Search Publications
An ALMA/HST Study of Millimeter Dust Emission and Star Clusters
Dale, D. A.; Calzetti, D.; Smith, L. J. +7 more
We present results from a joint ALMA/HST study of the nearby spiral galaxy NGC 628. We combine the Hubble Space Telescope (HST) Legacy ExtraGalactic UV Survey (LEGUS) database of over 1000 stellar clusters in NGC 628 with ALMA Cycle 4 mm/submillimeter observations of the cold dust continuum that span ∼15 kpc2 including the nuclear regio…
Hubble Space Telescope Far-UV Spectroscopy of the Short Orbital Period Recurrent Nova CI Aql: Implications for White Dwarf Mass Evolution
Williams, Robert E.; Wilson, R. E.; Sion, Edward M. +3 more
An Hubble Space Telescope Cosmic Object Spectrograph Far UV spectrum (1170 Å to 1800 Å) was obtained for the short orbital period recurrent novae (T Pyxidis subclass), CI Aquilae. CI Aql is the only classical Cataclysmic variable (CV) known to have two eclipses of a sensible depth per orbit cycle and also to have pre- and post-outburst light curve…
Discovery and Identification of MAXI J1621-501 as a Type I X-Ray Burster with a Super-orbital Period
Göğüş, Ersin; Bahramian, Arash; Chakrabarty, Deepto +26 more
MAXI J1621-501 is the first Swift/XRT Deep Galactic Plane Survey transient that was followed up with a multitude of space missions (NuSTAR, Swift, Chandra, NICER, INTEGRAL, and MAXI) and ground-based observatories (Gemini, IRSF, and ATCA). The source was discovered with MAXI on 2017 October 19 as a new, unidentified transient. Further observations…
Chromospheric UV Bursts and Turbulent-driven Magnetic Reconnection
Wu, Pin
We use Interface Region Imaging Spectrograph (IRIS) spacecraft data to study a group of Chromospheric ultraviolet bursts (UVBs) associated with an active region. We classify the UVBs into two types: smaller ones that can only be measured once by the scanning slit, and larger UVBs that are measured twice by the slit. The UVBs’ optically thin Si IV …
A Recipe for Finding Stellar Radii, Temperatures, Surface Gravities, Metallicities, and Masses Using Spectral Lines
Gray, David F.; Kaur, Taranpreet
A recipe based on physical principles employs the observed equivalent widths of 10 spectral lines to model the photosphere of a target star. Coupled with the visual magnitude and an absolute flux calibration, the recipe yields the angular radius, effective temperature, surface gravity, and metallicity. With the addition of a parallax, a linear rad…
ALMA, ATCA, and Spitzer Observations of the Luminous Extragalactic Supernova SN 1978K
Kotak, R.; Ryder, S. D.; Smith, I. A. +2 more
Only three extragalactic supernovae have been detected at late times at millimeter wavelengths: SN 1987A, SN 1978K, and SN 1996cr. SN 1978K is a remarkably luminous Type IIn supernova that remains bright at all wavelengths 40 years after its explosion. Here, we present Atacama Large Millimeter/submillimeter Array (ALMA) observations taken in 2016 …
Kinetic Theory of Ion Acoustic Waves Observed at Comet 67P/Churyumov-Gerasimenko
Rehman, Saeed ur; Shah, Asif; Haque, Qamar ul
This work presents the resonance interaction of ion acoustic waves with the cometary plasma as observed at comet 67P/Churyumov-Gerasimenko. The plasma is comprised of cold, warm, and suprathermal electron populations and water ions such that the quasineutrality is satisfied. The cold electron population is found to play a dominant role in the damp…
Exploring the Asymmetry of the Solar Corona Electron Density with Very Long Baseline Interferometry
Pavlov, Dmitry; Melnikov, Alexey; Aksim, Dan +1 more
The Sun’s corona has interested researchers for multiple reasons, including the search for a solution to the famous coronal heating problem and a purely practical consideration of predicting geomagnetic storms on Earth. There exist numerous different theories regarding the solar corona; therefore, it is important to be able to perform comparative …
Absolute Dimensions of the Early F-type Eclipsing Binary V506 Ophiuchi
Torres, Guillermo; Fekel, Francis C.; Muterspaugh, Matthew W. +1 more
We report extensive differential V-band photometry and high-resolution spectroscopic observations of the early F-type, 1.06-day detached eclipsing binary V506 Oph. The observations, along with times of minimum light from the literature, are used to derive a very precise ephemeris and the physical properties for the components, with the absolute ma…
Discovery of Two Quasars at z = 5 from the OGLE Survey
Greiner, J.; Soszyński, I.; Udalski, A. +17 more
We used Optical Gravitational Lensing Experiment (OGLE-IV) deep (stacked) images (V ≲ 23 mag, I ≲ 23 mag at 3σ) of the Magellanic System, encompassing an area of ∼670 deg2, to perform a search for high-z quasar candidates. We combined the optical OGLE data with the mid-IR Wide-field Infrared Survey Explorer 3.4/4.6/12 µm data, and…