scholarly journals Evolution of the anti-truncated stellar profiles of S0 galaxies since z = 0.6 in the SHARDS survey

2018 ◽  
Vol 615 ◽  
pp. A26 ◽  
Author(s):  
Alejandro Borlaff ◽  
M. Carmen Eliche-Moral ◽  
John E. Beckman ◽  
Alexandre Vazdekis ◽  
Alejandro Lumbreras-Calle ◽  
...  

Context. Anti-truncated lenticular galaxies (Type-III S0s) present tight scaling relations between their surface brightness photometric and structural parameters. Although several evolutionary models have been proposed for the formation of these structures, the observations of Type-III S0 galaxies are usually limited to the local Universe. Aims. We aim to compare the properties of Type-III discs in a sample of S0 galaxies at 0.2 < z < 0.6 with those of the local Universe. In this paper, we study the evolution of the photometric and structural scaling relations measured in the rest-frame R-band with z and the possible differences between the rest-frame (B − R) colours of the inner and outer disc profiles. Methods. We make use of a sample of 14 Type-III E/S0–S0 galaxies at 0.2 < z < 0.6 from the GOODS-N field identified and characterised in a previous paper. We study whether or not the correlations found in local Type-III S0 galaxies were present ~6 Gyr ago. We analyse the distribution of the surface brightness characteristic parameters (Rbreak, μbreak, hi, ho, μ0,i and μ0,o) as a function of the stellar mass and look to see if there is a significant change with z. We also derive their rest-frame (B − R) colour profiles. Finally, we compare these results with the predictions from a grid of SSP models. Results. We find that the inner and outer scale-lengths of Type-III S0 galaxies at 0.4 < z < 0.6 follow compatible trends and scaling relations with those observed in local S0 galaxies as a function of the break radius, Rbreak. We do not detect any significant differences between the location of Rbreak between z ~ 0.6 and z ~ 0 for a fixed stellar mass of the object, whereas the surface brightness at the break radius μbreak is ~1.5 mag arcsec-2 dimmer in the local Universe than at z ~ 0.6 for a fixed stellar mass. We find no significant differences in the (B − R) colour between the inner and outer profiles of the Type-III S0 galaxies at 0.2 < z < 0.6. Conclusions. In contrast to Type-II (down-bending) profiles, the anti-truncated surface brightness profiles of S0 galaxies present compatible Rbreak values and scaling relations during the last 6 Gyr. This result and the similarity of the colours of the inner and outer discs point to a highly scalable and stable formation process, probably more related to gravitational and dynamical processes than to the evolution of stellar populations.

2016 ◽  
Vol 11 (S321) ◽  
pp. 280-280
Author(s):  
Alejandro Borlaff ◽  
M. Carmen Eliche-Moral ◽  
John Beckman ◽  
Pablo G. Pérez-González ◽  
Joan Font

AbstractLenticular galaxies (S0s) are more likely to host anti-truncated (Type III) stellar discs than galaxies of later Hubble types. Previous work on Type-III S0s at z = 0 revealed that the characteristic parameters of the breaks obey tight scaling relations (Borlaff et al. 2014). These relation are similar in both S0’s and spirals, in optical and NIR, and for barred and non-barred galaxies (Eliche-Moral et al. 2015). We have analysed 3DHST images (Brammer et al. 2012) of S0 galaxies from the SHARDS survey (Pérez-González et al. 2013) in order to investigate if E/S0 and S0 galaxies with anti-truncated stellar profiles up to z ~ 0.6 follow similar scaling relations compared to the local sample. We find that the characteristic photometric parameters of Type-III S0s at 0.4 < z < 0.6 obey analogous scaling relations to those observed in their local counterparts, lying on top of the extrapolations of the local trends towards brighter magnitudes in several photometric diagrams and sharing similar trends and values in the hi – RbrkIII, ho – RbrkIII and hi – ho diagrams. We have measured the offsets in magnitudes between two subsets of the z ~ 0.5 and z = 0 samples with similar masses (log 10M/M⊙ ~ 10.7). The median offsets are: ΔμbrkIII = − 2.23+0.46−0.62, Δμ0, i = − 2.61+0.31−0.26 and Δμ0, o = − 2.31+0.57−0.78 mag arcsec-2. We find that PSF corrections in our images do not significantly affect the scaling relations obtained in our 0.2 < z < 0.6 sample. In conclusion, the existence of similar scaling relations in Type-III S0 discs since z ~ 0.6 implies that the structures of the inner and outer discs in anti-truncated S0s have been similarly linked in the last ~ 6 Gyr, posing strong constraints to the processes proposed to explain their formation.


2012 ◽  
Vol 8 (S295) ◽  
pp. 230-230
Author(s):  
Elena Dalla Bontà ◽  
Roger L. Davies ◽  
Ryan C. W. Houghton ◽  
Francesco D'Eugenio ◽  
Enrico M. Corsini ◽  
...  

AbstractWe carried out a photometric analysis of a sample of early-type galaxies in Abell~1689 at z = 0.183, using HST/ACS archive images in the rest-frame V band. We performed a two-dimensional photometric decomposition of each galaxy surface-brightness distribution using the GASP2D fitting algorithm (Méndez-Abreu et al. 2008). We adopted both a Sérsic and de Vaucouleurs law. S0 galaxies were analysed also taking into account a disc component described by an exponential law. The derived photometric parameters, together with the ones previously obtained with the curve of growth method (Houghton et al. 2012), will be used to analyse the Fundamental Plane of Abell 1689 and quantify how it is affected by the use of different decomposition techniques (Dalla Bontà et al. 2013, in preparation). The stellar velocity dispersions of the sample galaxies were derived by using GEMINI-N/GMOS and VLT/FLAMES (D'Eugenio et al. 2013) spectroscopic data.


2020 ◽  
Vol 633 ◽  
pp. A100 ◽  
Author(s):  
V. Casasola ◽  
S. Bianchi ◽  
P. De Vis ◽  
L. Magrini ◽  
E. Corbelli ◽  
...  

Aims. The purpose of this work is the characterization of the main scaling relations between all of the interstellar medium (ISM) components, namely dust, atomic, molecular, and total gas, and gas-phase metallicity, as well as other galaxy properties, such as stellar mass (Mstar) and galaxy morphology, for late-type galaxies in the Local Universe. Methods. This study was performed by extracting late-type galaxies from the entire DustPedia sample and by exploiting the large and homogeneous dataset available thanks to the DustPedia project. The sample consists of 436 galaxies with morphological stage spanning from T = 1−10, Mstar from 6 × 107 to 3 × 1011 M⊙, star formation rate from 6 × 10−4 to 60 M⊙ yr−1, and oxygen abundance from 12 + log(O/H) = 8−9.5. Molecular and atomic gas data were collected from the literature and properly homogenized. All the masses involved in our analysis refer to the values within the optical disks of galaxies. The scaling relations involving the molecular gas are studied by assuming both a constant and a metallicity-dependent CO-to-H2 conversion factor (XCO). The analysis was performed by means of the survival analysis technique, in order to properly take into account the presence of both detection and nondetection in the data. Results. We confirm that the dust mass correlates very well with the total gas mass, and find –for the first time– that the dust mass correlates better with the atomic gas mass than with the molecular one. We characterize important mass ratios such as the gas fraction, the molecular-to-atomic gas mass ratio, the dust-to-total gas mass ratio (DGR), and the dust-to-stellar mass ratio, and study how they relate to each other, to galaxy morphology, and to gas-phase metallicity. Only the assumption of a metallicity-dependent XCO reproduces the expected decrease of the DGR with increasing morphological stage and decreasing gas-phase metallicity, with a slope of about 1. The DGR, the gas-phase metallicity, and the dust-to-stellar mass ratio are, for our galaxy sample, directly linked to galaxy morphology. The molecular-to-atomic gas mass ratio and the DGR show a positive correlation for low molecular gas fractions, but for galaxies rich in molecular gas this trend breaks down. To our knowledge, this trend has never been found before, and provides new constraints for theoretical models of galaxy evolution and a reference for high-redshift studies. We discuss several scenarios related to this finding. Conclusions. The DustPedia database of late-type galaxies is an extraordinary tool for the study of the ISM scaling relations, thanks to its homogeneous collection of data for the different ISM components. The database is made publicly available to the whole community.


2019 ◽  
Vol 15 (S341) ◽  
pp. 162-166
Author(s):  
K. Kouroumpatzakis ◽  
A. Zezas ◽  
P. H. Sell ◽  
P. Bonfini ◽  
M. L. N. Ashby ◽  
...  

AbstractIt is well known that X-ray luminosity (Lx) originating from high mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy’s star formation rate (SFR). We explore this connection using a sample representative of the star-formation activity in the local Universe (Star-Formation Reference Survey; SFRS) along with a comprehensive set of star-formation (radio, FIR, 24μm, 8 μm, Hα, UV, SED fitting) and stellar mass (K-band, 3.6 μm, SED fitting) indicators, and Chandra observations. We investigate the Lx–SFR and Lx– stellar mass (M*) scaling relations down to sub-galactic scales of ∼lkpc2. This way we extend these relations to extremely low SFR (∼10−6M⊙.yr−1) and M* (∼104M⊙). We also quantify their scatter and their dependence on the age of the local stellar populations as inferred from the different age sensitive SFR indicators. These results are particularly important for setting the benchmark for the formation of X-ray binaries in vigorous, but low SFR objects such as galaxies in the early Universe.


2021 ◽  
Vol 645 ◽  
pp. L13
Author(s):  
S. Comerón

One of the suggested thick disc formation mechanisms is that they were born quickly and in situ from a turbulent clumpy disc. Subsequently, thin discs formed slowly within them from leftovers of the turbulent phase and from material accreted through cold flows and minor mergers. In this Letter, I propose an observational test to verify this hypothesis. By combining thick disc and total stellar masses of edge-on galaxies with galaxy stellar mass functions calculated in the redshift range of z ≤ 3.0, I derived a positive correlation between the age of the youngest stars in thick discs and the stellar mass of the host galaxy; galaxies with a present-day stellar mass of ℳ⋆(z = 0) < 1010 ℳ⊙ have thick disc stars as young as 4 − 6 Gyr, whereas the youngest stars in the thick discs of Milky-Way-like galaxies are ∼10 Gyr old. I tested this prediction against the scarcely available thick disc age estimates, all of them are from galaxies with ℳ⋆(z = 0) ≳ 1010 ℳ⊙, and I find that field spiral galaxies seem to follow the expectation. On the other hand, my derivation predicts ages that are too low for the thick discs in lenticular galaxies, indicating a fast early evolution for S0 galaxies. I propose the idea of conclusively testing whether thick discs formed quickly and in situ by obtaining the ages of thick discs in field galaxies with masses of ℳ⋆(z = 0) ∼ 109.5 ℳ⊙ and by checking whether they contain ∼5 Gyr-old stars.


2019 ◽  
Vol 628 ◽  
pp. A4 ◽  
Author(s):  
M. A. Raj ◽  
E. Iodice ◽  
N. R. Napolitano ◽  
M. Spavone ◽  
H-S. Su ◽  
...  

Context. We present the study of a magnitude limited sample (mB ≤ 16.6 mag) of 13 late type galaxies (LTGs), observed inside the virial radius, Rvir ∼ 0.7 Mpc, of the Fornax cluster within the Fornax Deep Survey (FDS). Aims. The main objective is to use surface brightness profiles and g − i colour maps to obtain information on the internal structure of these galaxies and find signatures of the mechanisms that drive their evolution in high-density environments inside the virial radius of the cluster. Methods. By modelling galaxy isophotes, we extract the azimuthally averaged surface brightness profiles in four optical bands. We also derive g − i colour profiles, and relevant structural parameters like total magnitude and effective radius. For ten of the galaxies in this sample, we observe a clear discontinuity in their typical exponential surface brightness profiles, derive their “break radius”, and classify their disc-breaks into Type II (down-bending) or Type III (up-bending). Results. We find that Type II galaxies have bluer average (g − i) colour in their outer discs while Type III galaxies are redder. The break radius increases with stellar mass and molecular gas mass while it decreases with molecular gas-fractions. The inner and outer scale-lengths increase monotonically with absolute magnitude, as found in other works. For galaxies with CO(1-0) measurements, there is no detected cold gas beyond the break radius (within the uncertainties). In the context of morphological segregation of LTGs in clusters, we also find that, in Fornax, galaxies with morphological type 5 <  T ≤ 9 (∼60% of the sample) are located beyond the high-density, ETG-dominated regions, however there is no correlation between T and the disc-break type. We do not find any correlation between the average (g − i) colours and cluster-centric distance, but the colour-magnitude relation holds true. Conclusions. The main results of this work suggest that the disc-breaks of LTGs inside the virial radius of the Fornax cluster seem to have arisen through a variety of mechanisms (e.g. ram-pressure stripping, tidal disruption), which is evident in their outer-disc colours and the absence of molecular gas beyond their break radius in some cases. This can result in a variety of stellar populations inside and outside the break radii.


2011 ◽  
Vol 7 (S284) ◽  
pp. 166-169
Author(s):  
Sharon E. Meidt ◽  

AbstractWith deep imaging at 3.6 and 4.5 μm where the light in nearby galaxies is dominated by old stars, the Spitzer Survey of Stellar Structure in Nearby Galaxies (S4G) promises to be the ultimate inventory of stellar mass and structure in the local universe. We present results from a novel technique that makes it possible to fully exploit the information contained in these images, pertaining not only to the stellar light (and, ultimately, mass distribution), but also the nature and distribution of the mid-IR dust and the properties of evolved, intermediate age stars (e.g. in AGB-dominated star clusters). We apply Independent Component Analysis (ICA) to the 3.6 and 4.5 μm bands to separate the light from the old stars from the secondary non-stellar (i.e. PAH and hot dust) sources of emission, which are identified via comparison to the non-stellar emission imaged at 8 μm. Then, within the context of age and mass estimation at high z, we extract optical-to-mid-IR SEDs for a sample of ICA-identified AGB-dominated clusters to constrain the typically uncertain fractional contribution of AGB light to the total stellar emission in (rest-frame) NIR bands.


2020 ◽  
Vol 493 (3) ◽  
pp. 3580-3607
Author(s):  
Bogdan A Pastrav

ABSTRACT Accurate galaxy scaling relations are essential for a successful model of galaxy formation and evolution as they provide direct information about the physical mechanisms of galaxy assembly over cosmic time. We present here a detailed analysis of a sample of nearby spiral galaxies taken from the KINGFISH survey. The photometric parameters of the morphological components are obtained from bulge–disc decompositions using galfit data analysis algorithm, with surface photometry of the sample done beforehand. Dust opacities are determined using a previously discovered correlation between the central face-on dust opacity of the disc and the stellar mass surface density. The method and the library of numerical results previously obtained in Pastrav et al. (2013a,b) are used to correct the measured photometric and structural parameters for projection (inclination), dust, and decomposition effects in order to derive their intrinsic values. Galaxy disc scaling relations are then presented, both the measured (observed) and the intrinsic (corrected) ones, in the optical regime, to show the scale of the biases introduced by the aforementioned effects. The slopes of the size–luminosity relations and the dust versus stellar mass are in agreement with values found in other works. We derive mean dust optical depth and dust/stellar mass ratios of the sample, which we find to be consistent with previous studies of nearby spiral galaxies. While our sample is rather small, it is sufficient to quantify the influence of galaxy environment (dust, in this case) when deriving scaling relations.


2016 ◽  
Vol 11 (S321) ◽  
pp. 114-116
Author(s):  
Miguel Querejeta ◽  
M. Carmen Eliche-Moral ◽  
Trinidad Tapia ◽  
Alejandro Borlaff ◽  
Glenn van de Ven ◽  
...  

AbstractLenticular galaxies (S0s) represent the majority of early-type galaxies in the local Universe, but their formation channels are still poorly understood. While galaxy mergers are obvious pathways to suppress star formation and increase bulge sizes, the marked parallelism between spiral and lenticular galaxies (e.g. photometric bulge–disc coupling) seemed to rule out a potential merger origin. Here, we summarise our recent work in which we have shown, throughN-body numerical simulations, that disc-dominated lenticulars can emerge from major mergers of spiral galaxies, in good agreement with observational photometric scaling relations. Moreover, we show that mergers simultaneously increase the light concentration and reduce the angular momentum relative to their spiral progenitors. This explains the mismatch in angular momentum and concentration between spirals and lenticulars recently revealed by CALIFA observations, which is hard to reconcile with simple fading mechanisms (e.g. ram-pressure stripping).


2019 ◽  
Vol 15 (S359) ◽  
pp. 37-39
Author(s):  
Benjamin L. Davis ◽  
Nandini Sahu ◽  
Alister W. Graham

AbstractOur multi-component photometric decomposition of the largest galaxy sample to date with dynamically-measured black hole masses nearly doubles the number of such galaxies. We have discovered substantially modified scaling relations between the black hole mass and the host galaxy properties, including the spheroid (bulge) stellar mass, the total galaxy stellar mass, and the central stellar velocity dispersion. These refinements partly arose because we were able to explore the scaling relations for various sub-populations of galaxies built by different physical processes, as traced by the presence of a disk, early-type versus late-type galaxies, or a Sérsic versus core-Sérsic spheroid light profile. The new relations appear fundamentally linked with the evolutionary paths followed by galaxies, and they have ramifications for simulations and formation theories involving both quenching and accretion.


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