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Detectability of embedded protoplanets from hydrodynamical simulations
Testi, L.; Rosotti, G.; Sanchis, E. +2 more
We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-sized planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts to being transparent to the planet flux in the infrared (IR…
Swift Monitoring of M51: A 38 day Superorbital Period for the Pulsar ULX7 and a New Transient Ultraluminous X-Ray Source
Fürst, Felix; Walton, Dominic J.; Stern, Daniel +6 more
We present the results from a monitoring campaign made with the Neil Gehrels Swift Observatory of the M51 galaxies, which contain several variable ultraluminous X-ray sources (ULXs). The ongoing campaign started in 2018 May, and we report here on ∼1.5 yr of observations. The campaign, which consists of 106 observations, has a typical cadence of 3-…
Mass Functions of Giant Molecular Clouds and Young Star Clusters in Six Nearby Galaxies
Fall, S. Michael; Chandar, Rupali; Mok, Angus
We compare the mass functions of young star clusters (ages ≤ 10 Myr) and giant molecular clouds (GMCs) in six galaxies that cover a large range in mass, metallicity, and star formation rate (LMC, M83, M51, NGC 3627, the Antennae, and NGC 3256). We perform maximum-likelihood fits of the Schechter function, $\psi (M)\,={dN}/{dM}\propto {M}^{\beta }\…
Highly Alfvénic slow solar wind at 0.3 au during a solar minimum: Helios insights for Parker Solar Probe and Solar Orbiter
Matteini, L.; Horbury, T. S.; Bruno, R. +4 more
Alfvénic fluctuations in solar wind are an intrinsic property of fast streams, while slow intervals typically have a very low degree of Alfvénicity, with much more variable parameters. However, sometimes a slow wind can be highly Alfvénic. Here we compare three different regimes of solar wind, in terms of Alfvénic content and spectral properties, …
A Large Population of Obscured AGN in Disguise as Low-luminosity AGN in Chandra Deep Field South
Heckman, Timothy; Vito, Fabio; Chiaberge, Marco +3 more
Population synthesis models of actively accreting supermassive black holes (or active galactic nuclei (AGN)) predict a large fraction that must grow behind dense, obscuring screens of gas and dust. Deep X-ray surveys are thought to have provided the most complete and unbiased samples of AGN, but there is strong observational evidence that a portio…
Elemental Abundances in M31: A Comparative Analysis of Alpha and Iron Element Abundances in the the Outer Disk, Giant Stellar Stream, and Inner Halo of M31
Gilbert, Karoline M.; Wojno, Jennifer; Guhathakurta, Puragra +3 more
We measured [Fe/H] and [α/Fe] using spectral synthesis of low-resolution stellar spectroscopy for 70 individual red-giant-branch stars across four fields spanning the outer disk, Giant Stellar Stream (GSS), and inner halo of M31. Fields at M31-centric projected distances of 23 kpc in the halo, 12 kpc in the halo, 22 kpc in the GSS, and 26 kpc in t…
Intensity interferometry of P Cygni in the H α emission line: towards distance calibration of LBV supergiant stars
Domiciano de Souza, A.; Vakili, F.; Rivet, J. -P. +7 more
We present intensity interferometry of the luminous blue variable P Cyg in the light of its H α emission performed with 1 m-class telescopes. We compare the measured visibility points to synthesized interferometric data based on the CMFGEN physical modelling of a high-resolution spectrum of P Cyg recorded almost simultaneously with our interferome…
Evidence for variability time-scale-dependent UV/X-ray delay in Seyfert 1 AGN NGC 7469
Peterson, Bradley M.; Horne, Keith; Gültekin, Kayhan +5 more
Using a month-long X-ray light curve from RXTE/PCA and 1.5 month-long UV continuum light curves from IUE spectra in 1220-1970 Å, we performed a detailed time-lag study of the Seyfert 1 galaxy NGC 7469. Our cross-correlation analysis confirms previous results showing that the X-rays are delayed relative to the UV continuum at 1315 Šby 3.49 ± 0.22 d…
Exploring the Perturbed Milky Way Disk and the Substructures of the Outer Disk
Xu, Y.; Liu, C.; Tian, H. +7 more
The recent discovery of a spiral feature in the Z - VZ phase plane in the solar neighborhood implies that the galactic disk has been remarkably affected by a dwarf galaxy passing through it some hundreds of millions of years ago. Using 429,500 Large Sky Area Multi-Object Fibre Spectroscopic Telescope K giants stars, we show that the spi…
Probing the Galactic Halo with RR Lyrae Stars. I. The Catalog
Huang, Y.; Chen, B. -Q.; Wang, C. +9 more
We present a catalog of 5290 RR Lyrae stars (RRLs) with metallicities estimated from spectra of the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) and the Sloan Extension for Galactic Understanding and Exploration (SEGUE) surveys. Nearly 70% of them (3642 objects) also have systemic radial velocities measured. Given the pulsa…