Search Publications
Nustar observation of the binary system 4U 0114 + 65
Abdallah, Mohammed H.; Samir, Rasha M.; Leahy, Denis A. +1 more
The high-mass X-ray binary system 4U 0114 + 65 was observed by Nustar in October 2019 and by XMM-Newton in August 2015. Here we performed spectral and timing analysis of the Nustar observation and carry out timing analysis on the XMM-Newton data. We measured the spin period of the neutron star from both observations and found a spin-up rate $\dot{…
Relating peak optical luminosity and orbital period of stellar-mass black holes in X-ray binaries
Maccarone, Thomas J.; Blackmon, Victoria A.
We compare the peak optical luminosity with the orbital period for a sample of 22 stellar-mass black hole candidates with good measurements of both quantities. We find that the peak absolute magnitude for the outbursts follows a linear relation with MV, peak = 3.48(± 0.85) - 3.89(± 0.91) logPorb, which corresponds to a $L_V \…
Broad-band X-ray spectral study of nuclear structure in local obscured radio galaxies
Ueda, Yoshihiro; Ricci, Claudio; Ogawa, Shoji +6 more
Radio galaxies are a key population to understand the importance of relativistic jets in active galactic nucleus (AGN) feedback. We present the results of a systematic, broad-band X-ray spectral analysis of hard X-ray selected radio galaxies to investigate their nuclear structures. In this study, we focus on the seven most radio-loud, X-ray obscur…
Physical parameters of stellar population in star formation regions of galaxies
Egorov, O. V.; Gusev, A. S.; Sakhibov, F. +2 more
We present the results of a study of young unresolved stellar groupings (clusters, OB associations, and their complexes) associated with H II regions, based on the coupling of spectroscopic, photometric and H α spectrophotometric observations of star formation regions. Along with our own observations, we use a part of the spectroscopic and H α dat…
The first mm detection of a neutron star high-mass X-ray binary
Díaz Trigo, M.; Degenaar, N.; Sidoli, L. +9 more
Neutron stars accreting from OB supergiants are often divided between persistently and transiently accreting systems, called supergiant X-ray binaries (SgXBs) and supergiant fast X-ray transients (SFXTs). This dichotomy in accretion behaviour is typically attributed to systematic differences in the massive stellar wind, binary orbit, or magnetic f…
X-ray from outflow-cloud interaction and its application in tidal disruption events
Wang, Wei; Chen, Jiashi
Tidal disruption events (TDEs) may occur in supermassive black holes (SMBHs) surrounded by clouds. TDEs can generate ultrafast and large opening-angle outflow with a velocity of ~0.01-0.2 c, which will collide with clouds with time lags depending on outflow velocity and cloud distances. Since the fraction of the outflow energy transferred into clo…
A new method to determine X-ray luminosity functions of AGN and their evolution with redshift
Page, Mat J.; Alqasim, Ahlam
Almost all massive galaxies today are understood to contain supermassive black holes (SMBH) at their centres. SMBHs grew by accreting material from their surroundings, emitting X-rays as they did so. X-ray luminosity functions (XLFs) of active galactic nuclei (AGN) have been extensively studied in order to understand the AGN population's cosmologi…
Abundance analysis of a nitrogen-rich extreme-helium hot subdwarf from the SALT survey
Dorsch, M.; Jeffery, C. S.; Scott, L. J. A. +2 more
We have performed a detailed spectral analysis of the helium-rich hot subdwarf EC 20187-4939, using data obtained in the SALT survey of helium-rich hot subdwarfs. We have measured its effective temperature, surface gravity, and chemical abundances from the spectrum. Its radius has also been determined by fitting the spectral energy distribution us…
Looking ahead to the sky with the Square Kilometre Array: simulating flux densities and resolved radio morphologies of 0 < z < 2.5 star-forming galaxies
Daddi, Emanuele; Franco, Maximilien; Cibinel, Anna +4 more
SKA-MID surveys will be the first in the radio domain to achieve clearly sub-arcsecond resolution at high sensitivity over large areas, opening new science applications for galaxy evolution. To investigate the potential of these surveys, we create simulated SKA-MID images of a ~0.04 deg2 region of GOODS-North, constructed using multi-ba…
Orbital parameters for an ELM white dwarf with a white dwarf companion: LAMOST J033847.06+413424.2
Huang, Xin; Chen, Xuefei; Li, Zhenwei +13 more
Double white dwarf systems are of great astrophysical importance in the field of gravitational wave and Type Ia supernova. While the binary fraction of CO core white dwarf is about a few per cents, the extremely low mass white dwarfs are all thought to be within binary systems. In this work, we report the orbital solution of a double degenerate sy…