1206.3303
Characterization of exoplanets from their formation II: the planetary mass-radius relationship
Mordasini, et al
Extend formation model into a coupled formation and evolution model, to predict observables (luminosity, radii, radial velocity). Calculate internal structure of solid core and raiogenic heating; imrpove protoplanetary disk model; population synthesis. Predict M-R relation, for a given mass, a range of radii possible; matches observations. Synthetic radius distribution has strong increase towards small R, and a second lower local maximum at ~1 Jovian radius (due to radii are nearly independent of mass for giant planets). Kepler should be able to find this peak.
1206.3305
Halo statistics in non-Gaussian cosmologies: the collapsed fraction, conditional mass function, and halo bias from the path-integral excursion set method
D'Aloisio, Zhang, Jeong, Shapiro
New analytical method (path-integral extension of excursion set formalism) which recovers Desjacques+ (2011) non-Gaussianity universe halo bias (both scale-dependent and -independent), to the leading order in perturbative calculation. Next-to-leading order can lead to marked differences in halo bias.
1206.3306
Non-Gaussianity and excursion set theory: halo bias
Adshead, Baxter, Dodelson, Lidz
[very similar topic as above] Impact of primordial non-Gaussianity during inflation on the halo bias using excursion set theory; bias scales as k^-2 on large scales; identify approximations, and correct it. Also solve for non-spherical halo, for which the collapse threshold is scale dependent.
1206.3308
Stellar populations of UV-selected active galactic nuclei host galaxies at z~2-3
Hainline, Shapley, Greene, Steidel, Reddy, Erb
Use SPS to analyze 33 UV-selected narrow-line AGN galaxies at z~2-3. Quantify contribution of AGN to host galaxy SEDs: have photometric coverage from UV to NIR (rest frame) photometry for 11 AGNs; model with linear combination of SP and AGN template. AGNs have higher masses and SFRs than the full non-active sample, but their stellar population properties are consistent with those of the mass-selected sample, suggesting that the presence of an AGN is not connected with the cessation of SF activity in SF galaxies at z~2-3; Correlation between M_BH and galaxy stellar mass already in place.
1206.3314
New constraints on the galactic halo magnetic field using rotation measures of extragalactic sources towards the outer galaxy
Mao et al
Study halo B-field of MW disk from Faraday rotation toward 641 polarized extragalactic radio sources within 30 digs of Galactic plane. For |b| < 15 digs, RM distribution symmetric about the Galactic plane; consistent with a disk field in the Perseus arm of even parity across the Galactic mid-plane. For 15<|b|<30, median rotation measures of -15pm4 rad/m^2 and -62 pm 5 rad/m^2 in the northern and southern Galactic hemispheres, respectively. Suggests halo B-field toward the outer Galaxy does not reverse direction across the mid-plane (assuming RM distribution is a signature of large-scale field parallel to the Galactic plane). RMs become more negative at larger |b| (trend); consistent with azimuthal B-field of 2 microGauss (7microGauss) at height 0.8-2 kpc above (below) the Galactic plane between the local and Perseus spiral arm. MW could posses spiral-like halo B-fields similar to those observed in M51.
1206.3322
Galaxy rotation curves from a fourth order gravity
Mishra, Singh
Fourth order modification of the Poisson equation which yields the same Yukawa type modification of Newtonian gravity as STVG, which can explain flat galaxy rotation curves.
1206.3331
Fragmentation in the massive star-forming region IRAS 19410+2336
Rodon, Beuther, Schilke
The core mass functions (CMFs) of low-mass SF regions are found to resemble the shape of the IMF; similarly for dust clumps in high-mass SF region, although at spatial scales of clusters that do not resolve the substructure. IRAS 19410 has resolution to 2500 AU, resolving substructure. Observe H2CO and CH3CN. Detect CMF with power law index b=-2.3pm0.2. Cannot unambiguously differentiate protostellar and prestellar cores, the derived CMF is not prestellar. Need more data (e.g., ALMA).
1206.3343
Polarisation properties of Milky-Way-like galaxies
Sun, Reich
Study the polarization properties, B-field strength, and synchrotron emission scale-height of MW-like galaxies in comparison with other spiral galaxies, using 3D-emission model.
1206.3389
Spectral and polarization study of the double relics in Abell 3376 using the GMRT and the VLA
Kale, Dwarakanath, Bagchi, Paul
Double radio relics in galaxy clusters are rare phenomena that trace shocks in the outskirts of merging galaxy clusters. Spectral and polarization study of these relics reveals a high degree of polarization (30%) and aligned B-field vectors in the eastern relic; highly polarized (>60%) filamentary radio source of 300kpc size found; spectral indicies indicate mach range of 2.2 to 3.3.
1206.3412
A seven square degrees survey for galaxy-scale gravitational lenses with the HST imaging archive
Pawase, Faure, Courbin, Kokotanekova, Meylan
Visual search for [probably strong] lens in HST images (7 sq deg). Goal: provde a sample of lenses with a broad range of different morphologies and lens-source brightness contrast in order to design and train future automated lens finders in view of all-sky surveys. Criteria is purely morphological (no color or z info). Conservative, so sample is nearly pure, but incomplete. Find 49 new candidates, 16 secure, 21 "good", 12 "compatible". Dataset is heterogenous in depth and spans a broad range of galactic latitudes (insensitive to cosmic variance). Euclid (15000 sq deg) can find 60000 galaxy-scale SL down to I=24.5 (10sig) or 25.8 (3sig).
1206.3448
What are the R Coronae Borealis stars?
Clayton
RCB stars are rare H-deficient, C-rich super giants, known for their spectacular declines in brightness at irregular intervals. Two suggested evolutionary scenarios: a double degenerate merger of 2 WDs, or a final He shell flash in a planetary nebula central star. RCB stars have large amounts of 18O tilts to merger scenario: then RCB stars are the low-mass analogs of SNe Ia. RCB star number count prediction consistent with He/CO WD mergers, but only about 65 of the predicted 5000 RCB stars in the Galaxy have been discovered.
1206.3458
THe gas-phase metallicity of central and satellite galaxies in the SDSS
Pasquali, Gallazzi, van den Bosch
Study how the gas-phase metallicities of SF galaxies depend on environment: find satellite and central galaxies follow a qualitatively similar M*-gas-phase metallicity relation. But satellites have higher gas-phase metallicities than equally massive centrals, with the difference increasing with decreasing M*. Find: gas-phase metallicity of satellites increases with halo mass at fixed stellar mass. Not due to stellar mass stripping or past SF history of these galaxies, but probably from a combination of 3 environmental effects: (i) strangulations (otherwise ISM metallicity would dilute), (ii) ram-pressure stripping of outer gas disk (inhibit radial inflows of low-metallicity gas, and (iii) external pressure provided by the hot gas of the host halo, which prevents metal-enriched outflows from escaping the galaxies.
1206.3461
Avoiding selection bias : a unified treatment of thresholded data
Messenger, Veitch
Selection bias : naturally avoided by using the full information from the search, considering both the selected data and the ignorance of the data that are thrown away, and considering all relevant signal and noise models. This approach produces unbiased estimates of parameters even in the presence of false alarms and incomplete data.
Galaxy rotation curves from a fourth order gravity
Mishra, Singh
Fourth order modification of the Poisson equation which yields the same Yukawa type modification of Newtonian gravity as STVG, which can explain flat galaxy rotation curves.
1206.3331
Fragmentation in the massive star-forming region IRAS 19410+2336
Rodon, Beuther, Schilke
The core mass functions (CMFs) of low-mass SF regions are found to resemble the shape of the IMF; similarly for dust clumps in high-mass SF region, although at spatial scales of clusters that do not resolve the substructure. IRAS 19410 has resolution to 2500 AU, resolving substructure. Observe H2CO and CH3CN. Detect CMF with power law index b=-2.3pm0.2. Cannot unambiguously differentiate protostellar and prestellar cores, the derived CMF is not prestellar. Need more data (e.g., ALMA).
1206.3343
Polarisation properties of Milky-Way-like galaxies
Sun, Reich
Study the polarization properties, B-field strength, and synchrotron emission scale-height of MW-like galaxies in comparison with other spiral galaxies, using 3D-emission model.
1206.3389
Spectral and polarization study of the double relics in Abell 3376 using the GMRT and the VLA
Kale, Dwarakanath, Bagchi, Paul
Double radio relics in galaxy clusters are rare phenomena that trace shocks in the outskirts of merging galaxy clusters. Spectral and polarization study of these relics reveals a high degree of polarization (30%) and aligned B-field vectors in the eastern relic; highly polarized (>60%) filamentary radio source of 300kpc size found; spectral indicies indicate mach range of 2.2 to 3.3.
1206.3412
A seven square degrees survey for galaxy-scale gravitational lenses with the HST imaging archive
Pawase, Faure, Courbin, Kokotanekova, Meylan
Visual search for [probably strong] lens in HST images (7 sq deg). Goal: provde a sample of lenses with a broad range of different morphologies and lens-source brightness contrast in order to design and train future automated lens finders in view of all-sky surveys. Criteria is purely morphological (no color or z info). Conservative, so sample is nearly pure, but incomplete. Find 49 new candidates, 16 secure, 21 "good", 12 "compatible". Dataset is heterogenous in depth and spans a broad range of galactic latitudes (insensitive to cosmic variance). Euclid (15000 sq deg) can find 60000 galaxy-scale SL down to I=24.5 (10sig) or 25.8 (3sig).
1206.3448
What are the R Coronae Borealis stars?
Clayton
RCB stars are rare H-deficient, C-rich super giants, known for their spectacular declines in brightness at irregular intervals. Two suggested evolutionary scenarios: a double degenerate merger of 2 WDs, or a final He shell flash in a planetary nebula central star. RCB stars have large amounts of 18O tilts to merger scenario: then RCB stars are the low-mass analogs of SNe Ia. RCB star number count prediction consistent with He/CO WD mergers, but only about 65 of the predicted 5000 RCB stars in the Galaxy have been discovered.
1206.3458
THe gas-phase metallicity of central and satellite galaxies in the SDSS
Pasquali, Gallazzi, van den Bosch
Study how the gas-phase metallicities of SF galaxies depend on environment: find satellite and central galaxies follow a qualitatively similar M*-gas-phase metallicity relation. But satellites have higher gas-phase metallicities than equally massive centrals, with the difference increasing with decreasing M*. Find: gas-phase metallicity of satellites increases with halo mass at fixed stellar mass. Not due to stellar mass stripping or past SF history of these galaxies, but probably from a combination of 3 environmental effects: (i) strangulations (otherwise ISM metallicity would dilute), (ii) ram-pressure stripping of outer gas disk (inhibit radial inflows of low-metallicity gas, and (iii) external pressure provided by the hot gas of the host halo, which prevents metal-enriched outflows from escaping the galaxies.
1206.3461
Avoiding selection bias : a unified treatment of thresholded data
Messenger, Veitch
Selection bias : naturally avoided by using the full information from the search, considering both the selected data and the ignorance of the data that are thrown away, and considering all relevant signal and noise models. This approach produces unbiased estimates of parameters even in the presence of false alarms and incomplete data.
1206.3484
How not to build Tatooine: the difficulty of in situ formation of circumbinary planets Kepler 16b, Kepler 34b, and Kepler 35b
Paardekooper et al
These circumbinary planets were liekly assembled further out in the disk and migrated inward to their current location, since planetesimal accretion is found to be very inefficient.
1206.3506
Peaks theory and the excursion set approach
Paranjape, Sheth
Describe a model of DM halo abundances and clustering which combines the two most widely used approaches: that based on peaks and the other based on excursion sets. Seeks to account for correlations between steps in the walk as well as correlations between walks. First show how the excursion set and peaks models can be written in the same formalism ...
1206.3540
Guild by association: finding cosmic ray sources using hierarchical Bayesian clustering
Soiaporn et al
UHE CR of E>5e19 eV (1e7 times more energetic than that produced at LHC). What phenomenon accelerates particles (atomic nuclei) to such high energies? What sort of nuclei are energized? Sensitivity to B-field makes them potential probes of B-fields. Develop a Bayesian model that can be used to compare different association models between the CRs and source population.
1206.3545
A new method for the Alcock-Paczynski test
Montanari, Durrer
Argue: observation can only measure C_l(z1, z2) and the corresponding xi(theta, z1, z2); they contain the full 3d info. Determine xi (gal) at linear order in perturbation theory. z-space distortion taken into account for arbitrary angular and z separations. How to measure H(z) and the D_A(z) separately from these correlation functions and perform an AP test.
How not to build Tatooine: the difficulty of in situ formation of circumbinary planets Kepler 16b, Kepler 34b, and Kepler 35b
Paardekooper et al
These circumbinary planets were liekly assembled further out in the disk and migrated inward to their current location, since planetesimal accretion is found to be very inefficient.
1206.3506
Peaks theory and the excursion set approach
Paranjape, Sheth
Describe a model of DM halo abundances and clustering which combines the two most widely used approaches: that based on peaks and the other based on excursion sets. Seeks to account for correlations between steps in the walk as well as correlations between walks. First show how the excursion set and peaks models can be written in the same formalism ...
1206.3540
Guild by association: finding cosmic ray sources using hierarchical Bayesian clustering
Soiaporn et al
UHE CR of E>5e19 eV (1e7 times more energetic than that produced at LHC). What phenomenon accelerates particles (atomic nuclei) to such high energies? What sort of nuclei are energized? Sensitivity to B-field makes them potential probes of B-fields. Develop a Bayesian model that can be used to compare different association models between the CRs and source population.
1206.3545
A new method for the Alcock-Paczynski test
Montanari, Durrer
Argue: observation can only measure C_l(z1, z2) and the corresponding xi(theta, z1, z2); they contain the full 3d info. Determine xi (gal) at linear order in perturbation theory. z-space distortion taken into account for arbitrary angular and z separations. How to measure H(z) and the D_A(z) separately from these correlation functions and perform an AP test.
[Mon **/37] Jun 18
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