Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>We are conducting a multi-wavelength analysis of high-resolution molecular spectra that probe the evolution of gas in the inner 10 au in protoplanetary disks. A sample of 15 disks has been combined to probe a range of inner disk structures including small and large dust cavities. Half of the sample has been observed in far-ultraviolet H<jats:sub>2</jats:sub> emission with a new HST-COS program (GO-14703), that we have combined to near-infrared spectra of CO emission as observed with VLT-CRIRES and IRTF-iSHELL. This synergic dataset traces the evolution and depletion of CO and H<jats:sub>2</jats:sub> in inner disk cavities and shows an evolving radial stratification of the molecular gas, where CO lines are narrower than H<jats:sub>2</jats:sub> lines in disks with cavities. CO rotation diagrams also show significant evolution, suggesting a change in gas excitation as CO emission recedes to larger disk radii.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Exoplanets are planets that orbit stars other than our Sun, and the most common way of detecting them is by the transit method. This method consists of plotting the relative brightness of the exoplanets host star against a comparison star to make what is known as a light curve. Periodic dips in the light curve could correspond to the exoplanet coming in front of its host star, and blocking some of its light. One time of great importance to constantly keep up to date is the exoplanets mid-transit time. The mid-transit time is the time in which the exoplanet is in the middle of its transit; however, the problem with this value is that it changes over many periods due to the uncertainty in the period of the planet. Thus, it is important to update transit timings as incorrect timings can hinder observations from expensive telescopes. Crowdsourcing exoplanet transit analysis is a great opportunity to help these large telescopes and get the community involved in exoplanet research. In this study, six citizen scientists from the East Bay Astronomical Society (EAS) performed a transit analysis of HATS-4 b using the Exoplanet Transit Interpretation Code (EXOTIC). Using newly calculated mid-transit times, we were able to see how off the expected mid-transit time based on the existing mid-transit time on the NASA Exoplanet Archive was by calculating the phase difference.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We are conducting a survey of high-resolution near-infrared CO rovibrational spectra in protoplanetary disks around young intermediate-mass stars. We use IRTF-iSHELL with the 0.″375 and 0.″75 slits, providing 4 km s<jats:sup>−1</jats:sup> and 6 km s<jats:sup>−1</jats:sup> resolution and covering 4.52–5.25 <jats:italic>μ</jats:italic>m in one single exposure. This includes part of the rovibrational R branch and most of the P branch of the CO fundamental band (Δ<jats:italic>v</jats:italic> = 1), one of the best tracers of warm/hot gas in disks. The high quality of the spectra and the large sample covered in this survey will support multiple investigations to study the structure, kinematics, composition, and evolution of the inner 10 au in disks for years to come. The survey currently includes ∼30 stars mostly within 200 pc, complementing extensive imaging campaigns that are observing their disks at optical, infrared, and millimeter wavelengths and revealing structures and planets.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Evidence is presented that the far ultraviolet flux of Maia recorded by the International Ultraviolet Explorer is variable over a timescale of a few hours. In contrast, the radial velocity of the Si <jats:sc>ii</jats:sc> doublet near 1530 Å does not vary on short timescales.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Mechanical feedback from young massive stars in super star clusters contributes to the formation of superwinds and superbubbles in star-forming regions. We conduct hydrodynamic simulations using the non-equilibrium ionization package <jats:sc>maihem</jats:sc> to explore how outflow velocity, mass-loading, metallicity, and ambient density can affect the occurrence of catastrophic cooling. To predict optical and UV emission lines, we apply the photoionization code <jats:sc>cloudy</jats:sc> to the physical conditions predicted by our hydrodynamic simulations. Our results could be useful for characterizing catastrophic cooling in starburst regions like the nearby Green Peas and distant star-forming galaxies.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In the study of large astronomical data sets, virtual reality (VR) can help build valuable spatial intuition for scientific discovery. We created VR visualizations of E+A galaxies and candidates in four nearby clusters of galaxies: Leo, Virgo, Hercules, and Coma. E+A's are a type of post-starburst galaxy in which all star formation has been recently (∼1 Gyr ago) quenched. Our E+A samples were assembled and cataloged by the Y/Dim collaboration through visual and quantitative analysis of SDSS DR16 spectra. The visualizations are designed for Oculus VR headsets, and utilize C# scripts which interface with the Unity engine, including public domain code and code developed by the lead author. We use these visualizations to find features of the aforementioned galaxy clusters: for instance, a “nose” of low velocity objects in the center of the Virgo cluster and a collection of E+A candidates along a galactic filament in the Coma cluster.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Coma Berenices (Coma Ber), an open cluster about the same age as Praesepe and the Hyades (700–800 Myr) is, despite being only 85 pc away, less well studied than its famous cousins. This is due principally to its sparseness and low proper motion, which together made Coma Ber’s membership challenging to establish pre-Gaia. We have curated a new list of its members based on Gaia DR2 astrometry, derived its metallicity and interstellar reddening using LAMOST data, and inferred the cluster’s age by fitting PARSEC isochrones to its color–magnitude diagram. We then measured rotation periods for Coma Ber’s low-mass members using TESS and ZTF photometry. Our isochrone fitting and the TESS- and ZTF-derived rotation periods confirm that Coma Ber is coeval with the Hyades and Praesepe. This work is the first step toward re-establishing Coma Ber as another valuable benchmark cluster for age–rotation–activity studies.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present low-resolution spectra collected with the Spectral Energy Distribution Machine (SEDM) for an IW And-type dwarf nova, HO Puppis, and a Be star, V722 Tauri. The SEDM is an integrated field unit spectrograph mounted on the 60 inch telescope at the Palomar Observatory, with a spectral resolution of <jats:italic>R</jats:italic> ∼ 100 in the optical wavelength range. The H<jats:italic>α</jats:italic> emission line was clearly detected for the bright Be star V722 Tauri at ∼12.5 mag, but barely detected in the spectra for the ∼13.7 mag HO Puppis. Our SEDM observations could be used as guidance for observing similar objects with the SEDM, as well as other <jats:italic>R</jats:italic> ∼ 100 spectrographs, in the future.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We compare features from the circulation model developed in Stȩpień for contact binaries to a long-term hydrodynamical evolution of a symmetric contact binary. The numerical evolution is fully three-dimensional and begins from an equilibrium structure in contact at one grid cell. As the evolution is conducted with Flow-ER, an explicit hydrodynamics code for self-gravitating fluids, we are not able to address energy transport or evolution on a thermal timescale. However, we are able to investigate the width and height of the equatorial accretion belt and the flow of material in and out of the inner Lagrange point. The flow of material between the two components arises quickly in the evolution and does not change significantly through tens of orbital periods. As the stellar components are modeled as polytropes of index 3/2 a slight numerical mass imbalance causes one component to only gain mass over the course of the simulation leading eventually to a dynamical merger of the contact binary.</jats:p>