The cosmological information of shear peaks: beyond the abundance

We study the cosmological information of weak lensing (WL) peaks, focusing on two other statistics besides their abundance: the stacked tangential-shear profiles and the peak-peak correlation function. We use a large ensemble of simulated WL maps with survey specifications relevant to future missions like Euclid and LSST, to explore the three peak probes. We find that the correlation function of peaks with high signal-to-noise (S/N) measured from fields of size 144 sq. deg. has a maximum of ~0.3 at an angular scale ~10 arcmin. For peaks with smaller S/N, the amplitude of the correlation function decreases, and its maximum occurs on smaller angular scales. We compare the peak observables measured with and without shape noise and find that for S/N~3 only ~5% of the peaks are due to large-scale structures, the rest being generated by shape noise. The covariance matrix of the probes is examined: the correlation function is only weakly covariant on scales < 30 arcmin, and slightly more on larger scales; the shear profiles are very correlated for theta > 2 arcmin, with a correlation coefficient as high as 0.7. Using the Fisher-matrix formalism, we compute the cosmological constraints for {Om_m, sig_8, w, n_s} considering each probe separately, as well as in combination. We find that the correlation function of peaks and shear profiles yield marginalized errors which are larger by a factor of 2-4 for {Om_m, sig_8} than the errors yielded by the peak abundance alone, while the errors for {w, n_s} are similar. By combining the three probes, the marginalized constraints are tightened by a factor of ~2 compared to the peak abundance alone, the least contributor to the error reduction being the correlation function. This work therefore recommends that future WL surveys use shear peaks beyond their abundance in order to constrain the cosmological model.Comment: 15 pages, 10 figures, submitted to MNRA

Nurses Alumni Association Bulletin, Fall 1999

1999-2000 Meeting Dates Calendar 2000 Annual Luncheon-Meeting Notice Fall Social Officers and Committee Chairs Bulletin Publication Committee The President\u27s Message Treasurer\u27s Report News About Our Graduates History of The Nurses Relief Fund Nurses Wear White Memories of My Nurse Training Days Scholarship Funds At Work Second Janet C. Hindson Award Rib Ticklers Happy Birthday Fiftieth Anniversary Resume Alumni Association Meetings Alumni Office News Committee Reports Bulletin Nominating Relief Fund Scholarship Social Development Luncheon Photos In Memoriam, Names of Deceased Graduates Class News Janet C. Hindson Memorial Award (How to Submit Names) Scholarship Fund Application Certification Reimbursement Application Relief Fund Application Pins, Transcripts, Class Address List, Change of Address Forms Campus Ma

Towards optimal estimation of the galaxy power spectrum

The galaxy power spectrum encodes a wealth of information about cosmology and the matter fluctuations. Its unbiased and optimal estimation is therefore of great importance. In this paper, we generalize the framework of Feldman et al. (1994) to take into account the fact that galaxies are not simply a Poisson sampling of the underlying dark matter distribution. Besides finite survey-volume effects and flux limits, our optimal estimation scheme incorporates several of the key tenets of galaxy formation: galaxies form and reside exclusively in dark matter haloes; a given dark matter halo may host several galaxies of various luminosities; galaxies inherit part of their large-scale bias from their host halo. Under these broad assumptions, we prove that the optimal weights do not explicitly depend on galaxy luminosity, other than through defining the maximum survey volume and effective galaxy density at a given position. Instead, they depend on the bias associated with the host halo; the first and second factorial moments of the halo occupation distribution; a selection function, which gives the fraction of galaxies that can be observed in a halo of mass M at position {r} in the survey; and an effective number density of galaxies. If one wishes to reconstruct the matter power spectrum, then, provided the model is correct, this scheme provides the only unbiased estimator. The practical challenges with implementing this approach are also discussed

Nurses Alumni Association Bulletin, Fall 1998

1998-1999 Meeting Date Calendar 1999 Annual Luncheon & Meeting Notice Fall Social Officers and Committee Chairs Bulletin Publication Committee The President\u27s Message Treasurer\u27s Report News About Our Graduates Highlight Of 1998 Operation Smile Scholarship Funds At Work Romania Trip Double Honors Doris Bowman Memorial Service For Janet Hindson A time for everything On the Lighter Side Twenty Ways to Kill an Organization Happy Birthday Fiftieth Anniversary Resume Alumni Association Meetings Alumni Office News Committee Reports Bulletin By-Laws Relief Fund Social Scholarship Development Nominating Luncheon Photos In Memoriam, Names of Deceased Graduates Class News Certification Reimbursement Application Relief Fund Application Scholarship Fund Application (new) Pins, Transcripts, Class Address List, Change of Address Forms Campus Ma

What do cluster counts really tell us about the Universe?

We study the covariance matrix of the cluster mass function in cosmology. We adopt a two-line attack: first, we employ the counts-in-cells framework to derive an analytic expression for the covariance of the mass function. Secondly, we use a large ensemble of N-body simulations in the Λ cold dark matter framework to test this. Our theoretical results show that the covariance can be written as the sum of two terms: a Poisson term, which dominates in the limit of rare clusters; and a sample variance term, which dominates for more abundant clusters. Our expressions are analogous to those of Hu & Kravtsov for multiple cells and a single mass tracer. Calculating the covariance depends on: the mass function and bias of clusters, and the variance of mass fluctuations within the survey volume. The predictions show that there is a strong bin-to-bin covariance between measurements. In terms of the cross-correlation coefficient, we find r≳ 0.5 for haloes with M≲ 3 × 1014 h−1 M⊙ at z= 0. Comparison of these predictions with estimates from simulations shows excellent agreement. We use the Fisher matrix formalism to explore the cosmological information content of the counts. We compare the Poisson likelihood model, with the more realistic likelihood model of Lima & Hu, and all terms entering the Fisher matrices are evaluated using the simulations. We find that the Poisson approximation should only be used for the rarest objects, M≳ 5 × 1014 h−1 M⊙, otherwise the information content of a survey of size V∼ 13.5 h−3 Gpc3 would be overestimated, resulting in errors that are nearly two times smaller. As an auxiliary result, we show that the bias of clusters, obtained from the cluster-mass cross-variance, is linear on scales >50 h−1 Mpc, whereas that obtained from the auto-variance is non-linea

Growth and Morphological Responses to Irradiance in Three Forest Understory Species of the C4 Grass Genus Muhlenbergia

This is the publisher's version, also available electronically from: http://www.jstor.org/stable/2995468.Three species of the C4 grass genus Muhlenbergia—M. frondosa, M. sobolifera, and M. schreberi— were collected from forest understory sites in northeastern Kansas and grown in a growth chamber at 1,500, 150, and 15-25 fjimol m~2 s - 1 photosynthetic photon flux density (PPFD). Leaf, stem, root, and total biomasses and several morphological and anatomical characteristics were measured after 35-38 days. Results were compared with similar measurements for M. cuspidata collected from exposed prairie sites. Although all species grew maximally at the highest PPFD, M. sobolifera grew equally well at medium PPFD. Few anatomical changes were correlated with changes in PPFD except leaf thickness, which increased with increasing PPFD. The results indicate that, while the understory species of Muhlenbergia can adjust morphologically to some extent to shaded environments, they produce more biomass at higher PPFD

Photosynthetic Responses to Irradiance in Three Forest Understory Species of the C4 Grass Genus Muhlenbergia

This is the publisher's official version, also available electronically from: http://www.jstor.org/stable/2995345Three species of the C4 grass genus Muhlenbergia—M.frondosa, M. sobolifera, and Af. schreberi—were collected from forest understory habitats in Kansas and grown in a growth chamber at 1,500, 150, and 15- 25 |xmol m"2 s"1 photosynthetic photon flux density (PPFD). Assimilation (A), conductance to C02 , intercellular C02 concentration, chlorophyll (chl) concentrations, and photosystem I electron-transport capacity were determined and compared with results for Af. cuspidata, which occurs only in open, prairie areas. All of the shade species exhibited more shade tolerance than the prairie species: they had lower maximum A, saturation of A, and photosystem I electron transport with respect to PPFD, higher quantum yields that increased with decreasing growth PPFD, and increasing chl concentrations with decreasing PPFD

Nurses Alumni Association Bulletin, Fall 1996

1996-1997 Meeting Dates Calendar 1997 Annual Luncheon-Meeting Notice Inside Officers and Committee Chairs Bulletin Publication Committee 1996-1997 Meeting Dates Calendar The President\u27s Message Treasurer\u27s Report News About Our Graduates Letter To Jefferson Nurses Fiftieth Anniversary Resume\u27 of Minutes of Alumni Association Meetings Alumni Office News Nursing Up-Date 1995-1996 Scholarship Funds At Work Diploma School of Nursing Alumni Association-Mabel C. Prevost Scholarship Report 1995 Women In Military Service For America Memorial Foundation Operation Support Freedom - Humanitarian Aid to Kiev The Best Mousetrap - Computers In Nursing Christmas, As A Prisoner Of War Restroom Policy Happy Birthday Committee Reports Bulletin Development Relief Fund Satellite Scholarship Social Luncheon Photos In Memoriam, Names of Deceased Graduates Class News Membership Application Relief Fund Application To Order: A Chronological History and Alumni Directory From TJU Bookstore Scholarship Fund Applicatio Pins, Transcripts, Class Address List, Change of Address Forms Campus Ma

The cosmology dependence of weak lensing cluster counts

We present the main results of a numerical study of weak lensing cluster counting. We examine the scaling with cosmology of the projected-density-peak mass function. Our main conclusion is that the projected-peak and the three-dimensional mass functions scale with cosmology in an astonishingly close way. This means that, despite being derived from a two-dimensional field, the weak lensing cluster abundance can be used to constrain cosmology in the same way as the three-dimensional mass function probed by other types of surveys.Comment: 4 pages, 2 figures. Accepted for publication in ApJL. Figure 1 modified, unchanged conclusion

Nurses Alumni Association Bulletin, Fall 1997

1997-1998 Meeting Dates Calendar 1998 Annual Luncheon-Meeting Notice Officers and Committee Chairs Bulletin Publication Committee 1997-1998 Meeting Dates Calendar The President\u27s Message Treasurer\u27s Report Trivia and News About Our Graduates Highlights of 1997 Keeping Kids Healthy After Hours Scholarship Funds At Work Tribute to Tanya Medical Mission Outreach 1996 History Of The Jefferson Pin Facts Not Fiction Rib Ticklers Mama Will Protect Me Happy Birthday Fiftieth Anniversary Resume of Minutes of Alumni Association Meetings Alumni Office News Committee Reports Bulletin By-Laws Development Diploma School of Nursing Alumni Association-Mabel C. Prevost Scholarship Fund Nominating Relief Fund Satellite Social Scholarship Luncheon Photos In Memoriam, Names of Deceased Graduates Class News Certification Reimbursement Application Relief Fund Application Scholarship Fund Application Pins, Transcripts, Class Address List, Change of Address Forms Campus Ma