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[en] Recent studies of the tight scaling relations between the masses of supermassive black holes (BHs) and their host galaxies have suggested that in the past BHs constituted a larger fraction of their host galaxies' mass. However, these arguments are limited by selection effects and difficulties in determining robust host galaxy masses at high redshifts. Here we report the first results of a new, complementary diagnostic route: we directly determine a dynamical host galaxy mass for the z = 1.3 luminous quasar J090543.56+043347.3 through high spatial resolution (0.''47, 4 kpc FWHM) observations of the host galaxy gas kinematics over 30 x 40 kpc using the European Southern Observatory/Very Large Telescope/SINFONI with laser guide star adaptive optics. Combining our result of M_dyn = 2.05^+1.68_-0.74 x 10¹¹ M_sun (within a radius 5.25 ± 1.05 kpc) with M_BH,MgII = 9.02 ± 1.43 x 10⁸ M_sun, M_BH,Hα = 2.83^+1.93_-1.13 x 10⁸ M_sun, we find that the ratio of BH mass to host galaxy dynamical mass for J090543.56+043347.3 matches the present-day relation for M_BH versus M_Bulge,Dyn, well within the IR scatter, and deviating at most by a factor of two from the mean. J090543.56+043347.3 displays clear signs of an ongoing tidal interaction and of spatially extended star formation at a rate of 50-100 M_sun yr^-1, above the cosmic average for a galaxy of this mass and redshift. We argue that its subsequent evolution may move J090543.56+043347.3 even closer to the z = 0 relation for M_BH versus M_Bulge,Dyn. Our results support the picture in which any substantive evolution in these relations must occur prior to z ∼ 1.3. Having demonstrated the power of this modeling approach, we are currently analyzing similar data on seven further objects to better constrain such evolution.

[en] The loss of coherence is one of the main obstacles for the implementation of quantum information processing. The efficiency of dynamical decoupling schemes, which have been introduced to address this problem, is limited itself by the fluctuations in the driving fields which will themselves introduce noise. We address this challenge by introducing the concept of concatenated continuous dynamical decoupling, which can overcome not only external magnetic noise but also noise due to fluctuations in driving fields. We show theoretically that this approach can achieve relaxation limited coherence times, and demonstrate experimentally that already the most basic implementation of this concept yields an order of magnitude improvement to the decoherence time for the electron spin of nitrogen vacancy centers in diamond. The proposed scheme can be applied to a wide variety of other physical systems, including trapped atoms and ions and quantum dots, and may be combined with other quantum technologies challenges such as quantum sensing and quantum information processing. (paper)

[en] Since Januar 1990, 97 patients with locally advanced carcinomas of the naso-, oro-, hypopharynx and the oral cavity in UICC stages III and IV were treated according to an accelerated hyperfractionated radiotherapy schedule with concurrent chemotherapy. The primary tumor and positive lymph nodes received a total dose of 72 Gy in 6 weeks. In the first 3 weeks, large fields were irradiated 5 times per week with 2 Gy per fraction. Thereafter, treatment was accelerated, giving 2 daily fractions of 1.4 Gy with minimal intervals of 6 hours. Target volumes were reduced after 49.6 and 59.4 Gy, excluding clinically uninvolved lymph node regions of low and high risk. On day 1, 350 mg/m² 5-FU and 50 mg/m² folinic acid were given as intravenous bolus followed by continuous infusion of 350 mg/m² 5-FU and 100 mg/m² folinic acid, days 1 to 5. 10 mg/m² mitomycin C was given on day 5 and 36 of the treatment. Salvage surgery was offered for residual disease 5 to 6 weeks after the end of radiotherapy. Patient characteristics: 70 male, 27 female; age: 27 to 81 years; T2/T3/T4: 7/30/60; N0/N1/N2/N3: 20/18/53/6; nasopharynx/oropharynx/hyperpharynx/oral cavity: 16/33/36/12. Median follow-up is 26 months. Overall survival and recurrence-free survival at 2 years were 68±5% and 74±5%. Multivariate analysis revealed a significant influence of the geometric mean neck node diameter of the N-stage on loco-regional control and survival. T-stage, tumor volume, or tumor localisation did not become significant. Acute toxicity of this schedule was acceptable but required optimised supportive care. Treatment related grade 4+ late toxicity of mucosa, soft tissue and bone were observed with a cumulative frequency of 13% at 2 years. Two patients died during a phase of severe leuco- or thrombocytopenia. (orig.)

[en] The star formation rate (SFR) and black hole accretion rate (BHAR) functions are measured to be proportional to each other at z ∼< 3. This close correspondence between SF and BHA would naturally yield a BH mass-galaxy mass correlation, whereas a BH mass-bulge mass correlation is observed. To explore this apparent contradiction, we study the SF in spheroid-dominated galaxies between z = 1 and the present day. We use 903 galaxies from the COMBO-17 survey with M_* > 2 x 10¹⁰ M_sun, ultraviolet and infrared-derived SFRs from Spitzer and Galaxy Evolution Explorer, and morphologies from GEMS Hubble Space Telescope/Advanced Camera for Surveys imaging. Using stacking techniques, we find that <25% of all SF occurs in spheroid-dominated galaxies (Sersic index n > 2.5), while the BHAR that we would expect if the global scalings held is 3 times higher. This rules out the simplest picture of co-evolution, in which SF and BHA trace each other at all times. These results could be explained if SF and BHA occur in the same events, but offset in time, for example at different stages of a merger event. However, one would then expect to see the corresponding star formation activity in early-stage mergers, in conflict with observations. We conclude that the major episodes of SF and BHA occur in different events, with the bulk of SF happening in isolated disks and most BHA occurring in major mergers. The apparent global co-evolution results from the regulation of the BH growth by the potential well of the galactic spheroid, which includes a major contribution from disrupted disk stars.

[en] We report 10 lens candidates in the Extended Chandra Deep Field South from the GEMS survey. Nine of the systems are new detections and only one of the candidates is a known lens system. For the most promising five systems including the known lens system, we present results from preliminary lens mass modeling, which tests if the candidates are plausible lens systems. Photometric redshifts of the candidate lens galaxies are obtained from the COMBO-17 galaxy catalog. Stellar masses of the candidate lens galaxies within the Einstein radius are obtained by using the z-band luminosity and the V-z color-based stellar mass-to-light ratios. As expected, the lensing masses are found to be larger than the stellar masses of the candidate lens galaxies. These candidates have similar dark matter fractions as compared to lenses in SLACS and COSMOS. They also roughly follow the halo-mass-stellar-mass relation predicted by the subhalo abundance matching technique. One of the candidate lens galaxies qualifies as a luminous infrared galaxy and may not be a true lens because the arc-like feature in the system is likely to be an active region of star formation in the candidate lens galaxy. Among the five best candidates, one is a confirmed lens system, one is likely a lens system, two are less likely to be lenses, and the status of one of the candidates is ambiguous. Spectroscopic follow-up of these systems is still required to confirm lensing and/or for more accurate determination of the lens masses and mass density profiles.

[en] We present a study of the host galaxies of active galactic nucleus (AGN) selected from the zCOSMOS survey to establish if accretion onto supermassive black holes (SMBHs) and star formation are explicitly linked up to z ∼ 1. We identify 152 galaxies that harbor AGN, based on their X-ray emission (L _0.5-10keV>10⁴² erg s^-1) detected by XMM-Newton observations of 7543 galaxies (i _acs < 22.5). Star formation rates (SFRs), including those weighted by stellar mass, of a subsample are determined using the [O II]λ3727 emission-line luminosity, corrected for an AGN contribution based on the observed [O III]λ5007 strength or that inferred by their hard (2-10 keV) X-ray luminosity. We find that an overwhelming majority of AGN host galaxies have significant levels of star formation with a distribution spanning ∼1-100 M _sun yr^-1; their average SFR is higher than that of galaxies with equivalent stellar mass (M _*>4 x 10¹⁰ M _sun). The close association between AGN activity and star formation is further substantiated by an increase in the fraction of galaxies hosting AGN with the youthfulness of their stars as indicated by the rest-frame color (U-V) and spectral index D_n (4000); we demonstrate that a mass-selected sample is required to alleviate an artificial peak in the AGN fraction falling in the transition region due to the fact that many 'blue cloud' galaxies have low mass-to-light ratios in luminosity-limited samples. We also find that the SFRs of AGN hosts evolve with cosmic time in a manner that closely mirrors the overall galaxy population and naturally explains the low SFRs in AGNs (z < 0.3) from the SDSS. We conclude that the conditions most conducive for AGN activity are a massive host galaxy and a large reservoir of gas. Furthermore, a direct correlation between mass-accretion rate onto SMBHs and SFR is shown to be weak although the average ratio (∼10^-2) is constant with redshift, effectively shifting the evidence for a co-evolution scenario in a statistical manner to smaller physical scales (i.e., within the same galaxies). The order-of-magnitude increase in this ratio compared to the locally measured value of M _BH/M _bulge is consistent with an AGN lifetime substantially shorter than that of star formation. Our findings illustrate an intermittent scenario with underlying complexities regarding fueling over vastly different physical (and temporal) scales yet to be firmly determined.

[en] The impact of environment on active galactic nucleus (AGN) activity up to z ∼ 1 is assessed by utilizing a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS spectroscopic redshift survey. We identify 147 AGN by their X-ray emission as detected by XMM-Newton from a parent sample of 7234 galaxies. We measure the fraction of galaxies with stellar mass M_* > 2.5 x 10¹⁰ M _sun that host an AGN as a function of local overdensity using the 5th, 10th, and 20th nearest neighbors that cover a range of physical scales (∼1-4 Mpc). Overall, we find that AGNs prefer to reside in environments equivalent to massive galaxies with substantial levels of star formation. Specifically, AGNs with host masses between 0.25 and 1 x 10¹¹ M _sun span the full range of environments (i.e., field to group) exhibited by galaxies of the same mass and rest-frame color or specific star formation rate. Host galaxies having M_* > 10¹¹ M _sun clearly illustrate the association with star formation since they are predominantly bluer than the underlying galaxy population and exhibit a preference for lower-density regions analogous to Sloan Digital Sky Survey studies of narrow-line AGN. To probe the environment on smaller physical scales, we determine the fraction of galaxies (M_* > 2.5 x 10¹⁰ M _sun) hosting AGNs inside optically selected groups, and find no significant difference with field galaxies. We interpret our results as evidence that AGN activity requires a sufficient fuel supply; the probability of a massive galaxy to have retained some sufficient amount of gas, as evidence by its ongoing star formation, is higher in underdense regions where disruptive processes (i.e., galaxy harassment, tidal stripping) are lessened.

[en] The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei (AGN) are primarily triggered during major mergers between gas-rich galaxies. While plausible for decades, this model has only begun to be tested with statistical rigor in the past few years. Here, we report on a Hubble Space Telescope study to test this hypothesis for z = 2 quasars with high supermassive black hole masses ($M_{\mathrm{B}\mathrm{H}}={10}^9\text{--}{10}^{10}{M}_{\odot <!--\; ???\; -->}$ ), which dominate cosmic black hole growth at this redshift. We compare Wide Field Camera 3 $F160W$ (rest-frame V-band) imaging of 19 point source-subtracted quasar hosts to a matched sample of 84 inactive galaxies, testing whether the quasar hosts have greater evidence for strong gravitational interactions. Using an expert ranking procedure, we find that the quasar hosts are uniformly distributed within the merger sequence of inactive galaxies, with no preference for quasars in high-distortion hosts. Using a merger/non-merger cutoff approach, we recover distortion fractions of $f_{\mathrm{m},\mathrm{q}\mathrm{s}\mathrm{o}}=0.39\pm <!--\; ??\; -->0.11$ for quasar hosts and $f_{\mathrm{m},\mathrm{g}\mathrm{a}\mathrm{l}}=0.30\pm <!--\; ??\; -->0.05$ for inactive galaxies (distribution modes, 68% confidence intervals), with both measurements subjected to the same observational conditions and limitations. The slight enhancement in distorted fraction for quasar hosts over inactive galaxies is not significant, with a probability that the quasar fraction is higher $P(f_{\mathrm{m},\mathrm{q}\mathrm{s}\mathrm{o}}><!--\; >\; -->f_{\mathrm{m},\mathrm{g}\mathrm{a}\mathrm{l}})=0.78$ ($0.78\mathrm{\sigma <!--\; ??\; -->}$), in line with results for lower mass and lower z AGN. We find no evidence that major mergers are the primary triggering mechanism for the massive quasars that dominate accretion at the peak of cosmic quasar activity.

[en] We report on a Hubble Space Telescope search for rest-frame ultraviolet emission from the host galaxies of five far-infrared-luminous z ≃ 6 quasars and the z = 5.85 hot-dust-free quasar SDSS J0005–0006. We perform 2D surface brightness modeling for each quasar using a Markov Chain Monte Carlo estimator, to simultaneously fit and subtract the quasar point source in order to constrain the underlying host galaxy emission. We measure upper limits for the quasar host galaxies of m _J > 22.7 mag and m _H > 22.4 mag, corresponding to stellar masses of M _* < 2 × 10¹¹ M _⊙. These stellar mass limits are consistent with the local M _BH − M _* relation. Our flux limits are consistent with those predicted for the UV stellar populations of z ≃ 6 host galaxies, but likely in the presence of significant dust ($⟨<!--\; ???\; -->A_{\mathrm{U}\mathrm{V}}⟩<!--\; ???\; -->\simeq <!--\; ???\; -->2.6$ mag). We also detect a total of up to nine potential z ≃ 6 quasar companion galaxies surrounding five of the six quasars, separated from the quasars by 1.″4–3.″2, or 8.4–19.4 kpc, which may be interacting with the quasar hosts. These nearby companion galaxies have UV absolute magnitudes of −22.1 to −19.9 mag and UV spectral slopes β of −2.0 to −0.2, consistent with luminous star-forming galaxies at z ≃ 6. These results suggest that the quasars are in dense environments typical of luminous z ≃ 6 galaxies. However, we cannot rule out the possibility that some of these companions are foreground interlopers. Infrared observations with the James Webb Space Telescope will be needed to detect the z ≃ 6 quasar host galaxies and better constrain their stellar mass and dust content.