92 research outputs found

    Elastic properties of the Non-Fermi liquid metal CeRu4Sb12Ce Ru_4 Sb_{12} and the Dense Kondo semiconductor CeOs4Sb12Ce Os_4 Sb_{12}

    Get PDF
    We have investigated the elastic properties of the Ce-based filled skutterudite antimonides CeRu4_{4}Sb12_{12} and CeOs4_{4}Sb12_{12} by means of ultrasonic measurements. CeRu4_{4}Sb12_{12} shows a slight increase around 130 K in the temperature dependence of the elastic constants CC11_{11}, (CC11_{11}-CC12_{12})/2 and CC44_{44}. No apparent softening toward low temperature due to a quadrupolar response of the 4ff-electronic ground state of the Ce ion was observed at low temperatures. In contrast CeOs4_{4}Sb12_{12} shows a pronounced elastic softening toward low temperature in the longitudinal CC11_{11} as a function of temperature (TT) below about 15 K, while a slight elastic softening was observed in the transverse CC44_{44} below about 1.5 K. Furthermore, CeOs4_{4}Sb12_{12} shows a steep decrease around a phase transition temperature of 0.9 K in both CC11_{11} andC C44_{44}. The elastic softening observed in CC11_{11} below about 15 K cannot be explained reasonably only by the crystalline electric field effect. It is most likely to be responsible for the coupling between the elastic strain and the quasiparticle band with a small energy gap in the vicinity of Fermi level. The elastic properties and the 4ff ground state of Ce ions in CeRu4_{4}Sb12_{12} and CeOs4_{4}Sb12_{12} are discussed from the viewpoint of the crystalline electric field effect and the band structure in the vicinity of Fermi level.Comment: 9 pages, 11 figures, regular pape

    Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) VIII. A less biased view of the early co-evolution of black holes and host galaxies

    Get PDF
    We present ALMA [CII] line and far-infrared (FIR) continuum observations of three z>6z > 6 low-luminosity quasars (M1450>−25M_{\rm 1450} > -25) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The [CII] line was detected in all three targets with luminosities of (2.4−9.5)×108 L⊙(2.4 - 9.5) \times 10^8~L_\odot, about one order of magnitude smaller than optically luminous (M1450≲−25M_{\rm 1450} \lesssim -25) quasars. The FIR continuum luminosities range from <9×1010 L⊙< 9 \times 10^{10}~L_\odot (3σ\sigma limit) to ∼2×1012 L⊙\sim 2 \times 10^{12}~L_\odot, indicating a wide range in star formation rates in these galaxies. Most of the HSC quasars studied thus far show [CII]/FIR luminosity ratios similar to local star-forming galaxies. Using the [CII]-based dynamical mass (MdynM_{\rm dyn}) as a surrogate for bulge stellar mass (MbulgeM_{\rm bulge}), we find that a significant fraction of low-luminosity quasars are located on or even below the local MBH−MbulgeM_{\rm BH} - M_{\rm bulge} relation, particularly at the massive end of the galaxy mass distribution. In contrast, previous studies of optically luminous quasars have found that black holes are overmassive relative to the local relation. Given the low luminosities of our targets, we are exploring the nature of the early co-evolution of supermassive black holes and their hosts in a less biased way. Almost all of the quasars presented in this work are growing their black hole mass at much higher pace at z∼6z \sim 6 than the parallel growth model, in which supermassive black holes and their hosts grow simultaneously to match the local MBH−MbulgeM_{\rm BH} - M_{\rm bulge} relation at all redshifts. As the low-luminosity quasars appear to realize the local co-evolutionary relation even at z∼6z \sim 6, they should have experienced vigorous starbursts prior to the currently observed quasar phase to catch up with the relation.Comment: 19 pages, 11 figures, 4 tables. Accepted for publication in Publications of the Astronomical Society of Japan (PASJ

    Small airway disease associated with Sjögren’s syndrome: Clinico-pathological correlations

    Get PDF
    SummaryBackgroundRelationships among clinical, physiological, imaging and pathological findings of small airway disease associated with Sjögren’s syndrome have remained unclear.Subjects and methods: We retrospectively studied 14 patients who underwent surgical lung biopsy and who were diagnosed with small airway disease associated with primary or secondary Sjögren’s syndrome. We compared clinical, bronchoalveolar lavage, physiological, imaging and pathological findings between primary and secondary Sjögren’s syndrome. We scored HRCT and pathological abnormalities and investigated correlations among physiological, HRCT and pathological data, changes in physiological parameters and in HRCT scores after two years of treatment, as well as correlations between these values and pathological scores.ResultsBronchoalveolar lavage fluid, physiological, imaging and pathological findings of the airways did not significantly differ between primary and secondary Sjögren’s syndrome. Air trapping on HRCT negatively correlated with MEF50 and MEF25. Although lymphoid cell infiltration and peribronchiolar fibrosis were the most common pathologies, constrictive change scores correlated negatively with MEF50 and MEF25, positively with air trapping scores and negatively with improvements after therapy in MEF50, MEF25 and air trapping.ConclusionsConstrictive change was the most significant determinant of physiological and imaging presentations and of changes in these factors after therapy for small airway disease associated with Sjögren’s syndrome

    Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) III. Star formation properties of the host galaxies at z≳6z \gtrsim 6 studied with ALMA

    Get PDF
    We present our ALMA Cycle 4 measurements of the [CII] emission line and the underlying far-infrared (FIR) continuum emission from four optically low-luminosity (M1450>−25M_{\rm 1450} > -25) quasars at z≳6z \gtrsim 6 discovered by the Subaru Hyper Suprime Cam (HSC) survey. The [CII] line and FIR continuum luminosities lie in the ranges L[CII]=(3.8−10.2)×108 L⊙L_{\rm [CII]} = (3.8-10.2) \times 10^8~L_\odot and LFIR=(1.2−2.0)×1011 L⊙L_{\rm FIR} = (1.2-2.0) \times 10^{11}~L_\odot, which are at least one order of magnitude smaller than those of optically-luminous quasars at z≳6z \gtrsim 6. We estimate the star formation rates (SFR) of our targets as ≃23−40 M⊙ yr−1\simeq 23-40~M_\odot ~{\rm yr}^{-1}. Their line and continuum-emitting regions are marginally resolved, and found to be comparable in size to those of optically luminous quasars, indicating that their SFR or likely gas mass surface densities (key controlling parameter of mass accretion) are accordingly different. The L[CII]/LFIRL_{\rm [CII]}/L_{\rm FIR} ratios of the hosts, ≃(2.2−8.7)×10−3\simeq (2.2-8.7) \times 10^{-3}, are fully consistent with local star-forming galaxies. Using the [CII] dynamics, we derived their dynamical masses within a radius of 1.5-2.5 kpc as ≃(1.4−8.2)×1010 M⊙\simeq (1.4-8.2) \times 10^{10}~M_\odot. By interpreting these masses as stellar ones, we suggest that these faint quasar hosts are on or even below the star-forming main sequence at z∼6z \sim 6, i.e., they appear to be transforming into quiescent galaxies. This is in contrast to the optically luminous quasars at those redshifts, which show starburst-like properties. Finally, we find that the ratios of black hole mass to host galaxy dynamical mass of the most of low-luminosity quasars including the HSC ones are consistent with the local value. The mass ratios of the HSC quasars can be reproduced by a semi-analytical model that assumes merger-induced black hole-host galaxy evolution.Comment: 20 pages, 9 figures, 4 tables. Accepted for publication in PAS

    Anomalous elastic softening of SmRu_{4}P_{12} under high pressure

    Get PDF
    The filled skutterudite compound SmRu_4P_{12} undergoes a complex evolution from a paramagnetic metal (phase I) to a probable multipolar ordering insulator (phase II) at T_{MI} = 16.5 K, then to a magnetically ordered phase (phase III) at T_{N} = 14 K. Elastic properties under hydrostatic pressures were investigated to study the nature of the ordering phases. We found that distinct elastic softening above T_{MI} is induced by pressure, giving evidence of quadrupole degeneracy of the ground state in the crystalline electric field. It also suggests that quadrupole moment may be one of the order parameters below T_{MI} under pressure. Strangely, the largest degree of softening is found in the transverse elastic constant C_{T} at around 0.5-0.6 GPa, presumably having relevancy to the competing and very different Gruneisen parameters \Omega of T_{MI} and T_{N}. Interplay between the two phase transitions is also verified by the rapid increase of T_{MI} under pressure with a considerably large \Omega of 9. Our results can be understood on the basis of the proposed octupole scenario for SmRu_4P_{12}.Comment: 7 pages, 7 figure

    Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). XIII. Large-scale Feedback and Star Formation in a Low-luminosity Quasar at z = 7.07 on the Local Black Hole to Host Mass Relation

    Get PDF
    We present Atacama Large Millimeter/submillimeter Array [C II] 158 μm line and underlying far-infrared (FIR) continuum emission observations (0 70 × 0 56 resolution) toward HSC J124353.93+010038.5 (J1243+0100) at z = 7.07, the only low-luminosity (M1450 > −25 mag) quasar currently known at z > 7. The FIR continuum is bright (1.52 mJy) and resolved with a total luminosity of LFIR = 3.5 × 1012 Le. The spatially extended component is responsible for ∼40% of the emission. The area-integrated [C II] spectrum shows a broad wing (FWHM = 997 km s−1 , L[C II] = 1.2 × 109 Le), as well as a bright core (FWHM = 235 km s−1 , L[C II] = 1.9 × 109 Le). This wing is the first detection of a galactic-scale quasar-driven outflow (atomic outflow rate >447 Me yr−1 ) at z > 7. The estimated large mass-loading factor of the total outflow (e.g., 9 relative to the [C II]-based star formation rate) suggests that this outflow will soon quench the star formation of the host. The core gas dynamics are governed by rotation, with a rotation curve suggestive of a compact bulge (∼3.3 × 1010 Me), although it is not yet spatially resolved. Finally, we found that J1243+0100 has a black hole mass–to–dynamical mass (and –to–bulge mass) ratio of ∼0.4% (∼1%), consistent with the local value within the uncertainties. Our results therefore suggest that the black hole–host coevolution relation is already in place at z ∼ 7 for this object
    • …
    corecore