Search Publications
Merger-driven Fueling of Active Galactic Nuclei: Six Dual and Offset AGNs Discovered with Chandra and Hubble Space Telescope Observations
Greene, Jenny E.; Zakamska, Nadia L.; Comerford, Julia M. +4 more
Dual active galactic nuclei (AGNs) and offset AGNs are kpc-scale separation supermassive black holes pairs created during galaxy mergers, where both or one of the black holes are AGNs, respectively. These dual and offset AGNs are valuable probes of the link between mergers and AGNs but are challenging to identify. Here we present Chandra/ACIS obse…
The Most Luminous Galaxies Discovered by WISE
Tsai, Chao-Wei; Juneau, Stéphanie; Gelino, Christopher R. +25 more
We present 20 Wide-field Infrared Survey Explorer (WISE)-selected galaxies with bolometric luminosities Lbol > 1014 L⊙, including five with infrared luminosities LIR ≡ L(rest 8-1000 µm) > 1014 L⊙. These “extremely luminous infrared galaxies,” or ELIRGs, were d…
A Stubbornly Large Mass of Cold Dust in the Ejecta of Supernova 1987A
Ivison, R. J.; van Loon, J. Th.; Lundqvist, P. +33 more
We present new Herschel photometric and spectroscopic observations of Supernova 1987A, carried out in 2012. Our dedicated photometric measurements provide new 70 µm data and improved imaging quality at 100 and 160 µm compared to previous observations in 2010. Our Herschel spectra show only weak CO line emission, and provide an upper li…
New Constraints on the Faint End of the UV Luminosity Function at z ~ 7-8 Using the Gravitational Lensing of the Hubble Frontier Fields Cluster A2744
Richard, Johan; Schaerer, Daniel; Kneib, Jean-Paul +8 more
Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster A2744, we report the detection of 50 galaxy candidates at…
The Herschel Comprehensive (U)LIRG Emission Survey (HERCULES): CO Ladders, Fine Structure Lines, and Neutral Gas Cooling
Veilleux, S.; Sanders, D. B.; Isaak, K. G. +27 more
(Ultra) luminous infrared galaxies ((U)LIRGs) are objects characterized by their extreme infrared (8-1000 µm) luminosities (L LIRG > 1011 L ⊙ and L ULIRG > 1012 L ⊙). The Herschel Comprehensive ULIRG Emission Survey (PI: van der Werf) presents a representative flux-limit…
NuSTAR Spectroscopy of Multi-component X-Ray Reflection from NGC 1068
Hailey, Charles J.; Brandt, William N.; Comastri, Andrea +26 more
We report on high-energy X-ray observations of the Compton-thick Seyfert 2 galaxy NGC 1068 with NuSTAR, which provide the best constraints to date on its >10 keV spectral shape. The NuSTAR data are consistent with those from past and current instruments to within cross-calibration uncertainties, and we find no strong continuum or line variabili…
The SL2S Galaxy-scale Lens Sample. V. Dark Matter Halos and Stellar IMF of Massive Early-type Galaxies Out to Redshift 0.8
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +4 more
We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference me…
Gravitational Lens Modeling with Basis Sets
Amara, Adam; Refregier, Alexandre; Birrer, Simon
We present a strong lensing modeling technique based on versatile basis sets for the lens and source planes. Our method uses high performance Monte Carlo algorithms, allows for an adaptive build up of complexity, and bridges the gap between parametric and pixel based reconstruction methods. We apply our method to a Hubble Space Telescope image of …
A Massive, Distant Proto-cluster at z = 2.47 Caught in a Phase of Rapid Formation?
Sanders, D. B.; Treister, E.; Cooray, A. +6 more
Numerical simulations of cosmological structure formation show that the universe’s most massive clusters, and the galaxies living in those clusters, assemble rapidly at early times (2.5\lt z\lt 4). While more than 20 proto-clusters have been observed at z≳ 2 based on associations of 5-40 galaxies around rare sources, the observational evidence for…
Space Telescope and Optical Reverberation Mapping Project.I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope
Brandt, W. N.; Kriss, G. A.; Ely, J. +47 more
We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and broad emission lines, with amplitudes ranging from ∼3…