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Three New Cool Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer (WISE) and an Improved Spectrum of the Y0 Dwarf WISE J041022.71+150248.4
Gould, Andrew; Cushing, Michael C.; Kirkpatrick, J. Davy +3 more
As part of a larger search of Wide-field Infrared Survey Explorer (WISE) data for cool brown dwarfs with effective temperatures less than 1000 K, we present the discovery of three new cool brown dwarfs with spectral types later than T7. Using low-resolution, near-infrared spectra obtained with the NASA Infrared Telescope Facility and the Hubble Sp…
The Luminosity Function of Star Clusters in 20 Star-forming Galaxies Based on Hubble Legacy Archive Photometry
Whitmore, Bradley C.; Chandar, Rupali; Ansari, Asna +4 more
Luminosity functions (LFs) have been determined for star cluster populations in 20 nearby (4-30 Mpc), star-forming galaxies based on Advanced Camera for Surveys source lists generated by the Hubble Legacy Archive (HLA). These cluster catalogs provide one of the largest sets of uniform, automatically generated cluster candidates available in the li…
Spectral Energy Distribution Analysis of Class I and Class II FU Orionis Stars
Gramajo, Luciana V.; Gómez, Mercedes; Rodón, Javier A.
FU Orionis stars (FUors) are eruptive pre-main sequence objects thought to represent quasi-periodic or recurring stages of enhanced accretion during the low-mass star-forming process. We characterize the sample of known and candidate FUors in a homogeneous and consistent way, deriving stellar and circumstellar parameters for each object. We emphas…
Hubble Space Telescope Imaging of Decoupled Dust Clouds in the Ram Pressure Stripped Virgo Spirals NGC 4402 and NGC 4522
Kenney, Jeffrey D. P.; Abramson, Anne
We present the highest-resolution study to date of the interstellar medium (ISM) in galaxies undergoing ram pressure stripping, using Hubble Space Telescope BVI imaging of NGC 4522 and NGC 4402, Virgo Cluster spirals that are well known to be experiencing intracluster medium (ICM) ram pressure. We find that throughout most of both galaxies, the ma…
The Ups and Downs of α Centauri
Ayres, Thomas R.
The following is a progress report on the long-term coronal (T ~ 1 MK) activity of α Centauri A (HD 128620: G2 V) and B (HD 128621: K1 V). Since 2005, Chandra X-Ray Observatory has carried out semiannual pointings on AB, mainly with the High Resolution Camera, but also on two occasions with the Low-Energy Transmission Grating Spectrometer, fully r…
A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors
Herrero, A.; Gies, D. R.; Moffat, A. F. J. +8 more
We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference ΔV < 4 down to separations as small as 0.''01. The sample includes 58 of the bright…
Prospects for Measuring Supermassive Black Hole Masses with Future Extremely Large Telescopes
Barth, Aaron J.; Do, Tuan; Larkin, James E. +6 more
The next generation of giant-segmented mirror telescopes (>20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole ma…
A CO Survey in Planet-forming Disks: Characterizing the Gas Content in the Epoch of Planet Formation
Ménard, F.; Casassus, S.; Eiroa, C. +13 more
We carried out a 12CO(3-2) survey of 52 southern stars with a wide range of IR excesses (L IR/L *) using the single-dish telescopes APEX and ASTE. The main aims were (1) to characterize the evolution of molecular gas in circumstellar disks using L IR/L * values as a proxy of disk dust evolutio…
Astrometrically Registered Simultaneous Observations of the 22 GHz H2O and 43 GHz SiO Masers toward R Leonis Minoris Using KVN and Source/Frequency Phase Referencing
Byun, Do-Young; Kim, Jongsoo; Kim, Kee-Tae +22 more
Oxygen-rich asymptotic giant branch (AGB) stars can be intense emitters of SiO (v = 1 and 2, J = 1 → 0) and H2O maser lines at 43 and 22 GHz, respectively. Very long baseline interferometry (VLBI) observations of the maser emission provide a unique tool to probe the innermost layers of the circumstellar envelopes in AGB stars. Neverthel…
The Solar Neighborhood. XXXI. Discovery of an Unusual Red+White Dwarf Binary at ~25 pc via Astrometry and UV Imaging
Gies, Douglas R.; Henry, Todd J.; Winters, Jennifer G. +4 more
We report the discovery of a nearby M5.0V dwarf at 24.6 pc, SCR 1848-6855, that is orbited by an unusual companion causing an astrometric perturbation of more than 200 mas. This is by far the largest perturbation found to date among more than 700 targets observed during our long-term astrometry/photometry program at the CTIO 0.9 m telescope. We pr…