210 research outputs found

    Basketball History

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    This article was prepared in August, 1950, by Edward R. Kirkpatrick for one of his duck dinners, but was never used. This document was presented to Illinois Wesleyan University by Mr. Charles Kirkpatrick at the special banquet honoring the basketball team of 1954 and their co-captains and the captains of preceding basketball teams back through the years. This document represents research by two brothers: Edward B. Kirkpatrick and Charles Kirkpatrick. Date April 2, 1954. Signed MJ

    The Porcupine Survey: A Distributed Survey and WISE Followup

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    Spitzer post-cryogen observations to perform a moderate depth survey distributed around the sky are proposed. Field centers are chosen to be WISE brown dwarf candidates, which will typically be 160 µJy at 4.7 µm and randomly distributed around the sky. The Spitzer observations will give much higher sensitivity, higher angular resolution, and a time baseline to measure both proper motions and possibly parallaxes. The distance and velocity data obtained on the WISE brown dwarf candidates will greatly improve our knowledge of the mass and age distribution of brown dwarfs. The outer parts of the Spitzer fields surrounding the WISE positions will provide a deep survey in many narrow fields of view distributed around the sky, and the volume of this survey will contain many more distant brown dwarfs, and many extragalactic objects

    WISE J163940.83-684738.6: A Y Dwarf identified by Methane Imaging

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    We have used methane imaging techniques to identify the near-infrared counterpart of the bright WISE source WISEJ163940.83-684738.6. The large proper motion of this source (around 3.0arcsec/yr) has moved it, since its original WISE identification, very close to a much brighter background star -- it currently lies within 1.5" of the J=14.90+-0.04 star 2MASS16394085-6847446. Observations in good seeing conditions using methane sensitive filters in the near-infrared J-band with the FourStar instrument on the Magellan 6.5m Baade telescope, however, have enabled us to detect a near-infrared counterpart. We have defined a photometric system for use with the FourStar J2 and J3 filters, and this photometry indicates strong methane absorption, which unequivocally identifies it as the source of the WISE flux. Using these imaging observations we were then able to steer this object down the slit of the FIRE spectrograph on a night of 0.6" seeing, and so obtain near-infrared spectroscopy confirming a Y0-Y0.5 spectral type. This is in line with the object's near-infrared-to-WISE J3--W2 colour. Preliminary astrometry using both WISE and FourStar data indicates a distance of 5.0+-0.5pc and a substantial tangential velocity of 73+-8km/s. WISEJ163940.83-684738.6 is the brightest confirmed Y dwarf in the WISE W2 passband and its distance measurement places it amongst the lowest luminosity sources detected to date.Comment: Accepted for publication in The Astrophysical Journal, 20 September 201

    WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System

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    The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies using high-resolution imaging cannot only uncover faint companions, but they can also be used to determine dynamical masses through long-term monitoring of binary systems. We have begun a search for the coolest brown dwarfs using preliminary processing of data from the Wide-field Infrared Survey Explorer and have confirmed many of the candidates as late-type T dwarfs. In order to search for companions to these objects, we are conducting observations using the Laser Guide Star Adaptive Optics system on Keck II. Here we present the first results of that search, including a T5 binary with nearly equal mass components and a faint companion to a T8.5 dwarf with an estimated spectral type of T9

    Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Luminous Infrared Galaxy Candidates

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    We present Spitzer 3.6 and 4.5 μ\mum photometry and positions for a sample of 1510 brown dwarf candidates identified by the WISE all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12); Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify 7 fainter (4.5 μ\mum \sim 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy (HyLIRG) candidates. For this control sample we find another 6 brown dwarf candidates, suggesting that the 7 companion candidates are not physically associated. In fact, only one of these 7 Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this there is no evidence for any widely separated (>> 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of \sim 7.33 ×105\times 10^5 objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 μ\mum photometry, along with positionally matched BB and RR photometry from USNO-B; JJ, HH, and KsK_s photometry from 2MASS; and W1W1, W2W2, W3W3, and W4W4 photometry from the WISE all-sky catalog

    Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer

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    We present a sample of brown dwarfs identified with the {\it Wide-field Infrared Survey Explorer} (WISE) for which we have obtained {\it Hubble Space Telescope} ({\it HST}) Wide Field Camera 3 (WFC3) near-infrared grism spectroscopy. The sample (twenty-two in total) was observed with the G141 grism covering 1.10-1.70 μ\mum, while fifteen were also observed with the G102 grism, which covers 0.90-1.10 μ\mum. The additional wavelength coverage provided by the G102 grism allows us to 1) search for spectroscopic features predicted to emerge at low effective temperatures (e.g.\ ammonia bands) and 2) construct a smooth spectral sequence across the T/Y boundary. We find no evidence of absorption due to ammonia in the G102 spectra. Six of these brown dwarfs are new discoveries, three of which are found to have spectral types of T8 or T9. The remaining three, WISE J082507.35++280548.5 (Y0.5), WISE J120604.38++840110.6 (Y0), and WISE J235402.77++024015.0 (Y1) are the nineteenth, twentieth, and twenty-first spectroscopically confirmed Y dwarfs to date. We also present {\it HST} grism spectroscopy and reevaluate the spectral types of five brown dwarfs for which spectral types have been determined previously using other instruments.Comment: Accepted for publication in the Astrophysical Journal. 20 pages, 18 figures, 7 table

    The Exemplar T8 Subdwarf Companion of Wolf 1130

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    We have discovered a wide separation (188.5") T8 subdwarf companion to the sdM1.5+WD binary Wolf 1130. Companionship of WISE J200520.38+542433.9 is verified through common proper motion over a ~3 year baseline. Wolf 1130 is located 15.83 +/- 0.96 parsecs from the Sun, placing the brown dwarf at a projected separation of ~3000 AU. Near-infrared colors and medium resolution (R~2000-4000) spectroscopy establish the uniqueness of this system as a high-gravity, low-metallicity benchmark. Although there are a number of low-metallicity T dwarfs in the literature, WISE J200520.38+542433.9 has the most extreme inferred metallicity to date with [Fe/H] = -0.64 +/- 0.17 based on Wolf 1130. Model comparisons to this exemplar late-type subdwarf support it having an old age, a low metallicity, and a small radius. However, the spectroscopic peculiarities of WISE J200520.38+542433.9 underscore the importance of developing the low-metallicity parameter space of the most current atmospheric models.Comment: Accepted to ApJ on 05 September 2013; 33 pages in preprint format, 8 figures, 3 table

    NEOWISE-R Observation of the Coolest Known Brown Dwarf

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    The Wide-field Infrared Survey Explorer (WISE) spacecraft has been reactivated as NEOWISE-R to characterize and search for Near Earth Objects. The brown dwarf WISE J085510.83-071442.5 has now been reobserved by NEOWISE-R, and we confirm the results of Luhman (2014b), who found a very low effective temperature (250\approx 250 K), a very high proper motion (8.1 +/- 0.1 arcsec/yr) , and a large parallax (454 +/- 45 mas). The large proper motion has separated the brown dwarf from the background sources that influenced the 2010 WISE data, allowing a measurement of a very red WISE color of W1-W2 >3.9> 3.9 mag. A re-analysis of the 2010 WISE astrometry using only the W2 band, combined with the new NEOWISE-R 2014 position, gives an improved parallax of 448 +/- 33 mas and proper motion of 8.08 +/- 0.05\; arcsec/yr. These are all consistent with Luhman (2014b).Comment: 6 pages, AJ accepte
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