On the use of scaling relations for the Tolman test

The use of relations between structural parameters of early type galaxies to perform the Tolman test is reconsidered. Scaling relations such as the FP or the Kormendy relation, require the transformation from angular to metric sizes, to compare the relation at different z values. This transformation depends on the assumed world model: galaxies of a given angular size, at a given z, are larger (in kpc) in a non-expanding universe than in an expanding one. Furthermore, the luminosities of galaxies are expected to evolve with z in an expanding model. These effects are shown to conspire to reduce the difference between the predicted SB change with redshift in the expanding and non expanding cases. We find that the predictions for the visible photometric bands of the expanding models with passive luminosity evolution are very similar to those of the static model till z about 1, and therefore, the test cannot distinguish between the two world models. Recent good quality data are consistent with the predictions from both models. In the K-band, where the expected (model) luminosity evolutionary corrections are smaller, the differences between the xpanding and static models amount to about 0.4 (0.8) magnitudes at z = 0.4 (1). It is shown that, due to that small difference between the predictions in the covered z-range, and to the paucity and uncertainties of the relevant SB photometry, the existing K-band data is not adequate to distinguish between the different world metrics, and cannot be yet used to discard the static case. It is pointed out that the scaling relations could still be used to rule out the non-evolving case if it could be shown that the coefficients change with the redshift.Comment: Latex, 15 pages with 2 figures. To be published in ApJ Letter

Multiwavelength Energy Distributions and Bolometric Luminosities of the 12--Micron Galaxy Sample

Aperture photometry from our own observations and the literature is presented for the 12\um\ Galaxies in the near infrared J, H and K bands and, in some cases, in the L band. These data are corrected to ``total'' near--infrared magnitudes, (with a typical uncertainty of 0.3 magnitudes) for a direct comparison with our IRAS fluxes which apply to the entire galaxy. The corrected data are used to derive integrated total NIR and FIR luminosities. We then combine these with blue photometry and an estimate of the flux contribution from cold dust at wavelengths longward of 100\um\ to derive the first {\it bolometric\/} luminosities for a large sample of galaxies. We use multiwavelength correlations to identify several combinations of infrared colors which discriminate between Seyfert~1 and~2 galaxies, LINERs, and ultraluminous starbursts. We find that bolometric luminosity is more closely proportional to 12-micron luminosity than to 60-micron, 25-micron or optical luminosity.Comment: AASTeX, 18 pages. Text only. Figures (28) and tables (3) available at ftp://eggneb.astro.ucla.edu/pub/rush/, named Spinoglio95-Table*.dat (ASCII) and Spinoglio95-figs.ps (PostScript; 7 pages, by 4 per page). Scheduled for the 1995 November 10 issue of Ap

Near-Infrared Imaging of Early-Type Galaxies III. The Near-Infrared Fundamental Plane

Near-infrared imaging data on 251 early-type galaxies in clusters and groups are used to construct the near-infrared Fundamental Plane (FP) r_eff ~ sigma_0^1.53 _eff^-0.79. The slope of the FP therefore departs from the virial expectation of r_eff ~ sigma_0^2 _eff^-1 at all optical and near-infrared wavelengths, which could be a result of the variation of M/L along the elliptical galaxy sequence, or a systematic breakdown of homology among the family of elliptical galaxies. The slope of the near-infrared FP excludes metallicity variations as the sole cause of the slope of the FP. Age effects, dynamical deviations from a homology, or any combination of these (with or without metallicity), however, are not excluded. The scatter of both the near-infrared and optical FP are nearly identical and substantially larger than the observational uncertainties, demonstrating small but significant intrinsic cosmological scatter for the FP at all wavelengths. The lack of a correlation of the residuals of the near-infrared FP and the residuals from the Mg_2-sigma relation indicates that the thickness of these relations cannot be ascribed only to age or metallicity effects. Due to this metallicity independence, the small scatter of the near-infrared FP excludes a model in which age and metallicity effects ``conspire'' to keep the optical FP thin. All of these results suggest that the possible physical origins of the FP relations are complicated due to combined effects of variations of stellar populations and structural parameters among elliptical galaxies.Comment: to appear in The Astronomical Journal; 35 pages, including 13 Postscript figures and 1 table; uses AAS LaTeX style file

Clues on the Physical Origin of the Fundamental Plane from Self-consistent Hydrodynamical Simulations

We report on a study of the parameters characterizing the mass and velocity distributions of two samples of relaxed elliptical-like objects (ELOs) identified, at z=0, in a set of self-consistent hydrodynamical simulations operating in the context of a concordance cosmological model. Star formation (SF) has been phenomenologically implemented in the simulations in the framework of the turbulent sequential scenario through a threshold gas density and an efficiency parameter. Each ELO sample is characterized by the values these parameters take. We have found that the (logarithms of the) ELO stellar masses, projected stellar half-mass radii, and stellar central line-of-sight (LOS) velocity dispersions define dynamical fundamental planes (FPs). Zero points depend on the particular values that the SF parameters take, while slopes do not change. The ELO samples have been found to show systematic trends with the mass scale in both the relative content and the relative distributions of the baryonic and the dark mass ELO components. The physical origin of these trends lies in the systematic decrease, with increasing ELO mass, of the relative dissipation experienced by the baryonic mass component along ELO mass assembly, resulting in a tilt of the dynamical FP relative to the virial plane. The dynamical FPs shown by the two ELO samples are consistent with that shown by the SDSS elliptical sample in the same variables, with no further need for any relevant contribution from stellar population effects to explain the observed tilt. These effects could, however, have contributed to the scatter of the observed FP, as the dynamical FPs have been found to be thinner than the observed one. The results we report on hint, for the first time, at a possible way to understand the tilt of the observed FP in a cosmological context.Comment: 12 pages, 1 figure. Accepted to Astrophysical Journal Letter

The Near-Infrared Fundamental Plane of Elliptical Galaxies

We present results from a near-infrared $K$-band imaging survey of 59 elliptical galaxies in five nearby clusters. We measure photometric parameters for each galaxy using surface photometry and draw velocity dispersions from the literature. Three observables define a near-infrared Fundamental Plane (FP) of elliptical galaxies with $R_e \propto \sigma^{1.44\pm0.04} \Sigma_e^{-0.79\pm0.04}$. The scatter in the near-infrared relation is small at $16.5$\% in distance, which is equivalent to, or less than, the scatter of the optical FP. We suggest that the small deviation of the near-infrared FP relation from the optical FP is due to the reduction of metallicity effects in the near-infrared bandpass. While the small scatter of the optical FP could be consistent with compensating effects of age and metallicity, the similarly small scatter of the near-infrared FP is nearly independent of metallicity and hence places a strong constraint on possible age spreads among elliptical galaxies at every point along the FP. We suggest that the departure of the near-infrared FP from the pure virial form $R_e \propto \sigma^2 \Sigma_e^{-1}$, and the corresponding observed relation $\left( M/L \right) \propto M^{0.16\pm 0.01}$, may be explained by slight systematic departures of the structure and dynamics of elliptical galaxies from a homology.Comment: to appear in The Astrophysical Journal (Letters); 12 pages, including 2 Postscript figures and 1 table; uuencoded, compressed format; the paper is also available in various formats from http://astro.caltech.edu/~map/map.bibliography.refereed.htm

Unresolved H-Alpha Enhancements at High Galactic Latitude in the WHAM Sky Survey Maps

We have identified 85 regions of enhanced H-Alpha emission at |b| > 10 degrees subtending approximately 1 degree or less on the Wisconsin H-Alpha Mapper (WHAM) sky survey. These high latitude ``WHAM point sources'' have H-Alpha fluxes of 10^{-11} to 10^{-9} erg cm^-2 s^-1, radial velocities within about 70 km/s of the LSR, and line widths that range from less than 20 km/s to about 80 km/s (FWHM). Twenty nine of these enhancements are not identified with either cataloged nebulae or hot stars and appear to have kinematic properties that differ from those observed for planetary nebulae. Another 14 enhancements are near hot evolved low mass stars that had no previously reported detections of associated nebulosity. The remainder of the enhancements are cataloged planetary nebulae and small, high latitude H II regions surrounding massive O and early B stars.Comment: 22 pages, 8 figures, 2 tables, to appear in Feb. 2005 A

Effect of the Milky Way on Magellanic Cloud structure

A combination of analytic models and n-body simulations implies that the structural evolution of the Large Magellanic Cloud (LMC) is dominated by its dynamical interaction with the Milky Way. Although expected at some level, the scope of the involvement has significant observational consequences. First, LMC disk orbits are torqued out of the disk plane, thickening the disk and populating a spheroid. The torque results from direct forcing by the Milky Way tide and, indirectly, from the drag between the LMC disk and its halo resulting from the induced precession of the LMC disk. The latter is a newly reported mechanism that can affect all satellite interations. However, the overall torque can not isotropize the stellar orbits and their kinematics remains disk-like. Such a kinematic signature is observed for nearly all LMC populations. The extended disk distribution is predicted to increase the microlensing toward the LMC. Second, the disk's binding energy slowly decreases during this process, puffing up and priming the outer regions for subsequent tidal stripping. Because the tidally stripped debris will be spatially extended, the distribution of stripped stars is much more extended than the HI Magellanic Stream. This is consistent with upper limits to stellar densities in the gas stream and suggests a different strategy for detecting the stripped stars. And, finally, the mass loss over several LMC orbits is predicted by n-body simulation and the debris extends to tens of kiloparsecs from the tidal boundary. Although the overall space density of the stripped stars is low, possible existence of such intervening populations have been recently reported and may be detectable using 2MASS.Comment: 15 pages, color Postscript figures, uses emulateapj.sty. Also available from http://www-astro.phast.umass.edu/~weinberg/weinberg-pubs.htm

Vasorelaxant activity of Euphorbia furcillata Kunth mainly by activation of NO/cGMP pathway and calcium channel blockade

The aim of current study was to determinate ex vivo and chromatographic fingerprint by HPLC of four extracts of Euphorbia furcillata K. Ethyl acetate extract of Euphorbia furcillata (EaEEf) was the most effective and potent extract (Emax=98.69±1.24%) and its effect was partially endothelium-dependent. Functional vasorelaxant mechanism of action of EaEEf was determinate, EaEEf showed efficient relaxation of KCl [80 mM]-induced contraction and norepinephrine and CaCl2 contraction curves showed diminution of maximal contraction in the presence of EAEEf and EaEEf-relaxation curve was shifted to the right in the presence of L-NAME (nitric oxide synthase inhibitor) and ODQ (guanylate cyclase inhibitor). Chromatographic fingerprints analysis suggests presence of diterpenoid such as abietane, tigliane, and ingenane skeletons. Our experiments suggest the EaEEf vasorelaxant activity could be attributed to diterpenoid molecules whose mechanism involves nitric oxide production and calcium channel blockade

Stellar streams around the Magellanic Clouds

Using Blue Horizontal Branch stars identified in the Dark Energy Survey Year 1 data, we report the detection of an extended and lumpy stellar debris distribution around the Magellanic Clouds. At the heliocentric distance of the Clouds, overdensities of BHBs are seen to reach at least to ~30 degrees, and perhaps as far as ~50 degrees from the LMC. In 3D, the stellar halo is traceable to between 25 and 50 kpc from the LMC. We catalogue the most significant of the stellar sub-structures revealed, and announce the discovery of a number of narrow streams and diffuse debris clouds. Two narrow streams appear approximately aligned with the Magellanic Clouds' proper motion. Moreover, one of these overlaps with the gaseous Magellanic Stream on the sky. Curiously, two diffuse BHB agglomerations seem coincident with several of the recently discovered DES satellites. Given the enormous size and the conspicuous lumpiness of the LMC's stellar halo, we speculate that the dwarf could easily have been more massive than previously had been assumed.Comment: 15 pages, 11 figures. Figures improved. Accepted to MNRA

N-body simulations of the Magellanic Stream

A suite of high-resolution N-body simulations of the Magellanic Clouds -- Milky Way system are presented and compared directly with newly available data from the HI Parkes All-Sky Survey (HIPASS). We show that the interaction between Small and Large Magellanic Clouds results in both a spatial and kinematical bifurcation of both the Stream and the Leading Arm. The spatial bifurcation of the Stream is readily apparent in the HIPASS data, and the kinematical bifurcation is also tentatively identified. This bifurcation provides strong support for the tidal disruption origin for the Magellanic Stream. A fiducial model for the Magellanic Clouds is presented upon completion of an extensive parameter survey of the potential orbital configurations of the Magellanic Clouds and the viable initial boundary conditions for the disc of the Small Magellanic Cloud. The impact of the choice of these critical parameters upon the final configurations of the Stream and Leading Arm is detailed.Comment: Accepted by MNRAS, 07 Jun 2006. 14 pages, 14 figures, 3 tables. LaTeX (mn2e.sty). File with decent resolution images (strongly recommended) available at http://astronomy.swin.edu.au/~tconnors/publications/ . References added; distance and HI-LOres difference figures added; clearer figures; discussion added to, but conclusions unchange