Search Publications
Unambiguous Detection of Reflection in Magnetic Cataclysmic Variables: Joint NuSTAR-XMM-Newton Observations of Three Intermediate Polars
Mukai, K.; de Martino, D.; Bernardini, F. +1 more
In magnetic cataclysmic variables (CVs), X-ray emission regions are located close to the white dwarf surface, which is expected to reflect a significant fraction of intrinsic X-rays above 10 keV, producing a Compton reflection hump. However, up to now, a secure detection of this effect in magnetic CVs has largely proved elusive because of the limi…
Direct Observations of Magnetic Reconnection Outflow and CME Triggering in a Small Erupting Solar Prominence
Reeves, Katharine K.; Tian, Hui; McCauley, Patrick I.
We examine a small prominence eruption that occurred on 2014 May 1 at 01:35 UT and was observed by the Interface Region Imaging Spectrometer (IRIS) and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. Pre- and post-eruption images were taken by the X-ray Telescope (XRT) on Hinode. Pre-eruption, a dome-like structure exists…
Calibrating UV Star Formation Rates for Dwarf Galaxies from STARBIRDS
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Skillman, Evan D. +1 more
Integrating our knowledge of star formation (SF) traced by observations at different wavelengths is essential for correctly interpreting and comparing SF activity in a variety of systems and environments. This study compares extinction corrected integrated ultraviolet (UV) emission from resolved galaxies with color-magnitude diagram (CMD) based st…
Atomic Data and Spectral Model for Fe II
Kallman, Timothy R.; Bautista, Manuel A.; Mendoza, Claudio +4 more
We present extensive calculations of radiative transition rates and electron impact collision strengths for Fe ii. The data sets involve 52 levels from the 3d7, 3d64s, and 3{d}54{s}2 configurations. Computations of A-values are carried out with a combination of state-of-the-art multiconfiguration approac…
Leo P: How Many Metals Can a Very Low Mass, Isolated Galaxy Retain?
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +7 more
Leo P is a gas-rich dwarf galaxy with an extremely low gas-phase oxygen abundance (3% solar). The isolated nature of Leo P enables a quantitative measurement of metals lost solely due to star formation feedback. We present an inventory of the oxygen atoms in Leo P based on the gas-phase oxygen abundance measurement, the star formation history (SFH…
Re-visit of HST FUV Observations of the Hot-Jupiter System HD 209458: No Si III Detection and the Need for COS Transit Observations
Ballester, G. E.; Ben-Jaffel, L.
The discovery of O i atoms and C ii ions in the upper atmosphere of HD 209458b, made with the Hubble Space Telescope Imaging Spectrograph (STIS) using the G140L grating, showed that these heavy species fill an area comparable to the planet’s Roche lobe. The derived ∼10% transit absorption depths require super-thermal processes and/or supersolar ab…
Low Angular Momentum in Clumpy, Turbulent Disk Galaxies
Glazebrook, Karl; Obreschkow, Danail; Abraham, Roberto G. +8 more
We measure the stellar specific angular momentum {j}s={J}s/{M}s in four nearby (z ≈ 0.1) disk galaxies that have stellar masses {M}s near the break {M}s* of the galaxy mass function but look like typical star-forming disks at z ≈ 2 in terms of their low stability (Q ≈ 1), clumpiness…
A Type II Radio Burst without a Coronal Mass Ejection
Cheng, X.; Ding, M. D.; Chen, P. F. +2 more
Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II radio burst is not accompanied by a coronal mass ejection, only by a C2.4 class flare and narrow jet. However, i…
A Light Curve Analysis of Classical Novae: Free-free Emission versus Photospheric Emission
Kato, Mariko; Hachisu, Izumi
We analyzed light curves of seven relatively slower novae, PW Vul, V705 Cas, GQ Mus, RR Pic, V5558 Sgr, HR Del, and V723 Cas, based on an optically thick wind theory of nova outbursts. For fast novae, free-free emission dominates the spectrum in optical bands rather than photospheric emission, and nova optical light curves follow the universal dec…
Chitah: Strong-gravitational-lens Hunter in Imaging Surveys
Marshall, Philip J.; Oguri, Masamune; Suyu, Sherry H. +5 more
Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling t…