Search Publications
A Young Massive Stellar Population around the Intermediate-mass Black Hole ESO 243-49 HLX-1
Maccarone, T. J.; Knigge, C.; Farrell, S. A. +9 more
We present Hubble Space Telescope and simultaneous Swift X-ray Telescope observations of the strongest candidate intermediate-mass black hole (IMBH) ESO 243-49 HLX-1. Fitting the spectral energy distribution from X-ray to near-infrared wavelengths showed that the broadband spectrum is not consistent with simple and irradiated disk models, but is w…
3D-HST Grism Spectroscopy of a Gravitationally Lensed, Low-metallicity Starburst Galaxy at z = 1.847
Schmidt, Kasper B.; van Dokkum, Pieter G.; Franx, Marijn +17 more
We present Hubble Space Telescope (HST) imaging and spectroscopy of the gravitational lens SL2SJ02176-0513, a cusp arc at z = 1.847. The UV continuum of the lensed galaxy is very blue, which is seemingly at odds with its redder optical colors. The 3D-HST WFC3/G141 near-infrared spectrum of the lens reveals the source of this discrepancy to be extr…
Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium Abundance
Anderson, J.; Milone, A. P.; Bedin, L. R. +6 more
We revisit the problem of the split main sequence (MS) of the globular cluster ω Centauri, and report the results of two-epoch Hubble Space Telescope observations of an outer field, for which proper motions give us a pure sample of cluster members, and an improved separation of the two branches of the MS. Using a new set of stellar models covering…
Molecular line survey of the high-mass star-forming region NGC 6334I with Herschel/HIFI and the Submillimeter Array
Ceccarelli, C.; Comito, C.; Schilke, P. +7 more
Aims: We aim at deriving the molecular abundances and temperatures of the hot molecular cores in the high-mass star-forming region NGC 6334I and consequently deriving their physical and astrochemical conditions.
Methods: In the framework of the Herschel guaranteed time key program CHESS (Chemical HErschel Surveys of Star forming regions)…
Polar Field Reversal Observations with Hinode
Ishikawa, R.; Tsuneta, S.; Orozco Suárez, D. +3 more
We have been monitoring yearly variation in the Sun's polar magnetic fields with the Solar Optical Telescope aboard Hinode to record their evolution and expected reversal near the solar maximum. All magnetic patches in the magnetic flux maps are automatically identified to obtain the number density and magnetic flux density as a function of the to…
On the influence of the companion star in Eta Carinae: 2D radiative transfer modelling of the ultraviolet and optical spectra
Hillier, D. John; Weigelt, Gerd; Madura, Thomas I. +1 more
We present two-dimensional (2D) radiative transfer modelling of the Eta Carinae binary system accounting for the presence of a wind-wind collision (WWC) cavity carved in the optically thick wind of the primary star. By comparing synthetic line profiles with spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph near …
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra
Done, Chris; Ward, Martin; Jin, Chichuan
In this second paper in a series of three, we study the properties of the various emission features and underlying continuum in the optical spectra of type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We introduce the use of the 'correlation spectrum technique' (CST) for the first time. We use this t…
Large-scale Motions in the Perseus Galaxy Cluster
Simionescu, A.; Fabian, A. C.; Allen, S. W. +6 more
By combining large-scale mosaics of ROSAT PSPC, XMM-Newton, and Suzaku X-ray observations, we present evidence for large-scale motions in the intracluster medium of the nearby, X-ray bright Perseus Cluster. These motions are suggested by several alternating and interleaved X-ray bright, low-temperature, low-entropy arcs located along the east-west…
Transient dust in warm debris disks. Detection of Fe-rich olivine grains
Mutschke, H.; Ábrahám, P.; Henning, Th. +4 more
Context. Debris disks trace remnant reservoirs of leftover planetesimals in planetary systems. In the past years, a handful of "warm" debris disks have been discovered in which emission in excess starts in the mid-infrared. An interesting subset of these warm debris disks shows emission features in mid-infrared spectra, which points towards the pr…
A DEBRIS disk around the planet hosting M-star GJ 581 spatially resolved with Herschel
Duchêne, G.; Dent, W. R. F.; Bryden, G. +17 more
Debris disks have been found primarily around intermediate and solar mass stars (spectral types A-K) but rarely around low mass M-type stars. We have spatially resolved a debris disk around the remarkable M3-type star GJ 581 hosting multiple planets using deep PACS images at 70, 100 and 160 µm as part of the DEBRIS Program on the Herschel Sp…