Search Publications
Distribution functions for magnetic fields on the quiet Sun
Stenflo, J. O.
The statistical properties of the highly structured magnetic field of the quiet Sun are best described in terms of distribution functions, in particular the probability density functions (PDF) for the flux densities and the angular distribution for the orientations of the field vector. They are needed to test the validity of various MHD simulation…
HST/NICMOS Paschen-α Survey of the Galactic Centre: Overview
Calzetti, D.; Muno, M. P.; Wang, Q. D. +6 more
We have recently carried out the first wide-field hydrogen Paschen-α line imaging survey of the Galactic Centre using the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument aboard the Hubble Space Telescope. The survey maps out a region of ) around the central supermassive black hole (Sgr A*) in the 1.87 and 1.90µm narrow…
MOIRCS Deep Survey. VI. Near-infrared Spectroscopy of K-Selected Star-forming Galaxies at z ~ 2
Koekemoer, Anton M.; Tanaka, Ichi; Yamada, Toru +13 more
We present the results of near-infrared multi-object spectroscopic observations for 37 BzK-color-selected star-forming galaxies conducted with MOIRCS on the Subaru Telescope. The sample is drawn from the Ks -band-selected catalog of the MOIRCS Deep Survey in the GOODS-N region. About half of our samples are selected from the publicly av…
Evidence of a fast evolution of the UV luminosity function beyond redshift 6 from a deep HAWK-I survey of the GOODS-S field
Maiolino, R.; Dickinson, M.; Giavalisco, M. +21 more
Aims: We perform a deep search for galaxies in the redshift range 6.5≤ z≤ 7.5, to measure the evolution of the number density of luminous galaxies in this redshift range and derive useful constraints on the evolution of their luminosity function.
Methods: We present here the first results of an ESO Large Programme, which exploits the uni…
Tidal Disruption, Global Mass Function, and Structural Parameter Evolution in Star Clusters
Vesperini, Enrico; Trenti, Michele; Pasquato, Mario
We present a unified picture for the evolution of star clusters on the two-body relaxation timescale. We use direct N-body simulations of star clusters in a galactic tidal field starting from different multimass King models, up to 10% of primordial binaries and up to N tot = 65, 536 particles. An additional run also includes a central I…
Hubble Space Telescope Far-ultraviolet Observations of Brightest Cluster Galaxies: The Role of Star Formation in Cooling Flows and BCG Evolution
Baum, Stefi A.; O'Dea, Christopher P.; Donahue, Megan +8 more
Quillen et al. and O'Dea et al. carried out a Spitzer study of a sample of 62 brightest cluster galaxies (BCGs) from the ROSAT brightest cluster sample, which were chosen based on their elevated Hα flux. We present Hubble Space Telescope Advanced Camera for Surveys far-ultraviolet (FUV) images of the Lyα and continuum emission of the luminous emis…
Relativistic disc reflection in the extreme NLS1 IRAS13224-3809
Brandt, W. N.; Ponti, G.; Fabian, A. C. +7 more
We present a spectral variability study of the XMM-Newton and Suzaku observations of one of the most extreme narrow-line Seyfert 1 galaxies, IRAS13224-3809. The X-ray spectrum is characterized by two main peculiar features: (i) a strong soft excess with a steep rise below about 1.3 keV and (ii) a deep drop in flux above 8.2 keV. Although absorptio…
On the origin of [NeII] 12.81 µm emission from pre-main sequence stars: Disks, jets, and accretion
Güdel, M.; Henning, Th.; van Boekel, R. +6 more
Context. Extreme-ultraviolet (EUV) and X-ray photons from classical T Tauri stars are powerful ionization and heating agents that drive disk chemistry, disk instabilities, and photoevaporative flows. The mid-infrared fine-structure line of [Ne ii] at 12.81 µm has been proposed to trace gas in disk surface layers heated and ionized by stellar…
A Spectroscopic Search for Leaking Lyman Continuum at z ~ 0.7
Ferguson, Henry C.; Giavalisco, Mauro; Brown, Thomas M. +11 more
We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z ~ 0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel on the Hubble Space Telescope. We report the detection of leaking Lyman continuum (LyC) radiation from an active galactic nu…
LoCuSS: connecting the dominance and shape of brightest cluster galaxies with the assembly history of massive clusters
Smith, Graham P.; Egami, E.; Dariush, A. +6 more
We study the luminosity gap, Δm12, between the first- and second-ranked galaxies in a sample of 59 massive (~1015Msolar) galaxy clusters, using data from the Hale Telescope, the Hubble Space Telescope, Chandra and Spitzer. We find that the Δm12 distribution, p(Δm12), is a declining function of…