Search

Start Over Capability Type Simple Cone Search
17761. X-ray emission from the Sombrero galaxy
ID:
ivo://CDS.VizieR/J/ApJ/721/1368
Title:
X-ray emission from the Sombrero galaxy
Short Name:
J/ApJ/721/1368
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200ks. With a detection limit of L_X_~10^37^erg/s and a field of view covering a galactocentric radius of ~30kpc (11.5'), 383 sources are detected. Cross-correlation with Spitler et al.'s catalog of Sombrero globular clusters (GCs) (Cat. J/AJ/132/1593) identified from HST/ACS observations reveals 41 X-ray sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-law indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC-LF at fainter luminosities down to 10^35^erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic active galactic nuclei (52+/-11 [1{sigma}]) whose surface density is constrained by deep X-ray surveys.
17762. X-ray emission from the Sombrero galaxy (NGC 4594)
ID:
ivo://CDS.VizieR/J/MNRAS/376/960
Title:
X-ray emission from the Sombrero galaxy (NGC 4594)
Short Name:
J/MNRAS/376/960
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an X-ray study of the massive edge-on Sa galaxy, Sombrero (M 104; NGC 4594), based on XMM-Newton and Chandra observations. A list of 62 XMM-Newton and 175 Chandra discrete X-ray sources is provided, the majority of which are associated with the galaxy. Spectral analysis is carried out for relatively bright individual sources and for an accumulated source spectrum.
17763. X-ray emission in cool main sequence stars
ID:
ivo://CDS.VizieR/J/A+A/410/671
Title:
X-ray emission in cool main sequence stars
Short Name:
J/A+A/410/671
Date:
21 Oct 2021
Publisher:
CDS
Description:
The maximum amplitude A_max_ of spot-induced brightness variations from long-term V-band photometry and the ratio L_X_/L_bol_ between X-ray and bolometric luminosities are suitable indicators of the level of magnetic activity in the photosphere and in the corona of late-type stars, respectively. By using these activity indicators we investigate the dependence of coronal X-ray emission on the level of photospheric starspot activity in a homogeneous sample of low mass main-sequence field and cluster stars of different ages (IC 2602, IC 4665, IC 2391, {alpha} Per, Pleiades and Hyades).
17764. X-ray emission in Orion Nebula young stars
ID:
ivo://CDS.VizieR/J/ApJS/160/450
Title:
X-ray emission in Orion Nebula young stars
Short Name:
J/ApJS/160/450
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the spatial distribution of X-ray-emitting plasma in a sample of young Orion Nebula Cluster stars by modulation of their X-ray light curves due to stellar rotation. The study, part of the Chandra Orion Ultradeep Project (COUP, Cat. <J/ApJS/160/319>), is made possible by the exceptional length of the observation: 10 days of ACIS integration during a time span of 13 days, yielding a total of 1616 detected sources in the 17'x17' field of view. We here focus on a subsample of 233 X-ray-bright stars with known rotational periods. We search for X-ray modulation using the Lomb Normalized Periodogram method.
17765. X-ray emission in the Ursa Major stream.
ID:
ivo://CDS.VizieR/J/ApJ/351/492
Title:
X-ray emission in the Ursa Major stream.
Short Name:
J/ApJ/351/492
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results are reported from a comprehensive survey of X-ray emission from stars known or suspected to be members of the UMa cluster and/or stream. Of the 42 UMa member stars surveyed, 18 were detected as X-ray sources, and spectral analysis was performed for 10 stars with sufficient X-ray counts. Consideration is given to relations between X-ray luminosity, color, and kinematics of the sample stars, and the X-ray spectra of the UMa stars are discussed in the context of the general problem of stellar X-ray temperatures. Also confirmed is the lack of X-ray-emitting A dwarfs among UMa members; among stars of later spectral type there is a rather large dispersion in X-ray luminosity. This dispersion cannot readily be explained by contamination with field star interlopers and appears rather to be a property of the UMa X-ray luminosity distribution function.
17766. X-ray emission of RASS Abell clusters
ID:
ivo://CDS.VizieR/J/AJ/126/2740
Title:
X-ray emission of RASS Abell clusters
Short Name:
J/AJ/126/2740
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of the X-ray emission for a complete sample of 288 Abell clusters spanning the redshift range 0.016<=z<=0.09 from the ROSAT All-Sky Survey. This sample is based on our 20cm VLA survey of nearby Abell clusters. We find an X-ray detection rate of 83%. We report cluster X-ray fluxes and luminosities and two different flux ratios indicative of the concentration and extent of the emission. We examine correlations between the X-ray luminosity, Abell richness, and Bautz-Morgan and Rood-Sastry cluster morphologies. We find a strong correlation between LX and cluster richness coupled with a dependence on the optical morphological type. These results are consistent with the observed scatter between X-ray luminosity and temperature and a large fraction of cooling flows. For each cluster field, we also report the positions, peak X-ray fluxes, and flux ratios of all X-ray peaks above 3{sigma} significance within a box of 2x2(h_75_)^-1^Mpc centered on Abell's position.
17767. X-ray emission of T Tau stars in Lupus 3
ID:
ivo://CDS.VizieR/J/A+A/454/595
Title:
X-ray emission of T Tau stars in Lupus 3
Short Name:
J/A+A/454/595
Date:
21 Oct 2021
Publisher:
CDS
Description:
I present analysis results of an XMM-Newton observation of the Lupus 3 region that contains a high proportion of young low mass T Tauri stars in the Lupus star-forming complex. The detection of X-ray sources in 0.5 to 4.5-keV images of the Lupus 3 core was performed using the standard source detection method of the XMM-Newton Science Analysis Software. One hundred and two candidate X-ray sources were detected in the 30-arcmin diameter field-of-view of the EPIC cameras, of which 25 have visible or near-IR counterparts that are known as pre-main sequence stars.
17768. X-ray emitters in the Groth-Westphal strip
ID:
ivo://CDS.VizieR/J/ApJ/706/810
Title:
X-ray emitters in the Groth-Westphal strip
Short Name:
J/ApJ/706/810
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820nm and 920nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200ks are analyzed and combined with optical broadband data of the Groth field, in order to study a set of optical structural parameters of the X-ray emitters and its relation with X-ray properties. To this aim, we processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations, and determined and analyzed different structural parameters, in order to produce a morphological classification of X-ray sources. We present the morphology of 340 X-ray emitters with optical counterpart detected. Objects have been classified by X-ray type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio. We did not find any clear correlation between X-ray and morphological types. We analyzed the angular clustering of X-ray sources with optical counterpart using two-point correlation functions. A significant positive angular clustering was obtained from a preliminary analysis of four subsamples of the X-ray sources catalog. The clustering signal of the optically extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in active galactic nuclei phenomena. Finally, we combined optical structural parameters with other X-ray and optical properties, and we confirmed an anticorrelation between the X/O ratio and the Abraham concentration index, which might suggest that early-type galaxies have lower Eddington rates than those of late-type galaxies.
17769. X-ray emitting normal galaxies from BMW-HRI
ID:
ivo://CDS.VizieR/J/A+A/435/799
Title:
X-ray emitting normal galaxies from BMW-HRI
Short Name:
J/A+A/435/799
Date:
21 Oct 2021
Publisher:
CDS
Description:
We obtained a sample of 143 normal galaxies with X-ray luminosity in the range 10^38^-10^43^erg/s from the cross-correlation of the ROSAT HRI Brera Multi-scale Wavelet (BMW-HRI) Catalogue with the Lyon-Meudon Extragalactic Database (LEDA). We find that the average X-ray properties of this sample are in good agreement with those of other samples of galaxies in the literature. We selected a complete flux limited serendipitous sample of 32 galaxies from which we derived the logN-logS distribution of normal galaxies in the flux range 1.1-110x10^-14^erg/cm^2^/s. The resulting distribution is consistent with the Euclidean -1.5 slope. Comparisons with other samples, such as the Extended Medium Sensitivity Survey, the ROSAT All Sky Survey, the XMM-Newton/2dF survey, and the Chandra Deep Field Survey indicate that the logN-logS distribution of normal galaxies is consistent with a Euclidean slope over a flux range of about 6 decades. Description:
17770. X-ray-emitting young stars in the Orion nebula
ID:
ivo://CDS.VizieR/J/ApJ/574/258
Title:
X-ray-emitting young stars in the Orion nebula
Short Name:
J/ApJ/574/258
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Orion Nebula Cluster (ONC) and the molecular cloud (OMC) in its vicinity have been observed with the ACIS-I detector on board the Chandra X-ray Observatory with 23hr exposure in two observations, on 1999 October 12 and 2000 April 1. We detect 1075 X-ray sources, most with sub-arcsecond positional accuracy. Ninety-one percent of the sources are spatially associated with known stellar members of the cluster, and an additional 7% are newly identified deeply embedded cloud members.

Limit your search

more »

more »

more »

more »

more »

more »