Search Publications
Hubble Space Telescope Snapshot Search for Planetary Nebulae in Globular Clusters of the Local Group
Bond, Howard E.
Single stars in ancient globular clusters (GCs) are believed incapable of producing planetary nebulae (PNs), because their post-asymptotic-giant-branch evolutionary timescales are slower than the dissipation timescales for PNs. Nevertheless, four PNs are known in Galactic GCs. Their existence likely requires more exotic evolutionary channels, incl…
X-Ray Emission from the Taffy (VV254) Galaxies and Bridge
Boulanger, F.; Helou, G.; Appleton, P. N. +11 more
We present the first X-ray observations of the Taffy galaxies (UGC 12914/5) with the Chandra observatory and detect soft X-ray emission in the region of the gas-rich, radio-continuum-emitting Taffy bridge. The results are compared to Herschel observations of dust and diffuse [C ii] line-emitting gas. The diffuse component of the Taffy bridge has a…
Pulse-phase dependence of emission lines in the X-ray pulsar 4U 1626-67
Paul, Biswajit; Beri, Aru; Dewangan, Gulab C.
We present results from a pulse-phase-resolved spectroscopy of the complex emission lines around 1 keV in the unique accretion-powered X-ray pulsar 4U 1626-67, using the observation made with XMM-Newton in 2003. In this source, the redshifted and blueshifted emission lines and the linewidths measured earlier with Chandra suggest their accretion-di…
A Spitzer/IRAC characterization of Galactic AGB and RSG stars
Fazio, Giovanni G.; Reiter, Megan; Marengo, Massimo +1 more
We present new Spitzer/InfraRed Array Camera (IRAC) observations of 55 dusty long-period variables (48 asymptotic giant branch, AGB, and 6 red supergiant stars) in the Galaxy that have different chemistry, variability type, and mass-loss rate. O-rich AGB stars (including intrinsic S-type) tend to have redder [3.6]-[8.0] colours than carbon stars f…
Geometric characterization of the Arjuna orbital domain
de la Fuente Marcos, R.; de la Fuente Marcos, C.
Arjuna-type orbits are characterized by being Earth-like, having both low-eccentricity and low-inclination. Objects following these trajectories experience repeated trappings in the 1:1 commensurability with the Earth and can become temporary Trojans, horseshoe librators, quasi-satellites, and even transient natural satellites. Here, we review wha…
Non-detection of post-eclipse changes in Io's Jupiter-facing atmosphere: Evidence for volcanic support?
Tsang, Constantine C. C.; Spencer, John R.; Jessup, Kandis Lea
We present observations of Io's tenuous lower atmosphere on the Jupiter-facing hemisphere at ultraviolet wavelengths, from 2100 to 2250 Å, using the Hubble Space Telescope's Cosmic Origins Spectrometer, during the period immediately after Io emerges from Jupiter eclipse. The density of an atmosphere dominantly controlled by frost sublimation is hi…
Estimation of cold plasma outflow during geomagnetic storms
André, M.; Eriksson, A.; Haaland, S. +11 more
Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shiel…
Herschel Observations of the W3 GMC (II): Clues to the Formation of Clusters of High-mass Stars
Martin, P. G.; Hill, T.; White, G. J. +18 more
The W3 giant molecular cloud is a prime target for investigating the formation of high-mass stars and clusters. This second study of W3 within the HOBYS Key Program provides a comparative analysis of subfields within W3 to further constrain the processes leading to the observed structures and stellar population. Probability density functions (PDFs…
Broad-band spectroscopy of the eclipsing high-mass X-ray binary 4U 1700-37 with Suzaku
Naik, Sachindra; Jaisawal, Gaurava K.
We present the results obtained from broad-band spectroscopy of the high-mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in t…
Practical cosmology with lenses
Eales, S. A.
Surveys with submillimetre telescopes are revealing large numbers of gravitationally lensed high-redshift sources. I describe how, in practice, these lensed systems could be simultaneously used to estimate the values of cosmological parameters, test models for the evolution of the distribution of dark-matter haloes and investigate the properties o…