Search Publications
The Spectral Energy Distributions of z ~ 8 Galaxies from the IRAC Ultra Deep Fields: Emission Lines, Stellar Masses, and Specific Star Formation Rates at 650 Myr
Trenti, M.; Oesch, P. A.; Carollo, C. M. +8 more
Using new ultradeep Spitzer/InfraRed Array Camera (IRAC) photometry from the IRAC Ultra Deep Field program, we investigate the stellar populations of a sample of 63 Y-dropout galaxy candidates at z ~ 8, only 650 Myr after the big bang. The sources are selected from HST/ACS+WFC3/IR data over the Hubble Ultra Deep Field (HUDF), two HUDF parallel fie…
Suzaku observations of `bare' active galactic nuclei
Fabian, A. C.; Nardini, E.; Reis, R. C. +2 more
We present an X-ray spectral analysis of a large sample of 25 `bare' active galactic nuclei (AGN), sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from relativistic disc reflection and examining the implications of this interpretation for the intrinsic spect…
Recent variability of the solar spectral irradiance and its impact on climate modelling
Weber, M.; Solanki, S. K.; Schmutz, W. +12 more
The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and C…
Probing the Dawn of Galaxies at z ~ 9-12: New Constraints from HUDF12/XDF and CANDELS data
Trenti, M.; Oesch, P. A.; Stiavelli, M. +7 more
We present a comprehensive analysis of z > 8 galaxies based on ultra-deep WFC3/IR data. We exploit all the WFC3/IR imaging over the Hubble Ultra-Deep Field from the HUDF09 and the new HUDF12 program, in addition to the HUDF09 parallel field data, as well as wider area imaging over GOODS-South. Galaxies are selected based on the Lyman break tech…
The Density Profiles of Massive, Relaxed Galaxy Clusters. I. The Total Density Over Three Decades in Radius
Richard, Johan; Treu, Tommaso; Ellis, Richard S. +4 more
Clusters of galaxies are excellent locations to probe the distribution of baryons and dark matter (DM) over a wide range of scales. We study a sample of seven massive (M 200 = 0.4-2 × 1015 M ⊙), relaxed galaxy clusters with centrally located brightest cluster galaxies (BCGs) at z = 0.2-0.3. Using the observational …
A lower bound on the mass of cold thermal dark matter from Planck
Dolan, Matthew J.; Bœhm, Céline; McCabe, Christopher
We show that the new measurement of the effective number of neutrinos (Neff) by the Planck satellite can be used to set a robust lower bound on the mass of cold thermal dark matter of Script O(MeV). Our limit applies if the dark matter remains in thermal equilibrium by coupling to electrons and photons or through interactions with neutr…
Suppression of star formation in the galaxy NGC 253 by a starburst-driven molecular wind
Ott, Jürgen; Warren, Steven R.; Bolatto, Alberto D. +9 more
The under-abundance of very massive galaxies in the Universe is frequently attributed to the effect of galactic winds. Although ionized galactic winds are readily observable, most of the expelled mass (that is, the total mass flowing out from the nuclear region) is likely to be in atomic and molecular phases that are cooler than the ionized phases…
Measurement of the Radius of Neutron Stars with High Signal-to-noise Quiescent Low-mass X-Ray Binaries in Globular Clusters
Guillot, Sebastien; Webb, Natalie A.; Servillat, Mathieu +1 more
This paper presents the measurement of the neutron star (NS) radius using the thermal spectra from quiescent low-mass X-ray binaries (qLMXBs) inside globular clusters (GCs). Recent observations of NSs have presented evidence that cold ultra dense matter—present in the core of NSs—is best described by "normal matter" equations of state (EoSs). Such…
ALMA Redshifts of Millimeter-selected Galaxies from the SPT Survey: The Redshift Distribution of Dusty Star-forming Galaxies
Gladders, M. D.; Menten, K. M.; Bock, J. J. +64 more
Using the Atacama Large Millimeter/submillimeter Array, we have conducted a blind redshift survey in the 3 mm atmospheric transmission window for 26 strongly lensed dusty star-forming galaxies (DSFGs) selected with the South Pole Telescope. The sources were selected to have S 1.4 mm > 20 mJy and a dust-like spectrum and, to remove lo…
A rapidly spinning supermassive black hole at the centre of NGC 1365
Harrison, F. A.; Zhang, W. W.; Nardini, E. +9 more
Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape…