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17851. X-ray sources in Galactic Center
ID:
ivo://CDS.VizieR/J/ApJ/613/1179
Title:
X-ray sources in Galactic Center
Short Name:
J/ApJ/613/1179
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the X-ray spectra and variability of the sample of X-ray sources with L_X_~10^31^-10^33^ergs/s identified within the inner 9' of the Galaxy by Muno et al. Very few of the sources exhibit intraday or intermonth variations.
17852. X-ray sources in galaxy pairs
ID:
ivo://CDS.VizieR/J/AJ/133/220
Title:
X-ray sources in galaxy pairs
Short Name:
J/AJ/133/220
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive study of the local environments of four elliptical+spiral (E+S) galaxy pairs with the main goal of investigating their formation/evolution histories. We obtained new XMM-Newton data for two pairs (RR 143 and RR 242) that complement existing ROSAT data for the other two (RR 210 and RR 216).
17853. X-ray sources in Hickson Compact Groups
ID:
ivo://CDS.VizieR/J/ApJS/212/9
Title:
X-ray sources in Hickson Compact Groups
Short Name:
J/ApJS/212/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L_X_) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices ({Gamma}), hardness ratios, and L_X_, in the full (0.5-8.0keV), soft (0.5-2.0keV), and hard (2.0-8.0keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L_X,0.5-8.0keV_>10^42^erg/s, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known {alpha}_OX_-{nu}L_{nu}(nearUV)_ correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the "non-AGN locus" in {alpha}_OX_-{nu}L_{nu}(nearUV)_ space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with M_R_<=-20 and L_X,0.5-8.0keV_>=10^41^erg/s is 0.08_-0.01_^+0.35^, somewhat higher than the ~5% fraction in galaxy clusters.
17854. X-ray sources in IC 348 from Chandra
ID:
ivo://CDS.VizieR/J/AJ/122/866
Title:
X-ray sources in IC 348 from Chandra
Short Name:
J/AJ/122/866
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained a deep (53 ks) X-ray image of the very young stellar cluster IC 348 with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. In our image with a sensitivity limit of ~1x10^28^ergs/s (more than 10 times deeper than our ROSAT images of IC 348), 215 X-ray sources are detected. While 115 of these sources can be identified with known cluster members, 58 X-ray sources are most likely new, still unidentified cluster members. About 80% of all known cluster members with masses between ~0.15 and 2M_{sun}_ are visible as X-ray sources in our image. We discover X-ray emission at levels of ~10^28^ergs/s from four of 13 known brown dwarfs and from three of 12 brown dwarf candidates in IC 348. We also detect X-ray emission from two deeply embedded objects, presumably class I protostars, south of the cluster center. Description:
17855. X-ray sources in IC 1396N
ID:
ivo://CDS.VizieR/J/ApJ/654/316
Title:
X-ray sources in IC 1396N
Short Name:
J/ApJ/654/316
Date:
21 Oct 2021
Publisher:
CDS
Description:
The IC 1396N cometary globule (CG) within the large nearby HII region IC 1396 has been observed with the ACIS detector on board the Chandra X-Ray Observatory. We detect 117 X-ray sources, of which ~50-60 are likely members of the young open cluster Trumpler 37 dispersed throughout the HII region, and 25 are associated with young stars formed within the globule. Infrared photometry (2MASS and Spitzer) shows that the X-ray population is very young: 3 older Class III stars, 16 classical T Tauri stars, and 6 protostars including a Class 0/I system.
17856. X-ray sources in M104
ID:
ivo://CDS.VizieR/J/ApJ/599/1067
Title:
X-ray sources in M104
Short Name:
J/ApJ/599/1067
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the population of point sources discovered during an 18.5ks Chandra ACIS-S observation of the Sombrero galaxy. We present the luminosity function and the spectra of the six brightest sources, consider correlations with globular clusters (GCs) and with planetary nebulae, and study the galaxy's population of very soft sources. We detected 122 sources. Twenty-two sources are identified as very soft; of these, five appear to be classical luminous supersoft X-ray sources (SSSs), while 17 may belong to the slightly harder class referred to as quasi-soft (QSSs). There is an overdensity of very soft sources within 2kpc of the nucleus, which is itself the brightest X-ray source. Very soft sources are also found in the disk and halo, with one QSS in a globular cluster (GC).
17857. X-ray Sources in Molecular Clouds
ID:
ivo://CDS.VizieR/J/A+AS/128/331
Title:
X-ray Sources in Molecular Clouds
Short Name:
J/A+AS/128/331
Date:
21 Oct 2021
Publisher:
CDS
Description:
Figure 9: Finding charts for the objects where spectra were taken, based on the APM data base. The cross is centered at the X-ray position. 30 arcsec radius error circles are shown and arrows mark the objects with the available spectra. North is up and East to the left in all charts. Figure 10: Deep CCD images of the X-ray source fields with faint optical counterparts. Circles with 30 arcsec radius are centered on the X-ray position. Capital letters identify the brightest object next to them (see Table 3 for remarks on identification). The filter used and the exposure time are shown above each image in brackets.
17858. X-ray sources in NGC 5866
ID:
ivo://CDS.VizieR/J/ApJ/706/693
Title:
X-ray sources in NGC 5866
Short Name:
J/ApJ/706/693
Date:
21 Oct 2021
Publisher:
CDS
Description:
S0 galaxies are often thought to be passively evolved from spirals after star formation is quenched. To explore what is actually occurring in such galaxies, we present a multi-wavelength case study of NGC 5866 - a nearby edge-on S0 galaxy in a relatively isolated environment. This study shows strong evidence for dynamic activities in the interstellar medium, which are most likely driven by supernova explosions in the galactic disk and bulge. Understanding these activities can have strong implications for studying the evolution of such galaxies. We utilize Chandra, Hubble Space Telescope, and Spitzer data as well as ground-based observations to characterize the content, structure, and physical state of the medium and its interplay with the stellar component in NGC 5866. We reveal the presence of diffuse X-ray-emitting hot gas, which extends as far as 3.5kpc away from the galactic plane and can be heated easily by Type Ia SNe in the bulge.
17859. X-ray sources in NGC 1600
ID:
ivo://CDS.VizieR/J/ApJ/617/262
Title:
X-ray sources in NGC 1600
Short Name:
J/ApJ/617/262
Date:
21 Oct 2021
Publisher:
CDS
Description:
We observed the X-ray-bright E3 galaxy NGC 1600 and nearby members of the NGC 1600 group with the Chandra X-Ray Observatory ACIS-S3 to study their X-ray properties. Unresolved emission dominates the observation; however, we resolved some of the emission into 71 sources, most of which are low-mass X-ray binaries associated with NGC 1600. Twenty-one of the sources have L_X_>2x10^39^ergs/s (0.3-10.0keV; assuming they are at the distance of NGC 1600), marking them as ultraluminous X-ray point source (ULX) candidates; we expect that only 11+/-2 are unrelated foreground/background sources.
17860. X-ray sources in NGC 4261
ID:
ivo://CDS.VizieR/J/ApJ/634/272
Title:
X-ray sources in NGC 4261
Short Name:
J/ApJ/634/272
Date:
21 Oct 2021
Publisher:
CDS
Description:
Chandra images of the elliptical galaxy NGC 4261 have revealed an anisotropy in the spatial distribution of the off-nuclear X-ray sources, interpreted by Zezas et al. (2003ApJ...599L..73Z) as evidence of an association with a young stellar population. Our independent analysis of archive X-ray (Chandra) and optical (INT and HST) observations confirms the anisotropy of the X-ray sources but conducts to a different interpretation for their origin.

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