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C III] Emission in Star-forming Galaxies Near and Far
Dahle, H.; Rigby, J. R.; Bayliss, M. B. +5 more
We measure [C iii] 1907, C iii] 1909 Å emission lines in 11 gravitationally lensed star-forming galaxies at z ∼ 1.6-3, finding much lower equivalent widths than previously reported for fainter lensed galaxies. While it is not yet clear what causes some galaxies to be strong C iii] emitters, C iii] emission is not a universal property of distant st…
A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. IV. A Multiwavelength, Non-LTE Spectroscopic Analysis
Corcoran, M. F.; Hamann, W. -R.; Nazé, Y. +13 more
Eclipsing systems of massive stars allow one to explore the properties of their components in great detail. We perform a multi-wavelength, non-LTE analysis of the three components of the massive multiple system δ Ori A, focusing on the fundamental stellar properties, stellar winds, and X-ray characteristics of the system. The primary’s distance-in…
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…
Variability of Disk Emission in Pre-main Sequence and Related Stars. III. Exploring Structural Changes in the Pre-transitional Disk in HD 169142
Inoue, Akio K.; Brown, Alexander; Russell, Ray W. +17 more
We present near-IR (NIR) and far-UV observations of the pre-transitional (gapped) disk in HD 169142 using NASA's Infrared Telescope Facility and Hubble Space Telescope. The combination of our data along with existing data sets into the broadband spectral energy distribution reveals variability of up to 45% between ~1.5-10 µm over a maximum t…
On the Origin of Wind Line Variability in O Stars
Massa, D.; Prinja, R. K.
We analyze 10 UV time series for five stars that fulfill specific sampling and spectral criteria to constrain the origin of large-scale wind structure in O stars. We argue that excited state lines must arise close to the stellar surface and are an excellent diagnostic complement to resonance lines which, due to radiative transfer effects, rarely s…
The Born-again Planetary Nebula A78: An X-Ray Twin of A30
Gruendl, R. A.; Hamann, W. -R.; Chu, Y. -H. +8 more
We present the XMM-Newton discovery of X-ray emission from the planetary nebula (PN) A78, the second born-again PN detected in X-rays apart from A30. These two PNe share similar spectral and morphological characteristics: they harbor diffuse soft X-ray emission associated with the interaction between the H-poor ejecta and the current fast stellar …
The 1999aa-like Type Ia Supernova iPTF14bdn in the Ultraviolet and Optical
Suntzeff, Nicholas B.; Wang, Xiaofeng; Zhang, Jujia +5 more
We present ultraviolet (UV) and optical photometry and spectra of the 1999aa-like supernova (SN) iPTF14bdn. The UV data were observed using the Swift Ultraviolet/Optical Telescope and constitute the first UV spectral series of a 1999aa-like SN. From the photometry, we measure Δm15(B) = 0.84 ± 0.05 mag and blue UV colors at epochs earlie…
A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. I. Overview of the X-Ray Spectrum
Gull, T. R.; Corcoran, M. F.; Owocki, S. P. +22 more
We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of δ Ori A. Delta Ori A is actually a triple system that includes the nearest massive eclipsing spectroscopic binary, δ Ori Aa, the only such object that can be observed with little phase-smearing with the Chandra gratings. Since the fainter star, δ Ori Aa2, has…
Far-ultraviolet Study of the ζ-Ophiuchi H II Region
Choi, Yeon-Ju; Min, Kyoung-Wook; Seon, Kwang-Il
We report the results of our analysis of the H II region around ζ Oph based on far-ultraviolet (FUV) spectral imaging observations, together with data made in other wavelengths. We found that scattering by dust grains of the FUV photons, which originate mostly from ζ Oph, dominates the FUV emission in this region, while contributions from the two-…
A Chandra Observation of the Eclipsing Wolf-Rayet Binary CQ Cep
Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel +1 more
The short-period (1.64 d) near-contact eclipsing WN6+O9 binary system CQ Cep provides an ideal laboratory for testing the predictions of X-ray colliding wind shock theory at close separation where the winds may not have reached terminal speeds before colliding. We present results of a Chandra X-ray observation of CQ Cep spanning ~1 day during whic…