Search Publications
Hard X-Ray Tail Discovered in the Clocked Burster GS 1826-238
Jourdain, E.; Roques, J. P.; Rodi, J.
The low-mass X-ray binary (LMXB) neutron star (NS) GS 1826-238 was discovered by Ginga in 1988 September. Due to the presence of quasi-periodicity in the type I X-ray burst rate, the source has been a frequent target of X-ray observations for almost 30 years. Though the bursts were too soft to be detected by INTEGRAL/SPI, the persistent emission f…
On More Sensitive Periodogram Statistics
Bélanger, G.
Period searches in event data have traditionally used the Rayleigh statistic, R 2. For X-ray pulsars, the standard has been the Z 2 statistic, which sums over more than one harmonic. For γ-rays, the H-test, which optimizes the number of harmonics to sum, is often used. These periodograms all suffer from the same problem, name…
Prediction of Forbidden Ultraviolet and Visible Emissions in Comet 67P/Churyumov-Gerasimenko
Galand, Marina; Bhardwaj, Anil; Raghuram, Susarla
Remote observation of spectroscopic emissions is a potential tool for the identification and quantification of various species in comets. The CO Cameron band (to trace CO2) and atomic oxygen emissions (to trace H2O and/or CO2, CO) have been used to probe neutral composition in the cometary coma. Using a coupled-che…
An Integrated Model for the Production of X-Ray Time Lags and Quiescent Spectra from Homogeneous and Inhomogeneous Black Hole Accretion Coronae
Becker, Peter A.; Kroon, John J.
Many accreting black holes manifest time lags during outbursts, in which the hard Fourier component typically lags behind the soft component. Despite decades of observations of this phenomenon, the underlying physical explanation for the time lags has remained elusive, although there are suggestions that Compton reverberation plays an important ro…
Evidence for Non-stellar Rest-frame Near-IR Emission Associated with Increased Star Formation in Galaxies at z ~ 1
van Dokkum, Pieter G.; Franx, Marijn; Brammer, Gabriel +5 more
We explore the presence of non-stellar rest-frame near-IR (2-5 µm) emission in galaxies at z ∼ 1. Previous studies identified this excess in relatively small samples and suggested that such non-stellar emission, which could be linked to the 3.3 µm polycyclic aromatic hydrocarbons feature or hot dust emission, is associated with an incr…
On the Nature of the Small-scale Structure in the Cosmic Microwave Background Observed by PLANCK and WMAP
Verschuur, G. L.; Schmelz, J. T.
Small-scale features observed by Wilkinson Microwave Anisotropy Probe (WMAP) and PLANCK in the frequency range of 22-90 GHz show a nearly flat spectrum, which meets with expectations that they originate in the early universe. However, free-free emission from electrons in small angular scale galactic sources that suffer beam dilution very closely m…
Narrow-line X-Ray-selected Galaxies in the Chandra-COSMOS Field. II. Optically Elusive X-Ray AGNs
Civano, F.; Elvis, M.; Watson, M. G. +1 more
In the Chandra-COSMOS (C-COSMOS) survey, we have looked for X-ray-selected active galactic nuclei (AGNs), which are not detected as such in the optical, the so-called elusive AGNs. A previous study based on XMM-Newton and Sloan Digital Sky Survey observations has found a sample of 31 X-ray AGNs optically misclassified as star-forming (SF) galaxies…
Obliquities of Exoplanet Host Stars from Precise Distances and Stellar Angular Diameters
Quinn, Samuel N.; White, Russel J.
The next generation of exoplanet space photometry missions proposed by both NASA and ESA promise to discover small transiting planets around the nearest and brightest main-sequence stars. The physical and rotational properties of these stars, in conjunction with Gaia-precision distances, can be used to determine the inclination of the stellar rota…
On the Retrieval of Mesospheric Winds on Mars and Venus from Ground-based Observations at 10 µm
Lopez-Valverde, M. A.; Sornig, M.; Sonnabend, G. +1 more
A detailed analysis is presented of ground-based observations of atmospheric emissions on Mars and Venus under non-local thermodynamic equilibrium (non-LTE) conditions at high spectral resolution. Our first goal is to comprehend the difficulties behind the derivation of wind speeds from ground-based observations. A second goal is to set a framewor…
The X-Ray Zurich Environmental Study (X-ZENS). II. X-Ray Observations of the Diffuse Intragroup Medium in Galaxy Groups
Schawinski, Kevin; Finoguenov, Alexis; Silverman, John D. +4 more
We present the results of a pilot XMM-Newton and Chandra program aimed at studying the diffuse intragroup medium (IGM) of optically selected nearby groups from the Zurich ENvironmental Study (ZENS) catalog. The groups are in a narrow mass range about {10}13 {M}⊙ , a mass scale at which the interplay between the IGM and the gr…