Self calibration of photometric redshift scatter in weak lensing surveys (2009)
Zhang, Pengjie, Pen, Ue-Li, Bernstein, Gary
Photo-z errors, especially catastrophic errors, are a major uncertainty for precision weak lensing cosmology. We find that the shear-(galaxy number) density and density-density cross correlation...
He, Jian-Hua, Wang, Bin, Zhang, Pengjie
Dark energy interacting with dark matter is a promising model to solve the cosmic coincidence problem. We study the signature of such interaction on large scale cosmic microwave background (CMB)...
The thermal SZ tomography (2009)
Shao, Jiawei, Zhang, Pengjie, Lin, Weipeng, Jing, Yipeng
The thermal Sunyaev-Zel'dovich (tSZ) effect directly measures the thermal pressure of free electrons integrated along the line of sight and thus contains valuable information on the thermal history...
The existence of non-random galaxy intrinsic ellipticity severely challenges precision cosmic shear measurement. We propose to self calibrate the induced gravitational shear-galaxy intrinsic...
Wang, Xin, Chen, Xuelei, Zheng, Zheng, Wu, Fengquan, Zhang, Pengjie, Zhao, Yongheng
The Large Area Multi-Object Spectroscopic Telescope (LAMOST) is a dedicated spectroscopic survey telescope being built in China, with an effective aperture of 4 meters and equiped with 4000 fibers....
Weighing the spatial and temporal fluctuations of the dark universe (2008)
Zhang, Pengjie, Bean, Rachel, Liguori, Michele, Dodelson, Scott
A generic prediction of the standard cosmology, based on general relativity (GR), dark matter and the cosmological constant (and more generally, smooth dark energy), is that, the two gravitational...
A new method of measuring the cluster peculiar velocity power spectrum (2008)
Zhang, Pengjie, Feldman, Hume A., Juszkiewicz, Roman, Stebbins, Albert
We propose to use spatial correlations of the kinetic Sunyaev-Zeldovich (KSZ) flux as an estimator of the peculiar velocity power spectrum. In contrast with conventional techniques, our new method...
Baryon acoustic oscillation (BAO) is a powerful probe on the expansion of the universe, shedding light on elusive dark energy and gravity at cosmological scales. BAO measurements through biased...
Free electrons deplete photons from type Ia supernovae through the (inverse) Compton scattering. This Compton dimming increases with redshift and reaches 0.004 mag at $z=1$ and 0.01 mag at $z=2$....
Type Ia supernovae as speed sensors at intermediate redshifts (2007)
The application of large scale peculiar velocity (LSPV), as a crucial probe of dark matter, dark energy and gravity, is severely limited by measurement obstacles. We show that fluctuations in type Ia...
Observational Tests of Modified Gravity (2007)
Jain, Bhuvnesh, Zhang, Pengjie
Modified gravity theories have richer observational consequences for large-scale structure than conventional dark energy models, in that different observables are not described by a single growth...
Impact of astrophysical processes on the gamma-ray background from dark matter annihilations (2007)
Ahn, Eun-Joo, Bertone, Gianfranco, Merritt, David, Zhang, Pengjie
Also archived in: arXiv:astro-ph/0703236 v2 Jul 31 2007
A discriminating probe of gravity at cosmological scales (2007)
Zhang, Pengjie, Liguori, Michele, Bean, Rachel, Dodelson, Scott
The standard cosmological model is based on general relativity and includes dark matter and dark energy. An important prediction of this model is a fixed relationship between the gravitational...
Impact of astrophysical processes on the gamma-ray background from dark matter annihilations (2007)
Ahn, Eun-Joo, Bertone, Gianfranco, Merritt, David, Zhang, Pengjie
We study the impact of astrophysical processes on the gamma-ray background produced by the annihilation of dark matter particles in cosmological halos, with particular attention to the consequences...
The probability distribution function of the SZ power spectrum: an analytical approach (2007)
Zhang, Pengjie, Sheth, Ravi K.
The Sunyaev Zel'dovich (SZ) signal is highly non-Gaussian, so the SZ power spectrum (along with the mean $y$ parameter) does not provide a complete description of the SZ effect. Therefore, SZ-based...
The behavior of $f(R)$ gravity in the solar system, galaxies and clusters (2007)
For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and...
Detecting First Star Lyman-$\alpha$ Spheres through Gravitational Telescopes (2007)
Li, Guoliang, Zhang, Pengjie, Chen, Xuelei
Lyman-$\alpha$ spheres, i.e. regions around the first stars which are illuminated by Lyman-$\alpha$ photons and show 21cm absorption feature against the CMB, are smoking guns at the dawn of the...
Lensing of 21cm Absorption "Halos" of $z\sim$20-30 First Galaxies (2006)
Zhang, Pengjie, Zheng, Zheng, Cen, Renyue
Extended 21cm absorption regions (dubbed ``21cm absorption halos'') around first galaxies at $z\sim 30$ are likely the first distinctive structures accessible to radio observations. Though the radio...
Cosmic Dust Induced Flux Fluctuations: Bad and Good Aspects (2006)
Zhang, Pengjie, Corasaniti, Pier Stefano
Cosmic dust extinction alters the flux of type Ia supernovae. Inhomogeneities in the dust distribution induce correlated fluctuations of the SN fluxes. We find that such correlation can be up to 60%...
The influence of baryons on the clustering of matter and weak-lensing surveys (2006)
Jing, Y. P., Zhang, Pengjie, Lin, W. P., Gao, L., Springel, V.
Isolating the decay rate of cosmological gravitational potential (2005)
The decay rate of cosmological gravitational potential measures the deviation from Einstein-de Sitter universe and can put strong constraints on the nature of dark energy and gravity. Usual method to...
The influence of baryons on the clustering of matter and weak lensing surveys (2005)
Jing, Y. P., Zhang, Pengjie, Lin, W. P., Gao, L., Springel, V.
Future weak lensing measurements of cosmic shear will reach such high accuracy that second order effects in weak lensing modeling, like the influence of baryons on structure formation, become...
Testing Gravity Against Early Time Integrated Sachs-Wolfe Effect (2005)
A generic prediction of general relativity is that the cosmological linear density growth factor $D$ is scale independent. But in general, modified gravities do not preserve this signature. A scale...
Mapping dark matter with cosmic magnification (2005)
We develop a new tool to generate statistically precise dark matter maps from the cosmic magnification of galaxies with distance estimates. We show how to overcome the intrinsic clustering problem...
Precision measurement of cosmic magnification from 21 cm emitting galaxies (2005)
We show how precision lensing measurements can be obtained through the lensing magnification effect in high redshift 21cm emission from galaxies. Normally, cosmic magnification measurements have been...
Strigari, Louis E., Beacom, John F., Walker, Terry P., Zhang, Pengjie
We constrain the Cosmic Star Formation Rate (CSFR) by requiring that massive stars produce the observed UV, optical, and IR light while at the same time not overproduce the Diffuse Supernova Neutrino...
The Weak Lensing Bispectrum (2005)
Dodelson, Scott, Zhang, Pengjie
Weak gravitational lensing of background galaxies offers an excellent opportunity to study the intervening distribution of matter. While much attention to date has focused on the two-point function...
A new method of measuring the peculiar velocity power spectrum (2004)
Zhang, Pengjie, Stebbins, Albert, Juszkiewicz, Roman, Feldman, Hume
We show that by directly correlating the cluster kinetic Sunyaev Zeldovich (KSZ) flux, the cluster peculiar velocity power spectrum can be measured to $\sim 10%$ accuracy by future large sky coverage...
The intergalactic medium temperature and Compton y parameter (2004)
Zhang, Pengjie, Pen, Ue-Li, Trac, Hy
(Abridged) The precision modeling of the thermal Sunyaev Zeldovich (SZ) effect and future high accuracy measurements will provide a powerful way to constrain the thermal history of the universe. In...
Angular Correlations of the MeV Cosmic Gamma Ray Background (2004)
Zhang, Pengjie, Beacom, John F.
The measured cosmic gamma ray background (CGB) spectrum at MeV energies is in reasonable agreement with the predicted contribution from type Ia supernovae (SNIa). But the characteristic features in...
The effect of cluster magnetic field on the Sunyaev Zeldovich power spectrum (2003)
Precision measurements of the Sunyaev Zeldovich (SZ) effect in upcoming blank sky surveys require theoretical understanding of all physical processes with $\ga 10%$ effects on the SZ power spectrum....
Cross correlations of the cosmic infrared background (2003)
The cosmic infrared background (CIB) is a sensitive measure of the star formation history. But this background is overwhelmed by foregrounds, which bias the CIB mean flux and auto correlation...
Optimal Weak Lensing Skewness Measurements (2003)
Zhang, Tong-Jie, Pen, Ue-Li, Zhang, Pengjie, Dubinski, John
Weak lensing measurements are entering a precision era to statistically map the distribution of matter in the universe. The most common measurement has been of the variance of the projected surface...
Zhang, Pengjie, Pen, Ue-Li, Trac, Hy
The kinetic SZ effect, which is the dominant CMB source at arc-minute scales and $\nu \sim 217$ Ghz, probes the ionized gas peculiar momentum up to the epoch of reionization and is a sensitive...
Detection of dark matter Skewness in the VIRMOS-DESCART survey: Implications for \Omega_0 (2003)
Pen, Ue-Li, Zhang, Tongjie, Van Waerbeke, Ludovic, Mellier, Yannick, Zhang, Pengjie, Dubinski, John
Weak gravitational lensing provides a direct statistical measure of the dark matter distribution. The variance is easiest to measure, which constrains the degenerate product \sigma_8\Omega^0.6. The...
Hydrodynamical Simulations of the IGM at High Mach Numbers (2002)
Trac, Hy, Zhang, Pengjie, Pen, Ue-Li
We present a new approach to doing Eulerian computational fluid dynamics that is designed to work at high Mach numbers encountered in hydrodynamical simulations of the IGM. In conventional Eulerian...
We explore the intergalactic medium (IGM) as a potential source of the unresolved soft X-ray background (XRB) and the feasibility to extract the IGM state and evolution from XRB observations. We...
The Sunyaev Zel'dovich effect: simulation and observation (2002)
Zhang, Pengjie, Pen, Ue-Li, Wang, Benjamin
The Sunyaev Zel'dovich effect (SZ effect) is a complete probe of ionized baryons, the majority of which are likely hiding in the intergalactic medium. We ran a $512^3$ $\Lambda$CDM simulation using a...
Deprojecting Sunyaev-Zeldovich statistics (2000)
We apply the hierarchical clustering model and non-linear perturbation theory to the cosmological density and temperature fields. This allows us to calculate the intergalactic gas pressure power...
Friedmann Equation and Stability of Inflationary Higher Derivative Gravity (1999)
Kao, W. F., Pen, Ue-Li, Zhang, Pengjie
Stability analysis on the De Sitter universe in pure gravity theory is known to be useful in many aspects. We first show how to complete the proof of an earlier argument based on a redundant field...