Search Publications
Evolution of the disc atmosphere in the X-ray binary MXB 1659-298, during its 2015-17 outburst
Degenaar, N.; Bianchi, S.; Ponti, G. +3 more
We report on the evolution of the X-ray emission of the accreting neutron star (NS) low-mass X-ray binary (LMXB), MXB 1659-298, during its most recent outburst in 2015-17. We detected 60 absorption lines during the soft state (of which 21 at more than 3σ), that disappeared in the hard state (e.g. the Fe XXV and Fe XXVI lines). The absorbing plasma…
On surface brightness and flux calibration for point and compact extended sources in the AKARI Far-IR All-Sky Survey (AFASS) maps
Takita, Satoshi; Ueta, Toshiya; Szczerba, Ryszard +1 more
The AKARI infrared astronomical satellite produced all-sky survey (AFASS) maps in the far-infrared at roughly arcminute spatial resolution, enabling us to investigate the whole sky in the far-infrared for objects having surface brightnesses greater than a few to a couple of dozen MJy sr-1. While the AFASS maps are absolutely calibrated …
An analysis of binary microlensing event OGLE-2015-BLG-0060
Bennett, D. P.; Soszyński, I.; Udalski, A. +79 more
We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all …
Photometry study in period variation and orbital parameter of two W UMa eclipsing binaries: AV Crb and EK Aqr
Han, Xianming L.; Lu, Hong-peng; Zhang, Li-yun +2 more
We report new light curves of two eclipsing binaries of AV Crb and EK Aqr obtained in 2017 and 2018 using Holcomb and SARA telescopes. We obtain the updated ephemeris and find a continuous period decrease (AV Crb) and increase (EK Aqr), respectively. We used the 2015 version Wilson-Devinney method to analyze the light curves and asymmetries. The e…
LAMOST J011939.222-012150.45: The most barium-enhanced CEMP-s turnoff star
Zhao, Gang; Li, Haining; Matsuno, Tadafumi +2 more
We have performed chemical abundance analyses for a newly discovered metal-poor turn-off star (Teff = 6276 K, log g = 3.93, [Fe/H] = -2.93), LAMOST J011939.222-012150.45, based on high-resolution and high signal-to-noise ratio spectra in both optical and near-UV obtained by Subaru. Abundances have been derived for 20 elements, including…
Broadband X-Ray Constraints on the Accreting Black Hole in Quasar 4C 74.26
Yukita, M.; Ptak, A.; LaMassa, S. +2 more
X-ray data for quasar 4C 74.26 have previously been modeled with a broad Fe Kα emission line and reflection continuum originating in the inner part of the accretion disk around the central supermassive black hole (SMBH), i.e., the strong-gravity regime. We modeled broadband X-ray spectra from Suzaku and NuSTAR with MYTORUS, self-consistently accou…
Multiwavelength campaign on Mrk 509. XVI. Continued HST/COS monitoring of the far-ultraviolet spectrum
Kaastra, J. S.; Kriss, G. A.; Arav, N. +10 more
Aims: To elucidate the location, physical conditions, mass outflow rate, and kinetic luminosity of the outflow from the active nucleus of the Seyfert 1 galaxy Mrk 509, we used coordinated UV and X-ray spectral observations in 2012 to follow up our lengthier campaign conducted in 2009.
Methods: We observed Mrk 509 with the Cosmic Origins …
Magnetized Dust Clouds Penetrating the Terrestrial Bow Shock Detected by Multiple Spacecraft
Lai, H. R.; Russell, C. T.; Jia, Y. D. +1 more
Clouds of charged nanometer dust, produced in intra-meteoroid collisions and accelerated by the magnetized solar wind, twist the interplanetary magnetic field as they are accelerated. Depending on the cloud size, minutes to hours-long perturbations are observed by interplanetary spacecraft and have been termed interplanetary field enhancements (IF…
Results of Many-year Photometry of the Herbig Ae Star AB Aur in the Near Infrared
Grinin, V. P.; Shenavrin, V. I.; Baluev, R. V. +1 more
The results of many-year infrared observations of the Herbig AeBe star AB Aur at 1-5 µm (JHKLM bands) are presented. The duration of the photometric series, together with observations published earlier, is about 18 years. The observations demonstrate that, in contrast to the optical, the star is quite active in the studied infrared range. Th…
A method to calculate gravitational accelerations within discrete localized regions in the Milky Way
Kipper, Rain; Tenjes, Peeter; Tempel, Elmo
We present a method to calculate gravitational potential gradients within regions containing few 10s of thousands stars with known phase space coordinates. The central idea of the method is to calculate orbital arcs for each star within a given region for a certain parametrized potential (gravitational acceleration) and to assume that position of …