Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters (2009)
Cavagnolo, Kenneth W., Donahue, Megan, Voit, G. Mark, Sun, Ming
We present radial entropy profiles of the intracluster medium (ICM) for a collection of 239 clusters taken from the Chandra X-ray Observatory's Data Archive. Entropy is of great interest because it...
Substructure and Scatter in the Mass-Temperature Relations of Simulated Clusters (2008)
Ventimiglia, David A., Voit, G. Mark, Donahue, Megan, Ameglio, S.
Galaxy clusters exhibit regular scaling relations among their bulk properties. These relations establish vital links between halo mass and cluster observables. Precision cosmology studies that depend...
An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores of Galaxy Clusters (2008)
Cavagnolo, Kenneth W., Donahue, Megan, Voit, G. Mark, Sun, Ming
Our Chandra X-ray Observatory archival study of intracluster entropy in a sample of 222 galaxy clusters shows that H-alpha and radio emission from the brightest cluster galaxy are much more...
Bandpass Dependence of X-ray Temperatures in Galaxy Clusters (2008)
Cavagnolo, Kenneth W., Donahue, Megan, Voit, G. Mark, Sun, Ming
We explore the band dependence of the inferred X-ray temperature of the intracluster medium (ICM) for 192 well-observed galaxy clusters selected from the Chandra Data Archive. If the hot ICM is...
Infrared Emission from the Nearby Cool Core Cluster Abell 2597 (2007)
Donahue, Megan, Jordan, Andres, Baum, Stefi A., Cote, Patrick, Ferrarese, Laura, Goudfrooij, Paul, ...
We observed the brightest central galaxy (BCG) in the nearby (z=0.0821) cool core galaxy cluster Abell 2597 with the IRAC and MIPS instruments on board the Spitzer Space Telescope. The BCG was...
Donahue, Megan, Sun, Ming, O'Dea, Christopher P., Voit, G. Mark, Cavagnolo, Kenneth W.
We present deep emission-line imaging taken with the SOAR Optical Imaging Camera of the brightest cluster galaxy (BCG) in the nearby (z=0.035) X-ray cluster 2A0335+096. We analyze long-slit optical...
Donahue, Megan, Ming, Sun, O'Dea, Christopher, Voit, G. Mark, Cavagnolo, Kenneth
Also archived in: arXiv:0705.1659 v1 May 11 2007
Modelling Shock Heating in Cluster Mergers: I. Moving Beyond the Spherical Accretion Model (2007)
McCarthy, Ian G., Bower, Richard G., Balogh, Michael L., Voit, G. Mark, Pearce, Frazer R., Theuns, Tom, ...
(Abridged) The thermal history of the intracluster medium (ICM) is complex. Heat input from cluster mergers, AGN, and galaxy winds offsets and may even halt the cooling of the ICM. Consequently, the...
Entropy generation in merging galaxy clusters (2007)
Balogh, Michael, McCarthy, Ian, Bower, Richard, Voit, G. Mark
In McCarthy et al. (2007, astro-ph/0701335) we present an analysis of entropy generation during cluster mergers, using SPH simulations. This conference proceeding contribution summarizes some of the...
Balogh, Michael L., Babul, Arif, Voit, G. Mark, McCarthy, Ian G., Jones, Laurence R., Lewis, Geraint F., ...
(Abridged) We revisit the scaling relationships between the dark matter mass and observed X-ray luminosity and temperature of galaxy clusters and groups in the local Universe. Specifically, we...
Entropy Profiles in the Cores of Cooling Flow Clusters of Galaxies (2005)
Donahue, Megan, Horner, Donald J., Cavagnolo, Kenneth W., Voit, G. Mark
The X-ray properties of a relaxed cluster of galaxies are determined primarily by its gravitational potential well and the entropy distribution of its intracluster gas. That entropy distribution...
The baseline intracluster entropy profile from gravitational structure formation (2005)
Voit, G. Mark, Kay, Scott T., Bryan, Greg L.
The radial entropy profile of the hot gas in clusters of galaxies tends to follow a power law in radius outside of the cluster core. Here we present a simple formula giving both the normalization and...
An Observationally Motivated Framework for AGN Heating of Cluster Cores (2005)
The cooling-flow problem is a long-standing puzzle that has received considerable recent attention, in part because the mechanism that quenches cooling flows in galaxy clusters is likely to be the...
Two clusters of galaxies with radio-quiet cooling cores (2005)
Donahue, Megan, Voit, G. Mark, O’Dea, Christopher, Baum, Stefi, Sparks, William
Also archived in: arXiv: astro-ph/0508587 v1 26 Aug 2005
Two clusters of galaxies with radio-quiet cooling cores (2005)
Donahue, Megan, Voit, G. Mark, O’Dea, Christopher, Baum, Stefi, Sparks, William
Also archived in: arXiv: astro-ph/0508587 v1 26 Aug 2005
Two Clusters with Radio-quiet Cooling Cores (2005)
Donahue, Megan, Voit, G. Mark, O'Dea, Christopher P., Baum, Stefi A., Sparks, William B.
Radio lobes inflated by active galactic nuclei at the centers of clusters are a promising candidate for halting condensation in clusters with short central cooling times because they are common in...
Cooling and Clusters: When Is Heating Needed? (2005)
There are (at least) two unsolved problems concerning the current state of the thermal gas in clusters of galaxies. The first is identifying the source of the heating which offsets cooling in the...
Tracing cosmic evolution with clusters of galaxies (2004)
The most successful cosmological models to date envision structure formation as a hierarchical process in which gravity is constantly drawing lumps of matter together to form increasingly larger...
Signatures of Galaxy Formation in the Intracluster Medium (2003)
Voit, G. Mark, Ponman, Trevor J.
The intergalactic gas in groups and clusters of galaxies bears the indelible stamp of galaxy formation. We present a comparison between observations and simple theoretical models indicating that...
Cool Gas in Clusters of Galaxies (2003)
Early X-ray observations suggested that the intracluster medium cools and condenses at the centers of clusters, leading to a cooling flow of plasma in the cluster core. The increased incidence of...
On the Origin of Intracluster Entropy (2003)
Voit, G. Mark, Balogh, Michael L., Bower, Richard G., Lacey, Cedric G., Bryan, Greg L.
The entropy distribution of the intracluster medium and the shape of its confining potential well completely determine the X-ray properties of a relaxed cluster of galaxies, motivating us to explore...
Modified-Entropy Models for the Intracluster Medium (2002)
Voit, G. Mark, Bryan, Greg L., Balogh, Michael L., Bower, Richard G.
We present a set of cluster models that link the present-day properties of clusters to the processes that govern galaxy formation. These models treat the entropy distribution of the intracluster...
Donahue, Megan, Scharf, Caleb, Mack, Jennifer, Lee, Paul, Postman, Marc, Rosati, Piero, ...
We present and analyze the optical and X-ray catalogs of moderate-redshift cluster candidates from the ROSAT Optical X-ray Survey, or ROXS. The survey covers 4.8 square degrees (23 ROSAT PSPC...
Donahue, Megan, Mack, Jennifer, Scharf, Caleb, Lee, Paul, Postman, Marc, Rosati, Piero, ...
We present a comparison of X-ray and optical luminosities and luminosity functions of cluster candidates from a joint optical/X-ray survey, the ROSAT Optical X-Ray Survey. Completely independent...
Discovery of ghost cavities in Abell 2597's X-ray atmosphere (2001)
McNamara, Brian, Wise, Michael, Nulsen, Paul, David, Laurence, Carilli, Chris, Sarazin, Craig, ...
Also archived in: arXiv: astro-ph/0110554 v1 25 Oct 2001
Regulation of the X-ray luminosity of clusters of galaxies by cooling and supernova feedback (2001)
Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of the cluster, and the baryons...
On the Distribution of X-ray Surface Brightness from Diffuse Gas (2001)
Hot intergalactic gas in clusters, groups, and filaments emanates a continuous background of 0.5-2.0 keV X-rays that ought to be detectable with the new generation of X-ray observatories. Here we...
The X-ray surface brightness distribution from diffuse gas (2001)
We use simulations to predict the X-ray surface brightness distribution arising from hot, cosmologically distributed diffuse gas. The distribution is computed for two bands: 0.5-2 keV and 0.1-0.4...
Confusion of Diffuse Objects in the X-ray Sky (2000)
Voit, G. Mark, Evrard, August E., Bryan, Greg L.
Most of the baryons in the present-day universe are thought to reside in intergalactic space at temperatures of 10^5-10^7 K. X-ray emission from these baryons contributes a modest (~10%) fraction of...
HST Observations of Vibrationally-Excited Molecular Hydrogen in Cluster Cooling Flow Nebulae (2000)
Donahue, Megan, Mack, Jennifer, Voit, G. Mark, Sparks, William, Elston, Richard, Maloney, Philip R.
We report new HST NICMOS and WFPC2 imaging of emission-line nebulae in the central galaxies of 3 clusters of galaxies purported to host massive cooling flows, NGC1275, A2597, and PKS0745. The...
Evidence for X-ray emission from a large-scale filament of galaxies ? (1999)
Scharf, Caleb, Donahue, Megan, Voit, G. Mark, Rosati, Piero, Postman, Marc
Cosmological simulations predict that a large fraction of the baryonic mass of the Universe exists as 10^5-10^7 K diffuse, X-ray emitting gas, tracing low density filament and sheet-like structures...
The Extended blue continuum and line emission around the Central Radio Galaxy in Abell 2597 (1999)
Koekemoer, Anton, O'Dea, Christopher, Sarazin, Craig, McNamara, Brian, Donahue, Megan, Voit, G. Mark, ...
Also archived in: arXiv: astro-ph/9906335 v1 21 Jun 1999
The extended blue continuum and line emission around the Central Radio Galaxy in Abell 2597 (1999)
Koekemoer, Anton, O'Dea, Christopher, Sarazin, Craig, McNamara, Brian, Donahue, Megan, Voit, G. Mark, ...
Also archived in: arXiv: astro-ph/9906335 v1 21 Jun 1999
Omega-Matter from the Temperature-Redshift Distribution of EMSS Clusters of Galaxies (1999)
We constrain Omega_m through a maximum likelihood analysis of temperatures and redshifts of the high-redshift clusters from the EMSS. We simultaneously fit the low-redshift Markevitch (1998) sample...
The Second Most Distant Cluster of Galaxies in the EMSS (1999)
Donahue, Megan, Voit, G. Mark, Scharf, Caleb A., Gioia, Isabella M., Mullis, Christopher R., Hughes, John P., ...
We report on our ASCA, Keck, and ROSAT observations of MS1137.5+6625, the second most distant cluster of galaxies in the Einstein Extended Medium Sensitivity Survey (EMSS), at redshift 0.78. We now...
On the Evolution of the Temperature-Viral Mass Relation for Clusters of Galaxies (1998)
X-ray temperature measurements of clusters of galaxies are now reaching to redshifts high enough to constrain Omega_0. A redshift-dependent relation that maps these X-ray temperatures to the virial...
On Nulling Interferometers and the Line-Emitting Regions of AGNs (1997)
The nulling interferometers proposed to study planets around other stars are generally well suited for studying small-scale structures surrounding other bright pointlike objects such as the nuclei of...
A Very Hot, High Redshift Cluster of Galaxies: More Trouble for Omega_0 = 1 (1997)
Donahue, Megan, Voit, G. Mark, Gioia, Isabella M., Luppino, Gerry, Hughes, John P., Stocke, John T.
We have observed the most distant (z=0.829) cluster of galaxies in the Einstein Extended Medium Sensitivity Survey, with the ASCA and ROSAT satellites. We find an X-ray temperature of 12.3 +3.1/-2.2...
Cosmological Blastwaves and the Intergalactic Medium (1996)
Winds from protogalactic starbursts and quasars can drive shocks that heat, ionize, and enrich the intergalactic medium. The Sedov-Taylor solution for point-like explosions adequately describes these...