1,505 research outputs found
[O III] and X-ray Properties of a Complete Sample of Hard X-ray Selected AGNs in the Local Universe
We study the correlation between the [O III] and X-ray
luminosities of local Active Galactic Nuclei (AGNs), using a complete, hard
X-ray ( keV) selected sample in the Swift/BAT 9-month catalog. From our
optical spectroscopic observations at the South African Astronomical
Observatory and the literature, a catalog of [O III] line flux
for all 103 AGNs at Galactic latitudes of is complied.
Significant correlations with intrinsic X-ray luminosity () are
found both for observed () and extinction-corrected () luminosities, separately for X-ray unabsorbed and absorbed
AGNs. We obtain the regression form of and from the whole sample. The absorbed AGNs with low
(0.5\%) scattering fractions in soft X-rays show on average smaller and ratios than the
other absorbed AGNs, while those in edge-on host galaxies do not. These results
suggest that a significant fraction of this population are buried in tori with
small opening angles. By using these vs.
correlations, the X-ray luminosity function of local AGNs (including Compton
thick AGNs) in a standard population synthesis model gives much better
agreement with the [O III] luminosity function derived from the
Sloan Digital Sky Survey than previously reported. This confirms that hard
X-ray observations are a very powerful tool to find AGNs with high
completeness.Comment: 14 pages including 11 figures and 3 tables, accepted for publication
in ApJ. In this manuscript, the observed 14-195 keV luminosities in Table 1
have been corrected to be exactly the same as in the original Swift/BAT
9-month catalog. Accordingly, Figures 2(a) and 3(a) and a part of Tables 2
and 3 have been updated. The changes from the previous version are small and
do not affect the tex
The relationship between adverse childhood experiences, coping using sex, and adult sexual coercion in non-incarcerated, community-based females
Adverse childhood experiences have been associated with negative outcomes in adulthood, including sexual offending. Using a cross-sectional design, we investigated whether self-reported adverse childhood experiences related to the perpetration of coercive sexual acts among 250 females recruited from the community. Furthermore, we examined whether sexualised coping mediated any potential relationship between childhood experiences and sexual coercion. A Spearman’s rank order correlation revealed no relationship between adverse childhood experiences and sexual coercion. However, adverse childhood experiences were significantly correlated with sexualised coping, which in turn was correlated with sexual coercion. Additionally, there was a significant but small indirect effect of adverse childhood experiences on sexual coercion through sexualised coping. Findings may help researchers to better understand the causal relationship between childhood experiences, sexual coping, and sexual coercion in females
Investigating the evolution of the dual AGN system ESO~509-IG066
We analyze the evolution of the dual AGN in ESO 509-IG066, a galaxy pair
located at z=0.034 whose nuclei are separated by 11 kpc. Previous observations
with XMM-Newton on this dual AGN found evidence for two moderately obscured
( cm) X-ray luminous ( erg/s) nuclear
sources. We present an analysis of subsequent Chandra, NuSTAR and Swift/XRT
observations that show one source has dropped in flux by a factor of 10 between
2004 and 2011, which could be explained by either an increase in the absorbing
column or an intrinsic fading of the central engine possibly due to a decrease
in mass accretion. Both of these scenarios are predicted by galaxy merger
simulations. The source which has dropped in flux is not detected by NuSTAR,
which argues against absorption, unless it is extreme. However, new Keck/LRIS
optical spectroscopy reveals a previously unreported broad H-alpha line which
is highly unlikely to be visible under the extreme absorption scenario. We
therefore conclude that the black hole in this nucleus has undergone a dramatic
drop in accretion rate. From AO-assisted near-infrared integral-field
spectroscopy of the other nucleus, we find evidence that the galaxy merger is
having a direct effect on the kinematics of the gas close to the nucleus of the
galaxy, providing a direct observational link between the galaxy merger and the
mass accretion rate on to the black hole.Comment: Accepted for publication in Ap
X-ray bolometric corrections for Compton-thick active galactic nuclei
We present X-ray bolometric correction factors, (), for Compton-thick (CT) active galactic nuclei (AGN) with the aim
of testing AGN torus models, probing orientation effects, and estimating the
bolometric output of the most obscured AGN. We adopt bolometric luminosities,
, from literature infrared (IR) torus modeling and compile published
intrinsic 2--10 keV X-ray luminosities, , from X-ray torus modeling of
NuSTAR data. Our sample consists of 10 local CT AGN where both of these
estimates are available. We test for systematic differences in
values produced when using two widely used IR torus models and two widely used
X-ray torus models, finding consistency within the uncertainties. We find that
the mean of our sample in the range
erg/s is log
with an intrinsic scatter of dex, and that our derived
values are consistent with previously established relationships between
and and and Eddington ratio. We
investigate if is dependent on by comparing our results on
CT AGN to published results on less-obscured AGN, finding no significant
dependence. Since many of our sample are megamaser AGN, known to be viewed
edge-on, and furthermore under the assumptions of AGN unification whereby
unobscured AGN are viewed face-on, our result implies that the X-ray emitting
corona is not strongly anisotropic. Finally, we present values
for CT AGN identified in X-ray surveys as a function of their observed ,
where an estimate of their intrinsic is not available, and redshift,
useful for estimating the bolometric output of the most obscured AGN across
cosmic time.Comment: Accepted for publication in Ap
Interactional positioning and narrative self-construction in the first session of psychodynamic-interpersonal psychotherapy
The purpose of this study is to identify possible session one indicators of end of treatment psychotherapy outcome using the framework of three types of interactional positioning; client’s self-positioning, client’s positioning between narrated self and different partners, and the positioning between client and therapist. Three successful cases of 8-session psychodynamic-interpersonal (PI) therapy were selected on the basis of client Beck Depression Inventory scores. One unsuccessful case was also selected against which identified patterns could be tested. The successful clients were more descriptive about their problems and demonstrated active rapport-building, while the therapist used positionings expressed by the client in order to explore the positionings developed between them during therapy. The unsuccessful case was characterized by lack of positive self-comment, minimization of agentic self-capacity, and empathy-disrupting narrative confusions. We conclude that the theory of interactional positioning has been useful in identifying patterns worth exploring as early indicators of success in PI therapy
IC 751: a new changing-look AGN discovered by NuSTAR
We present the results of five NuSTAR observations of the type 2 active
galactic nucleus (AGN) in IC 751, three of which were performed simultaneously
with XMM-Newton or Swift/XRT. We find that the nuclear X-ray source underwent a
clear transition from a Compton-thick () to a Compton-thin () state on timescales of months, which makes
IC 751 the first changing-look AGN discovered by NuSTAR. Changes of the
line-of-sight column density at a level are also found on a
time-scale of hours ().
From the lack of spectral variability on timescales of ks we infer
that the varying absorber is located beyond the emission-weighted average
radius of the broad-line region, and could therefore be related either to the
external part of the broad-line region or a clumpy molecular torus. By adopting
a physical torus X-ray spectral model, we are able to disentangle the column
density of the non-varying absorber () from that of the varying clouds
[], and to constrain that of
the material responsible for the reprocessed X-ray radiation (). We find evidence of significant intrinsic X-ray
variability, with the flux varying by a factor of five on timescales of a few
months in the 2-10 and 10-50 keV band.Comment: Accepted for publication in ApJ, 11 pages, 6 figure
Broadband Observations of the Compton-thick Nucleus of NGC 3393
We present new NuSTAR and Chandra observations of NGC 3393, a galaxy reported
to host the smallest separation dual AGN resolved in the X-rays. While past
results suggested a 150 pc separation dual AGN, three times deeper Chandra
imaging, combined with adaptive optics and radio imaging suggest a single,
heavily obscured, radio-bright AGN. Using VLA and VLBA data, we find an AGN
with a two-sided jet rather than a dual AGN and that the hard X-ray, UV,
optical, NIR, and radio emission are all from a single point source with a
radius <0.2". We find that the previously reported dual AGN is most likely a
spurious detection resulting from the low number of X-ray counts (<160) at 6-7
keV and Gaussian smoothing of the data on scales much smaller than the PSF
(0.25" vs. 0.80" FWHM). We show that statistical noise in a single Chandra PSF
generates spurious dual peaks of the same separation (0.550.07" vs. 0.6")
and flux ratio (399% vs. 32% of counts) as the purported dual AGN. With
NuSTAR, we measure a Compton-thick source (NH=
cm) with a large torus half-opening angle, {\theta}=79 which we
postulate results from feedback from strong radio jets. This AGN shows a 2-10
keV intrinsic to observed flux ratio of 150. Using simulations, we find that
even the deepest Chandra observations would severely underestimate the
intrinsic luminosity of NGC 3393 above z>0.2, but would detect an unobscured
AGN of this luminosity out to high redshift (z=5).Comment: Accepted for publication in ApJ. 15 Figures and 4 table
Broadband X-ray spectral analysis of the Seyfert 1 galaxy GRS 1734-292
We discuss the broadband X-ray spectrum of GRS 1734-292 obtained from
non-simultaneous XMM-Newton and NuSTAR observations, performed in 2009 and
2014, respectively. GRS1734-292 is a Seyfert 1 galaxy, located near the
Galactic plane at . The NuSTAR spectrum ( keV) is dominated by
a primary power-law continuum with and a high-energy
cutoff keV, one of the lowest measured by NuSTAR in a
Seyfert galaxy. Comptonization models show a temperature of the coronal plasma
of keV and an optical depth, assuming a slab
geometry, or a similar temperature and
assuming a spherical geometry. The 2009 XMM-Newton
spectrum is well described by a flatter intrinsic continuum
() and one absorption line due to Fe\textsc{XXV}
K produced by a warm absorber. Both data sets show a modest iron
K emission line at keV and the associated Compton reflection, due
to reprocessing from neutral circumnuclear material
X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission
We present results on the X-ray and optical/UV emission from the type IIP SN
2006bp and the interaction of the SN shock with its environment, obtained with
the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on-board the Swift
observatory. SN 2006bp is detected in X-rays at a 4.5 sigma level of
significance in the merged XRT data from days 1 to 12 after the explosion. If
the X-ray luminosity of (1.8+/-0.4)E39 ergs/s is caused by interaction of the
SN shock with circumstellar material (CSM), deposited by a stellar wind from
the progenitor's companion star, a mass-loss rate of ~E-05 M_sun/yr is
inferred. The mass-loss rate is consistent with the non-detection in the radio
with the VLA on days 2, 9, and 11 after the explosion and characteristic of a
red supergiant progenitor with a mass around 12-15 M_sun prior to the
explosion. In combination with a follow-up XMM-Newton observation obtained on
day 21 after the explosion, an X-ray rate of decline with index 1.2+/-0.6 is
inferred. Since no other SN has been detected in X-rays prior to the optical
peak and since type IIP SNe have an extended 'plateau' phase in the optical, we
discuss the scenario that the X-rays might be due to inverse Compton scattering
of photospheric optical photons off relativistic electrons produced in
circumstellar shocks. However, due to the high required value of the Lorentz
factor (~10-100) we conclude that Inverse Compton scattering is an unlikely
explanation for the observed X-ray emission. The fast evolution of the
optical/ultraviolet spectral energy distribution and the spectral changes
observed with Swift reveal the onset of metal line-blanketing and cooling of
the expanding photosphere during the first few weeks after the outburst.Comment: 8 pages, 5 figures, accepted for publication in Ap
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