Search Publications
The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus Models
Telesco, C. M.; Fisher, R. S.; Packham, C. +6 more
We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 µm of 18 Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral energy distributions (SEDs) that the active galactic nucleus (AGN) dominates, relatively uncontaminated by starlight,…
Massive Galaxies in COSMOS: Evolution of Black Hole Versus Bulge Mass but not Versus Total Stellar Mass Over the Last 9 Gyr?
Koekemoer, Anton M.; Trump, Jonathan R.; Comastri, Andrea +23 more
We constrain the ratio of black hole (BH) mass to total stellar mass of type-1 active galactic nuclei (AGNs) in the COSMOS survey at 1 < z < 2. For 10 AGNs at mean redshift z ~ 1.4 with both Hubble Space Telescope (HST)/ACS and HST/NICMOS imaging data, we are able to compute the total stellar mass M *,total, based on rest-frame UV…
Evidence for X-Ray Synchrotron Emission from Simultaneous Mid-Infrared to X-Ray Observations of a Strong Sgr A* Flare
Genzel, R.; Rouan, D.; Pantin, E. +22 more
This paper reports measurements of Sgr A* made with NACO in L' band (3.80 µm), Ks band (2.12 µm), and H band (1.66 µm), and with VISIR in N band (11.88 µm) at the ESO VLT, as well as with XMM-Newton at X-ray (2-10 keV) wavelengths. On 2007 April 4, a very bright flare was observed from Sgr A* simultaneously at L' band and X…
Clumpy Galaxies in Goods and Gems: Massive Analogs of Local Dwarf Irregulars
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Marcus, Max T. +3 more
Clumpy galaxies in the Galaxy Evolution from Morphology and SEDs and Great Observatories Origins Deep Survey fields are examined for clues to their evolution into modern spirals. The magnitudes of the clumps and the surface brightnesses of the interclump regions are measured and fitted to models of stellar age and mass. There is an evolutionary tr…
A Compton-thick Wind in the High-luminosity Quasar, PDS 456
Behar, E.; Turner, T. J.; Fabian, A. C. +7 more
PDS 456 is a nearby (z = 0.184), luminous (L bol ~ 1047 erg s-1) type I quasar. A deep 190 ks Suzaku observation in 2007 February revealed the complex, broadband X-ray spectrum of PDS 456. The Suzaku spectrum exhibits highly statistically significant absorption features near 9 keV in the quasar rest frame. We show …
Quantitative Measurements of Coronal Mass Ejection-Driven Shocks from LASCO Observations
Vourlidas, Angelos; Ontiveros, Veronica
In this paper, we demonstrate that coronal mass ejection (CME)-driven shocks can be detected in white light coronagraph images and in which properties such as the density compression ratio and shock direction can be measured. Also, their propagation direction can be deduced via simple modeling. We focused on CMEs during the ascending phase of sola…
Dynamical Masses of Early-Type Galaxies at z ~ 2: Are they Truly Superdense?
Cimatti, A.; Daddi, E.; Rodighiero, G. +11 more
We measured stellar velocity dispersions σ and derived dynamical masses of nine massive (M ≈ 1011 M sun) early-type galaxies (ETGs) from the Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS) sample at redshift 1.4 lsim z lsim 2.0. The σ are based on individual spectra for two galaxies at z ≈ 1.4 and on a stacked sp…
X-Ray Microlensing in RXJ1131-1231 and HE1104-1805
Kochanek, C. S.; Dai, X.; Chartas, G. +2 more
We present results from a monitoring campaign performed with the Chandra X-ray Observatory of the gravitationally lensed quasars RX J1131-1231 and HE 1104-1805. We detect significant X-ray variability in all images of both quasars. The flux variability detected in image A of RX J1131-1231 is of particular interest because of its high amplitude (a …
The Golden Standard Type Ia Supernova 2005cf: Observations from the Ultraviolet to the Near-Infrared Wavebands
Cenko, S. B.; Malkan, M. A.; Gal-Yam, A. +32 more
We present extensive photometry at ultraviolet (UV), optical, and near-infrared (NIR) wavelengths, as well as dense sampling of optical spectra, for the normal Type Ia supernova (SN Ia) 2005cf. The optical photometry, performed at eight different telescopes, shows a 1σ scatter of lsim0.03 mag after proper corrections for the instrument responses. …
Lyman Alpha Galaxies: Primitive, Dusty, or Evolved?
Finkelstein, Steven L.; Malhotra, Sangeeta; Grogin, Norman +1 more
We present stellar population modeling results for ten newly discovered Lyman alpha emitting galaxies (LAEs), as well as four previously known LAEs at z ~ 4.5 in the Chandra Deep Field-South. We fit stellar population models to these objects in order to specifically learn if there exists more than one class of LAE. Past observational and theoretic…