XMM-NEWTON OBSERVATIONS OF THE DWARF NOVA RU Peg IN QUIESCENCE: PROBE OF THE BOUNDARY LAYER

Download
2011-11-10
Balman, Şölen
Godon, Patrick
Sion, Edward M.
Ness, Jan-Uwe
Schlegel, Eric
Barrett, Paul E.
Szkody, Paula
We present an analysis of X-ray and UV data obtained with the XMM-Newton Observatory of the long-period dwarf nova RU Peg. RU Peg contains a massive white dwarf (WD), possibly the hottest WD in a dwarf nova (DN), it has a low inclination, thus optimally exposing its X-ray emitting boundary layer (BL), and has an excellent trigonometric parallax distance. We modeled the X-ray data using XSPEC assuming a multi-temperature plasma emission model built from the MEKAL code (i.e., CEVMKL). We obtained a maximum temperature of 31.7 keV, based on the European Photon Imaging Camera MOS1, 2 and pn data, indicating that RU Peg has an X-ray spectrum harder than most DNe, except U Gem. This result is consistent with and indirectly confirms the large mass of the WD in RU Peg. The X-ray luminosity we computed corresponds to a BL luminosity for a mass accretion rate of 2 x 10(-11) M-circle dot yr(-1) (assuming M-wd = 1.3 M-circle dot), in agreement with the expected quiescent accretion rate. The modeling of the O VIII emission line at 19 angstrom as observed by the Reflection Grating Spectrometer implies a projected stellar rotational velocity v(rot) sin i = 695 km s(-1), i.e., the line is emitted from material rotating at similar to 936-1245 km s(-1) (i similar to 34 degrees-48 degrees) or about 1/6 of the Keplerian speed; this velocity is much larger than the rotation speed of the WD inferred from the Far Ultraviolet Spectroscopic Explorer spectrum. Cross-correletion analysis yielded an undelayed (time lag similar to 0) component and a delayed component of 116 +/- 17 s where the X-ray variations/fluctuations lagged the UV variations. This indicates that the UV fluctuations in the inner disk are propagated into the X-ray emitting region in about 116 s. The undelayed component may be related to irradiation effects.
ASTROPHYSICAL JOURNAL

Suggestions

XMM-NEWTON OBSERVATIONS OF LUMINOUS SOURCES IN NEARBY GALAXIES NGC 4395, NGC 4736, AND NGC 4258
AKYÜZ, AYSUN; Kayaci, S.; Avdan, H.; Ozel, M. E.; SONBAŞ, EDA; Balman, Şölen (IOP Publishing, 2013-03-01)
We present the results of a study of non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources have been detected within the D-25 regions of the target galaxies. The large collecting area of XMM-Newton makes the statistics sufficient to obtain spectral fitting for 16 (about 20%) of these sources. Compiling the extensive archival expo...
X-RAY SPECTRAL AND OPTICAL PROPERTIES OF A ULX IN NGC 4258 (M106)
Avdan, H.; Avdan, S.; AKYÜZ, AYSUN; Balman, Şölen; AKSAKER, NAZIM; AKKAYA ORALHAN, Inci (American Astronomical Society, 2016-09-10)
We study the X-ray and optical properties of the ultraluminous X-ray source (ULX) X-6 in the nearby galaxy NGC 4258 (M106) based on the archival XMM-Newton, Chandra, Swift, and Hubble Space Telescope (HST) observations. The source has a peak luminosity of L-X similar to 2 x 10(39) erg s(-1) in the XMM-Newton observation of 2004 June. Consideration of the hardness ratios and the spectral model parameters shows that the source seems to exhibit possible spectral variations throughout the X-ray observations. In...
Chandra observation of the shell of Nova Persei 1901 (GK Persei): Detection of localized nonthermal X-ray emission from a miniature supernova remnant
Balman, Şölen (IOP Publishing, 2005-07-10)
I present data on the shell of classical Nova Persei (1901) obtained by the Advanced CCD Imaging Spectrometer S3 detector on board the Chandra X-Ray Observatory. The X-ray nebula is affected mostly by the complex interstellar medium around the nova and has not developed a regular shell. The X-ray nebula is lumpy and asymmetric, with the bulk of the emission coming from the southwestern quadrant. The brightest X-ray emission is detected as an arc that covers the region from the west to the south of the centr...
X-ray spectral evolution of Her X-1 in a low state and the following short high state
Inam, SC; Baykal, Altan (Oxford University Press (OUP), 2005-08-21)
We analysed spectral variations of similar to 8.5-d long Rossi X-ray Timing Explorer (RXTE) monitoring observations of Her X-1 in 2001 December. This set of observations enables, for the first time, frequent continuous monitoring (111 pointings in similar to 8.5 d) of the source with RXTE including a similar to 1.7-d-long low state part and the following similar to 6.8-d-long short high state part. We used an absorbed power-law model with an iron line energy complex modelled as a Gaussian to fit both the 3-...
LOCALIZING INTEGRAL SOURCES WITH CHANDRA: X-RAY AND MULTI-WAVELENGTH IDENTIFICATIONS AND ENERGY SPECTRA
Tomsick, John A.; Bodaghee, Arash; Chaty, Sylvain; Rodriguez, Jerome; Rahoui, Farid; Halpern, Jules; KALEMCİ, EMRAH; Arabaci, Mehtap Ozbey (American Astronomical Society, 2012-08-01)
We report on Chandra observations of 18 hard X-ray (>20 keV) sources discovered with the INTEGRAL satellite near the Galactic plane. For 14 of the INTEGRAL sources, we have uncovered one or two potential Chandra counterparts per source. These provide soft X-ray (0.3-10 keV) spectra and subarcsecond localizations, which we use to identify counterparts at other wavelengths, providing information about the nature of each source. Despite the fact that all of the sources are within 5 degrees of the plane, four o...
Citation Formats
Ş. Balman et al., “XMM-NEWTON OBSERVATIONS OF THE DWARF NOVA RU Peg IN QUIESCENCE: PROBE OF THE BOUNDARY LAYER,” ASTROPHYSICAL JOURNAL, pp. 0–0, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51937.