Athena: the X-ray observatory to study the hot and energetic Universe

Barcons, X.; Nandra, K.; Barret, D.; Herder, J. den; Fabian, A. C.; Piro, L.; Watson, M. G.

doi:10.1088/1742-6596/610/1/012008

Cited by 83 publications

(62 citation statements)

References 4 publications

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“…By utilizing future non-dispersive, high-resolution X-ray spectrometer onboard DIOS (Ohashi et al 2014) and Athena (Barcons et al 2015), emission lines from ionized ions of intergalactic warmhot gas are expected to be more clearly detected. The X-IFU micro-calorimeter onboard Athena will achieve a superior energy resolution of approximately 2.5 eV (Ravera et al 2014;Gottardi et al 2016).…”

Section: Future Prospects Of the Whim Searchmentioning

confidence: 99%

Search for the warm–hot intergalactic medium around A 2744 using Suzaku

Hattori

Ota

Zhang

et al. 2017

Publications of the Astronomical Society of Japan

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We present the results from the Suzaku satellite of the surrounding region of a galaxy cluster, A2744, at z = 0.3. To search for oxygen emission lines from the warm-hot intergalactic medium (WHIM), we analyzed X-ray spectra from two northeast regions 2.2-3.3 and 3.3-4.4 Mpc from the center of the cluster, which offers the first test on the presence of a WHIM near the typical accretion shock radius (∼ 2r 200 ) predicted by hydrodynamical simulations. For the 2.2-3.3 Mpc region, the spectral fit significantly (99.2% significance) improved when we include O VII and O VIII lines in the spectral model. A comparable WHIM surface brightness was obtained in the 3.3-4.4 Mpc region and the redshift of O VIII line is consistent with z = 0.3 within errors. The present results support that the observed soft X-ray emission originated from the WHIM. However, considering both statistical and systematic uncertainties, O VIII detection in the northeast regions was marginal. The surface brightness of the O VIII line in 10 −7 photons cm −2 s −1 arcmin −2 was measured to be 2.7 ± 1.0, 2.1 ± 1.2 for the 2.2-3.3, 3.3-4.4 Mpc regions, giving the upper limit on the baryon overdensity of δ = 319(< 443), 283(< 446), respectively. This is comparable with previous observations of cluster outskirts and their theoretical predictions. The future prospect for WHIM detection using the Athena X-IFU microcalorimeter is briefly discussed here. In addition, we also derived the ICM temperature distribution of A2744 to detect a clear discontinuity at the location of the radio relic. This suggests that the cluster has undergone strong shock heating by mass accretion along the filament.

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Section: Future Prospects Of the Whim Searchmentioning

confidence: 99%

Search for the warm–hot intergalactic medium around A 2744 using Suzaku

Hattori

Ota

Zhang

et al. 2017

Publications of the Astronomical Society of Japan

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“…For example, even Athena, a nextgeneration X-ray observatory aiming for launch in ≈2028 (e.g., Barcons et al 2015), may not be able to reach the flux levels probed in the central region of the 7Ms CDF-S. X-ray missions capable of substantially surpassing the sensitivity of the 7Ms CDF-S, such as the X-Ray Surveyor (e.g., Weisskopf et al 2015), are presently not funded for construction. The structure of this paper is asfollows.…”

Section: Introductionmentioning

confidence: 99%

The Chandra Deep Field-South Survey: 7 MS Source Catalogs

Luo

Brandt

Xue

et al. 2016

ApJS

422

582

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We present X-ray source catalogs for the ≈7 Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2arcmin 2 . Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric extraction and significance assessment, we create a main source catalog containing 1008 sources that are detected in up to three X-ray bands: 0.5-7.0keV, 0.5-2.0keV, and 2-7keV. A supplementary source catalog is also provided,including 47 lower-significance sources that have bright (  K 23 s ) near-infrared counterparts. We identify multiwavelength counterparts for 992 (98.4%) of the main-catalog sources, and we collect redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, we identify 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous ≈4 Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. We have achieved unprecedented X-ray sensitivity with average flux limits over the central ≈1 arcmin 2 region of ≈1.9×10 −17 , 6.4×10 −18 , and 2.7×10 −17 ergcm −2 s −1 in the three X-ray bands, respectively. We provide cumulative number-count measurements observing, for the first time, that normal galaxies start to dominate the X-ray source population at the faintest 0.5-2.0keV flux levels. The highest X-ray source density reaches ≈50,500 deg −2 , and 47%±4% of these sources are AGNs (≈23,900 deg −2 ).

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“…They are, however, rare, and only in those two cases were relatively high-quality spectra obtained. We anticipate that future large-area X-ray observatories will have the capability to distinguish direct from reflected burst emission for a large sample of bursts (Wolf et al 2016), such as the Neutron Star Interior Composition Explorer (NICER, Gendreau et al 2012) and Athena (Barcons et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of X-Ray Bursts From Neutron Stars With Concave Accretion Disks

Keek

2016

ApJ

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Emission from neutron stars and accretion disks in low-mass X-ray binaries is anisotropic. The non-spherical shape of the disk as well as blocking of the neutron star by the disk make the observed flux dependent on the inclination angle of the disk with respect to the line of sight. This is of importance for the interpretation of thermonuclear X-ray bursts from neutron stars. Because part of the X-ray burst is reflected off the disk, the observed burst flux depends on the anisotropies for both direct emission from the neutron star and reflection off the disk. This influences measurements of source distance, mass accretion rate, and constraints on the neutron star's equation of state. Previous predictions of the anisotropy factors assumed a geometrically flat disk. Detailed observations of two so-called superbursts allowed for the direct and the reflected burst fluxes to each be measured separately. The reflection fraction was much higher than what the anisotropies of a flat disk can account for. We create numerical models to calculate the anisotropy factors for different disk shapes, including concave disks. We present the anisotropy factors of the direct and reflected burst fluxes separately, as well as the anisotropy of the persistent flux. Reflection fractions substantially larger than unity are produced in the case where the inner accretion disk increases steeply in height, such that part of the star is blocked from view. Such a geometry could possibly be induced by the X-ray burst if X-ray heating causes the inner disk to puff up.

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Athena: the X-ray observatory to study the hot and energetic Universe

Cited by 83 publications

References 4 publications

Search for the warm–hot intergalactic medium around A 2744 using Suzaku

Search for the warm–hot intergalactic medium around A 2744 using Suzaku

The Chandra Deep Field-South Survey: 7 MS Source Catalogs

Anisotropy of X-Ray Bursts From Neutron Stars With Concave Accretion Disks

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