Search Publications
On measuring the Galactic dark matter halo with hypervelocity stars
Rossi, E. M.; Marchetti, T.; Contigiani, O.
Hypervelocity stars (HVSs) travel from the Galactic Centre across the dark matter halo of the Milky Way, where they are observed with velocities in excess of the Galactic escape speed. Because of their quasi-radial trajectories, they represent a unique probe of the still poorly constrained dark matter component of the Galactic potential. In this p…
The Methane Diurnal Variation and Microseepage Flux at Gale Crater, Mars as Constrained by the ExoMars Trace Gas Orbiter and Curiosity Observations
Atreya, Sushil K.; Newman, Claire E.; Moores, John E. +8 more
The upper bound of 50 parts per trillion by volume for Mars methane above 5 km established by the ExoMars Trace Gas Orbiter, substantially lower than the 410 parts per trillion by volume average measured overnight by the Curiosity Rover, places a strong constraint on the daytime methane flux at the Gale crater. We propose that these measurements m…
Unexpected Behavior of the Solar Wind Mass Flux During Solar Maxima: Two Peaks at Middle Heliolatitudes
Quémerais, Eric; Koutroumpa, Dimitra; Katushkina, Olga +2 more
In this work we study the temporal and latitudinal variations of the solar wind mass flux at 1 AU derived from SOHO/SWAN data on backscattered solar Lyman-α radiation in 1996 - 2018. Previously Katushkina et al. (J. Geophys. Res.118, 2800, 2013) have shown that the latitudinal profiles of the solar wind mass flux during the solar maximum 2001 - 20…
Evidence for Inside-out Galaxy Growth and Quenching of a z ∼ 2 Compact Galaxy From High-resolution Molecular Gas Imaging
Weiner, Benjamin J.; Bezanson, Rachel; Williams, Christina C. +2 more
We present high spatial resolution imaging of the CO(1-0) line from the Karl G. Jansky Very Large Array of COSMOS 27289, a massive, compact star-forming galaxy (SFG) at z = 2.234. This galaxy was selected because of its structural similarity to z ∼ 2 passive galaxies. Our previous observations showed that it is very gas poor with respect to typica…
A relativistic disc reflection model for 1H0419-577: Multi-epoch spectral analysis with XMM-Newton and NuSTAR
Fabian, Andrew C.; Walton, Dominic J.; Jiang, Jiachen +1 more
We present a detailed analysis of the spectral properties of the Seyfert 1 galaxy 1H0419-577, based on the archival XMM-Newton, NuSTAR, and simultaneous Swift observations taken between 2002 and 2015. All the observations show a broad emission line feature at the iron band. We demonstrate that the broad-band spectral variability at different level…
The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548
Starkey, D. A.; Pott, J. -U.; Peterson, B. M. +16 more
We have recently initiated the first spectroscopic dust reverberation programme on active galactic nuclei in the near-infrared. Spectroscopy enables measurement of dust properties, such as flux, temperature, and covering factor, with higher precision than photometry. In particular, it enables measurement of both luminosity-based dust radii and dus…
New Hot Subdwarf Stars Identified in Gaia DR2 with LAMOST DR5 Spectra. II.
Zhao, Gang; Németh, Péter; Zhao, Jingkun +1 more
Three hundred and eighty eight hot subdwarf stars have been identified by using the Hertzsprung-Russell (HR) diagram built from the second data release of the Gaia mission. By analyzing their observed Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) spectra, we characterized 186 sdB, 73 He-sdOB, 65 sdOB, 45 sdO, 12 He-sdO, and 7 …
Star-density Profiles of Six Old Star Clusters in the Large Magellanic Cloud
Cadelano, Mario; Pallanca, Cristina; Dalessandro, Emanuele +6 more
We used resolved star counts from Hubble Space Telescope (HST) images to determine the center of gravity and the projected density profiles of six old globular clusters (GCs) in the Large Magellanic Cloud (LMC), namely NGC 1466, NGC 1841, NGC 1898, NGC 2210, NGC 2257, and Hodge 11. For each system, the LMC field contribution was properly taken int…
Analysis of Neptune's 2017 bright equatorial storm
de Pater, Imke; Wong, Michael H.; Magnier, Eugene A. +22 more
We report the discovery of a large ( ∼ 8500 km diameter) infrared-bright storm at Neptune's equator in June 2017. We tracked the storm over a period of 7 months with high-cadence infrared snapshot imaging, carried out on 14 nights at the 10 m Keck II telescope and 17 nights at the Shane 120 inch reflector at Lick Observatory. The cloud feature was…
On the different levels of dust attenuation to nebular and stellar light in star-forming galaxies
Yamamura, Issei; Koyama, Yusei; Kodama, Tadayuki +2 more
As a science verification study of the newly released AKARI/FIS Faint Source Catalog ver. 1, this paper discusses the different levels of dust attenuation toward stellar light and nebular emission lines within local star-forming galaxies at 0.02 < z < 0.10. By constructing an updated version of the AKARI-SDSS-GALEX matched galaxy catalog (wi…