Search Publications
Found: the progenitors of AM CVn and supernovae .Ia
Hermes, J. J.; Bell, Keaton J.; Gianninas, A. +7 more
We present optical and X-ray observations of two tidally distorted, extremely low-mass white dwarfs (WDs) with massive companions. There is no evidence of neutron stars in our Chandra and XMM observations of these objects. SDSS J075141.18-014120.9 (J0751) is an eclipsing double WD binary containing a 0.19 M⊙ WD with a 0.97 M⊙…
Exploiting the full potential of photometric quasar surveys: optimal power spectra through blind mitigation of systematics
Leistedt, Boris; Peiris, Hiranya V.
We present optimal measurements of the angular power spectrum of the XDQSOz catalogue of photometric quasars from the Sloan Digital Sky Survey. These measurements rely on a quadratic maximum likelihood estimator that simultaneously measures the auto- and cross-power spectra of four redshift samples, and provides minimum-variance, unbiased estimate…
Chemistry and radiative transfer of water in cold, dense clouds
Caselli, Paola; Rawlings, Jonathan; Keto, Eric
The Herschel Space Observatory's recent detections of water vapour in the cold, dense cloud L1544 allow a direct comparison between observations and chemical models for oxygen species in conditions just before star formation. We explain a chemical model for gas-phase water, simplified for the limited number of reactions or processes that are activ…
Calibration of the Herschel SPIRE Fourier Transform Spectrometer
Valtchanov, I.; Spencer, L. D.; Wu, R. +21 more
The Herschel Spectral and Photometric REceiver (SPIRE) instrument consists of an imaging photometric camera and an imaging Fourier Transform Spectrometer (FTS), both operating over a frequency range of ∼450-1550 GHz. In this paper, we briefly review the FTS design, operation, and data reduction, and describe in detail the approach taken to relativ…
The age distribution of stellar clusters in M83.
Fouesneau, M.; Bastian, N.; Adamo, A. +2 more
In order to empirically determine the time-scale and environmental dependence of stellar cluster disruption, we have undertaken an analysis of the unprecedented multipointing (seven), multiwavelength (U, B, V, Hα, and I) Hubble Space Telescope imaging survey of the nearby, face-on spiral galaxy M83. The images are used to locate stellar clusters a…
The temperature dependence of the far-infrared-radio correlation in the Herschel-ATLAS
de Zotti, G.; Ibar, E.; Vaccari, M. +12 more
We use 10 387 galaxies from the Herschel Astrophysical TeraHertz Large Area Survey (H-ATLAS) to probe the far-infrared radio correlation (FIRC) of star-forming galaxies as a function of redshift, wavelength, and effective dust temperature. All of the sources in our 250 µm-selected sample have spectroscopic redshifts, as well as 1.4 GHz flux …
More Kronoseismology with Saturn's rings
Nicholson, P. D.; Hedman, M. M.
In a previous paper, we developed tools which allowed us to confirm that several of the waves in Saturn's rings were likely generated by resonances with fundamental sectoral normal modes inside Saturn itself. Here we use these same tools to examine eight additional waves that are probably generated by structures inside the planet. One of these wav…
The M 4 Core Project with HST - II. Multiple stellar populations at the bottom of the main sequence
Knigge, C.; van den Berg, M.; Anderson, J. +15 more
The M 4 Core Project with HST is designed to exploit the Hubble Space Telescope (HST) to investigate the central regions of M 4, the Globular Cluster closest to the Sun. In this paper we combine optical and near-infrared photometry to study multiple stellar populations in M 4. We detected two sequences of M-dwarfs containing ∼38 per cent (MSI…
The properties of the clumpy torus and BLR in the polar-scattered Seyfert 1 galaxy ESO 323-G77 through X-ray absorption variability
Bianchi, S.; Guainazzi, M.; Jiménez-Bailón, E. +8 more
We report results from multi-epoch (2006-2013) X-ray observations of the polar-scattered Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral variability from months to years timescales. The observed spectral variability is entirely due to variations of the column density of a neutral absorber towards the intrinsic nuclear continu…
The return to quiescence of Aql X-1 following the 2010 outburst
D'Avanzo, P.; Campana, S.; Mereghetti, S. +5 more
Aql X-1 is the most prolific low-mass X-ray binary transient hosting a neutron star. In this paper we focus on the return to quiescence following the 2010 outburst of the source. This decay was monitored thanks to 11 pointed observations taken with XMM-Newton, Chandra and Swift. The decay from outburst to quiescence is very fast, with an exponenti…