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Papers by Linda Schmidtobreick

Abstract. In this review, I give a summary of the history of our understanding of gravitational w... more Abstract. In this review, I give a summary of the history of our understanding of gravitational waves and how compact binaries were used to transform their status from mathematical artefact to physical reality. I also describe the types of compact (stellar) binaries that LISA will observe as soon as it is switched on. Finally, the status and near future of LIGO, Virgo and GEO are discussed, as well as the expected detection rates for the Advanced detectors, and the accuracies with which binary parameters can be determined when BH/NS inspirals are detected. 1.

Received date/Accepted date Aims. We performed a detailed spectroscopic analysis of the dwarf nov... more Received date/Accepted date Aims. We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines. Methods. We obtained high-resolution echelle spectroscopic data at ESO’s NTT with EMMI, covering the spectral range of 4000– 7500Å. The analysis was performed using standard IRAF tools. The indirect imaging technique of Doppler tomography was applied, in order to map the accretion disc and distinguish between the different emission sources. Results. The spectra are characterised by strong Balmer emission, together with lines of Hei and the iron triplet Feii 42. All lines are double-peaked, but the blue-to-red peak strength and central absorption depth vary. The primary’s velocity was found to be 84.9 km s −1. The spectrograms of the emission lines reveal the prograde rotation of a disc-like emitting region and, for the Balmer and Hei lines, an enhancement of ...

Abstract. In this review, I give a summary of the history of our understanding of gravitational w... more Abstract. In this review, I give a summary of the history of our understanding of gravitational waves and how compact binaries were used to transform their status from mathematical artefact to physical reality. I also describe the types of compact (stellar) binaries that LISA will observe as soon as it is switched on. Finally, the status and near future of LIGO, Virgo and GEO are discussed, as well as the expected detection rates for the Advanced detectors, and the accuracies with which binary parameters can be determined when BH/NS inspirals are detected.

The K-band Multi-Object Spectrograph (KMOS) is one of the secondgeneration instruments at the VLT... more The K-band Multi-Object Spectrograph (KMOS) is one of the secondgeneration instruments at the VLT, and has been operating for five years. To celebrate this anniversary this workshop brought together astronomers to present scientific results from KMOS and complementary instruments. The topics ranged from star formation in the Galactic centre, to stellar populations in globular clusters, to galaxy formation and evolution at various redshifts, and feedback from active galactic nuclei (AGN). Another goal of the workshop was to assess the impact of KMOS on its core science goals and to develop new strategies and programmes, also in light of future integral field unit (IFU) instruments. About 60 researchers from the astronomical community and members of the Instrument Operations Team participated in the workshop and discussed the above topics; these discussions served to identify the highest priority improvements that could increase the scientific return of KMOS in the future.

SW Sextantis stars are a relatively large group of cataclysmic variables (CVs) whose properties c... more SW Sextantis stars are a relatively large group of cataclysmic variables (CVs) whose properties contradict all predictions made by the current CV evolution theories. Very little is known about the properties of their accreting white dwarfs and their donor stars, as the stellar components are usually outshone by an extremely bright accretion flow. Consequently, a proper assesment of their evolutionary state is illusionary. We are monitoring the brightness of a number of SW Sex stars and request here Gemini/GMOS-N ToO time to obtain orbital phase-resolved spectroscopy if one of them enters a low state, since this is the only opportunity for studying the stellar components individually. These data will be used to accurately measure the mass ratio of the system which, combined with the orbital inclination derived from modelling of either the disc eclipses in the high state or the ellipsoidal modulation in the low state, will eventually provide the first detailed system parameters for any SW Sex star.

The Messenger, 2012

Planetary nebulae (PNe) are amongst the most complex and varied of celestial objects, displaying ... more Planetary nebulae (PNe) are amongst the most complex and varied of celestial objects, displaying a wide range of shapes and colours that are difficult to explain. Using the FORS2 instrument — mostly when no other observations can be performed — we have started to build up a homogeneous morphological catalogue of deep two-colour narrowband images of newly discovered PNe. The catalogue will be public and should soon become an invaluable tool for the community.

Here we report the recovery of the binary underlying the classical nova of 11 March 1437 A.D. who... more Here we report the recovery of the binary underlying the classical nova of 11 March 1437 A.D. whose age is independently confirmed by proper motion-dating, and show that in the 20th century it exhibits dwarf nova eruptions. The four oldest recovered classical novae are now all dwarf novae. Taken together they strongly suggest that mass transfer rates decrease by an order of magnitude or more in the centuries after a classical nova event, greatly slowing the evolution, and lengthening the lifetimes of these explosive binary stars.

Close interacting binaries such as cataclysmic variables from from detached binary stars that go ... more Close interacting binaries such as cataclysmic variables from from detached binary stars that go through a common envelope phase as the more massive star expands. During this phase the binary separation shrinks rapidly due to friction, so that the resulting post-common-envelope binary (PCEB) emerges with an orbital period in the order of one to a few days. Angular-momentum-loss mechanisms further reduce the orbital period eventually down to a semi-detached configuration, where the late-type main-sequence secondary star transfers matter to the white dwarf primary via Roche-lobe overflow. Recently, we found the PCEB LTT 560 to present an Hα emission line that consists of two components, one from each stellar component (Tappert et al. 2007, 2011). Apparently, in this still detached system, wind accretion takes place at such a rate that it induces emission. LTT 560 inhabits a cool (∼8000 K), non-magnetic white dwarf and an M5.5V secondary, that complete one orbit in 3.54 h. Apart from t...

The Messenger, 2020

The historical context of astronomical observatories in Chile was given by Bárbara Silva from the... more The historical context of astronomical observatories in Chile was given by Bárbara Silva from the Pontificia Universidad Católica de Chile. The earliest astronomical site explorations by US astronomers were carried out around the end of the 19th and the beginning of the 20th centuries and identified the Atacama Desert around Copiapó and north of La Serena as potentially excellent sites for nighttime observations. The International Geophysical Year in 1958 brought the Chilean sites to the attention of American astronomers again and site explorations by Jürgen Stock — originally for the University of Chicago and later for the Association of Universities for Research in Astronomy (AURA) — identified mountains around Vicuña as possible observatory sites. After the US National Science Foundation selected Cerro Tololo as their southern station, ESO also became interested (through Stock’s former advisor Otto Heckmann, then ESO Director General). This was a rather abrupt change from the ori...

Abstract. In this review, I give a summary of the history of our understanding of gravitational w... more Abstract. In this review, I give a summary of the history of our understanding of gravitational waves and how compact binaries were used to transform their status from mathematical artefact to physical reality. I also describe the types of compact (stellar) binaries that LISA will observe as soon as it is switched on. Finally, the status and near future of LIGO, Virgo and GEO are discussed, as well as the expected detection rates for the Advanced detectors, and the accuracies with which binary parameters can be determined when BH/NS inspirals are detected. 1.

Received date/Accepted date Aims. We performed a detailed spectroscopic analysis of the dwarf nov... more Received date/Accepted date Aims. We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines. Methods. We obtained high-resolution echelle spectroscopic data at ESO’s NTT with EMMI, covering the spectral range of 4000– 7500Å. The analysis was performed using standard IRAF tools. The indirect imaging technique of Doppler tomography was applied, in order to map the accretion disc and distinguish between the different emission sources. Results. The spectra are characterised by strong Balmer emission, together with lines of Hei and the iron triplet Feii 42. All lines are double-peaked, but the blue-to-red peak strength and central absorption depth vary. The primary’s velocity was found to be 84.9 km s −1. The spectrograms of the emission lines reveal the prograde rotation of a disc-like emitting region and, for the Balmer and Hei lines, an enhancement of ...

Abstract. In this review, I give a summary of the history of our understanding of gravitational w... more Abstract. In this review, I give a summary of the history of our understanding of gravitational waves and how compact binaries were used to transform their status from mathematical artefact to physical reality. I also describe the types of compact (stellar) binaries that LISA will observe as soon as it is switched on. Finally, the status and near future of LIGO, Virgo and GEO are discussed, as well as the expected detection rates for the Advanced detectors, and the accuracies with which binary parameters can be determined when BH/NS inspirals are detected.

The K-band Multi-Object Spectrograph (KMOS) is one of the secondgeneration instruments at the VLT... more The K-band Multi-Object Spectrograph (KMOS) is one of the secondgeneration instruments at the VLT, and has been operating for five years. To celebrate this anniversary this workshop brought together astronomers to present scientific results from KMOS and complementary instruments. The topics ranged from star formation in the Galactic centre, to stellar populations in globular clusters, to galaxy formation and evolution at various redshifts, and feedback from active galactic nuclei (AGN). Another goal of the workshop was to assess the impact of KMOS on its core science goals and to develop new strategies and programmes, also in light of future integral field unit (IFU) instruments. About 60 researchers from the astronomical community and members of the Instrument Operations Team participated in the workshop and discussed the above topics; these discussions served to identify the highest priority improvements that could increase the scientific return of KMOS in the future.

SW Sextantis stars are a relatively large group of cataclysmic variables (CVs) whose properties c... more SW Sextantis stars are a relatively large group of cataclysmic variables (CVs) whose properties contradict all predictions made by the current CV evolution theories. Very little is known about the properties of their accreting white dwarfs and their donor stars, as the stellar components are usually outshone by an extremely bright accretion flow. Consequently, a proper assesment of their evolutionary state is illusionary. We are monitoring the brightness of a number of SW Sex stars and request here Gemini/GMOS-N ToO time to obtain orbital phase-resolved spectroscopy if one of them enters a low state, since this is the only opportunity for studying the stellar components individually. These data will be used to accurately measure the mass ratio of the system which, combined with the orbital inclination derived from modelling of either the disc eclipses in the high state or the ellipsoidal modulation in the low state, will eventually provide the first detailed system parameters for any SW Sex star.

The Messenger, 2012

Planetary nebulae (PNe) are amongst the most complex and varied of celestial objects, displaying ... more Planetary nebulae (PNe) are amongst the most complex and varied of celestial objects, displaying a wide range of shapes and colours that are difficult to explain. Using the FORS2 instrument — mostly when no other observations can be performed — we have started to build up a homogeneous morphological catalogue of deep two-colour narrowband images of newly discovered PNe. The catalogue will be public and should soon become an invaluable tool for the community.

Here we report the recovery of the binary underlying the classical nova of 11 March 1437 A.D. who... more Here we report the recovery of the binary underlying the classical nova of 11 March 1437 A.D. whose age is independently confirmed by proper motion-dating, and show that in the 20th century it exhibits dwarf nova eruptions. The four oldest recovered classical novae are now all dwarf novae. Taken together they strongly suggest that mass transfer rates decrease by an order of magnitude or more in the centuries after a classical nova event, greatly slowing the evolution, and lengthening the lifetimes of these explosive binary stars.

Close interacting binaries such as cataclysmic variables from from detached binary stars that go ... more Close interacting binaries such as cataclysmic variables from from detached binary stars that go through a common envelope phase as the more massive star expands. During this phase the binary separation shrinks rapidly due to friction, so that the resulting post-common-envelope binary (PCEB) emerges with an orbital period in the order of one to a few days. Angular-momentum-loss mechanisms further reduce the orbital period eventually down to a semi-detached configuration, where the late-type main-sequence secondary star transfers matter to the white dwarf primary via Roche-lobe overflow. Recently, we found the PCEB LTT 560 to present an Hα emission line that consists of two components, one from each stellar component (Tappert et al. 2007, 2011). Apparently, in this still detached system, wind accretion takes place at such a rate that it induces emission. LTT 560 inhabits a cool (∼8000 K), non-magnetic white dwarf and an M5.5V secondary, that complete one orbit in 3.54 h. Apart from t...

The Messenger, 2020

The historical context of astronomical observatories in Chile was given by Bárbara Silva from the... more The historical context of astronomical observatories in Chile was given by Bárbara Silva from the Pontificia Universidad Católica de Chile. The earliest astronomical site explorations by US astronomers were carried out around the end of the 19th and the beginning of the 20th centuries and identified the Atacama Desert around Copiapó and north of La Serena as potentially excellent sites for nighttime observations. The International Geophysical Year in 1958 brought the Chilean sites to the attention of American astronomers again and site explorations by Jürgen Stock — originally for the University of Chicago and later for the Association of Universities for Research in Astronomy (AURA) — identified mountains around Vicuña as possible observatory sites. After the US National Science Foundation selected Cerro Tololo as their southern station, ESO also became interested (through Stock’s former advisor Otto Heckmann, then ESO Director General). This was a rather abrupt change from the ori...