Day 112

Friday (already?).  Aaron left yesterday.  Today I sign my rent contract.  Thanks to Philippe for all his help.


1110.4370
Gravitationally consistent halo catalogs and merger trees for precision cosmology
Behroozi, Wechsler, Wu, Busha, Klypin, Primack


New algorithm for generating merger trees and halo catalogs which explicitly ensures consistency of halo properties (mass, position, velocity, radius) across timesteps.  Demonstrated ability to improve both the completeness (through detecting and inserting otherwise missing halos) and purity (through detecting and removing spurious objects) of both merger trees and halo catalogs.  Able to robustly measure self-consistency of halo finders; first to directly measure uncertainties in halo positions, velocities, and halo mass function for a given halo finder, based on consistence between snapshots in cosmo simulations.  Evaluate ROCKSTAR and BDM halo finders; both track haloes very well, bsed on the number of haloes which do not have consistent progenitors (1-2 % level across all halo masses).  Code available.


1110.4371
AGES: The AGN and Galaxy Evolution Survey
Kochaneck, Eisenstein, Cool, Caldwell, Assef, Jannuzi, Jones, Murray, Forman, Dey, Brown, Eisenhardt, Gonzalez, Green, Stern


AGES is a redshift survey covering 7.7 square degrees of the Bootes field of NOAO Deep Wide-Field Survey (NDWFS).  Final sample has 23745 redshifts.  Well defined galaxy samples in ten bands (Bw, R, I, J, K, IRAC 3.6, 4.5, 5.8 and 8.0 micron and MIPS 24 micron bands) to a limiting magnitude of I<20 mag for spectroscopy.  For these galaxies, obtained 18163 redshifts from a sample of 35200 galaxies, where random sparse sampling was used to define statistically complete sub-samples in all ten photometric bands.  Median galaxy redshift is 0.31, and 90% of redshifts are in the range 0.085<z<0.66.  AGN were selected as radio, X-ray, IRAC and mid-IR and MIPS 24 micron sources to fainter limiting magnitudes (I<22.5 mag for point sources).  Redshifts were obtained for 4764 quasars and galaxies with AGN signatures, with 2926, 1718, 605, 119 and 13 above z of 0.5, 1, 2, 3, and 4, respectively.  Selection procedures and spectroscopic redshift catalogs, spectra, and spectral energy distribution presented.  Photometric redshift estimates are for all sources in the AGES samples.


1110.4372
The ROCKSTAR Phase-space temporal halo finder and the velocity offsets of cluster cores
Behroozi, Wechsler, Wu


A new algorithm for identifying DM halos, substructure, and tidal features, based on adaptive hierarchical refinement of FoF groups in six phase-space dimensions and one time dimension.  Allows for robust (grid-independent, shape-independent, noise-resilient) tracking of substructure.  Massively parallel, 1e10 particles with high efficiency (10 CPU hours and 60 GB of memory required per billion particles analyzed).  Significant improvement in substructure recovery as compared to several other halo finders and discuss the theoretical and practical limits of simulations with regard to substructures.  Present results which demonstrate conclusively that DM halo cores are not at rest relative to the halo bulk or satellite average velocities, and have coherent velocity offsets across a wide range of halo masses and redshifts.  For massive clusters, these offsets can be up to 400 km/s at z=0 and even higher at high redshifts.  


MPIfR Bonn Lunch Colloquium
A new type of compact stellar population: dark star clusters
Sambaran Banerjee


* same topic as the recently submitted paper


Retention of SNe remnants in star clusters.  




MPIfR Bonn Master Colloquium (Oct 25)
Relativistic propagation effects in binary pulsars and the next generation of radio telescopes
Masooma Ali


Testing GR with binary pulsars possible with accurate measurement and analysis of time-of-arrivals (TOAs) of the pulses.  Timing models are based on post-Newtonian approximation for the Shapiro propagation delay; its limitations need to be understood.  Use models with analytic calculations and detailed fake data simulations.  Results, mandatory timing precision for higher order corrections discussed. Conclusions for the most relativistic systems known at present and for different configurations of pulsar binaries that may be discovered in the future.


MPIfR Bonn Special Colloquium (Oct 25, 14:00, 0.02)
Mopra and the central molecular zone / Astronomy in Antarctica
Michael Burton


- Central molecular zone (CMZ) holds the greatest collection of molecular gas in our Galaxy, and environment which is denser, warmer and more turbulent than the molecular medium found in the spiral arms.  Provides a panoramic view of what a galactic nucleus may look like.  The Mopra telescope has been used to undertake a multiple molecular line mapping survey of the CMZ, mapping the distribution of 18 molecular lines across it.  Overview of data set; some interesting avenues of investigation.


- Astrophysical endeavors in Antarctica (neutrino telescope, CMB, optical/IR/mm astronomy).  Astronomy underway at 4 Antarctic plateau stations, as well as long-range ballooning around the coast.  Overview activities; opportunities from the clear, cold, dry and stable conditions of the high plateau present for future study of the cosmos.