Search Publications
Mapping the Nuclear Outflow of the Milky Way: Studying the Kinematics and Spatial Extent of the Northern Fermi Bubble
Jenkins, Edward B.; Hernandez, Svea; Savage, Blair D. +7 more
We report new observations from a systematic, spectroscopic, ultraviolet absorption-line survey that maps the spatial and kinematic properties of the high velocity gas in the Galactic Center (GC) region. We examine the hypothesis that this gas traces the biconical nuclear outflow. We use an ultraviolet spectra of 47 background QSOs and halo stars …
Cosmological discordances. II. Hubble constant, Planck and large-scale-structure data sets
Ishak, Mustapha; Lin, Weikang
We examine systematically the (in)consistency between cosmological constraints as obtained from various current data sets of the expansion history, large-scale-structure (LSS), and cosmic microwave background (CMB) temperature and polarization from Planck. We run (dis)concordance tests within each set and across the three sets using a recently int…
Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets
Deming, Drake; Madhusudhan, Nikku; Knutson, Heather +3 more
Transmission spectroscopy provides a window to study exoplanetary atmospheres, but that window is fogged by clouds and hazes. Clouds and haze introduce a degeneracy between the strength of gaseous absorption features and planetary physical parameters such as abundances. One way to break that degeneracy is via statistical studies. We collect all pu…
The Extended IRTF Spectral Library: Expanded Coverage in Metallicity, Temperature, and Surface Gravity
van Dokkum, Pieter; Conroy, Charlie; Mann, Andrew W. +3 more
We present a 0.7-2.5 µm spectral library of 284 stars observed with the medium-resolution infrared spectrograph, SpeX, at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Maunakea, Hawaii. This library extends the metallicity range of the IRTF Cool Star library beyond solar metallicity to -1.7 < [Fe/H] < 0.6. All of the observed st…
Black Hole Growth Is Mainly Linked to Host-galaxy Stellar Mass Rather Than Star Formation Rate
Lehmer, B. D.; Alexander, D. M.; Bauer, F. E. +14 more
We investigate the dependence of black hole accretion rate (BHAR) on host-galaxy star formation rate (SFR) and stellar mass (M *) in the CANDELS/GOODS-South field in the redshift range of 0.5≤slant z< 2.0. Our sample consists of ≈ {{18,000}} galaxies, allowing us to probe galaxies with 0.1{M}⊙ {{yr}}-1≲ {SFR}≲ 1…
Distance and Properties of NGC 4993 as the Host Galaxy of the Gravitational-wave Source GW170817
Lee, Chung-Uk; Kim, Seung-Lee; Im, Myungshin +9 more
Recently, the optical counterpart of the gravitational-wave source GW170817 has been identified in the NGC 4993 galaxy. Together with evidence from observations in electromagnetic waves, the event has been suggested as a result of a merger of two neutron stars (NSs). We analyze the multi-wavelength data to characterize the host galaxy property and…
Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes
Schlieder, Joshua E.; Howell, Steve B.; Fulton, Benjamin J. +12 more
We present results from a Keck/HIRES radial velocity campaign to study four sub-Saturn-sized planets, K2-27b, K2-32b, K2-39b, and K2-108b, with the goal of understanding their masses, orbits, and heavy-element enrichment. The planets have similar sizes ({R}{{P}} = 4.5-5.5 {R}\oplus ), but have dissimilar masses ({M}{{P
High-resolution observations of flare precursors in the low solar atmosphere
Xu, Yan; Cao, Wenda; Liu, Chang +9 more
Solar flares are generally believed to be powered by free magnetic energy stored in the corona1, but the build up of coronal energy alone may be insufficient to trigger the flare to occur2. The flare onset mechanism is a critical but poorly understood problem, insights into which could be gained from small-scale energy releas…
The nature of massive transition galaxies in CANDELS, GAMA and cosmological simulations
Papovich, Casey; Barro, Guillermo; Bell, Eric F. +25 more
We explore observational and theoretical constraints on how galaxies might transition between the 'star-forming main sequence' (SFMS) and varying 'degrees of quiescence' out to z = 3. Our analysis is focused on galaxies with stellar mass M* > 1010 M⊙, and is enabled by GAMA and CANDELS observations, a semi-analy…
Star Formation at z = 2.481 in the Lensed Galaxy SDSS J1110+6459: Star Formation Down to 30 pc Scales
Rigby, Jane R.; Florian, Michael; Whitaker, Katherine E. +7 more
We present measurements of the surface density of star formation, the star-forming clump luminosity function, and the clump size distribution function, for the lensed galaxy SGAS J111020.0+645950.8 at a redshift of z = 2.481. The physical size scales that we probe, radii r = 30-50 pc, are considerably smaller scales than have yet been studied at t…