Day 893

Tuesday.


1505.06199
The SDSS-IV in 2014: A demographic snapshot
Lundgren, et al

CPWS (Committee on the Participation of Women in SDSS) administered a demographic survey in SDSS-IV.  From 250 participants, or 46% of active membership, responses show: 50% in US or Canada, 30% based in Europe; 11% considered themselves ethnic minority at their current institution.  25% members are women, consistent with US astro community, and substantially higher than fraction of women in IAU (16%).  Approximately equal fraction of men and women report holding positions of leadership.  When binned by academic age and career level, men and women also assume leadership roles at approximately equal rates, in a way that increases steadily for both genders with increasing seniority.  SDSS-IV has been successful in recruiting leaders that are representative of the collaboration, yet more progress needs to be made towards achieving gender imbalance and increasing diversity in the field of astronomy.  For example, at the highest level of SDSS-IV leadership, women disproportionately assume roles related to education and public outreach.  CPWS plans to use these initial data to establish a baseline for tracking demographics over time.


1505.06501
Direct shear mapping - a new weak lensing tool
de Burgh-Day et al

DSM (Direct Shear Mapping) developed to measure GL shear directly from observations of a single background source.  The technique assumes the velocity map of an un-lensed, stably-rotating galaxy will be rotationally symmetric.  Lensing distorts the velocity map making it asymmetric.  The degree of lensing can be inferred by determining the transformation required to restore axisymmetry.  This technique is in contrast to traditional weak lensing methods, which require averaging an ensemble of background galaxy ellipticity measurements, to obtain a single shear measurement.  Test the efficacy of the fitting algorithm with a suite of systematic tests on simulated data.  Demonstrate that in principle able to measure shears as small as 0.01. In practice, fitted for the shear in a avery low z ( and hence unlicensed)velocity maps, and have obtained null results with an error of ±0.01.  This high sensitivity results from analyzing spatially resolved spectroscopic images (i.e., 3D data cubes), including not just shape information (as in traditional WL measurements) but velocity information as well.  Spirals and rotating ellipticals are ideal targets for this new technique.  Data from any large IFU or radio telescope is suitable, or indeed any instrument with spatially resolved spectroscopy such as SAMI, ALMA, HETDEX and SKA.