Eclipsing white dwarf binaries in <i>Gaia</i> and the Zwicky Transient Faaccility

Keller, Pascal M.; Breedt, E.; Hodgkin, S. T.; Belokurov, Vasily; Wild, J. F.; García-Soriano, Ignacio; Wise, Jacob L.

doi:10.1093/mnras/stab3293

Cited by 16 publications

(13 citation statements)

References 46 publications

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“…Three of these systems, J1644+2434, J1844+4857, and J2212+5347, were independently identified as eclipsing white dwarfs by Keller et al (2022) in a similar box least squares search for short-period white dwarf binaries in the ZTF DR3 archive. However, the authors did not provide any follow-up observations or detailed light curve analysis of these systems.…”

Section: Period Search Resultsmentioning

confidence: 99%

Four new deeply-eclipsing white dwarfs in ZTF

Kosakowski,

Kilic,

Brown

et al. 2022

Preprint

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We present the results of a search for deeply-eclipsing white dwarfs in the ZTF Data Release 4. We identify nine deeply-eclipsing white dwarf candidates, four of which we followed up with high-cadence photometry and spectroscopy. Three of these systems show total eclipses in the ZTF data and our follow-up APO 3.5-meter telescope observations. Even though the eclipse duration is consistent with sub-stellar companions, our analysis shows that all four systems contain a white dwarf with low-mass stellar companions of ∼ 0.1 𝑀 . We provide mass and radius constraints for both stars in each system based on our photometric and spectroscopic fitting. Finally, we present a list of 41 additional eclipsing WD+M candidates identified in a preliminary search of ZTF DR7, including 12 previously studied systems. We identify two new candidate short-period, eclipsing, white dwarf-brown dwarf binaries within our sample of 41 WD+M candidates based on PanSTARRS colors.

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Section: Period Search Resultsmentioning

confidence: 99%

Four new deeply-eclipsing white dwarfs in ZTF

Kosakowski,

Kilic,

Brown

et al. 2022

Preprint

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“…Among the ∼1000 WDs observed by the Kepler K2 mission (Howell et al 2014 ), only one new DWD was disco v ered (Hallakoun et al 2016 ;van Sluijs & Van Eylen 2018 , along with one known DWD). The Zwicky Transient Facility (ZTF; Bellm et al 2019 ;Graham et al 2019 ;Masci et al 2019 ), which has begun operating in 2018, shows promising results, with already ∼10 newly disco v ered ultra-compact DWDs (Burdge et al 2019(Burdge et al , 2020aCoughlin et al 2020 ;Keller et al 2022 ; and see also van Roestel et al 2021 for interacting DWDs). In the near future, large all-sky surv e ys such as Gaia (Gaia Collaboration 2016, 2018 and the Vera Rubin Observatory (LSST Science Collaboration 2009 ) have the potential to deliver up to a few hundred and a few thousand of ne w eclipsing DWDs, respecti vely (Eyer et al 2012 ;Korol et al 2017 ).…”

Section: The Search For Dwdsmentioning

confidence: 99%

Observationally driven Galactic double white dwarf population for LISA

Korol

Hallakoun

Toonen

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Realistic models of the Galactic double white dwarf (DWD) population are crucial for testing and quantitatively defining the science objectives of the Laser Interferometer Space Antenna (LISA), a future European Space Agency’s gravitational-wave observatory. In addition to numerous individually detectable DWDs, LISA will also detect an unresolved confusion foreground produced by the underlying Galactic population, which will affect the detectability of all LISA sources at frequencies below a few mHz. So far, the modelling of the DWD population for LISA has been based on binary population synthesis (BPS) techniques. The aim of this study is to construct an observationally-driven population. To achieve this, we employ a model developed by Maoz, Hallakoun & Badenes (2018) for the statistical analysis of the local DWD population using two complementary large, multi-epoch, spectroscopic samples: the Sloan Digital Sky Survey (SDSS), and the Supernova Ia Progenitor surveY (SPY). We calculate the number of LISA-detectable DWDs and the Galactic confusion foreground, based on their assumptions and results. We find that the observationally-driven estimates yield 1) 2 − 5 times more individually detectable DWDs than various BPS forecasts, and 2) a significantly different shape of the DWD confusion foreground. Both results have important implications for the LISA mission. A comparison between several variations to our underlying assumptions shows that our observationally-driven model is robust, and that the uncertainty on the total number of LISA-detectable DWDs is in the order of 20 per cent.

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“…The second method which is becoming increasingly more utilized recently relies on the synergy between the wide-angle variability surveys such as Kepler (Howell et al 2014) and the Zwicky Transient Facility (ZTF, Graham et al 2019;Bellm et al 2019), and Gaia (Perryman et al 2001;Gaia Collaboration et al 2018a). By inspecting the ZTF multi-epoch photometry of WDs selected from the Hertzsprung-Russell diagram the presence of close WD companions is established due to the characteristic narrow eclipses and/or ellipsoidal variations in the lightcurves (see Burdge et al 2019Burdge et al , 2020aCoughlin et al 2020;Keller et al 2022). In addition to the Gaiarelated selection effects (due to variations of the signal-to-noise of the astrometric measurement), the variability-based detections display a strong period-dependant efficiency evolution (see Korol et al 2017;Burdge et al 2020a;Keller et al 2022).…”

Section: Introductionmentioning

confidence: 99%

“…By inspecting the ZTF multi-epoch photometry of WDs selected from the Hertzsprung-Russell diagram the presence of close WD companions is established due to the characteristic narrow eclipses and/or ellipsoidal variations in the lightcurves (see Burdge et al 2019Burdge et al , 2020aCoughlin et al 2020;Keller et al 2022). In addition to the Gaiarelated selection effects (due to variations of the signal-to-noise of the astrometric measurement), the variability-based detections display a strong period-dependant efficiency evolution (see Korol et al 2017;Burdge et al 2020a;Keller et al 2022).…”

Section: Introductionmentioning

confidence: 99%

A gap in the double white dwarf separation distribution caused by the common-envelope evolution: astrometric evidence from Gaia

Korol,

Belokurov,

Toonen

2022

Preprint

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The trajectory of the center of light of an unresolved binary is different from that of its center of mass. Binary-induced stellar centroid wobbling can therefore be detected as an excess in the goodness-of-fit of the single-star astrometric model. We use reduced 𝜒 2 of the astrometric fit in the Gaia Early Data Release 3 to detect the likely unresolved double white dwarfs (DWDs). Using parallax-based distances we convert the excess of reduced 𝜒 2 into the amplitude of the centroid wobble 𝛿𝑎, which is proportional to the binary separation 𝑎. The measured 𝛿𝑎 distribution drops towards larger wobble amplitudes and shows a break around 𝛿𝑎 ≈ 0.2 where it steepens. The integral of the distribution yields DWD fraction of 6.5 ± 3.7 per cent in the range 0.01 < 𝑎 (au) < 2. Using synthetic models of the Galactic DWDs we demonstrate that the break in the 𝛿𝑎 distribution corresponds to one side of a deep gap in the DWD separation distribution at around 𝑎 ≈ 1 au. Model DWDs with separations less than several au shrink dramatically due to (al least one) common envelope phase, reshaping the original separation distribution, clearing a gap and creating a pile-up of systems with 𝑎 ≈ 0.01 au and 𝛿𝑎 < 0.01. Our models reproduce the overall shape of the observed 𝛿𝑎 distribution and its normalisation, however the predicted drop in the numbers of DWDs beyond the break is steeper than in the data.

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Eclipsing white dwarf binaries in Gaia and the Zwicky Transient Faaccility

Cited by 16 publications

References 46 publications

Four new deeply-eclipsing white dwarfs in ZTF

Four new deeply-eclipsing white dwarfs in ZTF

Observationally driven Galactic double white dwarf population for LISA

A gap in the double white dwarf separation distribution caused by the common-envelope evolution: astrometric evidence from Gaia

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