Search Publications
The Nucleus of the Planetary Nebula EGB 6 as a Post-Mira Binary
Bond, Howard E.; Munari, Ulisse; Ciardullo, Robin +3 more
EGB 6 is a faint, large, ancient planetary nebula (PN). Its central star, a hot DAOZ white dwarf (WD), is a prototype of a rare class of PN nuclei associated with dense, compact emission-line knots. The central star also shows excess fluxes in both the near-infrared (NIR) and mid-infrared (MIR). In a 2013 paper, we used Hubble Space Telescope (HST…
Millihertz Quasi-periodic Oscillations in 4U 1636-536: Putting Possible Constraints on the Neutron Star Size
Stiele, H.; Yu, W.; Kong, A. K. H.
Based on previous studies of quasi-periodic oscillations (QPOs) in neutron star (NS) low-mass X-ray binaries, mHz QPOs are believed to be related to “marginally stable” burning on the NS surface. Our study of phase-resolved energy spectra of these oscillations in 4U 1636-53 shows that the oscillations are not caused by variations in the blackbody …
Constraining the Solar Coronal Magnetic Field Strength using Split-band Type II Radio Burst Observations
Ramesh, R.; Kathiravan, C.; Hariharan, K. +2 more
We report on low-frequency radio (85-35 MHz) spectral observations of four different type II radio bursts, which exhibited fundamental-harmonic emission and split-band structure. Each of the bursts was found to be closely associated with a whitelight coronal mass ejection (CME) close to the Sun. We estimated the coronal magnetic field strength fro…
Dust and Polycyclic Aromatic Hydrocarbon in the Pre-transitional Disk around HD 169142
Seok, Ji Yeon; Li, Aigen
The pre-transitional disk around the Herbig Ae star HD 169142 shows a complex structure of possible ongoing planet formation in dust thermal emission from the near-infrared (IR) to millimeter wavelength range. Also, a distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 µ {{m}}, commonly attributed to polycyclic arom…
The Off-centered Seyfert-like Compact Emission in the Nuclear Region of NGC 3621
Steiner, J. E.; Menezes, R. B.; da Silva, Patrícia
We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.″14 ± 0.″08 (70.1 ± 2.6 pc) from the stellar nucleus. Only diffuse…
The Collapse of the Wien Tail in the Coldest Brown Dwarf? Hubble Space Telescope Near-infrared Photometry of WISE J085510.83-071442.5
Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +1 more
We present Hubble Space Telescope (HST) near-infrared photometry of the coldest known brown dwarf, WISE J085510.83-071442.5 (WISE 0855-0714). WISE 0855-0714 was observed with the Wide Field Camera 3 (WFC3) on board HST using the F105W, F125W, and F160W filters, which approximate the Y, J, and H near-infrared bands. WISE 0855-0714 is undetected at …
X-Ray Spectra of the High-mass X-Ray Binary 4U 1700-37 Using BeppoSAX, Suzaku, and RXTE Observations
Titarchuk, Lev; Seifina, Elena; Shaposhnikov, Nikolai
We present an X-ray spectral analysis of the high-mass binary 4U 1700-37 during its hard-soft state evolution. We use BeppoSAX, Suzaku, and Rossi X-ray Timing Explorer observations for this investigation. We argue that the X-ray broadband spectra during all of the spectral states can be adequately reproduced by a model consisting of a low-temperat…
Spatially Resolved Spectroscopy of Submillimeter Galaxies at z ≃ 2
Casey, Caitlin M.; Treister, E.; Bauer, F. E. +9 more
We present near-infrared integral-field spectroscopic observations targeting Hα in eight submillimeter galaxies (SMGs) at z = 1.3-2.5 using the Very Large Telescope/Spectrograph for Integral Field Observations in the Near Infrared, obtaining significant detections for six of them. The star formation rates derived from the Hα emission are ∼100 M
Multi-wavelength Study of Transition Region Penumbral Subarcsecond Bright Dots Using IRIS and NST
Xu, Yan; Liu, Chang; Wang, Haimin +4 more
Using high-resolution transition region (TR) observations taken by the Interface Region Imaging Spectrograph (IRIS) mission, Tian et al. revealed numerous short-lived subarcsecond bright dots (BDs) above sunspots (mostly located in the penumbrae), which indicate yet unexplained small-scale energy releases. Moreover, whether or not these subarcseco…
Narrow-line-width UV Bursts in the Transition Region above Sunspots Observed by IRIS
Fu, Hui; Madjarska, Maria S.; Li, Bo +5 more
Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si IV line profiles as found in observations taken with t…