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Full-Text Articles in Physical Sciences and Mathematics
The Energetics Of Molecular Gas In Ngc 891 From H2 And Far-Infrared Spectroscopy, G. J. Stacey, Vassilis Charmandaris, F. Boulanger, Yanling Wu, F. Combes, S. J. U. Higdon, J. D. T. Smith, T. Nikola
The Energetics Of Molecular Gas In Ngc 891 From H2 And Far-Infrared Spectroscopy, G. J. Stacey, Vassilis Charmandaris, F. Boulanger, Yanling Wu, F. Combes, S. J. U. Higdon, J. D. T. Smith, T. Nikola
Department of Physics and Astronomy Faculty Publications
We have studied the molecular hydrogen energetics of the edge-on spiral galaxy NGC?891, using a 34 position map in the lowest three pure rotational H2 lines observed with the Spitzer Infrared Spectrograph. The S(0), S(1), and S(2) lines are bright with an extinction-corrected total luminosity of ~2.8 × 107 L ?, or 0.09% of the total-infrared luminosity of NGC?891. The H2 line ratios are nearly constant along the plane of the galaxy?we do not observe the previously reported strong drop-off in the S(1)/S(0) line intensity ratio in the outer regions of the galaxy, so …
Pah Emission From Ultraluminous Infrared Galaxies, V. Desai, L. Armus, H. W. W. Spoon, Vassilis Charmandaris, J. Bernard-Salas, B. R. Brandl, D. Farrah, B.T. Soifer, H. I. Teplitz, P. M. Ogle, D. Devost, Sarah J.U. Higdon, J. A. Marshall, J. R. Houck
Pah Emission From Ultraluminous Infrared Galaxies, V. Desai, L. Armus, H. W. W. Spoon, Vassilis Charmandaris, J. Bernard-Salas, B. R. Brandl, D. Farrah, B.T. Soifer, H. I. Teplitz, P. M. Ogle, D. Devost, Sarah J.U. Higdon, J. A. Marshall, J. R. Houck
Department of Physics and Astronomy Faculty Publications
We explore the relationships between the Polycyclic Aromatic Hydrocarbon (PAH) feature strengths, mid-infrared continuum luminosities, far-infrared spectral slopes, optical spectroscopic classifications, and silicate optical depths within a sample of 107 ULIRGs observed with the Infrared Spectrograph on the Spitzer Space Telescope. The detected 6.2 µm PAH equivalent widths (EQWs) in the sample span more than two orders of magnitude (∼0.006–0.8 µm), and ULIRGs with HII-like optical spectra or steep far-infrared spectral slopes (S25/S60 < 0.2) typically have 6.2 µm PAH EQWs that are half that of lower-luminosity starbursts. A significant fraction (∼40–60%) of HII-like, LINER-like, and cold ULIRGs have very weak PAH EQWs. Many of these ULIRGs also have large (τ9.7 > 2.3) silicate optical depths. The far-infrared spectral slope is strongly correlated with PAH EQW, but not with silicate optical depth. In addition, the PAH EQW decreases with …
Hubble Space Telescope Morphologies Of Z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources, R.S. Bussman, Arjun Dey, J. Lotz, Lee Armus, Kate Brand, Michael J. I. Brown, Vandana Desai, Peter Eisenhardt, James L. Higdon, Sarah J.U. Higdon, B. T. Jannuzi, Emeric Le Floc'h, J. Melbourne, B. T. Soifer, Daniel Weedman
Hubble Space Telescope Morphologies Of Z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources, R.S. Bussman, Arjun Dey, J. Lotz, Lee Armus, Kate Brand, Michael J. I. Brown, Vandana Desai, Peter Eisenhardt, James L. Higdon, Sarah J.U. Higdon, B. T. Jannuzi, Emeric Le Floc'h, J. Melbourne, B. T. Soifer, Daniel Weedman
Department of Physics and Astronomy Faculty Publications
We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24µm–bright z ≈ 2 Dust Obscured Galaxies (DOGs) identified in the Bo¨otes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V − H and I − H colors of the extended components are 0.2−3 …
Radio And Infrared Selected Optically Invisible Sources In The Boötes Ndwfs, James L. Higdon, Sarah J.U. Higdon, Steven P. Willner, Michael J. I. Brown, D. Stern, Emeric Le Floc'h, Peter Eisenhardt
Radio And Infrared Selected Optically Invisible Sources In The Boötes Ndwfs, James L. Higdon, Sarah J.U. Higdon, Steven P. Willner, Michael J. I. Brown, D. Stern, Emeric Le Floc'h, Peter Eisenhardt
Department of Physics and Astronomy Faculty Publications
We have combined data from the NOAO Deep Wide-Field Survey in Bo¨otes and the Spitzer Space Telescope to determine basic properties for sixteen optically “invisible” MIPS 24 µm (OIMS) and thirty-five optically “invisible” radio (OIRS) sources, including their spectral energy distributions (SED) and luminosities. Most OIMSs possess steep power-law SEDs over λrest = 1 − 10 µm, indicating the presence of obscured AGN in agreement with Spitzer spectroscopy. These objects are extremely luminous at rest-frame near and mid-IR (νLν(5 µm) ≈ 1038 − 1039 W), consistent with accretion near the Eddington limit and further implying that they host buried QSOs. …
Spitzer Observations Of Tidal Dwarf Galaxies, Sarah J.U. Higdon, James L. Higdon
Spitzer Observations Of Tidal Dwarf Galaxies, Sarah J.U. Higdon, James L. Higdon
Department of Physics and Astronomy Faculty Publications
We present Spitzer observations of Tidal Dwarf Galaxies (TDGs) in three interacting systems: NGC 5291, Arp 105 & Stephan’s Quintet. The spectra show bright emission from polyaromatic hydrocarbons (PAHs), nebular lines and warm molecular hydrogen, characteristic of recent episodes of star formation. The PAH emission that falls in the IRAC 8.0 µm band leads to the TDGs having an extremely red IRAC color, with [4.5] − [8.0] > 3. The emission from PAHs is characterized by a model with mainly neutral 100-C PAH atoms.
A Significant Population Of Very Luminous Dust-Obscured Galaxies At Redshift Z ~ 2, Arjun Dey, B.T. Soifer, Vandana Desai, Kate Brand, Emeric Le Floc'h, Michael J. I. Brown, Buell T. Jannuzi, Lee Armus, R. Shane Bussmann, Mark Brodwin, Chao Bian, Peter Eisenhardt, Sarah J.U. Higdon, Daniel Weedman, S. P. Willner
A Significant Population Of Very Luminous Dust-Obscured Galaxies At Redshift Z ~ 2, Arjun Dey, B.T. Soifer, Vandana Desai, Kate Brand, Emeric Le Floc'h, Michael J. I. Brown, Buell T. Jannuzi, Lee Armus, R. Shane Bussmann, Mark Brodwin, Chao Bian, Peter Eisenhardt, Sarah J.U. Higdon, Daniel Weedman, S. P. Willner
Department of Physics and Astronomy Faculty Publications
Observations with the Spitzer Space Telescope have recently revealed a significant population of high-redshift (z ∼ 2) dust-obscured galaxies (DOGs) with large (rest-frame) mid-infrared to ultraviolet luminosity ratios. Due to their optical faintness, these galaxies have been previously missed in traditional optical studies of the distant universe. We present a simple method for selecting this high-redshift population based solely on the ratio of the observed mid-infrared 24µm to optical R-band flux density. We apply this method to observations of the ≈ 8.6 deg2 Bo¨otes Field of the NOAO Deep Wide-Field Survey, and uncover ≈2,600 DOG candidates (i.e., a surface density …
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Department of Physics and Astronomy Faculty Publications
We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …