scholarly journals Kinematic Evolution of Field and Cluster Spiral Galaxies

2014 ◽  
Vol 10 (S311) ◽  
pp. 146-149
Author(s):  
Bodo L. Ziegler ◽  
Asmus Böhm
Keyword(s):  
Star Formation ◽  
Linear Trend ◽  
Stellar Structure ◽  
Star Formation History ◽  
Stellar Disk ◽  
Chemical Enrichment ◽  
Kinematic Evolution ◽  
Disk Structure ◽  
Significant Difference ◽  
Stellar Masses

AbstractWe investigate the evolution of the Tully–Fisher relation out to z = 1 with 137 emission-line galaxies in the field that display a regular rotation curve. They follow a linear trend with lookback time being on average brighter by 1.1 Bmag and 60% smaller at z = 1. For a subsample of 48 objects with very regular gas kinematics and stellar structure we derive a TF scatter of 1.15mag, which is two times larger than local samples exhibit. This is probably due to modest variations in their star formation history and chemical enrichment.In another study of 96 members of Abell 901/902 at z = 0.17 and 86 field galaxies with similar redshifts we find a difference in the TFR of 0.42mag in the B-band but no significant difference in stellar mass. Comparing specifically red spirals with blue ones in the cluster, the former are fainter on average by 0.35 Bmag and have 15% lower stellar masses. This is probably due to star formation quenching caused by ram-pressure in the cluster environment. Evidence for this scenario comes from strong distortions of the gas disk of red spirals that have at the same time a very regular stellar disk structure.

scholarly journals Star Formation History of Early-Type Galaxies with Tidal Debris in the S4G

2012 ◽  
Vol 10 (H16) ◽  
pp. 129-129
Author(s):  
Beatriz H. F. Ramos ◽  
Karín Menéndez-Delmestre ◽  
Taehyun Kim ◽  
Kartik Sheth ◽  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Stellar Structure ◽  
Star Formation History ◽  
Early Type ◽  
Uv Emission ◽  
Optical Images ◽  
Formation History ◽  
History Of ◽  
Stellar Masses

AbstractLocal early-type galaxies (ETGs), despite typically being associated to old stellar populations and passive evolution, have been in some cases observed to present peculiarities in their stellar structure, like disks and shells (e.g., Kormendy et al.1997, Rix, Carollo & Freeman 1999). Moreover, it has been observed that ETGs with such tidal features may present UV emission (Rampazzo et al.2007, Salim & Rich 2010). These properties make them relevant constraints to galaxy formation models. We are analysing the structure of nearby ETGs observed in the Spitzer Survey of Stellar Structure in Galaxies (S4G; Sheth et al.2010), which comprises the largest mid-IR survey of galaxies in the local Universe. We perform a 2D GALFIT decomposition of the 3.6μm images of 146 ETGs and examine their residual images. We identify tidal features in 17% of these, suggesting that a non-negligible ETGs fraction may have experienced (after the formation of the bulk of their stellar budget) merger events that have left signatures (Canalizo et al.2007). For 6 of these peculiar ETGs, we also applied GALFIT decomposition to public GALEX/UV and SDSS/optical images. With measurements in multiple bands, we applied SED fitting techniques to estimate star formation rates (SFR) and stellar masses for the galaxies and their tidal features. We find that these 6 peculiar ETGs present masses in agreement with the population of non-peculiar ETGs. However, SFRs are higher than what has been measured for the average ETG population (Shapiro et al.2010, SDSS MPA-JHU catalog). Based on the Kaviraj (2010) relation, we find that for these peculiar ETGs the estimated age of the most recent star formation event is less than 3Gyrs. Despite this indication of recent star formation, we have not found evidence of prominent UV emission in the tidal features (Marino et al.2010). We are currently extending our work to the full sample of peculiar ETGs identified in our sample.

scholarly journals How robustly can we constrain the low-mass end of the z ∼ 6−7 stellar mass function? The limits of lensing models and stellar population assumptions in the Hubble Frontier Fields

2020 ◽  
Vol 501 (2) ◽  
pp. 1568-1590
Author(s):  
Lukas J Furtak ◽  
Hakim Atek ◽  
Matthew D Lehnert ◽  
Jacopo Chevallard ◽  
Stéphane Charlot
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Stellar Mass ◽  
Star Formation History ◽  
Space Telescope ◽  
Formation History ◽  
Low Mass ◽  
Stellar Masses ◽  
Dust Attenuation ◽  
The Impact

ABSTRACT We present new measurements of the very low mass end of the galaxy stellar mass function (GSMF) at z ∼ 6−7 computed from a rest-frame ultraviolet selected sample of dropout galaxies. These galaxies lie behind the six Hubble Frontier Field clusters and are all gravitationally magnified. Using deep Spitzer/IRAC and Hubble Space Telescope imaging, we derive stellar masses by fitting galaxy spectral energy distributions and explore the impact of different model assumptions and parameter degeneracies on the resulting GSMF. Our sample probes stellar masses down to $M_{\star }\gt 10^{6}\, \text{M}_{\odot}$ and we find the z ∼ 6−7 GSMF to be best parametrized by a modified Schechter function that allows for a turnover at very low masses. Using a Monte Carlo Markov chain analysis of the GSMF, including accurate treatment of lensing uncertainties, we obtain a relatively steep low-mass end slope $\alpha \simeq -1.96_{-0.08}^{+0.09}$ and a turnover at $\log (M_T/\text{M}_{\odot})\simeq 7.10_{-0.56}^{+0.17}$ with a curvature of $\beta \simeq 1.00_{-0.73}^{+0.87}$ for our minimum assumption model with constant star formation history (SFH) and low dust attenuation, AV ≤ 0.2. We find that the z ∼ 6−7 GSMF, in particular its very low mass end, is significantly affected by the assumed functional form of the star formation history and the degeneracy between stellar mass and dust attenuation. For example, the low-mass end slope ranges from $\alpha \simeq -1.82_{-0.07}^{+0.08}$ for an exponentially rising SFH to $\alpha \simeq -2.34_{-0.10}^{+0.11}$ when allowing AV of up to 3.25. Future observations at longer wavelengths and higher angular resolution with the James Webb Space Telescope are required to break these degeneracies and to robustly constrain the stellar mass of galaxies on the extreme low-mass end of the GSMF.

scholarly journals Horizon-AGN virtual observatory – 1. SED-fitting performance and forecasts for future imaging surveys

2019 ◽  
Vol 486 (4) ◽  
pp. 5104-5123 ◽  
Author(s):  
C Laigle ◽  
I Davidzon ◽  
O Ilbert ◽  
J Devriendt ◽  
D Kashino ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Star Formation History ◽  
Photometric Redshifts ◽  
Dark Energy Survey ◽  
Hydrodynamical Simulation ◽  
Formation History ◽  
Stellar Masses ◽  
Dust Attenuation ◽  
The Impact

Abstract Using the light-cone from the cosmological hydrodynamical simulation horizon-AGN, we produced a photometric catalogue over 0 < z < 4 with apparent magnitudes in COSMOS, Dark Energy Survey, Large Synoptic Survey Telescope (LSST)-like, and Euclid-like filters at depths comparable to these surveys. The virtual photometry accounts for the complex star formation history (SFH) and metal enrichment of horizon-AGN galaxies, and consistently includes magnitude errors, dust attenuation, and absorption by intergalactic medium. The COSMOS-like photometry is fitted in the same configuration as the COSMOS2015 catalogue. We then quantify random and systematic errors of photometric redshifts, stellar masses, and star formation rates (SFR). Photometric redshifts and redshift errors capture the same dependencies on magnitude and redshift as found in COSMOS2015, excluding the impact of source extraction. COSMOS-like stellar masses are well recovered with a dispersion typically lower than 0.1 dex. The simple SFHs and metallicities of the templates induce a systematic underestimation of stellar masses at z < 1.5 by at most 0.12 dex. SFR estimates exhibit a dust-induced bimodality combined with a larger scatter (typically between 0.2 and 0.6 dex). We also use our mock catalogue to predict photometric redshifts and stellar masses in future imaging surveys. We stress that adding Euclid near-infrared photometry to the LSST-like baseline improves redshift accuracy especially at the faint end and decreases the outlier fraction by a factor ∼2. It also considerably improves stellar masses, reducing the scatter up to a factor 3. It would therefore be mutually beneficial for LSST and Euclid to work in synergy.

scholarly journals The star formation history of galaxies in 3D: CALIFA perspective

2014 ◽  
Vol 10 (S309) ◽  
pp. 99-104
Author(s):  
R. M. González Delgado ◽  
R. Cid Fernandes ◽  
R. García-Benito ◽  
E. Pérez ◽  
A. L. de Amorim ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Density ◽  
Spectral Synthesis ◽  
Stellar Mass ◽  
Star Formation History ◽  
Chemical Enrichment ◽  
Radial Profiles ◽  
Formation History ◽  
The Galaxy ◽  
History Of

AbstractWe resolve spatially the star formation history of 300 nearby galaxies from the CALIFA integral field survey to investigate: a) the radial structure and gradients of the present stellar populations properties as a function of the Hubble type; and b) the role that plays the galaxy stellar mass and stellar mass surface density in governing the star formation history and metallicity enrichment of spheroids and the disks of galaxies. We apply the fossil record method based on spectral synthesis techniques to recover spatially and temporally resolved maps of stellar population properties of spheroids and spirals with galaxy mass from 109 to 7×1011 M⊙. The individual radial profiles of the stellar mass surface density (μ⋆), stellar extinction (AV), luminosity weighted ages (〈logage〉L), and mass weighted metallicity (〈log Z/Z⊙〉M) are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc and Sd). All these properties show negative gradients as a sight of the inside-out growth of massive galaxies. However, the gradients depend on the Hubble type in different ways. For the same galaxy mass, E and S0 galaxies show the largest inner gradients in μ⋆; and Andromeda-like galaxies (Sb with log M⋆ (M⊙) ∼ 11) show the largest inner age and metallicity gradients. In average, spiral galaxies have a stellar metallicity gradient ∼ −0.1 dex per half-light radius, in agreement with the value estimated for the ionized gas oxygen abundance gradient by CALIFA. A global (M⋆-driven) and local (μ⋆-driven) stellar metallicity relation are derived. We find that in disks, the stellar mass surface density regulates the stellar metallicity; in spheroids, the galaxy stellar mass dominates the physics of star formation and chemical enrichment.

scholarly journals Modelling Stellar Populations at High Redshift

2010 ◽  
Vol 6 (S277) ◽  
pp. 158-165
Author(s):  
Claudia Maraston
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Stellar Populations ◽  
Star Formation History ◽  
Population Modelling ◽  
Massive Galaxies ◽  
Star Forming ◽  
Formation History ◽  
Derived Properties ◽  
Stellar Masses

AbstractStellar populations carry information about the formation of galaxies and their evolution up to the present epoch. A wealth of observational data are available nowadays, which are analysed with stellar population models in order to obtain key properties such as ages, star formation histories, stellar masses. Differences in the models and/or in the assumptions regarding the star formation history affect the derived properties as much as differences in the data. I shall review the interpretation of high-redshift galaxy data from a model perspective. While data quality dominates galaxy analysis at the highest possible redshifts (z > 5), population modelling effects play the major part at lower redshifts. In particular, I discuss the cases of both star-forming galaxies at the peak of the cosmic star formation history as well as passive galaxies at redshift below 1 that are often used as cosmological probes. Remarks on the bridge between low and high-z massive galaxies conclude the contribution.

scholarly journals The properties of He IIλ1640 emitters at z ∼  2.5–5 from the VANDELS survey

2020 ◽  
Vol 636 ◽  
pp. A47 ◽  
Author(s):  
A. Saxena ◽  
L. Pentericci ◽  
M. Mirabelli ◽  
D. Schaerer ◽  
R. Schneider ◽  
...  
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Stellar Population ◽  
Stellar Ages ◽  
Significant Difference ◽  
Consistent Manner ◽  
Multi Wavelength ◽  
Low Metallicity ◽  
Stellar Masses ◽  
X Ray Binaries

Aims. Strong He II emission is produced by low-metallicity stellar populations. Here, we aim to identify and study a sample of He IIλ1640-emitting galaxies at redshifts of z ∼ 2.5 − 5 in the deep VANDELS spectroscopic survey. Methods. We identified a total of 33 Bright He II emitters (S/N >  2.5) and 17 Faint emitters (S/N <  2.5) in the VANDELS survey and used the available deep multi-wavelength data to study their physical properties. After identifying seven potential AGNs in our sample and discarding them from further analysis, we divided the sample of Bright emitters into 20 Narrow (FWHM <  1000 km s−1) and 6 Broad (FWHM >  1000 km s−1) He II emitters. We created stacks of Faint, Narrow, and Broad emitters and measured other rest-frame UV lines such as O III] and C III] in both individual galaxies and stacks. We then compared the UV line ratios with the output of stellar population-synthesis models to study the ionising properties of He II emitters. Results. We do not see a significant difference between the stellar masses, star-formation rates, and rest-frame UV magnitudes of galaxies with He II and no He II emission. The stellar population models reproduce the observed UV line ratios from metals in a consistent manner, however they under-predict the total number of He II ionising photons, confirming earlier studies and suggesting that additional mechanisms capable of producing He II are needed, such as X-ray binaries or stripped stars. The models favour subsolar metallicities (∼0.1 Z⊙) and young stellar ages (106 − 107 years) for the He II emitters. However, the metallicity measured for He II emitters is comparable to that of non-He II emitters at similar redshifts. We argue that galaxies with He II emission may have undergone a recent star-formation event, or may be powered by additional sources of He II ionisation.

scholarly journals Old main-sequence turnoff photometry in the SMC: Star Formation History and Chemical Enrichment Law

2006 ◽  
Vol 2 (S241) ◽  
Author(s):  
Noelia E. D. Noël ◽  
Carme Gallart ◽  
Antonio Aparicio ◽  
Sebastián L. Hidalgo ◽  
Ricardo Carrera ◽  
...  
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Star Formation History ◽  
Chemical Enrichment ◽  
Formation History

scholarly journals Galaxies in the first billion years: implications for re-ionization and the star formation history at z>6

2006 ◽  
Vol 2 (14) ◽  
pp. 248-248
Author(s):  
Andrew J. Bunker ◽  
Elizabeth R. Stanway ◽  
Laurence P. Eyles ◽  
Richard S. Ellis ◽  
Richard G. McMahon ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Populations ◽  
Star Formation History ◽  
Star Forming ◽  
Formation History ◽  
Stellar Masses ◽  
The Universe ◽  
Selection Of

AbstractWe discuss the selection of star-forming galaxies at z≃6 through the Lyman-break technique. Spitzer imaging implies many of these contain older stellar populations (>200Myr) which produce detectable Balmer breaks. The ages and stellar masses (∼1010M⊙) imply that the star formation rate density at earlier epochs may have been significantly higher than at z≃6, and might have played a key role in re-ionizing the universe.

scholarly journals Multi-Color Surface Photometry of Nearby Galaxies

1998 ◽  
Vol 179 ◽  
pp. 285-286
Author(s):  
T. Ichikawa ◽  
N. Itoh ◽  
K. Yanagisawa
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Spiral Galaxies ◽  
Stellar Structure ◽  
Star Formation History ◽  
Optical Observations ◽  
Wide Field ◽  
Formation History

Near-infrared (NIR) emission in galaxies is mainly radiated by old population low temperature stars, which construct the basic stellar structure and keep the trails of past galaxy evolution. On the other hand, optical observations show recent star formation activity, especially in spiral galaxies. Therefore multi-color observations from optical to near-infrared wavelengths are very important to understand the past and recent star-formation history. Nearby large galaxies are well studied not only in optical but also in mid- and far-infrared by IRAS, CO and HI radio observations. However, the study in the near-infrared is still limited because large format arrays are not common. Here we show a wide-field, near-infrared imaging of nearby elliptical and spiral galaxies and discuss their star-formation history.

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