Search Publications
Revival of the Magnetar PSR J1622-4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
Tasse, C.; Camilo, F.; Stappers, B. +205 more
New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100× larger than during its dormant state. The X-ray flu…
A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger
Bondi, M.; Lundqvist, P.; Clements, D. L. +33 more
Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg at infrared and radio wavelengths but was not luminous at …
Accretion Disk Reverberation with Hubble Space Telescope Observations of NGC 4593: Evidence for Diffuse Continuum Lags
Horne, Keith; Goad, Michael R.; Korista, Kirk T. +4 more
The Seyfert 1 galaxy NGC 4593 was monitored spectroscopically with the Hubble Space Telescope as part of a reverberation mapping campaign that also included Swift, Kepler, and ground-based photometric monitoring. During 2016 July 12-August 6, we obtained 26 spectra across a nearly continuous wavelength range of ∼1150-10000 Å. These were combined w…
The MOSDEF Survey: A Stellar Mass-SFR-Metallicity Relation Exists at z ∼ 2.3
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +15 more
We investigate the nature of the relation among stellar mass, star formation rate, and gas-phase metallicity (the {M}* -SFR-Z relation) at high redshifts using a sample of 260 star-forming galaxies at z ∼ 2.3 from the MOSDEF survey. We present an analysis of the high-redshift {M}* -SFR-Z relation based on several emission-lin…
Rotation of Low-mass Stars in Upper Scorpius and ρ Ophiuchus with K2
Rebull, L. M.; Stauffer, J. R.; Cody, A. M. +3 more
We present an analysis of K2 light curves (LCs) for candidate members of the young Upper Sco (USco) association (∼8 Myr) and the neighboring ρ Oph embedded cluster (∼1 Myr). We establish ∼1300 stars as probable members, ∼80% of which are periodic. The phased LCs have a variety of shapes which can be attributed to physical causes ranging from stell…
A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster
Romanowsky, Aaron J.; Brodie, Jean P.; Remillard, Ronald A. +13 more
A unique signature for the presence of massive black holes in very dense stellar regions is occasional giant-amplitude outbursts of multi-wavelength radiation from tidal disruption and subsequent accretion of stars that make a close approach to the black holes1. Previous strong tidal disruption event (TDE) candidates were all associated…
Apocenter Pile-up: Origin of the Stellar Halo Density Break
Belokurov, Vasily; Koposov, Sergey E.; Deason, Alis J. +1 more
We measure the orbital properties of halo stars using seven-dimensional information provided by Gaia and the Sloan Digital Sky Survey. A metal-rich population of stars, present in both local main sequence stars and more distant blue horizontal branch stars, have very radial orbits (eccentricity ∼0.9) and apocenters that coincide with the stellar h…
Isochrone ages for ∼3 million stars with the second Gaia data release
Sanders, Jason L.; Das, Payel
We present a catalogue of distances, masses, and ages for ∼3 million stars in the second Gaia data release with spectroscopic parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE, and SEGUE. We use a Bayesian framework to characterize the probability density functions of distance, mass, and age using pho…
An Optical Transmission Spectrum for the Ultra-hot Jupiter WASP-121b Measured with the Hubble Space Telescope
Nikolov, Nikolay; Drummond, Benjamin; Sing, David K. +24 more
We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. Across the 0.47-1 µ {{m}} wavelength range, the data imply an atmospheric opacity comparable to—and in some spectroscopic channels exceeding—that previously measured…
Scaling Relations Associated with Millimeter Continuum Sizes in Protoplanetary Disks
Wilner, David J.; Andrews, Sean M.; Ansdell, Megan +3 more
We present a combined, homogenized analysis of archival Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations of the spatially resolved 340 GHz (870 µm) continuum emission from 105 nearby protoplanetary disks. Building on the previous SMA survey, we infer surface brightness profiles using a simple mod…