MSc

Metal Enrichment Mechanisms in Abell 3571

XMM Guest Observer Program AO1 – PI: Dupke

Temperature & Metal Abundance Distribution of the Hot Gas within Abell 3571

Chandra Guest Observer Program AO4 - PI: Jimmy Irwin

Abell 3571 is the brightest of the hot cooling flow clusters that lie in a direction of low Galactic column. Also, it is he 6th brightest galaxy cluster overall, and the only cluster of the brightest 20 not yet observed with Chandra. Previous analyses of A3571 showed that this cluster exhibits a rich phenomenology, among them an apparent cooling flow and a central abundance enhancement, apparently associated with SN Ia ejecta dominance, as well as an apparent soft X-ray excess. We propose to analyze the abundance, temperature, and small scale structure of the central cooler region. This observation will be nicely complemented by an XMM-Newton observation of this cluster already approved for observation.

MSc-PhD (com inclusao de outros grupos (fosseis, normais) para Energetica do Gas Intergalatico em grupos de galaxias)

Galactic Winds and Intragroup Medium Energetics

XMM Guest Observer Program AO2 – PI: Dupke

Galaxy groups are the most common bound galaxy systems, and unlike clusters, the metal enrichment of their environments can be heavily dominated by galactic winds. The potential well of groups is too shallow to hold protogalactic winds, so that intragroup medium (IGM) should be mostly enriched by secondary SN Ia winds.

This enrichment history should be evident in the relative metal abundance ratios (Si/Fe,

Si/S, etc.) The proposal is to measure the enrichment properties in typical galaxy groups to determine the IGM contamination from SN Ia & II and study in detail SNIa wind energetics, testing whether SN II winds escaped completely from the Hickson Compact Groups or if they were trapped, by massive Dark Matter halos and also whether group infall into clusters can cause the SNIa dominance recently observed in the outskirts of rich clusters.

MSc-PhD (com aumento de cobertura (amostra ou banda de observacao ou teoria) para Movimento de Bojo no Meio-Intra-Aglomerado)

ICM Velocity Tomography in Abell 576 With XMM-NEWTON

XMM Guest Observer Program AO3 – PI: Dupke

Velocity Tomography of the Intracluster Gas with XMM XMM Guest Observer Program AO6 - PI: Dupke

We have recently found significant bulk velocities on the order of >2000 km/s in the ICM of Abell 576, as a result of a systematic search for ICM bulk motions in the ASCA archive. Such high gas velocities have a profound impact on our understanding of formation and evolution of clusters as well as in determining fundamental physical characteristics such as ICM mass and energetics. Therefore, independent confirmation of this discovery is crucial. XMM provides a unique opportunity to corroborate and improve such measurements due to the excellent gain stability of EPIC-MOS, which allows us to tailor the observation specifically for velocity studies. This will provide an enormous improvement over previous satellites allowing us to measure gas velocity differences of ~ 400km/s.

PhD- MSc (casos isolados significantes)

Determining the Temperature Profile for Clusters of Galaxies Once and For All

XMM Guest Observer Program AO3 - PI: Jimmy Irwin

Large Scale Intracluster Gas Properties of the Brightest Galaxy Cluster XMM Guest Observer Program AO4 - PI: Dupke

Large Scale ICM Properties of Perseus II - Correcting for Anisotropies XMM Guest Observer Program AO5 - PI: Dupke

Large Scale ICM Properties of the Centaurus Cluster XMM Guest Observer Program AO6 - PI: Dupke

Nearby galaxy clusters present a unique opportunity to study the spatial variation of the physical properties of the ICM and they also provide us with templates to test the biases introduced by simplifications assumed in the analysis of more distant clusters. Perseus, Centaurus, Coma, A1795, A496, stand out as the optimal choice for such an analysis, due to its brightness, proximity, and ubiquitous physical characteristics. We propose to completely map SN Type enrichment, gas bulk velocities, and other physical parameters up to ~0.3-0.4 of its virial radius. This analysis will address several current issues, such as the excess SN Ia pollution in the outer cluster regions and the claimed presence of velocity gradients in the ICM.

MSc-PhD (se aprovados dados de amostra maior com HST)

A Search for the Missing Baryons in Nearby Cosmic Filaments II - Sources of Bias

HST Guest Observer Program Cycle 14 – PI: Dupke

Local Missing Baryons in the Cosmic Web

FUSE Guest Observer Program Cycle 5 – PI: Dupke

A Search for the Missing Baryons in Nearby Cosmic Filaments

HST Guest Observer Program Cycle 12 – PI: Dupke

Stars and other detected gaseous phases in the local universe account for only about 20-50% of the baryonic mass as derived from Big-bang nucleosynthesis and 
quasar absorption line studies at high redshifts. Simulations predict that these baryons in the local universe are in a moderately hot phase, 105–107 K, largely
 in the form of giant cosmic filaments that connect the denser virialized clusters of galaxies. Since they are tenuous and have low overdensities these “missing” 
baryons evade detectability and are missing from census of the baryonic content of the local universe. They, however, can be detected through absorption lines 
hey produce in the spectra of background AGNs. These missing baryons are predicted to be in a warm-hot low density phase, largely in the giant cosmic filaments
 that connect the denser virialized clusters and groups of galaxies. The highest covering fraction of such filaments occurs in superclusters of galaxies, and observations 
of AGNs behind known superclusters show multiple LyAlpha absorption systems at the supercluster redshift. This project aims at determining absoption systems in the
 line of sight of cosmic filaments that connect galaxy clusters in the superclusters taken from the supercluster catalog (z<0.12) of Einasto et al. (1997). 

MSc-PhD (com aumento da amostra e limites cosmologicos)

Direct Observations of Dark Matter from a Second Bullet: The Spectacular Abell 2744 HST Guest Observer Program AO17 - PI: Dupke
Vigorous cluster mergers provide a unique opportunity to directly "see" dark matter and to probe its properties through the analysis of the segregation of the baryonic and non-baryonic components. This is accomplished through detailed comparison of the mass distributions as traced by X-ray emitting gas and by gravitational lensing. This condition is rare and so far only one cluster has met these requirements, the so-called "bullet" cluster, producing exciting results and placing constraints to the properties of dark matter.

These constraints have a broad impact on models for formation of structure and on galaxy evolution. This multi-wavelength analysis has the potential confront alternative gravity models such as MOND. Therefore, it is crucial to find new “bullet clusters” to corroborate and improve previous measurements. This is the most direct way to constrain dark matter properties and A2744 is ideal for corroborating this study since it maximizes all the requirements for this analysis. Here, we propose to carry out such analysis through combined ACS and Chandra observations of the cluster merger Abell 2744.

MSc

Cold Fronts in Hot Clusters

XMM Guest Observer Program AO6 – PI: Jimmy Irwin

Large Scale Enrichment Mechanisms & Constraints on Cold Front Models in A496
Suzaku Guest Observer Program AO2 - PI: Dupke

A496 is a "normal" nearby cluster that has been the test bed for metal enrichment models in clusters and, more recently, of different mechanisms to generate cold fronts. Suzaku’s excellent spectral resolution, low background and high effective area, combined with the moderate temperatures of this cluster allows us to probe, with two short exposures, into the large scale metal enrichment processes through determination of elemental abundance ratios out to half the virial radius for the first time.

MSc-PhD (desenvolvimentos futures com XMM data)

The Origin and Evolution of Fossil Groups

Chandra Guest Observer Program Cycle 10 – PI: Eli Rykoff

We propose snapshot observations of 5 optically selected fossil group candidates.

These observations will complete a sample of 15 intermediate-redshift fossil group candidates identified from the maxBCG optical cluster survey, 10 of which are scheduled via Chandra GTO time in Cycle 10. These observations will provide estimates of the diffuse X-ray flux for much deeper XMM-Newton follow-up, and they will also provide an estimate of the plasma temperature. They will also help constrain the predicted relation between BCG dominance and halo formation epoch. This snapshot project requires the spatial resolution of Chandra to separate diffuse emission from point source emission; when combined with the sensitivity of XMM-Newton follow-up, it will optimize the usage of these observatories.