349 research outputs found
The broad-band X-ray spectrum of the Seyfert 1 galaxy, MCG+8-11-11
We present a long (100 ks) Suzaku observation of one of the X-ray brightest
AGN, MCG+8-11-11. These data were complemented with the 54-month Swift BAT
spectrum, allowing us to perform a broad-band fit in the 0.6-150 keV range. The
fits performed in the 0.6-10 keV band give consistent results with respect to a
previous XMM-Newton observation, i.e. the lack of a soft excess, warm
absorption along the line of sight, a large Compton reflection component (R~1)
and the absence of a relativistic component of the neutral iron K
emission line. However, when the PIN and Swift BAT data are included, the
reflection amount drops significantly (R~0.2-0.3), and a relativistic iron line
is required, the latter confirmed by a phenomenological analysis in a
restricted energy band (3-10 keV). When a self-consistent model is applied to
the whole broadband data, the observed reflection component appears to be all
associated to the relativistic component of the iron K line. The
resulting scenario, though strongly model-dependent, requires that all the
reprocessing spectral components from Compton-thick material must be associated
to the accretion disc, and no evidence for the classical pc-scale torus is
found. The narrow core of the neutral iron K line is therefore produced
in a Compton-thin material, like the BLR, similarly to what found in another
Seyfert galaxy, NGC7213, but with the notable difference that MCG+8-11-11
presents spectral signatures from an accretion disc. The very low accretion
rate of NGC7213 could explain the lack of relativistic signatures in its
spectrum, but the absence of the torus in both sources is more difficult to
explain, since their luminosities are comparable, and their accretion rates are
completely different.Comment: 8 pages, 6 figure, accepted for publication in Astronomy and
Astrophysic
Deficiency of Broad Line AGNs in Compact Groups of Galaxies
Based on a new survey of AGN activity in Compact Groups of Galaxies, we
report a remarkable deficiency of Broad Line AGNs as compared to Narrow Line
AGNs. The cause of such deficiency could be related to the average low
luminosity of AGNs in CGs: erg s. This result may imply lower
accretion rates in CG AGNs, making Broad Line Regions (BLR) undetectable, or
may indicate a genuine absence of BLRs. Both phenomena are consistent with gas
stripping through tidal interaction and dry mergers.Comment: Accepted for publication in ApJ Lette
XMM-Newton observation of the bright Seyfert 1 galaxy, MCG+8-11-11
We report on the XMM-Newton observation of the bright Seyfert 1 galaxy,
MCG+8-11-11. Data from the EPIC/p-n camera, the Reflection Gratings
Spectrometers (RGS) and the Optical Monitor (OM) have been analyzed. The p-n
spectrum is well fitted by a power law, a spectrally unresolved Fe Kalpha line,
a Compton reflection component (whose large value, when compared to the iron
line equivalent width, suggests iron underabundance), and absorption by warm
material. Absorption lines are apparent in the RGS spectra, but their
identification is uncertain and would require large matter velocities. The UV
fluxes measured by the OM are well above the extrapolation of the X-ray
spectrum, indicating the presence of a UV bump.Comment: 7 pages. Accepted for publication in Astronomy & Astrophysic
Search for astronomical neutrinos from blazar TXS 0506+056 in super-kamiokande
We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 Ă 10â7 and 4.5 Ă 10â7â9.3 Ă 10â10 [erg cmâ2 sâ1], respectively
Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds
The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and KrĂŒppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting
Molecular liver cancer prevention in cirrhosis by organ transcriptome analysis and lysophosphatidic acid pathway inhibition
Cirrhosis is a milieu that develops hepatocellular carcinoma (HCC), the second most lethal cancer worldwide. HCC prediction and prevention in cirrhosis are key unmet medical needs. Here we have established an HCC risk gene signature applicable to all major HCC etiologies: hepatitis B/C, alcohol, and non-alcoholic steatohepatitis. A transcriptome meta-analysis of >500 human cirrhotics revealed global regulatory gene modules driving HCC risk and the lysophosphatidic acid pathway as a central chemoprevention target. Pharmacological inhibition of the pathway in vivo reduced tumors and reversed the gene signature, which was verified in organotypic ex vivo culture of patient-derived fibrotic liver tissues. These results demonstrate the utility of clinical organ transcriptome to enable a strategy, namely, reverse-engineering precision cancer prevention
Altered balance of interleukin-13/interferon-gamma contributes to lacrimal gland destruction and secretory dysfunction in CD25 knockout model of Sjögrenâs syndrome
Search for astronomical neutrinos from blazar TXS 0506+056 in Super-Kamiokande
We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 Ă 10â7 and 4.5 Ă 10â7â9.3 Ă 10â10 [erg cmâ2 sâ1], respectively
Search for proton decay into three charged leptons in 0.37 megaton-years exposure of the Super-Kamiokande
A search for proton decay into three charged leptons has been performed by using 0.37 Mtonâ
years of data collected in Super-Kamiokande. All possible combinations of electrons, muons, and their antiparticles consistent with charge conservation were considered as decay modes. No significant excess of events has been found over the background, and lower limits on the proton lifetime divided by the branching ratio have been obtained. The limits range between 9.2Ă10^33 and 3.4Ă10^34 years at 90% confidence level, improving by more than an order of magnitude upon limits from previous experiments. A first limit has been set for the pâÎŒ^âe^+e^+ mode
Atmospheric neutrino oscillation analysis with improved event reconstruction in Super-Kamiokande IV
A new event reconstruction algorithm based on a maximum likelihood method has been developed for Super-Kamiokande. Its improved kinematic and particle identification capabilities enable the analysis of atmospheric neutrino data in a detector volume 32% larger than previous analyses and increase the sensitivity to the neutrino mass hierarchy. Analysis of a 253.9 ktonâ
â
year exposure of the Super-Kamiokande IV atmospheric neutrino data has yielded a weak preference for the normal hierarchy, disfavoring the inverted hierarchy at 74% assuming oscillations at the best fit of the analysis
- âŠ