Search Publications
Systematic Non-LTE Study of the -2.6 < [Fe/H] < 0.2 F and G dwarfs in the Solar Neighborhood. I. Stellar Atmosphere Parameters
Zhang, H. -W.; Chen, Y.; Shi, J. -R. +9 more
We present atmospheric parameters for 51 nearby F and G dwarf and subgiant stars uniformly distributed over the -2.60< [{Fe}/{{H}}]< +0.20 metallicity range that is suitable for the Galactic chemical evolution research. Lines of iron in the two ionization stages, Fe I and Fe II, were used to derive a homogeneous set of effective temperatures…
Implications for the Formation of Blue Straggler Stars from HST Ultraviolet Observations of NGC 188
Sills, Alison; Knigge, Christian; Leigh, Nathan +3 more
We present results of a Hubble Space Telescope (HST) far-ultraviolet (FUV) survey searching for white dwarf (WD) companions to blue straggler stars (BSSs) in open cluster NGC 188. The majority of NGC 188 BSSs (15 of 21) are single-lined binaries with properties suggestive of mass-transfer formation via Roche lobe overflow, specifically through an …
The Sizes of Massive Quiescent and Star-forming Galaxies at z ∼ 4 with ZFOURGE and CANDELS
Papovich, Casey; Kacprzak, Glenn G.; Glazebrook, Karl +17 more
We study the rest-frame ultraviolet (UV) sizes of massive (∼ 0.8× {10}11{M}⊙ ) galaxies at 3.4≤slant z\lt 4.2, selected from the FourStar Galaxy Evolution Survey, by fitting single Sérsic profiles to Hubble Space Telescope/WFC3/F160W images from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. Massive quies…
Large Solar Energetic Particle Events Associated with Filament Eruptions Outside of Active Regions
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +4 more
We report on four large filament eruptions (FEs) from solar cycles 23 and 24 that were associated with large solar energetic particle (SEP) events and interplanetary type II radio bursts. The post-eruption arcades corresponded mostly to C-class soft X-ray enhancements, but an M1.0 flare was associated with one event. However, the associated corona…
High-J CO Sleds in Nearby Infrared Bright Galaxies Observed By Herschel/PACS
Lutz, D.; Genzel, R.; Poglitsch, A. +16 more
We report the detection of far-infrared (FIR) CO rotational emission from nearby active galactic nuclei (AGNs) and starburst galaxies, as well as several merging systems and Ultra-Luminous Infrared Galaxies (ULIRGs). Using the Herschel Photodetector Array Camera and Spectrometer (PACS), we have detected transitions in the Jupp = 14-30 r…
A Semi-analytical Line Transfer Model to Interpret the Spectra of Galaxy Outflows
Panagia, N.; Scarlata, C.
We present a semi-analytical line transfer model, (SALT), to study the absorption and re-emission line profiles from expanding galactic envelopes. The envelopes are described as a superposition of shells with density and velocity varying with the distance from the center. We adopt the Sobolev approximation to describe the interaction between the p…
ALMA Resolves the Spiraling Accretion Flow in the Luminous OB Cluster-forming Region G33.92+0.11
Zhang, Qizhou; Liu, Hauyu Baobab; Galván-Madrid, Roberto +4 more
How rapidly collapsing parsec-scale massive molecular clumps feed high-mass stars and how they fragment to form OB clusters have been outstanding questions in the field of star formation. In this work, we report the resolved structures and kinematics of the approximately face-on, rotating massive molecular clump, G33.92+0.11. Our high-resolution A…
Helium Atmospheres on Warm Neptune- and Sub-Neptune-sized Exoplanets and Applications to GJ 436b
Seager, Sara; Hu, Renyu; Yung, Yuk L.
Warm Neptune- and sub-Neptune-sized exoplanets in orbits smaller than Mercury’s are thought to have experienced extensive atmospheric evolution. Here we propose that a potential outcome of this atmospheric evolution is the formation of helium-dominated atmospheres. The hydrodynamic escape rates of Neptune- and sub-Neptune-sized exoplanets are comp…
The Morphologies of Massive Galaxies from z ~ 3—Witnessing the Two Channels of Bulge Growth
Daddi, E.; Huertas-Company, M.; Mei, S. +8 more
We quantify the morphological evolution of z∼ 0 massive galaxies ({M}*/{M}⊙ ∼ {10}11.2+/- 0.3) from z∼ 3 in the 5 CANDELS fields. The progenitors are selected using abundance matching techniques to account for the mass growth. At z\lt 1, the population matches the massive end of the Hubble sequence, with 30% of pur…
Identification of the High-energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
Bogdanov, Slavko; Halpern, Jules P.
We present X-ray, ultraviolet, and optical observations of 1RXS J154439.4-112820, the most probable counterpart of the unassociated Fermi-LAT source 3FGL J1544.6-1125. The optical data reveal rapid variability, which is a feature of accreting systems. The X-rays exhibit large-amplitude variations in the form of fast switching (within ∼10 s) betwee…