Search Publications
Simultaneous Millimetre-wave and X-ray monitoring of the Seyfert galaxy NGC 7469
Kaspi, Shai; Laor, Ari; Mehdipour, Missagh +6 more
We report on daily monitoring of the Seyfert galaxy NGC 7469, around 95 and 143 GHz, with the IRAM (Institut de Radioastronomie Millimetrique) 30- m radio telescope, and with the Swift X-ray and UV/optical telescopes, over an overlapping period of 45 d. The source was observed on 36 d with IRAM, and the flux density in both mm bands was on average…
The X-ray emissivity of low-density stellar populations
van den Berg, M.; Heinke, C. O.; Cohn, H. N. +17 more
The dynamical production of low-mass X-ray binaries and brighter cataclysmic variables (CVs) in dense globular clusters is well-established. We investigate how the X-ray emissivity of fainter X-ray binaries (principally CVs and coronally active binaries) varies between different environments. We compile calculations (largely from the literature) o…
Impact of the reflection model on the estimate of the properties of accreting black holes
Tripathi, Ashutosh; Bambi, Cosimo; Liu, Honghui
Relativistic reflection features in the X-ray spectra of black hole binaries and active galactic nuclei originate from illumination of the inner part of the accretion disc by a hot corona. In the presence of high quality data and with the correct astrophysical model, X-ray reflection spectroscopy can be quite a powerful tool to probe the strong gr…
A Study of the Blue Straggler Population of the Old Open Cluster Collinder 261
Monaco, L.; Beccari, G.; Villanova, S. +4 more
Blue stragglers (BSs) are stars located in an unexpected region of the color-magnitude diagram (CMD) of a stellar population, as they appear bluer and more luminous than the stars in the turn-off region. They are ubiquitous, since they have been found among Milky Way field stars, in open and globular clusters, and also in other galaxies of the Loc…
A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE). VII. Bridging the cluster-ICM-galaxy evolution at small scales
Andreani, P.; Ferrarese, L.; Buat, V. +20 more
Aims: We measure far-infrared (FIR) emission from tails of stripped dust following the ionised and atomic gas components in galaxies undergoing ram pressure stripping. We study the dust-to-gas relative distribution and mass ratio in the stripped interstellar medium and relate them to those of the intra-cluster medium (ICM), thus linking the c…
Multiwavelength power-spectrum analysis of NGC 5548
Papadakis, I. E.; Dovčiak, M.; Kammoun, E. S. +1 more
NGC 5548 was recently monitored intensively from NIR to X-rays as part of the STORM campaign. Its disc emission was found to lag behind the observed X-rays, while the measured time lag was increasing with wavelength. These results are consistent with the assumption that short-term variability in AGN emission is driven by the X-ray illumination of …
A dynamical and radiation semi-analytical model of pulsar-star colliding winds along the orbit: Application to LS 5039
Molina, E.; Bosch-Ramon, V.
Context. Gamma-ray binaries are systems that emit nonthermal radiation peaking at energies above 1 MeV. One proposed scenario to explain their emission consists of a pulsar orbiting a massive star, with particle acceleration taking place in shocks produced by the interaction of the stellar and pulsar winds.
Aims: We develop a semi-analytical …
OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +31 more
We report the discovery and the analysis of the short ( ${t}_{{\rm{E}}}\lt 5$ days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing Experiment, and the planetary anomaly (at I ∼ 19) was captured by The Korea Microlensing Telescope Network. The event has three surviving planetary model…
CANDELS Meets GSWLC: Evolution of the Relationship between Morphology and Star Formation Since z = 2
Faber, S. M.; Tacchella, Sandro; Salim, Samir +7 more
Galaxy morphology and its evolution over the cosmic epoch hold important clues for understanding the regulation of star formation (SF). However, studying the relationship between morphology and SF has been hindered by the availability of consistent data at different redshifts. Our sample, combining CANDELS (0.8 < z < 2.5) and the GALEX-SDSS-…
Can Subphotospheric Magnetic Reconnection Change the Elemental Composition in the Solar Corona?
Long, David M.; Brooks, David H.; Baker, Deborah +6 more
Within the coronae of stars, abundances of those elements with low first ionization potential (FIP) often differ from their photospheric values. The coronae of the Sun and solar-type stars mostly show enhancements of low-FIP elements (the FIP effect) while more active stars such as M dwarfs have coronae generally characterized by the inverse-FIP e…