Search Publications
First Detection of the White Dwarf Cooling Sequence of the Galactic Bulge
Salaris, M.; Anderson, J.; Pietrinferni, A. +13 more
We present Hubble Space Telescope data of the low-reddening Sagittarius window in the Galactic bulge. The Sagittarius Window Eclipsing Extrasolar Planet Search field (~3'× 3'), together with three more Advanced Camera for Surveys and eight Wide-Field Camera 3 fields, were observed in the F606W and F814W filters, approximately every two weeks for 2…
Delivery of Dust Grains from Comet C/2013 A1 (Siding Spring) to Mars
Samarasinha, Nalin H.; Bauer, James M.; Li, Jian-Yang +7 more
Comet C/2013 A1 (Siding Spring) will have a close encounter with Mars on 2014 October 19. We model the dynamical evolution of dust grains from the time of their ejection from the comet nucleus to the close encounter with Mars, and determine the flux at Mars. Constraints on the ejection velocity from Hubble Space Telescope observations indicate tha…
The Panchromatic Hubble Andromeda Treasury. VII. The Steep Mid-ultraviolet to Near-infrared Extinction Curve in the Central 200 pc of the M31 Bulge
Olsen, Knut; Fouesneau, Morgan; Lauer, Tod R. +8 more
We measure the extinction curve in the central 200 pc of M31 at mid-ultraviolet to near-infrared wavelengths (from 1928 Å to 1.5 µm), using Swift/UVOT and Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3)/Advanced Camera for Surveys (ACS) observations in 13 bands. Taking advantage of the high angular resolution of the HST/WFC3 and ACS …
Detection of Coherent Structures in Photospheric Turbulent Flows
Chian, Abraham C. -L.; Aulanier, Guillaume; Schmieder, Brigitte +4 more
We study coherent structures in solar photospheric flows in a plage in the vicinity of the active region AR 10930 using the horizontal velocity data derived from Hinode/Solar Optical Telescope magnetograms. Eulerian and Lagrangian coherent structures (LCSs) are detected by computing the Q-criterion and the finite-time Lyapunov exponents of the vel…
Phase-resolved X-Ray Spectra of Magnetars and the Coronal Outflow Model
Beloborodov, Andrei M.; Hascoët, Romain; den Hartog, Peter R.
We test a model recently proposed for the persistent hard X-ray emission from magnetars. In the model, hard X-rays are produced by a decelerating electron-positron flow in the closed magnetosphere. The flow decelerates as it radiates its energy away via resonant scattering of soft X-rays, then it reaches the top of the magnetic loop and annihilate…
Star Formation and Black Hole Growth at z ~= 4.8
Trakhtenbrot, Benny; Netzer, Hagai; Shemmer, Ohad +2 more
We report Herschel/SPIRE, Spitzer and Wide-field Infrared Survey Explorer observations of 44 z ~= 4.8 optically selected active galactic nuclei (AGNs). This flux-limited sample contains the highest mass black holes (BHs) at this redshift. Ten of the objects were detected by Herschel and five show emission that is not clearly associated with the AG…
Plasma Physical Parameters along Coronal-mass-ejection-driven Shocks. I. Ultraviolet and White-light Observations
Bemporad, A.; Susino, R.; Lapenta, G.
In this work, UV and white-light (WL) coronagraphic data are combined to derive the full set of plasma physical parameters along the front of a shock driven by a coronal mass ejection. Pre-shock plasma density, shock compression ratio, speed, and inclination angle are estimated from WL data, while pre-shock plasma temperature and outflow velocity …
Accurate Spectroscopic Characterization of Oxirane: A Valuable Route to its Identification in Titan's Atmosphere and the Assignment of Unidentified Infrared Bands
Puzzarini, Cristina; Barone, Vincenzo; Biczysko, Malgorzata +1 more
In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on a…
Force-free Field Modeling of Twist and Braiding-induced Magnetic Energy in an Active-region Corona
Wiegelmann, T.; Thalmann, J. K.; Tiwari, S. K.
The theoretical concept that braided magnetic field lines in the solar corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region (AR) corona has only recently been substantiated by high-resolution observations. From the analysis of coronal images obtained with the High Resolution Coronal Imager…
Roche-lobe Overflow Systems Powered by Black Holes in Young Star Clusters: The Importance of Dynamical Exchanges
Zampieri, Luca; Mapelli, Michela
We have run 600 N-body simulations of intermediate-mass (~3500 M ⊙) young star clusters (SCs; with three different metallicities (Z = 0.01, 0.1, and 1 Z ⊙). The simulations include the dependence of stellar properties and stellar winds on metallicity. Massive stellar black holes (MSBHs) with mass >25 M ⊙ are all…