Search Publications
A period-dependent spatial scatter of Galactic black hole transients
Maccarone, T. J.; Charles, P. A.; Gandhi, P. +4 more
There remain significant uncertainties in the origin and evolution of black holes in binary systems, in particular regarding their birth sites and the influence of natal kicks. These are long-standing issues, but their debate has been reinvigorated in the era of gravitational wave detections and the improving precision of astrometric measurements.…
An ablating 2.6 M⊕ planet in an eccentric binary from the Dispersed Matter Planet Project
Jenkins, James S.; Anglada-Escudé, Guillem; Díaz, Matías R. +8 more
Earth-mass exoplanets are difficult to detect. The Dispersed Matter Planet Project (DMPP) identifies stars that are likely to host the most detectable low-mass exoplanets. The star DMPP-3 (HD 42936) shows signs of circumstellar absorption, indicative of mass loss from ablating planets. Here, we report the radial velocity discovery of a highly ecce…
The R-Process Alliance: A Very Metal-poor, Extremely r-process-enhanced Star with [Eu/Fe] = + 2.2, and the Class of r-III Stars
Beers, Timothy C.; Placco, Vinicius M.; Hattori, Kohei +8 more
We report the discovery of J1521-3538, a bright (V = 12.2), very metal-poor ([Fe/H] = -2.8) strongly r-process-enhanced field horizontal branch star, based on a high-resolution, high signal-to-noise Magellan/MIKE spectrum. J1521-3538 shows the largest r-process element overabundance in any known r-process-enhanced star, with [Eu/Fe] = +2.2, and it…
Astrometric effects of gravitational wave backgrounds with nonluminal propagation speeds
Gilmore, Gerard; Mihaylov, Deyan P.; Moore, Christopher J. +2 more
A passing gravitational wave causes a deflection in the apparent astrometric positions of distant stars. The effect of the speed of the gravitational wave on this astrometric shift is discussed. A stochastic background of gravitational waves would result in a pattern of astrometric deflections which are correlated on large angular scales. These co…
Sixteen overlooked open clusters in the fourth Galactic quadrant. A combined analysis of UBVI photometry and Gaia DR2 with ASteCA
Moitinho, A.; Carraro, G.; Perren, G. I. +3 more
Aims: This paper has two main objectives: (1) To determine the intrinsic properties of 16 faint and mostly unstudied open clusters in the poorly known sector of the Galaxy at 270° -300° to probe the Milky Way structure in future investigations. (2) To address previously reported systematics in Gaia DR2 parallaxes by comparing the cluster dist…
The Accretion History of AGN: A Newly Defined Population of Cold Quasars
Kartaltepe, Jeyhan S.; Kirkpatrick, Allison; Marchesi, Stefano +15 more
Quasars are the most luminous of active galactic nuclei, and are perhaps responsible for quenching star formation in their hosts. The Stripe 82X catalog covers 31.3 deg2 of the Stripe 82 field, of which the 15.6 deg2 covered with XMM-Newton is also covered by Herschel/SPIRE. We have 2500 X-ray detected sources with multiwavel…
The Magellan/PFS Exoplanet Search: a 55-d period dense Neptune transiting the bright (V = 8.6) star HD 95338
Butler, R. Paul; Kane, Stephen R.; Crane, Jeffrey D. +14 more
We report the detection of a transiting, dense Neptune planet candidate orbiting the bright (V = 8.6) K0.5V star HD 95338. Detection of the 55-d periodic signal comes from the analysis of precision radial velocities from the Planet Finder Spectrograph on the Magellan II Telescope. Follow-up observations with HARPS also confirm the presence of the …
The Population of Galactic Planetary Nebulae: a Study of Distance Scales and Central Stars Based on the Second Gaia Release
Stanghellini, Letizia; Bucciarelli, Beatrice; Lattanzi, Mario G. +1 more
We matched the astrometry of central stars (CSs) of spectroscopically confirmed Galactic planetary nebulae (PNe) with DR2 Gaia parallaxes (p), finding 430 targets in common with p > 0 and $| {\sigma }_{{\rm{p}}}/p| \lt 1$ ∣ σ p / p ∣ < 1 . A catalog of PNe whose CSs have DR2 Gaia parallaxes is presented in Table 1. We compared DR2 parallaxes…
Experimental Phase Function and Degree of Linear Polarization Curves of Millimeter-sized Cosmic Dust Analogs
Sierks, H.; Blum, J.; Fulle, M. +22 more
We present laboratory measurements of the phase functions and degree of linear polarization (DLP) curves of a selection of millimeter-sized cosmic dust analog particles. The set includes particles with similar sizes but diverse internal structure (compact and porous) and absorbing properties. The measured phase functions are found to be in all cas…
TESS observations of southern ultrafast rotating low-mass stars
Ramsay, Gavin; Doyle, Lauren; Doyle, J. Gerry
In our previous study of low-mass stars using TESS, we found a handful that show a periodic modulation on a period <1 d but also displayed no flaring activity. Here we present the results of a systematic search for ultrafast rotators (UFRs) in the Southern ecliptic hemisphere, which were observed in 2-min cadence with TESS. Using data from Gaia…