Digital collections usage at the University of Illinois at Urbana-Champaign Library: 2015 report

This report analyzes administrative data (number of collections, total items) and web analytics usage data (sessions, users, page views) of the University of Illinois at Urbana-Champaign Library’s locally managed digital collections from July 30, 2014 to July 30, 2015.Ope

Personal digital archiving: An annotated bibliography for librarians and patrons

This project was in partial fulfillment of our LIS586: Digital Preservation class in the Fall semester of 2015. Our assignment was to create an annotated bibliography containing two reading lists for a public library that is trying to extend its service offerings to include advising patrons on how to preserve their personal digital materials. One list is for the librarian, the other for the patron. This is a legitimate resource for anyone wishing to find out more about or find a reliable reading list of sources about personal digital archiving.Ope

Legacy matters: How academic repositories can fulfill emotional requests

Am informal article about the intrinsically archival nature of these items and how they affected two patrons on a deeply emotional level

Special or sacred?: Tribal material stewardship in special collections

Written in partial fulfillment of LIS580 LEA, Rare Books and Special Collections Librarianship. An essay on issues of tribal material stewardship and curation in special collections.Ope

Buried treasure: How a deep data dive can uncover global language gems

This poster was presented at the annual Association of College and Research Libraries conference in 2017 in Baltimore, MD. Supplementary electronic handout was available for download from the conference website. Digitization projects are still a lively topic among academic libraries, although small in-house projects have become overshadowed by large scale partner projects like Google Books and the Internet Archive. By using the filtering power of Open Refine, leaders at the helm of their university libraries can put together collections of unique texts written in lesser used languages to bring to their digitization departments. By doing so, they can make scholars of less-studied languages more aware of the resources in their collections.Ope

Strategic digital collection development in academic libraries

This 2015 study uses web analytics, subject term analysis, and download statistics to gauge the presence, visibility, and popularity of University of Illinois digital collections on the web. With a grounding in current best practices, it provides a pragmatic methodology for the institutional analysis of digital collections with an eye to strategic digital collection development.Ope

X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The Fraction of Galaxies Hosting Active Nuclei

We present a measurement of the fraction of cluster galaxies hosting X-ray bright Active Galactic Nuclei (AGN) as a function of clustercentric distance scaled in units of $r_{500}$. Our analysis employs high quality Chandra X-ray and Subaru optical imaging for 42 massive X-ray selected galaxy cluster fields spanning the redshift range of $0.2 < z < 0.7$. In total, our study involves 176 AGN with bright ($R <23$) optical counterparts above a $0.5-8.0$ keV flux limit of $10^{-14} \rm{erg} \ \rm{cm}^{-2} \ \rm{s}^{-1}$. When excluding central dominant galaxies from the calculation, we measure a cluster-galaxy AGN fraction in the central regions of the clusters that is $\sim 3$ times lower that the field value. This fraction increases with clustercentric distance before becoming consistent with the field at $\sim 2.5 r_{500}$. Our data exhibit similar radial trends to those observed for star formation and optically selected AGN in cluster member galaxies, both of which are also suppressed near cluster centers to a comparable extent. These results strongly support the idea that X-ray AGN activity and strong star formation are linked through their common dependence on available reservoirs of cold gas.Comment: 9 Pages, 4 Figures, accepted for publication in MNRAS, please contact Steven Ehlert ([email protected]) with any querie

Cosmology and Astrophysics from Relaxed Galaxy Clusters II: Cosmological Constraints

We present cosmological constraints from measurements of the gas mass fraction, $f_{gas}$, for massive, dynamically relaxed galaxy clusters. Our data set consists of Chandra observations of 40 such clusters, identified in a comprehensive search of the Chandra archive, as well as high-quality weak gravitational lensing data for a subset of these clusters. Incorporating a robust gravitational lensing calibration of the X-ray mass estimates, and restricting our measurements to the most self-similar and accurately measured regions of clusters, significantly reduces systematic uncertainties compared to previous work. Our data for the first time constrain the intrinsic scatter in $f_{gas}$, $(7.4\pm2.3)$% in a spherical shell at radii 0.8-1.2 $r_{2500}$, consistent with the expected variation in gas depletion and non-thermal pressure for relaxed clusters. From the lowest-redshift data in our sample we obtain a constraint on a combination of the Hubble parameter and cosmic baryon fraction, $h^{3/2}\Omega_b/\Omega_m=0.089\pm0.012$, that is insensitive to the nature of dark energy. Combined with standard priors on $h$ and $\Omega_b h^2$, this provides a tight constraint on the cosmic matter density, $\Omega_m=0.27\pm0.04$, which is similarly insensitive to dark energy. Using the entire cluster sample, extending to $z>1$, we obtain consistent results for $\Omega_m$ and interesting constraints on dark energy: $\Omega_\Lambda=0.65^{+0.17}_{-0.22}$ for non-flat $\Lambda$CDM models, and $w=-0.98\pm0.26$ for flat constant-$w$ models. Our results are both competitive and consistent with those from recent CMB, SNIa and BAO data. We present constraints on models of evolving dark energy from the combination of $f_{gas}$ data with these external data sets, and comment on the possibilities for improved $f_{gas}$ constraints using current and next-generation X-ray observatories and lensing data. (Abridged)Comment: 25 pages, 14 figures, 8 tables. Accepted by MNRAS. Code and data can be downloaded from http://www.slac.stanford.edu/~amantz/work/fgas14/ . v2: minor fix to table 1, updated bibliograph