- ID:
- ivo://CDS.VizieR/J/MNRAS/350/1485
- Title:
- 2dFGRS: Radio galaxies properties
- Short Name:
- J/MNRAS/350/1485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The clustering properties of local, S_1.4GHz_>=1mJy, radio sources are investigated for a sample of 820 objects drawn from the joint use of the Faint Images of the Radio Sky at 20cm (FIRST, <VIII/71>) and 2dF Galaxy Redshift surveys (<VII/223>, <VII/226>). To this aim, we present 271 new b_J_<=19.45mag spectroscopic counterparts of FIRST radio sources to be added to those already introduced in our previous paper.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/352/939
- Title:
- 2dFGRS Wiener reconstruction of cosmic web
- Short Name:
- J/MNRAS/352/939
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reconstruct the underlying density field of the Two-degree Field Galaxy Redshift Survey (2dFGRS, <VII/226>) for the redshift range 0.035<z<0.200 using the Wiener filtering method. The Wiener filter suppresses shot noise and accounts for selection and incompleteness effects. The method relies on prior knowledge of the 2dF power spectrum of fluctuations and the combination of matter density and bias parameters, however the results are only slightly affected by changes to these parameters. We present maps of the density field. We use a variable smoothing technique with two different effective resolutions: 5 and 10h^-1^Mpc at the median redshift of the survey. We identify all major superclusters and voids in the survey. In particular, we find two large superclusters and two large local voids. The full set of colour maps can be viewed on the World Wide Web at http://www.ast.cam.ac.uk/~pirin .
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5524
- Title:
- Discovering Large-Scale Structure in ORELSE Survey
- Short Name:
- J/MNRAS/491/5524
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey is an ongoing imaging and spectroscopic campaign initially designed to study the effects of environment on galaxy evolution in high-redshift (z~1) large-scale structures. We use its rich data in combination with a powerful new technique, Voronoi tessellation Monte-Carlo (VMC) mapping, to search for serendipitous galaxy overdensities at 0.55<z<1.37 within 15 ORELSE fields, a combined spectroscopic footprint of ~1.4 square degrees. Through extensive tests with both observational data and our own mock galaxy catalogs, we optimize the method's many free parameters to maximize its efficacy for general overdensity searches. Our overdensity search yielded 402 new overdensity candidates with precisely measured redshifts and an unprecedented sensitivity down to low total overdensity masses M_tot_>5*10^13^M_{sun}_). Using the mock catalogs, we estimated the purity and completeness of our overdensity catalog as a function of redshift, total mass, and spectroscopic redshift fraction, finding impressive levels of both 0.92/0.83 and 0.60/0.49 for purity/completeness at z=0.8 and z=1.2, respectively, for all overdensity masses at spectroscopic fractions of ~20%. With VMC mapping, we are able to measure precise systemic redshifts, provide an estimate of the total gravitating mass, and maintain high levels of purity and completeness at z~1 even with only moderate levels of spectroscopy. Other methods (e.g., red-sequence overdensities and hot medium reliant detections) begin to fail at similar redshifts, which attests to VMC mapping's potential to be a powerful tool for current and future wide-field galaxy evolution surveys at z~1 and beyond.
- ID:
- ivo://CDS.VizieR/J/MNRAS/361/109
- Title:
- Distant cluster galaxies Tully-Fisher relation
- Short Name:
- J/MNRAS/361/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured maximum rotation velocities (Vrot) for a sample of 111 emission-line galaxies with 0.1~<z~<1, observed in the fields of six clusters. From these data we construct 'matched' samples of 58 field and 22 cluster galaxies, covering similar ranges in redshift (0.25<=z<=1.0) and luminosity (M_B_<=-19.5mag), and selected in a homogeneous manner.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/482
- Title:
- DLA system from SDSS DR5
- Short Name:
- J/MNRAS/435/482
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the chemical abundance measurements of the first large, medium-resolution, uniformly selected damped Lyman {alpha} system (DLA) survey. The sample contains 99 DLAs towards 89 quasars selected from the SDSS DR5 DLA sample in a uniform way. We analyse the metallicities and kinematic diagnostics, including the velocity width of 90 percent of the optical depth, {Delta}V_90_, and the equivalent widths of the SiII {lambda}1526 (W}{lambda}1526), CIV {lambda}1548 and MgII {lambda}2796 transitions. To avoid strong line-saturation effects on the metallicities measured in medium-resolution spectra (FWHM~71km/s), we derived metallicities from metal transitions which absorbed at most 35 percent of the quasar continuum flux. We find the evolution in cosmic mean metallicity of the sample, <Z>=(-0.04+/-0.13)z-(1.06+/-0.36), consistent with no evolution over the redshift range z~[2.2, 4.4], but note that the majority of our sample falls at z~[2.2, 3.5]. The apparent lack of metallicity evolution with redshift is also seen in a lack of evolution in the median {Delta}V_90_ and W{lambda}1526 values. While this result may seem to conflict with other large surveys that have detected significant metallicity evolution, such as Rafelski et al. who found <Z>=(-0.22+/-0.03)z-(0.65+/-0.09) over z~[0, 5], several tests show that these surveys are not inconsistent with our new result. However, over the smaller redshift range covered by our uniformly selected sample, the true evolution of the cosmic mean metallicity in DLAs may be somewhat flatter than the Rafelski et al. (2012ApJ...755...89R, Cat. J/ApJ/755/89) estimate.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/2985
- Title:
- Double-lobed radio sources catalog
- Short Name:
- J/MNRAS/446/2985
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Current wide-area radio surveys are dominated by active galactic nuclei, yet many of these sources have no identified optical counterparts. Here we investigate whether one can constrain the nature and properties of these sources, using Fanaroff-Riley type II (FR II) radio galaxies as probes. These sources are easy to identify since the angular separation of their lobes remains almost constant at some tens of arcseconds for z>1. Using a simple algorithm applied to the Faint Images of the Radio Sky at Twenty-cm survey, we obtain the largest FR II sample to date, containing over 104 double-lobed sources. A subset of 459 sources is matched to Sloan Digital Sky Survey quasars. This sample yields a statistically meaningful description of the fraction of quasars with lobes as a function of redshift and luminosity. This relation is combined with the bolometric quasar luminosity function and a disc-lobe correlation to obtain a robust prediction for the density of FR IIs on the radio sky. We find that the observed density can be explained by the population of known quasars, implying that the majority of powerful jets originate from a radiatively efficient accretion flow with a linear jet-disc coupling. Finally, we show that high-redshift jets are more often quenched within 100kpc, suggesting a higher efficiency of jet-induced feedback into their host galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/300/417
- Title:
- Durham/UKST Galaxy Redshift Survey
- Short Name:
- J/MNRAS/300/417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the radial velocities and blue, optical magnitudes for all of the galaxies within the Durham/UKST Galaxy Redshift Survey. This catalogue consists of ~2500 galaxy redshifts to a limiting apparent magnitude of B_J_~17mag, covering a ~1500deg^2^ area around the South Galactic Pole. The galaxies in this survey were selected from the Edinburgh/Durham Southern Galaxy Catalogue and were sampled, in order of apparent magnitude, at a rate of one galaxy in every three. The spectroscopy was performed at the 1.2-m UK Schmidt Telescope in Australia using the FLAIR multi-object spectrograph. We show that our radial velocity measurements made with this instrument have an empirical accuracy of +/-150km/s. The observational techniques and data reduction procedures used in the construction of this survey are also discussed. This survey demonstrates that the UKST can be used to make a three-dimensional map of the large-scale galaxy distribution, via a redshift survey to b_J_~17mag, over a wide area of the sky.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/383
- Title:
- E+A and companion galaxies
- Short Name:
- J/MNRAS/390/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on our intensive spectroscopic campaign with the GoldCam spectrograph on the Kitt Peak National Observatory (KPNO) 2.1-m telescope, we have constructed the first catalogue of E+A galaxies with spectroscopic companion galaxies, and investigated a probability that an E+A galaxy has close companion galaxies. We selected 660 E+A galaxies with 4.0{AA}<H{delta} EW at a redshift of <0.167 from the Data Release 5 of the Sloan Digital Sky Survey (SDSS). We selected their companion candidates from the SDSS imaging data, and classified them into true companions, fore/background galaxies and companion candidates using the SDSS and our KPNO spectra. We observed 26 companion candidates of E+A galaxies at the KPNO to measure their redshifts. Their spectra showed that 17 targets are true companion galaxies.
- ID:
- ivo://CDS.VizieR/J/other/RAA/15.1414
- Title:
- E+A galaxy candidates in LAMOST DR2
- Short Name:
- J/other/RAA/15.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 70 E+A galaxies is selected from 37206 galaxies in the second data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). This sample is selected according to the criteria for E+A galaxies defined by Goto, and each of these objects is further visually identified. In this sample, most objects are low redshift E+A galaxies with z<0.25, and are located in an area of the sky with high Galactic latitude and magnitude from 14 to 18mag in the g, r and i bands. A stellar population analysis of the whole sample indicates that the E+A galaxies are characterized by both young and old stellar populations (SPs), and the metal-rich SPs have relatively higher contributions than the metal-poor ones. Additionally, a morphological classification of these objects is performed based on images taken from the Sloan Digital Sky Survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/422
- Title:
- Early-type BCGs with star formation
- Short Name:
- J/MNRAS/423/422
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a total of 120 early-type brightest cluster galaxies (BCGs) at 0.1<z<0.4 in two recent large cluster catalogues selected from the Sloan Digital Sky Survey (SDSS). They are selected with strong emission lines in their optical spectra, with both H{alpha} and [OII]{lambda}3727 line emission, which indicates significant ongoing star formation. They constitute about ~0.5 per cent of the largest, optically selected, low-redshift BCG sample, and the fraction is a strong function of cluster richness. Their star formation history can be well described by a recent minor and short starburst superimposed on an old stellar component, with the recent episode of star formation contributing on average only less than 1 per cent of the total stellar mass. We show that the more massive star-forming BCGs in richer clusters tend to have higher star formation rate (SFR) and specific SFR (SFR per unit galaxy stellar mass). We also compare their statistical properties with a control sample selected from X-ray luminous clusters, and show that the fraction of star-forming BCGs in X-ray luminous clusters is almost one order of magnitude larger than that in optically selected clusters. BCGs with star formation in cooling flow clusters usually have very flat optical spectra and show the most active star formation, which may be connected with cooling flows.
