Search Publications
Multiwavelength Observations of MWC 297: Constraints on Disk Inclination and Mass Outflow
Vacca, William D.; Sandell, Göran
MWC 297 is a young, early-type star driving an ionized outflow and surrounded by warm, entrained dust. Previous analyses of near- and mid-IR interferometric images suggest that the emission at these wavelengths arises from a compact accretion disk with a moderate (i < 40°) inclination. We have obtained 5-40 µm images of MWC 297 with FORCA…
Quantifying Chemical and Kinematical Properties of Galactic Disks
Hu, Guozhen; Shao, Zhengyi
We aim to quantify the chemical and kinematical properties of Galactic disks with a sample of 119,558 giant stars having abundances and 3D velocities taken or derived from the APOGEE DR17 and Gaia EDR3 catalogs. A Gaussian mixture model is employed to distinguish the high-α and low-α sequences along the metallicity by simultaneously using chemical…
Measuring the Nonaxially Symmetric Surface Temperature Distribution of the Central Compact Object in Puppis A
Gotthelf, E. V.; Halpern, J. P.; Perna, R. +1 more
The surface temperature distributions of central compact objects (CCOs) are powerful probes of their crustal magnetic field strengths and geometries. Here we model the surface temperature distribution of RX J0822-4300, the CCO in the Puppis A supernova remnant, using 471 ks of XMM-Newton data. We compute the energy-dependent pulse profiles in 16 e…
Detection of a Superluminous Spiral Galaxy in the Heart of a Massive Galaxy Cluster
Lovisari, Lorenzo; Ogle, Patrick; Jones, Christine +5 more
It is well established that brightest cluster galaxies (BCGs), residing in the centers of galaxy clusters, are typically massive and quenched galaxies with cD or elliptical morphology. An optical survey suggested that an exotic galaxy population, superluminous spiral and lenticular galaxies, could be the BCGs of some galaxy clusters. Because the c…
Recent Formation of a Spiral Disk Hosting Progenitor Globular Clusters at the Center of the Perseus Brightest Cluster Galaxy. I. Spiral Disk
Ohyama, Youichi; Lim, Jeremy; Yeung, Michael C. H.
We address the nature and origin of a spiral disk at the center of NGC 1275, the giant elliptical galaxy at the center of the Perseus cluster, that spans a radius of ~5 kpc. By comparing stellar absorption lines measured in long-slit optical spectra with synthetic spectra for single stellar populations, we find that fitting of these lines requires…
A GMOS/IFU Study of Jellyfish Galaxies in Massive Clusters
Lee, Myung Gyoon; Lee, Jeong Hwan; Kang, Jisu +2 more
Jellyfish galaxies are an intriguing snapshot of galaxies undergoing ram pressure stripping (RPS) in dense environments, showing spectacular star-forming knots in their disks and tails. We study the ionized gas properties of five jellyfish galaxies in massive clusters with Gemini GMOS/Integral Field Unit observations: MACSJ0916-JFG1 (z = 0.330), M…
Improved Model of X-Ray Emission from Hot Accretion Flows
Zdziarski, Andrzej A.; Szanecki, Michał; Niedźwiecki, Andrzej +1 more
We have developed an improved model of X-ray emission from optically thin, two-temperature accretion flows, kerrflow, using an exact Monte Carlo treatment of global Comptonization as well as with a fully general relativistic description of both the radiative and hydrodynamic processes. It also includes pion-decay electrons, whose synchrotron emiss…
Catching the Butterfly and the Homunculus of η Carinae with ALMA
Gull, Theodore R.; Menten, Karl M.; Toalá, Jesús A. +7 more
The nature and origin of the molecular gas component located in the circumstellar vicinity of η Carinae are still far from being completely understood. Here, we present Atacama Large Millimeter/submillimeter Array CO(3-2) observations with a high angular resolution (~0.″15) and a great sensitivity that are employed to reveal the origin of this com…
Estimating the Injection Duration of 20 MeV Protons in Large Western Solar Energetic Particle Events
Lugaz, Noé; Li, Gen
An ad hoc analytical calculation is presented to infer the duration of injection of 20 MeV protons in 21 selected western solar energetic particle (SEP) events. We convolve the solution of diffusion equation with a "triangle" source to model the time-intensity profiles over the onset and the peaking phase. The effects of "corotating" flux tubes an…
Modeling the Photometric Variability of Alpha2 CVn with a Dynamical Magnetosphere
Pfeffer, Cameron M.; McSwain, M. Virginia
Alpha2 Canum Venaticorum (α 2 CVn) is a strongly magnetic star with peculiar chemical signatures and periodic variability that have been long attributed to the diffusion of magnetic elements through the photosphere, leading to chemical spots across the stellar surface. However, recent studies of other magnetic hot stars are c…