X-ray scaling properties of early-type galaxies

O’Sullivan, Ewan; Ponman, T. J.; Collins, R. S.

doi:10.1046/j.1365-8711.2003.06396.x

Cited by 127 publications

(155 citation statements)

References 74 publications

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“…With ROSAT PSPC observations, O'Sullivan et al (2003) found that the relation between the central stellar velocity dispersion and the temperature obtained from X-ray emission is similar to that for clusters and the relation between the X-ray luminosity and the temperature has a steep slope comparable to that found for galaxy groups.…”

Section: Introductionmentioning

confidence: 55%

Gravitational potential and X-ray luminosities of early-type galaxies observed with XMM-Newton and Chandra

Nagino¹,

Matsushita²

2009

A&A

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Aims. We study the dark matter content in early-type galaxies and investigate whether X-ray luminosities of early-type galaxies are determined by the surrounding gravitational potential. Methods. We derived gravitational mass profiles of 22 early-type galaxies observed with XMM-Newton and Chandra. Results. Sixteen galaxies show constant or decreasing radial temperature profiles, and their X-ray luminosities are consistent with kinematical energy input from stellar mass loss. The temperature profiles of the other 6 galaxies increase with radius, and their X-ray luminosities are significantly higher. The integrated mass-to-light ratio of each galaxy is constant at that of stars within 0.5-1 r e , and increases with radius, where r e is the effective radius of a galaxy. The scatter of the central mass-to-light ratio of galaxies was less in K-band light. At 3 r e , the integrated mass-to-light ratios of galaxies with flat or decreasing temperature profiles are twice the value at 0.5 r e , where the stellar mass dominates, and at 6 r e , these increase to three times the value at 0.5 r e . Conclusions. This feature should reflect common dark and stellar mass distributions in early-type galaxies: within 3 r e , the mass of dark matter is similar to the stellar mass, while within 6 r e , the former is larger than the latter by a factor of two. In contrast, X-ray luminous galaxies have higher gravitational mass in the outer regions than X-ray faint galaxies. We describe these X-ray luminous galaxies as the central objects of large potential structures; the presence or absence of this potential is the main source of the large scatter in the X-ray luminosity.

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Section: Introductionmentioning

confidence: 55%

Gravitational potential and X-ray luminosities of early-type galaxies observed with XMM-Newton and Chandra

Nagino¹,

Matsushita²

2009

A&A

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“…The observed L X -kT relation of FJ sources is shown in Figure 6 with previous works obtained from early-type galaxies, groups of galaxies, and clusters of galaxies (White et al 1997;Xue & Wu 2000;O'Sullivan et al 2003) for comparison, and the possible origins and corresponding objects for FJ sources discussed above are summarized in Table 5. Note that luminosities for FJ sources without redshift information were not calculated and therefore Figure 6 does not include them.…”

Section: Corresponding Object and Origin Of Fj Sourcesmentioning

confidence: 74%

EXPLORING HOT GAS AT JUNCTIONS OF GALAXY FILAMENTS WITHSUZAKU

Mitsuishi

Kawahara

Sekiya

et al. 2014

ApJ

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We performed five pointing observations with Suzaku to search for hot gases associated with the junctions of galaxy filaments where no significant diffuse X-ray sources were previously detected. We discovered X-ray sources successfully in all five regions including merging groups of galaxies, Suzaku J0957+2610 and Suzaku J1134+2105, and analyzed two bright sources in each field. Spectral analysis indicates that three sources originate from X-ray diffuse halos associated with optically bright galaxies or groups of galaxies with kT ∼ 0.6-0.8 keV. The three other sources are possibly group-and cluster-scale X-ray halos with temperatures of ∼1 keV and ∼4 keV, respectively while the others are compact object origins such as active galactic nuclei. All of the three observed intracluster media within the junctions of the galaxy filaments previously found are involved in ongoing mergers. Thus, we demonstrate that deep X-ray observations at the filament junctions identified by galaxy surveys are a powerful means to explore previously undetected growing halos in a hierarchical structure.

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“…The value of r c in most other galaxies with hot gas is less than 1 kpc, which is significantly smaller than the radius of closest approach for all objects in the sample. Therefore, the value of r c is not relevant for our sample, and we can write the density function as a power law, n / r À3 , and we choose to examine n / r À3/2 , as this is similar to that found for the hot gas in ellipticals ( ¼ 1/2 in the ''beta'' models used for ellipticals; e.g., O'Sullivan et al 2003). While this leads to a gas mass that increases with radius as r 3/2 and an emission measure that increases logarithmically with radius, the column density is convergent at large radius.…”

Section: Galactic Halo Modelsmentioning

confidence: 99%

X‐Ray Absorption from the Milky Way Halo and the Local Group

Bregman

Lloyd-Davies

2007

ApJ

144

154

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Million degree gas is present at near-zero redshift and is due to either a gaseous Galactic halo or a more diffuse but very massive Local Group medium. We can discriminate between these models because the column densities should depend on location in the sky, either relative to the Galaxy bulge or to the M31YMilky Way axis. To search for these signatures, we measured the O vii K absorption-line strength toward 25 bright active galactic nuclei (AGNs), plus LMC X-3, using XMM-Newton RGS archival data. The data are in conflict with a purely Local Group model, but support the Galactic halo model. The strongest correlation is between the O vii equivalent widths and the ROSAT background emission measurement in the R45 band (0.4 Y1 keV ), for which O vii emission makes the largest single contribution. This suggests that much of the O vii emission and absorption are cospatial, from which the radius of a uniform halo appears to lie the range 15Y110 kpc. The present data do not constrain the type of halo gas model, and an equally good fit is obtained in a model where the gas density decreases as a power law, such as r À3/2 . For a uniform halo with a radius of 20 kpc, the electron density would be 9 ; 10 À4 cm À3 , and the gas mass is 4 ; 10 8 M . The redshift of the four highest signal-to-noise ratio (S/N ) O vii measurements is consistent with a Milky Way origin rather than a Local Group origin.

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X-ray scaling properties of early-type galaxies

Cited by 127 publications

References 74 publications

Gravitational potential and X-ray luminosities of early-type galaxies observed with XMM-Newton and Chandra

Gravitational potential and X-ray luminosities of early-type galaxies observed with XMM-Newton and Chandra

EXPLORING HOT GAS AT JUNCTIONS OF GALAXY FILAMENTS WITHSUZAKU

X‐Ray Absorption from the Milky Way Halo and the Local Group

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