1112.0001
Comparison of synthetic maps from truncated jet--formation models with YSO jet observations. II. The effect of varying inclinations
Stute, Gracia
Compare observed jet widths with models: models of jets from truncated disks (evolved in time numerical simulations based on a radially self-similar MHD solution, but including the effects of a finite radius of the jet-emitting disk and thus the outflow).
1112.0005
COSMOGRAIL: the cosmological monitoring of gravitational lenses X. Modeling based on high-precision astrometry of a sample of 25 lensed quasars: consequences for ellipticity, shear, and astrometric anomalies
Sluse, Chantry, Magin, Courbin, Meylan
Gravitational lens: (i) infer the Hubble constant from time-delays, (ii) unveil substructures along the LoS toward distant galaxies, (iii) compare the shape and slope of baryons and DM distributions in galaxies. These require high-accuracy astrometry and morphology measurements of the lens. Better astrometry (1-2.5 mas) and shape measurement for 11 lenses with time delays, combine with 14 other and get new mass models of these lenses. (1) in 4 double-image quasars, the influence of the lens environment on the time delay can easily be quantified and modeled. (2) For quadruple-image quasars, the difficulty in reproducing the image positions to milli-arcsec accuracy (astrometry anomaly) is overcome by including the nearest visible galaxy in the model (although one of them do not show any luminous perturber in the vicinity, while 3 other have problematic modeling--perturbation by DM structures possible. (3) Significant correlation between the PA of the light and the mass distributions in lensing galaxies. Ellipticity of the light and mass also correlate well, suggesting overall spatial distribution of matter is not very different from the baryon distribution in the inner ~5 kpc of lensing galaxies. [why do the other studies disagree with the PA alignment? why do you trust yours more?]
1112.0006
The evolution of the rest-frame J- and H-band luminosity function of galaxies to z=3.5
Stefanon, Marchesini
IR LF of field galaxies from data over 450 arcmin^2, from Spitzer IRAC 3.6, 4.5, 5.8 and 8 um channels in MUSYC, FIRES and FIREWORKS survey. From 4 redshift bins, 1.5<z1<2.0< z2 < 2.5 < z3 < 3.0 < z4 < 3.5. Find (1) faint-end slope consistent with being constant up to z=2.5, (2) the normalization phi* decreases by a factor of 6 between z=0 and z~1.75, and by a factor of 3 between z~1.75 and z=3.25; (3) the characteristic magnitude M* shows a brightening from z=0 to z~2 followed by a slow dimming to z=3.25. Compute the luminosity density in both rest-frame J and H bands. The analysis of our results together with those available in the literature show that the luminosity density is approximately constant up to z~1, and then decreases by a factor of 6 up to z=3.5.
1112.0008
The power spectrum from the angular distribution of galaxies in the CFHTLS-Wide fields at z~0.7
Granett, .. Coupon, Arnouts, .. Ilbert, McCracken, Mellier, et al
Galaxy power spectrum on large scales at z~0.5 to 1.2 using optical colour-selected samples from the CFHT legacy survey, with VIPERS ~14000 spectro sample, deproject angular distribution and directly estimate the 3d power spectrum. Use maximum likelihood estimator optimal for gaussian random field, giving welldefined window functions and error estimates. Meausrement presents an initial look at the LSS probed by VIPERS survey. Measure galaxy bias of VIPERS-like sample to be b_g=1.38 (sigma_8=0.8) on scales k<0.2h/Mpc averaged over 0.5<z<1.2. Investigate 3 redshift slices, marginalize over bias factors while keeping other LCDM parameters fixed. Find matter density Omega_m=0.30 pm 0.06.
1112.0009
Adaptive mesh refinement simulations of galaxy formation: exploring numerical and physical parameters
Hummels, Bryan
AMR cosmo sims of MW mass haloes to investigate disk-like galaxies in LCDM model, evolved to z=0 and find gaseous disk in all, but the rotation curves of all haloes are centrally peaked due to massive spheroidal component. Investigate angular momentum problem by systematically modifying various simulation parameters including (i) spatial resolution (ii) additional pressure component to ensure that the Jeans length is always resolved, (iii) low star formation efficiency, going down to 0.1%, (iv) fixed physical resolution as opposed to comoving resolution, (v) a SNe feedback model which injects thermal energy to the local cell, and (vi) a subgrid feedback model which suppresses cooling in the immediate vicinity of SF event. Only the last (cooling suppression) has any impact on the massive shperoidal component, the peak considerably reduced.
1112.0010
Halo pairs in the millennium simulation: love & deception
Moreno
Huge catalog of closely interacting pairs of DM haloes from Millennium. Only haloes that reach a minimum mass greater than 8.6e10 Msun/h (100 particles) are considered. Close pairs are selected if they come within a critical distance d_crit. Explore effects of replacing d_crit=1Mpc/h with 200 kpc/h on the evolution of separations, lifetimes, total masses and mass ratios of these pairs.
1112.0016
The very massive and hot LMC star VFTS 682: Progenitor of a future dark gamma-ray burst?
Zhang, Stanek
VFTS 682, a very massive and hot WR star in LMC--likely its properties result from chemically homogeneous evolution (CHE), believed to be a key process for a massive star to become a GRB. Also heavily obscured by dust extinction, which could make it a dark GRB upon explosion. Use Spitzer to investigate the properties of interstellar dust in the vicinity, and argue that its high obscuration is not unusual for its environment and that it could be a slow runaway from the nearby cluster R136. Due to its current mass loss rate, it is unlikely to become a GRB, because it will lose too much angular momentum at its death. One of the only 3 presently identified WR stars (two others in SMC) that seems to be undergoing CHE.
* what is chemically homogeneous evolution in a star?
1112.0019
The dynamics of stars around spiral arms
Grand, Kawata, Cropper
N-body sims of giant disc galaxy consisting of a pure stellar disc and a static DM halo. Find spiral amrs are transient features whose patter speeds decrease with radius, in such a way that the pattern speed is almost equal to the rotation curve of the galaxy. Trace particle motion around spiral arms, they are drawn towards, and join, the arm. Particles move along the arm in the radial direction; find that they migrate towrad the outer radii in the trailing side of the arm, and vice versa. Particles continue to be accelerated by the spiral arm for long periods, leading to strong and efficient migration, at all radii in the disc.
1112.0022
Relation of astrophysical turbulence and magnetic reconnection
Lazarian, Eyink, Vishniac
Astrophysical fluids are generically turbulent, important for transport processes. Preexisting turbulence modifies magnetic reconnection, magnetic reconnection affects the MHD turbulent cascade. Strong magnetic turbulence in 3d requires reconnection, and 3d magnetic turbulence entails fast reconnection. ...
1112.0025
BL Lacertae objects beyond redshift 1.3 - UV-to-NIR photometry and photometric redshift for Fermi/LAT blazars
Rau et al
BL Lac objects (blazars) are hard to get spectroscopic redshifts due to the quasi-featureless optical spectra. For 103 Fermi/LAT blazars, photometric redshifts using SED fitting obtained, with 13 broad-band filters from FUV to NIR with Swift/UVOT and MPG/ESO 2.2m telescope. Data taken quasi-simultaneously, and remaining source-intrinsic variability taken into account. Eight have reliable photo-z out to z>1.3; for other 67 there are upper limits.
1112.0026
The influence of gas dynamics on measuring the properties of BH in the center of MW with stellar orbits and pulsars
Psaltis
Hydrodynamic drag does not preclude measurements of the BH spin and quadrupole moment using high-res observations of stars and pulsars that orbit within a few k gravitational radii from its horizon.
1112.0029
On the evolution of the SF rate function of massive galaxies. COnstraints at 0.4<z<1.8 from the GOODS-MUSIC catalog
Fontanot, Cristiani, et al
Show theoretical SFRF (star formation rate function) well described by a double power law functional form and its redshift evolution is approximated with high accuracy by a pure evolution of the typical SFR. Good agreement between model predictions and the high-SFR end of the SFRF when observational errors are taken into account. Observational SFRF characterised by a double peaked structure, which is absent in the theoretical counterparts, overpredits the space density of SFR~1 Msun/yr.
Observe 9 clusters with 3 different x-ray satellite telescopes to study galaxy clusters at z~0.1 to 0.2, near their virial radius. Analysis indicates that the ICM is not in hydrostatic equilibrium in the cluster outskirts, clear azimuthal variations in temperature and surface brightness. One cluster show diffuse X-ray emission well beyond r_200; find entropy profile and gas fraction are consistent with expectations from theory and numerical simulations. Results stand in contrast to recent studies which point to gas clumping in the outskirts; extent of differences of cluster environment or instrumental effects that factor into this difference is unclear.
1112.0035
Constraining the physical properties of Type II-P SNe using nebular phase spectra
Maguire et al
SNe IIP have small diversity within the dataset, explained by strong mixing occurring during the explosion, and recognising that most lines have significant contributions from primordial metals in the H envelope, which dominate the ejecta mass. Correlation between Halpha and 56 Ni presented, suggesting higher energy explosion associated with higher 56 Ni production.
1112.0036
Probing relativistic astrophysics around SMBHs: the Suzaku AGN spin survey
Reynolds et al
Spin of SMBH observed from X-ray spectral features from the inner regions of BH accretion disks--probing the location of the innermost stable circular orbit, and hence the spin.
1112.0063
Dust reddening in star-forming galaxies
Xiao et al
Dust reddening modeling based on ~22000 SDSS star forming galaxies; reddening correlated with galaxy inclination, Halpha luminosity/surface brightness and gas phase metallicity. Empirical relation reproduced if most dust attenuation to the HII region is due to diffuse background dust distributing in a disc thicker than that of HII region. The empirical formulae can be incorporated into semi-analytical models of galaxy formation and evolution to estimate the dust reddening.
1112.0176
A new super-soft X-ray source in the SMC: discovery of the first Be/WD system in the SMC?
Sturm et al
Large number of Be/X-ray binaries found, but Be/WD system is rare.
1112.0274
Understanding how planets become massive. I. Description and validation of a new toy model
Ormel, Kobayashi
Formation of planets requires accumulation of up to ~10 M_earth in solids. Toy model with fragments, planetesimals, embryos; planetesimal collisions results in fragmentation, the mall particles interact with gas. The efficiency of accretion becomes sensitive to gas properties, such as turbulent state and magnitude of the disk headwind, as well as the fragment size.
1112.0285
The evolution of galaxy formation
Scott
A cynic's review of the evolution of ideas in galaxy formation.
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