scholarly journals The Half Million Quasars (HMQ) Catalogue

2015 ◽  
Vol 32 ◽  
Author(s):  
Eric W. Flesch
Keyword(s):  
High Confidence ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac

AbstractA quasar catalogue is presented with a total of 510 764 objects including 424 748 type 1 QSOs and 26 623 type 1 AGN complete from the literature to 2015 January 25. Also included are 25015 high-confidence SDSS-based photometric quasars with radio/X-ray associations, 1595 BL Lac objects, and 32783 type 2 objects. Each object is displayed with arcsecond-accurate astrometry, red and blue photometry, redshift, citations, and radio and X-ray associations where present. Also, 114 new spectroscopically confirmed quasars are presented.

scholarly journals A Comparison of the X-ray Spectra of Quasars and BL Lac Objects

1989 ◽  
Vol 134 ◽  
pp. 197-198
Author(s):  
D. M. Worrall ◽  
B. J. Wilkes
Keyword(s):  
Power Law ◽  
Radio Spectrum ◽  
Spectral Indices ◽  
Mean Power ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac ◽  
Infrared Frequencies

Quasars with similar core-compact radio properties can be classified by their differences at optical and infrared frequencies. Their X-ray properties might be expected to be similar if the synchrotron self-Compton mechanism relates their radio and X-ray emission. We have compared the 0.2–3.5 keV mean power-law energy spectral indices, , for 4 quasar classes: 12 Highly Polarized QSOs (HPQs), 19 Flat Radio Spectrum, core-compact, low-polarization, QSOs (FRS QSOs), 24 radio-selected BL Lac objects, and 7 X-ray-selected BL Lac objects.

AGN1 vs AGN2 dichotomy as seen from the point of view of ionized outflows

2019 ◽  
Vol 15 (S356) ◽  
pp. 96-96
Author(s):  
Eleonora Sani
Keyword(s):  
Accretion Rate ◽  
Point Of View ◽  
Emission Lines ◽  
Black Hole Mass ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Wide Range ◽  
Strong Contrast

AbstractI present a detailed study of ionized outflows in a large sample of 650 hard X-ray detected AGN. Taking advantage of the legacy value of the BAT AGN Spectroscopic Survey (BASS, DR1), we are able to reveal the faintest wings of the [OIII] emission lines associated with outflows. The sample allows us to derive the incidence of outflows covering a wide range of AGN bolometric luminosity and test how the outflow parameters are related with various AGN power tracers, such as black hole mass, Eddington ratio, luminosity. I’ll show how ionized outflows are more frequently found in type 1.9 and type 1 AGN (50% and 40%) with respect to the low fraction in type 2 AGN (20%). Within such a framework, I’ll demonstrate how type 2 AGN outflows are almost evenly balanced between blue- and red-shifted winds. This, in strong contrast with type 1 and type 1.9 AGN outflows which are almost exclusively blue-shifted. Finally, I’ll prove how the outflow occurrence is driven by the accretion rate, whereas the dependence of outflow properties with respect to the other AGN power tracers happens to be quite mild.

scholarly journals A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs with AKARI

2013 ◽  
Vol 9 (S304) ◽  
pp. 66-67
Author(s):  
A. Castro ◽  
T. Miyaji ◽  
M. Shirahata ◽  
S. Oyabu ◽  
D. Clark ◽  
...  
Keyword(s):  
Star Formation ◽  
Neutral Hydrogen ◽  
Infrared Camera ◽  
X Ray ◽  
Star Formation Activity ◽  
Hydrogen Column Density ◽  
Polycyclic Aromatic ◽  
Low X

AbstractWe explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L14-195keV versus log L3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L14-195keV/MBH) versus log (L3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.

scholarly journals There is a Correlation between Fragility Fractures of the Pelvis and a Circle-Type Morphology of the True Pelvis, but Not with Pelvic Incidence

2021 ◽  
pp. 1-6
Author(s):  
Matthias Spalteholz ◽  
Matthias Spalteholz ◽  
Gulow Jens ◽  
Pap Geza
Keyword(s):  
Pelvic Incidence ◽  
Fragility Fractures ◽  
Statistical Correlation ◽  
X Ray ◽  
Lack Of Information ◽  
The Mean ◽  
Fracture Types ◽  
Type 3

Purpose: Osteoporosis is a major risk factor for the development of fragility fractures of the pelvis (FFP). There is a lack of information about the influence of anatomical conditions such as Pelvic Incidence and Pelvic Ratio (DT/DS ratio) on this kind of fractures. Methods: This is a monocentric retrospective analysis. X-ray images of the lumbar spine and pelvis and 3D-MPR CT reconstructions of the pelvis were analysed to determine Pelvic Incidence (PI) and Pelvic Ratio (PR) in 141 fragility fractures of the pelvis. Statistical analyses were performed to examine the correlation between these spinopelvic parameters and fragility fractures of the pelvis. Results: A total of 141 fragility fractures of the pelvis (14 men = 9.93%, 127 women = 90.07%) were analysed. According to the FFP-classification we recognized FFP type 1 fractures in 19.15%, FFP type 2 in 41.13%, FFP type 3 in 8.51% and FFP type 4 fractures in 32.21%. The mean PI was 58.83º. There was no statistical correlation between PI and fracture types (p=0.81). The mean PR was 1.099. 57 patients (40.43%) demonstrated a DT/DS ratio ≤ 1.06, corresponding to a circle-type morphology. 24 patients (17.02%) demonstrated a DT/DS ratio ≥ 1.18, corresponding to an ellipse-type pelvis. A circle-type pelvis is significantly more often associated with fragility fractures of the pelvis than an ellipse-type morphology (p<0.001). Conclusion: The results of our work demonstrate a strong statistical correlation between the circle-type morphology of the pelvis (PR ≤ 1.06) and fragility fractures of the pelvis. There is no statistical correlation between fragility fractures of the pelvis and Pelvic Incidence.

BL Lac objects as X-Ray sources: The Exosat observations

2005 ◽  
pp. 281-289 ◽  
Author(s):  
D. Maccagni ◽  
B. Garilli ◽  
P. Barr ◽  
P. Giommi ◽  
A. Pollock
Keyword(s):  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac

X-Ray Emission from BL Lac Objects: Comparison to the Synchrotron Self-Compton Models

1982 ◽  
pp. 383-384
Author(s):  
Daniel A. Schwartz ◽  
Greg Madejski ◽  
William H.-M. Ku
Keyword(s):  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac

A Comparison of the X-Ray Spectra of Quasars and BL Lac Objects

1989 ◽  
pp. 197-198
Author(s):  
D. M. Worrall ◽  
B. J. Wilkes
Keyword(s):  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac

scholarly journals Optical Short-Term Variability in the X-Ray-Selected BL Lac Object IE 0317+186 and the Radio-Selected BL Lac Object ON231

1989 ◽  
Vol 134 ◽  
pp. 108-109
Author(s):  
F.Z. Cheng ◽  
J.F. Lu ◽  
G.Z. Xie ◽  
K.H. Li ◽  
Z.L. Li ◽  
...  
Keyword(s):  
Light Curves ◽  
Optical Monitoring ◽  
National Observatory ◽  
Image System ◽  
Short Term ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac ◽  
Ccd Image ◽  
Short Term Variability

In order to compare X-ray-selected BL Lac objects with radio-selected BL Lac objects, we have carried out optical monitoring of some of these objects for about three years at Yunnan Observatory in China. All observations have been made with a CCD-image system at the f/13.3 Cassegrain focus of the 102-cm RCC telescope. The CCD-image system was developed by Ye et al. in Kitt Peak National Observatory of USA (Ye et al., 1985). The filters used were as follows: B-GG385(2mm)+BG12(1mm)+BG18(1mm), V-GG495(2mm)+BG18(2mm). After observing many times, more complete light curves have obtained for the X-ray-selected BL Lac object IE 0317+186 and the radio-selected BL Lac object ON 231, respectively(Fig 1 and Fig 2). Fig 1 shows that IE 0317+186 has a characteristic timescale of about 4.5hours with an amplitudes of ΔV≃0.65 mag. Fig 2 indicates that a timescale of short-term variability in ON 231 is about 70 min with an amplitudes of ΔB≃0.8 mag.

scholarly journals Discovery of Five New X-ray–Selected BL Lacertae Objects and Three New Quasars

1997 ◽  
Vol 159 ◽  
pp. 423-424
Author(s):  
G.Z. Xie ◽  
W. Brinkmann ◽  
G.W. Cha ◽  
S. Laurent-Muehleisen ◽  
Y.H. Zhang ◽  
...  
Keyword(s):  
Astronomical Observatory ◽  
Bl Lacertae Objects ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lacertae ◽  
Bl Lac

Through combined ROSAT and VLA observations, we have identified 19 BL Lac/quasar candidates. In 1994 December, 1995 January and October, and 1996 January 1996, we obtained spectra of all 19 candidates using the 2.16-m telescope of Beijing Astronomical Observatory. The dispersion used is 195 Å mm−1, which yields a dispersion of about 4.65 Å pixel−1, and the wavelength coverage is 3500–7800 Å. Five of these objects are uniformly featureless, and we identify them as BL Lac objects. Three new quasars are also identified. Table 1 presents VLA positions and redshifts for the 5 new BL Lac objects and three new quasars. By checking them in the NASA/IPAC Extragalactic Database (NED) and Véron-Cetty & Véron’s (1993) Catalogue of Quasars and AGNs, and other recent reports about discovery of new BL Lac objects and quasars, we find that these sources are previously unreported.

scholarly journals X-Ray Surveys as Tools to Investigate the Cosmological Evolution of Quasars, BL Lac Objects and Clusters of Galaxies

1987 ◽  
Vol 124 ◽  
pp. 593-595
Author(s):  
Isabella M. Gioia ◽  
Tommaso Maccacaro ◽  
Anna Wolter
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Progress Report ◽  
Cosmological Evolution ◽  
Clusters Of Galaxies ◽  
Bl Lac Objects ◽  
X Ray ◽  
Basic Properties ◽  
Bl Lac ◽  
Einstein Observatory

We present a progress report on a major extension of the Einstein Observatory Medium Sensitivity Survey (MSS). The basic properties of the extragalactic sources identified with Active Galactic Nuclei (AGN) and clusters of galaxies are discussed. Results from previous work are briefly summarized.

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