Search Publications
Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations
Schaefer, Gail H.; Bond, Howard E.; Evans, Nancy Remage +7 more
We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposure…
Spectroscopic Orbits for 15 Late-type Stars
Abt, Helmut A.; Fekel, Francis C.; Willmarth, Daryl W. +1 more
Spectroscopic orbital elements are determined for 15 stars with periods from 8 to 6528 days with six orbits computed for the first time. Improved astrometric orbits are computed for two stars and one new orbit is derived. Visual orbits were previously determined for four stars, four stars are members of multiple systems, and five stars have Hippar…
SOFIA Mid-infrared Imaging1 and CSO Submillimeter Polarimetry Observations of G034.43+00.24 MM1
Gehrz, R. D.; Vaillancourt, John E.; Shenoy, Dinesh +3 more
We present 11.1 to 37.1 µm imaging observations of the very dense molecular cloud core MM1 in G034.43+00.24 using FORCAST on SOFIA and submillimeter (submm) polarimetry using SHARP on the Caltech Submillimeter Observatory. We find that at the spatial resolution of SOFIA, the point-spread function (PSF) of MM1 is consistent with being a singl…
Detection of H I in Emission in the LYα Emitting Galaxy Haro 11
Cannon, John M.; Hayes, Matthew; Östlin, Göran +2 more
We present the first robust detection of H I 21 cm emission in the blue compact galaxy Haro 11 using the 100 m Robert C. Byrd Green Bank Telescope (GBT). Haro 11 is a luminous blue compact galaxy with emission in both Lyα and the Lyman continuum. We detect (5.1 ± 0.7 × 108) M ⊙ of H I gas at an assumed distance of 88 Mpc, mak…
A High-resolution Multiband Survey of Westerlund 2 with the Hubble Space Telescope. II. Mass Accretion in the Pre-main-sequence Population
Grebel, Eva K.; Bonanos, Alceste Z.; Sabbi, Elena +5 more
We present a detailed analysis of the pre-main-sequence (PMS) population of the young star cluster Westerlund 2 (Wd2), the central ionizing cluster of the H II region RCW 49, using data from a high-resolution multiband survey with the Hubble Space Telescope. The data were acquired with the Advanced Camera for Surveys in the F555W, F814W, and F658N…
GW Librae: Still Hot Eight Years Post-outburst
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +8 more
We report continued Hubble Space Telescope (HST) ultraviolet spectra and ground-based optical photometry and spectroscopy of GW Librae eight years after its largest known dwarf nova outburst in 2007. This represents the longest cooling timescale measured for any dwarf nova. The spectra reveal that the white dwarf still remains about 3000 K hotter …
The Time Evolution of HH 1 from Four Epochs of HST Images
Bally, J.; Raga, A. C.; Esquivel, A. +1 more
We present an analysis of four epochs of Hα and [S II] λλ 6716/6731 Hubble Space Telescope (HST) images of HH 1. For determining proper motions, we explore a new method based on the analysis of spatially degraded images obtained convolving the images with wavelet functions of chosen widths. With this procedure, we are able to generate maps of prop…
A Global Astrometric Solution for Pan-STARRS Referenced to ICRF2
Frouard, J.; Dorland, B. N.; Makarov, V. V. +13 more
We describe the development and application of a Global Astrometric Solution (GAS) to the problem of Pan-STARRS1 (PS1) astrometry. Current PS1 astrometry is based on differential astrometric measurements using 2MASS reference stars, and thus PS1 astrometry inherits the errors of the 2MASS catalog. The GAS, based on a single, least-squares adjustme…
Near-infrared Circular and Linear Polarimetry of Monoceros R2
Kwon, Jungmi; Nagata, Tetsuya; Tamura, Motohide +2 more
We have conducted simultaneous JHK s -band imaging circular and linear polarimetry of the Monoceros R2 (Mon R2) cluster. We present results from deep and wide near-infrared linear polarimetry of the Mon R2 region. Prominent and extended polarized nebulosities over the Mon R2 field are revisited, and an infrared reflection nebula associ…
The Kinematics of the Nebular Shells Around Low Mass Progenitors of PNe with Low Metallicity
Richer, Michael G.; López, José Alberto; Pereyra, Margarita
We analyze the internal kinematics of 26 planetary nebulae (PNe) with low metallicity that appear to derive from progenitor stars of the lowest masses, including the halo PN population. Based upon spatially resolved, long-slit, echelle spectroscopy drawn from the San Pedro Mártir Kinematic Catalog of PNe, we characterize the kinematics of these PN…