Search Publications
Are Massive Dense Clumps Truly Subvirial? A New Analysis Using Gould Belt Ammonia Data
Caselli, Paola; Di Francesco, James; Rosolowsky, Erik +22 more
Dynamical studies of dense structures within molecular clouds often conclude that the most massive clumps contain too little kinetic energy for virial equilibrium, unless they are magnetized to an unexpected degree. This raises questions about how such a state might arise, and how it might persist long enough to represent the population of massive…
On a Possible Solution to the Tidal Realignment Problem for Hot Jupiters
Winn, Joshua N.; Penev, Kaloyan; Anderson, Kassandra R.
Hot stars with hot Jupiters have a wide range of obliquities, while cool stars with hot Jupiters tend to have low obliquities. An enticing explanation for this pattern is tidal realignment of the cool host stars, although this explanation assumes that obliquity damping occurs faster than orbital decay, an assumption that needs further exploration.…
Detection of a Multiphase Ultrafast Wind in the Narrow-line Seyfert 1 Galaxy Mrk 1044
Santos-Lleó, M.; Peterson, B. M.; Nicastro, F. +6 more
We present a detailed analysis of XMM-Newton X-ray spectra of the Narrow-Line Seyfert 1 galaxy Mrk 1044. We find robust evidence for a multiphase, ultrafast outflow, traced by four separate components in the grating spectrum. One component has high column density and ionization state, and is outflowing at ~0.15c. The other three wind components ha…
Solar Anti-Hale Bipolar Magnetic Regions: A Distinct Population with Systematic Properties
Muñoz-Jaramillo, Andrés; Campusano, Luis E.; Navarrete, Benjamín
Besides their causal connection with long and short-term magnetic variability, solar bipolar magnetic regions are our chief source of insight into the location, size, and properties of large-scale toroidal magnetic structures in the solar interior. The great majority of these regions (≈95%) follow a systematic east-west polarity orientation (Hale'…
X-Ray Constraint on the Location of the AGN Torus in the Circinus Galaxy
Tanimoto, Atsushi; Ueda, Yoshihiro; Kawamuro, Taiki +5 more
The location of the obscuring "torus" in an active galactic nucleus (AGN) is still an unresolved issue. The line widths of X-ray fluorescence lines originating from the torus, particularly Fe Kα, carry key information on the radii of line-emitting regions. Utilizing XCLUMPY, an X-ray clumpy torus model, we develop a realistic model of emission lin…
A New Identity Card for the Bulge Globular Cluster NGC 6440 from Resolved Star Counts
Vesperini, Enrico; Pallanca, Cristina; Dalessandro, Emanuele +6 more
We present a new identity card for the cluster NGC 6440 in the Galactic Bulge. We have used a combination of high-resolution Hubble Space Telescope images, wide-field ground-based observations performed with the ESO-FORS2, and the public survey catalog Pan-STARRS to determine the gravitational center, projected density profile, and structural para…
First Phase Space Portrait of a Hierarchical Stellar Structure in the Milky Way
Dalessandro, Emanuele; Saracino, S.; Bellazzini, M. +10 more
We present the first detailed observational picture of a possible ongoing massive cluster hierarchical assembly in the Galactic disk as revealed by the analysis of the stellar full phase space (3D positions and kinematics and spectro-photometric properties) of an extended area (6° diameter) surrounding the well-known h and χ Persei double stellar …
The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars
France, Kevin; Youngblood, Allison; Pineda, J. Sebastian
Accurate stellar properties are essential for precise stellar astrophysics and exoplanetary science. In the M-dwarf regime, much effort has gone into defining empirical relations that can use readily accessible observables to assess physical stellar properties. Often, these relations for the quantity of interest are cast as a nonlinear function of…
Understanding Polarized Dust Emission from ρ Ophiuchi A in Light of Grain Alignment and Disruption by Radiative Torques
Soam, Archana; Hoang, Thiem; Lee, Hyeseung +5 more
The alignment of dust grains with the ambient magnetic field produces polarization of starlight as well as thermal dust emission. Using the archival SOFIA/HAWC+ polarimetric data observed toward the ρ Ophiuchus (Oph) A cloud hosted by a B star at 89 and 154 µm, we find that the fractional polarization of thermal dust emission first increases…
Time and Charge-sign Dependence of the Heliospheric Modulation of Cosmic Rays
Potgieter, M. S.; Aslam, O. P. M.; Bisschoff, D. +4 more
Simultaneous and continuous observations of galactic cosmic-ray electrons (e-) and positrons (e+) from the PAMELA and AMS02 space experiments are most suitable for numerical modeling studies of the heliospheric modulation of these particles below 50 GeV. A well-established comprehensive three-dimensional modulation model is a…