Search Publications
Binarity and Accretion in AGB Stars: HST/STIS Observations of UV Flickering in Y Gem
Sahai, R.; Sánchez Contreras, C.; Sanz-Forcada, J. +3 more
Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to search for hot binary companions to cool AGB stars using the GALEX archive, we discovered a late-M star, Y Gem, to be a source of strong and variable UV and X…
Distance, Energy, and Variability of Quasar Outflows: Two HST/COS Epochs of LBQS 1206+1052
Xu, Xinfeng; Kriss, Gerard A.; Arav, Nahum +4 more
We analyze new HST/COS spectra for two quasar absorption outflows seen in the quasi-stellar object LBQS 1206+1052. These data cover, for the first time, absorption troughs from S IV, Si II, and P V. From the ratio of the S IV* to S IV column densities, we measure the electron number density of the higher-velocity (-1400 km s-1, v1400) o…
Pillars of Creation among Destruction: Star Formation in Molecular Clouds near R136 in 30 Doradus
Guzmán, Viviana V.; Elmegreen, Bruce G.; Zinnecker, Hans +3 more
We present new sensitive CO(2-1) observations of the 30 Doradus region in the Large Magellanic Cloud. We identify a chain of three newly discovered molecular clouds that we name KN1, KN2, and KN3 lying within 2-14 pc in projection from the young massive cluster R136 in 30 Doradus. Excited H2 2.12 µm emission is spatially coinciden…
Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-variable Horizontal-branch Stars. III. M55 and NGC 6362
VandenBerg, Don A.; Denissenkov, P. A.
M55 (NGC 6809) and NGC 6362 are among the few globular clusters for which masses and radii have been derived to high precision for member binary stars. They also contain RR Lyrae variables, which, together with their non-variable horizontal-branch (HB) populations, provide tight constraints on the cluster reddenings and distance moduli through fit…
Statistical Relation between Solar Flares and Coronal Mass Ejections with Respect to Sigmoidal Structures in Active Regions
Akiyama, Sachiko; Yashiro, Seiji; Shimizu, Toshifumi +3 more
Statistical dependences among features of coronal mass ejections (CMEs), solar flares, and sigmoidal structures in soft-X-ray images were investigated. We applied analysis methods to all the features in the same way in order to investigate the reproducibility of the correlations among them, which may be found from previous statistical studies. Sam…
ZFIRE: 3D Modeling of Rotation, Dispersion, and Angular Momentum of Star-forming Galaxies at z ∼ 2
Kewley, Lisa J.; Kacprzak, Glenn G.; Glazebrook, Karl +10 more
We perform a kinematic and morphological analysis of 44 star-forming galaxies at z ∼ 2 in the COSMOS legacy field using near-infrared spectroscopy from Keck/MOSFIRE and F160W imaging from CANDELS/3D-HST as part of the ZFIRE survey. Our sample consists of cluster and field galaxies from 2.0 < z < 2.5 with K-band multi-object slit spectroscopi…
Molecular Cloud Structures and Massive Star Formation in N159
Nayak, O.; Meixner, M.; Fukui, Y. +5 more
The N159 star-forming region is one of the most massive giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC). We show the 12CO, 13CO, CS molecular gas lines observed with ALMA in N159 west (N159W) and N159 east (N159E). We relate the structure of the gas clumps to the properties of 24 massive young stellar object…
A Deep Near-infrared [Fe II]+[Si I] Emission Line Image of the Supernova Remnant Cassiopeia A
Koo, Bon-Chul; Lee, Jae-Joon; Moon, Dae-Sik +4 more
We present a long-exposure (∼10 hr), narrowband image of the supernova (SN) remnant Cassiopeia A (Cas A) centered at 1.644 µm emission. The passband contains [Fe II] 1.644 µm and [Si I] 1.645 µm lines, and our “deep [Fe II]+[Si I] image” provides an unprecedented panoramic view of Cas A, showing both shocked and unshocked SN ejec…
The Extremely Luminous Quasar Survey in the Sloan Digital Sky Survey Footprint. II. The North Galactic Cap Sample
Fan, Xiaohui; McGreer, Ian D.; Huang, Yun-Hsin +10 more
We present the North Galactic Cap sample of the Extremely Luminous Quasar Survey (ELQS-N), which targets quasars with M 1450 < -27 at 2.8 ≤ z < 5 in an area of ∼7600 deg2 of the Sloan Digital Sky Survey (SDSS) footprint with 90° < R.A. < 270°. Based on a near-infrared/infrared JKW2 color cut, the ELQS selection ef…
Extremely Dense Cores Associated with Chandra Sources in Ophiuchus A: Forming Brown Dwarfs Unveiled?
Tamura, Yoichi; Di Francesco, James; Friesen, Rachel +15 more
On the basis of various data such as ALMA, JVLA, Chandra, Herschel, and Spitzer, we confirmed that two protostellar candidates in Oph A are bona fide protostars or proto-brown dwarfs (proto-BDs) in extremely early evolutionary stages. Both objects are barely visible across infrared (IR; i.e., near-IR to far-IR) bands. The physical nature of the co…