1204.0782
Physical properties of Lyman-alpha emitters at z~0.3 from UV-to-FIR measurements
Oteo, et al
Study low-z Ly-a emitters for clues to the high-z analogues. At z~0.3, LAEs are bright enough to be detected over the whole EM spectrum; can be better studied than at high-z. Examine UV and IR emission, dust attenuation, SFR and morphology of a sample of 23 GALEX-discovered SF LAEs with space-based UV to FIR data (GALEX, ACS, PACS and MIPS). Ly-a galaxies are (i) less dusty, (ii) have slightly higher SFR, (iii) have bluer UV continuum slopes, and (iv) are much smaller than other galaxies that do not exhibit Ly-a emission in their spectrum. [Hmm, maybe their metallicities are lower too?] LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at z~0.3. The comparison of results with those obtained at higher redshifts indicates that either the Ly-a technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.
1204.0784
H2D+ in the high mass star-forming region Cygnus-X
Pillai, Caselli, Kauffmann, Zhang, Thompson, Lis
H2D+ is a primary ion which dominates the gas-phase chemistry of cold dense gas; probes the earliest, pre stellar phase of star formation. But distribution and abundance still not well understood. Present observational results in Cygnus-X with JCMT and SMA. Very extended
(<34kAU diameter) weak structures in H2D+, distinctly offset from embedded protostars; not associated with a dust continuum or N2D+ peak. Discovered 5 massive cold dense gas that was undetected with previous molecular line and dust continuum surveys of the region. Structure of core model needs to be refined: neither dust continuum nor emission in tracers like N2D+ can provide a complete census of the total pre stellar gas in such regions.
1204.0786
The galaxy-dark matter connection: a cosmological perspective
More, van den Bosch, Cacciato, More, Mo, Yang
Constrain both cosmological parameters and HOD from galaxy observations. Galaxies are a biased tracer of mass distribution (bias unknown). By marginalizing over HOD, you marginalize uncertainties regarding galaxy bias, and constrain galaxy-DM connection (marginalized over cosmology). Constrain abundance, clustering and gg-lensing signal described by combination of SAM, analytical halo model and conditional luminosity function. Use Fisher to gauge complementarity. Present results from SDSS. Results complementary and consistent with WMAP7.
1204.0787
Nucleosynthesis and the inhomogeneous chemical evolution of the Carina dwarf galaxy
Venn et al
Chemistry of metal-poor stars in Carina is not similar to those in the Galaxy, most of the other dSphs, or the UFDs, and suggests that Carina may be a the critical mass where some chemical enrichment events are lost through SN II driven winds.
1204.0788
Searching for new OH megamasers out to z>1
Willett
Search for 18cm OH megamaser (OHM) emission with Green Bank; target 121 ULIRGS at 0.09<z<1.5. 9 new detections of OHMs reported with z<0.25. Losses from FRI result in OHM detection being significantly lower than expected for galaxies with L_IR>1e12 Lsun. Calculate OH luminosity function, Phi propto L_OH^-0.66, in agreement with previous results.
1204.0793
Why and when is internally-driven AGN feedback energetically favored?
Pope
To ensure that the Gibbs free energy always decreases, a galaxy will necessarily flip between these two states, experiencing episodes of heating and cooling. Observable appearance of galaxy growth being regulated by AGN feedback. Same mechanism also provides explanation for why strong AGN feedback occurs more frequently in cool-core galaxy clusters than in non cool core clusters.
1204.0795
Predictions for the CO emission of galaxies from a coupled simulation of galaxy formation and photon dominated regions
Lagos et al
Combine GALFORM with UCL_PDR (Photon dominated region code) to study the rotational transitions of 12CO in galaxies from z=0 to 6 in LCDM. GALFORM predicts H2 and HI gas contents of galaxies using pressure-based empirical SF relation. From the predicted H2 mass and the conditions in the ISM, estimate CO emission by applying UCL_PDR model. Find: deviations from the MW CO-H2 conversion factor come mainly from variations in metallicity, and in the average gas and SF rate surface densities. Local universe predictions in good agreement. Predicts little evolution in the CO-to-IR luminosity ratio for different CO transitions, in good agreement with observations up to z~5. Potential of using color selected samples of high-z SF galaxies to characterize the evolution of the cold gas mass in galaxies through observations in ALMA.
1204.0804
The stellar-subhalo mass relation of satellite galaxies
Rodriguez-Puebla, Drory, Avila-Reese
Use abundance matching technique (AMT) to infer satellite-subhalo and central-halo mass relations (MRs) of galaxies, as well as the corresponding satellite conditional mass functions (CMFs). Assuming same MRs for centrals and satellites leads to disagreement with observations. If satellite-subhalo MRs constrained with AMT, they are always different from the central-halo MR; the smaller the stellar mass, the less massive is the sub halo of satellites, as compared to the halo of centrals of the same M*.
1204.0806
Milliarcsecond structure of water maser emission in two young high-mass stellar objects associated with methanol masers
Bartkiewicz, Szymczak, van Langevelde
In both targets the main axis of methanol distribution is orthogonal to the water maser distribution; most of water masers appear to trace shocks on a working surface between an outflow/jet and a dense envelope. Some spots are possibly related to the disk-wind interface which is as close as 100-50 AU to the regions of methanol emission.
1204.0812
Improved collision strenghts and line ratios for forbidden [O III] far-infrared and optical lines
Palay, Nahar, Pradhan, Eissner
Usefule temperature-density diagnostics of nebular as well as dust obscured astrophysical sources. Lines are excited primarily by electron impact excitation; but collision strengths for the associated fine structure transitions have not been computed with relativistic effects accounted. Present new calculations, find significant differences of up to 20%. Tabulate to lower temperatures down to 100K, enable determination of physical conditions in cold dusty environments (photo-dissociation regions and ULIR with Herschel). Examine effect on temperature and density sensitive line ratios.
1204.0828
The UBV(RI)c colors of the Sun
Ramirez, et al
Photometric data in the UBV(RI)c system acquired for 80 solar analog stars. Combine data, define colors with 0.01 mag precision, for 112 solar analogs. Atmospheric parameters Teff, log g, and [Fe/H] well known for these objects. B-V=0.653, U-B=0.166, V-R=0.352, V-I=0.702. Whether 112 objects or 10 nearest solar twins, the results are consistent within 1 sigma.
1204.0857
Icecube non-detection of GRBs: constraints on the fireball properties
He, Liu, Wang, Nagataki, Murase, Dai
As the title says. No neutrino stream detected from GRBs.
1204.0933
Multimodality of rich clusters from the SDSS DR8 within the supercluster-void network
Einasto, et al
Study the relation between the mutimodality [what does this mean?] of galaxy clusters drawn from the SDSS DR8 and the environment where they reside. Cluster environment: global luminosity density field, supercluster membership, supercluster morphology. Find: multimode clusters reside in higher density environment than unimodal clusters. Clusters in superclusters have higher probability to have substructure than isolated clusters. Superclusters can be divided into two main morphological types, spiders and filaments. Clusters in spiders have higher probabilities to have substructure and larger peculiar velocities of their main galaxies than clusters in filament superclusters. Most luminous clusters are located in the high-density cores of rich superclusters. Five of seven most luminous clusters, and five of seven most multimode clusters reside in spider-type clusters; 4/7 most unimodal clusters reside in filament-type superclusters. Role of superclusers as high density environment which affects the properties of galaxy systems.
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