- ID:
- ivo://CDS.VizieR/J/MNRAS/406/382
- Title:
- Early-type galaxies in the SDSS Stripe82
- Short Name:
- J/MNRAS/406/382
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the properties of "peculiar" early-type galaxies (ETGs) in the local Universe that show (faint) morphological signatures of recent interactions such as tidal tails, shells and dust lanes. Standard-depth (~51s exposure) multicolour galaxy images from the Sloan Digital Sky Survey (SDSS) are combined with the significantly (~2mag) deeper monochromatic images from the public SDSS Stripe82 (-50{deg}<{alpha}<59{deg}, -1.25{deg}<{delta}<1.25{deg}) to extract, through careful visual inspection, a robust sample of nearby (z<0.05), luminous (M_r_<-20.5) ETGs, including a subset of ~70 peculiar systems. ~18% of ETGs exhibit signs of disturbed morphologies (e.g. shells), while ~7% show evidence of dust lanes and patches. An analysis of optical emission-line ratios indicates that the fraction of peculiar ETGs that are Seyferts or LINERs (19.4%) is twice the corresponding values in their relaxed counterparts (10.1%). LINER-like emission is the dominant type of nebular activity in all ETG classes, plausibly driven by stellar photoionization associated with recent star formation. An analysis of ultraviolet-optical colours indicates that, regardless of the luminosity range being considered, the fraction of peculiar ETGs that have experienced star formation in the last Gyr is a factor of ~1.5 higher than that in their relaxed counterparts. The spectrophotometric results strongly suggest that the interactions that produce the morphological peculiarities also induce low-level recent star formation which, based on the recent literature, are likely to contribute a few per cent of the stellar mass over the last ~1Gyr. Peculiar ETGs preferentially inhabit low-density environments (outskirts of clusters, groups or the field), either due to high peculiar velocities in clusters making merging unlikely or because shell systems are disrupted through frequent interactions within a cluster crossing time.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/327/1004
- Title:
- Early-type galaxy parameters
- Short Name:
- J/MNRAS/327/1004
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a series of comparisons between distance-independent photometric and spectroscopic properties used in the surface brightness fluctuation (SBF) and fundamental plane (FP) methods of early-type galaxy distance estimation. The data are taken from two recent surveys: the SBF Survey of Galaxy Distances and the Streaming Motions of Abell Clusters (SMAC) FP survey. We derive a relation between (V-I)0 colour and Mg2 index using nearly 200 galaxies and discuss implications for Galactic extinction estimates and early-type galaxy stellar populations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/274/1071
- Title:
- Edinburgh-Milano cluster redshift survey
- Short Name:
- J/MNRAS/274/1071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the redshifts of the galaxies and galaxy clusters which form the Edinburgh-Milano (EM) cluster redshift survey. A total of 777 galaxy redshifts have been measured in 94 clusters extracted from the digitized Edinburgh-Durham Cluster Catalogue. We also present the radial velocity dispersions for 37 clusters. Observational and data reduction techniques are discussed in detail, together with the strategy adopted to determine the mean redshift of a cluster and to identify and discard plausible phantom clusters. Some 10 per cent of our clusters show heavy contamination, indicating that projection is a serious problem for optically selected, rich clusters. The median velocity dispersion estimated for a subsample of richness R>=1 clusters is 742+/-63km/s. From a simple comparison with {OMEGA}=1 cold dark matter models of structure formation, these results favour a biasing parameter b=1.6-2.0 and are inconsistent with a bias outside of the range b=1.3-2.5.
- ID:
- ivo://CDS.VizieR/J/MNRAS/292/499
- Title:
- EFAR photometric data
- Short Name:
- J/MNRAS/292/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present R-band CCD photometry for 776 galaxies observed in the EFAR (Elliptical FAR away) project. The photometry is compared with photoelectric data, showing that a common zero-point good to better than 1% and a precision of 0.03mag per zero-point have been achieved. We give the circularly averaged surface brightness profiles and the photometric parameters of the 762 program galaxies, D(n) diameters (at 20.5mag/arcsec^2^), half-luminosity radii Re, total magnitudes m_T_, and average effective surface brightnesses <SBe>. More than 80% of the profiles have a global S/N ratio larger than 300. The extrapolation needed to derive total magnitudes is less than 10% for 80% of the fits. More than 80% of the galaxies have mean effective surface brightness larger than the observed sky brightness. In 90% of the profiles the estimate of the contamination of the sky by the galaxy light is less than 1%. We derive total magnitudes and half-luminosity radii to better than 0.15mag and 25%, respectively, for 90% of our sample. In contrast, external comparisons show that data in the literature can be strongly affected by systematic errors due to large extrapolations, small radial range, sky subtraction errors, seeing effects, and the use of a simple R^1/4^ fit. The resulting errors can easily amount to more than 0.5mag in the total magnitudes and 50% in the half-luminosity radii.
- ID:
- ivo://CDS.VizieR/J/MNRAS/351/1290
- Title:
- ELAIS: final band-merged catalogue
- Short Name:
- J/MNRAS/351/1290
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog represents the final band-merged European Large-Area ISO Survey (ELAIS) Catalogue at 6.7, 15, 90 and 175{mu}m, and the associated data at U, g', r', i', Z, J, H, K and 20cm. Details about the origin of the survey, the observations, data reduction and optical identification are described in the paper. In addition to fluxes in the radio, infrared and optical passbands, spectroscopic redshifts are tabulated, where available. For the N1 and N2 areas, the Isaac Newton Telescope ugriz Wide Field Survey permits photometric redshifts to be estimated for galaxies and quasars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/210
- Title:
- eMERGE Survey. I. VLA 5.5GHz sources
- Short Name:
- J/MNRAS/471/210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the GOODS-N field obtained at 5.5GHz with the Karl G. Jansky Very Large Array. The central region of the field was imaged to a median rms of 3{mu}Jy/beam with a resolution of 0.5 arcsec. From a 14-arcmin diameter region, we extracted a sample of 94 radio sources with signal-to-noise ratio greater than 5. Near-IR identifications are available for about ~88 per cent of the radio sources. We used different multiband diagnostics to separate active galactic nuclei (AGNs), both radiatively efficient and inefficient, from star-forming galaxies. From our analysis, we find that about 80 per cent of our radio-selected sample is AGN dominated, with the fraction rising to 92 per cent when considering only the radio sources with redshift >1.5. This large fraction of AGN-dominated radio sources at very low flux densities (the median flux density at 5.5GHz is 42{mu}Jy), where star-forming galaxies are expected to dominate, is somewhat surprising and at odds with other results. Our interpretation is that both the frequency and angular resolution of our radio observations strongly select against radio sources whose brightness distribution is diffuse on a scale of several kpc. Indeed, we find that the median angular sizes of the AGN-dominated sources is around 0.2-0.3arcsec against 0.8 arcsec for star-forming galaxies. This highlights the key role that high frequency radio observations can play in pinpointing AGN-driven radio emission at {mu}Jy levels. This work is part of the eMERGE legacy project.
- ID:
- ivo://CDS.VizieR/J/MNRAS/365/454
- Title:
- Emission line analysis of HII galaxies
- Short Name:
- J/MNRAS/365/454
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical study of a very large sample of HII galaxies taken from the literature. We focus on the differences in several properties between galaxies that show the auroral line [OIII]{lambda}4363 and those that do not present this feature in their spectra.
- ID:
- ivo://CDS.VizieR/J/A+AS/116/43
- Title:
- Emission-line galaxies nearby voids.
- Short Name:
- J/A+AS/116/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the observational results of our search for emission-line galaxies (ELG) towards nearby voids. In order to find ELG, we started a survey using the IIIa-J objective prism plates from the Hamburg QSO Survey. The plates are digitized and an automatic procedure was applied to select the candidates. Digitized direct plates were used to determine coordinates and to reject overlaps between spectra. The accuracy of the coordinates is +/-2". A total area of 1248deg^2^ was scanned, distributed in four different regions. All the selected objects were observed with follow-up spectroscopy. We have obtained a final sample of 203 objects, of which 196 are emission-line galaxies, four are galaxies with absorption lines and three are QSOs. Almost half of our objects are newly discovered ones and three quarters of the given redshifts are new. Our sample contains mainly high ionization galaxies and is less sensitive in the detection of low-ionization objects. The apparent magnitudes, as derived from the objective prism plates, range between 15.0<=B<=19.5. The sample is dominated by nearby galaxies, with a peak in the redshift distribution at cz=4500 km/s.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/83
- Title:
- ESO Imaging Survey. VII.
- Short Name:
- J/A+AS/137/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper the list of candidate clusters identified from the I-band images of the ESO Imaging Survey (EIS) is completed using the data obtained over a total area of about 12 square degrees (EIS Patches C and D). 248 new cluster candidates are presented. Together with the data reported earlier the total I-band coverage of EIS is 17 square degrees, which has yielded a sample of 302 cluster candidates with estimated redshift in the range 0.2<=z<=1.3 and a median redshift of z=0.5. This is the largest optically-selected sample currently available in the Southern Hemisphere. It is also well distributed in the sky thus providing targets for a variety of VLT programs nearly year round.
- ID:
- ivo://CDS.VizieR/J/MNRAS/275/1102
- Title:
- Evolution of quasar luminosity function
- Short Name:
- J/MNRAS/275/1102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In an earlier paper (Hawkins & Veron, 1993MNRAS.260..202H) we presented quasar luminosity functions in three redshift bins, derived from a variability selected sample. Here we provide a major extension to this survey, with a view to improving statistics and completeness, and extending the redshift range. The luminosity functions for redshifts of less than 2.2 show a featureless power law of the form {phi}=10^{beta}(M-M_0_)^, with no sign of a 'break'. The quasar luminosity function is also derived by the redshift range 2.2<z<3.2, which again shows a featureless power law, but with a steeper slope. When the data are combined with a new sample of bright quasars, the quasar luminosity functions in all four redshift ranges are consistent with a single power law of index {beta}=0.63. Plots of quasar space density as a function of redshift in three luminosity bins are also presented and show strong evolution at low redshift but nearly constant space density beyond a redshift of 2.
