- ID:
- ivo://CDS.VizieR/J/ApJ/862/34
- Title:
- X-ray spectral analysis of 107 MW sight lines
- Short Name:
- J/ApJ/862/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation mechanism of the hot gaseous halo associated with the Milky Way is still under debate. We report new observational constraints on the gaseous halo using 107 lines of sight of the Suzaku X-ray observations at 75{deg}<l<285{deg} and |b|>15{deg} with a total exposure of 6.4Ms. The gaseous halo spectra are represented by a single-temperature plasma model in collisional ionization equilibrium. The median temperature of the observed fields is 0.26keV (3.0x10^6^K) with a typical fluctuation of ~30%. The emission measure varies by an order of magnitude and marginally correlates with the Galactic latitude. Despite the large scatter of the data, the emission measure distribution is roughly reproduced by a disk-like density distribution with a scale length of ~7kpc, a scale height of ~2kpc, and a total mass of ~5x10^7^M_{sun}_. In addition, we found that a spherical hot gas with the {beta}-model profile hardly contributes to the observed X-rays but that its total mass might reach >~10^9^M_{sun}_. Combined with indirect evidence of an extended gaseous halo from other observations, the hot gaseous halo likely consists of a dense disk-like component and a rarefied spherical component; the X-ray emissions primarily come from the former, but the mass is dominated by the latter. The disk-like component likely originates from stellar feedback in the Galactic disk due to the low scale height and the large scatter of the emission measures. The median [O/Fe] of ~0.25 shows the contribution of the core-collapse supernovae and supports the stellar feedback origin.
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- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/376/161
- Title:
- X-ray spectra of bursting neutron stars
- Short Name:
- J/ApJ/376/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- X-ray burst sources represent a class of accreting neutron stars in close binary systems which do not exhibit any traces of the magnetic field. We present new method of hot model atmosphere computations with account of Compton scattering on free electrons and computed set of plane-parallel hydrogen-helium atmospheres and X-ray spectra of bursting neutron stars. Models were computed with precise angle-dependent radiative transfer under constrains of radiative and hydrostatic equilibrium. Compton scattering opacity included both the Klein-Nishina corrections and the effects of relativistic Maxwellian thermal motion of scattering electrons. Compton redistribution function allows for large energy exchange between X-ray photons and scattering electrons.
- ID:
- ivo://CDS.VizieR/J/A+A/416/281
- Title:
- X-ray spectra of 4 cool stars
- Short Name:
- J/A+A/416/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These tables include the observed fluxes of the lines identified in the X-ray spectra of four cool stars (Procyon, epsilon Eri, lambda And and V851 Cen). The spectra were taken using different configurations (Chandra/LETG, Chandra/HETG and XMM/RGS). The tables list the observed fluxes at Earth, and a comparison with the fluxes predicted for a given thermal coronal structure (the Emission Measure Distribution, EMD), the emissivities provided by the Astrophysical Plasma Emission Model (APED) and column density of absorbing material in the interstellar medium towards the star. A list of the most important (at least a 5% of the flux predicted for the line) blends that have been considered for each line is included.
25255. X-ray spectrum of 1H0419-577
- ID:
- ivo://CDS.VizieR/J/A+A/556/A94
- Title:
- X-ray spectrum of 1H0419-577
- Short Name:
- J/A+A/556/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we analyze the X-ray, UV and optical data of the Seyfert 1.5 galaxy 1H0419-577, with the aim of detecting and studying an ionized-gas outflow. The source was observed simultaneously in the X-rays with XMM-Newton and in the UV with HST-COS. Optical data were also acquired with the XMM-Newton Optical Monitor. We detected a thin, lowly ionized warm absorber (logxi~0.03, logNH~19.9cm^-2^) in the X-ray spectrum, consistent to be produced by the same outflow already detected in the UV. Provided the gas density estimated in the UV, the outflow is consistent to be located in the host galaxy, at ~kpc scale. Narrow emission lines were detected in the X-rays, in the UV and also in the optical spectrum. A single photoionized-gas model cannot account for all the narrow lines emission, indicating that the narrow line region is probably a stratified environment, differing in density and ionization. X-ray lines are unambiguously produced in a more highly ionized gas phase than the one emitting the UV lines. The analysis suggests also that the X-ray emitter may be just a deeper portion of the same gas layer producing the UV lines. Optical lines are probably produced in another, disconnected gas system. The different ionization condition, and the ~pc scale location suggested by the line width for the narrow lines emitters, argue against a connection between the warm absorber and the narrow line region in this source.
25256. X-ray spectrum of SV Cam
- ID:
- ivo://CDS.VizieR/J/A+A/445/673
- Title:
- X-ray spectrum of SV Cam
- Short Name:
- J/A+A/445/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The eclipsing active binary SV Cam (G0V/K6V, P_orb_=0.593071d) was observed with XMM-Newton during two campaigns in 2001 and 2003.
- ID:
- ivo://CDS.VizieR/J/AJ/162/92
- Title:
- 126 X-rays sources around the cepheid {eta} Aql
- Short Name:
- J/AJ/162/92
- Date:
- 14 Mar 2022 07:02:20
- Publisher:
- CDS
- Description:
- X-ray bursts have recently been discovered in the Cepheids {delta}Cep and {beta}Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid {eta}Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in {delta}Cep. No X-rays were seen from the Cepheid {eta}Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/2917
- Title:
- X-rays sources in Trumpler 37
- Short Name:
- J/MNRAS/426/2917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rich young stellar clusters produce HII regions whose expansion into the nearby molecular cloud is thought to trigger the formation of new stars. However, the importance of this mode of star formation is uncertain. This investigation seeks to quantify triggered star formation (TSF) in IC 1396A (aka the Elephant Trunk Nebula), a bright-rimmed cloud (BRC) on the periphery of the nearby giant HII region IC 1396 produced by the Trumpler 37 cluster. X-ray selection of young stars from Chandra X-ray Observatory data is combined with existing optical and infrared surveys to give a more complete census of the TSF population. Over 250 young stars in and around IC 1396A are identified; this doubles the previously known population. A spatio-temporal gradient of stars from the IC 1396A cloud towards the primary ionizing star HD 206267 is found.
- ID:
- ivo://CDS.VizieR/J/ApJ/865/43
- Title:
- X-ray stacking analysis of Chandra-COSMOS gal.
- Short Name:
- J/ApJ/865/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an X-ray stacking analysis of ~75000 star-forming galaxies between 0.1<z<5.0 using the Chandra COSMOS-Legacy survey to study the X-ray emission of low-luminosity active galactic nuclei (AGN) and its connection to host galaxy properties. The stacks at z<0.9 have luminosity limits as low as 10^40^-10^41^erg/s, a regime in which X-ray binaries (XRBs) can dominate the X-ray emission. Comparing the measured luminosities to established XRB scaling relations, we find that the redshift evolution of the luminosity per star formation rate (SFR) of XRBs depends sensitively on the assumed obscuration and may be weaker than previously found. The XRB scaling relation based on stacks from the Chandra Deep Field South overestimates the XRB contribution to the COSMOS high specific SFR stacks, possibly due to a bias affecting the CDF-S stacks because of their small galaxy samples. After subtracting the estimated XRB contribution from the stacks, we find that most stacks at z>1.3 exhibit a significant X-ray excess indicating nuclear emission. The AGN emission is strongly correlated with stellar mass but does not exhibit an additional correlation with SFR. The hardness ratios of the high-redshift stacks indicate that the AGN are substantially obscured (N_H_~10^23^cm^-2^). These obscured AGN are not identified by IRAC color selection and have L_X_~10^41^-10^43^erg/s, consistent with accretion at an Eddington rate of ~10^-3^ onto 10^7^-10^8^M_{sun}_ black holes. Combining our results with other X-ray studies suggests that AGN obscuration depends on stellar mass and an additional variable, possibly the Eddington rate.
- 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.
