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991. 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:
992. X-ray ETGs properties in the Chandra COSMOS survey
ID:
ivo://CDS.VizieR/J/ApJ/790/16
Title:
X-ray ETGs properties in the Chandra COSMOS survey
Short Name:
J/ApJ/790/16
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study a sample of 69 X-ray detected early-type galaxies (ETGs), selected from the Chandra COSMOS survey, to explore the relation between the X-ray luminosity of hot gaseous halos (L_X, gas_) and the integrated stellar luminosity (L_K_) of the galaxies, in a range of redshift extending out to z = 1.5. In the local universe, a tight, steep relationship has been established between these two quantities (L_x.gas_ ~ L_K_^4.5^), suggesting the presence of largely virialized halos in X-ray luminous systems. We use well-established relations from the study of local universe ETGs, together with the expected evolution of the X-ray emission, to subtract the contribution of low-mass X-ray binary populations from the X-ray luminosity of our sample. Our selection minimizes the presence of active galactic nuclei (AGNs), yielding a sample representative of normal passive COSMOS ETGs; therefore, the resulting luminosity should be representative of gaseous halos, although we cannot exclude other sources such as obscured AGNs or enhanced X-ray emission connected with embedded star formation in the higher-z galaxies. We find that most of the galaxies with estimated L_X_< 10^42^ erg/s and z < 0.55 follow the L_X, gas_-L_K_ relation of local universe ETGs. For these galaxies, the gravitational mass can be estimated with a certain degree of confidence from the local virial relation. However, the more luminous (10^42^ erg/s <L_X_< 10^43.5^ erg/s) and distant galaxies present significantly larger scatter; these galaxies also tend to have younger stellar ages. The divergence from the local L_X, gas_-L_K_relation in these galaxies implies significantly enhanced X-ray emission up to a factor of 100 larger than predicted from the local relation. We discuss the implications of this result for the presence of hidden AGNs, and the evolution of hot halos, in nuclear and star formation feedback.
993. X-ray group of galaxies in AEGIS
ID:
ivo://CDS.VizieR/J/ApJ/765/117
Title:
X-ray group of galaxies in AEGIS
Short Name:
J/ApJ/765/117
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z~0.066-1.544 and virial mass range M_200_~1.3-13.3x10^13^^M_{sun}_. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.
994. X-ray luminosities of early-type galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/328/461
Title:
X-ray luminosities of early-type galaxies
Short Name:
J/MNRAS/328/461
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalogue of X-ray luminosities for 401 early-type galaxies, of which 136 are based on newly analysed ROSAT PSPC pointed observations (Cat. <IX/30>). The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. Using this sample we fit the L_X_/L_B_ relation for early-type galaxies and find a best-fit slope for the catalogue of ~2.2. We demonstrate the influence of group-dominant galaxies on the fit and present evidence that the relation is not well modelled by a single power-law fit. We also derive estimates of the contribution to galaxy X-ray luminosities from discrete-sources and conclude that they provide L_(discrete-source-contribution)_/L_B_~29.5erg/s/L_B{sun}_. We compare this result with luminosities from our catalogue. Lastly, we examine the influence of environment on galaxy X-ray luminosity and on the form of the L_X_/L_B_ relation. We conclude that although environment undoubtedly affects the X-ray properties of individual galaxies, particularly those in the centres of groups and clusters, it does not change the nature of whole populations.
995. X-ray/NIR correlation for early-type galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/367/627
Title:
X-ray/NIR correlation for early-type galaxies
Short Name:
J/MNRAS/367/627
Date:
21 Oct 2021
Publisher:
CDS
Description:
The relation between X-ray luminosity and near-infrared (NIR) luminosity for early-type galaxies has been examined. NIR luminosities should provide a superior measure of stellar mass compared to optical luminosities used in previous studies, especially if there is significant star formation or dust present in the galaxies. However, we show that the X-ray-NIR relations are remarkably consistent with the X-ray-optical relations. This indicates that the large scatter of the relations is dominated by scatter in the X-ray properties of early-type galaxies, and is consistent with early-types consisting of old, quiescent stellar populations. We have investigated scatter in terms of environment, surface brightness profile, Mg2, H{beta}, H{gamma} line strength indices, spectroscopic age and nuclear H{alpha} emission.
996. X-ray observations of HCG galaxies
ID:
ivo://CDS.VizieR/J/ApJ/817/95
Title:
X-ray observations of HCG galaxies
Short Name:
J/ApJ/817/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
We obtain total galaxy X-ray luminosities, L_X_, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of our galaxies, we find that the detected point sources most likely are local to their associated galaxy, and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic nuclei (AGNs). For spiral and irregular galaxies, we find that, after accounting for AGNs and nuclear sources, most CG galaxies are either within the +/-1{sigma} scatter of the Mineo et al. L_X_-star formation rate (SFR) correlation or have higher L_X_ than predicted by this correlation for their SFR. We discuss how these "excesses" may be due to low metallicities and high interaction levels. For elliptical and S0 galaxies, after accounting for AGNs and nuclear sources, most CG galaxies are consistent with the Boroson et al. L_X_-stellar mass correlation for low-mass XRBs, with larger scatter, likely due to residual effects such as AGN activity or hot gas. Assuming non-nuclear sources are low- or high-mass XRBs, we use appropriate XRB luminosity functions to estimate the probability that stochastic effects can lead to such extreme L_X_ values. We find that, although stochastic effects do not in general appear to be important, for some galaxies there is a significant probability that high L_X_ values can be observed due to strong XRB variability.
997. 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.
998. X-ray properties of optically selected ETGs
ID:
ivo://CDS.VizieR/J/MNRAS/422/494
Title:
X-ray properties of optically selected ETGs
Short Name:
J/MNRAS/422/494
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z~~0.0-1.2 in the Chandra Deep Fields (CDFs). To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z=0.1-1.2 in the ~~4Ms CDF-South and ~~2Ms CDF-North and z=0.1-0.6 in the ~~250ks Extended-CDF-South where the contribution from individually undetected active galactic nuclei (AGN) is expected to be negligible in our stacking.
999. X-Shooter Spectral Library (XSL). DR1
ID:
ivo://CDS.VizieR/J/A+A/565/A117
Title:
X-Shooter Spectral Library (XSL). DR1
Short Name:
J/A+A/565/A117
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first release of XSL, the X-Shooter Spectral Library observed at the European Southern Observatory (ESO). This release contains 237 stars spanning the wavelengths 3000-10200{AA} observed at a resolving power R~10000. Telluric standard stars used to correct the Earth atmospheric contamination are presented as well.
1000. X-Shooter Spectral Library (XSL). DR2
ID:
ivo://CDS.VizieR/J/A+A/634/A133
Title:
X-Shooter Spectral Library (XSL). DR2
Short Name:
J/A+A/634/A133
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the second data release (DR2) of the X-Shooter Spectral Library (XSL), which contains all the spectra obtained over the six semesters of that program. This release supersedes our first data release from 2014, with a larger number of spectra (813 observations of 666 stars) and with a more extended wavelength coverage as the data from the near-infrared arm of the X-Shooter spectrograph are now included. The DR2 spectra then consist of three segments that were observed simultaneously and, if combined, cover the range between 300nm and 2.45um at a spectral resolving power close to R=10000. The spectra were corrected for instrument transmission and telluric absorption, and they were also corrected for wavelength-dependent flux-losses in 85% of the cases. On average, synthesized broad-band colors agree with those of the MILES library and of the combined IRTF and Extended IRTF libraries to within 1%. The scatter in these comparisons indicates typical errors on individual colors in the XSL of 2-4%. The comparison with 2MASS point source photometry shows systematics of up to 5% in some colors, which we attribute mostly to zero-point or transmission curve errors and a scatter that is consistent with the above uncertainty estimates. The final spectra were corrected for radial velocity and are provided in the rest-frame (with wavelengths in air). The spectra cover a large range of spectral types and chemical compositions (with an emphasis on the red giant branch), which makes this library an asset when creating stellar population synthesis models or for the validation of near-ultraviolet to near-infrared theoretical stellar spectra across the Hertzsprung-Russell diagram.

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