17,595 research outputs found

    The Origin of the Intrinsic Scatter in the Relation Between Black Hole Mass and Bulge Luminosity for Nearby Active Galaxies

    Full text link
    We investigate the origin of the intrinsic scatter in the correlation between black hole mass (MBH) and bulge luminosity [L(bulge)] in a sample of 45 massive, local (z < 0.35) type~1 active galactic nuclei (AGNs). We derive MBH from published optical spectra assuming a spherical broad-line region, and L(bulge) from detailed two-dimensional decomposition of archival optical Hubble Space Telescope images. AGNs follow the MBH-L(bulge) relation of inactive galaxies, but the zero point is shifted by an average of \Delta log MBH ~ -0.3 dex. We show that the magnitude of the zero point offset, which is responsible for the intrinsic scatter in the MBH-L(bulge) relation, is correlated with several AGN and host galaxy properties, all of which are ultimately related to, or directly impact, the BH mass accretion rate. At a given bulge luminosity, sources with higher Eddington ratios have lower MBH. The zero point offset can be explained by a change in the normalization of the virial product used to estimate MBH, in conjunction with modest BH growth (~ 10%--40%) during the AGN phase. Galaxy mergers and tidal interactions appear to play an important role in regulating AGN fueling in low-redshift AGNs.Comment: To appear in ApJ; 67 pages, 56 figures, 4 tables, version with full resolution figures at http://users.ociw.edu/mjkim/papers/scatter.pd

    The Angstrom Project Alert System: real-time detection of extragalactic microlensing

    Get PDF
    The Angstrom Project is undertaking an optical survey of stellar microlensing events across the bulge region of the Andromeda Galaxy (M31) using a distributed network of two-meter class telescopes. The Angstrom Project Alert System (APAS) has been developed to identify in real time candidate microlensing and transient events using data from the Liverpool and Faulkes North robotic telescopes. This is the first time that real-time microlensing discovery has been attempted outside of the Milky Way and its satellite galaxies. The APAS is designed to enable follow-up studies of M31 microlensing systems, including searches for gas giant planets in M31. Here we describe the APAS and we present a few example light curves obtained during its commissioning phase which clearly demonstrate its real-time capability to identify microlensing candidates as well as other transient sources.Comment: 4 pages, submitted to ApJ Letter

    On zeros of irreducible characters lying in a normal subgroup

    Get PDF
    [EN] Let N be a normal subgroup of a finite group G. In this paper, we consider the elements g of N such that x(g)¿0 for all irreducible characters x of G. Such an element is said to be non-vanishing in G. Let p be a prime. If all p-elements of N satisfy the previous property, then we prove that N has a normal Sylow p-subgroup. As a consequence, we also study certain arithmetical properties of the G-conjugacy class sizes of the elements of N which are zeros of some irreducible character of G. In particular, if N=G, then new contributions are obtained.The first author is supported by Proyecto Prometeo II/2015/011, Generalitat Valenciana (Spain). The research of the second author is partially funded by the Istituto Nazionale di Alta Matematica - INdAM. The third author acknowledges the predoctoral grant ACIF/2016/170, Generalitat Valenciana (Spain). The first and third authors are also supported by Proyecto PGC2018-096872-B-I00, Ministerio de Ciencia, Innovacion y Universidades (Spain).Felipe Román, MJ.; Grittini, N.; Ortiz-Sotomayor, VM. (2020). On zeros of irreducible characters lying in a normal subgroup. Annali di Matematica Pura ed Applicata (1923 -). 199:1777-1789. https://doi.org/10.1007/s10231-020-00942-1S17771789199Beltrán, A., Felipe, M.J.: Prime powers as conjugacy class lengths of π\pi-elements. Bull. Aust. Math. Soc. 69, 317–325 (2004)Beltrán, A., Felipe, M.J., Malle, G., Moretó, A., Navarro, G., Sanus, L., Solomon, R., Tiep, P.H.: Nilpotent and abelian Hall subgroups in finite groups. Trans. Am. Math. Soc. 368, 2497–2513 (2016)Berkovich, Y., Kazarin, L.S.: Indices of elements and normal structure of finite groups. J. Algebra 283, 564–583 (2005)Bianchi, M., Chillag, D., Lewis, M.L., Pacifici, E.: Character degree graphs that are complete graphs. Proc. Am. Math. Soc. 135, 671–676 (2007)Brough, J., Kong, Q.: On vanishing criteria that control finite group structure II. Bull. Aust. Math. Soc. 98, 251–257 (2018)Brough, J.: Non-vanishing elements in finite groups. J. Algebra 460, 387–391 (2016)Dolfi, S., Pacifici, E., Sanus, L., Spiga, P.: On the orders of zeros of irreducible characters. J. Algebra 321, 345–352 (2009)Grüninger, M.: Two remarks about non-vanishing elements in finite groups. J. Algebra 460, 366–369 (2016)Isaacs, I.M.: Character Theory of Finite Groups. Academic Press Inc., London (1976)Isaacs, I.M., Navarro, G., Wolf, T.R.: Finite group elements where no irreducible character vanishes. J. Algebra 222, 413–423 (1999)Malle, G., Navarro, G.: Characterizing normal Sylow pp-subgroups by character degrees. J. Algebra 370, 402–406 (2012)Malle, G., Navarro, G., Olsson, J.B.: Zeros of characters of finite groups. J. Group Theory 3, 353–368 (2000)The GAP Group: GAP—Groups, Algorithms, and Programming. Version 4.10.0 (2018). http://www.gap-system.or

    Essential self-adjointness for combinatorial Schr\"odinger operators II- Metrically non complete graphs

    Full text link
    We consider weighted graphs, we equip them with a metric structure given by a weighted distance, and we discuss essential self-adjointness for weighted graph Laplacians and Schr\"odinger operators in the metrically non complete case.Comment: Revisited version: Ognjen Milatovic wrote to us that he had discovered a gap in the proof of theorem 4.2 of our paper. As a consequence we propose to make an additional assumption (regularity property of the graph) to this theorem. A new subsection (4.1) is devoted to the study of this property and some details have been changed in the proof of theorem 4.

    The North Ecliptic Pole Wide survey of AKARI: a near- and mid-infrared source catalog

    Get PDF
    We present a photometric catalog of infrared (IR) sources based on the North Ecliptic PoleWide field (NEP-Wide) survey of AKARI, which is an infrared space telescope launched by Japan. The NEP-Wide survey covered 5.4 deg2 area, a nearly circular shape centered on the North Ecliptic Pole, using nine photometric filter-bands from 2 - 25 {\mu}m of the Infrared Camera (IRC). Extensive efforts were made to reduce possible false objects due to cosmic ray hits, multiplexer bleeding phenomena around bright sources, and other artifacts. The number of detected sources varied depending on the filter band: with about 109,000 sources being cataloged in the near-IR bands at 2 - 5 {\mu}m, about 20,000 sources in the shorter parts of the mid-IR bands between 7 - 11 {\mu}m, and about 16,000 sources in the longer parts of the mid-IR bands, with \sim 4,000 sources at 24 {\mu}m. The estimated 5? detection limits are approximately 21 magnitude (mag) in the 2 - 5 {\mu}m bands, 19.5 - 19 mag in the 7 - 11 {\mu}m, and 18.8 - 18.5 mag in the 15 - 24 {\mu}m bands in the AB magnitude scale. The completenesses for those bands were evaluated as a function of magnitude: the 50% completeness limits are about 19.8 mag at 3 {\mu}m, 18.6 mag at 9 {\mu}m, and 18 mag at 18 {\mu}m band, respectively. To construct a reliable source catalog, all of the detected sources were examined by matching them with those in other wavelength data, including optical and ground-based near-IR bands. The final band-merged catalog contains about 114,800 sources detected in the IRC filter bands. The properties of the sources are presented in terms of the distributions in various color-color diagrams.Comment: Accepted for publication in A&A, 23 pages, 27 figure

    Focusing and Compression of Ultrashort Pulses through Scattering Media

    Full text link
    Light scattering in inhomogeneous media induces wavefront distortions which pose an inherent limitation in many optical applications. Examples range from microscopy and nanosurgery to astronomy. In recent years, ongoing efforts have made the correction of spatial distortions possible by wavefront shaping techniques. However, when ultrashort pulses are employed scattering induces temporal distortions which hinder their use in nonlinear processes such as in multiphoton microscopy and quantum control experiments. Here we show that correction of both spatial and temporal distortions can be attained by manipulating only the spatial degrees of freedom of the incident wavefront. Moreover, by optimizing a nonlinear signal the refocused pulse can be shorter than the input pulse. We demonstrate focusing of 100fs pulses through a 1mm thick brain tissue, and 1000-fold enhancement of a localized two-photon fluorescence signal. Our results open up new possibilities for optical manipulation and nonlinear imaging in scattering media
    • …
    corecore