- ID:
- ivo://CDS.VizieR/J/MNRAS/433/2986
- Title:
- SDSSRC3 sample morphological classifications
- Short Name:
- J/MNRAS/433/2986
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxies grow primarily via accretion-driven star formation in discs and merger-driven growth of bulges. These processes are implicit in semi-analytical models of galaxy formation, with bulge growth in particular relating directly to the hierarchical build-up of haloes and their galaxies. In this paper, we consider several implementations of two semi-analytical models. Focusing on implementations in which bulges are formed during mergers only, we examine the fractions of elliptical galaxies and both passive and star-forming disc galaxies as functions of stellar and halo mass, for central and satellite systems. This is compared to an observational cross-matched Sloan Digital Sky Survey+Third Reference Catalog of Bright Galaxies z~0 sample of galaxies with accurate visual morphological classifications and M*>10^10.5^M_{sun}_. The models qualitatively reproduce the observed increase of elliptical fraction with stellar mass, and with halo mass for central galaxies, supporting the idea that observed ellipticals form during major mergers. However, the overall elliptical fraction produced by the models is much too high compared with the z~0 data. Since the 'passive' - i.e. non-star-forming - fractions are approximately reproduced, and since the fraction which are star-forming disc galaxies is also reproduced, the problem is that the models overproduce ellipticals at the expense of passive S0 and spiral galaxies. Bulge growth implementations (tuned to reproduce simulations) which allow the survival of residual discs in major mergers still destroy too much of the disc. Increasing the lifetime of satellites, or allowing significant disc regrowth around merger remnants, merely increases the fraction of star-forming disc galaxies. Instead, it seems necessary to reduce the mass ratios of merging galaxies, so that most mergers produce modest bulge growth in disc galaxy remnants instead of ellipticals. This could be a natural consequence of tidal stripping of stars from infalling satellite galaxies, a process not considered in our models. However, a high efficiency of quenching during and/or subsequent to minor mergers is still required to keep the passive fraction high.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/412/727
- Title:
- SDSS red gal. automated morph. classification
- Short Name:
- J/MNRAS/412/727
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the last decade, the advent of enormous galaxy surveys has motivated the development of automated morphological classification schemes to deal with large data volumes. Existing automated schemes can successfully distinguish between early- and late-type galaxies and identify merger candidates, but are inadequate for studying detailed morphologies of red sequence galaxies. To fill this need, we present a new automated classification scheme that focuses on making finer distinctions between early types roughly corresponding to Hubble types E, S0 and Sa. We visually classify a sample of 984 non-star-forming Sloan Digital Sky Survey galaxies with apparent sizes >14-arcsec. We then develop an automated method to closely reproduce the visual classifications, which both provides a check on the visual results and makes it possible to extend morphological analysis to much larger samples. We visually classify the galaxies into three bulge classes (BC) by the shape of the light profile in the outer regions: discs have sharp edges and bulges do not, while some galaxies are intermediate. We separately identify galaxies with features: spiral arms, bars, clumps, rings and dust.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/4433
- Title:
- SDSS Stripe 82 VLA 1-2GHz survey
- Short Name:
- J/MNRAS/460/4433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Karl G. Jansky Very Large Array to image ~100deg^2^ of SDSS Stripe 82 at 1-2GHz. The survey consists of 1026 snapshot observations of 2.5-min duration, using the hybrid CnB configuration. The survey has good sensitivity to diffuse, low surface brightness structures and extended radio emission, making it highly synergistic with existing 1.4GHz radio observations of the region. The principal data products are continuum images, with 16x10 arcsec resolution, and a catalogue containing 11782 point and Gaussian components resulting from fits to the thresholded Stokes-I brightness distribution, forming approximately 8948 unique radio sources. The typical effective 1{sigma} noise level is 88{mu}Jy/beam. Spectral index estimates are included, as derived from the 1GHz of instantaneous bandwidth. Astrometric and photometric accuracy are in excellent agreement with existing narrowband observations. A large-scale simulation is used to investigate clean bias, which we extend into the spectral domain. Clean bias remains an issue for snapshot surveys with the VLA, affecting our total intensity measurements at the ~1{sigma} level. Statistical spectral index measurements are in good agreement with existing measurements derived from matching separate surveys at two frequencies. At flux densities below ~35{sigma} the median in-band spectral index measurements begin to exhibit a bias towards flatness that is dependent on both flux density and the intrinsic spectral index. In-band spectral curvature measurements are likely to be unreliable for all but the very brightest components. Image products and catalogues are publicly available via an FTP server (ftp://ftp.atnf.csiro.au/pub/people/hey036/Stripe82).
- ID:
- ivo://CDS.VizieR/J/ApJ/884/82
- Title:
- SDSS, WISE and HI data of local spiral galaxies
- Short Name:
- J/ApJ/884/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The emerging light from a galaxy is under the influence of its own interstellar medium, as well as its spatial orientation. Considering a sample of 2239 local spiral galaxies in optical (Sloan Digital Sky Survey u, g, r, i, and z) and infrared bands (WISE W1, W1), we study the dependency of the global intrinsic attenuation in spiral galaxies on their morphologies, sizes, and spatial inclinations. Reddening is minimal at the extremes of low mass and gas depletion and maximal in galaxies that are relatively massive and metal-rich and still retain substantial gas reserves. A principal component constructed from observables that monitor galaxy mass, relative H i content to old stars, and infrared surface brightness is strongly correlated with the amplitude of obscuration. We determine both a parametric model for dust obscuration and a nonparametric model based on the Gaussian process formalism. An average dust attenuation curve is derived for wavelengths between 0.36 and 4.5{mu}m.
- ID:
- ivo://CDS.VizieR/VII/264
- Title:
- Second Byurakan Survey galaxies. Optical database
- Short Name:
- VII/264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A database for the entire catalog of the Second Byurakan Survey (SBS) galaxies is presented. It contains new measurements of their optical parameters and additional information taken from the literature and other databases. The measurements were made using Ipg(near-infrared), Fpg(red) and Jpg(blue) band images from photographic sky survey plates obtained by the Palomar Schmidt telescope and extracted from the STScI Digital Sky Survey (DSS). The database provides accurate coordinates, morphological type, spectral and activity classes, apparent magnitudes and diameters, axial ratios, and position angles, as well as number counts of neighboring objects in a circle of radius 50kpc. The total number of individual SBS objects in the database is now 1676. The 188 Markarian galaxies which were re-discovered by SBS are not included in this database. We also include redshifts that are now available for 1576 SBS objects, as well as 2MASS infrared magnitudes for 1117 SBS galaxies.
- ID:
- ivo://CDS.VizieR/VII/276
- Title:
- Second Byurakan Survey. General Catalogue
- Short Name:
- VII/276
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Second Byurakan Survey (SBS) General Catalogue is presented. The SBS, a continuation of the Markarian survey reaching fainter limiting magnitudes, is the first survey which combines the search of galaxies and QSOs. A total area of 991 square degrees of the Northern sky was covered with the use of three objective prisms in combination with Schott filters. The limited magnitude on the best plates reached B~19.5. The General Catalogue consists of 3563 objects presented in two parts: a Catalogue of galaxies (1863 objects) and one of stellar objects (1700 objects). The Catalogue of SBS AGN consists of 761 objects (155 SyG, 596 QSOs, and 10 BLLac). Multi-wavelength data are presented for 1438 SBS objects identified with X-ray, IRAS and FIRST sources. Spectrophotometric observations obtained over 26 years are available for 3132 objects. Redshifts were measured for ~2100 extragalactic objects. Spectral classification is presented for ~2970 objects. The majority of the data is presented here for the first time. The Catalogue presents new large homogeneous deep representative complete samples of bright QSOs, AGNs, and faint UVX galaxies in the Northern sky. The SBS sample is found to be complete at 70% for galaxies and ~85% for AGN/QSOs with B<=17.5.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/3729
- Title:
- Sersic + exponential disc morphologies in Coma
- Short Name:
- J/MNRAS/453/3729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxies are not limited to simple spheroid or bulge + disc morphologies. We explore the diversity of internal galaxy structures in the Coma Cluster across a wide range of luminosities (-17>Mg>-22) and cluster-centric radii (0<r_cluster_<1.3r_200_) through analysis of deep Canada-France-Hawaii Telescope i-band imaging. We present 2D multicomponent decomposition via galfit, encompassing a wide range of candidate model morphologies with up to three photometric components. Particular focus is placed on early-type galaxies with outer discs (i.e. S0s), and deviations from simple ('unbroken') exponential discs. Rigorous filtering ensures that each model component provides a statistically significant improvement to the goodness-of-fit. The majority of Coma Cluster members in our sample (478 of 631) are reliably fitted by symmetric structural models. Of these, 134 (28 percent) are single Sersic objects, 143 (30 percent) are well-described by 2-component structures, while 201 (42 percent) require more complex models. Multicomponent Sersic galaxies resemble compact pseudo-bulges (n~2, R_e_~4kpc) surrounded by extended Gaussian-like outer structures (R_e_>10kpc). 11 percent of galaxies (N=52) feature a break in their outer profiles, indicating 'truncated' or 'antitruncated' discs. Beyond the break radius, truncated galaxies are structurally consistent with exponential discs, disfavouring physical truncation as their formation mechanism. Bulge luminosity in antitruncated galaxies correlates strongly with galaxy luminosity, indicating a bulge-enhancing origin for these systems. Both types of broken disc are found overwhelmingly (>70 percent) in 'barred' galaxies, despite a low measured bar fraction for Coma (20+/-2 percent). Thus, galaxy bars play an important role in formation of broken disc structures. No strong variation in galaxy structure is detected with projected cluster-centric radius.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1750
- Title:
- Seyfert population in SSRS2
- Short Name:
- J/AJ/126/1750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The magnitude-limited catalog of the Southern Sky Redshift Survey (SSRS2, Cat. <J/AJ/116/1>) is used to characterize the properties of galaxies hosting active galactic nuclei (AGNs). Using emission-line ratios, we identify a total of 162 (3%) Seyfert galaxies out of the parent sample with 5399 galaxies. The sample contains 121 Seyfert 2 galaxies and 41 Seyfert 1 galaxies. The SSRS2 Seyfert galaxies are predominantly in spirals of types Sb and earlier or in galaxies with perturbed appearance as the result of strong interactions or mergers. Seyfert galaxies in this sample are twice as common in barred hosts as the non-Seyfert galaxies. By assigning galaxies to groups using a percolation algorithm, we find that the Seyfert galaxies in the SSRS2 are more likely to be found in binary systems when compared with galaxies in the SSRS2 parent sample. However, there is no statistically significant difference between the Seyfert and SSRS2 parent sample when systems with more than two galaxies are considered. The analysis of the present sample suggests that there is a stronger correlation between the presence of the AGN phenomenon with internal properties of galaxies (morphology, presence of bar, luminosity) than with environmental effects (local galaxy density, group velocity dispersion, nearest neighbor distance).
- ID:
- ivo://CDS.VizieR/J/ApJS/172/599
- Title:
- SFI++ II. A new I-band Tully-Fisher catalog
- Short Name:
- J/ApJS/172/599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SFI++ data set, a homogeneously derived catalog of photometric and rotational properties and the Tully-Fisher distances and peculiar velocities derived from them. We make use of digital optical images, optical long-slit spectra, and global HI line profiles to extract parameters of relevance to disk scaling relations, incorporating several previously published data sets as well as a new photometric sample of some 2000 objects. According to the completeness of available redshift samples over the sky area, we exploit both a modified percolation algorithm and the Voronoi-Delaunay method to assign individual galaxies to groups as well as clusters, thereby reducing scatter introduced by local orbital motions. We also provide corrections to the peculiar velocities for both homogeneous and inhomogeneous Malmquist bias, making use of the 2MASS Redshift Survey density field to approximate large-scale structure. The final SFI++ peculiar velocity catalog contains 4861 field and cluster galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/2878
- Title:
- SFR & AGN in most luminous local universe LINERs
- Short Name:
- J/MNRAS/462/2878
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z=0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission-line intensities, extinction, stellar populations, stellar masses, ages, active galactic nuclei (AGN) luminosities, and SFRs. We find considerable differences from other low-redshift LINERs, in terms of extinction, and general similarity to star-forming galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z~0.3 by Tommasin et al. The median stellar mass of these LINERs corresponds to 6-7x10^10^M_{sun}_ which was found in previous work to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN~LSF suggesting co-evolution of black hole and stellar mass. In general, the fraction of local LINERs on the main sequence of star-forming galaxies is related to their AGN luminosity.
