Browsing Ohio State University Research and Scholarship by Title
Now showing results 824-833 of 833
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X-Ray Absorption by the Low-Redshift Intergalactic Medium: A Numerical Study of the Λ Cold Dark Matter Model
Chen, Xuelei; Weinberg, David H.; Katz, Neal; Davé, Romeel ( 2003-09-01 )Using a hydrodynamic simulation of a cold dark matter universe with a cosmological constant, we investigate the "X-ray forest" absorption imprinted on the spectra of background quasars by the intervening intergalactic ... -
X-ray absorption via Kα resonance complexes in oxygen ions
Nahar, Sultana Nurun; Pradhan, Anil K.; Chen, Guo Xin; Delahaye, Franck; Oelgoetz, Justin ( 2003-06 )The Kα resonance complexes in oxygen ions OI–O VI are theoretically computed, and resonance oscillator strengths and wavelengths are presented. The highly resolved photoionization cross-sections, with relativistic fine ... -
X-Ray and Optical Variability in NGC 4051 and the Nature of Narrow-Line Seyfert 1 Galaxies
Peterson, B. M.; McHardy, I. M.; Wilkes, B. J.; Berlind, P.; Bertram, R.; Calkins, M.; Collier, S. J.; Huchra, J. P.; Mathur, S.; Papadakis, I.; Peters, J.; Pogge, R. W.; Romano, P.; Tokarz, S.; Uttley, P.; Vestergaard, M.; Wagner, R. M. ( 2000-10-10 )We report on the results of a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The rapid continuum variations observed in the X-ray spectra are not detected in ... -
XMM-Newton Observations of SDSS J143030.22 – 001115.1: An Unusually Flat-Spectrum Active Galactic Nucleus
Mathur, S.; Golowacz, E. C.; William, R.; Pogge, R.; Fields, D.; Grupe, D. ( 2009-12 )We present XMM-Newton observations of the type 1 active galactic nucleus (AGN) SDSS 1430 – 0011 (z = 0.1032). The low signal-to-noise ratio spectrum of this source obtained in a snap shot Chandra observation showed an ... -
XMM-Newton Observations of the Radio-Loud Broad Absorption Line Quasar FBQS J131213.5+231958
Mathur, Smita; Dai, Xinyu ( 2010-12 )We present XMM-Newton observations of the broad absorption line (BAL) quasar FBQS J131213.5+231958. The X-ray spectrum of the source can be well described by an absorbed power-law model in which the absorber is either ... -
The z = 5.8 Quasar SDSSp J1044−0125: A Peek at Quasar Evolution?
Mathur, Smita ( 2001-10 )The newly discovered z = 5.8 quasar SDSSp J104433.04-012502.2 was recently detected in X-rays and found to be extremely X-ray weak. Here we present the hardness ratio analysis of the XMM-Newton observation. We consider ... -
The Zero Point of Extinction toward Baade's Window from K Giants
Gould, Andrew; Popowski, Piotr; Terndrup, Donald M. ( 1998-01-10 )We measure the zero point of the Stanek extinction map by comparing the observed (V - K) colors of 206 K giant stars with their intrinsic (V - K)_0 colors as derived from their Hβ indices. We find that the zero point of ... -
Zinc in Attention-Deficit/Hyperactivity Disorder
Arnold, L. Eugene; DiSilvestro, Robert A. ( 2005 )Objective: The aim of this study was to review the published evidence for a role of zinc nutrition in attentiondeficit/ hyperactivity disorder (ADHD). Method: A computer literature search was supplemented by the authors’ ... -
The κB transcriptional enhancer motif and signal sequences of V(D)J recombination are targets for the zinc finger protein HIVEP3/KRC: a site selection amplification binding study
Allen, Carl E.; Mak, Chi-ho; Wu, Lai-Chu ( 2002-08-22 )Background: The ZAS family is composed of proteins that regulate transcription via specific gene regulatory elements. The amino-DNA binding domain (ZAS-N) and the carboxyl-DNA binding domain (ZAS-C) of a representative ... -
Ω_B and Ω_0 from MACHOs and Local Group Dynamics
Steigman, G.; Tkachev, I. ( 1999-09-10 )We obtain restrictions on the universal baryon fraction, f_B ≡ Ω_B/Ω_0, by assuming that the observed microlensing events toward the Large Magellanic Cloud are due to baryonic MACHOs in the halo of the Galaxy and by ...