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2171. 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.
2172. 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:
2173. 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.
2174. X-ray measurements of ChaMP-SDSS galaxies
ID:
ivo://CDS.VizieR/J/ApJ/705/1336
Title:
X-ray measurements of ChaMP-SDSS galaxies
Short Name:
J/ApJ/705/1336
Date:
21 Oct 2021
Publisher:
CDS
Description:
The combination of the Sloan Digital Sky Survey (SDSS) and the Chandra Multiwavelength Project (ChaMP; Green et al. 2004ApJS..150...43G) currently offers the largest and most homogeneously selected sample of nearby galaxies for investigating the relation between X-ray nuclear emission, nebular line emission, black hole masses, and properties of the associated stellar populations. We provide X-ray spectral fits and valid uncertainties for all the galaxies with counts ranging from 2 to 1325 (mean 76, median 19). We present here novel constraints that both X-ray luminosity L_X_ and X-ray spectral energy distribution bring to the galaxy evolutionary sequence HII->Seyfert/Transition Object->LINER->Passive suggested by optical data.
2175. X-ray & MIR AGNs in Stripe 82 with eBOSS spectra
ID:
ivo://CDS.VizieR/J/ApJ/876/50
Title:
X-ray & MIR AGNs in Stripe 82 with eBOSS spectra
Short Name:
J/ApJ/876/50
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of a Sloan Digital Sky Survey IV eBOSS program to target X-ray sources and mid-infrared-selected Wide-field Infrared Survey Explorer (WISE) active galactic nucleus (AGN) candidates in a 36.8deg^2^ region of Stripe 82. About half this survey (15.6deg^2^) covers the largest contiguous portion of the Stripe 82 X-ray survey. This program represents the largest spectroscopic survey of AGN candidates selected solely by their WISE colors. We combine this sample with X-ray and WISE AGNs in the field identified via other sources of spectroscopy, producing a catalog of 4847 sources that is 82% complete to r~22. Based on X-ray luminosities or WISE colors, 4730 of these sources are AGNs, with a median sample redshift of z~1. About 30% of the AGNs are optically obscured (i.e., lack broad lines in their optical spectra). BPT analysis, however, indicates that 50% of the WISE AGNs at z<0.5 have emission line ratios consistent with star-forming galaxies, so whether they are buried AGNs or star-forming galaxy contaminants is currently unclear. We find that 61% of X-ray AGNs are not selected as mid-infrared AGNs, with 22% of X-ray AGNs undetected by WISE. Most of these latter AGNs have high X-ray luminosities (Lx>10^44^erg/s), indicating that mid-infrared selection misses a sizable fraction of the highest luminosity AGNs, as well as lower luminosity sources where AGN-heated dust is not dominating the mid-infrared emission. Conversely, ~58% of WISE AGNs are undetected by X-rays, though we do not find that they are preferentially redder than the X-ray-detected WISE AGNs.
2176. 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).
2177. X-ray/radio data of high energy peaked BL Lacs
ID:
ivo://CDS.VizieR/J/A+A/434/385
Title:
X-ray/radio data of high energy peaked BL Lacs
Short Name:
J/A+A/434/385
Date:
21 Oct 2021
Publisher:
CDS
Description:
The fully identified complete sample including 150 extreme HBL BL Lacs is presented in Table 1 where we give the source name built with the catalog identification code SHBL (where S stands for "Sedentary" survey and HBL for High energy peaked BL Lacs) and the arcsecond precision optical coordinates of the source taken from the APM and COSMOS on-line services; we give also the RASS name, the X-ray flux (0.1-2.4keV), the radio flux (20cm, from the NVSS survey), and the optical apparent V magnitude (from APM and COSMOS) respectively; we give the redshift when available and the reference for the optical identification. In Table 2 we report properties for five bright elliptical galaxies/low luminosity HBLs in the original sample of high fX/fr sources of Paper I (Giommi et al., 1999MNRAS.310..465G). In Table 3 the 19 rejected emission line AGNs together with their properties are presented.
2178. X-ray spectra in 13^H^ XMM/Chandra deep field
ID:
ivo://CDS.VizieR/J/MNRAS/369/156
Title:
X-ray spectra in 13^H^ XMM/Chandra deep field
Short Name:
J/MNRAS/369/156
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the X-ray spectra of 86 optically identified sources in the 13^H^ XMM-Newton/Chandra deep field which have >70 X-ray counts. The majority of these sources have 2-10keV fluxes between 10-15 and 5x10^-14^erg/cm^2^/s. The sample consists of 50 broad-line active galactic nuclei (BLAGN), 25 narrow emission-line galaxies (NELGs), six absorption-line galaxies and five Galactic stars. The majority (42/50) of the BLAGN have X-ray spectra which are consistent with a power-law shape.
2179. X-ray spectral analysis of Swift/BAT AGNs
ID:
ivo://CDS.VizieR/J/ApJ/763/111
Title:
X-ray spectral analysis of Swift/BAT AGNs
Short Name:
J/ApJ/763/111
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed X-ray spectral analysis of the non-beamed, hard X-ray selected active galactic nuclei (AGNs) in the northern Galactic cap of the 58 month Swift Burst Alert Telescope (Swift/BAT) catalog, consisting of 100 AGNs with b>50{deg}. This sky area has excellent potential for further dedicated study due to a wide range of multi-wavelength data that are already available, and we propose it as a low-redshift analog to the "deep field" observations of AGNs at higher redshifts (e.g., CDFN/S, COSMOS, Lockman Hole). We present distributions of luminosity, absorbing column density, and other key quantities for the catalog. We use a consistent approach to fit new and archival X-ray data gathered from XMM-Newton, Swift/XRT, ASCA, and Swift/BAT. We probe to deeper redshifts than the 9 month BAT catalog (<z>=0.043 compared to <z>=0.03 for the 9 month catalog), and uncover a broader absorbing column density distribution. The fraction of obscured (logN_H_>=22) objects in the sample is ~60%, and 43%-56% of the sample exhibits "complex" 0.4-10keV spectra. We present the average 1-10keV spectrum for the sample, which reproduces the 1-10keV X-ray background slope as found for the brighter 9 month BAT AGN sample.
2180. X-ray star clusters in the Carina complex
ID:
ivo://CDS.VizieR/J/ApJS/194/9
Title:
X-ray star clusters in the Carina complex
Short Name:
J/ApJS/194/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
The distribution of young stars found in the Chandra Carina Complex Project (CCCP) is examined for clustering structure. X-ray surveys are advantageous for identifying young stellar populations compared to optical and infrared surveys in suffering less contamination from nebular emission and Galactic field stars. The analysis is based on smoothed maps of a spatially complete subsample of ~3000 brighter X-ray sources classified as Carina members and ~10000 stars from the full CCCP sample. The principal known clusters are recovered, and some additional smaller groups are identified. No rich embedded clusters are present, although a number of sparse groups are found. The CCCP reveals considerable complexity in clustering properties.