Search Publications
The Taurus Spitzer Survey: New Candidate Taurus Members Selected Using Sensitive Mid-Infrared Photometry
Stapelfeldt, K. R.; Wolf, S.; Audard, M. +31 more
We report on the properties of pre-main-sequence objects in the Taurus molecular clouds as observed in seven mid- and far-infrared bands with the Spitzer Space Telescope. There are 215 previously identified members of the Taurus star-forming region in our ~44 deg2 map these members exhibit a range of Spitzer colors that we take to defin…
Bulgeless Giant Galaxies Challenge Our Picture of Galaxy Formation by Hierarchical Clustering
Kormendy, John; Bender, Ralf; Drory, Niv +1 more
To better understand the prevalence of bulgeless galaxies in the nearby field, we dissect giant Sc-Scd galaxies with Hubble Space Telescope (HST) photometry and Hobby-Eberly Telescope (HET) spectroscopy. We use the HET High Resolution Spectrograph (resolution R ≡ λ/FWHM ~= 15, 000) to measure stellar velocity dispersions in the nuclear star cluste…
CoRoT Reveals a Magnetic Activity Cycle in a Sun-Like Star
Metcalfe, Travis S.; García, Rafael A.; Mathur, Savita +4 more
The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solarlike oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and …
A Weak Lensing Study of X-ray Groups in the Cosmos Survey: Form and Evolution of the Mass-Luminosity Relation
Koekemoer, Anton M.; Elvis, Martin; Ellis, Richard S. +27 more
Measurements of X-ray scaling laws are critical for improving cosmological constraints derived with the halo mass function and for understanding the physical processes that govern the heating and cooling of the intracluster medium. In this paper, we use a sample of 206 X-ray-selected galaxy groups to investigate the scaling relation between X-ray …
Herschel-PACS spectroscopic diagnostics of local ULIRGs: Conditions and kinematics in Markarian 231
Lutz, D.; Genzel, R.; Poglitsch, A. +9 more
In this first paper on the results of our Herschel PACS survey of local ultra luminous infrared galaxies (ULIRGs), as part of our SHINING survey of local galaxies, we present far-infrared spectroscopy of Mrk 231, the most luminous of the local ULIRGs, and a type 1 broad absorption line AGN. For the first time in a ULIRG, all observed far-infrared …
Accurate fundamental parameters for 23 bright solar-type stars
Butler, R. P.; Carrier, F.; Lo Curto, G. +7 more
We combine results from interferometry, asteroseismology and spectroscopy to determine accurate fundamental parameters of 23 bright solar-type stars, from spectral type F5 to K2 and luminosity classes III-V. For some stars we can use direct techniques to determine the mass, radius, luminosity and effective temperature, and we compare with indirect…
Comprehensive Analysis of Coronal Mass Ejection Mass and Energy Properties Over a Full Solar Cycle
Howard, R. A.; Patsourakos, S.; Michalek, G. +3 more
The LASCO coronagraphs, in continuous operation since 1995, have observed the evolution of the solar corona and coronal mass ejections (CMEs) over a full solar cycle with high-quality images and regular cadence. This is the first time that such a data set becomes available and constitutes a unique resource for the study of CMEs. In this paper, we …
The Aquila prestellar core population revealed by Herschel
Olofsson, G.; Abergel, A.; Roussel, H. +37 more
The origin and possible universality of the stellar initial mass function (IMF) is a major issue in astrophysics. One of the main objectives of the Herschel Gould Belt Survey is to clarify the link between the prestellar core mass function (CMF) and the IMF. We present and discuss the core mass function derived from Herschel data for the large pop…
The Stellar Mass Density and Specific Star Formation Rate of the Universe at z ~ 7
Franx, Marijn; Labbé, Ivo; Kriek, Mariska +4 more
We use a robust sample of 11 z ~ 7 galaxies (z 850 dropouts) to estimate the stellar mass density (SMD) of the universe when it was only ~750 Myr old. We combine the very deep optical to near-infrared photometry from the Hubble Space Telescope Advanced Camera for Surveys and NICMOS cameras with mid-infrared Spitzer Infrared Array Camera…
A Correlation Between Stellar Activity and Hot Jupiter Emission Spectra
Knutson, Heather A.; Howard, Andrew W.; Isaacson, Howard
We present evidence for a correlation between the observed properties of hot Jupiter emission spectra and the activity levels of the host stars measured using Ca II H & K emission lines. We find that planets with dayside emission spectra that are well-described by standard one-dimensional atmosphere models with water in absorption (HD 189733, …