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A multimission catalogue of ultraluminous X-ray source candidates
Earnshaw, H. P.; Roberts, T. P.; Mateos, S. +4 more
We present a new, multimission catalogue of ultraluminous X-ray source (ULX) candidates, based on recent data releases from each of the XMM-Newton, Swift, and Chandra observatories (the 4XMM-DR10, 2SXPS, and CSC2 catalogues, respectively). This has been compiled by cross-correlating each of these X-ray archives with a large sample of galaxies prim…
Do quasar X-ray and UV flux measurements provide a useful test of cosmological models?
Khadka, Narayan; Ratra, Bharat
The recent compilation of quasar (QSO) X-ray and ultraviolet (UV) flux measurements include QSOs that appear to not be standardizable via the X-ray luminosity and UV luminosity (LX-LUV) relation and so should not be used to constrain cosmological model parameters. Here, we show that the largest of seven sub-samples in this co…
All-purpose, all-sky photometric redshifts for the Legacy Imaging Surveys Data Release 8
Duncan, Kenneth J.
In this paper, we present photometric redshift (photo-z) estimates for the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, currently the most sensitive optical survey covering the majority of the extragalactic sky. Our photo-z methodology is based on a machine-learning approach, using sparse Gaussian processes augmented with Ga…
A black hole detected in the young massive LMC cluster NGC 1850
Dreizler, S.; Da Costa, G. S.; Cabrera-Ziri, I. +8 more
We report on the detection of a black hole (NGC 1850 BH1) in the ~100-Myr-old massive cluster NGC 1850 in the Large Magellanic Cloud. It is in a binary system with a main-sequence turn-off star (4.9 ± 0.4 M⊙), which is starting to fill its Roche lobe and is becoming distorted. Using 17 epochs of Very Large Telescope/Multi-Unit Spectrosc…
NGC 1850 BH1 is another stripped-star binary masquerading as a black hole
El-Badry, Kareem; Burdge, Kevin B.
We show that the radial velocity variable star in the black hole (BH) candidate NGC 1850 BH1 cannot be a normal ${\approx}5\hbox{-}{\rm M}_{\odot }$ subgiant, as was proposed, but is an overluminous stripped-envelope star with mass ≈1 M⊙. The result follows directly from the star's observed radius and the orbital period-density relation…
Exploring the physical properties of lensed star-forming clumps at 2 ≲ z ≲ 6
Zanella, A.; Castellano, M.; Grillo, C. +12 more
We study the physical properties (size, stellar mass, luminosity, and star formation rate) and scaling relations for a sample of 166 star-forming clumps with redshift z ~ 2-6.2. They are magnified by the Hubble Frontier Field galaxy cluster MACS J0416 and have robust lensing magnification (2 ≲ µ ≲ 82) computed by using our high-precision len…
Strong Lyman-α emission in an overdense region at z = 6.8: a very large (R 3 physical Mpc) ionized bubble in COSMOS?
Stark, Daniel P.; Endsley, Ryan
Our understanding of reionization has advanced considerably over the past decade, with several results now demonstrating that the intergalactic medium transitioned from substantially neutral at z = 7 to largely reionized at z = 6. However, little remains known about the sizes of ionized bubbles at z ≳ 7 as well as the galaxy overdensities which dr…
Astrometric identification of nearby binary stars - I. Predicted astrometric signals
Belokurov, Vasily; Evans, N. Wyn; Penoyre, Zephyr
We examine the capacity to identify binary systems from astrometric errors and deviations alone. Until the release of the fourth Gaia data release, we lack the full astrometric time-series that the satellite records, but as we show can still infer the presence of binaries from the best-fitting models, and their error, already available. We generat…
The pattern speed of the Milky Way bar/bulge from VIRAC and Gaia
Gerhard, Ortwin; Clarke, Jonathan P.
We compare distance resolved, absolute proper motions in the Milky Way bar/bulge region to a grid of made-to-measure dynamical models with well-defined pattern speeds. The data are obtained by combining the relative VVV InfraRed Astrometric Catalogue (VIRAC) v1 proper motions with the Gaia Data Release 2 absolute reference frame. We undertake a co…
Astrometric identification of nearby binary stars - II. Astrometric binaries in the Gaia Catalogue of Nearby Stars
Belokurov, Vasily; Evans, N. Wyn; Penoyre, Zephyr
We examine the capacity to identify binary systems from astrometric deviations alone. We apply our analysis to the Gaia eDR3 and DR2 data, specifically the Gaia Catalogue of Nearby Stars. We show we must renormalize (R)UWE over the local volume to avoid biasing local observations, giving a local unit weight error (LUWE). We use the simple criterio…