Recovering variable stars in large surveys: EAup Algol-type class in the Catalina Survey

Carmo, Ana Paula do; Lopes, C. E. Ferreira; Παπαγεωργίου, Αθανάσιος; Jablonski, F.; Rodrigues, C. V.; Drake, A. J.; Cross, N. J. G.; Catelan, M.

doi:10.1093/mnras/staa2518

Cited by 9 publications

(7 citation statements)

References 74 publications

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“…Note the amplitude of variability of this RR Lyrae exhibited in the UVW2 filter is at least 1.5 magnitudes, while the ASAS-SN lightcurve 38 shows a V-band amplitude of only 0.4 magnitudes. Carmo et al 2020 for a review of these systems and example lightcurves; the inferred Gaia temperature is also consistent with this being an EA system).…”

Section: Variable Starssupporting

confidence: 62%

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

Modiano,

Wijnands,

Parikh

et al. 2022

Preprint

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Despite the prevalence of transient-searching facilities operating across most wavelengths, the ultraviolet (UV) transient sky remains to be systematically studied. Therefore, we have recently initiated the Transient Ultraviolet Objects (TUVO) project, with which we search for serendipitous UV transients in data obtained using currently available UV instruments with a strong focus on the UV/Optical (UVOT) telescope aboard the Neil Gehrels Swift Observatory (an overview of the project is described in a companion paper). Here we describe the pipeline (named TUVOpipe) we constructed in order to find such transients in the UVOT data, using difference image analysis. The pipeline is run daily on all new public UVOT data (which are available 6-8 hours after the observations are performed), so we discover transients in near real-time. Transients which last >0.5 days are therefore still active when discovered, allowing for follow-up observations to be performed. From October 1, 2020, to the time of submission, using TUVOpipe we have processed 111 330 individual UVOT images and we currently detect an average rate of ∼100 transient candidates per day. Of these daily candidates, on average ∼30% are real transients (separated by human vetting from the remaining 'bogus' transients which were not discarded automatically within the pipeline). Most of the real transients correspond to known variable stars, though we also detect a significant number of known active galactic nuclei and accreting white dwarfs. TUVOpipe can additionally run in archival mode, whereby all the archival UVOT data of a given field is scoured for 'historical' transients; in this mode we also mostly find variable stars. However, some of the transients we find (in particular in the real-time mode) represent previously unreported new transients, or undiscovered outbursts of previously known transients, predominantly outbursts from cataclysmic variables. In this paper we describe the operation of (both modes of) TUVOpipe and some of the initial results we have so far obtained.

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Section: Variable Starssupporting

confidence: 62%

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

Modiano,

Wijnands,

Parikh

et al. 2022

Preprint

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“…It may be also important to investigate the possible effects that the adopted sample selection or methodology may have on the obtained results. Interestingly, a recent search for DEBs in CSS database by Carmo et al (2020) shows no significant inflation among selected targets. We understand the difficulties on deriving stellar physical parameters without spectroscopic data and on developing a model-independent analysis based only on photometry.…”

Section: The Mass-radius Diagrammentioning

confidence: 96%

Detached eclipsing binaries from the Kepler field: radii and photometric masses of components in short-period systems

Cruz,

Aguilar,

Garrido

et al. 2022

Preprint

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The characterisation of detached eclipsing binaries with low mass components has become important when verifying the role of convection in stellar evolutionary models, which requires model-independent measurements of stellar parameters with great precision. However, spectroscopic characterisation depends on single-target radial velocity observations and only a few tens of well-studied low-mass systems have been diagnosed in this way. We characterise eclipsing detached systems from the Kepler field with low mass components by adopting a purely-photometric method. Based on an extensive multi-colour dataset, we derive effective temperatures and photometric masses of individual components using clustering techniques. We also estimate the stellar radii from additional modelling of the available Kepler light curves. Our measurements confirm the presence of an inflation trend in the mass-radius diagram against theoretical stellar models in the low-mass regime.

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“…Papageorgiou et al (2018) reported an updated catalog of 4683 eclipsing Algol-type binaries (EA) from the CSS survey. The physical parameters of the EA systems were explored by Lee (2015), Papageorgiou et al (2019a), andCarmo et al (2020). Using the same sample of 4683 EA in CSS, Papageorgiou et al (2021) reported 126 EAs with possible quadratic or cyclic period variations.…”

Section: The Catalina Samplementioning

confidence: 99%

New low mass ratio contact binaries in the Catalina Sky Survey

Christopoulou,

Lalounta,

Papageorgiou

et al. 2022

Preprint

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We present the identification and photometric analysis of 30 new low mass ratio (LMR) totally eclipsing contact binaries found in Catalina Sky Survey data. The LMR candidates are identified using Fourier coefficients and visual inspection. We perform a detailed scan in the parameter plane of mass-ratio (𝑞) versus inclination (𝑖) using Phoebe-0.31 scripter to derive the best (𝑞, 𝑖) pair for the initial models. The relative physical parameters are determined from the final model of each system. A Monte-Carlo approach was adopted to derive the parameter errors. The resulting parameters confirm the identification. The approximate absolute physical parameters of the systems are estimated based on the light curve solutions and Gaia early Data Release 3 distances. Twelve out of 30 new systems have fill-out factors 𝑓 > 50% and 𝑞 ≤ 0.25 (deep contact LMR systems), and 8 of them, to within errors, are extreme LMR deep systems with 𝑞 ≤ 0.1. We discuss the evolutionary status of the 30 LMR systems in comparison with the most updated catalog of LMR systems from the literature. The scenario of the LMR systems as pre-merger candidates forming fast rotating stars is investigated for all systems, new and old, based both on Hut's stability criteria and critical instability mass ratio (𝑞 inst ) relation. CSS_J075848.2+125656, with 𝑞/𝑞 inst = 1.23 ± 0.23, and CSS_J093010.1-021624, with 𝑞/𝑞 inst = 1.25 ± 0.23, can be considered as merger candidates.

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Recovering variable stars in large surveys: EAup Algol-type class in the Catalina Survey

Cited by 9 publications

References 74 publications

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

TUVOpipe: a pipeline to search for UV transients with Swift-UVOT

Detached eclipsing binaries from the Kepler field: radii and photometric masses of components in short-period systems

New low mass ratio contact binaries in the Catalina Sky Survey

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