Search Publications
A Sea Change in Eta Carinae
Walborn, Nolan R.; Humphreys, Roberta M.; Davidson, Kris +4 more
Major stellar-wind emission features in the spectrum of η Car have recently decreased by factors of order 2 relative to the continuum. This is unprecedented in the modern observational record. The simplest, but unproven, explanation is a rapid decrease in the wind density.
Non-parametric modeling of the intra-cluster gas using APEX-SZ bolometer imaging data
Zhang, Y. -Y.; Kneissl, R.; Menten, K. M. +23 more
Aims: We aim to demonstrate the usability of mm-wavelength imaging data obtained from the APEX-SZ bolometer array to derive the radial temperature profile of the hot intra-cluster gas out to radius r500 and beyond. The goal is to study the physical properties of the intra-cluster gas by using a non-parametric de-projection method t…
AKARI Observations of Brown Dwarfs. I. CO and CO2 Bands in the Near-infrared Spectra
Yamamura, Issei; Tanabé, Toshihiko; Tsuji, Takashi
Near-infrared medium-resolution spectra of seven bright brown dwarfs are presented. The spectra were obtained with the Infrared Camera on board the infrared astronomical satellite AKARI, covering 2.5-5.0 µm with a spectral resolution of approximately 120. The spectral types of the objects range from L5 to T8 and enable us to study the spectr…
Dwarf spheroidals in the M 81 group - Metallicity distribution functions and population gradients
Grebel, E. K.; Koch, A.; Lianou, S.
Aims: We study the dwarf spheroidal galaxies in the nearby M 81 group in order to construct their photometric metallicity distributions and to investigate the potential presence of population gradients. We select all the dwarf spheroidals with available Hubble Space Telescope / Advanced Camera for Surveys archival observations, nine in total.…
Taming the Invisible Monster: System Parameter Constraints for epsilon Aurigae from the Far-ultraviolet to the Mid-infrared
Stencel, R. E.; Hoard, D. W.; Howell, S. B.
We have assembled new Spitzer Space Telescope IRAC observations of the mysterious binary star epsilon Aurigae, along with archival far-ultraviolet to mid-infrared data, to form an unprecedented spectral energy distribution (SED) spanning 3 orders of magnitude in wavelength from 0.1 µm to 100 µm. The observed SED can be reproduced using…
Southern Cosmology Survey. II. Massive Optically Selected Clusters from 70 Square Degrees of the Sunyaev-Zel'dovich Effect Common Survey Area
Hilton, Matt; Hughes, John P.; Kosowsky, Arthur +8 more
We present a catalog of 105 rich and massive (M>3 × 1014 M sun) optically selected clusters of galaxies extracted from 70 deg2 of public archival griz imaging from the Blanco 4 m telescope acquired over 45 nights between 2005 and 2007. We use the clusters' optically derived properties to estimate photometric red…
First detection of ND in the solar-mass protostar IRAS16293-2422
Falgarone, E.; Maret, S.; Henning, T. +64 more
Context. In the past decade, much progress has been made in characterising the processes leading to the enhanced deuterium fractionation observed in the ISM and in particular in the cold, dense parts of star forming regions such as protostellar envelopes. Very high molecular D/H ratios have been found for saturated molecules and ions. However, lit…
(47171) 1999 TC 36, A transneptunian triple
Grundy, W. M.; Noll, K. S.; Benecchi, S. D. +1 more
We present new analysis of HST images of (47171) 1999 TC 36 that confirm it as a triple system. Fits to the point-spread function (PSF) consistently show that the apparent primary is itself composed of two similar-sized components. The two central components, A1 and A2, can be consistently identified in each of nine epochs spread over 7…
[CII] observations of H2 molecular layers in transition clouds
Li, D.; Goldsmith, P. F.; Langer, W. D. +3 more
We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 µm (1.9 THz) towards Galactic longitudes near 340° (5 LOSs) & 20° (11 LOSs) as part of the HIFI tests and GOT C+ survey. Out of the total 146 [CII] velocity components detected by profile fitting we identify 53 as diffuse molecular clouds…
X-ray and Radio Variability of M31*, The Andromeda Galaxy Nuclear Supermassive Black Hole
Melia, Fulvio; Murray, Stephen S.; Garcia, Michael R. +6 more
We confirm our earlier tentative detection of M31* in X-rays and measure its light curve and spectrum. Observations in 2004-2005 find M31* rather quiescent in the X-ray and radio. However, X-ray observations in 2006-2007 show M31* to be highly variable at times. A separate variable X-ray source is found near P1, the brighter of the two optical nuc…