bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Spitzer Study of Pseudobulges in S0 Galaxies: Secular Evolution of Disks
Authors: Barway Sudhanshu , Vaghmare Kaustubh , Mathur Smita , Kembhavi Ajit 
Published: March 2017

AbstractA comparison of pseudobulges in S0 and spiral galaxies is presented using structural parameters derived from 2-d decomposition of mid-infrared images taken at 3.6 μm by Spitzer IRAC. The position of the bulges on the Kormendy diagram has been used as an initial classification criterion for determining the nature of the bulge. To make the classification more secure, the criterion proposed by Fisher and Drory (2008) has also been used, which involves using the n = 2 division line on Sérsic index. We find that among the 185 S0 galaxies, 27 are pseudobulge hosts while 160 are classical. Of these 25 pseudobulge hosts, only two belong to the bright luminosity class (MK < 22.66, AB system) while rest belong to the faint luminosity class (MK > 22.66, AB system). We find that among spiral galaxies, 77 % (24 of 31) of the bulges are classified as pseudobulges. As pointed out by various studies, the presence of such a large fraction poses problems to our current picture of galaxy formation. How ever, our primary result is that the disk scale length of pseudobulge hosting S0s is significantly smaller on average than that of their spiral counterparts. This can be explained as a lowered disk luminosity which in turn implies that S0s have evolved from spiral progenitors. We also argue that early type spirals are more likely to be the progenitors based on bulge and total luminosity arguments. We speculate that if late type spirals hosting pseudobulges have to evolve into S0s, an additional mechanism along with gas stripping of spirals is needed. We have also investigated the effect of environment on pseudobulges in the two samples, but no significant trends were found in the properties of the pseudobulges as a function of the various structural parameters. The study is made more difficult because of the low number statistics one deals with when the sample is sub-divided based on whether it is in a field or group/cluster environment. The study of pseudobulges based on environment, however, is an interesting one and is something that can be considered for the future by carefully selecting a sample with statistically meaningful number of objects from diverse environments.
Using rotation measure to search for magnetic fields around galaxies at z ~ 0.5
Authors: Williams Anna , Lundgren Britt , Mao Sui Ann , Wilcots Eric , Zweibel Ellen 
Published: March 2017

AbstractMagnetic fields are an important component in galaxies, and yet, we still do not know how these magnetic fields were originally seeded within galaxies, nor how they have grown to the strengths we observe today. One way we can unravel this complex problem is by measuring the growth of magnetic fields over cosmic time. We present the initial results of a rotation measure study to search for the presence of coherent magnetic fields around young disk-like galaxies at z ~ 0.5. The S-band receiver at the VLA allows us to simultaneously observe Stokes I, Q, U, and V from 2-4 GHz. With these broadband polarization observations we apply multiple methods for determining the rotation measure of each source, improving the fidelity of our results. Beyond magnetogenesis, the results of this study also have implications for the life-cycle of baryons within galaxies and the composition of galactic haloes.
Large scale profiles of galaxies at z=0-2 studied by stacking the HSC SSP survey data
Authors: Kubo Mariko , Ouchi Masami , Shibuya Takatoshi 
Published: March 2017

AbstractWe are carrying out the study of the evolution of radial surface brightness profiles of galaxies from z = 0 to 2 by stacking analysis using data corrected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). This will allow us to constrain the large scale average profiles of various galaxy populations at high redshift. From the stacking analysis of galaxies selected based on their photometric redshifts, we successfully detected the outer components of galaxies at z > 1 extending to at least ~80 kpc, which imply an early formation for the galaxy outskirts.
Falling outer rotation curves of star-forming galaxies at 0.7 < z < 2.6 probed with KMOS3D and SINS/zC-SINF
Authors: Lang Philipp , Schreiber Natascha M. Förster , Genzel Reinhard , Burkert Andreas , Lutz Dieter , Tacconi Linda , Wisnioski Emily , Wuyts Stijn ,   the KMOS team
Published: March 2017

AbstractWe exploit the deep Hα IFU kinematic data from the KMOS3D and SINS/zC-SINF surveys to explore the so far unconstrained outer rotation curves of star-forming disk galaxies at high redshift. Through stacking the signal of ~ 100 massive disks at 0.7 < z < 2.6, we construct a representative rotation curve reaching out to several effective radii. Our stacked rotation curve exhibits a turnover with a steep falloff in the outer regions, significantly strengthening the tantalizing evidence previously hinted at in a handful only of individual disks among the sample with the deepest data.This finding confirms the high baryon fractions found by comparing the stellar, gas and dynamical masses of high redshift galaxies independently of assumptions on the light-to-mass conversion and Initial stellar Mass Function (IMF). The rapid falloff of the stacked rotation curve is most naturally explained by the effects of pressure gradients, which are significant in the gas-rich, turbulent high-z disks and which would imply a possible pressure-driven truncation of the outer disk.
Outer Disk Star Formation in HI selected Galaxies
Authors: Meurer G. R. 
Published: March 2017

AbstractThe HI in galaxies often extends past their conventionally defined optical extent. I report results from our team which has been probing low intensity star formation in outer disks using imaging in Hα and ultraviolet. Using a sample of hundreds of HI selected galaxies, we confirm that outer disk HII regions and extended UV disks are common. Hence outer disks are not dormant but are dimly forming stars. Although the ultraviolet light in galaxies is more centrally concentrated than the HI, the UV/HI ratio (the Star Formation Efficiency) is nearly constant, with a slight dependency on surface brightness. This result is well accounted for in a model where disks maintain a constant stability parameter Q. This model also accounts for how the ISM and star formation are distributed in the bright parts of galaxies, and how HI appears to trace the distribution of dark matter in galaxy outskirts.
New Conversion Laws for CO Observations
Authors: Barnes Peter J. , Muller Erik , Hernandez Audra K. , Duarte-Cabral Ana , Schuller Frederic 
Published: March 2017

AbstractWe describe new conversion laws, from CO molecular line data to inferred mass column, based on observations of the three main CO isotopologues in several surveys of the Galactic Plane. The new conversion laws replace the use of the single “X-factor” in widespread use, with a more physically-based relationship between the CO line’s optical depth, excitation, and column density. It has the effect of increasing the inferred mass column, over the single X-factor, by typically a factor of 2–3. This means that the molecular mass of the Milky Way may have been substantially underestimated in previous studies, and suggests that scaling laws like the Kennicutt-Schmidt relations may also need to be recalibrated. Because of its statistical basis on a large fraction of our Galaxy’s ISM, this new law is also recommended for use in studies of other Milky-Way-analogue spiral galaxies.
Stellar Spirals in Triaxial Dark Matter Halos
Authors: Hu Shaoran , Sijacki Debora 
Published: March 2017

AbstractTwo-armed grand-design spirals may form if the shape of its dark matter halo changes abruptly enough. The feasibility of such a mechanism is tested in realistic simulations. The interplay of such externally-driven spirals and self-induced transient spirals is then studied. Subhaloes are also found to lead to transient grand-design spiral structures when they impact the disk.
A ‘Universal’ Density Profile for the Outer Stellar Halos of Galaxies
Authors: Remus Rhea-Silvia , Burkert Andreas , Dolag Klaus 
Published: March 2017

AbstractThe outer stellar halos of galaxies contain vital information about the formation history of galaxies, since the relaxation timescales in the outskirts are long enough to keep the memory, while the information about individual formation events in the central parts has long been lost due to mixing, star formation and relaxation. To unveil some of the information encoded in these faint outer halo regions, we study the stellar outskirts of galaxies selected from a fully hydrodynamical high-resolution cosmological simulation, called Magneticum. We find that the density profiles of the outer stellar halos of galaxies over a broad mass range can be well described by an Einasto profile. For a fixed total mass range, the free parameters of the Einasto fits are closely correlated. Galaxies which had more (dry) merger events tend to have lesser curved outer stellar halos, however, we find no indication that the amount of curvature is correlated with galaxy morphology. The Einasto-like shape of the outer stellar halo densities can also explain the observed differences between the Milky Way and Andromeda outer stellar halos.
3D-spectroscopy of SBS star-forming galaxies
Authors: Hakopian S. A. , Dodonov S. N. , Moiseev A. V. , Smirnova A. A. 
Published: March 2017

AbstractIn the base of our studies of star-forming processes are the data provided by panoramic spectroscopy of galaxies composing our SBS subsample. Observations with multi-pupil spectrographs are organized in a way to obtain the spectral range centered in permitted hydrogen Hα Balmer line, by capturing at least the forbidden doublets of nitrogen [NII]6548,6583 and sulfur [SII]6716,6731. The results obtained are the spatial distributions across the targets of emission intensities and derived properties from line parameters such as radial velocities, which give us the possibility to explore gas kinematics and physical characteristics of HII regions.
Spatially-resolved SFR in nearby disk galaxies using IFS data
Authors: Catalán-Torrecilla C. , de Paz A. Gil , Castillo-Morales A. , Méndez-Abreu J. , Pascual S. , Ruiz-Lara T. , de Lorenzo-Cáceres A. , Sánchez-Menguiano L. 
Published: March 2017

AbstractExploring the spatial distribution of the star formation rate (SFR) in nearby galaxies is essential to understand their evolution through cosmic time. With this aim in mind, we use a representative sample that contains a variety of morphological types, the CALIFA Integral Field Spectroscopy (IFS) sample. Previous to this work, we have verified that our extinction-corrected Hα measurements successfully reproduce the values derived from other SFR tracers such as Hαobs + IR or UVobs + IR (Catalán-Torrecilla et al. 2015).Now, we go one step further applying 2-dimensional photometric decompositions (Méndez-Abreu et al. (2008), Méndez-Abreu et al. (2014)) over these datacubes. This method allows us to obtain the amount of SFR in the central part (bulge or nuclear source), the bar and the disk, separately. First, we determine the light coming from each component as the ratio between the luminosity in every component (bulge, bar or disk) and the total luminosity of the galaxy. Then, for each galaxy we multiply the IFS datacubes by these previous factors to recover the luminosity in each component. Finally, we derive the spectrum associated to each galaxy component integrating the spatial information in the weighted datacube using an elliptical aperture covering the whole galaxy.2D photometric decomposition applied over 3D datacubes will give us a more detailed understanding of the role that disks play in more massive galaxies. Knowing if the disks in more massive SF galaxies have on average a lower or higher level of star formation activity and how these results are affected by the presence of nuclear bars are still open questions that we can now solve. We describe the behavior of these components in the SFR vs. stellar mass diagram. In particular, we highlight the role of the disks and their contribution to both the integrated SFR for the whole galaxy and the SFR in the disk at different stellar masses in the SFR vs. stellar mass diagram together with their relative position to the star forming Main Sequence.
The Neutral Hydrogen Cosmological Mass Density at z = 5
Authors: Crighton Neil H. M. , Murphy Michael T. , Prochaska J. Xavier , Worseck Gábor , Rafelski Marc , Becker George D. , Ellison Sara L. , Fumagalli Michele , Lopez Sebastian , Meiksin Avery , O’Meara John M. 
Published: March 2017

AbstractWe present the largest homogeneous survey of redshift > 4.4 damped Lyα systems (DLAs) using the spectra of 163 quasars that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, ΩHI. After correcting for systematic effects using a combination of mock and higher-resolution spectra, we find ΩHI= 0.98+0.20-0.18 × 10−3 at 〈z〉 = 4.9, assuming a 20% contribution from lower column density systems below the DLA threshold. By comparing to literature measurements at lower redshifts, we show that ΩHI can be described by the functional form ΩHI(z) ∝ (1 + z)0.4. This gradual decrease from z = 5 to 0 suggests that in the galaxies which dominate the cosmic star formation rate, Hi is a transitory gas phase fuelling star formation which must be continually replenished by more highly-ionized gas from the intergalactic medium, and from recycled galactic winds.
The Circumgalactic Medium of Andromeda
Authors: Lehner Nicolas ,   the Project AMIGA team
Published: March 2017

AbstractOur view of galaxies has been transformed in recent years with diffuse halo gas surrounding galaxies that contains at least as many metals and baryons as their disks. While single sight lines through galaxy halos seen in absorption have provided key new constraints, they provide only average properties. Our massive neighbor, the Andromeda (M31) galaxy, provides an unique way to study its circumgalactic medium whereby we can study it using not one or two, but ~36 sightlines thanks to its proximity. With our Large HST program — Project AMIGA (Absorption Maps In the Gas of Andromeda), our goals are to determine the spatial distribution of the halo properties of a L* galaxy using 36 background targets at different radii and azimuths. In this brief paper, I discuss briefly the scientific rationale of Project AMIGA and some early science results. In particular, for the first time we have demonstrated that M31 has a gaseous halo that extends to Rvir with as much as metal and baryonic masses than in its disk and has substantial change in its ionization properties with more highly ionized gas found at R ~ Rvir than cooler gas found near the disk.
Outflows in low-mass galaxies at z >1
Authors: Maseda Michael V. ,   the MUSE GTO consortium
Published: March 2017

AbstractStar formation histories of local dwarf galaxies, derived through resolved stellar populations, appear complex and varied. The general picture derived from hydrodynamical simulations is one of cold gas accretion and bursty star formation, followed by feedback from supernovae and winds that heat and eject the central gas reservoirs. This ejection halts star formation until the material cools and re-accretes, resulting in an episodic SFH, particularly at stellar masses below ~ 109 M⊙. Such feedback has often been cited as the driving force behind the observed slowly-rising rotation curves in local dwarfs, due to an under-density of dark matter compared to theoretical models, which is one of the primary challenges to LCDM cosmology. However, these events have not yet been directly observed at high-redshift. Recently, using HST imaging and grism spectroscopy, we have uncovered an abundant population of low-mass galaxies (M* < 109 M⊙) at z = 1 - 2 that are undergoing strong bursts of star formation, in agreement with the theoretical predictions. These Extreme Emission Line Galaxies, with high specific SFRs and shallow gravitational potential wells, are ideal places to test the theoretical prediction of strong feedback-driven outflows. Here we use deep MUSE spectroscopy to search these galaxies for signatures of outflowing material, namely kinematic offsets between absorption lines (in the restframe optical and UV), which trace cool gas, and the nebular emission lines, which define the systemic redshift of the galaxy. Although the EELGs are intrinsically very faint, stacked spectra reveal blueshifted velocity centroids for Fe II absorption, which is indicative of outflowing cold gas. This represents the first constraint on outflows in M* < 109 M⊙ galaxies at z = 1 - 2. These outflows should regulate the star formation histories of low-mass galaxies at early cosmic times and thus play a crucial role in galaxy growth and evolution.
Results from the EDGES Survey
Authors: van Zee Liese ,   the EDGES Team
Published: March 2017

AbstractResults are presented from a deep imaging survey with the Spitzer Space Telescope which was designed to identify and measure the faint stellar populations around nearby galaxies. The Extended Disk Galaxy Exploration Science (EDGES) Survey includes a sample of 92 nearby galaxies with a range of morphological types and environments. The observations include a field-of-view of at least 5 times the optical size and are deep enough to detect stellar mass surface densities of several hundredths of a solar mass per square parsec. The observations reveal extended stellar features, such as stellar disks and stellar streams, around many of the target galaxies, as expected from hierarchical galaxy formation scenarios.
The build-up of the outskirts of distant star-forming galaxies at z ~ 2
Authors: Tacchella Sandro , Carollo C. Marcella , Dekel Avishai , Schreiber Natascha Förster , Renzini Alvio ,   zC-SINF Team
Published: March 2017

AbstractIn order to constrain – and understand – the growth of galaxies, we present a sample of ~ 30 galaxies at z ~ 2 with resolved distribution of stellar mass, star-formation rate, and dust attenuation on scales of ~ 1 kpc. We find that low- and intermediate-mass galaxies grow self-similarly, doubling their stellar mass in the centers and outskirts with the same pace. More massive galaxies (~ 1011 M⊙) have a reduced star-formation activity in their center: they grow mostly in the outskirts (inside-out quenching / formation). Similar trends are find in cosmological zoom-in simulations, highlighting that high stellar mass densities are formed in a gas-rich compaction phase. This nuclear ‘starburst’ phase is followed by a suppressed star-formation activity in the center, resulting in growth of the outskirts. All in all, we put forward that we witness at z ~ 2 the dissipative formation of z = 0 M* early-type galaxies.
Faint extended structures near galaxies: preliminary results from the Wise Observatory
Authors: Brosch Noah , Mosenkov Aleksandr , Rich R. Michael 
Published: March 2017

AbstractWe present the first results from a survey of deep imaging of edge-on galaxies, with the goal of testing the growth-by-accretion of galaxies proposed by ΛCDM. The data were obtained with a new telescope at the Wise Observatory. Our images show previously unreported extensions of the disk, tidal distortions, and streams at the level of 27-28 mag arcsec−2.
Probing Galactic Outskirts with Dragonfly
Authors: Abraham Roberto , Merritt Allison , Zhang Jielai , van Dokkum Pieter , Conroy Charlie , Danieli Shany , Mowla Lamiya 
Published: March 2017

AbstractWe describe the challenges inherent to low surface brightness imaging and present some early results from the Dragonfly Nearby Galaxies survey. Wide field, ultra-low surface brightness imaging (μg > 31 mag arcsec−2) of the first eight galaxies in the survey reveals a rich variety in the distribution of stars in the outskirts of luminous nearby galaxies. The mean stellar halo mass fraction is 0.009 ± 0.005 with a peak-to-peak scatter of a factor of > 100. Some galaxies in the sample feature strongly structured halos resembling that of M31, but three of the eight galaxies have halos that are completely undetected in our data. We conclude that spiral galaxies as a class exhibit a rich variety in stellar halo properties, implying that their assembly histories have been highly non-uniform. While the outskirts of some galaxies are dominated by halos with the rich substructures predicted by numerical simulations, in other cases the outermost parts of galaxies are simply the extrapolated smooth starlight from enormous stellar disks that closely trace neutral gas morphology out to around 20 scale lengths.
The Norwegian National Council for Priority Setting in Health Care: decisions and justifications
Authors: Wester Gry , Bringedal Berit 
Published: March 2017

AbstractDifferent countries have adopted different strategies for tackling the challenge of allocating scarce health care resources fairly. Norway is one of the countries that has pioneered the effort to resolve priority setting by using a core set of priority-setting criteria. While the criteria themselves have been subject to extensive debate and numerous revisions, the question of how the criteria have been applied in practice has received less attention. In this paper, we examine how the criteria feature in the decisions and justifications of the Norwegian National Council for Priority Setting in Health Care, which has played an active role in deliberating about health care provision and coverage in Norway. We conducted a comprehensive document analysis, looking at the Council’s decisions about health care allocation as well as the reasons they had provided to justify their decisions. We found that although the Council often made use of the official priority-setting criteria, they did so in an unsystematic and inconsistent manner.
Zika virus evades interferon-mediated antiviral response through the co-operation of multiple nonstructural proteins in vitro
Authors: Wu Yaoxing , Liu Qingxiang , Zhou Jie , Xie Weihong , Chen Cheng , Wang Zefang , Yang Haitao , Cui Jun 
Published: March 2017

AbstractType I interferon (IFN) serves as the first line of defense against invading pathogens. Inhibition of IFN-triggered signaling cascade by Zika virus (ZIKV) plays a critical role for ZIKV to evade antiviral responses from host cells. Here we demonstrate that ZIKV nonstructural proteins NS1, NS4B and NS2B3 inhibit the induction of IFN and downstream IFN-stimulated genes through diverse strategies. NS1 and NS4B of ZIKV inhibit IFNβ signaling at TANK-binding kinase 1 level, whereas NS2B-NS3 of ZIKV impairs JAK–STAT signaling pathway by degrading Jak1 and reduces virus-induced apoptotic cell death. Furthermore, co-operation of NS1, NS4B and NS2B3 further enhances viral infection by blocking IFN-induced autophagic degradation of NS2B3. Hence, our study reveals a novel antagonistic system employing multiple ZIKV nonstructural proteins in restricting the innate antiviral responses.