Search Publications
An Ultramassive, Fast-Spinning White Dwarf in a Peculiar Binary System
Tiengo, A.; Mereghetti, S.; Stella, L. +3 more
White dwarfs typically have masses in a narrow range centered at about 0.6 solar mass (M⊙). Only a few ultramassive white dwarfs (mass > 1.2 M⊙) are known. Those in binary systems are of particular interest, because a small amount of accreted mass could drive them above the Chandrasekhar limit, beyond which they become gra…
Discovery of Gamma-Ray Emission From the Shell-Type Supernova Remnant RCW 86 With Hess
Santangelo, A.; Quirrenbach, A.; Ripken, J. +151 more
The shell-type supernova remnant (SNR) RCW 86, possibly associated with the historical supernova SN 185, with its relatively large size (about 40' in diameter) and the presence of nonthermal X-rays is a promising target for γ-ray observations. The high sensitivity, good angular resolution of a few arcminutes and the large field of view of the High…
Obscured Star Formation in Intermediate-Density Environments: A Spitzer Study of the Abell 901/902 Supercluster
Papovich, Casey; Bell, Eric F.; Gallazzi, Anna +23 more
We explore the amount of obscured star formation as a function of environment in the Abell 901/902 (A901/902) supercluster at z = 0.165 in conjunction with a field sample drawn from the A901 and CDFS fields, imaged with the Hubble Space Telescope as part of the Space Telescope A901/902 Galaxy Evolution Survey and Galaxy Evolution from Morphology a…
Dust-Bounded Ultraluminous Infrared Galaxies: Model Predictions for Infrared Spectroscopic Surveys
Abel, N. P.; van Hoof, P. A. M.; Satyapal, S. +2 more
The observed faintness of infrared fine-structure line emission along with the warm far-infrared (FIR) colors of ultraluminous infrared galaxies (ULIRGs) is a long-standing problem. In this work, we calculate the line and continuum properties of a cloud exposed to an active galactic nucleus (AGN) and starburst spectral energy distribution. We use …
An Energetic AGN Outburst Powered by a Rapidly Spinning Supermassive Black Hole or an Accreting Ultramassive Black Hole
Kirkpatrick, C. C.; McNamara, B. R.; Nulsen, P. E. J. +4 more
Powering the 1062 erg nuclear outburst in the MS0735.6+7421 cluster central galaxy by accretion with a 10% mass-to-energy conversion efficiency implies that its putative supermassive black hole (SMBH) grew by ~6 × 108 M sun over the past 100 Myr. Guided by data at several wavelengths, we place upper limits on the a…
The fraction of Compton-thick sources in an INTEGRAL complete AGN sample
Bird, A. J.; Ubertini, P.; Malizia, A. +3 more
We study the NH distribution in a complete sample of 88 active galactic nuclei (AGN) selected in the 20-40 keV band from INTEGRAL/Imager on Board the Integral Satellite (IBIS) observations. We find that the fraction of absorbed (NH >= 1022cm2) sources is 43 per cent while the Compton thick AGN compris…
The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds
Indriolo, Nick; Fields, Brian D.; McCall, Benjamin J.
Diffuse interstellar clouds show large abundances of H+ 3 which can only be maintained by a high ionization rate of H2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high cosmic-ray flux, and a large amount of energy residing in cosmic rays. In this pa…
The Chemical Abundances of Tycho G in Supernova Remnant 1572
Filippenko, Alexei V.; Foley, Ryan J.; Simon, Joshua D. +3 more
We present an analysis of the chemical abundances of the star Tycho G in the direction of the remnant of supernova (SN) 1572, based on Keck high-resolution optical spectra. The stellar parameters of this star are found to be those of a G-type subgiant with T eff = 5900 ± 100 K, log(g/cms2) = 3.85 ± 0.30 dex, and [Fe/H] = -0.0…
MOIRCS Deep Survey. IV. Evolution of Galaxy Stellar Mass Function Back to z ~ 3
Ouchi, M.; Uchimoto, Y. K.; Yamada, T. +11 more
We use very deep near-infrared (NIR) imaging data obtained in MOIRCS Deep Survey (MODS) to investigate the evolution of the galaxy stellar mass function back to z ~ 3. The MODS data reach J = 24.2, H = 23.1, and K = 23.1 (5σ, Vega magnitude) over 103 arcmin2 (wide) and J = 25.1, H = 23.7, and K = 24.1 over 28 arcmin2 (deep) i…
Excitation of Kink Waves Due to Small-Scale Magnetic Reconnection in the Chromosphere?
He, Jiansen; Tian, Hui; Marsch, Eckart +1 more
The kink wave, which has often been observed in coronal loops, is considered as a possibly important energy source contributing to coronal heating. However, its generation has not yet been observed. Here, we report the first observation of kink-wave excitation caused by magnetic reconnection as inferred from Solar Optical Telescope measurements ma…