We derive improved versions of the relations between supermassive black hole mass (M BH) and host-galaxy bulge velocity dispersion ( sigma ) and luminosity (L; the M- sigma and M-L relations), based ...on 49 M BH measurements and 19 upper limits. Particular attention is paid to recovery of the intrinsic scatter (0) in both relations. We find log(M BH/M ) = alpha + beta log( sigma /200 km s-1) with ( alpha , beta , 0) = (8.12 - 0.08, 4.24 - 0.4,0.44 - 0.06) for all galaxies and ( alpha , beta , 0) = (8.23 - 0.08, 3.96 - 0.4,0.31 - 0.06) for ellipticals. The results for ellipticals are consistent with previous studies, but the intrinsic scatter recovered for spirals is significantly larger. The scatter inferred reinforces the need for its consideration when calculating local black hole mass function based on the M- sigma relation, and further implies that there may be substantial selection bias in studies of the evolution of the M- sigma relation. We estimate the M-L relationship as log(M BH/M ) = alpha + beta log(LV /1011 L ,V ) of ( alpha , beta , 0) = (8.95 - 0.11, 1.11 - 0.1,0.38 - 0.09); using only early-type galaxies. These results appear to be insensitive to a wide range of assumptions about the measurement errors and the distribution of intrinsic scatter. We show that culling the sample according to the resolution of the black hole's sphere of influence biases the relations to larger mean masses, larger slopes, and incorrect intrinsic residuals.
Black hole (BH) masses predicted from the M unk- sigma relationship conflict with predictions from the M unk-L relationship for high-luminosity galaxies, such as brightest cluster galaxies (BCGs). ...The M unk-L relationship predicts that some BCGs may harbor BHs with M unk approaching 10 super(10) M unk, while the M unk- sigma relationship always predicts M unk < 3 x 10 super(0) M unk. we argue that the M unk-L relationship is a plausible description for galaxies of high luminosity. If the cores in central stellar density are formed by binary BHs, the inner core cusp radius, r gamma , may be an independent witness of M unk. Using central structural parameters derived from a large sample of early-type galaxies observed by HST, we argue that L is superior to sigma as an indicator of r gamma . Further, the r gamma -M unk relationship for 11 core galaxies with measured M unk appears to be consistent with the M unk-L relationship for BCGs. BCGs have large cores appropriate for their large luminosities that may be difficult to generate with the more modest BH masses inferred from the M unk- sigma relationship. M unk similar to M would be expected for BCGs, if they were formed in dissipationless mergers, which should preserve the ratio of BH to stellar mass, M. This scenario appears to be consistent with the slow increase in sigma with L and the more rapid increase in effective radii with L seen in BCGs as compared to less luminous galaxies. If BCGs have large BHs commensurate with their luminosities, then the local BH mass function for M unk > 3 x 10 super(0) M unk would be nearly an order of magnitude richer than that inferred from the M unk- sigma relationship. The volume density of the most luminous QSOs may favor the M unk-L relationship.
ABSTRACT
We report the results of decade-long (2008–2018) γ-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, Fermi and Swift data, as well as polarimetric and spectroscopic ...data. The X-ray and γ-ray light curves correlate well, with no delay $\gtrsim 3$ h, implying general cospatiality of the emission regions. The γ-ray–optical flux–flux relation changes with activity state, ranging from a linear to a more complex dependence. The behaviour of the Stokes parameters at optical and radio wavelengths, including 43 GHz Very Long Baseline Array images, supports either a predominantly helical magnetic field or motion of the radiating plasma along a spiral path. Apparent speeds of emission knots range from 10 to 37c, with the highest values requiring bulk Lorentz factors close to those needed to explain γ-ray variability on very short time-scales. The Mg ii emission line flux in the ‘blue’ and ‘red’ wings correlates with the optical synchrotron continuum flux density, possibly providing a variable source of seed photons for inverse Compton scattering. In the radio bands, we find progressive delays of the most prominent light-curve maxima with decreasing frequency, as expected from the frequency dependence of the τ = 1 surface of synchrotron self-absorption. The global maximum in the 86 GHz light curve becomes less prominent at lower frequencies, while a local maximum, appearing in 2014, strengthens toward decreasing frequencies, becoming pronounced at ∼5 GHz. These tendencies suggest different Doppler boosting of stratified radio-emitting zones in the jet.
We present observations of 77 early-type galaxies imaged with the PC1 CCD of the Hubble Space Telescope (HST) WFPC2. 'Nuker-law' parametric fits to the surface brightness profiles are used to ...classify the central structure into 'core' or 'power-law' forms. Core galaxies are typically rounder than power-law galaxies. Nearly all power-law galaxies with central ellipticities >= 0.3 have stellar disks, implying that disks are present in power-law galaxies with < 0.3 but are not visible because of unfavorable geometry. A few low-luminosity flattened core galaxies also have disks; these may be transition forms from power-law galaxies to more luminous core galaxies, which lack disks. Several core galaxies have strong isophote twists interior to their break radii, although power-law galaxies have interior twists of similar physical significance when the photometric perturbations implied by the twists are evaluated. Central color gradients are typically consistent with the envelope gradients; core galaxies have somewhat weaker color gradients than power-law galaxies. Nuclei are found in 29% of the core galaxies and 60% of the power-law galaxies. Nuclei are typically bluer than the surrounding galaxy. While some nuclei are associated with active galactic nuclei (AGNs), just as many are not; conversely, not all galaxies known to have a low-level AGN exhibit detectable nuclei in the broadband filters. NGC 4073 and 4382 are found to have central minima in their intrinsic starlight distributions; NGC 4382 resembles the double nucleus of M31. In general, the peak brightness location is coincident with the photocenter of the core to a typical physical scale of <1 pc. Five galaxies, however, have centers significantly displaced from their surrounding cores; these may be unresolved asymmetric double nuclei. Finally, as noted by previous authors, central dust is visible in about half of the galaxies. The presence and strength of dust correlates with nuclear emission; thus, dust may outline gas that is falling into the central black hole. The prevalence of dust and its morphology suggest that dust clouds form, settle to the center, and disappear repeatedly on ~108 yr timescales. We discuss the hypothesis that cores are created by the decay of a massive black hole binary formed in a merger. Apart from their brightness profiles, there are no strong differences between core galaxies and power-law galaxies that demand this scenario; however, the rounder shapes of core, their lack of disks, and their reduced color gradients may be consistent with it.
Aims. Since the CGRO operation in 1991–2000, one of the primary unresolved questions about the blazar γ-ray emission has been its possible correlation with the low-energy (in particular optical) ...emission. To help answer this problem, the Whole Earth Blazar Telescope (WEBT) consortium has organized the GLAST-AGILE Support Program (GASP) to provide the optical-to-radio monitoring data to be compared with the γ-ray detections by the AGILE and GLAST satellites. This new WEBT project started in early September 2007, just before a strong γ-ray detection of 0716+714 by AGILE. Methods. We present the GASP-WEBT optical and radio light curves of this blazar obtained in July–November 2007, about various AGILE pointings at the source. We construct NIR-to-UV spectral energy distributions (SEDs), by assembling GASP-WEBT data together with UV data from the Swift ToO observations of late October. Results. We observe a contemporaneous optical-radio outburst, which is a rare and interesting phenomenon in blazars. The shape of the SEDs during the outburst appears peculiarly wavy because of an optical excess and a UV drop-and-rise. The optical light curve is well sampled during the AGILE pointings, showing prominent and sharp flares. A future cross-correlation analysis of the optical and AGILE data will shed light on the expected relationship between these flares and the γ-ray events.
PKS 0521−36 is an active galactic nucleus (AGN) with uncertain classification. We investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ...ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spectrum radio quasars (SSRQ). On pc-scales PKS 0521−36 shows a knotty structure similar to misaligned AGN. The core dominance and the γ-ray properties are similar to those estimated for other SSRQ and BLRG detected in γ-rays, suggesting an intermediate viewing angle with respect to the observer. In this context the flaring activity detected from this source by Fermi-Large Area Telescope between 2010 June and 2012 February is very intriguing. We discuss the γ-ray emission of this source in the framework of the structured jet scenario, comparing the spectral energy distribution (SED) of the flaring state in 2010 June with that of a low state. We present three alternative models corresponding to three different choices of the viewing angles θv = 6°, 15°, and 20°. We obtain a good fit for the first two cases, but the SED obtained with θv = 15° if observed at a small angle does not resemble that of a typical blazar since the synchrotron emission should dominate by a large factor (∼100) the inverse Compton component. This suggests that a viewing angle between 6° and 15° is preferred, with the rapid variability observed during γ-ray flares favouring a smaller angle. However, we cannot rule out that PKS 0521−36 is the misaligned counterpart of a synchrotron-dominated blazar.
We combine several HST investigations on the central structure of early-type galaxies to generate a large sample of surface photometry. The studies selected were those that used the "Nuker law" to ...characterize the inner light distributions of the galaxies. The sample comprises WFPC1 and WFPC2 V-band observations published earlier by our group, R-band WFPC2 photometry of Rest et al., NICMOS H-band photometry by Ravindranath et al. and Quillen et al., and the brightest cluster galaxy WFPC2 I-band photometry of Laine et al. The distribution of the logarithmic slopes of the central brightness profiles strongly affirms that the central structure of elliptical galaxies with M sub(v) < -19 is bimodal, based on both parametric and nonparametric analysis. At the HST resolution limit, most galaxies are either power-law systems, which have steep cusps in surface brightness, or core systems, which have shallow cusps interior to a steeper envelope brightness distribution. A rapid transition between the two forms occurs over the luminosity range -22 < M sub(v) < -20, with cores dominating at the highest luminosities and power laws at the lowest. There are a few "intermediate" systems that have both cusp slopes and total luminosities that fall within the core/power-law transition, but they are rare and do not fill in the overall bimodal distribution.
Primary cilia are organelles that are present on many different cell types, either transiently or permanently. They play a crucial role in receiving signals from the environment and passing these ...signals to other parts of the cell. In that way, they are involved in diverse processes such as adipocyte differentiation and olfactory sensation. Mutations in genes coding for ciliary proteins often have pleiotropic effects and lead to clinical conditions, ciliopathies, with multiple symptoms. In this study, we reviewed observations from ciliopathies with obesity as one of the symptoms. It shows that variation in cilia-related genes is itself not a major cause of obesity in the population but may be a part of the multifactorial aetiology of this complex condition. Both common polymorphisms and rare deleterious variants may contribute to the obesity risk. Genotype–phenotype relationships have been noticed. Among the ciliary genes, obesity differs with regard to severity and age of onset, which may relate to the influence of each gene on the balance between pro- and anti-adipogenic processes. Analysis of the function and location of the proteins encoded by these ciliary genes suggests that obesity is more linked to activities at the basal area of the cilium, including initiation of the intraflagellar transport, but less to the intraflagellar transport itself. Regarding the role of cilia, three possible mechanistic processes underlying obesity are described: adipogenesis, neuronal food intake regulation and food odour perception.
Tyrosyl-DNA phosphodiesterase I (Tdp1) hydrolyzes phosphodiester-linked adducts from both ends of DNA. This includes the topoisomerase I (TOP1)-DNA covalent reaction intermediate that is the target ...of the camptothecin class of chemotherapeutics. Tdp1 two-step catalysis is centered on the formation of a Tdp1-DNA covalent complex (Tdp1cc) using two catalytic histidines. Here, we examined the role of the understudied, structurally undefined, and poorly conserved N-terminal domain (NTD) of Tdp1 in context of full-length protein in its ability to remove TOP1cc in cells. Using toxic Tdp1 mutants, we observed that the NTD is critical for Tdp1's ability to remove TOP1-DNA adducts in yeast. Full-length and N-terminal truncated Tdp1 mutants showed similar expression levels and cellular distribution yet an inversed TOP1-dependent toxicity. Single turnover catalysis was significantly different between full-length and truncated catalytic mutants but not wild-type enzyme, suggesting that Tdp1 mutants depend on the NTD for catalysis. These observations suggest that the NTD plays a critical role in the regulation of Tdp1 activity and interaction with protein-DNA adducts such as TOP1cc in cells. We propose that the NTD is a regulatory domain and coordinates stabilization of the DNA-adducted end within the catalytic pocket to access the phosphodiester linkage for hydrolysis.
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