Abstract. We present calibrations of the effective temperatures of giant stars versus [Fe/H] and colours (U. These calibrations are based on a large sample of field and globular cluster stars which roughly cover spectral types from F0 to K5. Their effective temperatures, scaled to direct T eff determinations via reliable angular diameter measurements, were derived by applying the infrared flux method. The empirical relations have been fitted to polynomials of the form θ eff = P (colour, [Fe/H]) by using the least squares method. The precision of the fits ranges from 40 K for (V −K) to 170 K for (J −H). We tabulate intrinsic colours of giant stars in the ranges: 3500 K ≤ T eff ≤ 8000 K; −3.0 ≤ [Fe/H] ≤ +0.5. We also present the calibration of BC(V) as a function of log(T eff ) and metallicity. Finally, we compare the resulting scale of temperatures with previous works.
We study the kinematic properties of the ionised gas outflows and ambient interstellar medium (ISM) in a large and representative sample of local luminous and ultra-luminous infrared galaxies (U/LIRGs) (58 systems, 75 galaxies) at galactic and sub-galactic (i.e., star-forming clumps) scales, thanks to integral field spectroscopy (IFS)-based high signal-to-noise integrated spectra. The velocity dispersion of the ionized ISM in U/LIRGs ( σ ∼ 70 km s −1 ) is larger than in lower luminosity local star-forming galaxies ( σ ∼ 25 km s −1 ). While for isolated disc LIRGs star formation appears to sustain turbulence, gravitational energy release associated with interactions and mergers plays an important role in driving σ in the U/LIRG range. We find that σ has a dependency on the star formation rate density (Σ SFR ), which is weaker than expected if it were driven by the energy released by the starburst. The relatively small role of star formation (SF) driving the σ in U/LIRGs is reinforced by the lack of an increase in σ associated with high luminosity SF clumps. We also find that the impact of an active galactic nucleus (AGN) in ULIRGs is strong, increasing on average σ by a factor 1.5. Low-z U/LIRGs cover a range of velocity dispersion (σ ∼ 30 to 100 km s −1 ) and star formation rate density (Σ SFR ∼ 0.1 to 20 M yr −1 kpc −2 ) similar to those of high-z SFGs. Moreover, the observed weak dependency of σ on Σ SFR for local U/LIRGs (σ ∝ Σ +0.06 SFR ) is in very good agreement with that measured in some high-z samples. The presence of ionized gas outflows in U/LIRGs seems universal based on the detection of a broad, usually blueshifted, Hα line. The observed dependency of the maximum velocity of the outflow (V max ) on the star formation rate (SFR) is of the type+0.24 . We find that AGNs in U/LIRGs are able to generate faster (∼×2) and more massive (∼× 1.4) ionized gas outflows than pure starbursts. The derived ionized mass loading factors (η) are in general below 1, with only a few AGNs above this limit. The escaping gas fraction is low with only less massive (log(M dyn /M ) < 10.4) U/LIRGs having outflowing terminal velocities higher than their escape velocities, and more massive galaxies retaining the gas, even if they host an AGN. The observed average outflow properties in U/LIRGs are similar to high-z galaxies of comparable SFR. However, while high-z galaxies seem to require Σ SFR > 1 M yrfor launching strong outflows, this threshold is not observed in low-z U/LIRGs even after correcting for the differential fraction of the gas content. In the bright SF clumps found in LIRGs, ionized gas outflows appear to be very common (detection rate over 80%). Their observed properties are less extreme than those associated with the entire galaxy. The clumps in LIRGs follow the general size-L-σ scaling relations found for low-and high-z clumps, though they are in general smaller, less luminous, and are characterized by lower σ than at high-z. For a given observed (no internal extinction correction applied) star formation...
We present a simple set of kinematic criteria that can distinguish between galaxies dominated by ordered rotational motion and those involved in major merger events. Our criteria are based on the dynamics of the warm ionized gas (as traced by H) within galaxies, making this analysis accessible to high-redshift systems, whose kinematics are primarily traceable through emission features. Using the method of kinemetry (developed by Krajnović and coworkers), we quantify asymmetries in both the velocity and velocity dispersion maps of the warm gas, and the resulting criteria enable us to empirically differentiate between nonmerging and merging systems at high redshift. We apply these criteria to 11 of our best-studied rest-frame UV/optical-selected z $ 2 galaxies for which we have near-infrared integralfield spectroscopic data from SINFONI on the VLT. Of these 11 systems, we find that >50% have kinematics consistent with a single rotating disk interpretation, while the remaining systems are more likely undergoing major mergers. This result, combined with the short formation timescales of these systems, provides evidence that rapid, smooth accretion of gas plays a significant role in galaxy formation at high redshift.
Abstract. -We have applied the InfraRed Flux Method (IRFM) to a sample of 475 dwarfs and subdwarfs in order to derive their effective temperatures with a mean accuracy of about 1.5%. We have used the new homogeneous grid of theoretical model atmosphere flux distributions developed by Kurucz (1991Kurucz ( , 1993 for the application of the IRFM. The atmospheric parameters of the stars cover, roughly, the ranges: 3500 K ≤ Teff ≤ 8000 K; −3.5 ≤ [Fe/H] ≤ +0.5; 3.5 ≤ log(g) ≤ 5. The monocromatic infrared fluxes at the continuum, and the bolometric fluxes are derived using recent results, which satisfy the accuracy requeriments of the work. Photometric calibrations have been revised and applied to estimate metallicities, although direct spectroscopic determinations were preferred when available. The adopted infrared absolute flux calibration, based on direct optical measurements of angular stellar diameters, sets the effective temperatures determined using the IRFM on the same scale than those obtained by direct methods. We derive three temperatures, TJ , TH and TK , for each star using the monochromatic fluxes at different infrared wavelengths in the photometric bands J , H, and K. They show good consistency over 4000 K, and no trend with wavelength may be appreciated. We provide a detailed description of the steps followed for the application of the IRFM, as well as the sources of the errors associated to the different inputs of the method, and their transmission into the final temperatures. We also provide comparison with previous works.
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