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Candidate z ∼ 2.5 Lyman Continuum Sources in the GOODS Fields
Barger, A. J.; Cowie, L. L.; Jones, L. H.
We use the wealth of deep archival optical spectroscopy on the GOODS-South field from Keck, the VLT, and other facilities to select candidate high-redshift Lyman continuum (LyC) leakers in the Hubble Deep UV Legacy Survey (HDUV) data set. We select sources at $2.35\lt z\lt 3.05$ , where the HST/WFC3 F275W filter probes only the redshifted LyC. We …
Extinction in the Large Magellanic Cloud Bar around NGC 1854, NGC 1856, and NGC 1858
Milone, Antonino P.; Panagia, Nino; De Marchi, Guido
We report on the extinction properties in the fields around the clusters NGC 1854, NGC 1856, and NGC 1858 in the bar of the Large Magellanic Cloud. The color-magnitude diagrams of the stars in all these regions show an elongated red giant clump that reveals a variable amount of extinction across these fields, ranging from A V ≃ 0.2 to…
M-subdwarf Research. II. Atmospheric Parameters and Kinematics
Qin, Li; Luo, A. -Li; Hou, Wen +12 more
We applied the revised M subdwarf classification criteria discussed in Zhang et al. to Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR7 and combined the result with the M subdwarf sample from Savcheva et al. to construct a new M subdwarf sample for further study. The atmospheric parameters for each object were derived from fi…
Forward Modeling of Simulated Transverse Oscillations in Coronal Loops and the Influence of Background Emission
Van Doorsselaere, Tom; Antolin, Patrick; Li, Bo +1 more
We simulate transverse oscillations in radiatively cooling coronal loops and forward-model their spectroscopic and imaging signatures, paying attention to the influence of background emission. The transverse oscillations are driven at one footpoint by a periodic velocity driver. A standing kink wave is subsequently formed and the loop cross sectio…
The Quasi-biennial-oscillation-type Signals in the Subsurface Flow Fields during Solar Cycles 23 and 24
Howe, Rachel; Inceoglu, Fadil; Loto'aniu, Paul T. M.
We studied the presence and spatiotemporal evolution of quasi-biennial oscillations (QBOs) in the rotation-rate residuals at target depths of 0.90R⊙, 0.95R⊙, and 0.99R⊙ and at low- (0°-30°), mid- (30°-50°), and high-latitudinal (50°-70°) bands. To achieve these objectives we used data from the Michelson Doppler Ima…
Dynamical Evolution of an Active-region Filament Driven by Magnetic Reconnection
Hou, Yijun; Li, Ting; Zhang, Jun +1 more
Studying solar filament dynamical evolutions is an important approach to reveal the driving mechanism of solar eruptions, which seriously impact on the Sun-Earth system and could cause disastrous space weather. To better understand the evolution process of solar filaments, here we investigate an active-region filament by employing observations fro…
SN 2013ai: A Link between Hydrogen-rich and Hydrogen-poor Core-collapse Supernovae
Lyman, J. D.; Kirshner, R. P.; Suntzeff, N. B. +33 more
We present a study of the optical and near-infrared (NIR) spectra of SN 2013ai along with its light curves. These data range from discovery until 380 days after explosion. SN 2013ai is a fast declining Type II supernova (SN II) with an unusually long rise time, 18.9 ± 2.7 days in the V-band, and a bright V-band peak absolute magnitude of -18.7 ± 0…
Multiepoch Optical Images of IRC+10216 Tell about the Central Star and the Adjacent Environment
Ohyama, Youichi; Ueta, Toshiya; Lee, Ho-Gyu +5 more
Six images of IRC+10216 taken by the Hubble Space Telescope at three epochs in 2001, 2011, and 2016 are compared in the rest frame of the central carbon star. An accurate astrometry has been achieved with the help of Gaia Data Release 2. The positions of the carbon star in the individual epochs are determined using its known proper motion, definin…
Can the Fe K-alpha Line Reliably Predict Supernova Remnant Progenitors?
Frank, Kari A.; Burrows, David N.; Dwarkadas, Vikram V. +1 more
The centroid energy of the Fe Kα line has been used to identify the progenitors of supernova remnants (SNRs). These investigations generally considered the energy of the centroid derived from the spectrum of the entire remnant. Here we use XMM-Newton data to investigate the Fe Kα centroid in 6 SNRs: 3C 397, N132D, W49B, DEM L71, 1E 0102.2-7219, an…
The GOGREEN Survey: Evidence of an Excess of Quiescent Disks in Clusters at 1.0
Cooper, M. C.; Muzzin, Adam; Forrest, Ben +21 more
We present the results of the measured shapes of 832 galaxies in 11 galaxy clusters at 1.0 < z < 1.4 from the GOGREEN survey. We measure the axis ratio (q), the ratio of the minor to the major axis, of the cluster galaxies from near-infrared Hubble Space Telescope imaging using Sérsic profile fitting and compare them with a field sample. We …