The Einstein Observatory Extended Medium-Sensitivity Survey. I - X-ray data and analysis

Gioia, I. M.; Maccacaro, T.; Schild, Rudolph E.; Wolter, A.; Stocke, John T.; Morris, Simon L.; Henry, J. P.

doi:10.1086/191426

Cited by 451 publications

(426 citation statements)

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“…A summary of the properties of the four target SBs appears in Table 1. Each of these binaries was detected as an X-ray source by the Einstein observatory (Ku, Righini-Cohen, & Simon 1982;Walter 1986;Mathieu et al 1989;Gioia et al 1990); all are weak-lined T Tauri stars with deep photospheric absorption lines. The velocities have already been well determined, from optical observations, for these four systems .…”

Section: Resultsmentioning

confidence: 99%

The Smallest Mass Ratio Young Star Spectroscopic Binaries

Prato

Simon

Mazeh

et al. 2002

ApJ

101

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Using high-resolution near-infrared spectroscopy with the Keck Telescope, we have detected the radial velocity signatures of the cool secondary components in four optically identified pre-main-sequence, singlelined spectroscopic binaries. All are weak-lined T Tauri stars with well-defined center-of-mass velocities. The mass ratio for one young binary, NTTS 160905À1859, is M 2 /M 1 = 0.18 AE 0.01, the smallest yet measured dynamically for a pre-main-sequence spectroscopic binary. These new results demonstrate the power of infrared spectroscopy for the dynamical identification of cool secondaries. Visible-light spectroscopy, to date, has not revealed any pre-main-sequence secondary stars with masses <0.5 M , while two of the young systems reported here are in that range. We compare our targets with a compilation of the published young, double-lined spectroscopic binaries and discuss our unique contribution to this sample.

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Section: Resultsmentioning

confidence: 99%

The Smallest Mass Ratio Young Star Spectroscopic Binaries

Prato

Simon

Mazeh

et al. 2002

ApJ

101

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“…Our high-redshift sample is from the Einstein Extended Medium Sensitivity Survey (EMSS) (Gioia et al 1990) cluster sample (Gioia & Luppino 1994), with the following selection criteria: 0.3 ≤ z ! 0.4, d(1950) ≥ Ϫ40Њ, and F det (0.3, 3.5) ≥ 2.5 # 10 Ϫ13 ergs cm Ϫ2 s Ϫ1 .…”

Section: Observational Resultsmentioning

confidence: 99%

A Measurement of the Density Parameter Derived from the Evolution of Cluster X-Ray Temperatures

Henry¹

1997

The Astrophysical Journal

172

175

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We have, for the first time, determined the cluster X-ray temperature function at a redshift other than zero. The observed evolution of the temperatures is mild to a redshift of one-third. The normalization of the luminositytemperature relation is 0.92 ‫ע‬ 0.07 of the low-redshift relation (1 j error), assuming that its shape is the same. Such behavior occurs when clusters form with constant central entropy. The evolution of the temperature function implies that Q 0 is 0.50 ‫ע‬ 0.14 assuming an open universe, or 0.55 ‫ע‬ 0.17 assuming that a cosmological constant produces a flat universe (1 j symmetrized errors)

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“…The M wl 500 -M hyd 500 relation Comparison with Mahdavi et al (2013) results: recently, M13 published scaling relations observed between the weak lensing and X-ray masses for a sample of 50 massive clusters, partly based on the brightest clusters from the Einstein Observatory Extended Medium Sensitivity Survey (Gioia et al 1990). Weak lensing masses for the M13 sample have been obtained from CFHT/Megacam imaging , while the X-ray analysis combines XMM-Newton and Chandra data.…”

Section: Comparison With Previous Workmentioning

confidence: 91%

The 400d Galaxy Cluster Survey weak lensing programme

Israel

Reiprich²,

Erben³

et al. 2014

A&A

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Context. Scaling properties of galaxy cluster observables with cluster mass provide central insights into the processes shaping clusters. Calibrating proxies for cluster mass that are relatively cheap to observe will moreover be crucial to harvest the cosmological information available from the number and growth of clusters with upcoming surveys like eROSITA and Euclid. The recent Planck results led to suggestions that X-ray masses might be biased low by ∼40%, more than previously considered. Aims. We aim to extend knowledge of the weak lensing -X-ray mass scaling towards lower masses (as low as 1 × 10 14 M ) in a sample representative of the z ∼ 0.4-0.5 population. Thus, we extend the direct calibration of cluster mass estimates to higher redshifts. Methods. We investigate the scaling behaviour of MMT/Megacam weak lensing (WL) masses for 8 clusters at 0.39 ≤ z ≤ 0.80 as part of the 400d WL programme with hydrostatic Chandra X-ray masses as well as those based on the proxies, e.g. Y X = T X M gas . Results. Overall, we find good agreement between WL and X-ray masses, with different mass bias estimators all consistent with zero. When subdividing the sample into a low-mass and a high-mass subsample, we find the high-mass subsample to show no significant mass bias while for the low-mass subsample, there is a bias towards overestimated X-ray masses at the ∼2σ level for some mass proxies. The overall scatter in the mass-mass scaling relations is surprisingly low. Investigating possible causes, we find that neither the greater range in WL than in X-ray masses nor the small scatter can be traced back to the parameter settings in the WL analysis. Conclusions. We do not find evidence for a strong (∼40%) underestimate in the X-ray masses, as suggested to reconcile recent Planck cluster counts and cosmological constraints. For high-mass clusters, our measurements are consistent with other studies in the literature. The mass dependent bias, significant at ∼2σ, may hint at a physically different cluster population (less relaxed clusters with more substructure and mergers); or it may be due to small number statistics. Further studies of low-mass high-z lensing clusters will elucidate their mass scaling behaviour.

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The Einstein Observatory Extended Medium-Sensitivity Survey. I - X-ray data and analysis

Cited by 451 publications

References 0 publications

The Smallest Mass Ratio Young Star Spectroscopic Binaries

The Smallest Mass Ratio Young Star Spectroscopic Binaries

A Measurement of the Density Parameter Derived from the Evolution of Cluster X-Ray Temperatures

The 400d Galaxy Cluster Survey weak lensing programme

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