Ruth A. Daly

Professor of Physics

Penn State University

Berks Campus 

P. O. Box 7009

Reading, PA 19610-6009

rdaly@psu.edu

610-396-6273 (phone)

610-396-6024 (fax)

 

Jan. 8, 1998 Press Release on the Acceleration of the Universe As indicated by Radio Galaxies

Jan. 4, 2010 Press Conference: "Black Hole Spins of Radio Sources"

Webcast of Talk "The Dark Energy Indicator: A Measure of Deviations of w from -1"

 Presented at the Conference "A Decade of Dark Energy," STSCI, May 2008

A Decade of Dark Energy: 1998 - 2008 Retrospective Presented at the 2008 UCLA Symposium "Dark Matter and Dark Energy in the Universe" R. A. Daly, 2009, in the proceedings of the 2008 UCLA conference "Dark Matter and Dark Energy in the Universe," AIP   

 

Selected Publications (Students Supervised by Daly are indicated by a Superscript S)        

The Relationship between Beam Power and Radio Power for Classical Double Radio Sources

R. A. Daly, T. B. SprinkleS, C. P. O'Dea, P. Kharb, & S. A. Baum, 2012, MNRAS, in press.

Estimates of Black Hole Spin Properties of 55 Sources

R. A. Daly, 2011, MNRAS, 414, 1253 - 1262.

A Detailed Study of the Lobes of Eleven Powerful Radio Galaxies

R. A. Daly, P. Kharb, C. P. O'Dea, S. A. Baum, M. P. MoryS, J. McKaneS, C. AltenderferS, & M. BeuryS  2010, ApJS, 187, 1-63.

Bounds on Black Hole Spins

R. A. Daly, 2009, ApJ, 696, L32-36.

Black Hole Spins of Radio Sources

R. A. Daly, 2009, ApJ, 691, L72-76.

Physical Properties of Very Powerful FRII Radio Galaxies

       C. P. O'Dea, R. A. Daly, K. A. FreemanS, P. Kharb, & S. Baum 2009, A&A, 494, 471-488.

Cosmological Studies with Radio Galaxies and Supernovae 

R. A. Daly, M. P. MoryS, C. P. O'Dea, P. Kharb, S. Baum, E. J. Guerra, & S. G. Djorgovski 2009,  ApJ, 691, 1058-1067.

Improved Constraints on the Acceleration History of the Universe and the Properties of the Dark Energy 

R. A. Daly, S. G. Djorgovski, K. A. FreemanS, M. P. MoryS, C. P. O'Dea, P. Kharb, & S. Baum,  2008, ApJ, 677, 1-11.

A Study of 13 Powerful Classical Double Radio Galaxies 

P. Kharb, C. P. O'Dea, S. A. Baum, R. A. Daly, M. P. MoryS, M. Donahue, & E. J. Guerra, 2008, ApJS, 174, 74-110.  

A Nearly Model-Independent Characterization of Dark Energy Properties as a Function of Redshift 

Ruth A. Daly & S. G. Djorgovski, 2006, NuPhS, 173, 19 – 23.   

Constraints on the Physical Parameters of the Dark Energy Using a Model-Independent Approach 

Ruth A. Daly &  S. G. Djorgovski, 2005, (arXiv:astro-ph/0512576)

Direct Determinations of the Redshift Behavior of the Pressure, Energy Density, and Equation of State of the Dark Energy and the Acceleration of the Universe  

Ruth A. Daly &  S. G. Djorgovski, 2005, International Journal of Modern Physics A, 20 (6): 1113-1120.

Radio Galaxies and the Acceleration of the Universe Beyond a Redshift of One

Ruth A. Daly, 2005, Keynote Invited Presentation, Advances in Space Research, Volume 35, Issue 1, Mars International Reference Atmosphere, Living with a Star and Fundamental Physics, eds. L. Zasova, J.T. Hoeksema, R.V. Duncan and T.J. Sumner, (Elsevier Ltd), 116-121. 

Direct Constraints on the Properties and Evolution of Dark Energy 

Ruth A. Daly &  S. G. Djorgovski, 2005, Invited Presentation, "Observing Dark Energy," ASP Conference Series,  Vol. 339, eds. Sidney C. Wolff and Tod R. Lauer (San Francisco: Astronomical Society of the Pacific), 117-127.

Comparison of Radio Observations and Numerical Simulations of the Radio Lobes of Cygnus A 

Joel C. Carvalho, Ruth A. Daly, Matthew P. MoryS, & Christopher P. O'Dea, 2005, the Astrophysical Journal (ApJ), 620, 126-144.

Direct Determination of the Kinematics of the Universe and Properties of the Dark Energy as Functions of Redshift 

Ruth A. Daly &  S. G. Djorgovski, 2004, ApJ, 612, 652-659.  

Cosmological Parameters and Quintessence from Radio Galaxies

Ruth A. Daly and Erick J. Guerra, 2003, Invited Presentation, “The Dark Universe: Matter, Energy, and Gravity,” eds. M. Livio & M. Fall (Cambridge: Cambridge University Press), 77-96.  

A Model-Independent Determination of the Expansion and Acceleration Rates of the Universe as a Function of Redshift and Constraints on Dark Energy

Ruth A. Daly &  S. G. Djorgovski 2003, ApJ, 597,  9-20.

Radio Galaxy Redshift-Angular Size Data Constraints on Dark Energy

Silviu Podariu, Ruth A. Daly, Matthew P. MoryS, and Bharat Ratra 2003, ApJ, 584, 577-579.  

Constraints on the Cluster Environments and Hot Spot Magnetic Field Strengths of the Radio Sources 3C 280 and 3C 254

Megan Donahue, Ruth A. Daly, and Donald J. Horner 2003, ApJ, 584, 643-656.  

Quintessence, Cosmology, and Fanaroff-Riley Type IIb Radio Galaxies

Ruth A. Daly, and Erick J. Guerra 2002, AJ, 124, 1831-1838.  

High-Redshift Radio Galaxies as a Cosmological Tool: Exploration of a Key Assumption and Comparison with Supernova Results

Ruth A. Daly, Matthew P. MoryS, and Erick J. Guerra 2002, Invited Presentation, in Cosmology and Elementary Particle Physics, ed. B. N. Kursunoglu, S. L. Mintz, and A. Perlmutter (New York: AIP), 87-94.  

Models Developed to Describe FRIIb and FRIIa Radio Sources

Ruth A. Daly, 2002, Invited Presentation, NewAR, 46, 47-60. 

Global Cosmological Parameters Determined Using Classical Double Radio Galaxies

Erick J. Guerra, Ruth A. Daly, & Lin Wan, 2000, ApJ, 544, 659-670.

Empirical Determinations of Key Physical Parameters Related to Classical Double Radio Sources  

Lin Wan, Ruth A. Daly, & Erick J. Guerra, 2000, ApJ, 544, 671-685.

A Detailed Investigation of Projection Effects Relevant to the Study of Powerful Classical Double Radio Sources

Lin WanS, Ruth A. Daly, 1998, ApJ, 499,614-634.

A Detailed Investigation of Radio Power Selection Effects Relevant to the Study of Classical Double Radio Sources

Lin WanS, Ruth A. Daly, 1998, ApJS, 115, 141-162.

Central Engines of Active Galactic Nuclei: Properites of Collimated Outflows and Applications for Cosmology

Erick J. GuerraS, Ruth A. Daly, 1998, ApJ, 493, 536-546.

Outflow Angles, Bulk Lorentz Factors, and Kinematics of Outflows from the Cores of Active Galactic Nuclei

Erick J, GuerraS, Ruth A. Daly, 1997, ApJ, 491, 483-500.

The Gaseous Environments of Powerful Extended Radio Sources

Greg F. WellmanS, Ruth A. Daly, Lin WanS, 1997, ApJ, 480, 96-114.

Radio Bridge Structure and Its Application to Estimate the Mach Number and Ambient Gas Temperature of Powerful Sources

Greg F. WellmanS, Ruth A. Daly, Lin WanS, 1997, ApJ, 480, 79-95.

Classical Double Radio Galaxies and Their Gaseous Environments

Lin WanS, Ruth A. Daly, 1996, ApJ, 467, 145-161.

Equipartition Doppler Factors for a Sample of Active Galactic Nuclei

Alberto GuijosaS, Ruth A. Daly, 1996, ApJ, 461, 600-608.

ROSAT HRI Observations of Four High-Redshift Clusters of Galaxies

Jennifer L. SokoloskiS, Ruth A. Daly, Simon J. Lilly, 1996, ApJ, 459, 142-146.

Powerful Extended Radio Sources as Tools to Estimate Ambient Gas Densities, Jet Luminosities, and Other Key Physical Parameters

Ruth A. Daly, 1995, ApJ, 454, 580-592.

Cosmology with Powerful Extended Radio Sources

Ruth A. Daly, 1994, ApJ, 426, 38-50.

The Connection Between Line Emission and Radio Power in Distant Radio Galaxies

Ruth A. Daly, ApJ, 1993, 406, 47-51.

Morphological Peculiarities of High-Redshift Radio Galaxies - The Role of Relativistic Electrons

Ruth A. Daly, 1992, ApJ, 399, 426-443.

Dark Matter and Brown Dwarfs - Prospects for the Direct Detection of a Brown Dwarf Halo

Ruth A. Daly, Gail C. McLaughlinS, 1992, ApJ, 390, 423-430.

Inverse Compton Scattering and the Alignments Observed in High-Redshift Radio Galaxies

Ruth A. Daly, 1992, ApJ, 386, L9-L12.

Constraints of Models for the High- and Low-Energy X-Ray Backgrounds

Ruth A. Daly, 1991, ApJ, 379, 37-51.

Spectral Distortions of the Microwave Background Radiation Resulting from the Damping of Pressure Waves

Ruth A. Daly, 1991, ApJ, 371, 14-28.

A Possible Origin of Galactic Magnetic Fields

Ruth A. Daly, Abraham Loeb, 1990, ApJ, 364, 451-455.

A Model to Explain the Correlation Between the Optical and Radio Properties of High-Redshift Galaxies

Ruth A. Daly, 1990, ApJ, 355, 416-426.

Masses of Rich Clusters of Galaxies as a Test of the Biased Cold Dark Matter Theory

P. J. E. Peebles, Ruth A. Daly, Roman Juszkiewics, 1989, ApJ, 347, 563-574.

The Gasdynamics of Compact Relativistic Jets

Ruth A. Daly, Alan P. Marscher, 1988, ApJ, 334, 539-551.

An Interpretation of the Excess Energy Density Observed on the Wien Side of the Microwave Background of Radiation

Ruth A. Daly, 1988, ApJ, 333, L1-L3.

Predictions in the Condensate Model of Evolution of Structures in the Universe

Ruth A. Daly, 1988, MNRAS, 232, 853-864.

Unstable Matter and the 1-0 MeV Gamma-Ray Background

Ruth A. Daly, 1988, ApJ, 324, L47-L50.

The Origin of the Diffuse X-Ray Background and the Formation of Galaxies and Voids

Ruth A. Daly, 1987, ApJ, 322, 20-33.