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Register a new userThe Tully-Fisher relation in dense groups at $z sim 0.7$ in the MAGIC survey
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Galaxies in dense environments are subject to interactions and mechanisms which directly affect their evolution by lowering their gas fractions and reducing their star-forming capacity earlier than their isolated counterparts. The aim of our project is to get new insights about the role of environment on the stellar and baryonic content of galaxies using a kinematic approach, through the study of the Tully-Fisher relation (TFR). We study a sample of galaxies in 8 groups spanning a redshift range of $0.5<z<0.8$ and located in 10 pointings of the MAGIC MUSE Guaranteed Time Observations program. We perform a morpho-kinematics analysis of this sample and set up a selection based on galaxy size, [OII] emission line doublet signal-to-noise ratio, bulge-to-disk ratio and nuclear activity to construct a robust kinematic sample of 67 star-forming galaxies. This selection considerably reduces the number of outliers in the TFR, which are predominantly dispersion-dominated galaxies. Our results suggest a significant offset of the TFR zero-point between galaxies in low- and high-density environments, whatever kinematics estimator is used. This can be interpreted as a decrease of either stellar mass by $sim 0.05 - 0.3$ dex or an increase of rotation velocity by $sim 0.02 - 0.06$ dex for galaxies in groups, depending on the samples used for comparison. We also studied the stellar and baryon mass fractions within stellar disks and found they both increase with stellar mass, the trend being more pronounced for the stellar component alone. These fractions do not exceed 50%. We show that this evolution of the TFR is consistent either with a decrease of star formation or with a contraction of the mass distribution due to the environment. These two effects probably act together with their relative contribution depending on the mass regime.
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Local and intermediate redshift (z~0.5) galaxy samples obey well correlated relations between the stellar population luminosity and maximal galaxy rotation that define the Tully-Fisher (TF) relation. Consensus is starting to be reached on the TF relation at z~0.5, but work at significantly higher redshifts is even more challenging, and has been limited by small galaxy sample sizes, the intrinsic scatter of galaxy properties, and increasing observational uncertainties. We present here the TF measurements of 41 galaxies at relatively high redshift, spectroscopically observed with the Keck/DEIMOS instrument by the DEEP2 project, a survey which will eventually offer a large galaxy sample of the greatest depth and number yet achieved towards this purpose. The first-look sample analyzed here has a redshift range of 0.75<z<1.3 with <z>= 0.85 and an intrinsic magnitude range from M_B of -22.66 to -20.57 (Vega). We find that compared to local fiducial samples, a brightening of 1.5 magnitudes is observed, and consistent with passive evolutionary models.
[abr.] Using the multi-integral-field spectrograph GIRAFFE at VLT, we previsouly derived the stellar-mass Tully-Fisher Relation (smTFR) at z~0.6, and found that the distant relation is systematically offset by roughly a factor of two toward lower masses. We extend the study of the evolution of the TFR by establishing the first distant baryonic TFR. To derive gas masses in distant galaxies, we estimate a gas radius and invert the Schmidt-Kennicutt law between star formation rate and gas surface densities. We find that gas extends farther out than the UV light from young stars, a median of ~30%. We present the first baryonic TFR (bTFR) ever established at intermediate redshift and show that, within an uncertainty of +/-0.08 dex, the zeropoint of the bTFR does not appear to evolve between z~0.6 and z=0. The absence of evolution in the bTFR over the past 6 Gyr implies that no external gas accretion is required for distant rotating disks to sustain star formation until z=0 and convert most of their gas into stars. Finally, we confirm that the larger scatter found in the distant smTFR, and hence in the bTFR, is caused entirely by major mergers. This scatter results from a transfer of energy from bulk motions in the progenitors, to random motions in the remnants, generated by shocks during the merging. Shocks occurring during these events naturally explain the large extent of ionized gas found out to the UV radius in z~0.6 galaxies. All the results presented in this paper support the ``spiral rebuilding scenario of Hammer and collaborators, i.e., that a large fraction of local spiral disks have been reprocessed during major mergers in the past 8 Gyr.
Using moderate-resolution Keck spectra, we have examined the velocity profiles of 15 members of cluster Cl0024+1654 at z=0.4. WFPC2 images of the cluster members have been used to determine structural parameters, including disk sizes, orientations, and inclinations. We compare two methods of optical rotation curve analysis for kinematic measurements. Both methods take seeing, slit size and orientation, and instrumental effects into account and yield similar rotation velocity measurements. Four of the galaxies in our sample exhibit unusual kinematic signatures, such as non-circular motions. Our key result is that the Cl0024 galaxies are marginally underluminous (0.50 +/- 0.23 mag), given their rotation velocities, as compared to the local Tully-Fisher relation. In this analysis, we assume no slope evolution, and take into account systematic differences between local and distant velocity and luminosity measurements. Our result is particularly striking considering the Cl0024 members have very strong emission lines, and local galaxies with similar Halpha equivalent widths tend to be overluminous on the Tully-Fisher relation. Cl0024 Tully-Fisher residuals appear to be correlated most strongly with galaxy rotation velocities, indicating a possible change in the slope of the Tully-Fisher relation. However, we caution that this result may be strongly affected by magnitude selection and by the original slope assumed for the analysis. Cl0024 residuals also depend weakly on color, emission line strength and extent, and photometric asymmetry. In a comparison of stellar and gas motions in two Cl0024 members, we find no evidence for counter-rotating stars and gas, an expected signature of mergers.
We investigate the Tully-Fisher Relation (TFR) for a morphologically and kine- matically diverse sample of galaxies from the SAMI Galaxy Survey using 2 dimensional spatially resolved Halpha velocity maps and find a well defined relation across the stellar mass range of 8.0 < log(M*) < 11.5. We use an adaptation of kinemetry to parametrise the kinematic Halpha asymmetry of all galaxies in the sample, and find a correlation between scatter (i.e. residuals off the TFR) and asymmetry. This effect is pronounced at low stellar mass, corresponding to the inverse relationship between stellar mass and kinematic asymmetry found in previous work. For galaxies with log(M*) < 9.5, 25 +/- 3% are scattered below the root mean square (RMS) of the TFR, whereas for galaxies with log(M*) > 9.5 the fraction is 10 +/- 1% We use simulated slits to directly compare our results with those from long slit spectroscopy and find that aligning slits with the photometric, rather than the kinematic, position angle, increases global scatter below the TFR. Further, kinematic asymmetry is correlated with misalignment between the photometric and kinematic position angles. This work demonstrates the value of 2D spatially resolved kinematics for accurate TFR studies; integral field spectroscopy reduces the underestimation of rotation velocity that can occur from slit positioning off the kinematic axis.
We use KMOS Deep Survey (KDS) galaxies, combined with results from a range of spectroscopic studies in the literature, to investigate the evolution of the stellar-mass Tully-Fisher relation since z ~ 4. We determine the slope and normalisation of the local rotation-velocity -- stellar-mass (Vc - $M_{star}$) relationship using a reference sample of local spiral galaxies; thereafter we fix the slope, and focus on the evolution of velocity normalisation with redshift. The rotation-dominated KDS galaxies at z ~ 3.5 have rotation velocities ~ -0.1 dex lower than local reference galaxies at fixed stellar mass. By fitting 16 distant comparison samples spanning 0 < z < 3 (containing ~ 1200 galaxies), we show that the size and sign of the inferred Vc offset depends sensitively on the fraction of the parent samples used in the Tully-Fisher analysis, and how strictly the criterion of rotation dominated is enforced. Confining attention to subsamples of galaxies that are especially disky results in a consistent positive offset in Vc of ~ +0.1 dex, however these galaxies are not representative of the evolving-disk population at z > 1. We investigate the addition of pressure support, traced by intrinsic velocity dispersion ($sigma_{int}$) to the KDS dynamical mass budget by adopting a total effective velocity of form $V_{tot} = (Vc^{2} + 4.0sigma_{int}^{2})^{0.5}$. The rotation-dominated and dispersion-dominated KDS galaxies fall on the same locus in the total-velocity versus stellar-mass plane, removing the need for debate over the precise selection threshold for rotation-dominated galaxies. The comparison sample offsets are in the range +0.08 to +0.15 dex in total-velocity zero-point (-0.30 to -0.55 dex in stellar-mass zero-point) from the local Tully-Fisher relation at z > 1, consistent with steady evolution of the ratio of dynamical to stellar mass with cosmic time.
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