Search Publications
On the Nature of Hard X-Ray Extragalactic Sources Observed with XMM-Newton
Schartel, N.; Santos-Lleó, M.; Jiménez-Bailón, E. +3 more
Over the last decade, X-ray surveys have provided outstanding new results due to the lack of the common selection effects present at other wavelengths. Here, we have selected a sample of unidentified sources from the XMM-Newton Slew Survey Catalog, likely to be extragalactic. Five of them were observed with the XMM-Newton observatory. In this work…
The Nature of a Galaxy along the Sight Line to PKS 0454+039
Kulkarni, Varsha P.; Gharanfoli, Soheila; Takamiya, Marianne +1 more
We report on the properties of a faint blue galaxy (G1) along the line of sight to the QSO PKS 0454+039 from spectroscopic and imaging data. We measured emission lines of Hα, [S II] λλ6716, 6732, and [N II] λ6584 in the spectrum of G1 obtained with the Gemini/GMOS instrument. The spectroscopic redshift of G1 is z = 0.0715 ± 0.0002. From the extinc…
An All-sky Catalog of Bright M Dwarfs
Gaidos, Eric; Lépine, Sébastien
We present an all-sky catalog of M dwarf stars with apparent infrared magnitude J < 10. The 8889 stars are selected from the ongoing SUPERBLINK survey of stars with proper motion µ > 40 mas yr-1, supplemented on the bright end with the Tycho-2 catalog. Completeness tests which account for kinematic (proper motion) bias sugge…
Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System
Morris, Mark R.; Sahai, Raghvendra; Villar, Gregory G.
Using Hubble Space Telescope images of 119 young planetary nebulae (PNs), most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of PNs. Unlike previous c…
The Relationships among Compact Stellar Systems: A Fresh View of Ultracompact Dwarfs
Forbes, Duncan A.; Romanowsky, Aaron J.; Brodie, Jean P. +1 more
We use a combined imaging and spectroscopic survey of the nearby central cluster galaxy, M87, to assemble a sample of 34 confirmed ultracompact dwarfs (UCDs) with half-light radii of gsim10 pc measured from Hubble Space Telescope images. This doubles the existing sample in M87, making it the largest such sample for any galaxy, while extending the …
Star Clusters in M31. II. Old Cluster Metallicities and Ages from Hectospec Data
Caldwell, Nelson; Harding, Paul; Rose, James A. +2 more
We present new high signal-to-noise spectroscopic data on the M31 globular cluster (GC) system, obtained with the Hectospec multifiber spectrograph on the 6.5 m MMT. More than 300 clusters have been observed at a resolution of 5 Å and with a median S/N of 75 per Å, providing velocities with a median uncertainty of 6 km s-1. The primary …
The Southern Proper Motion Program. IV. The SPM4 Catalog
Beers, Timothy C.; Lee, Young Sun; Casetti-Dinescu, Dana I. +8 more
We present the fourth installment of the Yale/San Juan Southern Proper Motion Catalog, SPM4. The SPM4 contains absolute proper motions, celestial coordinates, and B, V photometry for over 103 million stars and galaxies between the south celestial pole and -20° declination. The catalog is roughly complete to V = 17.5 and is based on photographic an…
Distance Scale Zero Points from Galactic RR Lyrae Star Parallaxes
Kochukhov, Oleg; Nelan, Edmund P.; Freedman, Wendy L. +15 more
We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars—five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and κ Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. W…
Star Clusters in M31. V. Internal Dynamical Trends: Some Troublesome, Some Reassuring
Caldwell, Nelson; Strader, Jay; Seth, Anil C.
We present internal velocity dispersions and precise radial velocities for 200 globular clusters (GCs) in M31 that are derived using new high-resolution spectra from MMT/Hectochelle. Of these, 163 also have King model structural parameters that allow us to estimate their mass-to-light ratios. This is, by far, the largest such data set available fo…
The Nuclear Structure in Nearby Luminous Infrared Galaxies: Hubble Space Telescope NICMOS Imaging of the GOALS Sample
Sanders, D. B.; Surace, J. A.; Inami, H. +16 more
We present results of Hubble Space Telescope (HST) NICMOS H-band imaging of 73 of the most luminous (i.e., log[L IR/L sun]>11.4) infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. This data set combines multi-wavelength imaging and spectroscopic data from space-based (Spitzer, HST, GALEX, and Chandra…