2,148 research outputs found
Optical and X-ray Properties of the Swift BAT-detected AGN
The Swift Gamma-Ray Burst satellite has detected a largely unbiased towards
absorption sample of local () AGN, based solely on their
14--195 keV flux. In the first 9 months of the survey, 153 AGN sources were
detected. The X-ray properties in the 0.3--10 keV band have been compiled and
presented based on analyses with XMM-Newton, Chandra, Suzaku, and the Swift XRT
(Winter et al. 2009). Additionally, we have compiled a sub-sample of sources
with medium resolution optical ground-based spectra from the SDSS or our own
observations at KPNO. In this sample of 60 sources, we have classified the
sources using standard emission line diagnostic plots, obtained masses for the
broad line sources through measurement of the broad H emission line, and
measured the [OIII] 5007\AA luminosity of this sample. Based on continuum fits
to the intrinsic absorption features, we have obtained clues about the stellar
populations of the host galaxies. We now present the highlights of our X-ray
and optical studies of this unique sample of local AGNs, including a comparison
of the 2--10 keV and 14--195 keV X-ray luminosities with the [OIII] 5007\AA
luminosity and the implications of our results towards measurements of
bolometric luminosities.Comment: 4 pages, 2 figures, to appear in proceedings for 'X-ray Astronomy
2009', Bologna 09/2009, AIP Conference Series, Eds. A. Comastri, M. Cappi, L.
Angelin
Design and Development of the Clementine Spacecraft Sensor Bench
The Clementine spacecraft was developed to demonstrate the performance of BMDO\u27s lightweight sensor suite. The suite consisted of five different sensors (Star Trackers, UV/Vis, HiRes, NIR, LWIR) and a UDAR (Laser Impulse Detection And Ranging) system. The worst-case sensor operating requirements for the Clementine mission were: interface temperature with -20 to 2° C, alignment to +/- 100”Rad, and jitter kept below 40 Rad in 40msec. The average hear dissipation of the suite was over 100 Watts while operating for two of the five hour lunar orbit. To accomplish the mission the sensor suite was integrated onto a single-substrate sensor bench within the spacecraft. The bench met the stringent thermal, alignment, and jitter requirements of the sensors, and concurrently isolated the sensors from outside spacecraft contamination, as well as thermal and structural flexure. Also taken into account were the mission design drivers of hot thermal environment in lunar orbit, limited volume in the spacecraft, minimal weight, limited budget, and a six month schedule from concept to delivery of a flight bench. The design and development of the sensor bench will be discussed. Three different types of heat pipes were used to transport the heat of the sensors to radiators located on the side of the spacecraft. A beryllium metal block was used as a thermal capacitor during peak heat loads. Thermal straps connected sensors to heat pipes to keep thermal gradients as little as 3° C per inch across the interface. The bench was fastened in a quasi-kinematic fashion to eliminate the transfer of spacecraft structural loads and thermal flexing, and yet was rigid enough to keep alignment through launch. The bench substrate itself was made out of aluminum honeycomb. The alignment mechanism consisted of a nut-on-nut method to attain and keep the 100”Rad requirement. Volume and alignment constraints dictated sensor location on the bench. Development of the bench involved rigorous testing to insure requirements were met. These tests involved development alignment checks, vibration testing at the sensor bench level, system level qual vibes and TDVT, system level jitter testing, as well as the flight system vibe, TV AC and functional. Lessons learned will be discussed
[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
A Hard Look at NGC 5347: Revealing a Nearby Compton-thick AGN
Current measurements show that the observed fraction of Compton-thick (CT) active galactic nuclei (AGN) is smaller than the expected values needed to explain the cosmic X-ray background. Prior fits to the X-ray spectrum of the nearby Seyfert-2 galaxy NGC 5347 (z = 0.00792, D = 35.5 Mpc ) have alternately suggested a CT and Compton-thin source. Combining archival data from Suzaku, Chandra, andâmost importantlyânew data from NuSTAR, ... See full text for complete abstrac
XMM Follow-Up Observations of Three Swift BAT-Selected Active Galactic Nuclei
We present XMM-Newton observations of three AGN taken as part of a hunt to
find very heavily obscured Compton-thick AGN. For obscuring columns greater
than 10^25 cm^-2, AGN are only visible at energies below 10 keV via
reflected/scattered radiation, characterized by a flat power-law. We therefore
selected three objects (ESO 417-G006, IRAS 05218-1212, and MCG -01-05-047) from
the Swift BAT hard X-ray survey catalog with Swift X-ray Telescope XRT 0.5-10
keV spectra with flat power-law indices as candidate Compton-thick sources for
follow-up observations with the more sensitive instruments on XMM-Newton. The
XMM spectra, however, rule out reflection-dominated models based on the
weakness of the observed Fe K-alpha lines. Instead, the spectra are well-fit by
a model of a power-law continuum obscured by a Compton-thin absorber, plus a
soft excess. This result is consistent with previous follow-up observations of
two other flat-spectrum BAT-detected AGN. Thus, out of the six AGN in the
22-month BAT catalog with apparently flat Swift XRT spectra, all five that have
had follow-up observations are not likely Compton-thick. We also present new
optical spectra of two of these objects, IRAS 05218-1212 and MCG -01-05-047.
Interestingly, though both these AGN have similar X-ray spectra, their optical
spectra are completely different, adding evidence against the simplest form of
the geometric unified model of AGN. IRAS 05218-1212 appears in the optical as a
Seyfert 1, despite the ~8.5x10^22 cm^-2 line-of-sight absorbing column
indicated by its X-ray spectrum. MCG -01-05-047's optical spectrum shows no
sign of AGN activity; it appears as a normal galaxy.Comment: 18 pages including 4 figures, accepted by 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; clientâs self-positioning, clientâs 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
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