Search Publications
Ultrafast outflows in radio-loud active galactic nuclei
Cappi, M.; Guainazzi, M.; Tombesi, F. +5 more
Recent X-ray observations show absorbing winds with velocities up to mildly relativistic values of the order of ∼0.1c in a limited sample of six broad-line radio galaxies. They are observed as blueshifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultrafast outflows (UFOs) reported in Seyferts and quasars. In this work we extend the se…
Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert galaxies - I. A global view and frequency of occurrence of warm absorbers.
Dewangan, Gulab C.; Guainazzi, Matteo; Laha, Sibasish +2 more
We present results from a homogeneous analysis of the broad-band 0.3-10 keV CCD resolution as well as of the soft X-ray high-resolution grating spectra of a hard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton. Our goal is to characterize warm absorbers (WAs) along the line of sight to the active nucleus. We significantly…
Ultra-faint Ultraviolet Galaxies at z ~ 2 behind the Lensing Cluster A1689: The Luminosity Function, Dust Extinction, and Star Formation Rate Density
Teplitz, Harry I.; Richard, Johan; Scarlata, Claudia +8 more
We have obtained deep ultraviolet imaging of the lensing cluster A1689 with the WFC3/UVIS camera onboard the Hubble Space Telescope in the F275W (30 orbits) and F336W (4 orbits) filters. These images are used to identify z ~ 2 star-forming galaxies via their Lyman break, in the same manner that galaxies are typically selected at z >= 3. Because…
Evidence for Particle Re-acceleration in the Radio Relic in the Galaxy Cluster PLCKG287.0+32.9
Nonino, M.; van Weeren, R. J.; Röttgering, H. J. A. +5 more
Radio relics are diffuse radio sources observed in galaxy clusters, probably produced by shock acceleration during cluster-cluster mergers. Their large size, of the order of 1 Mpc, indicates that the emitting electrons need to be (re)accelerated locally. The usually invoked diffusive shock acceleration models have been challenged by recent observa…
Abundant Molecular Gas and Inefficient Star Formation in Intracluster Regions: Ram Pressure Stripped Tail of the Norma Galaxy ESO137-001
Combes, Françoise; Sun, Ming; Jáchym, Pavel +2 more
For the first time, we reveal large amounts of cold molecular gas in a ram-pressure-stripped tail, out to a large "intracluster" distance from the galaxy. With the Actama Pathfinder EXperiment (APEX) telescope, we have detected 12CO(2-1) emission corresponding to more than 109 M ⊙ of H2 in three Hα brigh…
The Besançon Galaxy model renewed. I. Constraints on the local star formation history from Tycho data
Luri, X.; Figueras, F.; Haywood, M. +2 more
Context. The understanding of Galaxy evolution can be facilitated by the use of population synthesis models, which allows us to test hypotheses on the star formation history, star evolution, and chemical and dynamical evolution of the Galaxy.
Aims: The new version of the Besançon Galaxy model (BGM) aims to provide a more flexible and powerful…
The Reflection Component from Cygnus X-1 in the Soft State Measured by NuSTAR and Suzaku
Hailey, Charles J.; Fürst, Felix; Pottschmidt, Katja +21 more
The black hole binary Cygnus X-1 was observed in late 2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ~1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power law, and reflection components along with absorption from highly ionized material in the sys…
Slow Evolution of the Specific Star Formation Rate at z > 2: The Impact of Dust, Emission Lines, and a Rising Star Formation History
Franx, Marijn; Labbé, Ivo; Oesch, Pascal +4 more
We measure the evolution of the specific star formation rate (sSFR = SFR/M stellar) between redshift 4 and 6 to assess the reported "constant" sSFR at z > 2. We derive stellar masses and star formation rates (SFRs) for a large sample of 750 z ~ 4-6 galaxies in the GOODS-S field by fitting stellar population models to their spectral e…
Confirmation via the Continuum-fitting Method that the Spin of the Black Hole in Cygnus X-1 Is Extreme
Steiner, James F.; Remillard, Ronald A.; McClintock, Jeffrey E. +6 more
In Gou et al., we reported that the black hole primary in the X-ray binary Cygnus X-1 is a near-extreme Kerr black hole with a spin parameter a * > 0.95 (3σ). We confirm this result while setting a new and more stringent limit: a * > 0.983 at the 3σ (99.7%) confidence level. The earlier work, which was based on an analy…
The Gaia FGK benchmark stars. High resolution spectral library
Soubiran, C.; Heiter, U.; Blanco-Cuaresma, S. +1 more
Context. An increasing number of high-resolution stellar spectra is available today thanks to many past and ongoing spectroscopic surveys. Consequently, numerous methods have been developed to perform an automatic spectral analysis on a massive amount of data. When reviewing published results, biases arise and they need to be addressed and minimiz…