Instituto de Astrofísica de La Plata (IALP)

AstroInspect: A Web-based System to Organize, Assess, and Visually Inspect Astronomical Objects

2026-06-19T20:25:16Z

Articulo The Astronomical Journal; vol. 171, no. 5 The rapid growth of imaging and spectroscopic surveys has intensified the need for efficient tools that support visual inspection, a practice that remains essential for tasks such as classification, catalog refinement, and validation of automated methods. Existing solutions, however, often require the use of multiple platforms and complex workflows to integrate heterogeneous data. To address this challenge, we present the first release of AstroInspect, a web-based system designed to ensure seamless access to several astronomical resources. The system provides an intuitive graphical user interface that allows users to upload catalogs of objects defined by celestial coordinates. AstroInspect automatically enriches these catalogs with complementary information, including imaging, spectroscopic, and photometric data retrieved in real time from surveys such as the Sloan Digital Sky Survey, the Legacy Surveys, and the Southern Photometric Local Universe Survey (S-PLUS). To demonstrate its scientific utility, we used AstroInspect to identify Hα emission-line galaxies within a 7 deg radius in the direction of the Hydra I cluster (also known as A1060) by visual inspection. Using a candidate set of 981 galaxies selected from S-PLUS photometric data, we produced a catalog of 80 galaxies with confirmed Hα emission. These results highlight the potential of AstroInspect to support efficient visual inspection workflows.

The Hidden Life of Stars: Embedded Beginnings to Asymptotic Giant Branch Endings in the PHANGS–JWST Sample. I. Catalog of Mid-infrared Sources

2026-06-19T20:25:17Z

Articulo The Astrophysical Journal Supplement Series; vol. 284, no. 1 We present a multiwavelength catalog of mid-infrared-selected compact sources in 19 nearby galaxies, combining JWST NIRCam/MIRI, Hubble Space Telescope UV–optical broadband, Hα narrowband, and Atacama Large Millimeter/submillimeter Array CO observations. We detect 24,945 compact sources at 21 μm and 55,581 at 10 μm. Artificial star tests show 50% completeness limits of ∼5 μJy for the 10 μm catalog, and ∼24 μJy for the 21 μm catalog. We find that 21 μm compact sources contribute ∼20% of the total galaxy emission in that band, but only contribute 5% at 10 μm. We classify sources using stellar evolution and population synthesis models combined with empirical classifications derived from the literature. Our classifications include Hα-bright and dust-embedded optically faint clusters, red supergiants, oxygen-rich and carbon-rich asymptotic giant branch stars, and a range of rarer stellar types. In sampling a broad range of star-forming environments with a uniform, well-characterized selection, this catalog enables analyses of infrared-bright stellar populations. We find that Hα- faint sources account for only 10% of dusty (likely young) clusters, implying that the infrared-bright, optically faint phase of cluster evolution is short compared to the Hα-bright stage. The luminosity functions of 10 and 21 μm sources follow power-law distributions, with the 21 μm slope (−1.7 ± 0.1) similar to that of giant molecular cloud mass functions and ultraviolet bright star-forming complexes, while the 10 μm slope (−2.0 ± 0.1) is closer to that of young stellar clusters. La lista completa de autores que integran el documento puede consultarse en el archivo.

Predicted incidence of Jupiter-like planets around white dwarfs

2026-06-12T20:27:46Z

Articulo Astronomy & Astrophysics; vol. 707 Context. Gas-giant planets and brown dwarfs have been discovered in large numbers around main-sequence stars and even evolved stars. In contrast, and despite ongoing imaging surveys using state-of-the-art facilities, only a handful of substellar companions to white dwarfs are known. It remains unclear whether this paucity reflects observational challenges or the consequences of stellar evolution. Aims. We aim to carry out population synthesis of substellar objects around white dwarfs to predict the fraction and properties of white dwarfs hosting substellar companions. Methods. We generated a representative population of white-dwarf progenitors (up to 4 M⊙ ) with substellar companions, adopting companion distributions derived from radial-velocity surveys of giant stars and a global age–metallicity relation. We then combined the stellar-evolution codes Modules for Experiments in Stellar Astrophysics (MESA) and Single Star Evolution (SSE) with standard prescriptions for mass loss and stellar tides to predict the resulting population of white dwarfs and their substellar companions. Results. We find that the predicted fraction of white dwarfs hosting substellar companions in the Milky Way is, independent of uncertainties related to initial distributions, stellar tides, or stellar mass loss during the asymptotic giant branch, below ∼3 ± 1.5%. The occurrence rate peaks at relatively low-mass (∼0.53M⊙ to ∼0.66 M⊙ ) white dwarfs and relatively young (∼1–6 Gyr) systems, where it can reach >∼3%. The semimajor axes of the surviving companions range from 3–24 au with a median of 11 au. We estimate that ∼95% of the predicted companions are gas-giant planets, which translates to a predicted general Jupiter-like planet occurrence rate around white dwarfs below ∼2.9 ± 1.4%. These occurrence rates might slightly increase if multi-planetary systems are considered. Furthermore, owing to the strong dependence of companion occurrence on the metallicity of the white dwarf progenitor, the assumed age–metallicity relation strongly affects the predictions. Based on recent estimates of the local age–metallicity relation, we estimate that the fraction of white dwarfs with companions close to the Sun might reach <∼8%. Conclusions. If the planetary and brown dwarf companion distributions derived from intermediate-mass giant stars through radial velocity surveys reflect the characteristics of the true population, less than 3 ± 1.5% of white dwarfs host substellar companions. Depending somewhat on the age–metallicity relation, this most likely represents an upper limit on possible detections because a significant number of companions might not be detectable with current facilities.

New self-consistent theoretical descriptions for mass-loss rates of O-type stars

2026-06-11T20:24:46Z

Articulo Astronomy & Astrophysics; vol. 707 Context. Massive O-type stars lose a significant fraction of their mass through radiation-driven winds, a process that critically shapes their evolution and feedback into the interstellar medium. Accurate predictions of mass-loss rates ( Ṁ) are essential for models of stellar structure and population synthesis. Aims. We computed wind parameters for O-type stars using a self-consistent approach that couples the hydrodynamics of the wind with detailed calculations of the line acceleration. This approach follows the theory of radiation-driven stellar winds and, thus, allows us to derive mass-loss rate distributions for different atomic configurations of the stellar flux. Methods. We used the TLUSTY code for stellar atmosphere models to compute tailored non-local thermodynamic equilibrium mod- els; these models served as input radiation fields for the calculation of the force multiplier factor and the line-force parameters, for which we used the LOCUS code. These line-force parameters were then iteratively coupled with the HYDWIND code to solve the wind hydrodynamics. The procedure was repeated until convergence and applied across a grid of stellar parameters for three chemical configurations. Results. We obtain self-consistent wind parameters for a broad set of O-type stellar models. The results show a systematic decrease in mass-loss rates with the inclusion of more elements in the radiation field, which is attributed to a strong effect on the UV region of the spectral energy distribution. As more elements are included, resulting in a larger number of spectral lines, the contribution from the UV diminishes, leading to lower mass-loss rates. We fitted three theoretical prescriptions for Ṁ using a Bayesian approach; this yielded Pearson correlation values greater than 0.92 for all three model grids. It also allowed for the estimation of the wind momentum-luminosity relationships for each of the grids, yielding results similar to those based on observations of O-type stars.

On the Possibility of Chemically Driven Convection in Red Giants: Implications for the He-core Flash and Mixing above the Red Giant Branch Bump

2026-06-11T20:24:47Z

Articulo The Astrophysical Journal; vol. 1003, no. 1 Turbulent mixing remains one of the primary uncertainties in the modeling of stellar interiors. In stellar evolution simulations, regions where mixing occurs are typically identified using instability criteria. A particularly interesting situation arises when nuclear reactions produce inversions in the mean molecular weight within stellar interiors. Under these conditions, the material can become unstable to either thermohaline or Rayleigh–Taylor instabilities. We demonstrate that the standard criterion adopted in stellar evolution calculations does not accurately distinguish between these two regimes. We derive an alternative criterion and show that chemically driven convection in stellar interiors might be viable under much smaller mean molecular weight inversions than it is normally assumed. We investigate whether inversions in the mean molecular weight can trigger chemically driven convection above the red giant branch bump (RGBB) or during the helium-core flash. We find that the inversion at the base of the convective envelope above the RGBB is too weak and short-lived to sustain steady- state convection. In contrast, rapid carbon production at the base of the He-flash-driven convective zone can maintain a steady chemically driven convective region. This process could significantly alter our understanding of the He-core flash and warrants further study.

Impact of stellar rotation on type II supernova progenitor masses determined from pre-explosion imaging

2026-06-09T20:25:05Z

Articulo Astronomy & Astrophysics; vol. 709 The initial masses of red supergiant type II supernova (SN II) progenitors are commonly inferred from pre-explosion imaging by converting the progenitor luminosity into an initial mass estimate using non-rotating stellar evolution models. However, stellar rotation affects the evolution and may influence these estimates. We investigated how the observed distribution of rotational velocities in massive stars influences the progenitor initial masses of SNe II inferred from pre-SN imaging. We compared initial mass estimates obtained from non-rotating models with those derived from rotating models, in which the initial rotational velocities of the stellar models are sampled from the observed distribution. We analysed the inferred progenitor initial masses by (i) comparing the results for each SN individually, (ii) examining the overall probability density function, (iii) constructing the cumulative distribution function, and (iv) determining the upper initial-mass boundary. In all cases, the distributions obtained from rotating models are slightly shifted towards lower masses, although the differences remain smaller than the typical uncertainties. When using the observed distribution of initial rotational velocities for massive stars, we infer an upper initial-mass limit for SN II progenitors of 20.4+2.3 −1.9 M . Taken together, these analyses demonstrate that stellar rotation has only a modest impact on progenitor mass estimates from pre-SN imaging within the current observational and model uncertainties when the observed distribution of initial rotational velocities is taken into account. Therefore, adopting this distribution leads to small differences compared to non-rotating models.

The PAIRS project: a global formation model for planets in binaries: I. Effect of disc truncation on the growth of S-type planets

2026-06-09T20:25:06Z

Articulo Astronomy & Astrophysics; no. 708 Binary stars are as common as single stars. The number of detected planets orbiting binaries is rapidly increasing thanks to the synergy between transit surveys, Gaia, and high-resolution direct-imaging campaigns. However, global planet formation models around binary stars are still underdeveloped, which limits the theoretical understanding of planets orbiting binary star systems. We introduce the PAIRS project, which aims to build a global planet formation model for planets in binaries and to produce a planet population synthesis to statistically compare theory and observations. In this first paper, we present the adaptation of the circumstellar disc to simulate the formation of S-type planets. The presence of a secondary star tidally truncates and heats the outer part of the circumprimary disc (and vice versa for the circumsecondary disc), limiting the material to form planets. We implemented and quantified this effect for a range of binary parameters by adapting the Bern Model of planet formation in its pebble-based form and for in situ planet growth. We find that disc truncation has a strong impact on reducing the pebble supply for core growth and steadily suppresses planet formation for binary separations below 160 a when all the formed planets more massive than Mars are considered. Moreover, S-type planets tend to form close to the central star with respect to the binary separation and disc truncation radius. Our newly developed model will be the basis of future S-type planet population synthesis studies.

Local mixing length theory with compositional effects: first application to asymptotic giant branch evolution

2026-06-05T20:23:53Z

Articulo Astronomy & Astrophysics; vol. 705 Context. During the evolution of stars on the asymptotic giant branch (AGB), thermal pulses lead to the formation of strongly stratified layers in the outer regions of the CO core, which might lead to inversions in the chemical gradient. Such inversions would produce instabilities beyond the ones predicted by the Schwarzschild criterion and the standard use of mixing length theory (MLT). Aims. We aim to broaden the scope of MLT in a simple way to consider Rayleigh-Taylor and thermohaline instabilities. We also want to explore the impact of such instabilities during the AGB phase and in the pulsational properties of variable PG1159 (GW Vir) stars. Methods. We used a set of MLT equations that consider the impact of the background chemical gradients. This extension of MLT is referred to in this work as MLT], to make a distinction between both prescriptions. We applied MLT# in tandem with the more general Ledoux instability criterion. We computed the evolution in the AGB phase and compared the chemical profiles resulting from MLT, MLT# and the double diffusive GNA theory. We continued the evolution through a post-AGB thermal pulse and performed a pulsational analysis of the resultant GW Vir models to asses g-mode pulsation periods. Finally, we tested our results with pulsation properties of known GW Vir stars derived from recent observations. Results. We find that the much simpler MLT# set of equations closely reproduces the results from the GNA theory. As such, MLT# offers a simple way to include chemically driven convection in stellar evolution computations. Stellar evolution simulations show that Rayleigh-Taylor and thermohaline instabilities can play an important role during the TP-AGB. We obtained significantly different chemical profiles using a standard MLT approach compared to those resulting from our MLT# and GNA computations. Our adiabatic pulsational analysis shows that these differences in the chemical stratification leave clear mode-trapping signatures in the pulsation spectrum of the GW Vir models. Even though the comparison with current available GW Vir pulsation periods does not conclusively favor any of the three models of mixing explored in this work, our analysis demonstrates that asteroseismology of GW Vir stars has significant potential for probing chemically driven mixing processes during the TP-AGB phase.

Light curves from symmetric, polytropic contact binaries

2026-03-13T04:20:13Z

Articulo Monthly Notices of the Royal Astronomical Society; vol. 527, no. 4 We study the structure of contact binaries assuming a polytropic relation between pressure and density, restricting ourselves to the case of equal-mass components, i.e. symmetric contact binaries. In this case, matter is at rest in the corotating reference frame making this problem far simpler than the general case of non-symmetric contact binaries. We compute these structures assuming values of the polytropic index of n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 employing a self-consistent technique due to Hachisu. As a part of the results, we ﬁnd the shape of their surfaces. While for the case of n = 3.5, such surfaces are very close to those corresponding to equipotentials of the restricted Lagrangian three-body problem, for lower n values the departure is remarkable. We propose a generalized function to ﬁt these surfaces, which allows us to perform an accurate integration of the light curve due to the object. Then, for values of n > 0.0 we computed a family of light curves considering different inclinations and values for the width of the neck connecting the components (or equivalently, the ﬁllout factor) of the pair. We compare our calculations with the solution found for the symmetric contact binary V803 Aquilae by employing the popular PHOEBE code, that assumes the above-mentioned Lagrangian equipotential surfaces. We conclude that considering polytropic structures leads to parameters that may be appreciably different from those deduced by assuming that their surfaces correspond to equipotentials of the restricted three-body problem.

Unveiling a new extragalactic structure hidden by the Milky Way

2026-03-13T04:20:14Z

Articulo Astronomy & Astrophysics; vol. 669 Context. The zone of avoidance (ZoA) does not allow for clear optical observations of extragalactic sources behind the Milky Way due to the meaningful extinction of the optical emission of these objects. Observations in near-infrared (NIR) wavelengths represent a potential source of astronomical discoveries that support the detection of new galaxies and potentially complete the picture of the large-scale structures in this as-yet poorly explored area of the sky. Aims. Our aim is to decipher the nature of the overdensity located behind the Milky Way in tile b204 of the VISTA Variables in Vía Láctea (VVV) survey. Methods. We studied an area of six arcmin around a galaxy concentration located at l = 354.82° and b = −9.81°. We selected five galaxies, taking into account the source distribution on the sky to optimise the requested time for the observations, and we obtained the spectra with Flamingos 2 long-slit spectrograph at Gemini South 8.1-meter telescope. To identify and characterise the absorption features, we fit the galaxies underlying spectrum using the STARLIGHT code together with the IRTF stellar library. In addition, the spectroscopic findings are reinforced using complementary photometric techniques such as red-sequence and photometric redshift estimation. Results. The mean spectroscopic redshift estimated from the NIR spectra is z = 0.225 ± 0.014. This value presents a good agreement with that obtained from photometric analysis, photoz = 0.21 ± 0.08, and the probability distribution function of the galaxies in the studied region. Also, the red-sequence slope is consistent with the one expected for NIR observations of galaxy clusters. Conclusions. The redshifts obtained from both, photometric and spectroscopic techniques are in good agreement, allowing for the confirmation of the nature of this structure at z = 0.225 ± 0.014, thereby unveiling a new galaxy cluster, VVVGCl-B J181435-381432, behind the Milky Way bulge.

The Ophiuchus DIsc Survey Employing ALMA (ODISEA) – I: project description and continuum images at 28 au resolution

2026-03-13T04:20:15Z

Articulo Monthly Notices of the Royal Astronomical Society; vol. 482, no. 1 We introduce the Ophiuchus DIsc Survey Employing ALMA (ODISEA), a project aiming to study the entire population of Spitzer-selected protoplanetary discs in the Ophiuchus Molecular Cloud (∼300 objects) from both millimetre continuum and CO isotopologues data. Here we present 1.3 mm/230 GHz continuum images of 147 targets at 0.2 arcsec (28 au) resolution and a typical rms of 0.15 mJy. We detect a total of 133 discs, including the individual components of 11 binary systems and 1 triple system. 60 of these discs are spatially resolved. We find clear substructures (inner cavities, rings, gaps, and/or spiral arms) in eight of the sources and hints of such structures in another four discs. We construct the disc luminosity function for our targets and perform preliminary comparisons to other regions. A simple conversion between flux and dust mass (adopting standard assumptions) indicates that all discs detected at 1.3 mm are massive enough to form one or more rocky planets. In contrast, only ∼50 discs (∼1/3 of the sample) have enough mass in the form of dust to form the canonical 10 M⊕ core needed to trigger runaway gas accretion and the formation of gas giant planets, although the total mass of solids already incorporated into bodies larger than cm scales is mostly unconstrained. The distribution in continuum disc sizes in our sample is heavily weighted towards compact discs: most detected discs have radii < 15 au, while only 23 discs (∼15 per cent of the targets) have radii > 30 au. La lista completa de autores que integran el documento puede consultarse en el archivo.

Two Decades of Dust Evolution in SN 2005af through JWST, Spitzer, and Chemical Modeling

2025-12-29T20:32:11Z

Articulo The Astrophysical Journal; vol. 993, no. 1 The evolution of dust in core-collapse supernovae (SNe), in general, is poorly constrained owing to a lack of infrared observations a few years after explosion. Most theories of dust formation in SNe heavily rely only on SN 1987A. In the last two years, the James Webb Space Telescope (JWST) has enabled us to probe the dust evolution in decades-old SNe, such as SN 2004et, SN 2005ip, and SN 1980K. In this paper, we present two decades of dust evolution in SN 2005af, combining early-time infrared observations with the Spitzer Space Telescope and recent detections by the JWST. We have used a chemical kinetic model of dust synthesis in SN ejecta to develop a template of dust evolution in SN 2005af. Moreover, using this approach, for the first time, we have separately quantified the dust formed in the pre-explosion wind that survived after the explosion and the dust formed in the metal-rich SN ejecta post-explosion. We report that in SN 2005af, predominantly carbon-rich dust formed in the ejecta, with a total mass of at least 0.02M⊙. In the circumstellar medium, the surviving oxygen-rich dust amounts to about (3–6) × 10−3M⊙, yielding a total dust mass of at least 0.025 M⊙. La lista completa de autores que integran el documento puede consultarse en el archivo.

Multiperiodic Pulsations of the Unique DAQ White Dwarf J0551+4135: Insights into a Merger Remnant

2025-12-29T20:32:12Z

Articulo The Astrophysical Journal; vol. 995, no. 1 2MASS J05513444+4135297 (hereafter J0551+4135) is the only pulsating DAQ white dwarf (WD) known with a carbon and hydrogen atmosphere. Its unusual atmospheric composition and kinematics indicate a WD merger origin. We present time-series photometry of J0551+4135 obtained using the Apache Point Observatory 3.5 m, Gemini North 8 m, and Gran Telescopio Canarias 10 m telescopes. J0551+4135 exhibits variations in pulsation amplitude and frequency over time. We detect 10 significant recurring peaks across different subsets of observations, with frequencies ranging from 987 to 1180 μHz, consistent with nonradial gravity (g)-mode oscillations. We present new evolutionary models suitable for spectroscopic characterization of DAQ WDs, and derive a mass of 1.13 ± 0.01M⊙and a cooling age of 1.7 ± 0.1 Gyr for a CO core, and 1.12 ± 0.01M⊙and 1.6 ± 0.1 Gyr for an ONe-core WD, respectively. However, detailed asteroseismology of this unique pulsator has to wait until fully consistent DAQ evolutionary models are available. Further observations, including multisite campaigns to reduce daily aliasing and to improve the signal-to-noise ratio, would be helpful for the identification of additional modes and constraining the internal structure of this unique pulsator.

Discovery of the Richest Pulsating Ultramassive White Dwarf

2025-12-27T04:30:57Z

Articulo The Astrophysical Journal Letters; vol. 980. no. 1 The discovery of pulsations in ultramassive (UM) white dwarfs (WDs) can help to probe their interiors and unveil their core composition and crystallized mass fraction through asteroseismic techniques. To date, the richest pulsating UM WD known is BPM 37093 with 8 modes detected, for which detailed asteroseismic analysis has been performed in the past. In this work, we report the discovery of 19 pulsation modes in the UM WD star WDJ0135 +5722, making it the richest pulsating hydrogen-atmosphere UM WD known to date. This object exhibits multiperiodic luminosity variations with periods ranging from 137 to 1345 s, typical of pulsating WDs in the ZZ Ceti instability strip, which is centered at Teff ∼ 12,000 K. We estimate the stellar mass of WDJ0135+5722 by different methods, resulting in M★ ∼ 1.12–1.14 M☉ if the star’s core is made of oxygen and neon or M★ ∼ 1.14–1.15 M☉ if the star hosts a carbon oxygen core. Future analysis of the star periods could shed light on the core chemical composition through asteroseismology.

Quantifying the Impact of the Dust Torque on the Migration of Low-mass Planets. II: the Role of Pebble Accretion in Planet Growth within a Global Planet Formation Model

2025-07-17T20:11:09Z

Articulo The Astrophysical Journal; vol. 986, no. 2 Although dust constitutes only about 1% of the mass in a protoplanetary disk, recent studies reveal its substantial impact on the torques experienced by low- and intermediate-mass planetary cores. In this study, we present the first comprehensive analysis of the dust torque’s influence on the evolution of growing planetary embryos as they migrate through a protoplanetary disk and undergo gas and pebble accretion. Our global model incorporates viscous accretion and X-ray photoevaporation effects on the gaseous disk while also accounting for the dynamic processes of dust growth and evolution, including coagulation, drift, and fragmentation. Our >fidings demonstrate that dust torque significantly affects planetary migration patterns, particularly facilitating prominent outward migration for planets forming within the water-ice line. This outward thrust arises from an enhanced dust-to-gas mass ratio in the inner disk, driven by the inward drift of pebbles from the outer regions. Conversely, for planets that originate beyond the water-ice line, while the dust torque attenuates inward migration, it does not substantially alter their overall migration trajectories. This is attributed to the rapid reduction in dust-to-gas mass ratio, resulting from swift pebble drift and the short formation timescales prevalent in that region. Overall, our findings highlight the critical role of dust torque in shaping the migration of low- and intermediate-mass planets, particularly in conditions where increased dust concentrations amplify its effects. These insights have significant implications for understanding the formation timescales, mass distributions, and compositional characteristics of emerging planetary systems.

Powerful Radio Sources in the Southern Sky: II. A Swift X-Ray Perspective

2024-07-03T20:05:08Z

Articulo The Astrophysical Journal Supplement Series; vol. 268, no. 1 We recently constructed the G4Jy-3CRE, a catalog of extragalactic radio sources based on the GLEAM 4-Jy (G4Jy) sample, with the aim of increasing the number of powerful radio galaxies and quasars with similar selection criteria to those of the revised release of the Third Cambridge Catalog (3CR). The G4Jy-3CRE consists of a total of 264 radio sources mainly visible from the Southern Hemisphere. Here, we present an initial X-ray analysis of 89 G4Jy-3CRE radio sources with archival X-ray observations from the Neil Gehrels Swift Observatory. We reduced a total of 624 Swift observations, for about 0.9 Ms of integrated exposure time. We found X-ray counterparts for 59 radio sources belonging to the G4Jy-3CRE, nine of them showing extended X-ray emission. The remaining 30 sources do not show any X-ray emission associated with their radio cores. Our analysis demonstrates that X-ray snapshot observations, even if lacking uniform exposure times, as those carried out with Swift, allow us to (i) verify and/or refine the host galaxy identification; (ii) discover the extended X-ray emission around radio galaxies of the intracluster medium when harbored in galaxy clusters, as the case of G4Jy 1518 and G4Jy 1664; and (iii) detect X-ray radiation arising from their radio lobes, as for G4Jy 1863. La lista completa de autores que integran el documento puede consultarse en el archivo.

Powerful Radio Sources in the Southern Sky. III. First Results of the Optical Spectroscopic Campaign

2024-07-03T20:05:11Z

Articulo The Astrophysical Journal Supplement Series; vol. 271, no. 1 We recently built the G4Jy-3CRE catalog of extragalactic radio sources. This catalog lists 264 powerful radio sources selected with similar criteria to those of the revised Third Cambridge Catalog, but visible from the Southern Hemisphere. A literature search revealed that 119 sources in the G4Jy-3CRE catalog (i.e., 45%) lack a firm spectroscopic redshift measurement. Here, we present a campaign aimed at acquiring optical spectra of G4Jy- 3CRE sources and measuring their redshifts. We used single-slit observations obtained with the Víctor Blanco Telescope, the New Technology Telescope, the Southern Astrophysical Research Telescope, and the 2.1 m telescope of the Observatorio Astronómico Nacional at San Pedro Mártir, Mexico. In addition, we analyzed Very Large Telescope/MUSE archival observations. From these observations, we report the spectra and redshifts of 93 sources, 42 of which are the first optical spectra and redshift determinations for the respective sources. With our new data, approximately 71% of the sources in the G4Jy-3CRE catalog now have firm spectroscopic redshift measurements. This data set will be the basis of our future analysis of the optical properties of the G4Jy-3CRE catalog. La lista completa de autores que integran el documento puede consultarse en el archivo.

Radio Jet Feedback on the Inner Disk of Virgo Spiral Galaxy Messier 58

2024-06-27T20:04:58Z

Articulo The Astrophysical Journal; vol. 962, no. 2 Spitzer spectral maps reveal a disk of highly luminous, warm (>150 K) H2 in the center of the massive spiral galaxy Messier 58, which hosts a radio-loud active galactic nucleus (AGN). The inner 2.6 kpc of the galaxy appears to be overrun by shocks from the radio jet cocoon. Gemini NIRI imaging of the H2 1–0 S(1) emission line, Atacama Large Millimeter/submillimeter Array CO 2–1, and Hubble Space Telescope multiband imagery indicate that much of the molecular gas is shocked in situ, corresponding to lanes of dusty molecular gas that spiral toward the galactic nucleus. The CO 2–1 and ionized gas kinematics are highly disturbed, with velocity dispersion up to 300 km s−1. Dissipation of the associated kinetic energy and turbulence, likely injected into the interstellar medium by radio-jet-driven outflows, may power the observed molecular and ionized gas emission from the inner disk. The polycyclic aromatic hydrocarbon (PAH) fraction and composition in the inner disk appear to be normal, in spite of the jet and AGN activity. The PAH ratios are consistent with excitation by the interstellar radiation field from old stars in the bulge, with no contribution from star formation. The phenomenon of jet-shocked H2 may substantially reduce star formation and help to regulate the stellar mass of the inner disk and supermassive black hole in this otherwise normal spiral galaxy. Similarly strong H2 emission is found at the centers of several nearby spiral and lenticular galaxies with massive bulges and radio-loud AGNs. La lista completa de autores puede verse en el archivo asociado.

Optical Spectroscopy of Type Ia Supernovae by the Carnegie Supernova Projects I and II

2024-06-27T20:05:03Z

Articulo The Astrophysical Journal; vol. 967, no. 1 We present the second and final release of optical spectroscopy of Type Ia supernovae (SNe La) obtained during the first and second phases of the Carnegie Supernova Project (CSP-I and CSP-II). The newly released data consist of 148 spectra of 30 SNe Ia observed in the course of CSP-I and 234 spectra of 127 SNe Ia obtained during CSP-II. We also present 216 optical spectra of 46 historical SNe Ia, including 53 spectra of 30 SNe Ia observed by the Calán/Tololo Supernova Survey. We combine these observations with previously published CSP data and publicly available spectra to compile a large sample of measurements of spectroscopic parameters at maximum light, consisting of pseudo-equivalent widths and expansion velocities of selected features for 232 CSP and historical SNe Ia (including more than 1000 spectra). Finally, we review some of the strongest correlations between spectroscopic and photometric properties of SNe Ia. Specifically, we define two samples: one consisting of SNe Ia discovered by targeted searches (most of them CSP-I objects) and the other composed of SNe Ia discovered by untargeted searches, which includes most of the CSP-II objects. The analyzed correlations are similar for both samples. We find a larger incidence of SNe Ia belonging to the cool and broad-line Branch subtypes among the events discovered by targeted searches, shallow-silicon SNe Ia are present with similar frequencies in both samples, while core normal SNe Ia are more frequent in untargeted searches. La lista completa de autores puede verse en el archivo asociado.

The internal kinematic of star-forming regions in interacting galaxies

2024-06-25T20:04:59Z

Objeto de conferencia II Workshop on Chemical Abundances in Gaseous Nebulae: Open problems in Nebular Astrophysics (Brasil, 11 al 14 de marzo de 2019); Chemical abundances in gaseous nebulae: open problems in nebular astrophysics Star formation processes can be found in colliding galaxies, where the gas compression can trigger the formation of giant star-forming regions. We present the results from a detailed kinematic analysis in a sample of HII regions located in three strongly interacting galaxies. The velocity dispersion and the luminosity of the multiple-components analyzed in the emission-line profiles suggest that these star-forming objects correspond to giant complexes. In addition, the star formation rates and the ionization state in these regions revealed the presence of ongoing star formation events.