81 research outputs found

    EIGER III. JWST/NIRCam observations of the ultra-luminous high-redshift quasar J0100+2802

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    We present the first rest-frame optical spectrum of a high-redshift quasar observed with JWST/NIRCam in Wide Field Slitless (WFSS) mode. The observed quasar, J0100+2802, is the most luminous quasar known at z>6z>6. We measure the mass of the central supermassive black hole (SMBH) by means of the rest-frame optical Hβ\beta emission line, and find consistent mass measurements of the quasar's SMBH of M1010MM_\bullet\approx10^{10}\,M_\odot when compared to the estimates based on the properties of rest-frame UV emission lines CIV and MgII, which are accessible from ground-based observatories. To this end, we also present a newly reduced rest-frame UV spectrum of the quasar observed with X-Shooter/VLT and FIRE/Magellan for a total of 16.8 hours. We readdress the question whether this ultra-luminous quasar could be effected by strong gravitational lensing making use of the diffraction limited NIRCam images in three different wide band filters (F115W, F200W, F356W), which improves the achieved spatial resolution compared to previous images taken with the Hubble Space Telescope by a factor of two. We do not find any evidence for a foreground deflecting galaxy, nor for multiple images of the quasar, and determine the probability for magnification due to strong gravitational lensing with image separations below the diffraction limit of Δθ0.05\Delta\theta\lesssim 0.05'' to be 2.2×103\lesssim 2.2\times 10^{-3}. Our observations therefore confirm that this quasar hosts a ten billion solar mass black hole less than 11 Gyr after the Big Bang, which is challenging to explain with current black hole formation models.Comment: Accepted for publication in Ap

    EIGER V. Characterizing the Host Galaxies of Luminous Quasars at z6z\gtrsim6

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    We report {\em JWST}/NIRCam measurements of quasar host galaxy emissions and supermassive black hole (SMBH) masses for six quasars at 5.9<z<7.15.9<z<7.1 in the \textit{Emission-line galaxies and Intergalactic Gas in the Epoch of Reionization} (EIGER) project. We obtain deep NIRCam imaging in the F115W, F200W, and F356W bands, as well as F356W grism spectroscopy of the quasars. We use bright unsaturated stars to construct models of the point spread function (PSF) and estimate the errors of these PSFs. We then measure or constrain the fluxes and morphology of the quasar host galaxies by fitting the quasar images as a point source plus an exponential disk. We successfully detect the host galaxy of three quasars, which have host-to-quasar flux ratios of 1%5%\sim1\%-5\%. Spectral Energy Distribution (SED) fitting suggests that these quasar host galaxies have stellar masses of M1010MM_*\gtrsim10^{10}M_\odot. For quasars with host galaxy non-detections, we estimate the upper limits of their stellar masses. We use the grism spectra to measure the {\hb} line profile and the continuum luminosity, then estimate the SMBH masses for the quasars. Our results indicate that the positive relation between SMBH masses and host galaxy stellar masses already exists at redshift z6z\gtrsim6. The quasars in our sample show a high black hole to stellar mass ratio of MBH/M0.15M_\text{BH}/M_*\sim0.15, which is about 12\sim1-2 dex higher than the local relations. This result suggests that luminous quasars at z6z\gtrsim6 form a biased sample with overmassive black holes, which might have experienced early SMBH growth compared to their host galaxies' star formation.Comment: 21 pages, 12 figures, submitted to AAS journals. Comments welcome

    Experimental Evidence for a Spin-Polarized Ground State in the \nu=5/2 Fractional Quantum Hall Effect

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    We study the \nu=5/2 even-denominator fractional quantum Hall effect (FQHE) over a wide range of magnetic (B) field in a heterojunction insulated gate field-effect transistor (HIGFET). The electron density can be tuned from n=0 to 7.6 \times 10^{11} cm^{-2} with a peak mobility \mu = 5.5 \times 10^6 cm^2/Vs. The \nu=5/2 state shows a strong minimum in diagonal resistance and a developing Hall plateau at magnetic fields as high as 12.6T. The strength of the energy gap varies smoothly with B-field. We interpret these observations as strong evidence for a spin-polarized ground state at \nu=5/2.Comment: new references adde

    Possible composite-fermion liquid as a crossover from Wigner crystal to bubble phase in higher Landau level

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    The ground state cohesive energies per electron of the composite fermion (CF) Fermi sea, the Laughlin state and the charge density wave (CDW) at higher Landau levels (LLs) are computed. It is shown that whereas for n2n\geq 2 LL, the CDW state is generally more energetically preferable than those of the CF liquid and the Laughlin liquid, the ν=4+1/6\nu =4+1/6 CF liquid state unexpectedly has lower ground state energy than that of the CDW state. We suggest this CF liquid between the Wigner crystal and the bubble phase may lead to the crossover from the normal integer quantum Hall liquid to the novel re-entrant integer quantum Hall state observed in the recent magneto-transport experiments

    Coulomb drag of Luttinger liquids and quantum-Hall edges

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    We study the transconductance for two coupled one-dimensional wires or edge states described by Luttinger liquid models. The wires are assumed to interact over a finite segment. We find for the interaction parameter g=1/2g=1/2 that the drag rate is finite at zero temperature, which cannot occur in a Fermi-liquid system. The zero temperature drag is, however, cut off at low temperature due to the finite length of the wires. We also consider edge states in the fractional quantum Hall regime, and we suggest that the low temperature enhancement of the drag effect might be seen in the fractional quantum Hall regime.Comment: 5 pages, 2 figures; to appear in Phys. Rev. Let

    Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. II. Evidence for Tidally Enhanced Star Formation and Black Hole Accretion

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    Active galactic nuclei (AGNs) are occasionally seen in pairs, suggesting that tidal encounters are responsible for the accretion of material by both central supermassive black holes (BHs). In Paper I of this series, we selected a sample of AGN pairs with projected separations r_p < 100 kpc and velocity offsets < 600 km/s from the SDSS DR7 and quantified their frequency. In this paper, we address the BH accretion and recent star formation properties in their host galaxies. AGN pairs experience stronger BH accretion, as measured by their [O III]5007 luminosities (corrected for contribution from star formation) and Eddington ratios, than do control samples of single AGNs matched in redshift and host stellar mass. Their host galaxies have stronger post-starburst activity and younger mean stellar ages, as indicated by stronger H-delta absorption and smaller 4000 A break in their spectra. The BH accretion and recent star formation in the host galaxies both increase with decreasing projected separation in AGN pairs, for r_p ~< 10-30 kpc. The intensity of BH accretion, the post-starburst strength, and the mean stellar ages are correlated between the two AGNs in a pair. The luminosities and Eddington ratios of AGN pairs are correlated with recent star formation in their host galaxies, with a scaling relation consistent with that observed in single AGNs. Our results suggest that galaxy tidal interactions enhance both BH accretion and star formation in AGN pairs, even though the majority of low redshift AGNs is not coincident with on-going interactions.Comment: 16 pages, 12 figures; to appear in Ap

    The Demographics of Broad Line Quasars in the Mass-Luminosity Plane II. Black Hole Mass and Eddington Ratio Functions

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    We employ a flexible Bayesian technique to estimate the black hole mass and Eddington ratio functions for Type 1 (i.e., broad line) quasars from a uniformly-selected data set of ~58,000 quasars from the SDSS DR7. We find that the SDSS becomes significantly incomplete at M_{BH} < 3 x 10^8 M_{Sun} or L / L_{Edd} < 0.07, and that the number densities of Type 1 quasars continue to increase down to these limits. Both the mass and Eddington ratio functions show evidence of downsizing, with the most massive and highest Eddington ratio black holes experiencing Type 1 quasar phases first, although the Eddington ratio number densities are flat at z < 2. We estimate the maximum Eddington ratio of Type 1 quasars in the observable Universe to be L / L_{Edd} ~ 3. Consistent with our results in Paper I, we do not find statistical evidence for a so-called "sub-Eddington boundary" in the mass-luminosity plane of broad line quasars, and demonstrate that such an apparent boundary in the observed distribution can be caused by selection effect and errors in virial BH mass estimates. Based on the typical Eddington ratio in a given mass bin, we estimate typical growth times for the black holes in Type 1 quasars and find that they are typically comparable to or longer than the age of the universe, implying an earlier phase of accelerated (i.e., with higher Eddington ratios) and possibly obscured growth. The large masses probed by our sample imply that most of our black holes reside in what are locally early type galaxies, and we interpret our results within the context of models of self-regulated black hole growth.Comment: Submitted to ApJ, 25 pages (emulateapj), 15 figures; revised to match accepted version with primary changes to the introduction and discussion, replaced Fig 1

    Little Red Dots: an abundant population of faint AGN at z5z\sim5 revealed by the EIGER and FRESCO JWST surveys

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    Characterising the prevalence and properties of faint active galactic nuclei (AGN) in the early Universe is key for understanding the formation of supermassive black holes (SMBHs) and determining their role in cosmic reionization. We perform a spectroscopic search for broad Hα\alpha emitters at z46z\approx4-6 using deep JWST/NIRCam imaging and wide field slitless spectroscopy from the EIGER and FRESCO surveys. We identify 20 Hα\alpha lines at z=4.25.5z = 4.2 - 5.5 that have broad components with line widths from 12003700\sim1200 - 3700 km s1^{-1}, contributing 3090\sim 30 - 90 % of the total line flux. We interpret these broad components as being powered by accretion onto SMBHs with implied masses 1078\sim10^{7-8} M_{\odot}. In the UV luminosity range MUV_{\rm UV} = -21 to -18, we measure number densities of 105\approx10^{-5} cMpc3^{-3}. This is an order of magnitude higher than expected from extrapolating quasar UV luminosity functions. Yet, such AGN are found in only <1<1% of star-forming galaxies at z5z\sim5. The SMBH mass function agrees with large cosmological simulations. In two objects we detect narrow red- and blue-shifted Hα\alpha absorption indicative, respectively, of dense gas fueling SMBH growth and outflows. We may be witnessing early AGN feedback that will clear dust-free pathways through which more massive blue quasars are seen. We uncover a strong correlation between reddening and the fraction of total galaxy luminosity arising from faint AGN. This implies that early SMBH growth is highly obscured and that faint AGN are only minor contributors to cosmic reionization.Comment: 23 pages, 17 figures. Submitted to ApJ. Main Figs 4, 10, 15 (faint AGN UV luminosity function) and 16 (SMBH mass function). Fig. 17 summarises the results. Comments welcom

    Cell Type–dependent Requirement for PIP Box–regulated Cdt1 Destruction During S Phase

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    Previous studies have shown that Cdt1 overexpression in cultured cells can trigger re-replication, but not whether CRL4Cdt2-triggered destruction of Cdt1 is required for normal mitotic cell cycle progression in vivo. We demonstrate that PIP box–mediated destruction of Cdt1Dup during S phase is necessary for the cell division cycle in Drosophila
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