Search

Start Over Validation Level 2
25161. X-ray_peak-BCG offset for PSZ1 clusters
ID:
ivo://CDS.VizieR/J/MNRAS/457/4515
Title:
X-ray_peak-BCG offset for PSZ1 clusters
Short Name:
J/MNRAS/457/4515
Date:
21 Oct 2021
Publisher:
CDS
Description:
We want to characterize the dynamical state of galaxy clusters detected with the Sunyaev-Zeldovich (SZ) effect by Planck and compare them with the dynamical state of clusters selected in X-rays survey. We analysed a representative subsample of the Planck SZ catalogue, containing the 132 clusters with the highest signal to noise ratio and characterize their dynamical state using as an indicator the projected offset between the peak of the X-ray emission and the position of the Brightest cluster galaxy. We compare the distribution of this indicator for the Planck SZ-selected sample and three X-ray-selected samples (HIFLUGCS, MACS and REXCESS). The distributions are significantly different and the fraction of relaxed objects is smaller in the Planck sample (52+/-4 per cent) than in X-ray samples (~=74 per cent) We interpret this result as an indication of different selection effects affecting X-rays (e.g. 'cool core bias') and SZ surveys of galaxy clusters.
25162. X-ray point sources near the Galactic Center
ID:
ivo://CDS.VizieR/J/ApJ/706/223
Title:
X-ray point sources near the Galactic Center
Short Name:
J/ApJ/706/223
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the log N-logS and spatial distributions of X-ray point sources in seven Galactic bulge (GB) fields within 4{deg} from the Galactic center (GC). We compare the properties of 1159 X-ray point sources discovered in our deep (100ks) Chandra observations of three low extinction Window fields near the GC with the X-ray sources in the other GB fields centered around Sgr B2, Sgr C, the Arches Cluster, and Sgr A* using Chandra archival data. To reduce the systematic errors induced by the uncertain X-ray spectra of the sources coupled with field-and-distance-dependent extinction, we classify the X-ray sources using quantile analysis and estimate their fluxes accordingly. We also compare the total X-ray and infrared surface brightness using the Chandra and Spitzer observations of the regions. GB X-ray sources can be of the same or similar type. Their X-ray luminosity and spectral properties support the idea that the most likely candidate is magnetic cataclysmic variables (CVs), primarily intermediate polars (IPs).
25163. X-ray polarization predictions in blazars
ID:
ivo://CDS.VizieR/J/ApJ/880/29
Title:
X-ray polarization predictions in blazars
Short Name:
J/ApJ/880/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray polarization should provide new probes of magnetic field geometry and acceleration physics near the base of blazar jets, but near-future missions will have limited sensitivity. We thus use existing lower energy data and X-ray variability measurements in the context of a basic synchro-Compton model to predict the X-ray polarization level and the probability of detection success for individual sources, listing the most attractive candidates for an Imaging X-ray Polarimetry Explorer campaign. We find that, as expected, several high-peak blazars such as Mrk 421 can be easily measured in 100ks exposures. Most low-peak sources should only be accessible to triggered campaigns during bright flares. Surprisingly, a few intermediate peak sources can have anomalously high X-ray polarization and thus are attractive targets.
25164. X-ray power spectra of Cygnus X-1
ID:
ivo://CDS.VizieR/J/A+A/407/1039
Title:
X-ray power spectra of Cygnus X-1
Short Name:
J/A+A/407/1039
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the long term evolution of the timing properties of the black hole candidate Cygnus X-1 in the 0.002-128 Hz frequency range as monitored from 1998 to 2001 with the Rossi X-ray Timing Explorer (RXTE). For most of this period the source was in its hard state.
25165. X-ray properties of A,B-types, T-Tauri stars & YSOs
ID:
ivo://CDS.VizieR/J/AJ/162/153
Title:
X-ray properties of A,B-types, T-Tauri stars & YSOs
Short Name:
J/AJ/162/153
Date:
15 Mar 2022
Publisher:
CDS
Description:
We use X-ray and infrared observations to study the properties of three classes of young stars in the Carina Nebula: intermediate-mass (2-5M{sun}) pre-main-sequence stars (IMPS; i.e., intermediate-mass T Tauri stars), late-B and A stars on the zero-age main sequence (AB), and lower-mass T Tauri stars (TTS). We divide our sources among these three subclassifications and further identify disk-bearing young stellar objects versus diskless sources with no detectable infrared (IR) excess emission using IR (1-8{mu}m) spectral energy distribution modeling. We then perform X-ray spectral fitting to determine the hydrogen-absorbing column density (N_H_), absorption-corrected X-ray luminosity (L_X_), and coronal plasma temperature (kT) for each source. We find that the X-ray spectra of both IMPS and TTS are characterized by similar kT and N_H_, and on average L_X_/L_bol_~4x10^-4^. IMPS are systematically more luminous in X-rays (by ~0.3dex) than all other subclassifications, with median L_X_=2.5x10^31^erg/s, while AB stars of similar masses have X-ray emission consistent with TTS companions. These lines of evidence converge on a magnetocoronal flaring source for IMPS X-ray emission, a scaled-up version of the TTS emission mechanism. IMPS therefore provide powerful probes of isochronal ages for the first ~10Myr in the evolution of a massive stellar population, because their intrinsic, coronal X-ray emission decays rapidly after they commence evolving along radiative tracks. We suggest that the most luminous (in both X-rays and IR) IMPS could be used to place empirical constraints on the location of the intermediate-mass stellar birth line.
25166. X-ray properties of AGN
ID:
ivo://CDS.VizieR/J/A+A/309/81
Title:
X-ray properties of AGN
Short Name:
J/A+A/309/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
ROSAT spectra of 86 Active Galactic Nuclei (AGN) with a broad range of optical FeII strengths have been analyzed. The results of the spectral analysis have been combined with optical and radio data as well as with optical emission line properties collected from the literature to understand the origin of the strong FeII emission and the nature of the soft X-ray excess.
25167. X-ray properties of AGN from the CJF sample
ID:
ivo://CDS.VizieR/J/A+A/476/759
Title:
X-ray properties of AGN from the CJF sample
Short Name:
J/A+A/476/759
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the soft X-ray properties obtained in the ROSAT All-Sky survey and from pointed PSPC observations for the AGN in the complete flux-density limited Caltech-Jodrell Bank flat spectrum sample (hereafter CJF). CJF is a VLBI survey (VLBA observations at 5GHz) of 293 AGN with detailed information on jet component motion. We investigate and discuss the soft X-ray properties of this AGN sample and examine the correlations between X-ray and VLBI properties, test beaming scenarios, and search for the discriminating properties between the sub-samples detected and not detected by ROSAT. Comparing the observed and the predicted X-ray fluxes by assuming an Inverse Compton (IC) origin for the observed X-rays, we compute the beaming or Doppler factor, {delta}_IC_, for the CJF sources and compare it with the equipartition Doppler factor, {delta}_EQ_. We further contrast the Doppler factors with other beaming indicators derived from the VLBI observations, such as the value of the expansion velocity, and the observed and intrinsic brightness temperature. We calculate two different core dominance parameters (R): the ratio of total VLBI flux to single-dish flux, R_V_, and the ratio of the VLBI core-component flux to single-dish flux, R_C_. In addition, we investigate the large-scale radio structure of the AGN and the difference between the pc- and kpc-scale structure (misalignment) with regard to the X-ray observations.
25168. X-ray properties of AGN in CDFS
ID:
ivo://CDS.VizieR/J/A+A/451/457
Title:
X-ray properties of AGN in CDFS
Short Name:
J/A+A/451/457
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS, J/ApJS/139/369) taking advantage of optical spectroscopy and photometric redshifts for 321 extragalactic sources out of the total sample of 347 sources. As a default spectral model, we adopt a power law with slope Gamma with an intrinsic redshifted absorption N_H_, a fixed Galactic absorption and an unresolved Fe emission line. For 82 X-ray bright sources, we are able to perform the X-ray spectral analysis leaving both Gamma and N_H_ free.
25169. X-ray properties of AGNs in XBS
ID:
ivo://CDS.VizieR/J/A+A/530/A42
Title:
X-ray properties of AGNs in XBS
Short Name:
J/A+A/530/A42
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray surveys are a key instrument in the study of active galactic nuclei (AGN). Thanks to their penetrating ability, X-rays are able to map the innermost regions close to the central super massive black hole (SMBH) as well as to detect and characterize its emission up to high redshift. We present here a detailed X-ray spectral analysis of the AGN belonging to the XMM-Newton bright survey (XBS). The XBS is composed of two flux-limited samples selected in the complementary 0.5-4.5 and 4.5-7.5keV energy bands and comprising more than 300 AGN up to redshift ~2.4. We performed an X-ray analysis following two different approaches: by analyzing individually each AGN X-ray spectrum and by constructing average spectra for different AGN types.
25170. X-ray properties of ASCA objects
ID:
ivo://CDS.VizieR/J/PASJ/56/965
Title:
X-ray properties of ASCA objects
Short Name:
J/PASJ/56/965
Date:
21 Oct 2021
Publisher:
CDS
Description:
Utilizing ASCA archival data of about 300 objects of elliptical galaxies, groups, and clusters of galaxies, we performed systematic measurements of the X-ray properties of hot gas in their systems, and compiled them in this paper. The steepness of the luminosity-temperature (LT) relation, L_X_{prop.to}(kT)^alpha^, in the range of kT~1.5-15keV is alpha=3.17+/-0.15, consistent with previous measurements.

Limit your search

more »

more »

more »

more »

more »

more »

more »

more »