Universidad de Concepcion
Star clusters were historically considered simple stellar populations, with all stars sharing the same age and initial chemical composition. However, the presence of chemical anomalies in globular clusters (GCs), called multiple stellar populations (MPs), has challenged star formation theories in dense environments. Literature studies show that mass, metallicity, and age are likely controlling parameters for the manifestation of MPs. Identifying the limit between clusters with/without MPs in physical parameter space is crucial to reveal the driving mechanism behind their presence. In this study, we look for MP signals in Whiting 1, traditionally considered a young GC. Using the Magellan telescope, we obtained low-resolution spectra within λλ=38505500A˚\rm \lambda\lambda = 3850-5500 Å for eight giants of Whiting 1. We measured the C and N abundances from the CN and CH spectral indices. C and N abundances have variations comparable with their measurement errors (0.1\sim0.1 dex), suggesting that MPs are absent from Whiting 1. Combining these findings with literature studies, we propose a limit in the metallicity vs. cluster compactness index parameter space, which relatively clearly separates star clusters with/without MPs (GCs/open clusters). This limit is physically motivated. On a larger scale, the galactic environment determines cluster compactness and metallicity, leading to metal-rich, diffuse, old clusters formed ex situ. Our proposed limit also impacts our understanding of the formation of the Sagittarius dwarf galaxy: star clusters formed after the first starburst (age810\lesssim 8-10 Gyr). These clusters are simple stellar populations because the enriched galactic environment is no longer suitable for MP formation.
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Mapping the local and distant Universe is key to our understanding of it. For decades, the Sloan Digital Sky Survey (SDSS) has made a concerted effort to map millions of celestial objects to constrain the physical processes that govern our Universe. The most recent and fifth generation of SDSS (SDSS-V) is organized into three scientific ``mappers". Milky Way Mapper (MWM) that aims to chart the various components of the Milky Way and constrain its formation and assembly, Black Hole Mapper (BHM), which focuses on understanding supermassive black holes in distant galaxies across the Universe, and Local Volume Mapper (LVM), which uses integral field spectroscopy to map the ionized interstellar medium in the local group. This paper describes and outlines the scope and content for the nineteenth data release (DR19) of SDSS and the most substantial to date in SDSS-V. DR19 is the first to contain data from all three mappers. Additionally, we also describe nine value added catalogs (VACs) that enhance the science that can be conducted with the SDSS-V data. Finally, we discuss how to access SDSS DR19 and provide illustrative examples and tutorials.
Supermassive black hole binary systems (SMBHBs) are thought to emit the recently discovered nHz gravitational wave background; however, not a single individual nHz source has been confirmed to date. Long-term radio-monitoring at the Owens Valley Radio Observatory has revealed two potential SMBHB candidates: blazars PKS 2131-021 and PKS J0805-0111. These sources show periodic flux density variations across the electromagnetic spectrum, signaling the presence of a good clock. To explain the emission, we propose a generalizable jet model, where a mildly relativistic wind creates an outward-moving helical channel, along which the ultra-relativistic jet propagates. The observed flux variation from the jet is mostly due to aberration. The emission at lower frequency arises at larger radius and its variation is consequently delayed, as observed. Our model reproduces the main observable features of both sources and can be applied to other sources as they are discovered. We make predictions for radio polarization, direct imaging, and emission line variation, which can be tested with forthcoming observations. Our results motivate future numerical simulations of jetted SMBHB systems and have implications for the fueling, structure, and evolution of blazar jets.
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We describe updated scientific goals for the wide-field, millimeter-wave survey that will be produced by the Simons Observatory (SO). Significant upgrades to the 6-meter SO Large Aperture Telescope (LAT) are expected to be complete by 2028, and will include a doubled mapping speed with 30,000 new detectors and an automated data reduction pipeline. In addition, a new photovoltaic array will supply most of the observatory's power. The LAT survey will cover about 60% of the sky at a regular observing cadence, with five times the angular resolution and ten times the map depth of Planck. The science goals are to: (1) determine the physical conditions in the early universe and constrain the existence of new light particles; (2) measure the integrated distribution of mass, electron pressure, and electron momentum in the late-time universe, and, in combination with optical surveys, determine the neutrino mass and the effects of dark energy via tomographic measurements of the growth of structure at z < 3; (3) measure the distribution of electron density and pressure around galaxy groups and clusters, and calibrate the effects of energy input from galaxy formation on the surrounding environment; (4) produce a sample of more than 30,000 galaxy clusters, and more than 100,000 extragalactic millimeter sources, including regularly sampled AGN light-curves, to study these sources and their emission physics; (5) measure the polarized emission from magnetically aligned dust grains in our Galaxy, to study the properties of dust and the role of magnetic fields in star formation; (6) constrain asteroid regoliths, search for Trans-Neptunian Objects, and either detect or eliminate large portions of the phase space in the search for Planet 9; and (7) provide a powerful new window into the transient universe on time scales of minutes to years, concurrent with observations from Rubin of overlapping sky.
Spatially-resolved emission line kinematics are invaluable to investigating fundamental galaxy properties and have become increasingly accessible for galaxies at z0.5z\gtrsim0.5 through sensitive near-infrared imaging spectroscopy and millimeter interferometry. Kinematic modeling is at the core of the analysis and interpretation of such data sets, which at high-z present challenges due to lower signal-to-noise ratio (S/N) and resolution compared to data of local galaxies. We present and test the 3D fitting functionality of DysmalPy, examining how well it recovers intrinsic disk rotation velocity and velocity dispersion, using a large suite of axisymmetric models, covering a range of galaxy properties and observational parameters typical of z1z\sim1-33 star-forming galaxies. We also compare DysmalPy's recovery performance to that of two other commonly used codes, GalPak3D and 3DBarolo, which we use in turn to create additional sets of models to benchmark DysmalPy. Over the ranges of S/N, resolution, mass, and velocity dispersion explored, the rotation velocity is accurately recovered by all tools. The velocity dispersion is recovered well at high S/N, but the impact of methodology differences is more apparent. In particular, template differences for parametric tools and S/N sensitivity for the non-parametric tool can lead to differences up to a factor of 2. Our tests highlight and the importance of deep, high-resolution data and the need for careful consideration of: (1) the choice of priors (parametric approaches), (2) the masking (all approaches) and, more generally, evaluating the suitability of each approach to the specific data at hand. This paper accompanies the public release of DysmalPy.
We present results from uGMRT 685 MHz observations of 87 QSOs belonging to the Palomar Green (PG) quasar sample with z<0.5. Radio emission is detected in all sources except for 3 radio-quiet (RQ) sources, viz., PG 0043+039, PG 1121+422, and PG 1552+085. The radio-loud (RL) - RQ dichotomy persists at 685 MHz with only 1 source, PG 1216+069, changing its classification from RQ to RL. Approximately 1/3 of the detected RQ quasars display AGN-dominated radio emission while the rest may show additional contributions from stellar-related processes. Consistent with this, the RL and RQ quasars occupy distinct tracks on the `fundamental plane' of black hole activity. We find that RL quasars have \log_{10}(L_{685\,\mathrm{MHz}}/\mathrm{W\,Hz}^{-1}) > 25.5, while RQ quasars have {\log_{10}(L_{685\,\mathrm{MHz}}/\mathrm{W\,Hz}^{-1})} <23.5. Furthermore, the radio sizes display the RQ-RL divide as well with RQ sources typically having sizes 30\lesssim30 kpc, with only 16 (22\sim22%) RQ sources having sizes between 30 and 100 kpc where there is an overlap with RL quasar sizes. A strong correlation exists between 685 MHz radio luminosity and black hole mass which is tightened when accretion rate is considered, highlighting the important role played by the accretion rate and accretion disk structure in jet production. We found no difference in the minimum-energy magnetic field strengths of the radio cores of RL and RQ quasars; however, different assumptions of source volume and volume filling factors may apply. High-resolution X-ray observations and radio-X-ray flux comparisons are needed to independently test the `magnetic flux paradigm'.
Quantum teleportation of qudits is revisited. In particular, we analyze the case where the quantum channel corresponds to a non-maximally entangled state and show that the success of the protocol is directly related to the problem of distinguishing non-orthogonal quantum states. The teleportation channel can be seen as a coherent superposition of two channels, one of them being a maximally entangled state thus, leading to perfect teleportation and the other, corresponding to a non-maximally entangled state living in a subspace of the d-dimensional Hilbert space. The second channel leads to a teleported state with reduced fidelity. We calculate the average fidelity of the process and show its optimality.
Stellar feedback drives multiphase gas outflows from starburst galaxies, but the interpretation of dust emission in these winds remains uncertain. To investigate this, we analyze new JWST mid-infrared images tracing polycyclic aromatic hydrocarbon (PAH) emission at 7.7 and 11.3~μ\mum from the outflow of the prototypical starburst M82 out to 3.23.2 kpc. We find that PAH emission shows significant correlations with CO, Hα\alpha, and X-ray emission within the outflow, though the strengths and behaviors of these correlations vary with gas phase and distance from the starburst. PAH emission correlates strongly with cold molecular gas, with PAH--CO scaling relations in the wind nearly identical to those in galaxy disks despite the very different conditions. The Hα\alpha--PAH correlation indicates that Hα\alpha traces the surfaces of PAH-bearing clouds, consistent with arising from ionized layers produced by shocks. Meanwhile the PAH--X-ray correlation disappears once distance effects are controlled for past 2~kpc, suggesting that PAHs are decoupled from the hot gas and the global correlation merely reflects the large-scale structure of the outflow. The PAH-to-neutral gas ratio remains nearly flat to 2~kpc, with variations following changes in the radiation field. This implies that the product of PAH abundance and dust-to-gas ratio does not change significantly over the inner portion of the outflow. Together, these results demonstrate that PAHs robustly trace the cold phase of M82's wind, surviving well beyond the starburst and providing a powerful, high-resolution proxy for mapping the life cycle of entrained cold material in galactic outflows.
We study the stellar mass function (SMF) and the co-evolution with dark matter halos via abundance matching in the largest redshift range to date 0.250.25, we find increased abundances of massive (log\, M_{\star}/M_{\odot}>10.5) implying integrated star formation efficiencies (SFE) ϵMfb1Mhalo10.5\epsilon_{\star}\equiv M_{\star}\, f_{\rm b}^{-1} M_{\rm halo}^{-1} \gtrsim 0.5. We find a flattening of the SMF at the high-mass end that is better described by a double power law at z>5.5. At z5.5z \lesssim 5.5 it transitions to a Schechter law which coincides with the emergence of the first massive quiescent galaxies in the Universe. We trace the cosmic stellar mass density (SMD) and infer the star formation rate density (SFRD), which at z>7.5 agrees remarkably with recent \JWST{} UV luminosity function-derived estimates. However, at z3.5z \lesssim 3.5, we find significant tension (0.3\sim 0.3 dex) with the cosmic star formation (SF) history from instantaneous SF measures, the causes of which remain poorly understood. We infer the stellar-to-halo mass relation (SHMR) and the SFE from abundance matching out to z=12z=12, finding a non-monotonic evolution. The SFE has the characteristic strong dependence with mass in the range of 0.020.20.02 - 0.2, and mildly decreases at the low mass end out to z3.5z\sim3.5. At z3.5z\sim3.5 the SFE increases sharply from 0.1\sim 0.1 to approach high SFE of 0.810.8-1 by z10z\sim 10 for log(Mh/M)11.5(M_{\rm h}/M_{\odot})\approx11.5, albeit with large uncertainties. Finally, we use the SHMR to track the SFE and stellar mass growth throughout the halo history and find that they do not grow at the same rate -- from the earliest times up until z3.5z\sim3.5 the halo growth rate outpaces galaxy assembly, but at z>3.5 halo growth stagnates and accumulated gas reservoirs keep the SF going and galaxies outpace halos.
We construct a family of supersymmetric solutions in Type IIB supergravity of the form WAdS3×WS3×T4{\rm WAdS}_3\times {\rm WS}^3\times T^4, where WAdS3{\rm WAdS}_3 and WS3{\rm WS^3} denote a warped anti-de Sitter spacetime and a warped 3-sphere, respectively, while T4T^4 denotes an internal 4-torus. These backgrounds are constructed by uplifting corresponding solutions in the D=6D=6, N=(1,1)\mathcal{N}=(1,1) ungauged supergravity resulting from the compactification of Type IIB supergravity on a T4/Z2T^4/\mathbb{Z}_2-orientifold. More specifically, the supersymmetric solutions are WAdS3×WS3×T4{\rm WAdS}_3\times {\rm WS}^3\times T^4 with lightlike warped AdS3_3 and WAdS3×S3×T4{\rm WAdS}_3\times {\rm S}^3\times T^4 in which the warping of AdS3_3 is generic. Moreover, we also construct solutions in the form of a warped product LMζ,ω3×wS3×T4\mathrm{LM}^3_{\zeta,\omega}\times_{\rm w} \mathrm{S}^3\times T^4 of a 2-parameter deformation LMζ,ω3\mathrm{LM}^3_{\zeta,\omega} of AdS3{\rm AdS}_3 and a three-sphere. We discuss the relation of these backgrounds to known solutions.
Effective cloud and cloud shadow detection is a critical prerequisite for accurate retrieval of concentrations of atmospheric methane or other trace gases in hyperspectral remote sensing. This challenge is especially pertinent for MethaneSAT and for its airborne companion mission, MethaneAIR. In this study, we use machine learning methods to address the cloud and cloud shadow detection problem for sensors with these high spatial resolutions instruments. Cloud and cloud shadows in remote sensing data need to be effectively screened out as they bias methane retrievals in remote sensing imagery and impact the quantification of emissions. We deploy and evaluate conventional techniques including Iterative Logistic Regression (ILR) and Multilayer Perceptron (MLP), with advanced deep learning architectures, namely UNet and a Spectral Channel Attention Network (SCAN) method. Our results show that conventional methods struggle with spatial coherence and boundary definition, affecting the detection of clouds and cloud shadows. Deep learning models substantially improve detection quality: UNet performs best in preserving spatial structure, while SCAN excels at capturing fine boundary details. Notably, SCAN surpasses UNet on MethaneSAT data, underscoring the benefits of incorporating spectral attention for satellite specific features. This in depth assessment of various disparate machine learning techniques demonstrates the strengths and effectiveness of advanced deep learning architectures in providing robust, scalable solutions for clouds and cloud shadow screening towards enhancing methane emission quantification capacity of existing and next generation hyperspectral missions. Our data and code is publicly available at this https URL
We present the WiFeS Atlas of Galactic Globular cluster Spectra, a library of integrated spectra of Milky Way and Local Group globular clusters. We used the WiFeS integral field spectrograph on the Australian National University 2.3 m telescope to observe the central regions of 64 Milky Way globular clusters and 22 globular clusters hosted by the Milky Way's low mass satellite galaxies. The spectra have wider wavelength coverage (3300 Å to 9050 Å) and higher spectral resolution (R = 6800) than existing spectral libraries of Milky Way globular clusters. By including Large and Small Magellanic Cloud star clusters, we extend the coverage of parameter space of existing libraries towards young and intermediate ages. While testing stellar population synthesis models and analysis techniques is the main aim of this library, the observations may also further our understanding of the stellar populations of Local Group globular clusters and make possible the direct comparison of extragalactic globular cluster integrated light observations with well understood globular clusters in the Milky Way. The integrated spectra are publicly available via the project website.
Phosphorus enhanced (P-rich; [P/Fe] > 0.8) giants have been found among mildly metal-poor fiels stars, but in only one star in a globular cluster (GC), M4 (NGC 6121). Also, in a sample of bulge spheroid stars, some of them showed a moderate P-enhancement in the range +0.5 < [P/Fe] < +1.0. In this paper we derive the P abundance of moderately metal-poor ([Fe/H] ~-1) GC stars, aiming to check if the phenomenon could be related to the unusual multiple stellar populations found in most GCs. Here we present the detection of P-moderately enhanced stars among two out of seven bulge GCs (Tonantzintla 1, and NGC 6316_, with metallicities similar to those of the bulge field P-rich stars. Using H-band high-resolution (R~22,500) spectra from the APOGEE-2 survey, we present the first high-resolution abundance analysis of [P/Fe] from the PI 16482.932 A line in a sample of selected bulge GCs. We find that all P-rich stars tend to also be N-rich, that hints at the origin of P-rich stars as second-generation stars in GCs. However no other correlations of P and other elements are found, that are usually indicators of second-generation stars. Further studies with larger samples and comparisons with field stars will be needed before any firm conclusions are drawn.
We characterize the stellar and gas volume density, potential, and gravitational field profiles in the central \sim 0.5 pc of the Orion Nebula Cluster (ONC), the nearest embedded star cluster (or rather, proto-cluster) hosting massive star formation available for detailed observational scrutiny. We find that the stellar volume density is well characterized by a Plummer profile ρstars(r)=5755Mpc3(1+(r/a)2)5/2\rho_{stars}(r) = 5755\,{\rm M}_{\odot}\,{\rm pc}^{-3}\,(1+(r/a)^2)^{-5/2}, where a=0.36a = 0.36 pc. The gas density follows a cylindrical power law ρgas(R)=25.9Mpc3(R/pc)1.775\rho_{gas}(R) = 25.9\,{\rm M}_{\odot}\,{\rm pc}^{-3}\,(R/{\rm pc})^{-1.775}. The stellar density profile dominates over the gas density profile inside r1r\,\sim\,1 pc. The gravitational field is gas-dominated at all radii, but the contribution to the total field by the stars is nearly equal to that of the gas at rar\,\sim\,a. This fact alone demonstrates that the proto-cluster cannot be considered a gas-free system or a virialized system dominated by its own gravity. The stellar proto-cluster core is dynamically young, with an age of \sim 2-3 Myr, a 1D velocity dispersion of σobs=2.6\sigma_{\rm obs} = 2.6 km s1^{-1}, and a crossing time of \sim 0.55 Myr. This timescale is almost identical to the gas filament oscillation timescale estimated recently by Stutz & Gould (2016). This provides strong evidence that the proto-cluster structure is regulated by the gas filament. The proto-cluster structure may be set by tidal forces due to the oscillating filamentary gas potential. Such forces could naturally suppress low density stellar structures on scales a\gtrsim\,a. The analysis presented here leads to a new suggestion that clusters form by an analog of the "slingshot mechanism" previously proposed for stars.
We present a set of preliminary simulations of intermediate mass ratio inspirals (IMRIs) inside dark matter (DM) spikes accounting for post-Newtonian corrections the interaction between the two black holes up to the order 2.5 in c2c^2, as well as relativistic corrections to the dynamical friction (DF) force exerted by the DM distribution. We find that, incorporating relativity reduces of a factor 1/21/2 the inspiral time, for equivalent initial orbital parameters, with respect to the purely classical estimates. Vice versa, neglecting the DF of the spike systematically yields longer inspiral times.
The circumstellar envelopes (CSE) of Cepheids are still not well characterized despite their potential impact on distance determination via both the period-luminosity relation and the parallax-of-pulsation method. This paper aims to investigate Galactic Cepheids across the instability strip in the mid-infrared with MATISSE/VLTI in order to constrain the geometry and physical nature (gas and/or dust) of their CSEs. We secured observations of eight Galactic Cepheids from short up to long period of pulsation, with MATISSE/VLTI in LL, MM and NN-bands. The SED analysis in the mid-IR confirms the absence of dust spectral signature for all the star sample. For each star in LL, MM and NN-band we observe closure phases which are consistent with centro-symmetric geometry for the different targets. Finally, the visibilities in LL, MM and NN bands are in agreement with the expected star angular diameter, although the observations are compatible with the presence of compact CSEs within the uncertainties. We provide 2σ\,\sigma upper limits on the CSE flux contribution based on model residuals for several CSE radius, which yield to exclude models simultaneously large and bright (RCSE10RR_\mathrm{CSE}\approx10\,R_\star and fCSE10%f_\mathrm{CSE}\approx10\%) for all the stars of the sample. Last, the visibilities in the NN-band rule out CSE models with significant amount of different type of dust. The MATISSE observations of eight Cepheids with different pulsation period (from 7 up to 38\,day) and evolution stage, provide for the first time a comprehensive picture of Cepheids from mid-IR interferometry. We present additional evidences that circumstellar dust emission is negligible or absent around Cepheids for a wide range of stellar parameters in the instability strip. Further interferometric observations in the visible and the near-infrared will be necessary to disentangle the star and the CSE.
We present a high-resolution kinematic study of the massive main-sequence star-forming galaxy (SFG) SDSS J090122.37+181432.3 (J0901) at z=2.259, using 0.36 arcsec ALMA CO(3-2) and 0.1-0.5 arcsec SINFONI/VLT H-alpha observations. J0901 is a rare, strongly-lensed but otherwise normal massive (log(M_star/M_sun)~11) main sequence SFG, offering a unique opportunity to study a typical massive SFG under the microscope of lensing. Through forward dynamical modeling incorporating lensing deflection, we fit the CO and H-alpha kinematics in the image plane out to about one disk effective radius (R_e ~ 4 kpc) at a ~600pc delensed physical resolution along the kinematic major axis. Our results show high intrinsic dispersions of the cold molecular and warm ionized gas (sig0_mol ~ 40 km/s and sig0_ion ~ 66 km/s) that remain constant out to R_e; a moderately low dark matter fraction (f_DM(R_e) ~ 0.3-0.4) within R_e; and a centrally-peaked Toomre Q-parameter -- agreeing well with the previously established sig0 vs. z, f_DM vs. Sig_baryon, and Q's radial trends using large-sample non-lensed main sequence SFGs. Our data further reveal a high stellar mass concentration within ~1-2 kpc with little molecular gas, and a clumpy molecular gas ring-like structure at R ~ 2-4 kpc, in line with the inside-out quenching scenario. Our further analysis indicates that J0901 had assembled half of its stellar mass only ~400 Myrs before its observed cosmic time, and cold gas ring and dense central stellar component are consistent with signposts of a recent wet compaction event of a highly turbulent disk found in recent simulations.
We modeled the V-band light curve of beta Lyrae with two stellar components plus an optically thick accretion disc around the gainer assuming a semidetached configuration. We present the results of this calculation, giving physical parameters for the stars and the disc, along with general system dimensions. We discuss the evolutionary stage of the system finding the best match with one of the evolutionary models of Van Rensbergen et al. According to this model, the system is found at age 2.30E7 years, in the phase of rapid mass transfer, the second one in the life of this binary, in a Case-B mass-exchange stage with dM/dt = 1.58E-5 Msun/year. This result, along with the reported rate of orbital period change and observational evidence of mass loss, suggests that the mass transfer in beta Lyrae, is quasi-conservative. The best model indicates that beta Lyrae finished a relatively large mass loss episode 31400 years ago. The light curve model that best fit the observations has inclination angle i = 81 degree, M1 = 13.2 Msun, M2 = 3.0 Msun, R1 = 6.0 Rsun and R2 = 15.2 Rsun. The disc contributes 22% to the total V-band light curve at quadrature, has a radius of 28.3 Rsun and the outer edge thickness is 11.2 Rsun. The light curve model is significantly better with two bright regions in the disc rim with temperatures 10% and 20% higher than the disc outer edge temperature. We compare our results with earlier studies of this interacting binary.
There is growing evidence that high-mass star formation and hub-filament systems (HFS) are intricately linked. The gas kinematics along the filaments and the forming high-mass star(s) in the central hub are in excellent agreement with the new generation of global hierarchical high-mass star formation models. In this paper, we present an observational investigation of a typical HFS cloud, G310.142+0.758 (G310 hereafter) which reveals unambiguous evidence of mass inflow from the cloud scale via the filaments onto the forming protostar(s) at the hub conforming with the model predictions. Continuum and molecular line data from the ATOMS and MALT90 surveys are used that cover different spatial scales. Three filaments (with total mass 5.7±1.1×103 M5.7\pm1.1\times 10^3~M_{\odot}) are identified converging toward the central hub region where several signposts of high-mass star formation have been observed. The hub region contains a massive clump (1280±260 M1280\pm260~M_{\odot}) harbouring a central massive core. Additionally, five outflow lobes are associated with the central massive core implying a forming cluster. The observed large-scale, smooth and coherent velocity gradients from the cloud down to the core scale, and the signatures of infall motion seen in the central massive clump and core, clearly unveil a nearly-continuous, multi-scale mass accretion/transfer process at a similar mass infall rate of 103 M yr1\sim 10^{-3}~M_{\odot}~yr^{-1} over all scales, feeding the central forming high-mass protostar(s) in the G310 HFS cloud.
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