Search Publications
The mass fraction of AGN and the Fundamental Plane of black hole activity from a large X-ray-selected sample of LINERs
Best, P. N.; Nisbet, D. M.
A sample of 576 X-ray-selected LINERs was constructed by combining data from the 3XMM-DR4 and SDSS-DR7 catalogues. The sample was used to investigate the fraction of galaxies hosting a LINER, finding that the fraction is a strong function of both stellar mass and black hole mass (increasing as {f_LINER ∝ M^{1.6 ± 0.2}_{*}} and {f_LINER ∝ M^{0.6 ± …
ROSETTA lander Philae: Touch-down reconstruction
Roll, Reinhard; Witte, Lars
The landing of the ROSETTA-mission lander Philae on November 12th 2014 on Comet 67 P/Churyumov-Gerasimenko was planned as a descent with passive landing and anchoring by harpoons at touch-down. Actually the lander was not fixed at touch-down to the ground due to failing harpoons. The lander internal damper was actuated at touch-down for 42.6 mm wi…
HST imaging of the dusty filaments and nucleus swirl in NGC4696 at the centre of the Centaurus Cluster
Fabian, A. C.; Reynolds, C. S.; Pinto, C. +14 more
Narrow-band HST imaging has resolved the detailed internal structure of the 10 kpc diameter H α+[N II] emission line nebulosity in NGC4696, the central galaxy in the nearby Centaurus cluster, showing that the dusty, molecular, filaments have a width of about 60 pc. Optical morphology and velocity measurements indicate that the filaments are dragge…
Decimetre-scaled spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +55 more
We present the results of the photometric and spectrophotometric properties of the 67P/Churyumov-Gerasimenko nucleus derived with the Optical, Spectroscopic and Infrared Remote Imaging System instrument during the closest fly-by over the comet, which took place on 2015 February 14 at a distance of ∼6 km from the surface. Several images covering th…
Properties of massive star-forming clumps with infall motions
Zhou, Jian-Jun; Wu, Gang; Esimbek, Jarken +7 more
In this work, we aim to characterize high-mass clumps with infall motions. We selected 327 clumps from the Millimetre Astronomy Legacy Team 90-GHz survey, and identified 100 infall candidates. Combined with the results of He et al., we obtained a sample of 732 high-mass clumps, including 231 massive infall candidates and 501 clumps where infall is…
The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager
Matthews, Brenda C.; Duchêne, Gaspard; Oppenheimer, Rebecca +33 more
Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ∼30-100 AU in both total and polarized H-band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the…
HST-COS Observations of AGNs. III. Spectral Constraints in the Lyman Continuum from Composite COS/G140L Data
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +1 more
The rest-frame ultraviolet (UV) spectra of active galactic nuclei (AGNs) are important diagnostics of both accretion disk physics and their contribution to the metagalactic ionizing UV background. Though the mean AGN spectrum is well characterized with composite spectra at wavelengths greater than 912 Å, the shorter-wavelength extreme-UV (EUV) rem…
Mirror mode structures ahead of dipolarization front near the neutral sheet observed by Cluster
Zhang, T. L.; Nakamura, R.; Baumjohann, W. +4 more
Magnetic compressional structures ahead of a dipolarization front (DF) on 30 August 2002 are investigated by using Cluster data. Our findings are as follows: (1) the structures, observed near the neutral sheet, are mainly compressional and dominant in BZ; (2) they are almost nonpropagating relative to the local ion bulk flow and their l…
Coronal Hole and Solar Global Magnetic Field Evolution in 1976 - 2012
Bilenko, Irina A.; Tavastsherna, Ksenia S.
We study the spatial-temporal evolution of a coronal hole and compare it with that of the solar global magnetic field in Cycles 21 - 23 (1976 - 2012). We also analyze the latitude-longitude distribution dynamics of coronal holes and the regularities in the global magnetic field associated with the solar polar field reversal. Polar and non-polar co…
Vetting Galactic Leavitt Law Calibrators Using Radial Velocities: On the Variability, Binarity, and Possible Parallax Error of 19 Long-period Cepheids
Holl, B.; Mowlavi, N.; Roelens, M. +9 more
We investigate the radial velocity (RV) variability and spectroscopic binarity of 19 Galactic long-period ({P}{puls} ≳ 10 days) classical Cepheid variable stars whose trigonometric parallaxes are being measured using the Hubble Space Telescope and Gaia. Our primary objective is to constrain possible parallax error due to undetected orbi…