Search Publications
Radial Velocities in the Outermost Disk toward the Anticenter
Allende Prieto, C.; López-Corredoira, M.; Sylos Labini, F. +1 more
We measure the mean Galactocentric radial component of the velocity of stars (v R ) in the disk at 8 kpc < R < 28 kpc in the direction of the anticenter. For this, we use the Apache Point Galactic Evolution Experiment. Furthermore, we compare the result with H I maps along the same line of sight. We find an increase in positive (…
PoGO+ polarimetric constraint on the synchrotron jet emission of Cygnus X-1
Takahashi, Hiromitsu; Uchida, Nagomi; Kataoka, Jun +8 more
We report a polarimetric constraint on the hard X-ray synchrotron jet emission from the Cygnus X-1 black hole binary system. The observational data were obtained using the PoGO+ hard X-ray polarimeter in 2016 July, when Cygnus X-1 was in the hard state. We have previously reported that emission from an extended corona with a low polarization fract…
Assessing the Acceptability of Science Operations Concepts and the Level of Mission Enhancement of Capabilities for Human Mars Exploration Extravehicular Activity
Beaton, K. H.; Chappell, S. P.; Abercromby, A. F. J. +7 more
The Biologic Analog Science Associated with Lava Terrains (BASALT) research project is investigating tools, techniques, and strategies for conducting Mars scientific exploration extravehicular activity (EVA). This has been accomplished through three science-driven terrestrial field tests (BASALT-1, BASALT-2, and BASALT-3) during which the iterativ…
Modeling the Protoplanetary Disks of Two Brown Dwarfs in the Taurus Molecular Cloud
Espaillat, Catherine C.; Macías, Enrique; Rilinger, Anneliese M.
Measuring the properties of protoplanetary disks around brown dwarfs (BDs) is central to understanding the formation of BDs and their planetary companions. We present modeling of CFHT Tau 4 and 2M0444, two BDs with protoplanetary disks in the Taurus Molecular Cloud. By combining modeling of the spectral energy distributions and Atacama Large Milli…
The retrograde orbit of the globular cluster FSR1758 revealed with Gaia DR2
Simpson, Jeffrey D.
We report the first radial velocity measurements of the recently identified globular cluster FSR1758. From the two member stars with radial velocities from the Gaia Radial Velocity Spectrograph reported in Gaia DR2, we find FSR1758 has a radial velocity of 227 ± 1 km s^{-1}. We also find potential extra-tidal star lost from the cluster in the surr…
Spectral analysis of the dipping LMXB system XB 1916-053
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
Context. XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and with a Comptonization component with an electron temperature of 9.4 keV and a photon index Γ between 2…
Saturn's Plasmapause: Signature of Magnetospheric Dynamics
Coates, A. J.; Thomsen, M. F.
We explore the paradigm that Saturn's plasmapause marks the boundary between the magnetic flux tubes that have been circulating around the planet for some time, accumulating a dense load of Enceladus-sourced material, and those that have recently undergone tail reconnection, shedding the bulk of the cold plasma and retaining a more tenuous, heated…
Photometry and Spectroscopy of Faint Candidate Spectrophotometric Standard DA White Dwarfs
Rest, Armin; Matheson, Thomas; Points, Sean +14 more
We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equator, and are all fainter than r ∼ 16.5 mag. This network of stars, when established as standards and together with the three Hubble Space Telescope prim…
MCMC Inversion of Stokes Profiles
Sun, Leilei; Xu, Zhi; Li, Hao +1 more
Stokes inversion techniques, based on the analysis of the polarization in spectral lines, are the most powerful tools to obtain the information about the magnetic and thermodynamic quantities in the solar atmosphere. In this paper, we present a Milne-Eddington inversion code based on Bayesian inference, which is implemented with the Markov chain M…
The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413
Done, Chris; Angelakis, Emmanouil; Landt, Hermine +6 more
We present a multifrequency study of PKS J1222+0413 (4C +04.42), currently the highest redshift γ-ray emitting narrow-line Seyfert 1 (γ-NLS1). We assemble a broad spectral energy distribution (SED) including previously unpublished datasets: X-ray data obtained with the NuSTAR and Neil Gehrels Swift observatories; near-infrared, optical, and UV spe…