885 research outputs found
Petrogenetic interpretation of granitoid rocks using multicationic parameters in the Sanggau Area, Kalimantan Island, Indonesia
Granitoid rock compositions from a range of tectonic environments are plotted on a multicationic diagram, based on major and trace element geochemistry and K-Ar dating. This shows that there is a different tectonic nature, rock affinity and suites. The basement granitoid rocks are ranging from diorite to granite composition. They appear to the products of crystallization differentiation of a calc-alkaline magma of island affinity and range to metaluminous granites, granodiorite and tonalite. The tectonic setting has two kinds which are subduction and post-subduction. The geochemical interpretation, origin and melting of mechanism and tectonic setting shows the types of granitoid are M and I-M type. The basement of granite and granodiorite are a segment of island arc that were happened the Sintang Intrusion as post subduction or syn-collision tectonic setting.
Keywords: Petrogenetic, tectonic, affinity, Sintang Intrusion, Kalimanta
The Megamaser Cosmology Project. III. Accurate Masses of Seven Supermassive Black Holes in Active Galaxies with Circumnuclear Megamaser Disks
Observations of HO masers from circumnuclear disks in active galaxies for
the Megamaser Cosmology Project allow accurate measurement of the mass of
supermassive black holes (BH) in these galaxies. We present the Very Long
Baseline Interferometry (VLBI) images and kinematics of water maser emission in
six active galaxies: NGC~1194, NGC~2273, NGC~2960 (Mrk~1419), NGC~4388,
NGC~6264 and NGC~6323. We use the Keplerian rotation curves of these six
megamaser galaxies, plus a seventh previously published, to determine accurate
enclosed masses within the central pc of these galaxies, smaller than
the radius of the sphere of influence of the central mass in all cases. We also
set lower limits to the central mass densities of between 0.12 and 60 ~pc. For six of the seven disks, the high central
densities rule out clusters of stars or stellar remnants as the central
objects, and this result further supports our assumption that the enclosed mass
can be attributed predominantly to a supermassive black hole. The seven BHs
have masses ranging between 0.76 and 6.510. The BH mass
errors are \%, dominated by the uncertainty of the Hubble constant.
We compare the megamaser BH mass determination with other BH mass measurement
techniques. The BH mass based on virial estimation in four galaxies is
consistent with the megamaser BH mass given the latest empirical value of
, but the virial mass uncertainty is much greater. MCP
observations continue and we expect to obtain more maser BH masses in the
future.Comment: 18 pages, 4 figures. This paper has been submitted to ApJ. An updated
version of this paper will be posted when it gets accepte
Main Constituents and Antidiabetic Properties of Otholobium mexicanum.
Two phenols, bakuchiol (1) and 3-hydroxybakuchiol (2), and two isoflavone glycosides, daidzin (3) and genistin (4) were isolated from Otholobium mexicanum J. W. Grimes (Fabaceae). Moreover, the ability of the raw extract and isolated metabolites to inhibit the enzymes α-amylase and α-glucosidase was evaluated in vitro. In the α-amylase assay, the methanolic extract exhibited a moderate inhibitory activity with an IC50 of 470 μg/mL, while inhibition percentages of bakuchiol (1), 3-hydroxybakuchiol (2), and daidzin (3) were less than 25% at the maximum dose tested (1 μM). Genistin (4) exhibited a poor activity with an IC50 of 805 μM. In the α-glucosidase assay, the methanolic extract exhibited a strong inhibitory activity with an IC50 value of 32 μg/mL, while 3-hydroxybakuchiol (2) exhibited a moderate inhibitory activity with an IC50 of 345 μM. Daidzin (3) and genistin (4) exhibited lower inhibitory activity with IC50 values of 564 μM and 913 μM, respectively. Bakuchiol (1) exhibited a poor inhibitory activity with an inhibition percentage less than 10% at the maximum dose tested (1 mM)
The WiFeS S7 AGN survey: Current status and recent results on NGC 6300
The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) is a
targeted survey probing the narrow-line regions (NLRs) of a representative
sample of ~140 nearby (z<0.02) Seyfert galaxies by means of optical integral
field spectroscopy. The survey is based on a homogeneous data set observed
using the Wide Field Spectrograph WiFeS. The data provide a 25x38 arcsec
field-of-view around the galaxy centre at typically ~1.5 arcsec spatial
resolution and cover a wavelength range between ~3400 - 7100 at spectral
resolutions of ~100 km s and ~50 km s in the blue and red parts,
respectively. The survey is primarily designed to study gas excitation and star
formation around AGN, with a special focus on the shape of the AGN ionising
continuum, the interaction between radio jets and the NLR gas, and the nature
of nuclear LINER emission. We provide an overview of the current status of
S7-based results and present new results for NGC 6300.Comment: 5 pages, 1 figure, Refereed Proceeding of the "The Universe of
Digital Sky Surveys" conference held at the INAF - Observatory of
Capodimonte, Naples, on 25th-28th november 2014, to be published on
Astrophysics and Space Science Proceedings, edited by Longo, Napolitano,
Marconi, Paolillo, Iodic
Probing the Physics of Narrow Line Regions in Active Galaxies III: Accretion and Cocoon Shocks in the LINER NGC1052
We present Wide Field Spectrograph (WiFeS) integral field spectroscopy and
HST FOS spectroscopy for the LINER galaxy NGC 1052. We infer the presence of a
turbulent accretion flow forming a small-scale accretion disk. We find a
large-scale outflow and ionisation cone along the minor axis of the galaxy.
Part of this outflow region is photoionised by the AGN, and shares properties
with the ENLR of Seyfert galaxies, but the inner (~arcsec)
accretion disk and the region around the radio jet appear shock excited. The
emission line properties can be modelled by a "double shock" model in which the
accretion flow first passes through an accretion shock in the presence of a
hard X-ray radiation, and the accretion disk is then processed through a cocoon
shock driven by the overpressure of the radio jets. This model explains the
observation of two distinct densities ( and cm),
and provides a good fit to the observed emission line spectrum. We derive
estimates for the velocities of the two shock components and their mixing
fractions, the black hole mass, the accretion rate needed to sustain the LINER
emission and derive an estimate for the jet power. Our emission line model is
remarkably robust against variation of input parameters, and so offers a
generic explanation for the excitation of LINER galaxies, including those of
spiral type such as NGC 3031 (M81).Comment: Accepted for publication in Astrophysical Journal. 16 pages, 12
figure
Further Closing the Resolution Gap: Integrating Cryo-Soft X-Ray and Light Microscopies
Abstract
Water megamasers from circumnuclear disks in galaxy centers provide the most accurate measurements of supermassive black hole masses and uniquely probe the subparsec accretion processes. At the same time, these systems offer independent crucial constraints of the Hubble constant in the nearby universe, and thus, the arguably best single constraint on the nature of dark energy. The chances of finding these golden standards are, however, abysmally low, at ?3% overall for any level of water maser emission detected at 22 GHz and ?1% for those exhibiting disk-like configuration. We provide here a thorough summary of the current state of detection of water megamaser disks along with a novel investigation of the likelihood of increasing their detection rates based on a multivariate parameter analysis of the optical and mid-infrared (mid-IR) photometric properties of the largest database of galaxies surveyed for 22 GHz emission. We find that galaxies with water megamaser emission tend to be associated with strong emission in all Wide-field Infrared Survey Explorer mid-IR wavelengths, with the strongest enhancement in the W4 band, at 22 μm, as well as with previously proposed and newly found indicators of active galactic nucleus strength in the mid-IR, such as red W1???W2 and W1???W4 colors, and the integrated mid-IR luminosity of the host galaxy. These trends offer a potential boost of the megamaser detection rates to 6%–15%, or a factor of 2–8 relative to the current rates, depending on the chosen sample selection criteria, while fostering real chances for discovering ?20 new megamaser disks
Constraining Sources of Ultra High Energy Cosmic Rays Using High Energy Observations with the Fermi Satellite
We analyze the conditions that enable acceleration of particles to ultra-high
energies, ~10^{20} eV (UHECRs). We show that broad band photon data recently
provided by WMAP, ISOCAM, Swift and Fermi satellites, yield constraints on the
ability of active galactic nuclei (AGN) to produce UHECRs. The high energy (MeV
- GeV) photons are produced by Compton scattering of the emitted low energy
photons and the cosmic microwave background or extra-galactic background light.
The ratio of the luminosities at high and low photon energies can therefore be
used as a probe of the physical conditions in the acceleration site. We find
that existing data excludes core regions of nearby radio-loud AGN as possible
acceleration sites of UHECR protons. However, we show that giant radio lobes
are not excluded. We apply our method to Cen A, and show that acceleration of
protons to ~10^{20} eV can only occur at distances >~ 100 kpc from the core.Comment: Extended discussion on former results; Accepted for publication in
JCA
Large rivers and orogens: the evolution of the Yarlung Tsangpo–Irrawaddy system and the eastern Himalayan syntaxis
The eastern Himalayan syntaxis has experienced some of the highest rates of deformation and erosion in the orogen during the Late Cenozoic, and the Yarlung Tsangpo, Brahmaputra, Irrawaddy, Salween, and Mekong rivers are the key erosional systems in that region. The Yarlung Tsangpo drains southern Tibet and the deep Siang River gorge through the eastern Himalayan syntaxis before joining the Brahmaputra in northeastern India. It has been proposed that the Yarlung Tsangpo drained into other large rivers of southern Asia, such as the Irrawaddy, Salween and Red River. We have used uranium/lead dating and hafnium measurements of detrital zircons from Cenozoic sedimentary deposits in Central Myanmar to demonstrate that the Yarlung Tsangpo formerly drained into the Irrawaddy River in Myanmar through the eastern syntaxis, and that this ancient river system was established by (at least) the Middle–Late Eocene. The Yarlung Tsangpo–Irrawaddy river disconnected in the Early Miocene driven by increased deformation in the eastern syntaxis and headward erosion by tributaries of the Brahmaputra. Our results highlight the significance of the sedimentary record of large orogen-parallel rivers and provide key chronological constraints on landscape evolution during the Early Miocene phase of the Himalayan orogeny
The Megamaser Cosmology Project. III. Accurate Masses of Seven Supermassive Black Holes in Active Galaxies with Circumnuclear Megamaser Disks
Observations of HO masers from circumnuclear disks in active galaxies for
the Megamaser Cosmology Project allow accurate measurement of the mass of
supermassive black holes (BH) in these galaxies. We present the Very Long
Baseline Interferometry (VLBI) images and kinematics of water maser emission in
six active galaxies: NGC~1194, NGC~2273, NGC~2960 (Mrk~1419), NGC~4388,
NGC~6264 and NGC~6323. We use the Keplerian rotation curves of these six
megamaser galaxies, plus a seventh previously published, to determine accurate
enclosed masses within the central pc of these galaxies, smaller than
the radius of the sphere of influence of the central mass in all cases. We also
set lower limits to the central mass densities of between 0.12 and 60 ~pc. For six of the seven disks, the high central
densities rule out clusters of stars or stellar remnants as the central
objects, and this result further supports our assumption that the enclosed mass
can be attributed predominantly to a supermassive black hole. The seven BHs
have masses ranging between 0.76 and 6.510. The BH mass
errors are \%, dominated by the uncertainty of the Hubble constant.
We compare the megamaser BH mass determination with other BH mass measurement
techniques. The BH mass based on virial estimation in four galaxies is
consistent with the megamaser BH mass given the latest empirical value of
, but the virial mass uncertainty is much greater. MCP
observations continue and we expect to obtain more maser BH masses in the
future.Comment: 18 pages, 4 figures. This paper has been submitted to ApJ. An updated
version of this paper will be posted when it gets accepte
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