Search Publications
First Assessment of the Binary Lens OGLE-2015-BLG-0232
Bennett, D. P.; Soszyński, I.; Udalski, A. +54 more
We present an analysis of the microlensing event OGLE-2015-BLG-0232. This event is challenging to characterize for two reasons. First, the light curve is not well sampled during the caustic crossing due to the proximity of the full Moon impacting the photometry quality. Moreover, the source brightness is difficult to estimate because this event is…
Electron Densities and Nitrogen Abundances in Ionized Gas Derived Using [N II] Fine-structure and Hydrogen Recombination Lines
Lazio, T. Joseph W.; Horiuchi, Shinji; Goldsmith, Paul F. +7 more
We present a method for deriving the electron density of ionized gas using the ratio of the intensity of the [N II] 205 µm line to that of hydrogen radio recombination lines (RRLs). We use this method to derive electron densities of 21 velocity components in 11 lines of sight through the Galaxy, including the Galactic center. We observed, at…
Member Stars of the GD-1 Tidal Stream from the SDSS, LAMOST, and Gaia Surveys
Huang, Y.; Chen, B. -Q.; Wang, C. +5 more
With the photometric data from the SDSS survey, the spectroscopic data from the SDSS/SEGUE and the LAMOST surveys, and the astrometric data from the Gaia DR2, we have identified 67 highly probable member stars of the GD-1 cold stellar stream spread along almost its entire length (i.e., from 126° to 203° in R.A.). With the accurate spectroscopic (i…
Carbon-deficient Red Giants
Bond, Howard E.
Carbon-deficient red giants (CDRGs) are a rare class of peculiar red giants, also called “weak G-band” or “weak CH” stars. Their atmospheric compositions show depleted carbon, a low {}12{{C}}{/}13{{C}} isotopic ratio, and an overabundance of nitrogen, indicating that the material at the surface has undergone CN-cycle hydrogen…
On Geometrical Invariants of the Magnetic Field Gradient Tensor in Turbulent Space Plasmas: Scale Variability in the Inertial Range
Marcucci, Maria Federica; Consolini, Giuseppe; Materassi, Massimo +1 more
In a recent paper, Consolini et al. investigated the statistics of geometrical invariants of the coarse-grained gradient tensor of plasma velocity for a case study of space plasma turbulence. They showed how, at spatial scales near the proton inertial length, there is evidence for the occurrence of dissipation structures along the Vieillefosse’s t…
Asymmetric Distribution of Weak Photospheric Magnetic Field Values
Mursula, Kalevi; Virtanen, Ilpo; Getachew, Tibebu
We use the synoptic maps of the photospheric magnetic field observed at Wilcox Solar Observatory, Mount Wilson Observatory, Kitt Peak, SOHO/MDI, SOLIS/VSM, and SDO/HMI to study the distribution of weak photospheric magnetic field values in 1974-2018. We fit the histogram distribution of weak field values for each synoptic map of the six data sets …
Measuring the Obscuring Column of a Disk Megamaser AGN in a Nearby Merger
Comastri, A.; Brusa, M.; Civano, F. +5 more
Active galactic nuclei (AGNs) hosting disk water megamasers are well known to be obscured by large amounts of gas, likely due to the presence along the line of sight of an almost edge-on disky structure orbiting the supermassive black hole. Correcting for the high obscuration is crucial to infer parameters intrinsic to the source, like its luminos…
Discovery of a Damped Lyα System in a Low-z Galaxy Group: Possible Evidence for Gas Inflow and Nuclear Star Formation
Heckman, Timothy M.; Tumlinson, Jason; Momjian, Emmanuel +3 more
We present a low-redshift (z = 0.029) damped Lyα (DLA) system in the spectrum of a background quasi-stellar object (QSO). The DLA is associated with an interacting galaxy pair within a galaxy group. We detected weak Lyα emission centered at the absorption trough of the DLA. The emission was likely tracing the neutral H I reservoir around the galax…
Catalog of High Protostellar Surface Density Regions in Nearby Embedded Clusters
Li, Juan; Myers, Philip C.; Kirk, Helen +3 more
We analyze high-quality stellar catalogs for 24 young and nearby (within 1 kpc) embedded clusters and present a catalog of 32 groups which have a high concentration of protostars. The median effective radius of these groups is 0.17 pc. The median protostellar and pre-main-sequence star surface densities are 46 M ⊙ pc-2 and 11…
T CrB: Radio Observations during the 2016-2017 “Super-active” State
Chomiuk, Laura; Sokoloski, Jennifer L.; Mukai, Koji +6 more
We obtained radio observations of the symbiotic binary and known recurrent nova T Coronae Borealis following a period of increased activity in the optical and X-ray bands. A comparison of our observations with those made prior to 2015 indicates that the system is in a state of higher emission in the radio as well. The spectral energy distributions…