Matches in SemOpenAlex for { <https://semopenalex.org/work/W2040698264> ?p ?o ?g. }
- W2040698264 endingPage "157" @default.
- W2040698264 startingPage "150" @default.
- W2040698264 abstract "BeppoSAX observed the Seyfert 1.9 galaxy NGC 4258 in 1998 December, when its 2-10 keV luminosity was about 1041 ergs s-1. Large amplitude (100%) variability is observed in the 3-10 keV band on timescales of a few tens of thousands of seconds, while variability of ~20% is observed on timescales as short as 1 hr. The nuclear component is visible above 2 keV only, being obscured by a column density of (9.5 ± 1.2) × 1022 cm-2; this component is detected at up to 70 keV with a signal-to-noise ratio of 3 and with a steep power-law energy spectral index of αE = 1.11 ± 0.14. Bremsstrahlung emission for the 2-70 keV X-ray luminosity, as expected in advection-dominated accretion flow models with strong winds, is ruled out by the data. The ratio between the nuclear radio (22 GHz) luminosity and the X-ray (5 keV) luminosity is consistent with that of radio-quiet quasars and Seyfert galaxies. X-ray variability, spectral shape, and radio/X-ray and near-IR/X-ray luminosity ratios suggest that the nucleus of NGC 4258 could be a scaled down version of a Seyfert nucleus and that the X-ray nuclear luminosity can be explained in terms of Comptonization in a hot corona. The soft (E 2 keV) X-ray emission is complex. There are at least two thermal-like components with temperatures of 0.6 ± 0.1 keV and 1.3 keV. The cooler (L0.1-2.4 keV~ 1040 ergs s-1) component is probably associated with the jet, resolved in X-rays by the ROSAT HRI (Cecil et al. 1994). The luminosity of the second component, which can be modeled equally well by an unobscured power-law model with αE = 0.2, is L0.1-2.4 keV~ 7 × 1039 ergs s-1, consistent with that expected from discrete X-ray sources (binaries and supernova remnants) in the host galaxy. Observations of NGC 4258 and other maser active galactic nuclei (AGNs) show strong nuclear X-ray absorption. We propose that this large column of gas might be responsible for shielding the regions of water maser emission from X-ray illumination. So a large column density absorbing gas may be a necessary property of masing AGNs." @default.
- W2040698264 created "2016-06-24" @default.
- W2040698264 creator A5002705012 @default.
- W2040698264 creator A5026031896 @default.
- W2040698264 creator A5039428199 @default.
- W2040698264 creator A5044482994 @default.
- W2040698264 creator A5047273464 @default.
- W2040698264 creator A5051825718 @default.
- W2040698264 creator A5062576211 @default.
- W2040698264 creator A5064367137 @default.
- W2040698264 creator A5072745684 @default.
- W2040698264 creator A5082342035 @default.
- W2040698264 creator A5089596748 @default.
- W2040698264 creator A5091245996 @default.
- W2040698264 date "2001-07-20" @default.
- W2040698264 modified "2023-10-16" @default.
- W2040698264 title "TheBeppoSAXView of the X‐Ray Active Nucleus of NGC 4258" @default.
- W2040698264 cites W1481574112 @default.
- W2040698264 cites W1556084648 @default.
- W2040698264 cites W1725123724 @default.
- W2040698264 cites W1939616856 @default.
- W2040698264 cites W1965475297 @default.
- W2040698264 cites W1968646907 @default.
- W2040698264 cites W1981598975 @default.
- W2040698264 cites W1984375310 @default.
- W2040698264 cites W1986383725 @default.
- W2040698264 cites W1988722437 @default.
- W2040698264 cites W1997313837 @default.
- W2040698264 cites W1999883030 @default.
- W2040698264 cites W2008777461 @default.
- W2040698264 cites W2014061258 @default.
- W2040698264 cites W2022146599 @default.
- W2040698264 cites W2033875501 @default.
- W2040698264 cites W2040207916 @default.
- W2040698264 cites W2049319759 @default.
- W2040698264 cites W2050444942 @default.
- W2040698264 cites W2059038547 @default.
- W2040698264 cites W2063242388 @default.
- W2040698264 cites W2072843628 @default.
- W2040698264 cites W2073390875 @default.
- W2040698264 cites W2078719403 @default.
- W2040698264 cites W2084472499 @default.
- W2040698264 cites W2092576233 @default.
- W2040698264 cites W2092975024 @default.
- W2040698264 cites W2099428943 @default.
- W2040698264 cites W2101335960 @default.
- W2040698264 cites W2148446741 @default.
- W2040698264 cites W2157317055 @default.
- W2040698264 cites W2169169990 @default.
- W2040698264 cites W3026281667 @default.
- W2040698264 cites W3098293149 @default.
- W2040698264 cites W3100906650 @default.
- W2040698264 cites W3101512195 @default.
- W2040698264 cites W3101978127 @default.
- W2040698264 cites W3105539019 @default.
- W2040698264 cites W3148015666 @default.
- W2040698264 cites W4229934221 @default.
- W2040698264 doi "https://doi.org/10.1086/321530" @default.
- W2040698264 hasPublicationYear "2001" @default.
- W2040698264 type Work @default.
- W2040698264 sameAs 2040698264 @default.
- W2040698264 citedByCount "23" @default.
- W2040698264 countsByYear W20406982642012 @default.
- W2040698264 countsByYear W20406982642022 @default.
- W2040698264 countsByYear W20406982642023 @default.
- W2040698264 crossrefType "journal-article" @default.
- W2040698264 hasAuthorship W2040698264A5002705012 @default.
- W2040698264 hasAuthorship W2040698264A5026031896 @default.
- W2040698264 hasAuthorship W2040698264A5039428199 @default.
- W2040698264 hasAuthorship W2040698264A5044482994 @default.
- W2040698264 hasAuthorship W2040698264A5047273464 @default.
- W2040698264 hasAuthorship W2040698264A5051825718 @default.
- W2040698264 hasAuthorship W2040698264A5062576211 @default.
- W2040698264 hasAuthorship W2040698264A5064367137 @default.
- W2040698264 hasAuthorship W2040698264A5072745684 @default.
- W2040698264 hasAuthorship W2040698264A5082342035 @default.
- W2040698264 hasAuthorship W2040698264A5089596748 @default.
- W2040698264 hasAuthorship W2040698264A5091245996 @default.
- W2040698264 hasBestOaLocation W20406982642 @default.
- W2040698264 hasConcept C118552586 @default.
- W2040698264 hasConcept C121332964 @default.
- W2040698264 hasConcept C1276947 @default.
- W2040698264 hasConcept C2780723820 @default.
- W2040698264 hasConcept C43481613 @default.
- W2040698264 hasConcept C44870925 @default.
- W2040698264 hasConcept C71924100 @default.
- W2040698264 hasConcept C98444146 @default.
- W2040698264 hasConceptScore W2040698264C118552586 @default.
- W2040698264 hasConceptScore W2040698264C121332964 @default.
- W2040698264 hasConceptScore W2040698264C1276947 @default.
- W2040698264 hasConceptScore W2040698264C2780723820 @default.
- W2040698264 hasConceptScore W2040698264C43481613 @default.
- W2040698264 hasConceptScore W2040698264C44870925 @default.
- W2040698264 hasConceptScore W2040698264C71924100 @default.
- W2040698264 hasConceptScore W2040698264C98444146 @default.
- W2040698264 hasIssue "1" @default.
- W2040698264 hasLocation W20406982641 @default.
- W2040698264 hasLocation W20406982642 @default.