Search Publications
Three-dimensional Magnetic Reconnection Triggering an X-class Confined Flare in Active Region 12192
Hou, Yijun; Li, Ting; Yang, Shuhong +1 more
We present an extensive analysis of the X2.0-class confined flare on 2014 October 27 in the great active region, AR 12192, observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The slipping motion of the substructures within the negative-polarity flare ribbon (R1) and continual reconnection-induced flows during …
The Effect of Spots on the Luminosity Spread of the Pleiades
Herczeg, Gregory J.; Guo, Zhen; Gully-Santiago, Michael
Cool spots on the surface of magnetically active stars modulate their observed brightnesses and temperatures, thereby affecting the stellar locus on the H-R diagram. Recent high-precision space-based photometric surveys reveal the rotational modulation from spots on stars in young clusters, including K2 monitoring of the 125 Myr old Pleiades clust…
Models of the Mass-ejection Histories of Pre-planetary Nebulae. II. The Formation of Minkowski’s Butterfly and its Proboscis in M2-9
Frank, Adam; Balick, Bruce; Liu, Baowei +1 more
M2-9, or the “Minkowski’s Butterfly,” is one of the most iconic outflow sources from an evolved star. In this paper we present a hydrodynamic model of M2-9 in which the nebula is formed and shaped by a steady, low-density (“light”), mildly collimated “spray” of gas injected at 200 km s-1 that interacts with a far denser, intrinsically s…
Imaging Spectroscopy of Ionized Gaseous Nebulae around Optically Faint AGNs at Redshift z ∼ 2
Steidel, Charles C.; Law, David R.; Rudie, Gwen C. +3 more
We present Keck/OSIRIS laser guide-star assisted adaptive optics (LGSAO) integral-field spectroscopy of [O III] λ5007 nebular emission from 12 galaxies hosting optically faint ({ \mathcal R } = 20-25 ν {L}ν ∼ {10}44-{10}46 erg s-1) active galactic nuclei (AGNs) at redshift z ∼ 2-3. In combination with de…
Variability of Disk Emission in Pre-main-sequence and Related Stars. IV. Investigating the Structural Changes in the Inner Disk Region of MWC 480
Bayyari, Ammar; Russell, Ray W.; Sitko, Michael L. +8 more
We present five epochs of near-IR observations of the protoplanetary disk around MWC 480 (HD 31648) obtained with the SpeX spectrograph on NASA’s Infrared Telescope Facility between 2007 and 2013, inclusive. Using the measured line fluxes in the Pa β and Br γ lines, we found the mass accretion rates to be (1.26-2.30) × 10-7 M ⊙
The Parallax of the Red Hypergiant VX Sgr with Accurate Tropospheric Delay Calibration
Menten, Karl M.; Reid, Mark J.; Zhang, Bo +3 more
We report astrometric results of VLBI phase-referencing observations of 22 GHz H2O masers emission toward the red hypergiant VX Sgr, one of most massive and luminous red hypergiant stars in our Galaxy, using the Very Long Baseline Array. A background source, J1820-2528, projected 4.°4 from the target VX Sgr, was used as the phase refere…
Comet C/2011 W3 (Lovejoy) between 2 and 10 Solar Radii: Physical Parameters of the Comet and the Corona
Giordano, Silvio; Raymond, J. C.; Downs, Cooper +3 more
Comet C/2011 W3 (Lovejoy) is the first sungrazing comet in many years to survive perihelion passage. We report ultraviolet observations with the Ultraviolet Coronagraph Spectrometer (UVCS) spectrometer aboard the Solar and Heliospheric Observatory satellite at five heights as the comet approached the Sun. The brightest line, Lyα, shows dramatic va…
JVLA 1.5 GHz Continuum Observation of CLASH Clusters. I. Radio Properties of the BCGs
Donahue, Megan; Rosati, Piero; Aravena, Manuel +6 more
We present high-resolution (∼1″), 1.5 GHz continuum observations of the brightest cluster galaxies (BCGs) of 13 CLASH (Cluster Lensing And Supernova survey with Hubble) clusters at 0.18< z< 0.69 with the Karl G. Jansky Very Large Array (JVLA). Radio emission is clearly detected and characterized for 11 BCGs, while for two of them we obtain o…
Constraining Solar Position and Velocity with a nearby Hypervelocity Star
Hattori, Kohei; Castro, Norberto; Valluri, Monica
Gravitational three-body interaction among binary stars and the supermassive black hole at the center of the Milky Way occasionally ejects a hypervelocity star (HVS) with a velocity of ∼ 1000 {km} {{{s}}}-1. Due to the ejection location, such an HVS initially has negligible azimuthal angular momentum {L}z≃ 0 {kpc} {km} {{{s}}…
Don’t Blink: Constraining the Circumstellar Environment of the Interacting Type Ia Supernova 2015cp
Smith, M.; Filippenko, A. V.; Nugent, P. E. +12 more
Despite their cosmological utility, the progenitors of Type Ia supernovae (SNe Ia) are still unknown, with many efforts focused on whether accretion from a nondegenerate companion can grow a carbon-oxygen white dwarf to near the Chandrasekhar mass. The association of SNe Ia resembling SN 1991T (“91T-like”) with circumstellar interaction may be evi…