Dry Mergers in GEMS: The Dynamical Evolution of Massive Early-Type Galaxies

We have used the 28'x 28' HST image mosaic from the GEMS (Galaxy Evolution from Morphology and SEDs) survey in conjunction with the COMBO-17 photometric redshift survey to constrain the incidence of major mergers between spheroid-dominated galaxies with little cold gas (dry mergers) since z = 0.7. A set of N-body merger simulations was used to explore the morphological signatures of such interactions: they are recognizable either as < 5kpc separation close pairs or because of broad, low surface brightness tidal features and asymmetries. Data with the depth and resolution of GEMS are sensitive to dry mergers between galaxies with M_V < -20.5 for z < 0.7; dry mergers at higher redshifts are not easily recovered in single-orbit HST imaging. Six dry mergers (12 galaxies) with luminosity ratios between 1:1 and 4:1 were found from a sample of 379 red early-type galaxies with M_V < -20.5 and 0.1 < z < 0.7. The simulations suggest that the morphological signatures of dry merging are visible for ~250Myr and we use this timescale to convert the observed merger incidence into a rate. On this basis we find that present day spheroidal galaxies with M_V < -20.5 on average have undergone between 0.5 and 2 major dry mergers since z ~ 0.7. We have compared this result with the predictions of a Cold Dark Matter based semi-analytic galaxy formation model. The model reproduces the observed declining major merger fraction of bright galaxies and the space density of luminous early-type galaxies reasonably well. The predicted dry merger fraction is consistent with our observational result. Hence, hierarchical models predict and observations now show that major dry mergers are an important driver of the evolution of massive early-type galaxies in recent epochs.Comment: ApJ, in press. The paper has been extensively modified, detailing the automated+visual selection and dry merger classification. 11 pages emulateapj with 9 reduced-quality figures. A high quality copy is available at http://www.mpia-hd.mpg.de/homes/bell/papers/dry.ps.g

The arts of action

The theory and culture of the arts has largely focused on the arts of objects, and neglected the arts of action – the “process arts”. In the process arts, artists create artifacts to engender activity in their audience, for the sake of the audience’s aesthetic appreciation of their own activity. This includes appreciating their own deliberations, choices, reactions, and movements. The process arts include games, urban planning, improvised social dance, cooking, and social food rituals. In the traditional object arts, the central aesthetic properties occur in the artistic artifact itself. It is the painting that is beautiful; the novel that is dramatic. In the process arts, the aesthetic properties occur in the activity of the appreciator. It is the game player’s own decisions that are elegant, the rock climber’s own movement that is graceful, and the tango dancers’ rapport that is beautiful. The artifact’s role is to call forth and shape that activity, guiding it along aesthetic lines. I offer a theory of the process arts. Crucially, we must distinguish between the designed artifact and the prescribed focus of aesthetic appreciation. In the object arts, these are one and the same. The designed artifact is the painting, which is also the prescribed focus of appreciation. In the process arts, they are different. The designed artifact is the game, but the appreciator is prescribed to appreciate their own activity in playing the game. Next, I address the complex question of who the artist really is in a piece of process art — the designer or the active appreciator? Finally, I diagnose the lowly status of the process arts

Spartan Daily, October 5, 1982

Volume 79, Issue 26https://scholarworks.sjsu.edu/spartandaily/6938/thumbnail.jp

Inside magazine, December 2013-January 2014

Iowa Department of Transportation Newsletter. INSIDE Magazine is developed to help keep all Iowa DOT employees informed about critical issues affecting them, recognize DOT employees for their excellent service and share interesting aspects in the lives of our co-workers

Unsafe and Harassed in Public Spaces: A National Street Harassment Report

From "hey baby" to "stupid fag," from flashing to groping, sexual harassment in public spaces, or "street harassment," is a problem many people experience, some with profound consequences. Since 2008, Stop Street Harassment (SSH) has collected thousands of street harassment stories. This groundbreaking study confirms what the stories suggest: Across all age, races, income levels, sexual orientations, and geographic locations, most women in the United States experience street harassment. Some men, especially men who identify as gay, bisexual, queer, or transgender, do as well.This report presents the findings of a 2,000-person, nationally representative survey (approximately 1,000 women and 1,000 men, ages 18 and up). GfK, a top surveying firm, conducted the Internet-based survey in February and March 2014. Additionally, SSH conducted 10 focus groups across the nation from August 2012 to March 2014.Street harassment is a human rights violation and a form of gender violence. It causes many harassed persons, especially women, to feel less safe in public places and limit their time there. It can also cause people emotional and psychological harm. Everyone deserves to be safe and free from harassment as they go about their day