Search Publications
Torus and Active Galactic Nucleus Properties of Nearby Seyfert Galaxies: Results from Fitting Infrared Spectral Energy Distributions and Spectroscopy
Alonso-Herrero, Almudena; Díaz-Santos, Tanio; Asensio Ramos, Andrés +9 more
We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions and ground-based high angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle i, the radial thickness of the torus Y, the angular …
Feedback in Luminous Obscured Quasars
Ho, Luis C.; Barth, Aaron J.; Greene, Jenny E. +1 more
We use spatially resolved long-slit spectroscopy from Magellan to investigate the extent, kinematics, and ionization structure in the narrow-line regions of 15 luminous, obscured quasars with z < 0.5. Increasing the dynamic range in luminosity by an order of magnitude, as well as improving the depth of existing observations by a similar factor,…
Very Strong Emission-line Galaxies in the WFC3 Infrared Spectroscopic Parallel Survey and Implications for High-redshift Galaxies
Scarlata, C.; Shim, H.; Malkan, M. +13 more
The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths…
A New Diagnostic of Active Galactic Nuclei: Revealing Highly Absorbed Systems at Redshift >0.3
Dickinson, Mark; Juneau, Stéphanie; Salim, Samir +1 more
We introduce the Mass-Excitation (MEx) diagnostic to identify active galactic nuclei (AGNs) in galaxies at intermediate redshift. In the absence of near-infrared spectroscopy, necessary for using traditional nebular line diagrams at z > 0.4, we demonstrate that combining [O III] λ5007/Hβ and stellar mass successfully distinguishes between star …
Far-infrared Line Deficits in Galaxies with Extreme L_{FIR}/M_{H_{2}} Ratios
Lutz, D.; Genzel, R.; Poglitsch, A. +13 more
We report initial results from the far-infrared fine structure line observations of a sample of 44 local starbursts, Seyfert galaxies, and infrared luminous galaxies obtained with the PACS spectrometer on board Herschel. We show that the ratio between the far-infrared luminosity and the molecular gas mass, {L_{FIR}/{M_{H_{2}}, is a much better pro…
The Yellow Supergiant Progenitor of the Type II Supernova 2011dh in M51
Sollerman, J.; Smartt, S. J.; Kotak, R. +11 more
We present the detection of the putative progenitor of the Type IIb SN 2011dh in archival pre-explosion Hubble Space Telescope images. Using post-explosion Adaptive Optics imaging with Gemini NIRI+ALTAIR, the position of the supernova (SN) in the pre-explosion images was determined to within 23 mas. The progenitor candidate is consistent with an F…
On the Evolution of the Molecular Gas Fraction of Star-Forming Galaxies
Smail, Ian; Moran, Sean M.; MacArthur, Lauren A. +3 more
We present IRAM Plateau de Bure interferometric detections of CO (J = 1 → 0) emission from a 24 µm-selected sample of star-forming galaxies at z = 0.4. The galaxies have polycyclic aromatic hydrocarbon 7.7 µm-derived star formation rates of SFR ~30-60 M sun yr-1 and stellar masses M sstarf ~ 1011
Globular Clusters in the Outer Galactic Halo: New Hubble Space Telescope/Advanced Camera for Surveys Imaging of Six Globular Clusters and the Galactic Globular Cluster Age-metallicity Relation
Anderson, Jay; Dotter, Aaron; Sarajedini, Ata
Color-magnitude diagrams (CMDs) derived from Hubble Space Telescope (HST) Advanced Camera for Surveys F606W, F814W photometry of six globular clusters (GCs) are presented. The six GCs form two loose groupings in Galactocentric distance (R GC): IC 4499, NGC 6426, and Ruprecht 106 at ~15-20 kpc and NGC 7006, Palomar 15, and Pyxis at ~40 k…
Observing Flux Rope Formation During the Impulsive Phase of a Solar Eruption
Liu, Y.; Cheng, X.; Ding, M. D. +1 more
Magnetic flux ropes are believed to be an important structural component of coronal mass ejections (CMEs). While there exists much observational evidence of flux ropes after the eruption, e.g., as seen in remote-sensing coronagraph images or in situ solar wind data, the direct observation of flux ropes during CME impulsive phase has been rare. In …
What Drives the Expansion of Giant H II Regions?: A Study of Stellar Feedback in 30 Doradus
Ramirez-Ruiz, Enrico; Prochaska, J. Xavier; Bolatto, Alberto D. +2 more
Observations show that star formation is an inefficient and slow process. This result can be attributed to the injection of energy and momentum by stars that prevents free-fall collapse of molecular clouds. The mechanism of this stellar feedback is debated theoretically; possible sources of pressure include the classical warm H II gas, the hot gas…