scholarly journals High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data. IV. Luminosity Function from the Fall Equatorial Stripe Sample

2001 ◽  
Vol 121 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Xiaohui Fan ◽  
Michael A. Strauss ◽  
Donald P. Schneider ◽  
James E. Gunn ◽  
Robert H. Lupton ◽  
...  
2019 ◽  
Vol 15 (S359) ◽  
pp. 441-443
Author(s):  
F. S. Lohmann ◽  
A. Schnorr-Müller ◽  
M. Trevisan ◽  
R. Riffel ◽  
N. Mallmann ◽  
...  

AbstractObservations at high redshift reveal that a population of massive, quiescent galaxies (called red nuggets) already existed 10 Gyr ago. These objects undergo a significant size evolution over time, likely due to minor mergers. In this work we present an analysis of local massive compact galaxies to assess if their properties are consistent with what is expected for unevolved red nuggets (relic galaxies). Using integral field spectroscopy (IFS) data from the MaNGA survey from the Sloan Digital Sky Survey (SDSS), we characterized the kinematics and properties of stellar populations of massive compact galaxies, and find that these objects exhibit, on average, a higher rotational support than a control sample of average sized early-type galaxies. This is in agreement with a scenario in which these objects have a quiet accretion history, rendering them candidates for relic galaxies.


2009 ◽  
Vol 137 (5) ◽  
pp. 4118-4126 ◽  
Author(s):  
Naohisa Inada ◽  
Masamune Oguri ◽  
Min-Su Shin ◽  
Issha Kayo ◽  
Michael A. Strauss ◽  
...  

2000 ◽  
Vol 17 (1) ◽  
pp. 56-71 ◽  
Author(s):  
Paul J. Francis ◽  
Matthew T. Whiting ◽  
Rachel L. Webster

AbstractWe present quasi-simultaneous multi-colour optical/near-IR photometry for 157 radio selected quasars, forming an unbiassed sub-sample of the Parkes Flat-Spectrum Sample. Data are also presented for 12 optically selected QSOs, drawn from the Large Bright QSO Survey. The spectral energy distributions of the radio- and optically-selected sources are quite different. The optically selected QSOs are all very similar: they have blue spectral energy distributions curving downwards at shorter wavelengths. Roughly 90% of the radio-selected quasars have roughly power-law spectral energy distributions, with slopes ranging from Fv∝v0 to Fv∝v−2. The remaining 10% have spectral energy distributions showing sharp peaks: these are radio galaxies and highly reddened quasars. Four radio sources were not detected down to magnitude limits of H ∼ 19·6. These are probably high redshift (z > 3) galaxies or quasars. We show that the colours of our red quasars lie close to the stellar locus in the optical: they will be hard to identify in surveys such as the Sloan Digital Sky Survey. If near-IR photometry is added, however, the red power-law sources can be clearly separated from the stellar locus: IR surveys such as 2MASS should be capable of finding these sources on the basis of their excess flux in the K-band.


2020 ◽  
Vol 492 (4) ◽  
pp. 5297-5312 ◽  
Author(s):  
Eliab Malefahlo ◽  
Mario G Santos ◽  
Matt J Jarvis ◽  
Sarah V White ◽  
Jonathan T L Zwart

ABSTRACT We present the radio luminosity function (RLF) of optically selected quasars below 1 mJy, constructed by applying a Bayesian-fitting stacking technique to objects well below the nominal radio flux density limit. We test the technique using simulated data, confirming that we can reconstruct the RLF over three orders of magnitude below the typical 5σ detection threshold. We apply our method to 1.4-GHz flux densities from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey, extracted at the positions of optical quasars from the Sloan Digital Sky Survey over seven redshift bins up to z = 2.15, and measure the RLF down to two orders of magnitude below the FIRST detection threshold. In the lowest redshift bin (0.2 < z < 0.45), we find that our measured RLF agrees well with deeper data from the literature. The RLF for the radio-loud quasars flattens below $\log _{10}[L_{1.4}/{\rm W\, Hz}^{-1}] \approx 25.5$ and becomes steeper again below $\log _{10}[L_{1.4}/{\rm W\, Hz}^{-1}] \approx 24.8$, where radio-quiet quasars start to emerge. The radio luminosity where radio-quiet quasars emerge coincides with the luminosity where star-forming galaxies are expected to start dominating the radio source counts. This implies that there could be a significant contribution from star formation in the host galaxies, but additional data are required to investigate this further. The higher redshift bins show a similar behaviour to the lowest z bin, implying that the same physical process may be responsible.


2019 ◽  
Vol 871 (2) ◽  
pp. 258 ◽  
Author(s):  
Jan-Torge Schindler ◽  
Xiaohui Fan ◽  
Ian D. McGreer ◽  
Jinyi Yang ◽  
Feige Wang ◽  
...  

2019 ◽  
Vol 489 (1) ◽  
pp. 653-662
Author(s):  
Benjamin R Granett ◽  
Ginevra Favole ◽  
Antonio D Montero-Dorta ◽  
Enzo Branchini ◽  
Luigi Guzzo ◽  
...  

ABSTRACT We test the history of structure formation from redshift 1 to today by matching galaxies from the VIMOS Public Extragalactic Redshift Survey (VIPERS) and Sloan Digital Sky Survey (SDSS) with dark matter haloes in the MultiDark, Small MultiDark Planck (SMDPL), N-body simulation. We first show that the standard subhalo abundance matching (SHAM) recipe implemented with MultiDark fits the clustering of galaxies well both at redshift 0 for SDSS and at redshift 1 for VIPERS. This is an important validation of the SHAM model at high redshift. We then remap the simulation time steps to test alternative growth histories and infer the growth index γ = 0.6 ± 0.3. This analysis demonstrates the power of using N-body simulations to forward model galaxy surveys for cosmological inference. The data products and code necessary to reproduce the results of this analysis are available online (https://github.com/darklight-cosmology/vipers-sham).


2009 ◽  
Vol 508 (1) ◽  
pp. 339-344 ◽  
Author(s):  
J. Krzesinski ◽  
S. J. Kleinman ◽  
A. Nitta ◽  
S. Hügelmeyer ◽  
S. Dreizler ◽  
...  

2012 ◽  
Vol 8 (S295) ◽  
pp. 185-185
Author(s):  
A. Ratsimbazafy ◽  
C. Cress ◽  
S. Crawford ◽  

AbstractLuminous Red Galaxies (LRGs) have old, red stellar populations often interpreted as evidence of a formation scenario in which these galaxies form in a single intense burst of star formation at high redshift. By measuring the average age of LRGs at two different redshifts, one can potentially measure the redshift interval corresponding to a time interval and thus measure the Hubble parameter H(z) ≈ −(1 + z)−1 Δ z/Δt (as in Jimenez & Loeb). The goal of this project is to measure directly the expansion rate of the universe at the redshift range 0.1 < z < 1.0 within 3% precision. We explore the age-dating of Sloan Digital Sky Survey LRGs using the stellar population models of Lick absorption line indices after stacking spectra in redshift bins to increase the signal-to-noise. We also use the method of full spectral fitting to measure the ages of LRGs observed with the Southern Africa Large Telescope (SALT).


2006 ◽  
Vol 2 (14) ◽  
pp. 314-315
Author(s):  
Hubert Lampeitl ◽  
Adam G. Riess

AbstractSNe Ia are currently providing the most direct measurements of the accelerated expansion of the Universe and also put constraints on the nature and evolution of the so-called ‘dark energy’. Despite major efforts to increase the number of known high-redshift SNe Ia with reliable distance estimates, two regions in the Hubble diagram remain only sparsely observed. At redshifts z > 1 the limitations of ground-based instruments require the Hubble Space Telescope and its superior angular resolution to get meaningful distance estimates, while at intermediate redshifts (z ≃ 0.2) the large solid angle necessary presents an obstacle to most surveys that can be overcome with the Sloan Digital Sky Survey, SDSS-II.


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