Miracle-dz/UniFAR-FTUs huggingface dataset:
Search for associations containing young stars (SACY) - V. Is multiplicity universal? Tight multiple systems

Context. Dynamically undisrupted, young populations of stars are crucial in studying the role of multiplicity in relation to star formation. Loose nearby associations provide us with a great sample of close (<150 pc) pre-main sequence (PMS) stars across the very important age range (≈5-70 Myr) to conduct such research. Aims. We characterize the short period multiplicity fraction of the search for associations containing young stars (SACY) sample, accounting for any identifiable bias in our techniques and present the role of multiplicity fractions of the SACY sample in the context of star formation. Methods. Using the cross-correlation technique we identified double-lined and triple-lined spectroscopic systems (SB2/SB3s), in addition to this we computed radial velocity (RV) values for our subsample of SACY targets using several epochs of fiber-fed extended range optical spectrograph (FEROS) and ultraviolet and visual echelle spectrograph (UVES) data. These values were used to revise the membership of each association that was then combined with archival data to determine significant RV variations across different data epochs characteristic of multiplicity; single-lined multiple systems (SB1). Results. We identified seven new multiple systems (SB1s: 5, SB2s: 2). We find no significant difference between the short period multiplicity fraction (Fm) of the SACY sample and that of close star-forming regions (≈1-2 Myr) and the field (Fm ≤10%). These are seen both as a function of age and as a function of primary mass, M1, in the ranges P [1:200 day] and M2 [0.08 M -M1], respectively. Conclusions. Our results are consistent with the picture of universal star formation, when compared to the field and close star-forming regions (SFRs). We comment on the implications of the relationship between increasing multiplicity fraction with the primary mass within the close companion range in relation to star formation.
CONSERVATIVE MOMENT EQUATIONS FOR NEUTRINO RADIATION TRAN SPORT WITH LIMITED RELATIVITY

We derive conservative, multidimensional, energy-dependent moment equations for neutrino transport in core-collapse supernovae and related astrophysical systems, with particular attention to the consistency of conservative four-momentum and lepton number transport equations. After taking angular moments of conservative formulations of the general relativistic Boltzmann eq uation, we specialize to a conformally flat spacetime, which also serves as the basis for four further limits. Two of these—the multidimensional special relativistic case, and a conformally flat formulation of the spherically s ymmetric general relativistic case—are given in appendices for the sake of comparison with extant literature. The third limit is a weak-field, ‘pseudo-Newtonian’ approach (Kim et al. 2009, 2012) in which the source of the gravitational potential include s the trace of the stress-energy tensor (rather than just the mass density), a nd all orders in fluid velocity v are retained. Our primary interest here is in the fourth limit: ‘O(v)’ moment equations for use in conjunction with Newtonian sel fgravitating hydrodynamics. We show that the concept of ‘O(v)’ transport requires care when dealing with both conservative four-momentum and conservative lepton number transport, and present two self-consistent options: ‘O(v)-plus’ transport, in which an O(v 2 ) energy equation combines with an O(v) momentum equation to give an O(v 2 ) number equation; and ‘O(v)-minus’ transport, in which an O(v) energy equation combines with an O(1) momentum equation to give anO(v) number equation. Subject headings:neutrinos — radiative transfer — supernovae: general
Galaxy structure from multiple tracers – I. A census of M87's globular cluster populations

We present a new photometric catalogue of the rich globular cluster (GC) system around M87, the brightest cluster galaxy in Virgo. Using archival Next Generation Virgo cluster Survey (NGVS) images in the ugriz bands, observed with CFHT/MegaPrime, we perform a careful subtraction of the galaxy's halo light in order to detect objects at small galactocentric radii as well as in the wider field, and find 17620 GC candidates over a radius range from 1.3 kpc to 445 kpc with g < 24 magnitudes. By inferring their colour, radial and magnitude distributions in a Bayesian way, we find that they are well described as a mixture of two GC populations and two distinct contaminant populations, but confirm earlier findings of radius-dependent colour gradients in both GC populations. This is consistent with a picture in which the more enriched GCs reside deeper in the galaxy's potential well, indicating a role for dissipative collapse in the formation of both the red and the blue GCs.
ACTIVE GALACTIC NUCLEUS PAIRS FROM THE SLOAN DIGITAL SKY SURVEY. I. THE FREQUENCY ON ∼5–100 kpc SCALES

Galaxy–galaxy mergers and close interactions have long been regarded as a viable mechanism for channeling gas toward the central supermassive black holes (SMBHs) of galaxies which are triggered as active galactic nuclei (AGNs). AGN pairs, in which the central SMBHs of a galaxy merger are both active, are expected to be common from such events. We conduct a systematic study of 1286 AGN pairs at with line-of-sight velocity offsets Δv < 600 km s−1 and projected separations rp < 100 h−170 kpc, selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS). This AGN pair sample was drawn from 138,070 AGNs optically identified based on diagnostic emission line ratios and/or line widths. The fraction of AGN pairs with 5 h−170 kpc ≲ rp < 100 h−170 kpc among all spectroscopically selected AGNs at 0.02 < z < 0.16 is 3.6% after correcting for SDSS spectroscopic incompleteness; ∼30% of these pairs show morphological tidal features in their SDSS images, and the fraction becomes ≳ 80% for pairs with the brightest nuclei. Our sample increases the number of known AGN pairs on these scales by more than an order of magnitude. We study their AGN and host-galaxy star formation properties in a companion paper.
3D-HST GRISM SPECTROSCOPY OF A GRAVITATIONALLY LENSED, LOW-METALLICITY STARBURST GALAXY AT z = 1.847

We present Hubble Space Telescope (HST) imaging and spectroscopy of the gravitational lens SL2SJ02176-0513, a cusp arc at z = 1.847. The UV continuum of the lensed galaxy is very blue, which is seemingly at odds with its redder optical colors. The 3D-HST WFC3/G141 near-infrared spectrum of the lens reveals the source of this discrepancy to be extremely strong [O iii] λ5007 and Hβ emission lines with rest-frame equivalent widths of 2000 ± 100 and 520 ± 40 Å, respectively. The source has a stellar mass ∼108 M☉, sSFR ∼ 100 Gyr−1, and detection of [O iii] λ4363 yields a metallicity of 12 + log (O/H) = 7.5 ± 0.2. We identify local blue compact dwarf analogs to SL2SJ02176-0513, which are among the most metal-poor galaxies in the Sloan Digital Sky Survey. The local analogs resemble the lensed galaxy in many ways, including UV/optical spectral energy distribution, spatial morphology, and emission line equivalent widths and ratios. Common to SL2SJ02176-0513 and its local counterparts is an upturn at mid-IR wavelengths likely arising from hot dust heated by starbursts. The emission lines of SL2SJ02176-0513 are spatially resolved owing to the combination of the lens and the high spatial resolution of HST. The lensed galaxy is composed of two clumps with combined size re ∼300 pc, and we resolve significant differences in UV color and emission line equivalent width between them. Though it has characteristics occasionally attributed to active galactic nuclei, we conclude that SL2SJ02176-0513 is a low-metallicity star-bursting dwarf galaxy. Such galaxies will be found in significant numbers in the full 3D-HST grism survey.
Anisotropic Zeeman shift in p-type GaAs quantum point contacts

Low-temperature electrical conductance spectroscopy measurements of quantum point contacts implemented in p-type GaAs/AlGaAs heterostructures are used to study the Zeeman splitting of 1D subbands for both in-plane and out-of-plane magnetic field orientations. The resulting in-plane g-factors agree qualitatively with those of previous experiments on quantum wires while the quantitative differences can be understood in terms of the enhanced quasi-1D confinement anisotropy. The influence of confinement potential on the anisotropy is discussed and an estimate for the out-of-plane g-factor is obtained which, in contrast to previous experiments, is close to the theoretical prediction.
SOAR ADAPTIVE OPTICS OBSERVATIONS OF THE GLOBULAR CLUSTER NGC 6496

We present high-quality BVRI photometric data in the field of globular cluster NGC 6496 obtained with the SOAR Telescope Adaptive Module (SAM). Our observations were collected as part of the ongoing SAM commissioning. The distance modulus and cluster color excess as found from the red clump are (m − M)V = 15.71 ± 0.02 mag and E(V − I) = 0.28 ± 0.02 mag. An age of 10.5 ± 0.5 Gyr is determined from the difference in magnitude between the red clump and the subgiant branch. These parameters are in excellent agreement with the values derived from isochrone fitting. From the color–magnitude diagram we find a metallicity of [Fe/H] = −0.65 dex and hence support a disk classification for NGC 6496. The complete BVRI data set for NGC 6469 is made available in the electronic edition of the Journal.
THE OH LINE CONTAMINATION OF 21 cm INTENSITY FLUCTUATION MEASUREMENTS FOR z = 1–4

The large-scale structure of the universe can be mapped with unresolved intensity fluctuations of the 21 cm line. The power spectrum of the intensity fluctuations has been proposed as a probe of the baryon acoustic oscillations at low to moderate redshifts with interferometric experiments now under consideration. We discuss the contamination to the low-redshift 21 cm intensity power spectrum generated by the 18 cm OH line since the intensity fluctuations of the OH line generated at a slightly higher redshift contribute to the intensity fluctuations observed in an experiment. We assume the OH megamaser luminosity is correlated with the star formation rate and use the simulation to estimate the OH signal and the spatial anisotropies. We also use a semi-analytic simulation to predict the 21 cm power spectrum. At z = 1–3, we find that the OH contamination could reach 0.1%–1% of the 21 cm rms fluctuations at the scale of the first peak of the baryon acoustic oscillation. When z > 3 the OH signal declines quickly, so that the contamination on the 21 cm becomes negligible at high redshifts.
Quasiparticle scattering and the protected nature of the topological states in a parent topological insulator Bi 2 Se 3

We report on angle resolved photoemission spectroscopic studies on a parent topological insulator (TI), Bi$_2$Se$_3$. The line width of the spectral function (inverse of the quasi-particle lifetime) of the topological metallic (TM) states shows an anomalous behavior. This behavior can be reasonably accounted for by assuming decay of the quasi-particles predominantly into bulk electronic states through electron-electron interaction and defect scattering. Studies on aged surfaces reveal that topological metallic states are very much unaffected by the potentials created by adsorbed atoms or molecules on the surface, indicating that topological states could be indeed protected against weak perturbations.
Searching for dust reddening in SDSS spectra with damped Lyman α systems

We searched for evidence of the reddening of background quasi-stellar object (QSO) spectra from the Sloan Digital Sky Survey (SDSS) due to dust in intervening damped Lyman α systems (DLAs). We utilize the two Data Releases DR5 and DR7 to arrive at sample sizes of 475 (DR5) and 676 (DR7) absorbers, based on two different published lists of SDSS DLAs. Both samples span roughly the redshift range of 2.2 < Z abs < 5.2, with a mean of z ~ 3.0, and the majority of the DLAs (75 per cent) below z = 3.3. We construct geometric mean spectra in the absorber rest frames ranging from 1240 to ~2800 A, and composite spectra of samples matching the 'DLA' QSOs in i-band magnitude and emission redshift z em , but without absorption lines. By comparing the slopes of these composite spectra with their matched counterparts, we find no sign of reddening in the ensemble of the absorbers from these samples. Owing to both the unprecedently large sizes of the DLA samples themselves and the non-DLA SDSS QSO sample, from which we can draw our matching spectra, we can place very tight limits for this non-detection ((E(B - V)) = -0.0013 ± 0.0025 (DR5) and (E(B - V)) = -0.0017 ± 0.0022 (DR7). Interestingly, when applying our technique to the samples of York et al., Vanden Berk et al. (intervening and intrinsic Mg II absorbers) and the smaller DLA subsample and pool of comparison QSOs of Vladilo et al., we do recover their results, i.e. detect the same amount of reddening as these authors do. Furthermore, we have tested whether subsamples of our large sample in categories involving the absorbers (H column densities, presence or absence of accompanying metal absorption, absorber redshift) or the background quasars (emission redshift, brightness) do reveal dust extinction, but found no trends. These results are at odds with both detections of dust reddening from previous studies and expectations from observations of high-redshift galaxies.
A quasar-galaxy mixing diagram: quasar spectral energy distribution shapes in the optical to near-infrared

We define a quasar-galaxy mixing diagram using the slopes of their spectral energy distributions (SEDs) from 1\mu m to 3000\AA\ and from 1\mu m to 3\mu m in the rest frame. The mixing diagram can easily distinguish among quasar-dominated, galaxy-dominated and reddening-dominated SED shapes. By studying the position of the 413 XMM selected Type 1 AGN in the wide-field "Cosmic Evolution Survey" (COSMOS) in the mixing diagram, we find that a combination of the Elvis et al. (1994, hereafter E94) quasar SED with various contributions from galaxy emission and some dust reddening is remarkably effective in describing the SED shape from 0.3-3\mu m for large ranges of redshift, luminosity, black hole mass and Eddington ratio of type 1 AGN. In particular, the location in the mixing diagram of the highest luminosity AGN is very close (within 1\sigma) to that of the E94 SED. The mixing diagram can also be used to estimate the host galaxy fraction and reddening in quasar. We also show examples of some outliers which might be AGN in different evolutionary stages compared to the majority of AGN in the quasar-host galaxy co-evolution cycle.
TEMPERATURE STRUCTURE AND METALLICITY IN H ii REGIONS

The metallicities implied by collisionally excited lines (CELs) of heavy elements in H ii regions are systematically lower than those implied by recombination lines (RLs) by factors of ∼2, introducing uncertainties of the same order in the metallicities inferred for the interstellar medium of any star-forming galaxy. Most explanations of this discrepancy are based on the different sensitivities of CELs and RLs to electron temperature, and invoke either some extra heating mechanism producing temperature fluctuations in the ionized region or the addition of cold gas in metal-rich inclusions or ionized by cosmic rays or X-rays. These explanations will change the temperature structure of the ionized gas from the one predicted by simple photoionization models, and depending on which one is correct, will imply different metallicities for the emitting gas. We select nine H ii regions with observed spectra of high quality and show that simple models with metallicities close to the ones implied by oxygen CELs reproduce easily their temperature structure, measured with Te([N ii])/Te([O iii]), and their oxygen CELs emission. We discuss the strong constraints that this agreement places on the possible explanations of the discrepancy and suggest that the simplest explanation, namely errors in the line recombination coefficients by factors ∼2, might be the correct one. In such case, CELs will provide the best estimates of metallicity.
SDSS DR7 superclusters - Morphology

Aims. We study the morphology of a set of superclusters drawn from the SDSS DR7. Methods. We calculate the luminosity density field to determine super clusters from a flux-limited sample of galaxies from SDSS DR7, and select superclusters with 300 and more galaxies for our study. We characterise the morphology of superclusters using the fourth Minkowski functional V3, the morphological signature (the curve in the shapefinder’ s K1-K2 plane) and the shape parameter (the ratio of the shapefinders K1/K2). We investigate the supercluster sample using multidimensional normal mixture modelling. We use Abell clusters to identify our superclusters with known superclusters and to study the large-scale distribution of superclusters. Results. The superclusters in our sample form three chains of superclusters; one of them is the Sloan Great Wall. Most superclusters have filament-like overall shapes. Superclusters can be div ided into two sets; more elongated superclusters are more luminous, richer, have larger diameters, and a more complex fine structure than less elongated superclusters. The fine structure of supercl usters can be divided into four main morphological types: spiders, multispiders, filaments, and multibranching filaments. We presen t the 2D and 3D distribution of galaxies and rich groups, the fourth Minkowski functional, and the morphological signature for all superclusters. Conclusions. Widely different morphologies of superclusters show that their evolution has been dissimilar. A study of a larger sample of superclusters from observations and simulations is needed to understand the morphological variety of superclusters and the possible connection between the morphology of superclusters and their large-scale environment.
Neutrino signals from dark matter decay

We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the dark matter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and dark matter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different dark matter decay channels.
FAR-INFRARED PROPERTIES OF LYMAN BREAK GALAXIES FROM COSMOLOGICAL SIMULATIONS

Utilizing state-of-the-art adaptive mesh refinement cosmological hydrodynamic simulations with ultra-high resolution (114 h−1 pc) and a large sample size (⩾3300 galaxies of stellar mass ⩾109 M☉), we show how the stellar light of Lyman break galaxies at z = 2 is distributed between optical/ultraviolet (UV) and far-infrared (FIR) bands. With a single scalar parameter for dust obscuration we can simultaneously reproduce the observed UV luminosity function for the entire range (3–100 M☉ yr−1) and extant FIR luminosity function at the bright end (⩾20 M☉ yr−1). We quantify that galaxies more massive or having higher star formation rate (SFR) tend to have larger amounts of dust obscuration mostly due to a trend in column density and in a minor part due to a mass (or SFR)–metallicity relation. It is predicted that the FIR luminosity function in the range SFR = 1–100 M☉ yr−1 is a power law with a slope of about −1.7. We further predict that there is a “galaxy desert” at SFRFIR < 0.02(SFRUV/10 M☉ yr−1)2.1 M☉ yr−1 in the SFRUV − SFRFIR plane. Detailed distributions of SFRFIR at a fixed SFRUV are presented. Upcoming observations by the Atacama Large Millimeter Array should test this model. If confirmed, it validates the predictions of the standard cold dark matter model and has important implications on the intrinsic SFR function of galaxies at high redshift.
NO X-RAYS FROM THE VERY NEARBY TYPE Ia SN 2014J: CONSTRAINTS ON ITS ENVIRONMENT

Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN 2014J (dL = 3.5 Mpc) reveal no X-ray emission down to a luminosity Lx < 7 × 1036 erg s−1 (0.3–10 keV) at δt ∼ 20 days after the explosion. We interpret this limit in the context of inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be (for wind velocity vw = 100 km s−1). Alternatively, the SN shock might be expanding into a uniform medium with density nCSM < 3 cm−3. These results rule out single-degenerate (SD) systems with steady mass loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be ⩽1%. The allowed progenitors are (1) white dwarf–white dwarf progenitors, (2) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t < 300 yr, and (3) stars where the mass loss ceases before the explosion.
Ultra faint dwarf galaxies: an arena for testing dark matter versus modified gravity

The scenario consistent with a wealth of observations for the missing mass problem is that of weakly interacting dark matter particles. However, arguments or proposals for a Newtonian or relativistic modified gravity scenario continue to be made. A distinguishing characteristic between the two scenarios is that dark matter particles can produce a gravitational effect, in principle, without the need of baryons while this is not the case for the modified gravity scenario where such an effect must be correlated with the amount of baryonic matter. We consider here ultra-faint dwarf (UFD) galaxies as a promising arena to test the two scenarios based on the above assertion. We compare the correlation of the luminosity with the velocity dispersion between samples of UFD and non-UFD galaxies, finding a significant loss of correlation for UFD galaxies. For example, we find for 28 non-UFD galaxies a strong correlation coefficient of −0.688 which drops to −0.077 for the 23 UFD galaxies. Incoming and future data will determine whether the observed stochasticity for UFD galaxies is physical or due to systematics in the data. Such a loss of correlation (if it is to persist) is possible and consistent with the dark matter scenario for UFD galaxies but would constitute a new challenge for the modified gravity scenario.
2D stellar population and gas kinematics of the inner kiloparsec of the post-starburst quasar SDSS J0330−0532

We have used optical Integral Field Spectroscopy in order to map the star formation history of the inner kiloparsec of the post-starburst quasar (PSQ) J0330−0532 and to map its gas and stellar kinematics as well as the gas excitation. PSQs are hypothesized to represent a stage in the evolution of galaxies in which the star formation has been recently quenched due to the feedback of the nuclear activity, as suggested by the presence of the post-starburst population at the nucleus. We have found that the old stellar population (age ≥2.5Gyr) dominates theflux at 5100A in the inner 0.26kpc, while both the post-starburst (100Myr ≤ age <2.5Gyr) and starburst (age <100Myr) components dominate the flux in a circumnuclear ring at ≈0.5kpc fromthenucleus.Withourspatiallyresolvedstudywehavenotfoundanypost-starburststellar populationintheinner0.26kpc. Ontheotherhand,wedoseethesignatureofAGNfeedbackin this region, which does not reach the circumnuclear ring where the post-starburst population is observed. We thus do not support the quenching scenario for the PSQ J0330−0532. In addition, we have concluded that the strong signature of the post-starburst population in larger aperture spectra (e.g. from Sloan Digital Sky Survey) is partially due to the combination of the young and old age components. Based on the MBH − σstar relationship and the stellar kinematics we have estimated a mass for the supermassive black hole of 1.48 ± 0.66 × 10 7 M� .