Search Publications
Cooling of the Crust in the Neutron Star Low-Mass X-Ray Binary MXB 1659-29
Miller, Jon M.; Cackett, Edward M.; Wijnands, Rudy +2 more
In quasi-persistent neutron star transients, long outbursts cause the neutron star crust to be heated out of thermal equilibrium with the rest of the star. During quiescence, the crust then cools back down. Such crustal cooling has been observed in two quasi-persistent sources: KS 1731-260 and MXB 1659-29. Here we present an additional Chandra obs…
Radio-Quiet Fast and Wide Coronal Mass Ejections
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +5 more
We report on the properties of radio-quiet (RQ) and radio-loud (RL) coronal mass ejections (CMEs) that are fast and wide (FW). RQ CMEs lack type II radio bursts in the metric and decameter-hectometric (DH) wavelengths. RL CMEs are associated with metric or DH type II bursts. We found that ~40% of the FW CMEs from 1996 to 2005 were RQ. The RQ CMEs …
Tracing a disk wind in NGC 3516
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +1 more
Context: X-ray spectra of AGN often contain signatures indicative of absorption in multiple layers of gas whose ionization-state and covering fraction may vary with time. It has been unclear to date how much of the observed X-ray spectral and timing behavior in AGN can be attributed to variations in absorption, versus variations in the strengths o…
Masses of Nix and Hydra
Buie, Marc W.; Grundy, William M.; Tholen, David J. +1 more
A four-body orbit solution for the Pluto system yields GM values of 870.3 ± 3.7, 101.4 ± 2.8, 0.039 ± 0.034, and 0.021 ± 0.042 km3 s-2 for Pluto, Charon, Nix, and Hydra, respectively. Assuming a Charon-like density of 1.63 gm cm-3, the implied diameters for Nix and Hydra are 88 and 72 km, leading to visual geometri…
Point spread function tails and the measurements of diffuse stellar halo light around edge-on disc galaxies
de Jong, Roelof S.
Measuring the integrated stellar halo light around galaxies is very challenging. The surface brightness of these haloes is expected to be many magnitudes below dark sky and the central brightness of the galaxy. Here, I show that in some of the recent literature the effect of very extended Point Spread Function (PSF) tails on the measurements of ha…
Properties of the ultraviolet flux of Type Ia supernovae: an analysis with synthetic spectra of SN 2001ep and SN 2001eh
Challis, P.; Kirshner, R. P.; Filippenko, A. V. +7 more
The spectral properties of Type Ia supernovae in the ultraviolet (UV) are investigated using the early-time spectra of SN 2001ep and SN 2001eh obtained using the Hubble Space Telescope. A series of spectral models is computed with a Monte Carlo spectral synthesis code, and the dependence of the UV flux on the elemental abundances and the density g…
Centimetre-wave continuum radiation from the ρ Ophiuchi molecular cloud
Paladini, Roberta; Lim, Tanya; Casassus, Simon +8 more
The ρ Oph molecular cloud is undergoing intermediate-mass star formation. Ultraviolet radiation from its hottest young stars heats and dissociates exposed layers, but does not ionize hydrogen. Only faint radiation from the Rayleigh-Jeans tail of ~10-100 K dust is expected at wavelengths longwards of ~3 mm. Yet cosmic background imager (CBI) observ…
Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies Using X-Ray Emission: Results from the Chandra Deep Fields
Wolf, C.; Lehmer, B. D.; Hornschemeier, A. E. +11 more
We report on the X-ray evolution over the last ≈9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S, respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies, which were identified using rest-fr…
Multiwavelength observations of a giant flare on CN Leonis. I. The chromosphere as seen in the optical spectra
Liefke, C.; Schmitt, J. H. M. M.; Reiners, A. +1 more
Aims: Flares on dM stars contain plasmas at very different temperatures and thus affect a wide wavelength range in the electromagnetic spectrum. While the coronal properties of flares are studied best in X-rays, the chromosphere of the star is observed best in the optical and ultraviolet ranges. Therefore, multiwavelength observations are essentia…
Temperature structure of the intergalactic medium within seven nearby and bright clusters of galaxies observed with XMM-Newton
Bourdin, H.; Mazzotta, P.
Aims:Using a newly developed algorithm, we map, to the highest angular resolution allowed by the data, the temperature structure of the intra-cluster medium (ICM) within a nearly complete X-ray flux limited sample of galaxy clusters in the redshift range between {z}=0.045 and {z}=0.096. Our sample contains seven bright clusters of galaxies observe…