Measuring the Average Evolution of Luminous Galaxies at z<3: The Rest-frame Optical Luminosity Density, Spectral Energy Distribution, and Stellar Mass Density

(Abridged) We present the evolution of the volume averaged properties of the rest-frame optically luminous galaxy population to z~3, determined from four disjoint deep fields with optical to near-infrared wavelength coverage. We select galaxies above a rest-frame V-band luminosity of 3x10^10 Lsol and characterize their rest-frame UV through optical properties via the mean spectral energy distribution (SED). To measure evolution we apply the same selection criteria to a sample of galaxies from the Sloan Digital Sky Survey and COMBO-17. The mean rest-frame 2200Ang through V-band SED becomes steadily bluer with increasing redshift but at z<3 the mean SED falls within the range defined by ``normal'' galaxies in the nearby Universe. We measure stellar mass-to-light ratios (Mstar/L) by fitting models to the rest-frame UV-optical SEDs and derive the stellar mass density. The stellar mass density in luminous galaxies has increased by a factor of 3.5-7.9 from z=3 to z=0.1, including field-to-field variance uncertainties. After correcting to total, the measured mass densities at z<2 lie below the integral of the star formation rate (SFR) density as a function of redshift as derived from UV selected samples. This may indicate a systematic error in the mass densities or SFR(z) estimates. We find large discrepancies between recent model predictions for the evolution of the mass density and our results, even when our observational selection is applied to the models. Finally we determine that Distant Red Galaxies (selected to have J_s - K_s>2.3) in our LV selected samples contribute 30% and 64% of the stellar mass budget at z~2 and z~ 2.8 respectively. These galaxies are largely absent from UV surveys and this result highlights the need for mass selection of high redshift galaxies.Comment: Accepted for publication in the Astrophysical Journal, 24 pages, 16 figure

3D-HST+CANDELS : the evolution of the galaxy size-mass distribution since z=3

Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and we find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, R eff∝(1 + z)–1.48, and moderate evolution for the late-type population, R eff∝(1 + z)-0.75Peer reviewedFinal Accepted Versio

CANDELS: The correlation between galaxy morphology and star formation activity at z~2

We discuss the state of the assembly of the Hubble Sequence in the mix of bright galaxies at redshift 1.4< z \le 2.5 with a large sample of 1,671 galaxies down to H_{AB}~26, selected from the HST/ACS and WFC3 images of the GOODS--South field obtained as part of the GOODS and CANDELS observations. We investigate the relationship between the star formation properties and morphology using various parametric diagnostics, such as the Sersic light profile, Gini (G), M_{20}, Concentration (C), Asymmetry (A) and multiplicity parameters. Our sample clearly separates into massive, red and passive galaxies versus less massive, blue and star forming ones, and this dichotomy correlates very well with the galaxies' morphological properties. Star--forming galaxies show a broad variety of morphological features, including clumpy structures and bulges mixed with faint low surface brightness features, generally characterized by disky-type light profiles. Passively evolving galaxies, on the other hand, very often have compact light distribution and morphology typical of today's spheroidal systems. We also find that artificially redshifted local galaxies have a similar distribution with z~2galaxies in a G-M_{20} plane. Visual inspection between the rest-frame optical and UV images show that there is a generally weak morphological k-correction for galaxies at z~2, but the comparison with non-parametric measures show that galaxies in the rest-frame UV are somewhat clumpier than rest-frame optical. Similar general trends are observed in the local universe among massive galaxies, suggesting that the backbone of the Hubble sequence was already in place at z~2.Comment: 22 pages, 19 figures, ApJ accepted (added 3 references

What do we learn from IRAC observations of galaxies at 2 < z < 3.5?

We analyze very deep HST, VLT and Spitzer photometry of galaxies at 2<z<3.5 in the Hubble Deep Field South. The sample is selected from the deepest public K-band imaging currently available. We show that the rest-frame U-V vs V-J color-color diagram is a powerful diagnostic of the stellar populations of distant galaxies. Galaxies with red rest-frame U-V colors are generally red in rest-frame V-J as well. However, at a given U-V color a range in V-J colors exists, and we show that this allows us to distinguish young, dusty galaxies from old, passively evolving galaxies. We quantify the effects of IRAC photometry on estimates of masses, ages, and the dust content of z>2 galaxies. The estimated distributions of these properties do not change significantly when adding IRAC data to the UBVIJHK photometry. However, for individual galaxies the addition of IRAC can improve the constraints on the stellar populations, especially for red galaxies: uncertainties in stellar mass decrease by a factor of 2.7 for red (U-V > 1) galaxies, but only by a factor of 1.3 for blue (U-V < 1) galaxies. We find a similar color-dependence of the improvement for estimates of age and dust extinction. In addition, the improvement from adding IRAC depends on the availability of full near-infrared JHK coverage; if only K-band were available, the mass uncertainties of blue galaxies would decrease by a more substantial factor 1.9. Finally, we find that a trend of galaxy color with stellar mass is already present at z>2. The most massive galaxies at high redshift have red rest-frame U-V colors compared to lower mass galaxies even when allowing for complex star formation histories.Comment: Accepted for publication in the Astrophysical Journal, 16 pages, 16 figure

Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS

Projected axis ratio measurements of 880 early-type galaxies at redshifts 1<z<2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, the z>1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a~0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z>1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and - at a given mass - on redshift. For present-day and z<1 early-type galaxies the oblate fraction strongly depends on galaxy mass. At z>1 this trend is much weaker over the mass range explored here (10^10<M*/M_sun<10^11), because the oblate fraction among massive (M*~10^11 M_sun) was much higher in the past: 0.59+-0.10 at z>1, compared to 0.20+-0.02 at z~0.1. In contrast, the oblate fraction among low-mass early-type galaxies (log(M*/M_sun)1 to 0.72+-0.06 at z=0. [Abridged]Comment: accepted for publication in ApJ; 14 pages; 10 figures; 4 table

Orbifolded Konishi from the Mirror TBA

Starting with a discussion of the general applicability of the simplified mirror TBA equations to simple deformations of the AdS_5 x S^5 superstring, we proceed to study a specific type of orbifold to which the undeformed simplified TBA equations directly apply. We then use this set of equations, as well as Luscher's approach, to determine the NLO wrapping correction to the energy of what we call the orbifolded Konishi state, and show that they perfectly agree. In addition we discuss wrapping corrections to the ground state energy of the orbifolded model under consideration.Comment: 26 pages, 5 figures, v2: corrected typos, added a short discussion on the ground state of the model; as submitted to J. Phys.

Target-Controlled Infusion of Cefepime in Critically Ill Patients:single center experience

Attainment of appropriate pharmacokinetic-pharmacodynamic (PK-PD) targets for antimicrobial treatment is challenging in critically ill patients, particularly for cefepime, which exhibits a relative narrow therapeutic-toxic window compared to other beta-lactam antibiotics. Target-controlled infusion (TCI) systems, which deliver drugs to achieve specific target drug concentrations, have successfully been implemented for improved dosing of sedatives and analgesics in anesthesia. We conducted a clinical trial in an intensive care unit (ICU) to investigate the performance of TCI for adequate target attainment of cefepime. Twenty-one patients treated with cefepime according to the standard of care were included. Cefepime was administered through continuous infusion using TCI for a median duration of 4.5 days. TCI was based on a previously developed population PK model incorporating the estimated creatinine clearance based on the Cockcroft-Gault formula as the input variable to calculate cefepime clearance. A cefepime blood concentration of 16 mg/liter was targeted. To evaluate the measured versus predicted plasma concentrations, blood samples were taken (median of 10 samples per patient), and total cefepime concentrations were measured using ultraperformance liquid chromatography-tandem mass spectrometry. The performance of the TCI system was evaluated using Varvel criteria. Half (50.3%) of the measured cefepime concentrations were within +/- 30% around the target value of 16 mg liter(-1). The wobble was 11.4%, the median performance error (MdPE) was 21.1%, the median absolute performance error (MdAPE) was 32.0%, and the divergence was -3.72% h(-1). Based on these results, we conclude that TCI is useful for dose optimization of cefepime in ICU patients

III/V-on-lithium niobate amplifiers and lasers

We demonstrate electrically pumped, heterogeneously integrated lasers on thin-film lithium niobate, featuring electro-optic wavelength tunability. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen