- ID:
- ivo://CDS.VizieR/J/A+A/640/A70
- Title:
- Massive discs in cosmological simulations
- Short Name:
- J/A+A/640/A70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the disc-halo connection in massive (M*>5x10^10^M_{sun}_) disc galaxies from the cosmological hydrodynamical simulations EAGLE and IllustrisTNG, and compare it with that inferred from the study of HI rotation curves in nearby massive spirals from the Spitzer Photometry and Accurate Rotation Curves (SPARC) dataset. We find that discrepancies between the simulated and observed discs arise both on global and on local scales. Globally, the simulated discs inhabit halos that are a factor 4 (in EAGLE) and 2 (in IllustrisTNG) more massive than those derived from the rotation curve analysis of the observed dataset. We also use synthetic rotation curves of the simulated discs to demonstrate that the recovery of the halo masses from rotation curves are not systematically biased. We find that the simulations predict dark-matter dominated systems with stellar-to-total enclosed mass ratios that are a factor of 1.5-2 smaller than real galaxies at all radii. This is an alternative manifestation of the `failed feedback problem', since it indicates that simulated halos hosting massive discs have been too inefficient at converting their baryons into stars, possibly due to an overly efficient stellar and/or AGN feedback implementation.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/428/1460
- Title:
- Massive early-type galaxies
- Short Name:
- J/MNRAS/428/1460
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Present-day massive galaxies are composed mostly of early-type objects. It is unknown whether this was also the case at higher redshifts. In a hierarchical assembling scenario the morphological content of the massive population is expected to change with time from disc-like objects in the early Universe to spheroid-like galaxies at present. In this paper we have probed this theoretical expectation by compiling a large sample of massive (M_stellar_>=10^11^h^-2^_70_M{sun}) galaxies in the redshift interval 0<z<3. Our sample of 1082 objects comprises 207 local galaxies selected from Sloan Digital Sky Survey plus 875 objects observed with the Hubble Space Telescope belonging to the Palomar Observatory Wide-field InfraRed/DEEP2 and GOODS NICMOS Survey surveys. 639 of our objects have spectroscopic redshifts. Our morphological classification is performed as close as possible to the optical rest frame according to the photometric bands available in our observations both quantitatively (using the Sersic index as a morphological proxy) and qualitatively (by visual inspection). Using both techniques we find an enormous change on the dominant morphological class with cosmic time. The fraction of early-type galaxies among the massive galaxy population has changed from ~20-30 per cent at z~3 to~70 per cent at z=0. Early-type galaxies have been the predominant morphological class for massive galaxies since only z~1.
- ID:
- ivo://CDS.VizieR/J/ApJ/762/83
- Title:
- Massive early-type galaxies in K-band
- Short Name:
- J/ApJ/762/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use high-resolution K-band VLT/HAWK-I imaging over 0.25deg^2^ to study the structural evolution of massive early-type galaxies since z~2. Mass-selected samples, complete down to log(M/M_{sun}_)~10.7 such that "typical" (L*) galaxies are included at all redshifts, are drawn from pre-existing photometric redshift surveys. We then separate the samples into different redshift slices and classify them as late- or early-type galaxies on the basis of their specific star formation rate. Axis-ratio measurements for the ~400 early-type galaxies in the redshift range 0.6<z<1.8 are accurate to 0.1 or better. The projected axis-ratio distributions are then compared with lower redshift samples. We find strong evidence for evolution of the population properties: early-type galaxies at z>1 are, on average, flatter than at z<1 and the median projected axis ratio at a fixed mass decreases with redshift. However, we also find that at all epochs z<~2, the most massive early-type galaxies (log(M/M_{sun}_)>11.3) are the roundest, with a pronounced lack of galaxies that are flat in projection. Merging is a plausible mechanism that can explain both results: at all epochs, merging is required for early-type galaxies to grow beyond log(M/M_{sun}_)~11.3, and all early types over time gradually and partially lose their disk-like characteristics.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/2687
- Title:
- Massive galaxies environmental density
- Short Name:
- J/MNRAS/471/2687
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using multiwavelength data, from ultraviolet to optical to near-infrared to mid-infrared, for ~6000 galaxies in the local Universe, we study the dependence of star formation on the morphological T-types for massive galaxies (logM*/M_{sun}_>=10). We find that, early-type spirals (Sa-Sbc) and S0s predominate in the green valley, which is a transition zone between the star forming and quenched regions. Within the early-type spirals, as we move from Sa to Sbc spirals the fraction of green valley and quenched galaxies decreases, indicating the important role of the bulge in the quenching of galaxies. The fraction of early-type spirals decreases as we enter the green valley from the blue cloud, which coincides with the increase in the fraction of S0s. These points towards the morphological transformation of early-type spiral galaxies into S0s, which can happen due to environmental effects such as ram-pressure stripping, galaxy harassment or tidal interactions. We also find a second population of S0s that are actively star forming and are present in all environments. Since morphological T-type, specific star formation rate (sSFR), and environmental density are all correlated with each other, we compute the partial correlation coefficient for each pair of parameters while keeping the third parameter as a control variable. We find that morphology most strongly correlates with sSFR, independent of the environment, while the other two correlations (morphology-density and sSFR-environment) are weaker. Thus, we conclude that, for massive galaxies in the local Universe, the physical processes that shape their morphology are also the ones that determine their star-forming state.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/1666
- Title:
- Massive galaxies in CANDELS-UDS field
- Short Name:
- J/MNRAS/427/1666
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used high-resolution, Hubble Space Telescope, near-infrared imaging to conduct a detailed analysis of the morphological properties of the most massive galaxies at high redshift, modelling the WFC3/IR H_160_-band images of the =~200 galaxies in the CANDELS-UDS field with photometric redshifts 1<z<3, and stellar masses M_*_>10^11^M_{sun}_. We have explored the results of fitting single-Sersic and bulge+disc models, and have investigated the additional errors and potential biases introduced by uncertainties in the background and the on-image point spread function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/382/109
- Title:
- Massive galaxies in Extended Groth Strip
- Short Name:
- J/MNRAS/382/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the combined capabilities of the large near-infrared Palomar/DEEP-2 survey, and the superb resolution of the Advanced Camera for Surveys HST camera, we explore the size evolution of 831 very massive galaxies (M*>=10^11^h^-2^_70_M_{sun}_) since z~2. We split our sample according to their light concentration using the Sersic index n. At a given stellar mass, both low (n<2.5) and high (n>2.5) concentrated objects were much smaller in the past than their local massive counterparts. This evolution is particularly strong for the highly concentrated (spheroid like) objects. At z~1.5, massive spheroid-like objects were a factor of 4(+/-0.4) smaller (i.e. almost two orders of magnitudes denser) than those we see today. These small sized, high-mass galaxies do not exist in the nearby Universe, suggesting that this population merged with other galaxies over several billion years to form the largest galaxies we see today.
- ID:
- ivo://CDS.VizieR/J/ApJ/695/259
- Title:
- Massive metal-poor galaxies from SDSS
- Short Name:
- J/ApJ/695/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 42 high-mass low-metallicity outliers from the mass-metallicity relation of star-forming galaxies. These galaxies have stellar masses that span log(M_*_/M_{sun}_)~9.4 to 11.1 and are offset from the mass-metallicity relation by -0.3 to -0.85dex in 12+log(O/H). In general, they are extremely blue, have high star-formation rates for their masses, and are morphologically disturbed. Tidal interactions are expected to induce large-scale gas inflow to the galaxies' central regions, and we find that these galaxies' gas-phase oxygen abundances are consistent with large quantities of low-metallicity gas from large galactocentric radii diluting the central metal-rich gas. We conclude with implications for deducing gas-phase metallicities of individual galaxies based solely on their luminosities, specifically in the case of long gamma-ray burst host galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/441/203
- Title:
- Massive quiescent ETG in clusters
- Short Name:
- J/MNRAS/441/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the mass-size relation of ~400 quiescent massive ETGs (M*/M_{sun}_>3x10^10^) hosted by massive clusters (M200~2-7x10^14^M_{sun}_) at 0.8<z<1.5, compared to those found in the field at the same epoch. Size is parametrized using the mass-normalized B-band rest-frame size, {gamma}=R_e_/M_11_^0.57^. We find that the {gamma} distributions in both environments peak at the same position, but the distributions in clusters are more skewed towards larger sizes. This tail induces average sizes ~ 30-40 percent larger for cluster galaxies than for field galaxies of similar stellar mass, while the median sizes are statistically the same with a difference of ~10+/-10%. Since this size difference is not observed in the local Universe, the evolution of average galaxy size at fixed stellar mass from z~1.5 for cluster galaxies is less steep at more than 3{sigma}({prop.to}(1+z)-0.53+/-0.04) than the evolution of field galaxies ({prop.to}(1+z)-0.92+/-0.04). The difference in evolution is not measured when the median values of {gamma} are considered: {prop.to}(1+z)-0.84+/-0.04 in the field versus {prop.to}(1+z)-0.71+/-0.05 in clusters. In our sample, the tail of large galaxies is dominated by galaxies with 3x10^10^<M*/M_{sun}_<10^11^. At this low-mass end, the difference in the average size is better explained by the accretion of new galaxies that are quenched more efficiently in clusters and/or by different morphological mixing in the cluster and field environments. If part of the size evolution would be due to mergers, the difference that we see between cluster and field galaxies could be caused by higher merger rates in clusters at higher redshift, when galaxy velocities are lower.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/3743
- Title:
- 104 massive quiescent galaxies SFHs
- Short Name:
- J/MNRAS/457/3743
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present star formation histories (SFHs) for a sample of 104 massive (stellar mass M>10^10^M_{sun}_) quiescent galaxies (MQGs) at z=1.0-1.5 from the analysis of spectrophotometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) and HST/WFC3 G102 and G141 surveys of the GOODS-North field, jointly with broad-band observations from ultraviolet (UV) to far-infrared (far-IR). The sample is constructed on the basis of rest-frame UVJ colours and specific star formation rates (sSFRs=SFR/Mass). The spectral energy distributions (SEDs) of each galaxy are compared to models assuming a delayed exponentially declining SFH. A Monte Carlo algorithm characterizes the degeneracies, which we are able to break taking advantage of the SHARDS data resolution, by measuring indices such as MgUV and D4000. The population of MQGs shows a duality in their properties. The sample is dominated (85 per cent) by galaxies with young mass-weighted ages, <t_M_><2Gyr, short star formation time-scales, <{tau}>~60-200MYr, and masses log(M/M_{sun}_)~10.5. There is an older population (15 per cent) with <t_M_>=2-4Gyr, longer star formation time-scales, <{tau}>~400Myr, and larger masses, log(M/M_{sun}_)~10.7. The SFHs of our MQGs are consistent with the slope and the location of the main sequence of star-forming galaxies at z>1.0, when our galaxies were 0.5-1.0Gyr old. According to these SFHs, all the MQGs experienced a luminous infrared galaxy phase that lasts for ~500Myr, and half of them an ultraluminous infrared galaxy phase for ~100Myr. We find that the MQG population is almost assembled at z~1, and continues evolving passively with few additions to the population.
- ID:
- ivo://CDS.VizieR/J/AJ/146/114
- Title:
- Massive stars in M101. I. HST BVI photometry
- Short Name:
- J/AJ/146/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An increasing number of non-terminal giant eruptions are being observed by modern supernova and transient surveys. But very little is known about the origin of these giant eruptions and their progenitors, many of which are presumably very massive, evolved stars. Motivated by the small number of progenitors positively associated with these giant eruptions, we have begun a survey of the evolved massive star populations in nearby galaxies. The nearby, nearly face-on, giant spiral M101 is an excellent laboratory for studying a large population of very massive stars. In this paper, we present BVI photometry obtained from archival HST/ACS Wide Field Camera images of M101. We have produced a catalog of luminous stars with photometric errors <10% for V<24.5 and 50% completeness down to V~26.5 even in regions of high stellar crowding. Using color and luminosity criteria, we have identified candidate luminous OB-type stars and blue supergiants, yellow supergiants, and red supergiants for future observation. We examine their spatial distributions across the face of M101 and find that the ratio of blue to red supergiants decreases by two orders of magnitude over the radial extent of M101 corresponding to 0.5 dex in metallicity. We discuss the resolved stellar content in the giant star-forming complexes NGC 5458, 5453, 5461, 5451, 5462, and 5449 and discuss their color-magnitude diagrams in conjunction with the spatial distribution of the stars to determine their spatio-temporal formation histories.
