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Deep X-ray surveys by Chandra and XMM-Newton have resolved about 80% of the 2–10 keV cosmic ex-tragalactic X-ray background (CXRB) into point sources, the majority of which are obscured AGN. The ob-scuration might be connected to processes within the host galaxy, possibly the star-formation rate. Here, we use the results of CXRB synthesis calculations as(More)
The relative entropy between the joint probability distribution of backward and forward sequences is used to quantify time asymmetry (or irreversibility) for stationary time series. The parallel with the thermodynamic theory of nonequilibrium steady states allows us to link the degree of asymmetry in the time signal with the distance from equilibrium and(More)
We study the stellar and star formation properties of the host galaxies of 58 X-ray selected AGN in the GOODS portion of the Chandra Deep Field South (CDF-S) region at z ∼ 0.5 − 1.4. The AGN are selected such that their rest-frame UV to near-infrared spectral energy distributions (SEDs) are dominated by stellar emission, i.e., they show a prominent 1.6 µm(More)
We present a search for " weak " Mg ii absorbers [those with W r (2796) < 0.3 ˚ A] in the HIRES/Keck spectra of 26 QSOs. We found 30, of which 23 are newly discovered. The spectra are 80% complete to W r (2796) = 0.02Å and have a cumulative redshift path of ∼ 17.2 for the redshift range 0.4 ≤ z ≤ 1.4. The number of absorbers per unit redshift, dN/dz, is(More)
We present Spitzer Space Telescope imaging observations at 3.6, 4.5, 5.8, 8.0, and 24 m of the SCUBA submillimeter sources and Jy VLA radio sources in a 5 0 ; 5 0 area in the Lockman Hole East region. Out of the $40 SCUBA/ VLA sources in the field, Spitzer counterparts were detected for nearly all except for the few low-weight SCUBA detections. We show that(More)
We use a 24 µm selected sample containing more than 8,000 sources to study the evolution of star-forming galaxies in the redshift range from z = 0 to z ∼ 3. We obtain photometric redshifts for most of the sources in our survey using a method based on empirically-built templates spanning from ultraviolet to mid-infrared wavelengths. The accuracy of these(More)
Determining the properties of starbursts requires spectral diagnostics of their ultraviolet radiation fields, to test whether very massive stars are present. We test several such diagnostics, using new models of line ratio behavior combining Cloudy, Starburst99 and up-to-date spectral atlases (Pauldrach et al. 2001; Hillier & Miller 1998). For six galaxies(More)