}^{-1}$ luminosity., Comment: 18 pages, 13 figures, version 2 updated to JHEP 06 (2014) 175

We present spectra of the extended 12CO and 13CO J=1-0 emission along the major axes of 17 nearby galaxies. Spatial variations in the ratio of CO and 13CO integrated intensities, R, are found in nearly every galaxy observed. There is an overall variation in R of 20-40% from the inner 2 kpc to the disk. Roughly a third of the survey galaxies have such gradients in R detected above the 2-sigma confidence level. Though some galaxies show a lower central value of R, on average R inside 2 kpc is 10-30% higher than R outside of 2 kpc. An increase in the CO/13CO intensity ratio from disk to nucleus may imply that the conversion factor between CO intensity and H2 column density, X, is lower in galactic nuclei. Also variations in physical conditions, most notably the gas kinetic temperature, affect both R and X. Abundance variations probably do not cause the gradient in R, though we do not rule out a decrease in effective cloud column densities in galactic nuclei possibly caused by destructive starburst superwinds. A modest rise in temperature (less than a factor of 2 or 3) from outside a 2 kpc radius towards the nucleus can easily account for the observed gradient. These results support previous work implying that X is lower in the center of the Milky Way and probably most galactic nuclei. Therefore calculating H2 masses using the standard Galactic X-factor, especially within the central few kpc of galaxies, overestimates the true mass by factors of a few. The standard X-factor still appears to be appropriate for galactic disks.

Twenty-one explanted fixed hearts (14 dogs and 7 pigs) were examined to validate newly developed real-time three-dimensional (RT3D) echocardiography for measurement of left ventricular (LV) mass in vitro and to compare its accuracy and variability with those of conventional echocardiographic measurements. There was an excellent correlation and high degree of agreement for the determination of LV mass between RT3D echocardiography and true mass measurement (r = 0.98; standard error of the estimate [SEE] = 7.3 g; absolute difference [AD] = 2.8 g; y = 1.00 x -4.0, interobserver variability; 5.0%). The conventional echocardiographic methods yielded weaker correlations, larger standard errors, and interobserver variability (area-length method: r = 0.90; SEE = 13.3 g; AD = 13.2 g; 13.3 % / truncated ellipsoid method: r = 0.91; SEE = 14.7 g; AD = 10.5 g; 7. 9% / M-mode: r = 0.91; SEE = 16.2 g; AD = 9.4 g; 15.3%). Determination of LV mass by RT3D echocardiography has a high degree of accuracy and is superior to conventional one- and two-dimensional echocardiographic methods.

Two-dimensional contrast echocardiography has been shown to enable the evaluation of myocardial perfusion abnormalities. However, its ability to quantify a regional myocardial mass is limited. The goal of this study was to examine the quantitative value of 3-dimensional echocardiography (3DE) in the estimation of myocardial mass at risk, salvaged mass, and residual infarct mass after intravenous injection of contrast. We created acute coronary occlusion, followed by reperfusion in 10 dogs. Three-dimensional echocardiographic data were acquired at the end of each stage, and the perfusion defect mass and dysfunctional mass were measured. The true mass at risk and infarct mass were determined by anatomic methods. The anatomic mass at risk (x) (27.1+/-14.6 g or 23.8%+/-9.7% of the left ventricle [%LV]) correlated well with the 3DE-determined perfusion defect mass (y) during coronary occlusion (y = 0.5x+8.9; r = 0.90; P.001; mean difference -4.8+/-8.1 g; or y = 0.7x + 6.5; r = 0.83, P.01; mean difference -0.1+/-5.4 %LV). Good correlation was also found between the anatomic infarct mass (x) (9.3+/-8.1 g or 9.1+/-8.8 %LV) and the 3DE perfusion defect mass after reperfusion (y) (y = 1.2x+1.2; r = 0.93; P.001; mean difference 2.3+/-4.0 g; or y = 1. 3x, r = 0.98, P.0001; mean difference 2.7+/-3.7 %LV). The salvaged mass was 13.6 +/-11.0 %LV from anatomic methods and 14.2+/-13.0 %LV by 3DE. To conclude, with the use of intravenous contrast, 3DE could quantify the actual mass at risk during acute ischemia, and in the setting of reperfusion, the residual infarct mass and salvaged mass.

Step-oblique mammography is a technique used to determine with confidence whether a mammographic finding visible on multiple images on only one projection (but not elucidated using standard additional mammographic projections such as the roll view) represents a summation artifact or a true mass, and to precisely localize the true mass for further evaluation (if applicable). This paper describes the step-oblique technique and evaluates its efficacy.Between January 1, 1993 and December 31, 1998, 69 consecutive women underwent step-oblique mammography for the evaluation of densities seen on multiple images in only one standard projection. Additional images were obtained at 15 degrees stepped increments in obliquity. If a one-projection-only finding was not seen on step-oblique images, the density was judged to represent a summation artifact, completing the examination. If a density was visualized and could be triangulated concordantly on step-oblique images ranging from the craniocaudal to the 90 degrees lateral projection, then it was judged to represent a real lesion. Such a lesion was further characterized (mass, neodensity, architectural distortion, focal asymmetric density) and was localized precisely in three dimensions, permitting imaging-guided tissue diagnosis, if appropriate. For all study patients, we also recorded BI-RADS (American College of Radiology Breast Imaging and Data Reporting System) assessment categories; pathology results for biopsied lesions; and mammographic follow-up, clinical follow-up, and linkage to regional tumor registry for nonbiopsied lesions for which at least 2 years had elapsed since step-oblique mammography.Step-oblique mammography differentiated 50 real lesions from 19 summation artifacts. All 50 real lesions, although initially visible on only one standard projection, were successfully localized in three dimensions. Subsequent management resulted in the prompt detection and diagnosis of seven breast cancers and 21 benign lesions. None of the remaining findings managed by follow-up rather than biopsy have subsequently been found to be malignant.Step-oblique mammography is an effective means of evaluating the mammographic finding visible on multiple images on only one standard projection.

Background: The reproducibility of left ventricular (LV) mass measurement by two-dimensional (2-D) echocardiography is inadequate for individual assessments. Hypothesis: This study was undertaken to evaluate the potential of LV mass determination with a new three-dimensional (3-D) echocardiographic method compared with 2-D measurement. Methods: Porcine agarose-filled left ventricles (n = 15, true mass 61–511 g) of different shapes were measured by a multiplane 3-D method based on 90 images acquired by probe rotation axis (1) perpendicular and (2) parallel to the ventricular long axis [“parasternal” (the left sternal border was not present as a reference point in this study) and apical views]. Mass was also obtained using (3) the biplane truncated ellipsoid and (4) area-length methods, as well as (5) the modified cube formula. Five hearts were not analyzed with the apical 3-D technique because of insufficient image quality. Results: Systematic deviation from true mass was small with all methods (< 5.3%). Accuracy, expressed as 1 standard deviation of individual estimates around this systematic bias, was 7.7, 13.6, 8.2, 11.9, and 11.9% of true mass for the methods 1–5, respectively. Interobserver reproducibility, expressed as the coefficient of variation, was 4.7, 8.8, 8.1, 8.9, and 9.4% for the same methods. Conclusion: Limits for individual accuracy and reproducibility of LV mass estimates are nearly doubled using apical compared with “parasternal” 3-D echocardiography in vitro. A main advantage of “parasternal” 3-D compared with 2-D LV mass estimates is better reproducibility, but at the expense of greater time consumption. Apical 3-D technique is not superior to simpler 2-D methods based on “parasternal” short axis imaging.

Three-dimensional echocardiography has demonstrated superiority over two-dimensional techniques in the determination of left ventricular mass and volumes. We describe a technique based on a magnetic tracking system which provides rapid three-dimensional image acquisition from multiple acoustic windows. Interactive three-dimensional border tracing and reconstruction with a piecewise smooth subdivision model accurately reproduced phantom volume (calculated volume = 1.00 true volume – 0.6 ml, r = 1.000, standard error of the estimate = 1.3 ml), in vitro heart volume (calculated volume = 1.02 true volume – 1.3 ml, r = 1.000, standard error of the estimate = 0.4 ml), in vitro heart mass (calculated mass = 0.98 true mass + 1.4 gm, r = 0.998, standard error of the estimate = 2.5 gm), and in vivo stroke volume (calculated stroke volume = 1.18 Doppler stroke volume – 17.9 ml, r = 0.990, standard error of the estimate = 2.8 ml). The three-dimensional in vivo data sets, which include views from three acoustic windows, were acquired in less than 90 seconds. We conclude that this method of three-dimensional echocardiographic data acquisition and analysis overcomes limitations inherent in currently available systems. (J Am Soc Echocardiogr 1997;10:830-9.)

Objectives. We sought to validate freehand three-dimensional echocardiography for measuring left ventricular mass and to compare its accuracy and variability with those of conventional echocardiographic methods. Background. Accurate measurement of left ventricular mass is clinically important as a predictor of morbidity and mortality. Freehand three-dimensional echocardiography eliminates geometric assumptions used by conventional methods, minimizes image positioning errors using a line of intersection display and increases sampling of the ventricle. Preliminary studies have shown it to have high accuracy and low variability. Methods. Twenty-eight patients awaiting heart transplantation were examined by conventional and freehand three-dimensional echocardiography. Left ventricular mass was determined by the M-mode (“Penn-cube”) method, the two-dimensional truncated ellipsoid method and three-dimensional surface reconstruction. The ventricles of 20 explanted hearts were obtained, trimmed and weighed. Echocardiographic mass by each method was compared with true mass by linear regression. Accuracy, bias and interobserver variability were calculated. Results. For three-dimensional echocardiography, the correlation coefficient, standard error of the estimate, root mean square percent error (accuracy), bias and interobserver variability were 0.992, 11.9 g, 4.8%, −4.9 g and 11.5%, respectively. For the two-dimensional truncated ellipsoid method they were 0.905, 38.5 g, 15.6%, 15.4 g and 23.3%. For the M-mode (“Penn-cube”) method they were 0.721, 96.9 g, 53.0%, 109.2 g and 19.5%. Conclusions. Freehand three-dimensional echocardiography for measurement of left ventricular mass has high accuracy and low variability and is superior to conventional methods in hearts of abnormal size and geometry.

The mass fraction of dense gas within giant molecular clouds (GMCs) of the Milky Way is investigated using 13CO data from the FCRAO Galactic Plane Surveys and the Bolocam Galactic Plane Survey (BGPS) of 1.1 mm dust continuum emission. A sample of 860 compact dust sources are selected from the BGPS catalog and kinematically linked to 344 clouds of extended (>3') 13CO J=1-0 emission. Gas masses are tabulated for the full dust source and subregions within the dust sources with mass surface densities greater than 200 M_solar/pc^2, which are assumed to be regions of enhanced volume density. Masses of the parent GMCs are calculated assuming optically thin 13CO J=1-0 emission and LTE conditions. The mean fractional mass of dust sources to host GMC mass is 0.11 (-0.06, +0.12). The high column density subregions comprise 0.07 (-0.05, +0.13) of the mass of the cloud. Owing to our assumptions, these values are upper limits to the true mass fractions. The fractional mass of dense gas is independent of GMC mass and gas surface density. The low dense gas mass fraction suggests that the formation of dense structures within GMCs is the primary bottleneck for star formation. The distribution of velocity differences between the dense gas and the low density material along the line of sight is also examined. We find a strong, centrally peaked distribution centered on zero velocity displacement. This distribution of velocity differences is modeled with radially converging flows towards the dense gas position that are randomly oriented with respect to the observed line of sight. These models constrain the infall velocities to be 2-4 km/s for various flow configurations., 12 pages, 6 figures, 1 table. Accepted for publication in ApJ

Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85 (+0.52,-0.42) M_Jupiter, which implies that it is a planet, not a brown dwarf., Comment: Published in Proceedings of the National Academy of Sciences (5 pages, 5 figures, 3 tables). Available at http://www.pnas.org/cgi/doi/10.1073/pnas.1303291110

We present a new approach with which the dynamical mass of low-mass companions around cool stars can be found. In order to discover companions to late-type stars the stellar spectrum is removed. For this we substract two spectra obtained at different orbital phases from each other in order to discover the companion spectrum in the difference spectrum in which the companion lines appear twice (positive and negative signal). The resulting radial velocity difference of these two signals provides the true mass of the companion. For our test case GJ1046, an M2V dwarf with a low-mass companion that most likely is a brown dwarf we select the CO line region in the K-band. We show that the dynamical mass of a faint companion to an M dwarf can be determined using our spectral differential technique. Only if the companion rotates rapidly and has a small radial velocity amplitude due to a high mass, does blending occur for all lines so that our approach fails. In addition to determining the companion mass, we restore the single companion spectrum from the difference spectrum using singular value decomposition.

We examine the validity of the hydrostatic equilibrium (HSE) assumption for galaxy clusters using one of the highest-resolution cosmological hydrodynamical simulations. We define and evaluate several effective mass terms corresponding to the Euler equations of the gas dynamics, and quantify the degree of the validity of HSE in terms of the mass estimate. We find that the mass estimated under the HSE assumption (the HSE mass) deviates from the true mass by up to ~ 30 %. This level of departure from HSE is consistent with the previous claims, but our physical interpretation is rather different. We demonstrate that the inertial term in the Euler equations makes a negligible contribution to the total mass, and the overall gravity of the cluster is balanced by the thermal gas pressure gradient and the gas acceleration term. Indeed the deviation from the HSE mass is well explained by the acceleration term at almost all radii. We also clarify the confusion of previous work due to the inappropriate application of the Jeans equations in considering the validity of HSE from the gas dynamics extracted from cosmological hydrodynamical simulations., Comment: 14 pages, 8 figures, to appear in ApJ

Typically, when estimating the prior transit probability, one assumes a uniform distribution for the cosine of the inclination angle i of the companion's orbit, which yields the familiar estimate of ~R_*/a. However, the posterior transit probability depends not only on the prior probability distribution of i but also on the prior probability distribution of the companion mass M_c. In general, the posterior can be larger or smaller than the prior transit probability. We derive analytic expressions for the posterior transit probability assuming a power-law form for the distribution of true masses with exponent alpha. For low transit probabilities, these probabilities reduce to a constant multiplicative factor of the corresponding prior transit probability. The prior and posterior probabilities are equal for alpha = -1, whereas the posterior transit probability is ~1.5 times larger and ~4/pi larger for for alpha = -3 and alpha = -2, but is less than the prior for alpha >= 0, and can be arbitrarily small for alpha > 1. We also calculate the posterior transit probability in different mass regimes for two physically-motivated mass distributions of companions around Sun-like stars, finding that the posterior is likely higher for Super-Earths, Neptunes and Super-Jupiters. We therefore suggest that companions with minimum masses in these regimes might be better-than-expected targets for transit follow-up, and we identify promising targets from RV-detected planets in the literature., 18 pages, 10 figures. For a brief video highlighting the key results of this paper, see http://youtu.be/q72xoLbCCVU

The arterial blood vessel system of kidneys is known to be fractal with a global mass dimension of 2.2 to 2.3. The global mass dimensions were determined by the mass-radius method.1 We support these results of the mass correlation analysis with an examination of the surface, which is in good approximation with the "true mass" of the border between the tissue (parenchyma) and the blood. We applied the Minkowski cover to the vessel surfaces and determined their scaling behavior, which yielded the surface global dimension. The examinations on kidney arteries1 are supplemented with new data of placentoma arteries2 and a comparison is made between their surface and mass dimensions.

[1] The Gravity Recovery And Climate Experiment (GRACE) mission has been providing high quality observations since its launch in 2002. Over the years, fruitful achievements have been obtained and the temporal gravity field has revealed the ongoing geophysical, hydrological and other processes. These discoveries help the scientists better understand various aspects of the Earth. However, errors exist in high degree and order spherical harmonics, which need to be processed before use. Filtering is one of the most commonly used techniques to smooth errors, yet it attenuates signals and also causes leakage of gravity signal into surrounding areas. This paper reports a new method to estimate the true mass change on the grid (expressed in equivalent water height or surface density). The mass change over the grid can be integrated to estimate regional or global mass change. This method assumes the GRACE-observed apparent mass change is only caused by the mass change on land. By comparing the computed and observed apparent mass change, the true mass change can be iteratively adjusted and estimated. The problem is solved with nonlinear programming (NLP) and yields solutions which are in good agreement with other GRACE-based estimates.

International audience; Context. The photometric signal we receive from a star hosting a planet is modulated by the variation in the planet signal with its orbital phase. Such phase variations (or phase curves) are observed for transiting hot Jupiters with current instrumentation and have also been measured for one transiting terrestrial planet (Kepler10b) and one nontransiting gas giant (Ups A b). Future telescopes (JWST and EChO) will have the capability of measuring thermal phase curves of exoplanets, including hot rocky planets in transiting and nontransiting configurations and at different wavelengths. Short-period planets with a mass below 10 R⊕ are indeed frequent, and nearby targets (within 10 pc) are already known and more are to be found. Aims: We test the possibility of using multiwavelength infrared phase curves to constrain the radius, the albedo, and the orbital inclination of a nontransiting planet with no atmosphere and on a 1:1 spin orbit resonance. Methods: We modeled the thermal emission of a synchronous rocky planet with no atmosphere and its apparent variation with the orbital phase for a given orbital inclination. We assume that the planet is detected by radial velocity so its orbital period and minimum mass are known. We simulated observed noisy phase curves and then applied an optimization procedure to retrieve the radius and albedo of the planet and the inclination of the orbit. Results: Airless planets can be distinguished from planets having a dense atmosphere and their radius, albedo, and inclination (and therefore true mass) can be retrieved from multiband observations with MIRI-JWST and EChO in the 5-15 μm range. The accuracy depends on stellar type, orbital distance, radius of the planet and inclination: hot and large planets on highly inclined orbit are favored. As inclination above 60° represents half of the randomly oriented orbits, the growing population of short-period, terrestrial-sized planets detected by radial velocity surveys and transits should offer several nearby promising targets for this method, including planets GJ581 e, b, and HD 40307 b. Conclusions: Stellar activity is likely to limit the accuracy of this method, at least for some stars. It has not been taken into account in this study, and its effects will have to be addressed in future works.

Context. The {\beta} Pictoris system with its debris disk and a massive giant planet orbiting at \simeq 9 AU represents an ideal laboratory to study giant planet formation and evolution as well as planet-disk interactions. {\beta} Pic b can also help testing brightness-mass relations at young ages. Other planets, yet undetected, may of course be present in the system. Aims. We aim at putting direct constrains on the mass of {\beta} Pic b and at searching for additional jovian planets on orbits closer than typically 2 AU. Methods. We use high precision Harps data collected over 8 years since 2003 to measure and analyse {\beta} Pic radial velocities. Results. We show that the true mass of {\beta} Pic b is less than 10, 12, 15.5, 20 and 25 MJup if orbiting respectively at 8, 9, 10, 11 and 12 AU. This is the first direct constraint on the mass of an imaged planet. The upper mass found is well in the range predicted by brightness-mass relations provided by current "hot start" models. We also exclude the presence of giant planets more massive than 2.5 MJup with periods less than 100 days (hot Jupiters), more massive than 9 MJup for periods in the range 100-500 days. In the 500-1000 day range, the detection limit is in the brown dwarf domain. Beyond the intrinsic interest for {\beta} Pic, these results show the possibilities of precise RV measurements of early type, rapidly rotating stars., Comment: 6 pages, 9 figures, to appear in Astronomy and Astrophysics