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Cataclysmic variable stars (CVs) are close binary systems consisting of a white dwarf (primary) that is accreting matter from a low-mass companion star (secondary). From time to time such systems undergo large-amplitude brightenings. The…

NSV 1907, formerly listed as an irregular variable in variability catalogues, was classified as an Algol-type eclipsing binary in the Catalina Surveys Periodic Variable Star Catalogue. We have identified NSV 1907 as an ultraviolet (UV)…

Based on published sources, we have created a kinematic database on 220 massive (>10 solar masses) young Galactic star systems located within <3 kpc of the Sun. Out of them, approximately 100 objects are spectroscopic binary and multiple…

星系天体物理 · 物理学 2013-07-08 V. V. Bobylev , A. T. Bajkova

The NSF's Karl G. Jansky Very Large Array (VLA) is used to observe 122 magnetic cataclysmic variables (MCVs) during three observing semesters (13B, 15A, and 18A). We report radio detections of 33 stars with fluxes in the range 6--8031 uJy.…

太阳与恒星天体物理 · 物理学 2020-06-16 Paul Barrett , Christopher Dieck , Anthony J. Beasley , Paul A Mason , Kulinder P. Singh

We consider here the class of compact, isolated, high-velocity HI clouds, CHVCs, which are sharply bounded in angular extent down to a limiting column density of 1.5x10^18 cm^-2. We describe our automated search algorithm and it's…

天体物理学 · 物理学 2007-05-23 W. B. Burton , R. Braun , V. de Heij

During a visual search through the Kepler main-field lightcurves, we have discovered a cataclysmic variable (CV) that experienced only a single 4-day long outburst over four years, rising to three times the quiescent flux. During the four…

We report on optical spectroscopic and photometric follow-up observations of the eROSITA discovered transient SRGt 062340.2-265751 and show that it displays the characteristics of a nova-like cataclysmic variable (CV), with possible…

We study cosmic variance in deep high redshift surveys and its influence on the determination of the luminosity function for high redshift galaxies. For several survey geometries relevant for HST and JWST instruments, we characterize the…

天体物理学 · 物理学 2020-07-28 M. Trenti , M. Stiavelli

This paper studies the connection between the relativistic number density of galaxies down the past light cone in a Friedmann-Lemaitre-Robertson-Walker spacetime with non-vanishing cosmological constant and the galaxy luminosity function…

宇宙学与河外天体物理 · 物理学 2012-03-05 Alvaro S. Iribarrem , Amanda R. Lopes , Marcelo B. Ribeiro , William R. Stoeger

We have used HST/FOS to study faint UV stars in the core of the nearby globular cluster NGC 6397. We confirm the presence of a 4th cataclysmic variable (CV) in NGC 6397 (CV 4), and we use the photometry of Cool et al. (1998) to present…

The color-magnitude diagram of the lower main sequence, as measured from a volume-limited sample of nearby stars, shows an abrupt downward jump between Mv = 12 and 13. This jump indicates that the observed mass-radius relationship steepens…

天体物理学 · 物理学 2009-10-30 J. Christopher Clemens , I. Neill Reid , John E. Gizis , M. Sean O'Brien

In its first two years of operation, the James Webb Space Telescope has enabled the discovery of a surprising number of UV-bright galaxies at $z\sim10-14$. Their number density is still relatively uncertain, due to cosmic variance effects,…

We investigate the kinematics of red clump stars in the Solar Neighbourhood by combining data from TGAS and RAVE to constrain the local dark matter density. After calibrating the absolute magnitude of red clump stars, we characterize their…

星系天体物理 · 物理学 2018-07-25 Jorrit H. J. Hagen , Amina Helmi

(Abridged) We present high-speed, three-colour photometry of seven short period (Porb <= 95 mins) eclipsing CVs from the Sloan Digital Sky Survey. We determine the system parameters via a parametrized model of the eclipse fitted to the…

We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using Halpha images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric Halpha Survey of the…

高能天体物理现象 · 物理学 2015-05-25 D. I. Sahman , V. S. Dhillon , C. Knigge , T. R. Marsh

We present a systematic survey for mass-transferring and recently-detached cataclysmic variables (CVs) with evolved secondaries, which are progenitors of extremely low-mass white dwarfs (ELM WDs), AM CVn systems, and detached ultracompact…

太阳与恒星天体物理 · 物理学 2021-12-01 Kareem El-Badry , Hans-Walter Rix , Eliot Quataert , Thomas Kupfer , Ken J. Shen

We present a new approach for quantifying the abundance of galaxy clusters and constraining cosmological parameters using dynamical measurements. In the standard method, galaxy line-of-sight (LOS) velocities, $v$, or velocity dispersions…

宇宙学与河外天体物理 · 物理学 2017-01-25 M. Ntampaka , H. Trac , J. Cisewski , L. C. Price

JWST has enabled the detection of galaxies in the earliest stages of cosmic history. We compare the ultraviolet luminosity functions (UVLFs) at redshifts $z=7-15$ predicted by the new cosmological hydrodynamics simulations, COLIBRE with…

We report the first results from a new search for cataclysmic variables (CVs) using a combined X-ray (ROSAT) / infrared (2MASS) target selection that discriminates against background AGN. Identification spectra were obtained at the Isaac…

I conducted photometric observations of the cataclysmic variable LAMOST J035913.61+405035.0 and discovered previously unknown eclipses. During these observations, I recorded 14 eclipses over two groups of nights separated by 13 months. I…

太阳与恒星天体物理 · 物理学 2024-11-14 V. P. Kozhevnikov