1201.0994
The Globular Cluster kinamatics and galaxy dark matter content of NGC 3923
Norris et al
Additional 50 GC and Ultra Compact Dwarf (UCD) candidates spectroscopically confirmed as members, along with 29 GCs. Sample extends to over 6 arcmin (> 6 Re ~ 30 kpc) from the center of NGC 3923, study dynamics of GC system and the DM content of NGC 3923: no rotation, velocity dispersion constant within the uncertainties. Axisymmetric orbit-based models to the GCs and integrated light velocity dispersion profiles demonstrates that a significant increase in the M/L ratio (from M/Lv of 8 to 26) at large galactocentric radii is required to explain these observations. Confirm presence of DM. DM comprises 17.5% of mass within 1Re, 41.2% within 2Re, and 75% within 6.9 Re. Total dynamical mass within this radius is found to be 1.5e12 Msun. Find that this dynamical mass profile is consistently higher than that derived by X-ray observations, by a factor of ~2 (consistent with other studies of large ellipticals).
1201.0999
Spectroscopy of broad line blazars from 1LAC
Shaw et al
The 165 Flat Spectrum Radio Quasars (FSRQs) in the Fermi 1LAC show evidence for non-thermal emission even in the optical, whose degree dpends on the gamma-ray hardness. Also have smaller virial estimates of the (BH) mass than the optical quasar sample, probably largely due to a preferred axial view of the gamma-ray FSRQ and non-isotropic (H/R~0.4) distribution of broad-line velocities. Fermi FSRQ show higher mean Eddington ratios than the optical populations, even after correcting for viewing angle bias. No strong correlation with optical spectral properties with radio flare activity.
1201.1000
Information escaping the correlation hierarchy of the convergence field in the study of cosmological parameters
Carron
From fits to numerical simulations, find that entire hierarchy of moments ceases to provide a complete description of the convergence one-point probability density function for values of the associated matter fluctuations variance as low as 0.1, still in the WL regime. At unit variance, only 5% of Fisher information content is still contained in hierarchy of moments. (Information escapes to higher order moments.) A simple logarithmic mapping makes the moments hierarchy well suited again for parameter extraction, putting 80% of the total information back into the first two and 95% in the first three members.
1201.1002
MOA-2011-BLG-293Lb: a testbed for pure survey microlensing planet detections
Yee, .. Gal-Yam, Bond, ...Gould, MOA collaboration, OGLE collaboration, MicroFUN collaboration
Test pure survey detections as a function of cadence (low cadence means less detection probability for planet microlensing).
1201.1003
Evidence for extended gamma-ray emission from galaxy clusters
Han, Frenk, Eke, Gao, White
3 year Fermi LAT data shows extended gamma-ray emission from the Virgo, Fornax and Coma clusters, within 3 degrees of the center, peaking at GeV scale; cannot be accounted for by known Fermi sources or by galactic and extragalactic BGs. If it's an annihilation emission of SUSY DM particles, then it's particles of mass 20-60 GeV annihilating into the b-bbar channel, or 2-10GeV and >1TeV annihilating into mu-mu final states. Results consistent with Fermi-LAT data from Galactic center. An extended DM annihilation profile dominated by emission from substructures is preferred over a simple point source model. If excess emission due to CR-induced gamma-rays, infer CR level within a factor of 3. The significance of CR component lower than DM component. Set upper limits on cross-section of b-bbar and mu-mu channels in the 3 clusters.
1201.1004
A new candidate for probing Pop II nucleosynthesis with carbon-enhanced damped Lyman-alpha systems
Cooke, Pettini, Murphy
Find a very metal-poor DLA (damped Lya system) at z=3.06 that is modestly C enhanced, with Fe abundance of 1/700 solar ([Fe/H] = -2.84, [C,O/Fe]~+0.6), likely to be result of nucleosynthesis of massive stars. From 17 metal absorption lines, derive 2 sigma upper limit on the DLA's kinetic temperature. Pop III, as well as high-mass Pop II stars match the abundance pattern well. Discuss limitation between distinguishing the two.
1201.1005
The grand cosmic web of the first stars
Visbal, Barkana, Fialkov, Tseliakhovich, Hirata
Most promising method for observing the epoch of first stars is using the 21-cm spectral line of the neutral H atom. Discuss formation of the first stars in light of the effect of relative velocity between the DM and gas. Produce simulated maps of the first stars and show that the relative velocity effect significantly enhances LS clustering and produces a prominent cosmic web on 100 comoving Mpc scales in the 21cm intensity distribution. Should make it more feasible for radio astronomers to detect early stars from a cosmic age less than 200 million years [what's the redshift then?].
1201.1009
A direct measurement of hierarchical growth in galaxy groups since z~1
Williams, .. Dressler,.. et al
Measurement of the evolution of galaxy group stellar mass function (GrSMF) to z>1 and low masses (M*>1e12 Msun), based on Carnegie-Spitzer-IMACS (CSI) survey, 3.6 um selected sample of 37k galaxies over 5.3 deg sq to z~1.2. FoF finds ~4000 groups. Derived mass functions match up well with z>0.35 X-ray selected clusters, and strong evolution is evident at all masses over the past 8 Gyr. SF activity low at these masses, hence attribute observed growth in the GrSMF to group-group and group-galaxy mergers, in accordance with hierarchical structure formation. Factor 3-10 increase in the number density of groups and clusters with M*>1e12 Msun since z=1 and the strong anticorrelation between star formation activity and environmental density, this late-time growth in group-sized haloes may therefore be an important contributor ot the structural and SF evolution of massive galaxies over the past 8 Gyr.
1201.1010
CMB lensing and primordial squeezed non-Gaussianity
Pearson, Leewis, Regan
Squeezed primordial non-Gaussianity can strongly constrain early-universe physics, but it can only be observed on the CMB after it has been gravitationally lensed. ...
1201.1012
Survey design for SED fitting: a Fisher matrix approach
Acquaviva, Gawiser, Bickerton, Grogin, Guo, Lee
Fisher matrix formalism used to determine the best experimental setup to achieve the desired constraints on the SED fitting parameters from multi-wavelength observations, although since Fisher relies on Gaussian likelihood function, it is in general less accurate than other techniques that reconstruct the PDF from direct comparison between models and data. Compare Fisher vs PDF-based techniques using both simulated spectra and real data, and consider a large variety of target galaxies (z, mass, age, SFH, dust, wavelength coverage). Find uncertainties reported by the two methods agree within factor of 2 in most (90%) of the cases. Conclude: Fisher matrix is a useful tool for astronomical survey design.
1201.1013
The WiggleZ DES: Galaxy evolution at 0.25<z<0.75 using the second Red-Sequence cluster survey (RCS-2)
Li, Yee, Blake, ... Gladders, .. Hsieh, Glazebrook, .. et al
Red galaxy fraction low at high z. Optical color does not correlate to SF indicators such as OII WE or GALEX NUV luminosity.
1201.1019
Two-component galactic bulge probed with renewed galactic chemical evolution model
Tsujimoto, Bekki
Galactic bulge appears to have two stellar populations, represented by two peaks of stellar metallicity distribution (MDF) in the bulge. Include delay time distribution (DTD) of SNIa as well as nucleosynthesis clock in AGB stars in modelling: first shows that Mg, Fe, Ba for the bulge as well as the thin and thick disk is compatible with a short-delay SNIa. Successful modeling of two-component bulge, origins are: metal-poor component formed with relatively short timescale of ~1 Gyr, similar to the thick disk's characteristics in the solar vicinity. Metal-rich component formed with longer timescale (~4Gyr), from the remaining gas of the first component mixed with a gas flow from the disk outside the bulge, together with a top-heavy initial mass function that might be identified with the thin disk component within the bulge.
The Globular Cluster kinamatics and galaxy dark matter content of NGC 3923
Norris et al
Additional 50 GC and Ultra Compact Dwarf (UCD) candidates spectroscopically confirmed as members, along with 29 GCs. Sample extends to over 6 arcmin (> 6 Re ~ 30 kpc) from the center of NGC 3923, study dynamics of GC system and the DM content of NGC 3923: no rotation, velocity dispersion constant within the uncertainties. Axisymmetric orbit-based models to the GCs and integrated light velocity dispersion profiles demonstrates that a significant increase in the M/L ratio (from M/Lv of 8 to 26) at large galactocentric radii is required to explain these observations. Confirm presence of DM. DM comprises 17.5% of mass within 1Re, 41.2% within 2Re, and 75% within 6.9 Re. Total dynamical mass within this radius is found to be 1.5e12 Msun. Find that this dynamical mass profile is consistently higher than that derived by X-ray observations, by a factor of ~2 (consistent with other studies of large ellipticals).
1201.0999
Spectroscopy of broad line blazars from 1LAC
Shaw et al
The 165 Flat Spectrum Radio Quasars (FSRQs) in the Fermi 1LAC show evidence for non-thermal emission even in the optical, whose degree dpends on the gamma-ray hardness. Also have smaller virial estimates of the (BH) mass than the optical quasar sample, probably largely due to a preferred axial view of the gamma-ray FSRQ and non-isotropic (H/R~0.4) distribution of broad-line velocities. Fermi FSRQ show higher mean Eddington ratios than the optical populations, even after correcting for viewing angle bias. No strong correlation with optical spectral properties with radio flare activity.
1201.1000
Information escaping the correlation hierarchy of the convergence field in the study of cosmological parameters
Carron
From fits to numerical simulations, find that entire hierarchy of moments ceases to provide a complete description of the convergence one-point probability density function for values of the associated matter fluctuations variance as low as 0.1, still in the WL regime. At unit variance, only 5% of Fisher information content is still contained in hierarchy of moments. (Information escapes to higher order moments.) A simple logarithmic mapping makes the moments hierarchy well suited again for parameter extraction, putting 80% of the total information back into the first two and 95% in the first three members.
1201.1002
MOA-2011-BLG-293Lb: a testbed for pure survey microlensing planet detections
Yee, .. Gal-Yam, Bond, ...Gould, MOA collaboration, OGLE collaboration, MicroFUN collaboration
Test pure survey detections as a function of cadence (low cadence means less detection probability for planet microlensing).
1201.1003
Evidence for extended gamma-ray emission from galaxy clusters
Han, Frenk, Eke, Gao, White
3 year Fermi LAT data shows extended gamma-ray emission from the Virgo, Fornax and Coma clusters, within 3 degrees of the center, peaking at GeV scale; cannot be accounted for by known Fermi sources or by galactic and extragalactic BGs. If it's an annihilation emission of SUSY DM particles, then it's particles of mass 20-60 GeV annihilating into the b-bbar channel, or 2-10GeV and >1TeV annihilating into mu-mu final states. Results consistent with Fermi-LAT data from Galactic center. An extended DM annihilation profile dominated by emission from substructures is preferred over a simple point source model. If excess emission due to CR-induced gamma-rays, infer CR level within a factor of 3. The significance of CR component lower than DM component. Set upper limits on cross-section of b-bbar and mu-mu channels in the 3 clusters.
1201.1004
A new candidate for probing Pop II nucleosynthesis with carbon-enhanced damped Lyman-alpha systems
Cooke, Pettini, Murphy
Find a very metal-poor DLA (damped Lya system) at z=3.06 that is modestly C enhanced, with Fe abundance of 1/700 solar ([Fe/H] = -2.84, [C,O/Fe]~+0.6), likely to be result of nucleosynthesis of massive stars. From 17 metal absorption lines, derive 2 sigma upper limit on the DLA's kinetic temperature. Pop III, as well as high-mass Pop II stars match the abundance pattern well. Discuss limitation between distinguishing the two.
1201.1005
The grand cosmic web of the first stars
Visbal, Barkana, Fialkov, Tseliakhovich, Hirata
Most promising method for observing the epoch of first stars is using the 21-cm spectral line of the neutral H atom. Discuss formation of the first stars in light of the effect of relative velocity between the DM and gas. Produce simulated maps of the first stars and show that the relative velocity effect significantly enhances LS clustering and produces a prominent cosmic web on 100 comoving Mpc scales in the 21cm intensity distribution. Should make it more feasible for radio astronomers to detect early stars from a cosmic age less than 200 million years [what's the redshift then?].
1201.1009
A direct measurement of hierarchical growth in galaxy groups since z~1
Williams, .. Dressler,.. et al
Measurement of the evolution of galaxy group stellar mass function (GrSMF) to z>1 and low masses (M*>1e12 Msun), based on Carnegie-Spitzer-IMACS (CSI) survey, 3.6 um selected sample of 37k galaxies over 5.3 deg sq to z~1.2. FoF finds ~4000 groups. Derived mass functions match up well with z>0.35 X-ray selected clusters, and strong evolution is evident at all masses over the past 8 Gyr. SF activity low at these masses, hence attribute observed growth in the GrSMF to group-group and group-galaxy mergers, in accordance with hierarchical structure formation. Factor 3-10 increase in the number density of groups and clusters with M*>1e12 Msun since z=1 and the strong anticorrelation between star formation activity and environmental density, this late-time growth in group-sized haloes may therefore be an important contributor ot the structural and SF evolution of massive galaxies over the past 8 Gyr.
1201.1010
CMB lensing and primordial squeezed non-Gaussianity
Pearson, Leewis, Regan
Squeezed primordial non-Gaussianity can strongly constrain early-universe physics, but it can only be observed on the CMB after it has been gravitationally lensed. ...
1201.1012
Survey design for SED fitting: a Fisher matrix approach
Acquaviva, Gawiser, Bickerton, Grogin, Guo, Lee
Fisher matrix formalism used to determine the best experimental setup to achieve the desired constraints on the SED fitting parameters from multi-wavelength observations, although since Fisher relies on Gaussian likelihood function, it is in general less accurate than other techniques that reconstruct the PDF from direct comparison between models and data. Compare Fisher vs PDF-based techniques using both simulated spectra and real data, and consider a large variety of target galaxies (z, mass, age, SFH, dust, wavelength coverage). Find uncertainties reported by the two methods agree within factor of 2 in most (90%) of the cases. Conclude: Fisher matrix is a useful tool for astronomical survey design.
1201.1013
The WiggleZ DES: Galaxy evolution at 0.25<z<0.75 using the second Red-Sequence cluster survey (RCS-2)
Li, Yee, Blake, ... Gladders, .. Hsieh, Glazebrook, .. et al
Red galaxy fraction low at high z. Optical color does not correlate to SF indicators such as OII WE or GALEX NUV luminosity.
1201.1019
Two-component galactic bulge probed with renewed galactic chemical evolution model
Tsujimoto, Bekki
Galactic bulge appears to have two stellar populations, represented by two peaks of stellar metallicity distribution (MDF) in the bulge. Include delay time distribution (DTD) of SNIa as well as nucleosynthesis clock in AGB stars in modelling: first shows that Mg, Fe, Ba for the bulge as well as the thin and thick disk is compatible with a short-delay SNIa. Successful modeling of two-component bulge, origins are: metal-poor component formed with relatively short timescale of ~1 Gyr, similar to the thick disk's characteristics in the solar vicinity. Metal-rich component formed with longer timescale (~4Gyr), from the remaining gas of the first component mixed with a gas flow from the disk outside the bulge, together with a top-heavy initial mass function that might be identified with the thin disk component within the bulge.
1201.1058
The observational and theoretical tidal radii of globular clusters in M87
Webb, Sills, Harris
Globular clusters have linear sizes which are determined by their masses and by the gravitational potential of their host galaxy. Utilize globular cluster population of M87 (Virgo cluster giant elliptical). 2000 globular clusters measured with simulated clusters with similar characteristics of M87. Solve orbit of each cluster, compare prediction with observation. For isotropic distribution of cluster velocities, theoretical tidal radii approximately equal to observed limiting radii for Rgc<10kpc; but the steep increase in cluster size at larger radii is not observed in large galaxies beyond the MW.
1201.1079
A diversity of progenitors and histories for isolated spiral galaxies
Martig, Bournaud, Croton, Dekel, Teyssier
From 33 cosmo simulations following the evolution of MW-mass galaxies in low density environments, the sample at z=0 comprises galaxies with broad range of Hubble types. Bulges are typically pseudo-bulges with Sersic index lower than 2, and 70% of the galaxies have bars. A large fraction of the bulge is typically in place by z=1; find no significant correlation between the morphology at z=1 and z=0. Progenitors of disk galaxies span a while range of morphologies at z= 1, including smooth disks, unstable disks, interacting galaxies and bulge-dominated systems. By z=0.5, the morphology is correlated with the z=0 morphology, with spiral arms and bars largely in place at z=0.5. Analyze formation histories of galaxies with a bulge-to-total ratio below 0.3 (Sb and later): form in simulations at a lower abundance than observed, a common failure of cosmological simulations. Find correlation between the bulge fraction at z=0 and the mass ratio of the largest merger undergone after z=2, and a correlation with the gas accretion rate at z>1. Most disk dominated galaxies have an extremely quiet baryon input history, there are typically no major mergers after z=2, and gas is accreted at a low and constant rate, with the angular momentum stable at a fixed direction. More violent merger or gas accretion histories give birth to galaxies with more prominent bulges. Galaxies with the highest bulge Sersic index at z=0 are those with intense gas accretion and disk instabilities, including early bar formation, rather than the galaxies with the most active merger histories.
* they find: intense gas accretion leads to bulge formation, not active merger histories.
1201.1104
Heating and enriching the intracluster medium
Short, Thomas, Young
Numerical simulations of galaxy clusters with anisotropic heating from AGN that are able to reproduce the entropy and temperature profiles of both non-cool-core and cool-core clusters. How SF, metal enrichment, BH accretion and the associated feedback from SNe and AGN heat an enrich diffuse gas in galaxy clusters. Asses how different implementations of these processes affect the thermal and chemical properties of the ICM, using high-quality X-ray observations of local clusters to constrain the models. For the purposes of the study, resimulate a sample of 25 massive galaxy clusters extracted from Millennium Sim. Sub-grid physics in SAM. Find: SNe feedback has no effect on the entropy and metallicity structure of the ICM, regardless of the method used to inject energy and metals into the diffuse gas. AGN feedback is able to explain the observed entropy and metallicity profiles of clusters, as well as the X-ray luminosity-temperature scaling relation for NCC systems. A physical model of AGN energy injection based on anisotropic jet heating is crucial for this success. Addition of metal-dependent radiative cooling, the models is able to produce CC clusters, without over-cooling of gas in dense, central regions.
1201.1279
Studying SNe in the NUV with the NASA Swift UVOT Instrument
Milne, Brown
Optically normal SNIa feature NUV-optical color evolution that can be divided into NUV-blue and NUV-red groups, with roughly one-third of the observed events exhibiting NUV-blue color curves, which has a correlation with detection of unburned C in the optical spectra; hence this may be a fundamental difference within the normal SNIa classification.
1201.1282
Impact of systematics on SZ-Optical scaling realtions
Biesiadzinski, McMahon, Miller, Nord, Shaw
Systematic effects from optical cluster catalogs on stacked SZ signals: optically predicted Y decrement can vary by as much as 50%, based on the current 2 sigma systematic uncertainties in the observed mass-richness relationship. Mis-centering and impurities will suppress the SZ signal compared to expectations for a clean and perfectly centered optical sample, but to a lesser degree. Level of suppression and variation dependnet on the amount of systematics in the optical cluster catalogs. Luminosity-dependent sub-sampling of the optical catalog which creates malmquist-like effects that biases upwards the observed Y decrement of the stacked signal show that the current Planck measurements of the Y-decrement around SDSS optical clusters and their X-ray counterparts are consistent with expectations after accounting from the 1 sigma (2 sigma) optical systematic uncertainties using the Johnston (Rozo) mass-richness relation.
1201.0107
SSGSS: The Spitzer-SDSS-GALEX Spectroscopic survey
O'Dowd, Schiminovich, Johnston, Treyer, Martin, Wyder, Charlot, Heckman, Martins, Seibert, van der Hulst
SSGSS provides a new sample of 101 SF galaxies at z<0.2 with multi-wavelength coverage from FIR photometry from Spitzer, imaging and spectroscopy from SDSS, ROSAT, GALEX, 2MASS, Spitzer/SWIRE. Even coverage of full range of normal galaxy properties, spanning two orders of magnitude in stellar mass, color, and dust attenuation. Describe data, science drivers, sample selection, observation, reduction, quality assessment. Compare spectrum and silicate absorption of SF galaxies to starburst galaxies. Investigate link between SFR, IR luminosity and polycyclic aromatic hydrocarbon luminosity, with a vew to calibrating the latter for SED modesl in photometric samples and at high redshift. Take advantage of the 5-40 um spectro and FIR photometric coverage of this sample to perform detailed fitting of the dust models, investigate the link between dust mass and SFH and AGN properties.
1201.0128
Testing the minimum variance method for estimating large scale velocity moments
Agarwal, Feldman, Watkins
Test the robustness of the MV estimators (for large-scale bulk flow moments) using numerical simulations / mock catalogs. Show that MV estimators are negligibly affected by nonlinear flows; in particular they are unbiased and have errors that are consistent with predictions from linear theory.
1201.0151
Effect of massive neutrino on large scale structures
Dhungel, Sharma, Khanal
Hmm... Jeans mass calculation.
1201.0268
The interplay between CRs and magnetic turbulence in galaxy clusters: radio halos and gamma rays
Brunetti
Merging clusters can show giant radio halos, Mpc-scale synchrotron sources, which can probe connection between turbulence and non-thermal cluster-scale emission. After discussing relevant aspects of the physics of turbulence and turbulent acceleration in the ICM, describe recent advances in the modeling of non-thermal emission from galaxy clusters.
1201.0431
Dynamically evolving Mg II broad absorption line flow in SDSS J133356.02+001229.1
Vivek, Srianand, Mahabal, Kuriakose
Observations, part of ongoing monitoring of low ionization broad absorption line (BAL) QSOs with the 2m telescope at IUCAA. The broad Mg II absorption with ejection velocity of 1.7e4 km/s, found in SDSS spectra, has disappeared completely in their observation (!). Found an emerging new component at an ejection velocity of 2.8e4 km/s. This component has shown strong evolution during observation both in its velocity width and optical depth, and nearly disappeared in the latest observations. Observerd variations may not be related to inoization changes and are consistent with absorption produced by multi-streaming flow transiting across LoS. Find a possible connection between flux variation of the QSO and N(MgII) of the new component. Ejection being triggered by changes in the accretion disk or dust reddening due to the outflowing gas (could be).
1201.0546
Where stars form and live at high redshift: clues from the IR
Bethermin, Dore, Lagache
Abundance matching of IR galaxies to haloes: link between Mhalo and M*, SFR up to z~2. (1) strong evolution of the relation between M* and SFR as a function of z, with an increase of sSFR = SFR/M* by a factor ~20 between z=0 and 2.3. (2) observe a decrease of sSFR with stellar mass (match observed trends at z>0.3). (3) SF is most efficient in DM haloes with Mh~5e11 Msun, with hints of an increase of this mass with redshift. (4) SFR/Mh increases by a factor ~15 between z=0 and 2.3. (5) SFR density is dominated by halo masses close to 7e11 Msun at all redshift, with a rapid decrease at lower and higher halo masses.
* compared to Alexie's paper: at Msun~7e11 Msun at low 0.5<z<1.0, the stellar mass fraction f* is at maximum (~6%). At low z, the max f* is at a slightly lower halo mass (M500c)
* compared to Reina's paper: M* (stellar mass) ~ 2.7e10 Msun has the lowest M200/M* ratio (which should correspond to... Mhalo ~ 4e11 Msun, if f* is ~5%?)
1201.0570
Multi-scale probability mapping: groups, clusters and an algorithmic search for filaments in SDSS
Smith, Hopkins, Hunstead, Pimbblet
Multi-scale structure identification algorithm: combines density estimation with a shape statistic to identify local peaks in the density field. Identified catalogue of groups and clusters at 0.025<z<0.24 based on the SDSS DR7. most measured velocity dispersions for these structures lie between 50 and 400 km/s. A clear trend of increasing velocity dispersion with radius from 0.2 to 1 Mpc/h is detected, confirming the lack of a sharp division between groups and clusters. Method for quantifying elongation is also developed to measure the elongation of group and cluster environments. By using group and cluster catalogue as a coarse-grained representation of galaxy distributions for structure sizes of <1Mpc/h, identify 53 filaments (from 100 candidates) as elongated unions of groups and clusters at 0.025<z<0.13. These filaments have morphologies that are consistent with previous samples studied.
1201.0594
Bias, redshift space distortions and primordial nongaussianity of nonlinear transformations: application to Lyman alpha forest
Seljak
* hi boss!
On large scales, a NL transformation of matter density field can be viewed as a biased tracer of the density field itself. A NL transformation also modifies the z space distortions in the same limit, giving rise to a velocity bias. In models with primordial nongaussianity, a NL transformation generates a scale dependent bias on large scales. Derive analytic expressions for these for a general NL transformation. Analysis allows one to devise NL transformations with nearly arbitrary bias properties, which can be used to increase the signal in the LS clustering limit. Apply the results to the ionizing equilibrium model of Lya forest, in which Lya flux F is related to the density perturbation delta via a nonlinear transformation. Velocity bias can be expressed as an average over the Lya flux PDF. At z=2.4, predict the velocity bias of -0.1, compared to observed value of -0.13 pm 0.03. Bias and primordial nongaussianity bias depend on the parameters of the transformation. Measurements of bias can thus be used to constrain these parameters, and for reasonable values of the ionizing BG intensity, can match the predictions to observations. Matching to the observed values, predict the ratio of primordial nongaussianity bias to bias to have the opposite sign and lower magnitude than the corresponding values for the highly biased galaxies, but this depends on the model parameters and can also vanish or change the sign.
* Lya forest is anticorrelated to matter density contrast? it's negative.
The observational and theoretical tidal radii of globular clusters in M87
Webb, Sills, Harris
Globular clusters have linear sizes which are determined by their masses and by the gravitational potential of their host galaxy. Utilize globular cluster population of M87 (Virgo cluster giant elliptical). 2000 globular clusters measured with simulated clusters with similar characteristics of M87. Solve orbit of each cluster, compare prediction with observation. For isotropic distribution of cluster velocities, theoretical tidal radii approximately equal to observed limiting radii for Rgc<10kpc; but the steep increase in cluster size at larger radii is not observed in large galaxies beyond the MW.
1201.1079
A diversity of progenitors and histories for isolated spiral galaxies
Martig, Bournaud, Croton, Dekel, Teyssier
From 33 cosmo simulations following the evolution of MW-mass galaxies in low density environments, the sample at z=0 comprises galaxies with broad range of Hubble types. Bulges are typically pseudo-bulges with Sersic index lower than 2, and 70% of the galaxies have bars. A large fraction of the bulge is typically in place by z=1; find no significant correlation between the morphology at z=1 and z=0. Progenitors of disk galaxies span a while range of morphologies at z= 1, including smooth disks, unstable disks, interacting galaxies and bulge-dominated systems. By z=0.5, the morphology is correlated with the z=0 morphology, with spiral arms and bars largely in place at z=0.5. Analyze formation histories of galaxies with a bulge-to-total ratio below 0.3 (Sb and later): form in simulations at a lower abundance than observed, a common failure of cosmological simulations. Find correlation between the bulge fraction at z=0 and the mass ratio of the largest merger undergone after z=2, and a correlation with the gas accretion rate at z>1. Most disk dominated galaxies have an extremely quiet baryon input history, there are typically no major mergers after z=2, and gas is accreted at a low and constant rate, with the angular momentum stable at a fixed direction. More violent merger or gas accretion histories give birth to galaxies with more prominent bulges. Galaxies with the highest bulge Sersic index at z=0 are those with intense gas accretion and disk instabilities, including early bar formation, rather than the galaxies with the most active merger histories.
* they find: intense gas accretion leads to bulge formation, not active merger histories.
1201.1104
Heating and enriching the intracluster medium
Short, Thomas, Young
Numerical simulations of galaxy clusters with anisotropic heating from AGN that are able to reproduce the entropy and temperature profiles of both non-cool-core and cool-core clusters. How SF, metal enrichment, BH accretion and the associated feedback from SNe and AGN heat an enrich diffuse gas in galaxy clusters. Asses how different implementations of these processes affect the thermal and chemical properties of the ICM, using high-quality X-ray observations of local clusters to constrain the models. For the purposes of the study, resimulate a sample of 25 massive galaxy clusters extracted from Millennium Sim. Sub-grid physics in SAM. Find: SNe feedback has no effect on the entropy and metallicity structure of the ICM, regardless of the method used to inject energy and metals into the diffuse gas. AGN feedback is able to explain the observed entropy and metallicity profiles of clusters, as well as the X-ray luminosity-temperature scaling relation for NCC systems. A physical model of AGN energy injection based on anisotropic jet heating is crucial for this success. Addition of metal-dependent radiative cooling, the models is able to produce CC clusters, without over-cooling of gas in dense, central regions.
1201.1279
Studying SNe in the NUV with the NASA Swift UVOT Instrument
Milne, Brown
Optically normal SNIa feature NUV-optical color evolution that can be divided into NUV-blue and NUV-red groups, with roughly one-third of the observed events exhibiting NUV-blue color curves, which has a correlation with detection of unburned C in the optical spectra; hence this may be a fundamental difference within the normal SNIa classification.
1201.1282
Impact of systematics on SZ-Optical scaling realtions
Biesiadzinski, McMahon, Miller, Nord, Shaw
Systematic effects from optical cluster catalogs on stacked SZ signals: optically predicted Y decrement can vary by as much as 50%, based on the current 2 sigma systematic uncertainties in the observed mass-richness relationship. Mis-centering and impurities will suppress the SZ signal compared to expectations for a clean and perfectly centered optical sample, but to a lesser degree. Level of suppression and variation dependnet on the amount of systematics in the optical cluster catalogs. Luminosity-dependent sub-sampling of the optical catalog which creates malmquist-like effects that biases upwards the observed Y decrement of the stacked signal show that the current Planck measurements of the Y-decrement around SDSS optical clusters and their X-ray counterparts are consistent with expectations after accounting from the 1 sigma (2 sigma) optical systematic uncertainties using the Johnston (Rozo) mass-richness relation.
1201.0107
SSGSS: The Spitzer-SDSS-GALEX Spectroscopic survey
O'Dowd, Schiminovich, Johnston, Treyer, Martin, Wyder, Charlot, Heckman, Martins, Seibert, van der Hulst
SSGSS provides a new sample of 101 SF galaxies at z<0.2 with multi-wavelength coverage from FIR photometry from Spitzer, imaging and spectroscopy from SDSS, ROSAT, GALEX, 2MASS, Spitzer/SWIRE. Even coverage of full range of normal galaxy properties, spanning two orders of magnitude in stellar mass, color, and dust attenuation. Describe data, science drivers, sample selection, observation, reduction, quality assessment. Compare spectrum and silicate absorption of SF galaxies to starburst galaxies. Investigate link between SFR, IR luminosity and polycyclic aromatic hydrocarbon luminosity, with a vew to calibrating the latter for SED modesl in photometric samples and at high redshift. Take advantage of the 5-40 um spectro and FIR photometric coverage of this sample to perform detailed fitting of the dust models, investigate the link between dust mass and SFH and AGN properties.
1201.0128
Testing the minimum variance method for estimating large scale velocity moments
Agarwal, Feldman, Watkins
Test the robustness of the MV estimators (for large-scale bulk flow moments) using numerical simulations / mock catalogs. Show that MV estimators are negligibly affected by nonlinear flows; in particular they are unbiased and have errors that are consistent with predictions from linear theory.
1201.0151
Effect of massive neutrino on large scale structures
Dhungel, Sharma, Khanal
Hmm... Jeans mass calculation.
1201.0268
The interplay between CRs and magnetic turbulence in galaxy clusters: radio halos and gamma rays
Brunetti
Merging clusters can show giant radio halos, Mpc-scale synchrotron sources, which can probe connection between turbulence and non-thermal cluster-scale emission. After discussing relevant aspects of the physics of turbulence and turbulent acceleration in the ICM, describe recent advances in the modeling of non-thermal emission from galaxy clusters.
1201.0431
Dynamically evolving Mg II broad absorption line flow in SDSS J133356.02+001229.1
Vivek, Srianand, Mahabal, Kuriakose
Observations, part of ongoing monitoring of low ionization broad absorption line (BAL) QSOs with the 2m telescope at IUCAA. The broad Mg II absorption with ejection velocity of 1.7e4 km/s, found in SDSS spectra, has disappeared completely in their observation (!). Found an emerging new component at an ejection velocity of 2.8e4 km/s. This component has shown strong evolution during observation both in its velocity width and optical depth, and nearly disappeared in the latest observations. Observerd variations may not be related to inoization changes and are consistent with absorption produced by multi-streaming flow transiting across LoS. Find a possible connection between flux variation of the QSO and N(MgII) of the new component. Ejection being triggered by changes in the accretion disk or dust reddening due to the outflowing gas (could be).
1201.0546
Where stars form and live at high redshift: clues from the IR
Bethermin, Dore, Lagache
Abundance matching of IR galaxies to haloes: link between Mhalo and M*, SFR up to z~2. (1) strong evolution of the relation between M* and SFR as a function of z, with an increase of sSFR = SFR/M* by a factor ~20 between z=0 and 2.3. (2) observe a decrease of sSFR with stellar mass (match observed trends at z>0.3). (3) SF is most efficient in DM haloes with Mh~5e11 Msun, with hints of an increase of this mass with redshift. (4) SFR/Mh increases by a factor ~15 between z=0 and 2.3. (5) SFR density is dominated by halo masses close to 7e11 Msun at all redshift, with a rapid decrease at lower and higher halo masses.
* compared to Alexie's paper: at Msun~7e11 Msun at low 0.5<z<1.0, the stellar mass fraction f* is at maximum (~6%). At low z, the max f* is at a slightly lower halo mass (M500c)
* compared to Reina's paper: M* (stellar mass) ~ 2.7e10 Msun has the lowest M200/M* ratio (which should correspond to... Mhalo ~ 4e11 Msun, if f* is ~5%?)
1201.0570
Multi-scale probability mapping: groups, clusters and an algorithmic search for filaments in SDSS
Smith, Hopkins, Hunstead, Pimbblet
Multi-scale structure identification algorithm: combines density estimation with a shape statistic to identify local peaks in the density field. Identified catalogue of groups and clusters at 0.025<z<0.24 based on the SDSS DR7. most measured velocity dispersions for these structures lie between 50 and 400 km/s. A clear trend of increasing velocity dispersion with radius from 0.2 to 1 Mpc/h is detected, confirming the lack of a sharp division between groups and clusters. Method for quantifying elongation is also developed to measure the elongation of group and cluster environments. By using group and cluster catalogue as a coarse-grained representation of galaxy distributions for structure sizes of <1Mpc/h, identify 53 filaments (from 100 candidates) as elongated unions of groups and clusters at 0.025<z<0.13. These filaments have morphologies that are consistent with previous samples studied.
1201.0594
Bias, redshift space distortions and primordial nongaussianity of nonlinear transformations: application to Lyman alpha forest
Seljak
* hi boss!
On large scales, a NL transformation of matter density field can be viewed as a biased tracer of the density field itself. A NL transformation also modifies the z space distortions in the same limit, giving rise to a velocity bias. In models with primordial nongaussianity, a NL transformation generates a scale dependent bias on large scales. Derive analytic expressions for these for a general NL transformation. Analysis allows one to devise NL transformations with nearly arbitrary bias properties, which can be used to increase the signal in the LS clustering limit. Apply the results to the ionizing equilibrium model of Lya forest, in which Lya flux F is related to the density perturbation delta via a nonlinear transformation. Velocity bias can be expressed as an average over the Lya flux PDF. At z=2.4, predict the velocity bias of -0.1, compared to observed value of -0.13 pm 0.03. Bias and primordial nongaussianity bias depend on the parameters of the transformation. Measurements of bias can thus be used to constrain these parameters, and for reasonable values of the ionizing BG intensity, can match the predictions to observations. Matching to the observed values, predict the ratio of primordial nongaussianity bias to bias to have the opposite sign and lower magnitude than the corresponding values for the highly biased galaxies, but this depends on the model parameters and can also vanish or change the sign.
* Lya forest is anticorrelated to matter density contrast? it's negative.
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