Search Publications
X-Ray Reverberation Mapping and Dramatic Variability of Seyfert 1 Galaxy 1H 1934-063
Frederick, Sara; Kara, Erin; Fabian, Andrew +2 more
A fraction of active galactic nuclei (AGN) exhibit dramatic variability, which is observed on timescales down to minutes in the X-ray band. We introduce the case study of 1H 1934-063 (z = 0.0102), a Narrow-line Seyfert 1 among the brightest and most variable AGN ever observed with XMM-Newton. This work includes spectral and temporal analyses of a …
Large catchment area recharges Titan's Ontario Lacus
Barnes, Jason W.; Kirk, Randolph L.; Dhingra, Rajani D. +1 more
We seek to address the question of what processes are at work to fill Ontario Lacus while other, deeper south polar basins remain empty. Our hydrological analysis indicates that Ontario Lacus has a catchment area spanning 5.5% of Titan's surface and a large catchment area to lake surface area ratio. This large catchment area translates into large …
Multi-wavelength campaign on NGC 7469. II. Column densities and variability in the X-ray spectrum
Kriss, G. A.; Arav, N.; Bianchi, S. +16 more
We have investigated the ionic column density variability of the ionized outflows associated with NGC 7469, to estimate their location and power. This could allow a better understanding of galactic feedback of AGNs to their host galaxies. Analysis of seven XMM-Newton grating observations from 2015 is reported. We used an individual-ion spectral fi…
Spectroscopic orbits of nearby solar-type dwarfs - II.
Tokovinin, A.; Gorynya, N. A.
Several nearby solar-type dwarfs with variable radial velocity were monitored to find their spectroscopic orbits. First orbital elements of 15 binaries (HIP 12144, 17895, 27970, 32329, 38636, 39072, 40479, 43004, 73700, 79234, 84696, 92140, 88656, 104514, and 112222) are determined. The previously known orbits of HIP 5276, 21443, 28678, and 41214 …
On the detection of CO and mass-loss of bulge OH/IR stars
Blommaert, J. A. D. L.; Justtanont, K.; Decin, L. +1 more
We report on the successful search for CO (2-1) and (3-2) emission associated with OH/IR stars in the Galactic bulge. We observed a sample of eight extremely red asymptotic giant branch stars with the Atacama Pathfinder EXperiment telescope and detected seven. The sources were selected at a sufficiently high galactic latitude to avoid interference…
Restframe UV-to-optical spectroscopy of APM 08279+5255. BAL classification and black hole mass estimates
Fiore, F.; Vignali, C.; Piconcelli, E. +9 more
We present the analysis of the restframe optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z = 3.911. The spectroscopic data were taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between C III] λ1910 and [O III] λλ4959,5007. We have inv…
Broad absorption line symbiotic stars: highly ionized species in the fast outflow from MWC 560
Sokoloski, J. L.; Knigge, Christian; Lucy, Adrian B.
In symbiotic binaries, jets and disc winds may be integral to the physics of accretion on to white dwarfs from cool giants. The persistent outflow from symbiotic star MWC 560 (≡V694 Mon) is known to manifest as broad absorption lines (BALs), most prominently at the Balmer transitions. We report the detection of high-ionization BALs from C IV, Si I…
SU Lyn: Diagnosing the Boundary Layer with UV and Hard X-Ray Data
Nelson, T.; Mukai, K.; Sokoloski, J. L. +2 more
Symbiotic stars in which the symbiotic phenomenon is powered solely by accretion, often at an average rate that is higher than in cataclysmic variable stars, provide an important opportunity to diagnose boundary layers around disk-accreting white dwarfs. Here, we investigate SU Lyncis (SU Lyn), a recently discovered example of a purely accretion-p…
A study of dust properties in the inner sub-au region of the Herbig Ae star HD 169142 with VLTI/PIONIER
Matter, A.; Weigelt, G.; Ábrahám, P. +3 more
Context. An essential step to understanding protoplanetary evolution is the study of disks that contain gaps or inner holes. The pre-transitional disk around the Herbig star HD 169142 exhibits multi-gap disk structure, differentiated gas and dust distribution, planet candidates, and near-infrared fading in the past decades, which make it a valuabl…
New precise astrometric observations of Nereid in 2012-2017
Cheng, X.; Yan, D.; Qiao, R. C. +4 more
Nereid is one of the most distinctive natural satellites that we know in the Solar system. The orbit of Nereid is highly eccentric and inclined with respect to the equator of its primary, Neptune. Studying Nereid is one of the inspiring ways to acquire better knowledge of the Solar system. Due to its faintness, the ground-based observations of Ner…