1203.4228
Hot gas in galaxy groups: recent observations
Sun
Hot gas in groups and its scaling relations (X-ray luminosity, entropy, gas fraction, baryon fraction and metal abundance). Compared to clusters, groups have lower fraction of hot gas around the center (<r_2500), but may have a comparable gals fraction at large radii (out to r_500). Better constraints on gas and baryons require different selection functions and deeper observations of r_500 region. Hot gas in groups is also iron poor at large radii; Fe content correlates with the group mass, in contrast to the trend of stellar mass fraction. X-ray cool cores in groups and their difference from cluster cool cores, radio AGN heating in groups, and the cold gas in group cool cores. Group cool cores are sensitive to AGN feedback and hence test the AGN feedback model and the multiphase cool core models.
1203.4229
GNOMOS: The Gemini NIR-Optical Multi Object Spectrograph
Schiavon et al
New Gemini instrument for multi-object, medium resolution, high-throughput spectrograph, simultaneously covering optical and near-IR.
1203.4230
Searching for gamma-ray blazar candidates among the unidentified INTEGRAL sources
Massaro, Paggi, D'Abrusco, Tosti
Another paper about finding IR counterpart to gamma-ray sources via blazar connection; 113 unidentified INTEGRAL sources (UISs), of which 86 were in WISE IR survey; found 18 of them to appear to have gamma-ray blazar candidate within positional error. SWIFT data on 10/18 candidates; 7/10 are clearly detected in soft X-ray and optical/UV. Cannot confirm associations between UISs and selected gamma-ray blazar candidates, due to the discrepancies between the INTEGRAL and the soft X-ray spectra.
1203.4231
Low CO luminosities in dwarf galaxies
Schruba et al
Present CO 2-1 emission of SF disks of 16 nearby dwarf galaxies from IRAOM HERACLES; 13" resolution (250pc at 4Mpc); galaxy has 10-1000 resolution elements. Stack for sensitive search of CO emission. 5 dwarfs have CO emission; other 11 undetected in CO even when stacked over IR-bright regions. Study scaling relations of L_CO with M_B and metallicity. Find: dwarfs with metallicities of Z~0.1-0.5 Z_sun have L_CO 1e2-4 smaller than spirals ; L_CO/L_B is 10-100x smaller. Comparison with tracers of SF (FUV and 24um) show: L_CO per unit SFR is 10-100x smaller in dwarfs. Dwarfs form stars much more efficiently is a possible interpretation: but argue, low L_CO/SFR ratio is due to significant changes to the CO-to-H2 conversion factor in low metallicity environments. Assume constant H2 depletion time of 1.8 Gyr (true for nearby spirals) implies conversion factor alpha_CO for dwarfs with low Z are more than 10x higher than nose find in solar metallicity spirals. Significant increase of alpha_CO at low metallicity is consistent with previous studies, in particular with dust emission - H2 correlation studies. Difficult to parameterize metallicity dependence of alpha_CO; CO is increasingly difficult to detect at lower metallicity.
1203.4232
Improved limits on short-wavelength gravitational waves from the cosmic microwave background
Sendra, Smith
* Tristan!
CMB fluctuations affected by total radiation density around the time of decoupling where neutrinos comprised a fraction of the radiative energy, but there could also be a contribution from primordial gravitational waves with frequencies greater than 1e-15 Hz. If this cosmological gravitational wave background (CGWB) were produced under adiabatic initial conditions, its effects on the CMB and matter power spectrum would mimic massless non-interacting neutrinos.
1203.4560
Planetary and other short binary microlensing events from the MOA short event analysis
Bennett, et al
4 candidate short duration binary microlensing events: free-floating planets. 3 are microlensing events; 4th likely stellar variability. 3 lensing signal almost entirely due to brief caustic feature with little or no lensing attributable mainly to the lens primary. One is due to a planet where the host is detected through binary microlensing effects; mass ratio is 5e-3, separation 2.1 [what are the units?], large for a microlensing event; mass of 3.7 M_Jup, and 0.75 Msun, semi major axis of a=8.3 AU; most massive planet found via microlensing. Scarcity of such wide separation planets has implications for interpretation of the isolated planetary mass objects found by this analysis. If these planets are actually bound in wide orbits around host stars, then likely that the median orbital semi-major axis is >30AU.
1203.4561
The dynamics and metallicity distribution of the distant deaf galaxy VV124
Kirby, Cohen, Bellazzini
Isolated dwarf irregular/dwarf spheroidal (dIrr/dSph) transition-type galaxy at a distance of 1.36 Mpc. Stellar disk, inconsistent radial velocities for different components of the galaxy. Individual red giants observed with Keck/DEIMOS spectrograph; validated members based on positions in the color-magnitude diagram, radial velocities, and spectral features. Sapmle contains 67 members; average radial velocity is -30 km/s (agrees with HI gas measurements); velocity dispersion Gaussian, inside radius of 1.5 kpc. Outside this radius, dispersion is 10 km/s (M_1/2=1e7 Msun, M/L_V=5.2 Msun/Lsun, measured to half light radius, has DM). Metallicity distribution from FeI lines; avg metallicity is -1.14, consistent with dSph.
1203.4566
EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions
Surcis, Vlemmings, van Langevelde, Kramer
Measured Zeeman-splitting in 154 CH3OH masers; fractional liear polarization (1-10%) detected towards 55 masers; linear polarization vectors well-ordered in all the massive SF regions. Agrees well with sub millimeter wavelength dust observation (low resolution B-field).
1203.4567
Cosmology when living near the great attractor
Valkenburg, Bjaelde
If we live in the vicinity of the Great Attractor, the age of the universe inferred from the local expansion rate can be off by 3%. Study the effect of living inside or near a massive over density has on cosmological parameters induced from observations of SNe, H) and CMB. Compare results to those for an observed in a perfectly homogeneous LCDM universe. Find that inverted value for H0 changes by around 3% if we live inside a massive over density such as the Great Attractor.
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