21 research outputs found

    Funding Climate Action: Pathways for Philanthropy

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    Increased greenhouse gas pollution is warming the planet quickly, threatening people, cultures, ecosystems, and global stability. We need a worldwide transition to clean, safe, accessible energy. This transition is complex and requires steady, staged progress. Too often, strategies for addressing the twin challenges of protecting the planet and promoting clean energy access have been slowed by divisions between and among nations, governments at all levels, the private sector, nonprofits, and advocates. At risk are the people and communities that need solutions.This report is a call to action. The solutions necessary to combat climate change are systemic and require collaboration across the public, private, nonprofit, and philanthropic sectors. Fortunately, there are also hopeful signs of progress, both globally and in the U.S. In the last few years, we have seen an acceleration of government funding, significant Net Zero commitments from corporations, and an important increase in philanthropy focused on climate adaptation and mitigation.

    The Bottom Line: Investing for Impact on Economic Mobility in the U.S.

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    There is no greater challenge in the United States today than income inequality. It has been 50 years since the War on Poverty began. We have made progress but not enough. More than 32 million children live in low-income families, and racial and gender gaps persist. For the first time, Americans do not believe life will be better for the next generation. We have both a moral and an economic imperative to fuel social and economic mobility in this country.The Aspen Institute was founded in 1950 as a place to address the critical issues of our time. Today, ensuring that the American dream can be a possibility for all and be passed from one generation to the next is that issue. This commitment is at the heart of the work of many policy programs at the Aspen Institute. Ending the cycle of poverty requires leadership and hard work across all sectors, from nonprofit organizations, philanthropies, and academia to the government and private sector. This report recognizes the importance of learning from all sectors in tackling any challenge. Specifically, it builds on opportunities in the growing impact investment field. The report draws on the lessons from market-based approaches to identify tools and strategies that can help move the needle on family economic security. In this report, you will find the following: Case studies -- An opportunity to go under the hood on deals with the Bank of America, W.K. Kellogg Foundation, Acelero Learning, and others; Point of view essays -- Insights and lessons from leaders in the field; Deals at a glance -- Snapshots of impact investors and what they have learned, including the Kresge Foundation, Living Cities, and the MacArthur Foundation; and Survey results and lessons learned -- Trends among active and emerging players in the U.S. impact investment field and the lessons that can be applied to economic mobility in the U.S. We are pleased to offer this expanded perspective on impact investing in the U.S. and the lessons for investors, philanthropists, and non-profits working to build strong and prosperous families and communities

    The three-dimensional geometry and merger history of the massive galaxy cluster MACS J0358.8-2955

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    We present results of a combined X-ray/optical analysis of the dynamics of the massive cluster MACS J0358.8-2955 (z=0.428) based on observations with the Chandra X-ray Observatory, the Hubble Space Telescope, and the Keck-I telescope on Mauna Kea. MACS J0358.8-2955 is found to be one of the most X-ray luminous clusters known at z>0.3, featuring L_X(<r_500) = 4.24*10^45 erg/s, kT = (9.55 +0.58/-0.37) keV, M^{3D}_{gas}(<r_500) = (9.18+/-1.45)*10^13 M_sun, and M^{3D}_{tot}(<r_500) = (1.12+/-0.18)*10^15 M_sun. The system's high velocity dispersion of (1440 +130/-110) km/s (890 km/s when the correct relativistic equation is used), however, is inflated by infall along the line of sight, as the result of a complex merger of at least three sub-clusters. One collision proceeds close to head-on, while the second features a significant impact parameter. The temperature variations in the intra-cluster gas, two tentative cold fronts, the radial velocities measured for cluster galaxies, and the small offsets between collisional and non-collisional cluster components all suggest that both merger events are observed close to core passage and along axes that are greatly inclined with respect to the plane of the sky. A strong-lensing analysis of the system anchored upon three triple-image systems (two of which have spectroscopic redshifts) yields independent constraints on the mass distribution. For a gas fraction of 8.2%, the resulting strong-lensing mass profile is in good agreement with our X-ray estimates, and the details of the mass distribution are fully consistent with our interpretation of the three-dimensional merger history of this complex system.Comment: 17 pages, 17 figures, and 4 tables. Accepted for publication in MNRA

    Spiral-like structure in nearby clusters of galaxies

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    X-ray data analysis have found that fairly complex structures at cluster centres are more common than expected. Many of these structures have similar morphologies, which exhibit spiral-like substructure. It is not yet well known how these structures formed or are maintained. Understanding the origin of these spiral-like features at the centre of some clusters is the major motivation behind this work. We analyse deep \textit{Chandra} observations of 15 nearby galaxy clusters (0.01 <z< < z < 0.06), and use X-ray temperature and substructure maps to detect small features at the cores of the clusters. We detect spiral-like features at the centre of 7 clusters: A85, A426, A496, Hydra A cluster, Centaurus, Ophiuchus, and A4059. These patterns are similar to those found in numerical hydrodynamic simulations of cluster mergers with non-zero impact parameter. In some clusters of our sample, a strong radio source also occupies the inner region of the cluster, which indicates a possible connection between the two. Our investigation implies that these spiral-like structures may be caused by off-axis minor mergers. Since these features occur in regions of high density, they may confine radio emission from the central galaxy producing, in some cases, unusual radio morphology.Comment: 14 pages, 3 figures, accepted for publication in A&A (Nov 17, 2009

    The Atacama Cosmology Telescope: ACT-CL J0102-4915 "El Gordo," a Massive Merging Cluster at Redshift 0.87

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    We present a detailed analysis from new multi-wavelength observations of the exceptional galaxy cluster ACT-CL J0102-4915 "El Gordo," likely the most massive, hottest, most X-ray luminous and brightest Sunyaev-Zeldovich (SZ) effect cluster known at z>0.6. The Atacama Cosmology Telescope collaboration discovered El Gordo as the most significant SZ decrement in a sky survey area of 755 deg^2. Our VLT/FORS2 spectra of 89 member galaxies yield a cluster redshift, z=0.870, and velocity dispersion, s=1321+/-106 km/s. Our Chandra observations reveal a hot and X-ray luminous system with an integrated temperature of Tx=14.5+/-1.0 keV and 0.5-2.0 keV band luminosity of Lx=(2.19+/-0.11)x10^45 h70^-2 erg/s. We obtain several statistically consistent cluster mass estimates; using mass scaling relations with velocity dispersion, X-ray Yx, and integrated SZ, we estimate a cluster mass of M200a=(2.16+/-0.32)x10^15 M_sun/h70. The Chandra and VLT/FORS2 optical data also reveal that El Gordo is undergoing a major merger between components with a mass ratio of approximately 2 to 1. The X-ray data show significant temperature variations from a low of 6.6+/-0.7 keV at the merging low-entropy, high-metallicity, cool core to a high of 22+/-6 keV. We also see a wake in the X-ray surface brightness caused by the passage of one cluster through the other. Archival radio data at 843 MHz reveal diffuse radio emission that, if associated with the cluster, indicates the presence of an intense double radio relic, hosted by the highest redshift cluster yet. El Gordo is possibly a high-redshift analog of the famous Bullet Cluster. Such a massive cluster at this redshift is rare, although consistent with the standard L-CDM cosmology in the lower part of its allowed mass range. Massive, high-redshift mergers like El Gordo are unlikely to be reproduced in the current generation of numerical N-body cosmological simulations.Comment: Typo on metadata fixed on version 3. Accepted for publication in The Astrophysical Journal; 17 pages, 15 figures. New section 4.4 includes radio relic scienc

    Clusters of galaxies : observational properties of the diffuse radio emission

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    Clusters of galaxies, as the largest virialized systems in the Universe, are ideal laboratories to study the formation and evolution of cosmic structures...(abridged)... Most of the detailed knowledge of galaxy clusters has been obtained in recent years from the study of ICM through X-ray Astronomy. At the same time, radio observations have proved that the ICM is mixed with non-thermal components, i.e. highly relativistic particles and large-scale magnetic fields, detected through their synchrotron emission. The knowledge of the properties of these non-thermal ICM components has increased significantly, owing to sensitive radio images and to the development of theoretical models. Diffuse synchrotron radio emission in the central and peripheral cluster regions has been found in many clusters. Moreover large-scale magnetic fields appear to be present in all galaxy clusters, as derived from Rotation Measure (RM) studies. Non-thermal components are linked to the cluster X-ray properties, and to the cluster evolutionary stage, and are crucial for a comprehensive physical description of the intracluster medium. They play an important role in the cluster formation and evolution. We review here the observational properties of diffuse non-thermal sources detected in galaxy clusters: halos, relics and mini-halos. We discuss their classification and properties. We report published results up to date and obtain and discuss statistical properties. We present the properties of large-scale magnetic fields in clusters and in even larger structures: filaments connecting galaxy clusters. We summarize the current models of the origin of these cluster components, and outline the improvements that are expected in this area from future developments thanks to the new generation of radio telescopes.Comment: Accepted for the publication in The Astronomy and Astrophysics Review. 58 pages, 26 figure
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