Search Publications
Covariance of lucky images: performance analysis
Ginski, C.; Mugrauer, M.; Seeliger, M. +5 more
The covariance of ground-based lucky images is a robust and easy-to-use algorithm that allows us to detect faint companions surrounding a host star. In this paper, we analyse the relevance of the number of processed frames, the frames' quality, the atmosphere conditions and the detection noise on the companion detectability. This analysis has been…
First hard X-ray detection and broad-band X-ray study of the unidentified transient AX J1949.8+2534
Masetti, N.; Sidoli, L.; Bird, A. J. +3 more
We present the results from INTEGRAL and Swift/XRT observations of the hitherto poorly studied unidentified X-ray transient AX J1949.8+2534, and on archival multiwavelength observations of field objects. Bright hard X-ray outbursts have been discovered above 20 keV for the first time, the measured duty cycle and dynamic range are of the order of ∼…
HST Hα grism spectroscopy of ROLES: a flatter low-mass slope for the z ∼ 1 SSFR-mass relation
Glazebrook, Karl; Skelton, Rosalind E.; Balogh, Michael L. +4 more
We present measurements of star formation rates (SFRs) for dwarf galaxies (M* ∼ 108.5 M_{⊙}) at z ∼ 1 using near-infrared slitless spectroscopy from the Hubble Space Telescope (HST) by targeting and measuring the luminosity of the Hα emission line. Our sample is derived from the Redshift One LDSS3 Emission Line Survey (ROLES)…
The interstellar medium in Andromeda's dwarf spheroidal galaxies - II. Multiphase gas content and ISM conditions
Wilson, Christine D.; De Looze, Ilse; Baes, Maarten +11 more
We make an inventory of the interstellar medium material in three low-metallicity dwarf spheroidal galaxies of the Local Group (NGC 147, NGC 185 and NGC 205). Ancillary H I, CO, Spitzer Infrared Spectrograph spectra, Hα and X-ray observations are combined to trace the atomic, cold and warm molecular, ionized and hot gas phases. We present new Nobe…
A study of a coronal hole associated with a large filament eruption
Gutiérrez, Heidy; Taliashvili, Lela; Lazarian, Alexandre +1 more
We report the results of a detailed study of an equatorial coronal hole and a dimming region related to the eruptions of a nearby large filament and subsequent coronal mass ejections (CMEs). The dynamic eruptions of the filament and the associated CMEs are probably related to the magnetic reconnection involving the magnetic field lines at the fila…
XMM-Newton and NuSTAR joint observations of Mrk 915: a deep look into the X-ray properties
Campana, S.; Moretti, A.; Vignali, C. +5 more
We report on the X-ray monitoring programme (covering slightly more than 11 d) carried out jointly by XMM-Newton and NuSTAR on the intermediate Seyfert galaxy Mrk 915. The light curves extracted in different energy ranges show a variation in intensity but not a significant change in the spectral shape. The X-ray spectra reveal the presence of a tw…
An astrometric and spectroscopic study of the δ Scuti variable HD 21190 and its wide companion CPD -83° 64B
Ilyin, I.; Niemczura, E.; Hubrig, S. +4 more
Although pulsations of δ Scuti type are not expected among Ap stars from a theoretical point of view, previous observations of the known δ Scuti star HD 21190 indicated a spectral classification F2 III SrEuSi:, making it the most evolved Ap star known. Our atmospheric chemical analysis based on recent High Accuracy Radial velocity Planet Searcher …
CXO J004318.8+412016, a steady supersoft X-ray source in M 31
Luna, G. J. M.; Della Valle, M.; de Martino, D. +15 more
We obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Å. The continuum energy distribution and the spectral characteristics demonstrate the presence of a red giant of K or …
On the methanol emission detection in the TW Hya disc: the role of grain surface chemistry and non-LTE excitation
Henning, Th.; Sobolev, A. M.; Semenov, D. A. +3 more
The recent detection of gas-phase methanol (CH3OH) lines in the disc of TW Hya by Walsh et al. provided the first observational constraints on the complex O-bearing organic content in protoplanetary discs. The emission has a ring-like morphology, with a peak at ∼30-50 au and an inferred column density of ∼3-6 × 1012 cm-2…
A Multiply-Imaged z ∼ 6.3 Lyman Alpha Emitter candidate behind Abell 2261
Östlin, Göran; Melinder, Jens; Klessen, Ralf S. +6 more
While the Lyman α (Ly α) emission line serves as an important tool in the study of galaxies at z ≲ 6, finding Ly α emitters (LAE) at significantly higher redshifts has been more challenging, probably because of the increasing neutrality of the intergalactic medium above z ∼ 6. Galaxies with extremely high rest-frame Ly α equivalent widths, EW(Ly α…