Alternation of the flickering morphology between the high and low state in MV Lyrae

Dobrotka, A.; Negoro, H.; Konopka, Piotr Jan

doi:10.1051/0004-6361/201935569

Cited by 7 publications

(12 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We studied the fast stochastic variability (flickering) and found a characteristic frequency near log(f /Hz) ≃ -3 in the corresponding PDSs. We thus increase the number of detections of this characteristic frequency, and obtained further evidence that all CVs in the optical high state show this flickering frequency, as recently proposed by Dobrotka et al (2020). The confidence of this statement was 69% before the new data analysis contained in this paper.…”

Section: Discussionsupporting

confidence: 81%

“…In this work, we increased the number of detections to 13. The histogram feature at log(f /Hz) ≃ -3 now shows 5 values compared to 4 in the histogram of Dobrotka et al (2020).…”

Section: The Significance Of the New Measurementmentioning

confidence: 87%

“…Therefore, V4743 Sgr is similar to nova-like systems, and the source of the flickering has a different origin compared to standard intermediate polars (Revnivtsev et al 2010). This would be one of those rare cases in which the flickering originates in the central portion of the disk with a hot X-ray corona (Scaringi 2014) like in MV Lyr (Scaringi 2014, Dobrotka et al 2020).…”

Section: Discussionmentioning

confidence: 98%

“…Other systems like VW Hyi, WW Cet and T Leo were observed in X-rays, revealing a single characteristic frequency (Balman & Revnivtsev 2012) or multiple components in SS Cyg (Balman & Revnivtsev 2012) or RU Peg (Dobrotka et al 2014). Dobrotka et al (2020) summarized all these detections, suggesting that two characteristic frequencies can exist in the low state, with an additional and most prominent frequency with log(f /Hz) ≃ -3 in the high state. However, this suggestion was based on only 12 detections.…”

Section: Introductionmentioning

confidence: 93%

“…We searched for characteristic frequencies in the PDSs and found a value of log(f /Hz) ≃ -3.01. Dobrotka et al (2020) summarized all the detected characteristic frequencies in CVs in optical and X-rays. They collected 12 values, and the resulting histogram (Fig.…”

Section: The Significance Of the New Measurementmentioning

confidence: 99%

See 4 more Smart Citations

Searching for the 1 mHz variability in the flickering of V4743 Sgr: a Cataclysmic Variable accreting at a high rate

Dobrotka,

Orio,

Benka

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Aims. A few well studied cataclysmic variables (CVs) have shown discrete characteristic frequencies of fast variability; the most prominent ones are around log(f /Hz) ≃ -3. Because we still have only small number statistics, we obtained a new observation to test whether this is a general characteristic of CVs, especially if mass transfer occurs at a high rate typical for dwarf nova in outbursts, in the so called "high state". Methods. We analyzed optical Kepler data of the quiescent nova and intermediate polar V4743 Sgr. This system hosts a white dwarf accreting through a disk in the high state. We calculated the power density spectra, and searched for break or characteristic frequencies. Our goal is to assess whether the mHz frequency of the flickering is a general characteristic. Results. V4743 Sgr has a clear break frequency at log(f /Hz) ≃ -3. This detection increases the probability that the mHz characteristic frequency is a general feature of CVs in the high state, from 69% to 91%. Furthermore, we propose the possibility that the variability is generated by similar mechanism as in the nova-like system MV Lyr, which would make V4743 Sgr unique.

show abstract

Section: Discussionsupporting

confidence: 81%

“…In this work, we increased the number of detections to 13. The histogram feature at log(f /Hz) ≃ -3 now shows 5 values compared to 4 in the histogram of Dobrotka et al (2020).…”

Section: The Significance Of the New Measurementmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 93%

Section: The Significance Of the New Measurementmentioning

confidence: 99%

See 3 more Smart Citations

Searching for the 1 mHz variability in the flickering of V4743 Sgr: a Cataclysmic Variable accreting at a high rate

Dobrotka,

Orio,

Benka

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Searching for the 1 mHz variability in the flickering of V4743 Sgr: A cataclysmic variable accreting at a high rate

Dobrotka

Orio

Benka

et al. 2021

A&A

Self Cite

View full text Add to dashboard Cite

Aims. A few well studied cataclysmic variables (CVs) have shown discrete characteristic frequencies of fast variability; the most prominent ones are around log(f/Hz) ≃ −3. Because we still have only small number statistics, we obtained a new observation to test whether this is a general characteristic of CVs, especially if mass transfer occurs at a high rate typical for dwarf nova in outbursts, in the so called high state. Methods. We analysed optical Kepler data of the quiescent nova and intermediate polar V4743 Sgr. This system hosts a white dwarf accreting through a disc in the high state. We calculated the power density spectra and searched for break or characteristic frequencies. Our goal is to assess whether the milihertz frequency of the flickering is a general characteristic. Results. V4743 Sgr has a clear break frequency at log(f/Hz) ≃ −3. This detection increases the probability that the megahertz characteristic frequency is a general feature of CVs in the high state, from 69% to 91%. Furthermore, we propose the possibility that the variability is generated by a similar mechanism as in the nova-like system MV Lyr, which would make V4743 Sgr unique.

show abstract

XMM-Newton observation of V1504 Cyg as a probe for the existence of an evaporated corona

Dobrotka¹,

Ness²,

Nucita³

et al. 2023

A&A

View full text Add to dashboard Cite

Aims. We present an analysis of an XMM-Newton observation of the dwarf nova V1504 Cyg during the decline from an outburst. Our goal is to search for evidence of an evaporated X-ray corona. Such a corona can be understood as an optically thin and geometrically thick disc around the central part of an optically thick and geometrically thin disc. Methods. We study the X-ray spectra of a dwarf nova using a cooling-flow model and the evolution in the amplitude of variability and power density spectra in the UV and X-ray. Results. The X-ray (pn) count rate increases from initially around 0.03 cps to 0.17 cps, with a harder spectrum and a higher degree of variability. Meanwhile, the OM/UVW1 light curve follows a slow decline with a decreasing amplitude of variability. Next, we split the X-ray data into two segments and analysed them separately. Both were described by a cooling-flow model, while the first low-luminosity segment required an additional power-law component, suggesting the presence of a wind. A spectral fitting revealed a higher temperature for the second brighter segment. A timing analysis revealed a potential break frequency at log(f/Hz) = −3.02 during the decline towards the quiescence. This detection is in agreement with optical data from Kepler observations. Conclusions. The X-ray nature of the break frequency supports the innermost parts of the disc as source of the variability. Moreover, a similar frequency was observed in several other cataclysmic variables. Thus, a sandwich model where a geometrically thick corona surrounds the geometrically thin disc is a plausible accretion configuration.

show abstract

Alternation of the flickering morphology between the high and low state in MV Lyrae

Cited by 7 publications

References 40 publications

Searching for the 1 mHz variability in the flickering of V4743 Sgr: a Cataclysmic Variable accreting at a high rate

Searching for the 1 mHz variability in the flickering of V4743 Sgr: a Cataclysmic Variable accreting at a high rate

Searching for the 1 mHz variability in the flickering of V4743 Sgr: A cataclysmic variable accreting at a high rate

XMM-Newton observation of V1504 Cyg as a probe for the existence of an evaporated corona

Contact Info

Product

Resources

About