The K20 survey

We present the first analysis of large-scale clustering from the Spitzer Wide-area Infrared Extragalactic legacy survey (SWIRE). We compute the angular correlation function of galaxies selected to have 3.6 m fluxes brighter than 32 Jy in three fields totaling 2 deg 2 in area. In each field we detect clustering with a high level of significance. The amplitude and slope of the correlation function is consistent between the three fields and is modeled as w( ) ¼ A 1À with A ¼ (0:6 AE 0:3) ; 10 À3 ; ¼ 2:03 AE 0:10. With a fixed slope of ¼ 1:8, we obtain an amplitude of A ¼ (1:7 AE 0:1) ; 10 À3 . Assuming an equivalent depth of K % 18:7 mag we find that our errors are smaller but our results are consistent with existing clustering measurements in K-band surveys and with stable clustering models. We estimate our median redshift z ' 0:75, and this allows us to obtain an estimate of the three-dimensional correlation function (r), for which we find r 0 ¼ 4:4 AE 0:1 h À1 Mpc.

show abstract

“…In Figure 3 we compare the model with the observed redshift distribution from the K20 sample (Cimatti et al 2002). The shape is a reasonable fit.…”

Section: Estimation Of Three-dimensional Clusteringgmentioning

confidence: 71%

“…All data have fixed ¼ 1:8 except for those of Maller et al (2003), who found % 1:76, depending on scale. The lines are the evolving models of Roche et al (2003) (Cimatti et al 2002) compared with the model of Xu et al (2003). From the model we show starbursts (dashed curve), spheroids (dotted curve), and total counts (solid curve).…”

Section: Discussionmentioning

confidence: 99%

Angular Clustering of Galaxies at 3.6 Microns from theSpitzerWide‐area Infrared Extragalactic (SWIRE) Survey

Oliver

Waddington

González-Solares

et al. 2004

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

show abstract

“…K20 sample. The starting sample consists of about 500 galaxies selected in the K-band from a sub-area of the Chandra Deep Field South (CDFS)/ GOODS-South and from a field around the quasar 0055-2659 [40]. Optical spectra were obtained with the ESO VLT UT1 and UT2 equipped respectively with FORS1 and FORS2.…”

Section: Sample Selectionmentioning

confidence: 99%

Improved constraints on the expansion rate of the Universe up to z ∼ 1.1 from the spectroscopic evolution of cosmic chronometers

Moresco

Cimatti

Jiménez

et al. 2012

J. Cosmol. Astropart. Phys.

712

365

View full text Add to dashboard Cite

Abstract. We present new improved constraints on the Hubble parameter H(z) in the redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic evolution of early-type galaxies as a function of redshift. We extract a large sample of early-type galaxies (∼ 11000) from several spectroscopic surveys, spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We select the most massive, red elliptical galaxies, passively evolving and without signature of ongoing star formation. Those galaxies can be used as standard cosmic chronometers, as firstly proposed by Jimenez & Loeb (2002), whose differential age evolution as a function of cosmic time directly probesWe analyze the 4000Å break (D4000) as a function of redshift, use stellar population synthesis models to theoretically calibrate the dependence of the differential age evolution on the differential D4000, and estimate the Hubble parameter taking into account both statistical and systematical errors.We provide 8 new measurements of H(z) (see Tab. 4), and determine its change in H(z) to a precision of 5 − 12% mapping homogeneously the redshift range up to z ∼ 1.1; for the first time, we place a constraint on H(z) at z = 0 with a precision comparable with the one achieved for the Hubble constant (about 5-6% at z ∼ 0.2), and covered a redshift range (0.5 < z < 0.8) which is crucial to distinguish many different quintessence cosmologies.These measurements have been tested to best match a ΛCDM model, clearly providing a statistically robust indication that the Universe is undergoing an accelerated expansion. This method shows the potentiality to open a new avenue in constrain a variety of alternative cosmologies, especially when future surveys (e.g. Euclid) will open the possibility to extend it up to z ∼ 2.-1 -

show abstract

“…The K20 survey resulted in the observation of a significant high redshift tail of 1.7 < z < 2.3 galaxies with bright near-IR magnitudes (K V ega < 20, [3]). Fig.…”

Section: Fires K20mentioning

confidence: 99%

“…[3] for relative references). As they appear to be actively star-forming, just like LBGs, it is interesting to assess whether these K-selected galaxies are just a special subsample (the brightest tip of the iceberg) of LBGs, or a different population.…”

Section: Fires K20mentioning

confidence: 99%

Tracing the Formation of Massive Spheroids from High-z Galaxy Clustering

Daddi

Multiwavelength Mapping of Galaxy Formation and Evolution

View full text Add to dashboard Cite

Abstract. The high-z progenitors of local massive early-type galaxies should be characterized by a strong level of clustering, larger than that measured for z = 3 Lyman Break Galaxies and comparable to that of z ∼ 1 EROs. First possible evidences for such strongly clustered objects at z > ∼ 2 were found by the FIRES and K20 surveys, that have identified new classes of faint high-z K-selected galaxies. Some details are given here for the new population of massive star-forming galaxies at z ∼ 2, found by the K20 survey in the GOODS-South area. Because of their much redder UV continuum, most of these galaxies would not be selected by the Lyman Break criterion. Such objects are good candidates for the precursors of local ellipticals caught in their formation phase. We have calibrated a two color criterion to allow the identification of these highest redshift galaxies in bright K-limited samples.

show abstract

The K20 survey

Cited by 126 publications

References 29 publications

Angular Clustering of Galaxies at 3.6 Microns from theSpitzerWide‐area Infrared Extragalactic (SWIRE) Survey

Angular Clustering of Galaxies at 3.6 Microns from theSpitzerWide‐area Infrared Extragalactic (SWIRE) Survey

Improved constraints on the expansion rate of the Universe up to z ∼ 1.1 from the spectroscopic evolution of cosmic chronometers

Tracing the Formation of Massive Spheroids from High-z Galaxy Clustering

Contact Info

Product

Resources

About