- ID:
- ivo://CDS.VizieR/J/A+A/592/A64
- Title:
- Disk galaxies at 0.1<z<1.0
- Short Name:
- J/A+A/592/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy scaling relations such as the Tully-Fisher relation (between the maximum rotation velocity Vmax and luminosity) and the velocity-size relation (between Vmax and the disk scale length) are powerful tools to quantify the evolution of disk galaxies with cosmic time. We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z~1 using the FORS instruments of the ESO Very Large Telescope. The targets were selected from the FORS Deep Field and William Herschel Deep Field. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the two-dimensional spectra. Taking into account all geometrical, observational, and instrumental effects, these rotation curves were used to derive the intrinsic V_max. Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax was reliably determined for 124 galaxies covering redshifts 0.05<z<0.97. This is one of the largest kinematic samples of distant disk galaxies to date. We compared this data set to the local B-band Tully-Fisher relation and the local velocity-size relation. The scatter in both scaling relations is a factor of ~2 larger at z~0.5 than at z~0. The deviations of individual distant galaxies from the local Tully-Fisher relation are systematic in the sense that the galaxies are increasingly overluminous toward higher redshifts, corresponding to an overluminosity {Delta}M_B_=-(1.2+/-0.5) mag at z=1. This luminosity evolution at given Vmax is probably driven by younger stellar populations of distant galaxies with respect to their local counterparts, potentially combined with modest changes in dark matter mass fractions. The analysis of the velocity-size relation reveals that disk galaxies of a given Vmax have grown in size by a factor of ~1.5 over the past ~8Gyr, most likely through accretion of cold gas and/or small satellites. From scrutinizing the combined evolution in luminosity and size, we find that the galaxies that show the strongest evolution toward smaller sizes at z~1 are not those that feature the strongest evolution in luminosity, and vice versa.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/586/A96
- Title:
- Disk-locking PMS evolutionary tracks
- Short Name:
- J/A+A/586/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotational evolution in young stars is described by pre-main sequence evolutionary tracks including non-gray boundary conditions, rotation, conservation of angular momentum, and simulations of disk-locking. By assuming that disk-locking is the regulation mechanism for the stellar angular velocity during the early stages of pre-main sequence evolution, we use our rotating models and observational data to constrain disk lifetimes (Tdisk) of a representative sample of low-mass stars in two young clusters, the Orion Nebula cluster (ONC) and NGC 2264, and to better understand their rotational evolution. The period distributions of the ONC and NGC 2264 are known to be bimodal and to depend on the stellar mass. To follow the rotational evolution of these two clusters' stars, we generated sets of evolutionary tracks from a fully convective configuration with low central temperatures (before D- and Li-burning). We assumed that the evolution of fast rotators can be represented by models considering conservation of angular momentum during all stages and of moderate rotators by models considering conservation of angular velocity during the first stages of evolution. With these models we estimate a mass and an age for all stars.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A85
- Title:
- Disk masses in the Orion Molecular Cloud-2
- Short Name:
- J/A+A/628/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass evolution of protoplanetary disks is driven by internal processes and by external factors such as photoevaporation. Disentangling these two effects, however, remains difficult. We measured the dust masses of a sample of 132 disks in the Orion Molecular Cloud 2 (OMC-2) region, and compared them to externally photoevaporated disks in the Trapezium cluster, and to disks in nearby low-mass star-forming regions (SFRs). This allowed us to test whether initial disk properties are the same in high- and low-mass SFRs, and enabled a direct measurement of the effect of external photoevaporation on disks. A ~20'x4'mosaic of 3mm continuum observations from the Atacama Large Millimeter/submillimeter Array (ALMA) was used to measure the fluxes of 132 disks and 35 protostars >0.5pc away from the Trapezium. We identify and characterize a sample of 34 point sources not included in the Spitzer catalog on which the sample is based. Of the disks, 37 (28%) are detected, and have masses ranging from 7-270M_{sun}_. The detection rate for protostars is higher (69%). Disks near the Trapezium are found to be less massive by a factor 0.18^+0.18^_-0.11), implying a mass loss rate of 8x10^-8^M_{sun}_/yr. Our observations allow us to distinguish the impact of time and environment on disk evolution in a single SFR. The disk mass distribution in OMC-2 is statistically indistinguishable from that in nearby low-mass SFRs like Lupus and Taurus. We conclude that age is the main factor that determines the evolution of these disks. This result is robust with respect to assumptions of dust temperature, sample incompleteness, and biases. The difference between the OMC-2 and Trapezium cluster samples is consistent with mass loss driven by far-ultraviolet radiation near the Trapezium. Taken together, this implies that in isolation disk formation and evolution proceed similarly, regardless of cloud mass.
- ID:
- ivo://CDS.VizieR/J/ApJ/642/1140
- Title:
- Disk mass loss in the Orion Nebula Cluster
- Short Name:
- J/ApJ/642/1140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relevance of encounters on the destruction of protoplanetary disks in the Orion Nebula cluster (ONC) is investigated by combining two different types of numerical simulation. First, star-cluster simulations are performed to model the stellar dynamics of the ONC, the results of which are used to investigate the frequency of encounters, the mass ratio and separation of the stars involved, and the eccentricity of the encounter orbits.
4515. Disk of {upsilon} Sgr
- ID:
- ivo://CDS.VizieR/J/A+A/499/827
- Title:
- Disk of {upsilon} Sgr
- Short Name:
- J/A+A/499/827
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this paper is to determine the properties of the dusty environment of the hydrogen-deficient binary system upsilon Sgr, whose binary properties and other characteristics are poorly known. We obtained the first mid-IR interferometric observations of upsilon Sgr using the instrument MIDI of the VLTI used with different pairs of 1.8m and 8m telescopes. The calibrated visibilities, the N band spectrum, and the SED were compared with disk models computed with the MC3D code to determine the geometry and chemical composition of the envelope. ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
- ID:
- ivo://CDS.VizieR/J/AJ/159/74
- Title:
- Disk-resolved photometric properties of Pluto
- Short Name:
- J/AJ/159/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A multiwavelength regionally dependent photometric analysis of Pluto's anti-Charon-facing hemisphere using images collected by New Horizons' Multispectral Visible Imaging Camera (MVIC) reveals large variations in the absolute value and spectral slope of the single-scattering albedo. Four regions of interest are analyzed: the dark equatorial belt, Pluto's north pole, nitrogen-rich regions, and the mid-latitude terrains. Regions dominated by volatile ices such as Lowell Regio and Sputnik Planitia present single-scattering albedos of ~0.98 at 492nm, almost neutral across MVIC's visible wavelength range (400-910nm), indicating limited contributions from tholin materials. Pluto's dark equatorial regions, informally named Cthulhu and Krun Maculae, have single-scattering albedos of ~0.16 at 492nm and are the reddest regions. Applying the Hapke radiative transfer model to combined MVIC and Linear Etalon Imaging Spectral Array (LEISA) spectra (400-2500nm) of Cthulhu Macula and Lowell Regio successfully reproduces the spectral properties of these two regions of dramatically disparate coloration, composition, and morphology. Since this model uses only a single coloring agent, very similar to the Titan like tholin of Khare+ (1984Icar...60..127K), to account for all of Pluto's colors, this result supports the Grundy+ (2016Sci...351.9189G) conclusion that Pluto's coloration is the result of photochemical products mostly produced in the atmosphere. Although cosmic rays and extreme ultraviolet photons reach Pluto's surface where they can drive chemical processing, observations of diverse surface colors do not require different chemical products produced in different environments. We report a correction scaling factor in the LEISA radiometric calibration of 0.74{+/-}0.05.
- ID:
- ivo://CDS.VizieR/J/ApJ/688/362
- Title:
- Disks around brown dwarfs in {sigma} Ori cluster
- Short Name:
- J/ApJ/688/362
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a census of circumstellar disks around brown dwarfs in the {sigma} Ori cluster using all available images from the Infrared Array Camera on board the Spitzer Space Telescope. To search for new low-mass cluster members with disks, we have measured photometry for all sources in the Spitzer images and have identified the ones that have red colors that are indicative of disks. We present five promising candidates, which may consist of two brown dwarfs, two stars with edge-on disks, and a low-mass protostar if they are bona fide members. Spectroscopy is needed to verify the nature of these sources. We have also used the Spitzer data to determine which of the previously known probable members of {sigma} Ori are likely to have disks. By doing so, we measure disk fractions of ~40% and ~60% for low-mass stars and brown dwarfs, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A108
- Title:
- Disks around post-AGB binaries fit results
- Short Name:
- J/A+A/631/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Post-asymptotic giant branch (pAGB) binaries are surrounded by circumbinary disks of gas and dust that are similar to protoplanetary disks found around young stars. We aim to understand the structure of these disks and identify the physical phenomena at play in their very inner regions. We want to understand the disk-binary interaction and to further investigate the comparison with protoplanetary disks. We conducted an interferometric snapshot survey of 23 post-AGB binaries in the near-infrared (H-band) using VLTI/PIONIER. We fit the multi-wavelength visibilities and closure phases with purely geometrical models with an increasing complexity (including two point-sources, an azimuthally modulated ring, and an over-resolved flux) in order to retrieve the sizes, temperatures, and flux ratios of the different components. All sources are resolved and the different components contributing to the H-band flux are dissected. The environment of these targets is very complex: 13/23 targets need models with thirteen or more parameters to fit the data. We find that the inner disk rims follow and extend the size-luminosity relation established for disks around young stars with an offset toward larger sizes. The measured temperature of the near-infrared circumstellar emission of post-AGB binaries is lower (Tsub~1200K) than for young stars, which is probably due to a different dust mineralogy and/or gas density in the dust sublimation region. The dusty inner rims of the circumbinary disks around post-AGB binaries are ruled by dust sublimation physics. Additionally a significant amount of the circumstellar $H$-band flux is over-resolved (more than 10% of the non-stellar flux is over-resolved in 14 targets). This hints that a source of unknown origin, either a disk structure or outflow. The amount of over-resolved flux is larger than around young stars. Due to the complexity of these targets, interferometric imaging is a necessary tool to reveal the interacting inner regions in a model-independent way.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A82
- Title:
- Disks around T Tauri stars with SPHERE. II.
- Short Name:
- J/A+A/633/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-IR polarimetric images of protoplanetary disks provide the ability to characterize sub-structures that are potentially due to the interaction with (forming) planets. The available census is, however, strongly biased toward massive disks around old stars. The DARTTS program aims at alleviating this bias by imaging a large number of T Tauri stars with diverse properties. DARTTS-S employs VLT/SPHERE to image the polarized scattered light from disks. In parallel, DARTTS-A is providing ALMA images of the same targets for a comparison of different dust components. In this work, we present new SPHERE images of 21 circumstellar disks, which is the largest sample of this time yet to be released. A re-calculation of some relevant stellar and disk properties following Gaia DR2 is also performed. The targets of this work are significantly younger than those published thus far with polarimetric NIR imaging. Scattered light is unambiguously resolved in 11 targets while some polarized unresolved signal is detected in 3 additional sources. Some disk sub-structures are detected. However, the paucity of spirals and shadows from this sample reinforces the trend for which these NIR features are associated with Herbig stars, either because older or more massive. Furthermore, disk rings that are apparent in ALMA observations of some targets do not appear to have corresponding detections with SPHERE. Inner cavities larger than 15au are also absent from our images despite being expected from the SED. On the other hand, 3 objects show extended filaments at larger scale that are indicative of strong interaction with the surrounding medium. All but one of the undetected disks are best explained by their limited size (<~20au) and the high occurrence of stellar companions in these sources suggest an important role in limiting the disk size. One undetected disk is massive and very large at millimeter wavelengths implying it is self-shadowed in the near-IR. This work paves the way towards a more complete and less biased sample of scattered-light observations, which is required to interpret how disk features evolve throughout the disk lifetime.
4520. Dislodged AGNs
- ID:
- ivo://CDS.VizieR/J/ApJ/835/L30
- Title:
- Dislodged AGNs
- Short Name:
- J/ApJ/835/L30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate a sample of 2293 ICRF2 extragalactic radio-loud sources with accurate positions determined by VLBI, mostly active galactic nuclei (AGNs) and quasars, which are cross-matched with optical sources in the first Gaia release (Gaia DR1). The distribution of offsets between the VLBI sources and their optical counterparts is strongly non-Gaussian, with powerful wings extending beyond 1 arcsec. Limiting our analysis to only high-confidence difference detections, we find (and publish) a list of 188 objects with normalized variances above 12 and offsets below 1 arcsec. Pan-STARRS stacked and monochromatic images resolve some of these sources, indicating the presence of double sources, confusion sources, or pronounced extended structures. Some 89 high-quality objects, however, do not show any perturbations and appear to be star-like single sources, yet they are displaced by multiples of the expected error from the radio-loud AGN. We conclude that a fraction of luminous AGNs (more than 4%) can be physically dislodged from the optical centers of their parent galaxies.