8 research outputs found
Molecular gas in QSO host galaxies
We present the results of a survey for CO line emission from a sample of
nearby QSO hosts taken from the Hamburg/ESO survey (HES) and the Veron-Cetty
and Veron quasar catalogue. From a total of 39 observed sources we clearly
detected 5 objects with >10sigma signals (HE 0108-4743, HE 0224-2834,
J035818.7-612407, HE 1029-1831, HE 2211-3903). Further 6 sources show marginal
detections on the 2sigma level.Comment: 4 pages, 1 figure, submitted to "QSO Hosts: Evolution and
Environment", P.D. Barthel, D.B. Sanders, eds., August 2005, Leiden
University (The Netherlands), New Astr. Re
The balloon experimental twin telescope for infrared interferometry (BETTII): An experiment for high angular resolution in the far-infrared
The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is a new balloon-borne far-infrared interferometer, being designed to provide spatially-resolved spectroscopy in the far infrared (30â90 ÎŒm). The combination of an 8-meter baseline with a double-Fourier Michelson interferometer allows the identification and separation of closely-spaced astronomical sources, while also providing a low-resolution spectrum for each source. In this wavelength range, BETTII will provide subarcsecond angular resolution, a capability unmatched by other far-infrared facilities. This paper provides an overview of the entire design of the BETTII experiment, with a short discussion of the predicted performance on flight
Molecular gas in AzTEC/C159: a star-forming disk galaxy 1.3 Gyr after the Big Bang
We studied the molecular gas properties of AzTEC/C159, a star-forming disk galaxy at z = 4.567, in order to better constrain the nature of the high-redshift end of the submillimeter-selected galaxy (SMG) population. We secured 12CO molecular line detections for the J = 2 â1 and J = 5 â4 transitions using the Karl G. Jansky Very Large Array (VLA) and the NOrthern Extended Millimeter Array (NOEMA) interferometer. The broad (FWHM ~ 750 km sâ1) and tentative double-peaked profiles of the two 12CO lines are consistent with an extended molecular gas reservoir, which is distributed in a rotating disk, as previously revealed from [CII] 158 ÎŒm line observations. Based on the 12CO(2 â1) emission line, we derived LâČCO=(3.4±0.6)Ă1010âKâkmâsâ1âpc2, which yields a molecular gas mass of MH2(αCO/4.3)=(1.5±0.3)Ă1011âMâ and unveils a gas-rich system with ÎŒgas(αCO/4.3)âĄMH2/Mâ=3.3±0.7. The extreme star formation efficiency of AzTEC/C159, parametrized by the ratio LIR/LâČCO=(216±80)âLââ(Kâkmâsâ1âpc2)â1, is comparable to merger-driven starbursts such as local ultra-luminous infrared galaxies and SMGs. Likewise, the 12CO(5 â4)/CO(2 â1) line brightness temperature ratio of r52 = 0.55 ± 0.15 is consistent with high-excitation conditions as observed in SMGs. Based on mass budget considerations, we constrained the value for the LâČCO â H2 mass conversion factor in AzTEC/C159, that is, αCO=3.9â1.3+2.7âMââKâ1âkmâ1âsâpcâ2, which is consistent with a self-gravitating molecular gas distribution as observed in local star-forming disk galaxies. Cold gas streams from cosmological filaments might be fueling a gravitationally unstable gas-rich disk in AzTEC/C159, which breaks into giant clumps and forms stars as efficiently as in merger-driven systems and generates high gas excitation. These results support the evolutionary connection between AzTEC/C159-like systems and massive quiescent disk galaxies at z ~ 2
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Origins Space Telescope science drivers to design traceability
The Origins Space Telescope (Origins) concept is designed to investigate the creation and dispersal of elements essential to life, the formation of planetary systems, and the transport of water to habitable worlds and the atmospheres of exoplanets around nearby K-and M-dwarfs to identify potentially habitable-and even inhabited-worlds. These science priorities are aligned with NASA's three major astrophysics science goals: How does the Universe work? How did we get here? and Are we alone? We briefly describe the science case that arose from the astronomical community and the science traceability matrix for Origins. The science traceability matrix prescribes the design of Origins and demonstrates that it will address the key science questions motivated by the science case. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Herschel-ATLAS : a binary HyLIRG pinpointing a cluster of starbursting protoellipticals
Panchromatic observations of the best candidate hyperluminous infrared galaxies from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z = 2.41 galaxies across an â100 kpc regionâa cluster of starbursting protoellipticals. Via subarcsecond interferometric imaging we have measured accurate gas and star formation surface densities. The two brightest galaxies span ~3 kpc FWHM in submillimeter/radio continuum and CO J = 4-3, and double that in CO J = 1-0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disksâa scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M dyn of several Ă 1011 M â, and gas fractions of ~40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star formation rates place them >~ 5 Ă above the main sequence, which supposedly comprises large gas disks like these. Their high star formation efficiencies are difficult to reconcile with a simple volumetric star formation law. N-body and dark matter simulations suggest that this system is the progenitor of a B(inary)-type â1014.6-M â cluster