Orbital periods of cataclysmic variables identified by the SDSS

Dillon, Monihar; Gänsicke, B. T.; Aungwerojwit, A.; Rodríguez‐Gil, P.; Marsh, T. R.; Barros, S. C. C.; Szkody, Paula; Brady, Steve; Krajci, Thomas; Oksanen, A.

doi:10.1111/j.1365-2966.2008.13170.x

Cited by 49 publications

(33 citation statements)

References 63 publications

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“…1 http://www.sdss.org/ much less affected by these selection biases. Further information and previous results can be found in Gänsicke et al (2006), Southworth et al (2006Southworth et al ( , 2007aSouthworth et al ( ,b, 2008a and Dillon et al (2008). A major recent result of our project is the identification of the long-predicted pile-up of objects at the minimum period (the "period spike"), which is discussed in detail by Gänsicke et al (2009).…”

Section: Introductionmentioning

confidence: 98%

Southworth

Copperwheat

Gänsicke

et al. 2010

A&A

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We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital periods. The light curves of three of the eclipsing systems are also analysed using the lcurve code, and their mass ratios and orbital inclinations determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 ± 0.0008 min, making it a useful object with which to investigate the evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a period of 131.2432 ± 0.0014 min and is probably magnetic. The white dwarf ingress and egress phases are very deep and short, and there is no clear evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 ± 0.4 and 93.6 ± 0.5 min and mass ratios of 0.14 ± 0.03 and 0.17 ± 0.03, respectively. Their eclipses have well-defined white dwarf and bright spot ingress and egress features, making them excellent candidates for detailed study. All four of the orbital periods presented here are shorter than the 2-3 h period gap observed in the known population of cataclysmic variables.

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Section: Introductionmentioning

confidence: 98%

Orbital periods of cataclysmic variables identified by the SDSS

Southworth

Copperwheat

Gänsicke

et al. 2010

A&A

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“…The magnitudes in the Sloan photometric system were computed using the Johnson-Morgan-Cousins transformation equations in Fukugita et al (1996). In this diagram are plotted, as contours, the spectroscopically identified population of quasars (Richards et al 2001) and cataclysmic variables (Dillon et al 2008, and references therein) from the SDSS, as well as late-type stars (Bilir et al 2005). Only the five INS candidates observed with SOAR are shown, since we do not have U magnitudes for the two candidates observed with the ESO-VLT (sources XMM J1210 and XMM J0106).…”

Section: Identification With Other Classes Of X-ray Emittersmentioning

confidence: 99%

A search for thermally emitting isolated neutron stars in the 2XMMp catalogue

Pires

Motch

Janot-Pacheco³

2009

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The relatively large number of nearby radio-quiet and thermally emitting isolated neutron stars (INSs) discovered in the ROSAT AllSky Survey, dubbed the "Magnificent Seven", suggests that they belong to a formerly neglected major component of the overall INS population. So far, attempts to discover similar INSs beyond the solar vicinity failed to confirm any reliable candidate. The good positional accuracy and soft X-ray sensitivity of the EPIC cameras onboard the XMM-Newton satellite allow us to efficiently search for new thermally emitting INSs. We used the 2XMMp catalogue to select sources with no catalogued candidate counterparts and with X-ray spectra similar to those of the Magnificent Seven, but seen at greater distances and thus undergoing higher interstellar absorptions. Identifications in more than 170 astronomical catalogues and visual screening allowed us to select fewer than 30 good INS candidates. In order to rule out alternative identifications, we obtained deep ESO-VLT and SOAR optical imaging for the X-ray brightest candidates. We report here on the optical follow-up results of our search and discuss the possible nature of 8 of our candidates. A high X-ray-to-optical flux ratio together with a stable flux and soft X-ray spectrum make the brightest source of our sample, 2XMM J104608.7-594306, a newly discovered thermally emitting INS. The X-ray source 2XMM J010642.3+005032 has no evident optical counterpart and should be further investigated. The remaining X-ray sources are most probably identified with cataclysmic variables and active galactic nuclei, as inferred from the colours and flux ratios of their likely optical counterparts. Beyond the finding of new thermally emitting INSs, our study aims at constraining the space density of this Galactic population at great distances and at determining whether their apparently high density is a local anomaly or not.

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“…Our primary aim is to measure the orbital periods of these objects; further information and previous results can be found in Gänsicke et al (2006), Dillon et al (2008) and Southworth et al (2006Southworth et al ( , 2007a. Detecting eclipses is one of the most reliable and straightforward ways of measuring the orbital period of a CV.…”

Section: Introductionmentioning

confidence: 99%