1207.0002
The zCOSMOS 20k group catalog
Knobel et al
Optical group catalog between 0.1 < z < 1 based on 16500 high Q spec-z in zCOSMOS-bright (completed). 1498 groups (192 with >5 members). Purity of >3 member groups (based on mocks) is 83%; >75% should exhibit correspondence with "real" groups. At high z, more galaxies in groups in COSMOS field than expected from mock catalogs. Growth of cosmic structure : fraction of galaxies found in groups in volume-limited samples increases significantly with cosmic time. Then relate photo-z galaxies with spec-z id'ed groups; leads to improved definitions of group center, most massive galaxies in the groups, central and satellite galaxies (central = minimum of potential wells). Better purity (80%).
1207.0004
Cosmological constraints from a combination of galaxy clustering & lensing -- II. Fisher Matrix analysis
More, van den Bosch, Cacciato, More, Mo, Yang
Quantify accuracy of Omega_m, sigma_8, Omega_nu and w_0 constraints using large galaxy redshift surveys. Use galaxy clustering and gg WL to constrain HOD (galaxy bias) and cosmological parameters. Parameterize HOD with conditional luminosity function; use analytical framework of halo model to predict relevant observables. Joint analysis of observables can be used to obtain tight constraints on cosmo params, fully marginalized over uncertainties in galaxy bias. Demonstrate that the cosmo constraints from such an analysis are nearly uncorrelated with the HOD constraints.
1207.0005
A group-galaxy cross-correlation function analysis in zCOSMOS
Knobel et al
Present group-galaxy cross-correlation analysis. Consistency test in 0.2<z<0.8 between the clustering strength of groups and mass estimates that are based on the richness of the groups. Convert linear bias of groups (measured by group-gal Xcorr) and convert it into mass using bias-mass relation for a given cosmology. Measured bias increases with group richness, as expected (in comparison to 24 mocks), but the richest groups at high z (>1e13.5 Msun) has bias significantly larger than any of the 24 mocks (3 sigma effect), attributed to the extremely LSS that is present in the COSMO field at z~0.7.
1207.0007
Baryons matter: why luminous satellite galaxies have reduced central masses
Zolotov et al
High-res hydro-sims of MW-mass disk galaxies demonstrate that SNe feedback and tidal stripping lower the central masses of bright satellite galaxies. GMC resolved, H2 formation and destruction simulated. SNe feedback reduces DM densities and makes inner density profiles shallow in the massive satellite progenitors (Mdm>1eMsun, M*>1e7Msun) compared to DM-only sims. Progenitors of lower mass satellites unable to maintain bursty SFH, due to both heating at reionization and gas loss from initial SF events, preserving the inner density profile predicted by DM-only simulations. After infall, tidal stripping further reduce central densities of luminous satellites, particularly those that enter with cored DM haloes, increasing the discrepancy in the central masses predicted by baryon+DM and DM-only sims. DM-only sims produce denser satellites with larger central velocities.
1207.0015
Angular correlation of the CMB in the R_h=ct Universe
Melia
[What the *** is the R_h=ct universe?]
1207.0068
Evidence for spin alignment of spiral and elliptical galaxies in filaments
Tempel, Stoica, Saar
Using SDSS, study the connection between the spin axes of galaxies and the orientation of their host filaments. Find evidence that the spin axis of bright spiral galaxies have a weak tendency to be aligned parallel to filaments. For elliptical/S0 galaxies, a statistically significant result that the spin axis of ellipticals are aligned preferentially perpendicular to the host filaments; show that this signal does not depend on the accuracy of the estimated inclination angles for elliptical galaxies.
1207.0093
Esimating gas accretion in disc galaxies using the Kennicutt-Schmidt law
Fraternali, Tomassetti
* Matteo! Nice paper, Matteo.
K-S law (SFR and gas density relation) implies a continuous accretion of fresh gas from the environment into the disks of spiral galaxies. Derive a method that quantifies gas infall rate in a galaxy disc as a function of time and radius; apply to MW and 21 galaxies from THINGS. SFR higher in the past, but varies substantially with radius. Dependency with galaxy stellar mass and Hubble type (more constant SFH for small galaxies of later type). Gas accretion rate follows very closely the SFR for every galaxy and it dominates the evolution of these systems. The MW has formed 2/3 of its stars after z=1, while the mass of cold gas in the disc has remained fairly constant with time. In general, all discs have accreted a significant fraction of their gas after z=1. Accretion moves from the inner regions of ths disk to the outer parts, and as a consequence, SF moves inside-out as well. At z=0 the peak of gas accretion in the Galaxy is at about 6-7 kpc from the centre.
1207.0170
Single parameter galaxy classification: the principal curve through the multi-dimensional space of galaxy properties
Taghizadeh-Popp, Heinis, Szalay
"Principal Curve" passing through the spine of the data point cloud, used to classify galaxies by a single arc length value of the curve. P-curve allows dimensionality reduction, provides supporting evidence for relevant physical models and scenarios.
1207.0204
Discovering the missing bright quasars at intermediate redshifts based on the optical/near-IR color selections
Wu, Zuo, Yang, Yang, Wang
Optical colors of QSO similar to stars at 2.2<z<3.5. Use NIR K-band excess technique to overcome this. 35/43 were quasars, based on Y-K/g-z color, higher stellar contamination for 3<z<3.5 quasar candidates.
1207.0241
Ram pressure effects in the galactic plane and galactic dynamos in the no-z approximation
Moss, Sokoloff, Beck
Present a quantitative dynamo model which attempts to describe the B-field galaxies (produced by internal dynamo action) being affected by motion through IGM (ram pressure effects). Obtain displacements of the large-scale B field, as well as magnetic tails. The direction of B-field displacement is perpendicular to the wind direction. The tail is eventually directed downstream. Any determination of galactic motion through the cluster medium from observational data needs to take the effects of dynamo action into account.
1207.0264
Fully nonlinear and exact perturbations of the Friedmann world model
Hwang, Noh
Pragmatic formulation of cosmological perturbation theory which is powerful in practice to employ various fundamental gauge conditions easily spending o the character of the problem (Bardeen 1988). Except for the synchronous gauge condition, all other fundamental gauge conditions completely fix the gauge mode (each variable in such a gauge has a unique gauge invariant counterpart). Extend Bardeen's linear formulation to fully NL order in perturbations with the gauge advantage kept intact. Consider scalar- and vector-type perturbations of an ideal fluid in a flat background.
1207.0306
A 1-mm spectral line survey toward GLIMPSE Extended green objects (EGOs)
He, Takahashi, Chen
GLIMPSE EGOs (candidate massive young stellar objects) surveyed for molecular lines: 8 species detected (H13CO+, SiO, SO, CH3OH, CH3OCH3, CH3CH2CN, HCOOCH3, and HN13C). Universal similarity of density and thermal structures, and probably of shock properties, among all EGO clouds; shock should be produced within the natal clouds of the EGOs.
1206.0328
Importance of axion-like particles for very-high-energy astrophysics
Roncadelli, De Angelis, Galanti
Axion-like particles (ALPs): very light spin-zero bosons with a two-photon coupling, can give rise to observable effects in very-high-energy astrophysics. Above 100 GeV the horizon of the observable Universe progressively shrinks as the energy increases, due to scattering of beam photons off background photons in the optical and IR bands, which produces e+e- pairs. With large B-field, a blazar photon can oscillate into ALP and back into photon before reaching Earth, increasing effective mean free path of beam photons.
1207.0351
The two-phase formation history of spiral galaxies traced by the cosmic evolution of the bar fraction
Kraljic, Bournaud, Martig
Study evolution of galactic bars and the link with disk and spheroid formation in a sample of zoom-in cosmo sims (1e10-11 Msun). In models, bars are almost absent from the progenitors at z>1.5, remain rare down to z~1. Then bars are in 80% of spirals, easily observable in 2/3 at z<0.5. Quantitatively consistent with observed bar fraction. Predict: lower bar formation in lower-mass galaxies (also agrees with observation). Secular phase growth of disk galaxies corresponds to appearance of bars; presence of bars contributes to the growth of bulge. Late cosmo gas infall necessary to maintain some bars at z<1.
1207.0355
THe influence of cosmic rays in the circumnuclear molecular gas of NGC1068
Aladro et al
Column densities of most of the species better reproduce with the molecular gas is heavily pervaded by a high cosmic ray ionization rate of about 1000 teams that of MW.
[Tue **/50] Jul 3
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