Day 800

Friday.

1412.1472
New redshift z~9 galaxies in the Hubble Frontier Fields: Implications for early evolution of the UV luminosity density
McLeod et al

Survey covering an effective area of 10.9 sq arcmin (after accounting for magnification) which yields 12 galaxies at 8.4<z<9.5 (based on photo-z).  Also uncover 4 z~9 galaxies.  Based on published magnification maps, find that only on of the 12 is likely boosted by more than a factor of 2 by gravitational lensing.  Consequently, perform a fairly straightforward reanalysis of the normalization of the z~9 UV galaxy LF as expired previously in the HUDF12 program.  Conclude that the new data strengthen the evidence for a continued smooth decline in UV luminosity density (and hence SFR density) from z~8 to 9, contrary to recent reports of a marked drop-off at these redshifts.  This provide further support for the scenario in which early galaxy evolution is sufficiently extended to explain cosmic reionization.  

1412.1482
Overview of the SDSS-IV MaNGA survey: mapping nearby galaxies at Apache Point Observatory
Bundy, et al

Overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of 3 core programs in SDSS-IV that began 2014 July 1.  MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10k nearby galaxies.  Summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential.  MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12" (19 fibers) to 32" (127 fibers).  Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300A at R~2000.  With a typical integration time of 3 hr, MaNGA reaches a target r-band S/N of 4-8 (per A, per 2" fiber) at 23 AB mag per sq arcsec, which is typical for the outskirts of MaNGA galaxies.  Targets are selected with stellar mass greater than 1e9 Msun using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments.  Analysis of prototype observations demonstrate MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constitution components, and map the composition of stellar populations.  MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 years.

1412.1507
Protocluster discovery in tomographic Ly$\alpha$ forest flux maps
Stark, White, Lee, Hennawi

Present a new method of finding protoclusters using tomographic maps of Lya Forest flux.  Review method of creating tomographic flux maps and discuss new high performance implementation, which makes large reconstructions computationally feasible.  Using a large N-body simulation, illustrate how protoclusters create large-scale flux decrements, roughly 10 Mpc/h across, and how we can use this signal to find them in flux maps.  Test the performance of protocluster finding method by running it on the ideal, noiseless map and tomographic reconstructions from mock surveys, and comparing to the halo catalog.  Using the noiseless map, find protocluster candidates with about 90% purity, and recover about 75% of the protoclusters that form massive clusters (>3e14 Msun/h).  Construct mock surveys similar to the ongoing COSMOS Ly-A mapping And Tomography Observations (CLAMATO) survey  While the existing data has an average sightling separation of 2.3 Mpc/h, test separations of 2-6 Mpc/h to see what can be tolerated for the application.  Using reconstructed maps from small separation mock surveys, the protocluster candidate purity and completeness are very close to what was found in the noiseless case,  As the sightline separation increases, the purity and completeness decrease, although they remain much higher than initially expected.  Extend test cases to mock surveys with an average separation of 15 Mpc/h, meant to reproduce high source density areas of the BOSS survey.  Find that even with such a large sightline separation, the method can still be used to find some f the largest protoclusters.