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Full-Text Articles in Physics
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. …
Agn Dusty Tori. Ii. Observational Implications Of Clumpiness, Maia Nenkova, Matthew M. Sirocky, Robert Nikutta, Željko Ivezić, Moshe Elitzur
Agn Dusty Tori. Ii. Observational Implications Of Clumpiness, Maia Nenkova, Matthew M. Sirocky, Robert Nikutta, Željko Ivezić, Moshe Elitzur
Physics and Astronomy Faculty Publications
Clumpy torus models with N0 ~ 5–15 dusty clouds along radial equatorial rays successfully explain AGN infrared observations. The dust has standard Galactic composition, with individual cloud optical depth τV ~ 30–100 at visual. The models naturally explain the observed behavior of the 10 μm silicate feature, in particular the lack of deep absorption features in AGNs of any type, and can reproduce the weak emission feature tentatively detected in type 2 QSOs. The clouds' angular distribution must have a soft edge, e.g., Gaussian, and the radial distribution should decrease as 1/r or 1/r2 …
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.