Search Publications
High Resolution X-Ray Spectroscopy of the Local Hot Gas along the 3C 273 Sightline
Fang, Taotao; Jiang, Xiaochuan
X-ray observations of highly ionized metal absorption lines at z = 0 provide critical information on the hot gas distribution in and around the Milky Way. We present a study of more than 10 yr of Chandra and XMM-Newton observations of 3C 273, one of the brightest extragalactic X-ray sources. Compared with previous works, we obtain much tighter con…
Pre-flare Dynamics of Sunspot Groups
Korsós, M. B.; Ludmány, A.; Baranyi, T.
Several papers provide evidence that the most probable sites of flare onset are the regions of high horizontal magnetic field gradients in solar active regions. Besides the localization of flare-producing areas, this work intends to reveal the characteristic temporal variations in these regions prior to flares. This study uses sunspot data instead…
The Two-dimensional Spatial Distributions of the Globular Clusters and Low-mass X-Ray Binaries of NGC 4649
Zezas, A.; Luo, B.; Fabbiano, G. +5 more
We report significant anisotropies in the projected two-dimensional (2D) spatial distributions of globular clusters (GCs) of the giant Virgo elliptical galaxy NGC 4649 (M60). Similar features are found in the 2D distribution of low-mass X-ray binaries (LMXBs), both associated with GCs and in the stellar field. Deviations from azimuthal symmetry su…
On the Kinematic Separation of Field and Cluster Stars across the Bulge Globular NGC 6528
Prada Moroni, P. G.; Milone, A. P.; Lagioia, E. P. +12 more
We present deep and precise multi-band photometry of the Galactic bulge globular cluster NGC 6528. The current data set includes optical and near-infrared images collected with ACS/WFC, WFC3/UVIS, and WFC3/IR on board the Hubble Space Telescope. The images cover a time interval of almost 10 yr, and we have been able to carry out a proper-motion se…
How Robust are the Size Measurements of High-redshift Compact Galaxies?
Ho, Luis C.; Huang, Song; Peng, Chien Y. +1 more
Massive quiescent galaxies at z ≈ 2 are apparently much more compact than galaxies of comparable mass today. How robust are these size measurements? We perform comprehensive simulations to determine possible biases and uncertainties in fitting single-component light distributions to real galaxies. In particular, we examine the robustness of the me…
Characterization of the Benchmark Binary NLTT 33370
Henning, Thomas; Skemer, Andrew; Leisenring, Jarron +16 more
We confirm the binary nature of the nearby, very low mass (VLM) system NLTT 33370 with adaptive optics imaging and present resolved near-infrared photometry and integrated light optical and near-infrared spectroscopy to characterize the system. VLT-NaCo and LBTI-LMIRCam images show significant orbital motion between 2013 February and 2013 April. O…
Formaldehyde Chemistry in Cometary Ices: On the Prospective Detection of NH2CH2OH, HOCH2OH, and POM by the On-board ROSINA Instrument of the Rosetta Mission
Duvernay, F.; Danger, G.; Theulé, P. +2 more
The thermal reactivity of a water-dominated cometary ice analog containing H2CO and NH3 is investigated by means of Fourier transform infrared spectroscopy, mass spectrometry, and B3LYP calculations. Three products are characterized by these techniques: aminomethanol (NH2CH2OH), methyleneglycol (HOCH
Derivation of an Analytical Approximation of the Spectrum of Spinning Dust Emission
Stevenson, Matthew A.
An analytical function for the spectrum of spinning dust emission is presented. It is derived through the application of careful approximations, with each step tested against numerical calculations. This approach ensures accuracy while providing an intuitive picture of the physics. The final result may be useful for fitting of anomalous microwave …
The Properties of Hα Emission-line Galaxies at Z = 2.24
Kong, Xu; Zheng, Xian Zhong; Gu, Qiu-Sheng +9 more
Using deep narrowband H 2 S1 and K s-band imaging data obtained with CFHT/WIRCam, we identify a sample of 56 Hα emission-line galaxies (ELGs) at z = 2.24 with the 5σ depths of H 2 S1 = 22.8 and K s = 24.8 (AB) over a 383 arcmin2 area in the Extended Chandra Deep Field South. A detailed analysi…
The Gaia Inertial Reference Frame and the Tilting of the Milky Way Disk
Spergel, David N.; Lindegren, Lennart; Perryman, Michael
While the precise relationship between the Milky Way disk and the symmetry planes of the dark matter halo remains somewhat uncertain, a time-varying disk orientation with respect to an inertial reference frame seems probable. Hierarchical structure formation models predict that the dark matter halo is triaxial and tumbles with a characteristic rat…