Search Publications
The number density of superdense early-type galaxies at 1 < z < 2 and the local cluster galaxies
Longhetti, M.; Gargiulo, A.; Saracco, P.
Many of the early-type galaxies (ETGs) observed so far at z > 1 turned out to have smaller radii with respect to that of a typical present day ETG with comparable mass. This has generated the conviction that in the past ETGs were more compact, hence denser, and that as a consequence, they should have increased their radius across the time to re…
Full lensing analysis of Abell 1703: comparison of independent lens-modelling techniques
Broadhurst, Tom; Zitrin, Adi; Umetsu, Keiichi +10 more
The inner mass profile of the relaxed cluster Abell 1703 is analysed by two very different strong-lensing techniques applied to the deep Advanced Camera for Surveys and the Wide Field Channel 3 imaging. Our parametric method has the accuracy required to reproduce many sets of multiple images, based on the assumption that mass approximately traces …
Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355
Manset, N.; Wade, G. A.; Marcolino, W. L. F. +5 more
We report the detection of a strong, organized magnetic field in the He-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. HR 7355 is both the most rapidly rotating known main-sequence magnet…
High-resolution X-ray spectroscopy and imaging of Mrk 573
Guainazzi, Matteo; Bianchi, Stefano; Piconcelli, Enrico +4 more
We present a detailed analysis of the XMM-Newton Reflection Grating Spectrometer (RGS) high-resolution X-ray spectra of the Seyfert 2 galaxy, Mrk 573. This analysis is complemented by the study of the Chandra image and its comparison to optical (Hubble Space Telescope) and radio (Very Large Array) data. The soft X-ray emission is mainly due to gas…
VLT-MAD observations of the core of 30 Doradus
Bastian, N.; Alves, J.; Mackey, A. D. +5 more
We present H- and Ks-band imaging of three fields at the centre of 30 Doradus (30 Dor) in the Large Magellanic Cloud, obtained as part of the Science Demonstration programme with the Multiconjugate Adaptive optics Demonstrator (MAD) at the Very Large Telescope. Strehl ratios of 15-30 per cent were achieved in the Ks band, yie…
Interstellar TiII in the Milky Way and Magellanic Clouds
Welty, Daniel E.; Crowther, Paul A.
We discuss several sets of TiII absorption-line data, which probe a variety of interstellar environments in our Galaxy and in the Magellanic Clouds. Comparisons of high-resolution [full width at half-maximum (FWHM) ~ 1.3-1.5kms-1] TiII spectra of Galactic targets with corresponding high-resolution spectra of NaI, KI and CaII reveal both…
X-ray spectral variability in the ultraluminous X-ray source Holmberg IX X-1
Done, C.; Roberts, T. P.; Mineshige, S. +1 more
We use XMM-Newton and Swift data to study a spectral variability in the ultraluminous X-ray source (ULX), Holmberg IX X-1. The source luminosity varies by a factor of 3-4, giving rise to corresponding spectral changes which are significant, but subtle, and not well tracked by a simple hardness ratio. Instead, we co-add the Swift data in intensity …
SDSS J094533.99+100950.1 - the remarkable weak emission line quasar
Hryniewicz, K.; Czerny, B.; Nikołajuk, M. +1 more
Weak emission line quasars are a rare and puzzling group of objects. In this paper, we present one more object of this class found in the Sloan Digital Sky Survey (SDSS). The quasar SDSS J094533.99+100950.1, lying at z = 1.66, has practically no CIV emission line, a red continuum very similar to the second steepest of the quasar composite spectra …
Bursting SN 1996cr's bubble: hydrodynamic and X-ray modelling of its circumstellar medium
Dwarkadas, V. V.; Dewey, D.; Bauer, F.
SN1996cr is one of the five closest supernovae (SNe) to explode in the past 30 yr. Due to its fortuitous location in the Circinus galaxy at ~3.7 Mpc, there is a wealth of recently acquired and serendipitous archival data available to piece together its evolution over the past decade, including a recent 485-ks Chandra high-energy transmission grati…
Observation and modelling of main-sequence star chromospheres - XIV. Rotation of dM1 stars
Houdebine, E. R.
We have measured v sin i for a selected sample of dM1-type stars. We give 114 measurements of v sin i for 88 different stars, and six upper detection limits. These are the first measurements of v sin i for most of the stars studied here. This represents the largest sample of v sin i measurements for M dwarfs at a given spectral type. For these mea…