Search Publications
Testing MOND using the dynamics of nearby stellar streams
Helmi, Amina; Koop, Orlin
Context. The stellar halo of the Milky Way is built up at least in part from debris from past mergers. The stars from these merger events define substructures in phase space, for example in the form of streams, which are groups of stars that move on similar trajectories. The nearby Helmi streams discovered more than two decades ago are a well-know…
Radio and gamma-ray timing of TRAPUM L-band Fermi pulsar survey discoveries
Ransom, S. M.; Possenti, A.; Kramer, M. +18 more
This paper presents the results of a joint radio and gamma-ray timing campaign on the nine millisecond pulsars (MSPs) discovered as part of the L-band targeted survey of Fermi-LAT sources performed in the context of the Transients and Pulsars with MeerKAT (TRAPUM) Large Survey Project. Out of these pulsars, eight are members of binary systems; of …
Uncovering an Excess of X-Ray Point Sources in the Halos of Virgo Late-type Galaxies
Li, Zhiyuan; Hou, Meicun; Hu, Zhensong
We present a systematic search for extraplanar X-ray point sources around 19 late-type, highly inclined disk galaxies residing in the Virgo cluster, based on archival Chandra observations reaching a source detection sensitivity of L(0.5–8 keV) ∼ 1038 erg s‑1. Based on the cumulative source surface density distribution as a fu…
AGN feeding along a one-armed spiral in NGC 4593: A study using ALMA CO(2–1) observations
Andreani, P.; Hatziminaoglou, E.; Spinoglio, L. +9 more
Context. We investigate active galactic nuclei (AGN) feeding through the molecular gas (CO(2‑1) emission) properties of the local Seyfert 1 galaxy NGC 4593, using Atacama Large Millimeter Array (ALMA) observations and other multi-wavelength data. Aims. Our study aims to understand the interplay between the AGN and the interstellar medium (ISM) in …
Water Ice Resources on the Shallow Subsurface of Mars: Indications to Rover-Mounted Radar Observation
Orosei, Roberto; Zheng, Naihuan; Ding, Chunyu +1 more
The planet Mars is the most probable among the terrestrial planets in our solar system to support human settlement or colonization in the future. The detection of water ice or liquid water on the shallow subsurface of Mars is a crucial scientific objective for both the Chinese Tianwen-1 and United States Mars 2020 missions, which were launched in …
The variability structure function of the highest luminosity quasars on short time-scales
Tang, Ji-Jia; Wolf, Christian; Tonry, John
The stochastic photometric variability of quasars is known to follow a random-walk phenomenology on emission time-scales of months to years. Some high-cadence rest-frame optical monitoring in the past has hinted at a suppression of variability amplitudes on shorter time-scales of a few days or weeks, opening the question of what drives the suppres…
Performance evaluation of pansharpening for planetary exploration: A case study on the implementation of TGO CaSSIS with MRO HiRISE
Cremonese, G.; Thomas, N.; Re, C. +3 more
The present study analyses the potential of pansharpening algorithms for planetary exploration studies, testing their performance with the 4-band images from the Colour and Stereo Surface Imaging System (CaSSIS) aboard the Exomars 2016 Trace Grace Orbiter (TGO) using HiRISE images from the Mars Reconnaissance Orbiter (MRO) mission as the base. Due…
The Accelerating Decline of the Mass Transfer Rate in the Recurrent Nova T Pyxidis
Williams, Robert E.; Sion, Edward M.; Godon, Patrick +3 more
The recurrent nova T Pyxidis (T Pyx) has erupted six times since 1890, with its last outburst in 2011, and the relatively short recurrence time between classical nova explosions indicates that T Pyx must have a massive white dwarf (WD) accreting at a high rate. It is believed that, since its outburst in 1890, the mass transfer rate in T Pyx was ve…
Searching for pairs of actively accreting supermassive black holes in the Gaia FPR GravLens catalog
Galluccio, L.; Slezak, E.; Mahé, C.
Observational data on dual supermassive black holes (SMBHs) are scarce, even though they should be common according to the current hierarchical formation model for galaxies. We present hereby a method to detect such dual systems, involving an already known quasar, as two luminosity peaks with angular separations smaller than one arcsecond (1″). It…
Unsteady Dungey cycle from the point of view of Stokes' theorem
Semenov, Vladimir S.; Kubyshkin, Igor V.; Tsyganenko, Nikolai A. +3 more
The Dungey cycle is considered from the formation of a magnetic barrier and necessary for dayside reconnection conditions till the electric field generation around the Birkeland current loop and magnetic flux circulation balance. Data-based modeling of the magnetosheath magnetic field makes it possible to quantitatively assess the main factors tha…