Saturday. Lost most of today because of the late night/early morning drinking (5am). I was supposed to work on Capak scripts and ...
Now it's Sunday. I totally blew off yesterday by sleeping.
1107.0963
The effect of the environment on the gas kinematics and the structure of distant galaxies
Jaffe et al.
In clusters, the galaxies are not visibly disturbed (i.e., the stellar structure), but the gas structure is (via emission lines), and that's due to the gas in the cluster.
1107.1049
GOODS-HERSCHEL: evidence for a UV extinction bump in galaxies at z > 1
Buat et al.
* what about dust attenuation curves?
The presence or absence of a UV bump at 2175A has consequences on the interpretation of broad band colors of distant galaxies, but this remains an open issue. Derivation of the slopes of the UV continuum from broad-band colors is slightly steeper than before. Uncertainties on the determination of the UV slope leads to an extra systematic error of 0.3 to 0.7 mag on dust attenuation when a filter overlaps the UV bump.
* I don't really get it.
1107.0972
Redshift evolution of the galaxy velocity dispersion function
Bezanson et al
Previous study demonstrated that dynamical and stellar mass are linearly related when the structure of the galaxy is accounted for (Taylor+2010); show the stellar mass, size and Sersic index can reliably predict the velocity dispersions of SDSS galaxies. Apply this relation at high redshift; determine the evolution of the inferred VDF (velocity dispersion function). VDF is similar to z~0 at z~0.5. At higher z, number density of galaxies with sigma < 200km/s is lower, but number of high dispersion galaxies is constant or higher. At fixed cumulative number density, the velocity dispersion of galaxies increase with time by a factor of 1.4 from z=1.5 to 0. Dispersion of galaxies with lower number density are approximately constant, or decrease with time.
* The evolution of velocity dispersion is such that: it was higher at z>0.5 to 1.5 than it is today.
* This (the velocity dispersion distribution) must be related to galaxy merger rates.
* I didn't quite get everything the abstract is trying to say.
1107.0965
Intergalactic gas in groups of galaxies: implications for dwarf spheroidal formation and the missing baryons problem
Freeland, Wilcots
Use bent-double radio sources to probe intragroup medium gas densities in galaxy groups (assuming that their jets are bent by ram-pressure). Probe IGM density at large radii where x-ray detection is limited by the cool temperature of gas. Gas density at 10e-3 to 10e-4 at 15-700 kpc from group center. Rough estimate of total baryonic mass consistent with missing baryons in the IGM of galaxy groups (??). Neutral gas in dwarf galaxies will easily be stripped in these groups. In combination with tides, even low gas density groups like the Local Group can still generate dwarf spheroidals like Leo T, when combined with tides.
* Probing IGM gas density which allows Hi gas stripping from low mass systems like dwarf galaxies.
1107.0317
Galaxy structure and mode of star formation in the SFR-Mass plane from z~2.5 to 0.1
Wuyts et al
HST observation of high z galaxy morphology and Herschel-calibrated SFR indicators show that by z~2.5, the SFR-galaxy structure correlation is already in place. Some exception for high SFR objects, where a rapid build-up of the central mass concentration is implied in these outliers. Challenge for strict halo mass quenching, if stellar and halo mass follow a one-to-one relation, due to coexistence of quiescent, moderately and highly star-forming systems over an order of magnitude or more in stellar mass. At each mass and redshift, those on the main sequence have the largest size (stellar extent?). Rate of size growth corresponds with sSFR.
* Hmm, complicated information.
1107.1254
Early black holes in cosmological simulations: luminosity functions and clustering behaviour
DeGraf, Di Matteo, Khandai, Croft, Lopez, Springel
According to new hydro simulation MassiveBlack, the high-z (z>5) quasar luminosity function (QLF) is consistent with an evolution following that of a halo mass function. (DM halo distribution provided--it seems separately?) Exception: at high mass end, the quasar luminosity unusually brighter than observed (at z=6~7) due to cooling flow feeding quasar. Predict number density of quasars in upcoming surveys: CANDELS (119pm28/87pm28 for wide/deep at z=5-6, 19/18 at z=6-7, 1.7/1.5 at z=7-8). Quasar clustering: consistent with current constraints for SDSS (r_0 ~ 17 Mpc/h at z=4 for quasars above m_i = 20.2) and grows with z up to z=6 (r_0~22 Mpc/h). Clustering gets somewhat stronger at higher luminosities (since then they are found at high mass halos).
1107.1258
Space reddenings for fifteen Galactic cepheids
Turner, MacLellan, Henden, Berdnikov
Space reddening derived from BVRIc data for AF-type stars in the vicinities of the 15 Galactic variables, in conjunction with 2MASS reddenings for BAF-type stars in the same fields. Some cepheids have large color excesses. AF dwarf BFRIc color relation modified slightly.
* I don't know what a AF type star is.
1107.1280
SDSS J133401.39+331534.3: A new subarcsecond gravitaionally lensed quasar
Rusu, Oguri, ...Kayo, Iye, ... et al.
Quasar at z=2.426, 0.833" separation. Lensing galaxy probably at 0.557, from absorption lines of quasar and the color of the galaxy. Used Subaru AO188 with laser guide star (!). Nearby galaxy 4" apart probably affect the lens potential.
* subarcsecond-separation SL image from ground using AO!
1107.1350
Transformations between WISE, 2MASS, SDSS and BVRI photometric systems: I. Transformation equations for dwarfs
Bilir et al.
* Here I believe "dwarfs" mean main sequence stars.
Color transformations for conversion of W1, W2 mags from WISE, to Johnson-Cousins' BRVI, SDSS (gri), and 2MASS (JHK_s) photometric systems for dwarfs. W3/W4 had insufficient S/N. Used 825 dwarf samples compared to WISE early data release. (1) data dereddened, (2) remove giants from sample, (3) select data according to data quality, (4) derive transforms for subsamples of different metallicity range, (5) transformations are two color dependent (?). Can be used for space density evaluation for the Galactic discs (thin and thick) at distances larger than 2MASS JHK_s photometry.
1107.1395
Photometric redshift requirements for lens galaxies in gg lensing analysis
Nakajima, Mandelbaum, Seljak, Cohn, Reyes, Cool
Calculate bias in lensing mass calibration, absolute magnitude, stellar mass estimates for SDSS DR8 photometry. Photo-z quality is sigma_{dz/(1+z)} ~0.1. Lensing calibration can achieve 2/4 % accuracy for src only/ lens-src photoz.
1107.1444
Theoretical spectra of the Am CVn Binary Systems SDSS J0926+3624: Effects of irradiation onto the donor stars
Sengupta, Taam
Compare synthetic spectra (from stellar atmosphere models with accretion disks around the primary) to observed (SDSS optical). Use eclipsing to infer photometric flux of primary star; obtain upper limit to distance based on absolute magnitude estimated from simulation. Shown that the spectrum of a cool donor can exhibit emission lines due to irradiation from a hot primary, and while contribution from disk dominates, the emission line should be observable (in IR).
1107.1484
The hyperactive L Dwarf 2MASS J13153094-2649513: Continued emission and a brown dwarf companion
Burgasser, Sitarski, Gelino, Logsdon, Perrin
High propermotion, unusually active (many non-thermal emission with H I Balmer, Na I and K I emission lines). AO imaging at Keck indicates presence of low-temperature companion separated by 0.34". It's the 2nd most extreme flux ratio very low-mass binary to date. Separation is about 6.6AU--no mass exchange or magnetospheric interaction which fuels the emission line, but probably chromospheric in nature--in which strong magnetic fields are maintained by relatively old and massive ultracool dwarfs.
1107.1488
Structural analysis of the SDSS cosmic web I. Nonlinear density field reconstructions
Platen, Weygaert, Jones, Vegter, Aragon-Calvo
Three reconstruction techniques to analyze and investigate weblike features and geometries in a discrete distribution of objects: investigated for void detection accuracy. Delaunay Tessallation is most accurate in void detection, while also computationally far less demanding. Void recovery rate poor on <3Mpc/h scales for any method.
0912.0511
Angular correlation functions of 1.5 million LRG's: clustering evolution and a search for BAO
Swangwit, Shanks, Abdalla... Ross, et al.
Angular correlation fucion from photometric samples comprising 1.5M LRGs. Three subsamples at z~0.35, 0.55, and 0.7. Not a single power-law, but a break seen at ~1Mpc/h, consistent with halo occupation models. Clustering amplitude increases with LRG luminosity, in accordance with the simple high peaks model. Evolution slightly faster for r<1 Mpc/h. In order to explain the small scale clustering evolution, 2-3 percent per Gyr of the LRGs is required to merge.
* doesn't sound like they found LRG BAO.
1010.3017
Extended Lyman-alpha emission around star-forming galaxies
Zheng, Cen, Weinberg, Trac, Miralda-Escude
Ly-alpha photons may be resonantly scattered by H I atoms in the intergalactic media, increasing the extent of galaxy's Lya emission. Present Lya extent predictions that can be observed in stacked images of Lya emitters and LBGs. Average surface brightness has central cusp, flattens to a plateau at ~0.2Mpc comoving, then steepens beyond an outer characteristic scale of 1 Mpc. Comparison to observation will test radiative transfer models of emission from LAEs and LBGs; and will open a new window on the circumgalactic environment of high-z star forming galaxies.
1104.5230
A super-earth transiting a naked-eye star
Winn, et al.
* I think I've read this one before.
Transit period is 0.74 days (!) around a Sun-like star and x8 earth-mass planet. Must be very hot. Density of planet similar to earth, so it must have lighter elements in addition to the rock-iron core. Some anomaly in the transit curve, which cannot be explained by eclipsing face.
1105.1873
Wide binaries as critical test of classical gravity
Hernandez, Jiminez, Allen
Change of gravity at acceleration scales a < a0. Test using binary stars--for 1 M_sun systems, the acceleration drops below a0 at 7000 AU. Need wide binaries to test them. Use Hipparcos with high S/N, then with SDSS of low S/N. Results show upper limit to the relative velocities in wide binaries, independent of separation for over 3 orders of magnitude, in analogy with flat rotation cures in the same a<a0 acceleration regime. Strongly suggestive of breakdown of Kepler's third law below a0 scales.
* Hmm.
1107.0729
Cencelling out systematic uncertainties
Norena, verde, Jiminez, Pena-Garay, Gomez
A method to minimize/cancel out the nuisance parameters affecting a measurement. For BAO: by combining radial and angular measurements in order to completely eliminate the dependence on the sound horizon at radiation drag. For SNIa: Uncertainty in the luminosity distance from metallicity dependence greatly reduced. Cosmic clocks: particular combination of observables nearly removes the metallicity dependence of the galaxy, removeing the age-metallicity degeneracy in stellar populations.
* How exactly does this work? It doesn't exactly say in the abstract.
1107.0908
Solar magnetic fields
Hood, Hughes
Review: intorduction to the generation and evolution of the sun's magnetic field; observational and theoretical. 11 year cycle = large-scale solar dynamo; current ideas on the mechanism presented. Eruption of the global coronal magnetic field can impact the Earth's environment--this can be modeled to high degree of accuracy. Modeling show continual evolution of small-scale magnetic field, presumably produced by small-scale dynamo action in the solar interior. Sunspots = natural consequence of large-scale dynamo; emerge and disperse over a period of several days; simulations help determine physical processes. Interaction of these emerging fields with pre-existing coronal field result in a variety of dynamic phenomena.
* cool. It's 44 pages of review.
1107.0465
Distribution of high mass x-ray binaries in the milky way
Coleiro, Chaty
INTEGRAL satellite observing the sky at high energy: x4 number of supergiant x-ray binaries; distribution; correlation with the distribution of SF complexes in the galaxy. HMXB are clustered with SFCs; typical size of 0.3 kpc and characteristic distance between clusters of 1.7 kpc.
* BH distribution related to SF.
1107.0516
Evolution of the CMB power spectrum across WMAP data releases: A nonparametric analysis
Aghamousa, Arjunwadkar, Souradeep
Non-parametrically (data only) determine: (1) angular power spectrum (2) How well is LCDM supported by a data-driven analysis? (3) realistic uncertainties on peak/dip locations and heights. Non-parametric results very close to LCDM parametric fits where data are sufficiently precise (define "sufficiently precise"?). Non-parametric fit can indicate non-compatibility to a given model. The low-l upturn in the CMB angular power spectrum cannot be ruled out at any confidence level in excess of about 10%.
1107.0517
Formation of galactic nuclei with multiple supermassive black holes at high redshifts
Kulkarni, Loeb
Formation of multiple SMBH in gas-poor nuclei due to high merger rate of galaxies at high-z examined: calculate the relative likelihood of binary, triple and quadruple SMBH systems. COnsider timescales of relevant processes and combine merger trees with N-body simulations for dynamics of stars and SMBH in galactic nuclei. Halos of 1e14 Msun today were at 5e11Msun at z=6, which hosted a single galaxy at this time. At 2<z<6, the galaxies with this halo size is expected to contain more than two SMBH's. For larger present-day halos (1e15 Msun), this fraction is 60%. Multiple SMBH potentially explains mass deficiencies observed in the cores of massive elliptical galaxies---up to x5 the mass of their central BHs. Multiple SMBH also leads to enhanced rate of tidal disruption of stars, modified gravitational wave signals, and slingshot ejection of SMBH at speeds in excess of 2000km/s.
1107.0601
The AMIGA sample of isolated galaxies: VIII. the rate of asymmetric H I profiles in spiral galaxies
Espada, Verdes-Montenegro, Huchtmeier, Sulentic, Verley, Leon, Sabater
Study of H I profile asymmetries in a sample of isolated galaxies in the local Universe---which can serve as a zero-point for galaxy interaction diagnostiic for non-isolated galaxies. Search for correlation between H I asymmetry and their environments, as well as their optical and IR properties. N=166 galaxies with high S/N in AMIGA project. Asymmetry described by a Gaussian model, whose width is sigma=0.13 including instrument errors. Lack of correlation between H I asymmetry and tidal force (1-1 interaction) and neighbor galaxy density. But field galaxy samples show wider distribution and deviate from a Gaussian curve. Spiral arm strength is inversely correlated with the H I asymmetry (interesting). Excess of FIR luminous galaxies with larger H I asymmetries that may be spirals associated with hidden accretion events.
1107.0682
Violation of the rotational invariance in the CMB bispectrum
Shiraishi, Yokoyama
Quantum fluctuation of a vector field producing primordial non-Gaussianity as a statistical anisotropy on the CMB bispectrum, violating rotational invariance. Detection would be awesome.
* right.
1107.0318
Chern-Simons Inflation and Baryogensis
Alexander, Marciano, Spergel
* Chern-Simons theory: 3-D topological quantum field theory (QFT which incorporates topological invariants) of Schwarz type (correlation functions computed by the path integral--the path integral measure and quantum field obesrvables are explicitly independent of the metric); action is proportional to the integral of the Chern-Simons 3-form.
* Sakharov condition: 3 necessary conditions that a baryon-generating interaction must satisfy to produce matter and antimatter at different rates. (1) Baryon number B violation. (2) C-symmetry and CP-symmetry violation. (3) Interactions out of thermal equilibrium.
Model of inflation where the C-S interaction and vector fields plays a role can self-consistently satisfy the Sakharov condition. Calculate the net baryon asymmetry index (gauge configuration necessary for inflation; chiral anomaly). Inflation begins with interacting gauge fields and fermions that interact through gravity and C-S term. Affects superhorizon scales. Phase-correlation and amplification of gauge field produces conditions to maintain more than 60 e-fields of inflation. Eventually the gauge field dissipates by producing the observed baryon asymmetry through the chiral anomaly, and inflation ends.
* waterproof theory?
* chiral anomaly: the anomalous non-conservation of a chiral current. In some theories of fermions with chiral symmetry, the quantization may lead to the breaking of this (global) chiral symmetry. In this case, the charge associated with the chiral symmetry is not conserved.
* Chiral asymmetry related to CP violation?
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