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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Early-Type Galaxies In The Chandra Cosmos Survey, F. Civano, G. Fabbiano, S. Pellegrini, D.-W. Kim
Early-Type Galaxies In The Chandra Cosmos Survey, F. Civano, G. Fabbiano, S. Pellegrini, D.-W. Kim
Dartmouth Scholarship
We study a sample of 69 X-ray detected early-type galaxies (ETGs), selected from the Chandra COSMOS survey, to explore the relation between the X-ray luminosity of hot gaseous halos (L X, gas) and the integrated stellar luminosity (LK ) of the galaxies, in a range of redshift extending out to z = 1.5. In the local universe, a tight, steep relationship has been established between these two quantities, suggesting the presence of largely virialized halos in X-ray luminous systems. We use well-established relations from the study of local universe ETGs, together with the expected evolution …
The Xmm-Newton Spectrum Of A Candidate Recoiling Supermassive Black Hole: An Elusive Inverted P-Cygni Profile, G. Lanzuisi, F. Civano, S. Marchesi, A. Comastri
The Xmm-Newton Spectrum Of A Candidate Recoiling Supermassive Black Hole: An Elusive Inverted P-Cygni Profile, G. Lanzuisi, F. Civano, S. Marchesi, A. Comastri
Dartmouth Scholarship
We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black hole (SMBH) showing also an inverted P-Cygni profile in the X-ray spectra at ~6 keV (rest) with an iron emission line plus a redshifted absorption line (detected at 3σ in previous XMM-Newton and Chandra observations). Detailed analysis of the absorption line suggested the presence of ionized material flowing into the black hole at high velocity. In the …
The Chandra X-Ray Point-Source Catalog In The Deep2 Galaxy Redshift Survey Fields, A. D. Goulding, W. R. Forman, R. C. Hickox, C. Jones
The Chandra X-Ray Point-Source Catalog In The Deep2 Galaxy Redshift Survey Fields, A. D. Goulding, W. R. Forman, R. C. Hickox, C. Jones
Dartmouth Scholarship
We present the X-ray point-source catalog produced from the Chandra Advanced CCD Imaging Spectrometer (ACIS-I) observations of the combined \sim3.2 deg2 DEEP2 (XDEEP2) survey fields, which consist of four ~0.7-1.1 deg2 fields. The combined total exposures across all four XDEEP2 fields range from ~10ks-1.1Ms. We detect X-ray point-sources in both the individual ACIS-I observations and the overlapping regions in the merged (stacked) images. We find a total of 2976 unique X-ray sources within the survey area with an expected false-source contamination of ~30 sources (~1%). We present the combined logN-logS distribution of sources detected across the XDEEP2 survey fields and …
Effects Of Gravitational Slip On The Higher-Order Moments Of The Matter Distribution, Scott F. Daniel
Effects Of Gravitational Slip On The Higher-Order Moments Of The Matter Distribution, Scott F. Daniel
Dartmouth Scholarship
Cosmological departures from general relativity offer a possible explanation for the cosmic acceleration. To linear order, these departures (quantified by the model-independent parameter ϖ, referred to as a “gravitational slip”) amplify or suppress the growth of structure in the universe relative to what we would expect to see from a general relativistic universe lately dominated by a cosmological constant. As structures collapse and become more dense, linear perturbation theory is an inadequate descriptor of their behavior, and one must extend calculations to nonlinear order. If the effects of gravitational slip extend to these higher orders, we might expect to see …
Large Scale Structure As A Probe Of Gravitational Slip, Scott F. Daniel, Robert R. Caldwell, Asantha Cooray, Alessandro Melchiorri
Large Scale Structure As A Probe Of Gravitational Slip, Scott F. Daniel, Robert R. Caldwell, Asantha Cooray, Alessandro Melchiorri
Dartmouth Scholarship
A new time-dependent, scale-independent parameter, ϖ, is employed in a phenomenological model of the deviation from general relativity in which the Newtonian and longitudinal gravitational potentials slip apart on cosmological scales as dark energy, assumed to be arising from a new theory of gravitation, appears to dominate the Universe. A comparison is presented between ϖ and other parametrized post-Friedmannian models in the literature. The effect of ϖ on the cosmic microwave background anisotropy spectrum, the growth of large-scale structure, the galaxy weak-lensing correlation function, and cross correlations of cosmic microwave background anisotropy with galaxy clustering are illustrated. Cosmological models with …
Sudden Gravitational Transition, Robert R. Caldwell, William Komp, Leonard Parker, Daniel A. T. Vanzella
Sudden Gravitational Transition, Robert R. Caldwell, William Komp, Leonard Parker, Daniel A. T. Vanzella
Dartmouth Scholarship
We investigate the properties of a cosmological scenario which undergoes a gravitational phase transition at late times. In this scenario, the Universe evolves according to general relativity in the standard, hot big bang picture until a redshift z≲1. Nonperturbative phenomena associated with a minimally-coupled scalar field catalyzes a transition, whereby an order parameter consisting of curvature quantities such as R2, RabRab, RabcdRabcd acquires a constant expectation value. The ensuing cosmic acceleration appears driven by a dark-energy component with an equation-of-state w<−1. We evaluate the constraints from type 1a supernovae, the cosmic microwave background, and other cosmological observations. We find that a range of models making a sharp transition to cosmic acceleration are consistent with observations.
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Dartmouth Scholarship
We present results of a statistical analysis of the SFI catalog of peculiar velocities, a recently completed survey of spiral field galaxies with I-band Tully-Fisher distances. The velocity field statistic utilized is the velocity correlation function, ψ1(r), originally introduced by Górski et al. The analysis is performed in redshift space so as to circumvent potential ambiguities connected with inhomogeneous Malmquist bias corrections. The results from the SFI sample are compared with linear-theory predictions for a class of cosmological models. We generate a large set of mock samples, extracted from N-body simulations, which are used …