bluuebunny/crossref_metadata_2025 huggingface dataset:
1-Butyl-3-Methylimidazolium Tetrafluoroborate Film as a Highly Selective Sensing Material for Non-Invasive Detection of Acetone Using a Quartz Crystal Microbalance
Authors: Tao Wenyan , Lin Peng , Liu Sili , Xie Qingji , Ke Shanming , Zeng Xierong
Published: January 2017

Breath acetone serves as a biomarker for diabetes. This article reports 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), a type of room temperature ionic liquid (RTIL), as a selective sensing material for acetone. The RTIL sensing layer was coated on a quartz crystal microbalance (QCM) for detection. The sensing mechanism is based on a decrease in viscosity and density of the [bmim][BF4] film due to the solubilization of acetone leading to a positive frequency shift in the QCM. Acetone was detected with a linear range from 7.05 to 750 ppmv. Sensitivity and limit of detection were found to be 3.49 Hz/ppmv and 5.0 ppmv, respectively. The [bmim][BF4]-modified QCM sensor demonstrated anti-interference ability to commonly found volatile organic compounds in breath, e.g., isoprene, 1,2-pentadiene, d-limonene, and dl-limonene. This technology is useful for applications in non-invasive early diabetic diagnosis.
Potential of Vertical Hydroponic Agriculture in Mexico
Authors: De Anda José , Shear Harvey
Published: January 2017

In 2050, Mexico’s population will reach 150 million people, about 80% of whom will likely live in urban centers. This increase in population will necessitate increased food production in the country. The lands classified as drylands in Mexico occupy approximately 101.5 million hectares, or just over half the territory, limiting the potential for agricultural expansion. In addition to the problem of arid conditions in Mexico, there are conditions in other parts of the country related to low to very low water availability, resulting in pressure on the water resources in almost two-thirds of the country. Currently, agriculture uses 77% of the water withdrawn, primarily for food production. This sector contributes 12% of the total greenhouse gas emission (GHG) production in the country. Given the conditions of pressure on water and land resources in Mexico and the need to reduce the carbon footprint, vertical farming technology could offer the possibility for sustainable food production in the urban areas of the country in the coming years.
Above and beyond C5a Receptor Targeting by Staphylococcal Leucotoxins: Retrograde Transport of Panton–Valentine Leucocidin and γ-Hemolysin
Authors: Zimmermann-Meisse Gaëlle , Prévost Gilles , Jover Emmanuel
Published: January 2017

Various membrane receptors associated with the innate immune response have recently been identified as mediators of the cellular action of Staphylococcus aureus leucotoxins. Two of these, the Panton–Valentine leucotoxin LukS-PV/LukF-PV and the γ-hemolysin HlgC/HlgB, bind the C5a complement-derived peptide receptor. These leucotoxins utilize the receptor to induce intracellular Ca2+ release from internal stores, other than those activated by C5a. The two leucotoxins are internalized with the phosphorylated receptor, but it is unknown whether they divert retrograde transport of the receptor or follow another pathway. Immunolabeling and confocal microscopic techniques were used to analyze the presence of leucotoxins in endosomes, lysosomes, endoplasmic reticulum, and Golgi. The two leucotoxins apparently followed retrograde transport similar to that of the C5a peptide-activated receptor. However, HlgC/HlgB reached the Golgi network very early, whereas LukS-PV/LukF-PV followed slower kinetics. The HlgC/HlgB leucotoxin remained in neutrophils 6 h after a 10-min incubation of the cells in the presence of the toxin with no signs of apoptosis, whereas apoptosis was observed 3 h after neutrophils were incubated with LukS-PV/LukF-PV. Such retrograde transport of leucotoxins provides a novel understanding of the cellular effects initiated by sublytic concentrations of these toxins.
Human Dental Pulp Stem Cells are more Effective than Human Bone Marrow-Derived Mesenchymal Stem Cells in Cerebral Ischemic Injury
Authors: Song Miyeoun , Lee Jae-Hyung , Bae Jinhyun , Bu Youngmin , Kim Eun-Cheol
Published: January 2017

We compared the therapeutic effects and mechanism of transplanted human dental pulp stem cells (hDPSCs) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in a rat stroke model and an in vitro model of ischemia. Rats were intravenously injected with hDPSCs or hBM-MSCs 24 h after middle cerebral artery occlusion (MCAo), and both groups showed improved functional recovery and reduced infarct volume versus control rats, but the hDPSC group showed greater reduction in infarct volume than the hBM-MSC group. The positive area for the endothelial cell marker was greater in the lesion boundary areas in the hDPSC group than in the hBM-MSC group. Administration of hDPSCs to rats with stroke significantly decreased reactive gliosis, as evidenced by the attenuation of MCAo-induced GFAP+/nestin+and GFAP+/Musashi-1+cells, compared with hBM-MSCs. In vivo findings were confirmed by in vitro data illustrating that hDPSCs showed superior neuroprotective, migratory, and in vitro angiogenic effects in oxygen–glucose deprivation (OGD)-injured human astrocytes (hAs) versus hBM-MSCs. Comprehensive comparative bioinformatics analyses from hDPSC- and hBM-MSC-treated in vitro OGD-injured hAs were examined by RNA sequencing technology. In gene ontology and KEGG pathway analyses, significant pathways in the hDPSC-treated group were the MAPK and TGF-β signaling pathways. Thus, hDPSCs may be a better cell therapy source for ischemic stroke than hBM-MSCs.
Anchored phylogenomics improves the resolution of evolutionary relationships in the rapid radiation ofProteaL.
Authors: Mitchell Nora , Lewis Paul O. , Lemmon Emily Moriarty , Lemmon Alan R. , Holsinger Kent E.
Published: January 2017

PREMISE OF THE STUDY:

Estimating phylogenetic relationships in relatively recent evolutionary radiations is challenging, especially if short branches associated with recent divergence result in multiple gene tree histories. We combine anchored enrichment next‐generation sequencing with species tree analyses to produce a robust estimate of phylogenetic relationships in the genusProtea(Proteaceae), an iconic radiation in South Africa.

METHODS:

We sampled multiple individuals within 59 out of 112 species ofProteaand 6 outgroup species for a total of 163 individuals, and obtained sequences for 498 low‐copy, orthologous nuclear loci using anchored phylogenomics. We compare several approaches for building species trees, and explore gene tree–species tree discrepancies to determine whether poor phylogenetic resolution reflects a lack of informative sites, incomplete lineage sorting, or hybridization.

KEY RESULTS:

Phylogenetic estimates from species tree approaches are similar to one another and recover previously well‐supported clades withinProtea, in addition to providing well‐supported phylogenetic hypotheses for previously poorly resolved intrageneric relationships. Individual gene trees are markedly different from one another and from species trees. Nonetheless, analyses indicate that differences among gene trees occur primarily concerning clades supported by short branches.

CONCLUSIONS:

Species tree methods using hundreds of nuclear loci provided strong support for many previously unresolved relationships in the radiation of the genusProtea. In cases where support for particular relationships remains low, these appear to arise from few informative sites and lack of information rather than strongly supported disagreement among gene trees.
Floral function: effects of traits on pollinators, male and female pollination success, and female fitness across three species of milkweeds (Asclepias)
Authors: La Rosa Raffica J. , Conner Jeffrey K.
Published: January 2017

PREMISE OF THE STUDY:

Central questions in plant reproductive ecology are whether the functions of floral traits in hermaphrodites create conflict between sexes that could slow evolution, and whether individual floral traits function in pollinator attraction, efficiency, or both. We studied how floral traits affect pollinator visitation and efficiency, and how they affect male and female function and female fitness within and across three Asclepias species that differ in floral morphology.

METHODS:

Using separate multiple regressions, we regressed pollen removal, deposition, and fruit number onto six floral traits. We also used path analyses integrating these variables with pollinator visitation data for two of the species to further explore floral function and its effects on fruit production.

KEY RESULTS:

Most traits affected male pollination success only, and these effects often differed between species. The exception was increased slit length, which increased pollinia insertion in two of the species. There were no interspecific differences in the effects of the traits on female pollination success. All traits except horn reach affected pollination efficiency in at least one species, and horn reach and two hood dimensions were the only traits to affect pollinator attraction, but in just one species.

CONCLUSIONS:

Traits tended to function in only one sex, and more traits affected function through pollinator efficiency than through attraction. There was no significant link between female pollination success and female fitness in any of the three species; this pattern is consistent with fruit production not being limited by pollen deposition.
DIFFERENT ORIGINS OR DIFFERENT EVOLUTIONS? DECODING THE SPECTRAL DIVERSITY AMONG C-TYPE ASTEROIDS
Authors: Vernazza P. , Castillo-Rogez J. , Beck P. , Emery J. , Brunetto R. , Delbo M. , Marsset M. , Marchis F. , Groussin O. , Zanda B. , Lamy P. , Jorda L. , Mousis O. , Delsanti A. , Djouadi Z. , Dionnet Z. , Borondics F. , Carry B.
Published: January 2017

Anhydrous pyroxene-rich interplanetary dust particles (IDPs) have been proposed as surface analogs for about two-thirds of all C-complex asteroids. However, this suggestion appears to be inconsistent with the presence of hydrated silicates on the surfaces of some of these asteroids, including Ceres. Here, we report the presence of enstatite (pyroxene) on the surface of two C-type asteroids (Ceres and Eugenia) based on their spectral properties in the mid-infrared range. The presence of this component is particularly unexpected in the case of Ceres, because most thermal evolution models predict a surface consisting of hydrated compounds only. The most plausible scenario is that Ceres’ surface has been partially contaminated by exogenous enstatite-rich material, possibly coming from the Beagle asteroid family. This scenario questions a similar origin for Ceres and the remaining C-types, and it possibly supports recent results obtained by the Dawn mission (NASA) that Ceres may have formed in the very outer solar system. Concerning the smaller D ∼ 200 km C-types such as Eugenia, both their derived surface composition (enstatite and amorphous silicates) and low density (<1.5 g cm−3) suggest that these bodies accreted from the same building blocks, namely chondritic porous, pyroxene-rich IDPs and volatiles (mostly water ice), and that a significant volume fraction of these bodies has remained unaffected by hydrothermal activity likely implying a late accretion. In addition, their current heliocentric distance may best explain the presence or absence of water ice at their surfaces. Finally, we raise the possibility that CI chondrites, Tagish-Lake-like material, or hydrated IDPs may be representative samples of the cores of these bodies.
PREPARING FOR ADVANCED LIGO: A STAR–GALAXY SEPARATION CATALOG FOR THE PALOMAR TRANSIENT FACTORY
Authors: Miller A. A. , Kulkarni M. K. , Cao Y. , Laher R. R. , Masci F. J. , Surace J. A.
Published: January 2017

The search for fast optical transients, such as the expected electromagnetic counterparts to binary neutron star mergers, is riddled with false positives (FPs) ranging from asteroids to stellar flares. While moving objects are readily rejected via image pairs separated by ∼1 hr, stellar flares represent a challenging foreground, significantly outnumbering rapidly evolving explosions. Identifying stellar sources close to and fainter than the transient detection limit can eliminate these FPs. Here, we present a method to reliably identify stars in deep co-adds of Palomar Transient Factory (PTF) imaging. Our machine-learning methodology utilizes the random forest (RF) algorithm, which is trained using

sources with Sloan Digital Sky Survey (SDSS) spectra. When evaluated on an independent test set, the PTF RF model outperforms the SExtractor star classifier by ∼4%. For faint sources (

mag), which dominate the field population, the PTF RF model produces a ∼19% improvement over SExtractor. To avoid false negatives in the PTF transient-candidate stream, we adopt a conservative stellar classification threshold, corresponding to a galaxy misclassification rate of 0.005. Ultimately, ∼

objects are included in our PTF point-source catalog, of which only ∼106 are expected to be galaxies. We demonstrate that the PTF RF catalog reveals transients that otherwise would have been missed. To leverage its superior image quality, we additionally create an SDSS point-source catalog, which is also tuned to have a galaxy misclassification rate of 0.005. These catalogs have been incorporated into the PTF real-time pipelines to automatically reject stellar sources as non-extragalactic transients.
THE RADIAL VELOCITY EXPERIMENT (RAVE): FIFTH DATA RELEASE
Authors: Kunder Andrea , Kordopatis Georges , Steinmetz Matthias , Zwitter Tomaž , McMillan Paul J. , Casagrande Luca , Enke Harry , Wojno Jennifer , Valentini Marica , Chiappini Cristina , Matijevič Gal , Siviero Alessandro , de Laverny Patrick , Recio-Blanco Alejandra , Bijaoui Albert , Wyse Rosemary F. G. , Binney James , Grebel E. K. , Helmi Amina , Jofre Paula , Antoja Teresa , Gilmore Gerard , Siebert Arnaud , Famaey Benoit , Bienaymé Olivier , Gibson Brad K. , Freeman Kenneth C. , Navarro Julio F. , Munari Ulisse , Seabroke George , Anguiano Borja , Žerjal Maruša , Minchev Ivan , Reid Warren , Bland-Hawthorn Joss , Kos Janez , Sharma Sanjib , Watson Fred , Parker Quentin A. , Scholz Ralf-Dieter , Burton Donna , Cass Paul , Hartley Malcolm , Fiegert Kristin , Stupar Milorad , Ritter Andreas , Hawkins Keith , Gerhard Ortwin , Chaplin W. J. , Davies G. R. , Elsworth Y. P. , Lund M. N. , Miglio A. , Mosser B.
Published: January 2017

Data Release 5 (DR5) of the Radial Velocity Experiment (RAVE) is the fifth data release from a magnitude-limited (

) survey of stars randomly selected in the Southern Hemisphere. The RAVE medium-resolution spectra (

) covering the Ca-triplet region (8410–8795 Å) span the complete time frame from the start of RAVE observations in 2003 to their completion in 2013. Radial velocities from 520,781 spectra of 457,588 unique stars are presented, of which 255,922 stellar observations have parallaxes and proper motions from the Tycho-Gaia astrometric solution in Gaia DR1. For our main DR5 catalog, stellar parameters (effective temperature, surface gravity, and overall metallicity) are computed using the RAVE DR4 stellar pipeline, but calibrated using recent K2 Campaign 1 seismic gravities and Gaia benchmark stars, as well as results obtained from high-resolution studies. Also included are temperatures from the Infrared Flux Method, and we provide a catalog of red giant stars in the dereddened color

interval (0.50, 0.85) for which the gravities were calibrated based only on seismology. Further data products for subsamples of the RAVE stars include individual abundances for Mg, Al, Si, Ca, Ti, Fe, and Ni, and distances found using isochrones. Each RAVE spectrum is complemented by an error spectrum, which has been used to determine uncertainties on the parameters. The data can be accessed via the RAVE Web site or the VizieR database.
Multiepoch Spectropolarimetry of SN 2011fe
Authors: Milne Peter A. , Williams G. Grant , Porter Amber , Smith Paul S. , Smith Nathan , Leising Mark D. , Jannuzi Buell T. , Green E. M.
Published: January 2017

We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii
λ6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.
ARRIVAL TIME DIFFERENCES BETWEEN GRAVITATIONAL WAVES AND ELECTROMAGNETIC SIGNALS DUE TO GRAVITATIONAL LENSING
Authors: Takahashi Ryuichi
Published: January 2017

In this study we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive earlier than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately 105
M
⊙(f/Hz)−1, where f is the GW frequency. The arrival time difference can reach ∼0.1 s (f/Hz)−1 if the signals have passed by a lens of mass ∼8000 M
⊙(f/Hz)−1 with the impact parameter smaller than the Einstein radius; therefore, it is more prominent for lower GW frequencies. For example, when a distant supermassive black hole binary (SMBHB) in a galactic center is lensed by an intervening galaxy, the time lag becomes of the order of 10 days. Future pulsar timing arrays including the Square Kilometre Array and X-ray detectors may detect several time lags by measuring the orbital phase differences between the GW/EM signals in the SMBHBs. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Determination of arrival time differences would be extremely useful in multimessenger observations and tests of general relativity.
KINEMATIC STRUCTURE OF MOLECULAR GAS AROUND HIGH-MASS YSO, PAPILLON NEBULA, IN N159 EAST IN THE LARGE MAGELLANIC CLOUD: A NEW PERSPECTIVE WITH ALMA
Authors: Saigo Kazuya , Onishi Toshikazu , Nayak Omnarayani , Meixner Margaret , Tokuda Kazuki , Harada Ryohei , Morioka Yuuki , Sewiło Marta , Indebetouw Remy , Torii Kazufumi , Kawamura Akiko , Ohama Akio , Hattori Yusuke , Yamamoto Hiroaki , Tachihara Kengo , Minamidani Tetsuhiro , Inoue Tsuyoshi , Madden Suzanne , Galametz Maud , Lebouteiller Vianney , Chen C.-H. Rosie , Mizuno Norikazu , Fukui Yasuo
Published: January 2017

We present the ALMA Band 3 and Band 6 results of 12CO(2-1), 13CO(2-1), H30α recombination line, free–free emission around 98 GHz, and the dust thermal emission around 230 GHz toward the N159 East Giant Molecular Cloud (N159E) in the Large Magellanic Cloud (LMC). LMC is the nearest active high-mass star-forming face-on galaxy at a distance of 50 kpc and is the best target for studing high-mass star formation. ALMA observations show that N159E is the complex of filamentary clouds with the width and length of ∼1 pc and several parsecs. The total molecular mass is 0.92 × 105
M
⊙ from the 13CO(2-1) intensity. N159E harbors the well-known Papillon Nebula, a compact high-excitation H ii region. We found that a YSO associated with the Papillon Nebula has the mass of 35 M
⊙ and is located at the intersection of three filamentary clouds. It indicates that the formation of the high-mass YSO was induced by the collision of filamentary clouds. Fukui et al. reported a similar kinematic structure toward two YSOs in the N159 West region, which are the other YSOs that have the mass of ≳35 M
⊙. This suggests that the collision of filamentary clouds is a primary mechanism of high-mass star formation. We found a small molecular hole around the YSO in Papillon Nebula with a sub-parsec scale. It is filled by free–free and H30α emission. The temperature of the molecular gas around the hole reaches ∼80 K. It indicates that this YSO has just started the distruction of parental molecular cloud.
THE ROLE OF PEBBLE FRAGMENTATION IN PLANETESIMAL FORMATION. II. NUMERICAL SIMULATIONS
Authors: Jansson Karl Wahlberg , Johansen Anders , Syed Mohtashim Bukhari , Blum Jürgen
Published: January 2017

Some scenarios for planetesimal formation go through a phase of collapse of gravitationally bound clouds of millimeter- to centimeter-size pebbles. Such clouds can form, for example, through the streaming instability in protoplanetary disks. We model the collapse process with a statistical model to obtain the internal structure of planetesimals with solid radii between 10 and 1000 km. During the collapse, pebbles collide, and depending on their relative speeds, collisions have different outcomes. A mixture of particle sizes inside a planetesimal leads to better packing capabilities and higher densities. In this paper we apply results from new laboratory experiments of dust aggregate collisions (presented in a companion paper) to model collision outcomes. We find that the internal structure of a planetesimal is strongly dependent on both its mass and the applied fragmentation model. Low-mass planetesimals have no/few fragmenting pebble collisions in the collapse phase and end up as porous pebble piles. The number of fragmenting collisions increases with increasing cloud mass, resulting in wider particle size distributions and higher density. The collapse is nevertheless “cold” in the sense that collision speeds are damped by the high collision frequency. This ensures that a significant fraction of large pebbles survive the collapse in all but the most massive clouds. Our results are in broad agreement with the observed increase in density of Kuiper Belt objects with increasing size, as exemplified by the recent characterization of the highly porous comet 67P/Churyumov–Gerasimenko.
DUST IN CLUSTERS: SEPARATING THE CONTRIBUTION OF GALAXIES AND INTRACLUSTER MEDIA
Authors: Gutiérrez C. M. , López-Corredoira M.
Published: January 2017

We have analyzed a sample of 327 clusters of galaxies, spanning the range of 0.06–0.70 in redshift. Strong constraints on their mean intracluster emission of dust have been obtained using maps and catalogs from the Herschel MerMES project; within a radius of 5 arcmin centered in each cluster, the 95% C.L. limits obtained are 86.6, 48.2, and 30.9 mJy at the observed frequencies of 250, 350, and 500 μm. From these restrictions, and assuming physical parameters typical of interstellar media in the Milky Way, we have obtained tight upper limits on the visual extinction of background galaxies due to the intracluster media (ICM): A

V
(95% C.L.) ≲ 10−3 mag. Strong constraints are also obtained for the mass of such dust; for instance, using the data at 350 μm we establish a 95% upper limit of <109
M
⊙ within a circle with a radius of 5 arcmin centered in the clusters. This corresponds to a fraction of the total mass of the clusters of 9.5 × 10−6, and indicates a deficiency in the gas-to-dust ratio in the ICM by about three orders of magnitude in relation to the value found in the Milky Way. Computing the total infrared luminosity of the clusters in three ranges of redshift (0.05–0.24, 0.24–0.42, and 0.42–0.71) and two ranges of mass (<1014 and >1014
M
⊙), respectively, a strong evolution of luminosity in redshift (L ∼ z
1.5) for both ranges of masses is found. The results indicate a strong declining in star formation rate with time in the last ∼6 Gyr.
GEMINGA’S PUZZLING PULSAR WIND NEBULA
Authors: Posselt B. , Pavlov G. G. , Slane P. O. , Romani R. , Bucciantini N. , Bykov A. M. , Kargaltsev O. , Weisskopf M. C. , Ng C.-Y.
Published: January 2017

We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures—two

≈
0.2

d

250

pc long lateral tails and a segmented axial tail of

≈
0.05

d

250

pc length, where

d

250

=
d

/

(
250

pc
)

. The photon indices of the power-law spectra of the lateral tails,

Γ
≈
1

, are significantly harder than those of the pulsar (

Γ
≈
1.5

) and the axial tail (

Γ
≈
1.6

). There is no significant diffuse X-ray emission between the lateral tails—the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indications of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scenario, the lateral tails could represent an azimuthally asymmetric shell whose hard emission is caused by the Fermi acceleration mechanism of colliding winds. In another scenario, the lateral tails could be luminous, bent polar outflows, while the blobs in the axial tail could represent a crushed torus. In a resemblance to planetary magnetotails, the blobs of the axial tail might also represent short-lived plasmoids, which are formed by magnetic field reconnection in the relativistic plasma of the pulsar wind tail.
BURST AND OUTBURST CHARACTERISTICS OF MAGNETAR 4U 0142+61
Authors: Göğüş Ersin , Lin Lin , Roberts Oliver J. , Chakraborty Manoneeta , Kaneko Yuki , Gill Ramandeep , Granot Jonathan , Horst Alexander J. van der , Watts Anna L. , Baring Matthew , Kouveliotou Chryssa , Huppenkothen Daniela , Younes George
Published: January 2017

We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 bursts from its three burst-active episodes in 2011, 2012 and the latest one in 2015 observed with Swift/Burst Alert Telescope and Fermi/Gamma-ray Burst Monitor. Bursts from 4U 0142+61 morphologically resemble typical short bursts from other magnetars. However, 4U 0142+61 bursts are less energetic compared to the bulk of magnetar bursts. We uncovered an extended tail emission following a burst on 2015 February 28, with a thermal nature, cooling over a timescale of several minutes. During this tail emission, we also uncovered pulse peak phase aligned X-ray bursts, which could originate from the same underlying mechanism as that of the extended burst tail, or an associated and spatially coincident but different mechanism.
SCUSS u-BAND EMISSION AS A STAR-FORMATION-RATE INDICATOR
Authors: Zhou Zhimin , Zhou Xu , Wu Hong , Fan Xiao-Hui , Fan Zhou , Jiang Zhao-Ji , Jing Yi-Peng , Li Cheng , Lesser Michael , Jiang Lin-Hua , Ma Jun , Nie Jun-Dan , Shen Shi-Yin , Wang Jia-Li , Wu Zhen-Yu , Zhang Tian-Meng , Zou Hu
Published: January 2017

We present and analyze the possibility of using optical u-band luminosities to estimate star-formation rates (SFRs) of galaxies based on the data from the South Galactic Cap u band Sky Survey (SCUSS), which provides a deep u-band photometric survey covering about 5000 deg2 of the South Galactic Cap. Based on two samples of normal star-forming galaxies selected by the BPT diagram, we explore the correlations between u-band, Hα, and IR luminosities by combing SCUSS data with the Sloan Digital Sky Survey and Wide-field Infrared Survey Explorer (WISE). The attenuation-corrected u-band luminosities are tightly correlated with the Balmer decrement-corrected Hα luminosities with an rms scatter of ∼0.17 dex. The IR-corrected u luminosities are derived based on the correlations between the attenuation of u-band luminosities and WISE 12 (or 22) μm luminosities, and then calibrated with the Balmer-corrected Hα luminosities. The systematic residuals of these calibrations are tested against the physical properties over the ranges covered by our sample objects. We find that the best-fitting nonlinear relations are better than the linear ones and recommended to be applied in the measurement of SFRs. The systematic deviations mainly come from the pollution of old stellar population and the effect of dust extinction; therefore, a more detailed analysis is needed in future work.
Cosmic Ray Acceleration by a Versatile Family of Galactic Wind Termination Shocks
Authors: Bustard Chad , Zweibel Ellen G. , Brooks Elyssa
Published: January 2017

There are two distinct breaks in the cosmic ray (CR) spectrum: the so-called “knee” around 3 × 1015 eV and the so-called “ankle” around 1018 eV. Diffusive shock acceleration (DSA) at supernova remnant (SNR) shock fronts is thought to accelerate galactic CRs to energies below the knee, while an extragalactic origin is presumed for CRs with energies beyond the ankle. CRs with energies between 3 × 1015 and 1018 eV, which we dub the “shin,” have an unknown origin. It has been proposed that DSA at galactic wind termination shocks, rather than at SNR shocks, may accelerate CRs to these energies. This paper uses the galactic wind model of Bustard et al. to analyze whether galactic wind termination shocks may accelerate CRs to shin energies within a reasonable acceleration time and whether such CRs can subsequently diffuse back to the Galaxy. We argue for acceleration times on the order of 100 Myr rather than a few billion years, as assumed in some previous works, and we discuss prospects for magnetic field amplification at the shock front. Ultimately, we generously assume that the magnetic field is amplified to equipartition. This formalism allows us to obtain analytic formulae, applicable to any wind model, for CR acceleration. Even with generous assumptions, we find that very high wind velocities are required to set up the necessary conditions for acceleration beyond 1017 eV. We also estimate the luminosities of CRs accelerated by outflow termination shocks, including estimates for the Milky Way wind.
THE INTERPRETATION OF THE MULTI-WAVELENGTH AFTERGLOW EMISSION OF SHORT GRB 140903A
Authors: Zhang Shuai , Jin Zhi-Ping , Wang Yuan-Zhu , Wei Da-Ming
Published: January 2017

GRB 140903A, a short duration γ-ray burst (SGRB) detected by Swift, is characterized by its long-lasting radio emission among SGRBs. In addition to the

∼

10

6

s radio afterglow emission, the afterglow of GRB 140903A displays a plateau from 103 s to

7
×

10

3

s

in the X-rays. In this work, we attribute the X-ray plateau to the energy injection into the decelerating blast wave and then model the later radio/optical/X-ray afterglow emission within the standard fireball afterglow model. The afterglow emission has been well reproduced with reasonable physical parameters, including a jet half-opening angle of ∼0.05.
THE COMPLETE INFRARED VIEW OF ACTIVE GALACTIC NUCLEI FROM THE 70 MONTH SWIFT/BAT CATALOG
Authors: Ichikawa Kohei , Ricci Claudio , Ueda Yoshihiro , Matsuoka Kenta , Toba Yoshiki , Kawamuro Taiki , Trakhtenbrot Benny , Koss Michael J.
Published: January 2017

We systematically investigate the near- to far-infrared (FIR) photometric properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky ultra-hard X-ray (14–195 keV) survey. Out of 606 non-blazar AGNs in the Swift/BAT 70 month catalog at high galactic latitudes of

, we obtain IR photometric data of 604 objects by cross-matching the AGN positions with catalogs from the WISE, AKARI, IRAS, and Herschel infrared observatories. We find a good correlation between the ultra-hard X-ray and mid-IR luminosities over five orders of magnitude (

). Informed by previous measurements of the intrinsic spectral energy distribution of AGNs, we find FIR pure-AGN candidates whose FIR emission is thought to be AGN-dominated with low star-formation activity. We demonstrate that the dust covering factor decreases with the bolometric AGN luminosity, confirming the luminosity-dependent unified scheme. We also show that the completeness of the WISE color–color cut in selecting Swift/BAT AGNs increases strongly with 14–195 keV luminosity.
ROTATION PERIODS OF WIDE BINARIES IN THE KEPLER FIELD
Authors: Janes K. A.
Published: January 2017

In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function (ACF) of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component, in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period–color diagram. Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions, are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapidly than others at the same mass. Finally, using the ACF as a measure of the activity level, I found that while the F, G, and early K stars become less active as their periods increase, there is no correlation between period and activity for the mid K to early M stars.
ORIGINS OF SCATTER IN THE RELATIONSHIP BETWEEN HCN 1-0 AND DENSE GAS MASS IN THE GALACTIC CENTER
Authors: Mills Elisabeth A. C. , Battersby Cara
Published: January 2017

We investigate the correlation of HCN 1-0 with gas mass in the central 300 pc of the Galaxy. We find that on the ∼10 pc size scale of individual cloud cores, HCN 1-0 is well correlated with dense gas mass when plotted as a log–log relationship. There is ∼0.75 dex of scatter in this relationship from clouds like Sgr B2, which has an integrated HCN 1-0 intensity of a cloud less than half its mass, and others that have HCN 1-0 enhanced by a factor of 2–3 relative to clouds of comparable mass. We identify the two primary sources of scatter to be self-absorption and variations in HCN abundance. We also find that the extended HCN 1-0 emission is more intense per unit mass than in individual cloud cores. In fact the majority (80%) of HCN 1-0 emission comes from extended gas with column densities below 7 × 1022 cm−2, accounting for 68% of the total mass. We find variations in the brightness of HCN 1-0 would only yield a ∼10% error in the dense gas mass inferred from this line in the Galactic center. However, the observed order of magnitude HCN abundance variations, and the systematic nature of these variations, warn of potential biases in the use of HCN as dense gas mass tracer in more extreme environments such as an active galactic nucleus and shock-dominated regions. We also investigate other 3 mm tracers, finding that HNCO is better correlated with mass than HCN, and might be a better tracer of cloud mass in this environment.
THE K2 GALACTIC ARCHAEOLOGY PROGRAM DATA RELEASE I: ASTEROSEISMIC RESULTS FROM CAMPAIGN 1
Authors: Stello Dennis , Zinn Joel , Elsworth Yvonne , Garcia Rafael A. , Kallinger Thomas , Mathur Savita , Mosser Benoit , Sharma Sanjib , Chaplin William J. , Davies Guy , Huber Daniel , Jones Caitlin D. , Miglio Andrea , Aguirre Victor Silva
Published: January 2017

NASA's
K2
mission is observing tens of thousands of stars along the ecliptic, providing data suitable for large-scale asteroseismic analyses to inform galactic archaeology studies. Its first campaign covered a field near the north Galactic cap, a region never covered before by large asteroseismic-ensemble investigations, and was therefore of particular interest for exploring this part of our Galaxy. Here we report the asteroseismic analysis of all stars selected by the K2 Galactic Archaeology Program during the mission's “north Galactic cap” campaign 1. Our consolidated analysis uses six independent methods to measure the global seismic properties, in particular the large frequency separation and the frequency of maximum power. From the full target sample of 8630 stars we find about 1200 oscillating red giants, a number comparable with estimates from galactic synthesis modeling. Thus, as a valuable by-product we find roughly 7500 stars to be dwarfs, which provide a sample well suited for galactic exoplanet occurrence studies because they originate from our simple and easily reproducible selection function. In addition, to facilitate the full potential of the data set for galactic archaeology, we assess the detection completeness of our sample of oscillating red giants. We find that the sample is at least nearly complete for stars with

/μHz

and

μHz. There is a detection bias against helium core burning stars with

μHz, affecting the number of measurements of

and possibly also

. Although we can detect oscillations down to

, our campaign 1 sample lacks enough faint giants to assess the detection completeness for stars fainter than

.
EXPANDING THE CATALOG: CONSIDERING THE IMPORTANCE OF CARBON, MAGNESIUM, AND NEON IN THE EVOLUTION OF STARS AND HABITABLE ZONES
Authors: Truitt Amanda , Young Patrick A.
Published: January 2017

Building on previous work, we have expanded our catalog of evolutionary models for stars with variable composition; here we present models for stars of mass 0.5–1.2 M
⊙, at scaled metallicities of 0.1–1.5 Z
⊙, and specific C/Fe, Mg/Fe, and Ne/Fe values of 0.58–1.72 C/Fe⊙, 0.54–1.84 Mg/Fe⊙, and 0.5–2.0 Ne/Fe⊙, respectively. We include a spread in abundance values for carbon and magnesium based on observations of their variability in nearby stars; we choose an arbitrary spread in neon abundance values commensurate with the range seen in other low Z elements due to the difficult nature of obtaining precise measurements of neon abundances in stars. As indicated by the results of Truitt et al., it is essential that we understand how differences in individual elemental abundances, and not just the total scaled metallicity, can measurably impact a star’s evolutionary lifetime and other physical characteristics. In that work, we found that oxygen abundances significantly impacted the stellar evolution; carbon, magnesium, and neon are potentially important elements to individually consider due to their relatively high (but also variable) abundances in stars. We present 528 new stellar main-sequence models, and we calculate the time-dependent evolution of the associated habitable zone boundaries for each based on mass, temperature, and luminosity. We also reintroduce the 2 Gyr “Continuously Habitable Zone” (CHZ2) as a useful tool to help gauge the habitability potential for a given planetary system.
THE FMOS-COSMOS SURVEY OF STAR-FORMING GALAXIES AT z ∼ 1.6. IV. EXCITATION STATE AND CHEMICAL ENRICHMENT OF THE INTERSTELLAR MEDIUM
Authors: Kashino D. , Silverman J. D. , Sanders D. , Kartaltepe J. S. , Daddi E. , Renzini A. , Valentino F. , Rodighiero G. , Juneau S. , Kewley L. J. , Zahid H. J. , Arimoto N. , Nagao T. , Chu J. , Sugiyama N. , Civano F. , Ilbert O. , Kajisawa M. , Le Fèvre O. , Maier C. , Masters D. , Miyaji T. , Onodera M. , Puglisi A. , Taniguchi Y.
Published: January 2017

We investigate the physical conditions of ionized gas in high-z star-forming galaxies using diagnostic diagrams based on the rest-frame optical emission lines. The sample consists of 701 galaxies with an Hα detection at

, from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS survey, that represent the normal star-forming population over the stellar mass range

, with those at

being well sampled. We confirm an offset of the average location of star-forming galaxies in the Baldwin–Phillips–Terlevich (BPT) diagram (

versus

), primarily toward higher

, compared with local galaxies. Based on the [S ii] ratio, we measure an electron density (

), which is higher than that of local galaxies. Based on comparisons to theoretical models, we argue that changes in emission-line ratios, including the offset in the BPT diagram, are caused by a higher ionization parameter both at fixed stellar mass and at fixed metallicity, with additional contributions from a higher gas density and possibly a hardening of the ionizing radiation field. Ionization due to active galactic nuclei is ruled out as assessed with Chandra. As a consequence, we revisit the mass–metallicity relation using

and a new calibration including

as recently introduced by Dopita et al. Consistent with our previous results, the most massive galaxies (

) are fully enriched, while those at lower masses have metallicities lower than local galaxies. Finally, we demonstrate that the stellar masses, metallicities, and star formation rates of the FMOS sample are well fit with a physically motivated model for the chemical evolution of star-forming galaxies.
THE TOPOLOGY OF CANONICAL FLUX TUBES IN FLARED JET GEOMETRY
Authors: Lavine Eric Sander , You Setthivoine
Published: January 2017

Magnetized plasma jets are generally modeled as magnetic flux tubes filled with flowing plasma governed by magnetohydrodynamics (MHD). We outline here a more fundamental approach based on flux tubes of canonical vorticity, where canonical vorticity is defined as the circulation of the species’ canonical momentum. This approach extends the concept of magnetic flux tube evolution to include the effects of finite particle momentum and enables visualization of the topology of plasma jets in regimes beyond MHD. A flared, current-carrying magnetic flux tube in an ion-electron plasma with finite ion momentum is thus equivalent to either a pair of electron and ion flow flux tubes, a pair of electron and ion canonical momentum flux tubes, or a pair of electron and ion canonical vorticity flux tubes. We examine the morphology of all these flux tubes for increasing electrical currents, different radial current profiles, different electron Mach numbers, and a fixed, flared, axisymmetric magnetic geometry. Calculations of gauge-invariant relative canonical helicities track the evolution of magnetic, cross, and kinetic helicities in the system, and show that ion flow fields can unwind to compensate for an increasing magnetic twist. The results demonstrate that including a species’ finite momentum can result in a very long collimated canonical vorticity flux tube even if the magnetic flux tube is flared. With finite momentum, particle density gradients must be normal to canonical vorticities, not to magnetic fields, so observations of collimated astrophysical jets could be images of canonical vorticity flux tubes instead of magnetic flux tubes.
NLTE ANALYSIS OF HIGH-RESOLUTION H-BAND SPECTRA. II. NEUTRAL MAGNESIUM*
Authors: Zhang Junbo , Shi Jianrong , Pan Kaike , Prieto Carlos Allende , Liu Chao
Published: January 2017

Aiming at testing the validity of our magnesium atomic model and investigating the effects of non-local thermodynamical equilibrium (NLTE) on the formation of the H-band neutral magnesium lines, we derive the differential Mg abundances from selected transitions for 13 stars either adopting or relaxing the assumption of local thermodynamical equilibrium (LTE). Our analysis is based on high-resolution and high signal-to-noise ratio H-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and optical spectra from several instruments. The absolute differences between the Mg abundances derived from the two wavelength bands are always less than 0.1 dex in the NLTE analysis, while they are slightly larger for the LTE case. This suggests that our Mg atomic model is appropriate for investigating the NLTE formation of the H-band Mg lines. The NLTE corrections for the Mg i
H-band lines are sensitive to the surface gravity, becoming larger for smaller log g values, and strong lines are more susceptible to departures from LTE. For cool giants, NLTE corrections tend to be negative, and for the strong line at 15765 Å they reach −0.14 dex in our sample, and up to −0.22 dex for other APOGEE stars. Our results suggest that it is important to include NLTE corrections in determining Mg abundances from the H-band Mg i transitions, especially when strong lines are used.
CHANDRA REVEALS HEAVY OBSCURATION AND CIRCUMNUCLEAR STAR FORMATION IN SEYFERT 2 GALAXY NGC 4968
Authors: LaMassa Stephanie M. , Yaqoob Tahir , Levenson N. A. , Boorman Peter , Heckman Timothy M. , Gandhi Poshak , Rigby Jane R. , Urry C. Megan , Ptak Andrew F.
Published: January 2017

We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z = 0.00986) Seyfert 2 galaxy. We discover extended (∼1 kpc) X-ray emission in the soft band (0.5–2 keV) that is neither coincident with the narrow line region nor the extended radio emission. Based on spectral modeling, it is linked to on-going star formation (∼2.6–4 M
⊙ yr−1). The soft emission at circumnuclear scales (inner ∼400 pc) originates from hot gas, with kT ∼ 0.7 keV, while the most extended thermal emission is cooler (kT ∼ 0.3 keV). We refine previous measurements of the extreme Fe Kα equivalent width in this source (

), which suggests the central engine is completely embedded within Compton-thick levels of obscuration. Using physically motivated models fit to the Chandra spectrum, we derive a Compton-thick column density (N
H > 1.25 × 1024 cm−2) and an intrinsic hard (2–10 keV) X-ray luminosity of ∼3–8 × 1042 erg s−1 (depending on the presumed geometry of the obscurer), which is over two orders of magnitude larger than that observed. The large Fe Kα EW suggests a spherical covering geometry, which could be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other active galaxies that exhibit extreme Fe Kα EWs (i.e., >2 keV) in that they also contain on-going star formation. This work supports the idea that gas associated with nuclear star formation may increase the covering factor of the enshrouding gas and play a role in obscuring active galactic nuclei.
REMOVING BIASES IN RESOLVED STELLAR MASS MAPS OF GALAXY DISKS THROUGH SUCCESSIVE BAYESIAN MARGINALIZATION
Authors: Martínez-García Eric E. , González-Lópezlira Rosa A. , Magris C. Gladis , Bruzual A. Gustavo
Published: January 2017

Stellar masses of galaxies are frequently obtained by fitting stellar population synthesis models to galaxy photometry or spectra. The state of the art method resolves spatial structures within a galaxy to assess the total stellar mass content. In comparison to unresolved studies, resolved methods yield, on average, higher fractions of stellar mass for galaxies. In this work we improve the current method in order to mitigate a bias related to the resolved spatial distribution derived for the mass. The bias consists in an apparent filamentary mass distribution and a spatial coincidence between mass structures and dust lanes near spiral arms. The improved method is based on iterative Bayesian marginalization, through a new algorithm we have named Bayesian Successive Priors (BSP). We have applied BSP to M51 and to a pilot sample of 90 spiral galaxies from the Ohio State University Bright Spiral Galaxy Survey. By quantitatively comparing both methods, we find that the average fraction of stellar mass missed by unresolved studies is only half what previously thought. In contrast with the previous method, the output BSP mass maps bear a better resemblance to near-infrared images.