Search Publications
The Ultraluminous X-Ray Sources Population of the Galaxy NGC 7456
Salvaterra, R.; Haberl, F.; Tiengo, A. +28 more
Ultraluminous X-ray sources (ULXs) are a class of accreting compact objects with X-ray luminosities above 1039 erg s-1. The ULX population counts several hundred objects but only a fraction are well studied. Here we present a detailed analysis of all ULXs hosted in the galaxy NGC 7456. It was observed in X-rays only once in t…
A radiative transfer model for the spiral galaxy M33★
Tuffs, Richard J.; Popescu, Cristina C.; Grootes, Meiert +5 more
We present the first radiative transfer (RT) model of a non-edge-on disc galaxy in which the large-scale geometry of stars and dust is self-consistently derived through the fitting of multiwavelength imaging observations from the ultraviolet to the submm. To this end, we used the axisymmetric RT model of Popescu et al. and a new methodology for de…
How do atomic code uncertainties affect abundance measurements in the intracluster medium?
Gu, Liyi; Mao, Junjie; Kaastra, Jelle S. +6 more
Accurate chemical abundance measurements of X‑ray‑emitting atmospheres pervading massive galaxies, galaxy groups, and clusters provide essential information on the star formation and chemical enrichment histories of these large‑scale structures. Although the collisionally ionized nature of the intracluster medium (ICM) makes these abundance measur…
A More Efficient Search for H2O Megamaser Galaxies: The Power of X-Ray and Mid-infrared Photometry
Chang, Y. -Y.; Cunha, E. da; Matsushita, S. +10 more
We present an investigation of the dependence of H2O maser detection rates and properties on the mid-IR active galactic nucleus (AGN) luminosity, LAGN, and the obscuring column density, NH, based on mid-IR and hard X-ray photometry. Based on spectral energy distribution fitting that allows for decomposition of the …
Geometry of the X-ray source 1H 0707-495
Done, Chris; Mizumoto, Misaki; Szanecki, Michał +3 more
Aims: We investigate the constraints on the size and location of the X-ray source in 1H 0707-495 determined from the shape of the relativistically smeared reflection from the accretion disc.
Methods: We developed a new code to model an extended X-ray source and we applied this code to all archival XMM observations of 1H 0707-495.
Re…
Quasar Sightline and Galaxy Evolution (QSAGE) survey - II. Galaxy overdensities around UV luminous quasars at z = 1-2
Cullen, F.; Bower, R. G.; Tejos, N. +8 more
We demonstrate that the UV brightest quasars at z = 1-2 live in overdense environments. This is based on an analysis of deep Hubble Space Telescope WFC3 G141 grism spectroscopy of the galaxies along the lines-of-sight to UV luminous quasars in the redshift range z = 1-2. This constitutes some of the deepest grism spectroscopy performed by WFC3, wi…
DeGaS-MC: Dense Gas Survey in the Magellanic Clouds. I. An APEX survey of HCO+ and HCN(2-1) toward the LMC and SMC
Immer, K.; Lebouteiller, V.; Madden, S. C. +9 more
Context. Understanding the star-forming processes is key to understanding the evolution of galaxies. Investigating star formation requires precise knowledge of the properties of the dense molecular gas complexes where stars form and a quantification of how they are affected by the physical conditions to which they are exposed. The proximity, low m…
Newly Improved Ionization Corrections for the Neutral Interstellar Medium: Enabling Accurate Abundance Determinations in Star-forming Galaxies throughout the Universe
Hernandez, Svea; Aloisi, Alessandra; James, Bethan L. +4 more
Studies measuring the chemical abundances of the neutral gas in star-forming galaxies (SFGs) require ionization correction factors (ICFs) to accurately measure their metal contents. In the work presented here, we calculate newly improved ICFs for a sample of SFGs. These new corrections include both the contaminating ionized gas along the line of s…
On the Motion of Stars in the Pleiades According to Gaia DR2 Data
Danilov, V. M.; Seleznev, A. F.
—Several parameters of the Pleiades cluster were estimated. We used Gaia DR2 data on the coordinates, proper motions, and radial velocities of stars in regions with radius d° =2.5° and size 60° × 60° around the cluster center. Based on data on stars with magnitudes mG ≤ 18m, we constructed a map and profile of the density, lu…
The High Helium Abundance and Charge States of the Interplanetary CME and Its Material Source on the Sun
Harrison, R. A.; Davies, J. A.; Barnes, D. +5 more
Identifying the source of the material within coronal mass ejections (CMEs) and understanding CME onset mechanisms are fundamental issues in solar and space physics. Parameters relating to plasma composition, such as charge states and He abundance (AHe), may be different for plasmas originating from differing processes or regions on the…