scholarly journals A Search for Cataclysmic Binaries in the Globular Cluster M3

1985 ◽  
Vol 113 ◽  
pp. 103-104
Author(s):  
M. M. Shara ◽  
A. F. J. Moffat ◽  
D. A. Hanes
Keyword(s):  
Emission Line ◽  
Globular Cluster ◽  
Equivalent Width ◽  
Dwarf Novae ◽  
X Ray ◽  
Cataclysmic Binaries ◽  
Line Equivalent Width

Deep Hβ narrowband and broadband images of M3 have been electronically blinked to search for cataclysmic binaries. Tests of the method on a known, faint cataclysmic enable us to set limits on the sensitivity of the technique. No bright (MB < 6) emission-line (equivalent width > 12 Å) cataclysmic binaries exist in M3 between 4 and 30 core radii from the center. Low luminosity globular X-ray sources could still be weak-lined (E.W. < 12 Å) and bright (MB ≃ +5 like some old novae) or strong-lined (E.W. ≃ 60 Å) and faint (MB > 7 like dwarf novae).

scholarly journals The X-Ray Nova GRO J0422+32 in Decline and Quiescence

1996 ◽  
Vol 158 ◽  
pp. 399-400
Author(s):  
M. R. Garcia ◽  
P. J. Callanan ◽  
J. E. McClintock ◽  
P. Zhao
Keyword(s):  
Emission Line ◽  
Emission Region ◽  
Dwarf Novae ◽  
X Ray ◽  
First Order ◽  
Band Emission ◽  
Line Region ◽  
Hα Emission ◽  
The Stability ◽  
The Continuum

We have followed the X-ray nova GRO J0422+32, spectroscopically and photometrically, throughout the decline to quiescence.In the final stages of decay (days 430…880 after the outburst, see Callanan et al. (1995) for the epoch 1995), the equivalent width (EW) of the Hα emission increases monotonically and the R magnitude decreases monotonically. This suggests that the flux in the Hα line is constant, while the continuum fades. The Hα flux is the product of the R band flux (F(R), arbitrarily scaled to 100 at R = 19 mag) and the EW, and is shown in the last column of the table below. The Hα flux varies by only ~ 30% while the continuum fades by a factor of eight (from R = 19 mag to R = 21.3 mag). So, to first order, the Hα luminosity is constant in the final stages of decay. While it is generally the case that the emission line EWs in individual dwarf novae also increase during the decay, the exact behavior seen in GRO J0422+32 is not what is seen for dwarf novae (on average). Using the relation between EW[Hβ] and Mv given in figure 6 of Patterson (1984), we would expect a factor of ~ 5 variation in the Hα flux during days 430…880. The stability of the Hα flux implies that somehow the emission line region is ‘disconnected’ from the continuum (R–band) emission region.

scholarly journals A Candidate for the Recovered Nova of 1938 in the Globular Cluster M 14

1988 ◽  
Vol 126 ◽  
pp. 585-586
Author(s):  
Michael M. Shara ◽  
Michael Potter ◽  
Anthony F. J. Moffat ◽  
Helen Sawyer Hogg ◽  
Amelia Wehlau
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Close Binaries ◽  
Dwarf Novae ◽  
X Ray ◽  
Negative Results ◽  
Classical Nova ◽  
M 14

Although close binaries are believed to be of importance in the dynamical evolution of globular clusters, searches for such binaries have produced mostly negative results, aside from x-ray sources. Two dwarf novae which are possible cluster members are known (Margon and Downes 1983) and two classical nova candidates have been found. The crowded field around the nova observed in 1860 close to the center of M80 makes ground-based recovery of that star impossible with present techniques. Here we report on our attempt to recover the star which erupted in 1938 about 30″ (0.8 core radii) from the center of M14.

Cataclysmic binaries in star clusters. 1: A search for erupting dwarf novae in the globular cluster M92

1994 ◽  
Vol 429 ◽  
pp. 767 ◽  
Author(s):  
Michael M. Shara ◽  
Louis E. Bergeron ◽  
Anthony F. J. Moffat
Keyword(s):  
Globular Cluster ◽  
Star Clusters ◽  
Dwarf Novae ◽  
Cataclysmic Binaries

scholarly journals Spectral observations of X Persei: Connection between Hα and X-ray emission

2019 ◽  
Vol 622 ◽  
pp. A173 ◽  
Author(s):  
R. Zamanov ◽  
K. A. Stoyanov ◽  
U. Wolter ◽  
D. Marchev ◽  
N. I. Petrov
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Equivalent Width ◽  
Roche Lobe ◽  
Published Data ◽  
Expansion Velocity ◽  
X Ray ◽  
Spectroscopic Observations ◽  
Show Evidence ◽  
Disc Size

We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999–2018. Using new and published data, we found that during “disc-rise” the expansion velocity of the circumstellar disc is 0.4–0.7 km s−1. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the disc by resonances 10:1, 3:1, and 2:1, while the maximum disc size is larger than the Roche lobe of the primary and smaller than the closest approach of the neutron star. We find correlation between equivalent width of Hα emission line (Wα) and the X-ray flux, which is visible when 15 Å < Wα ≤ 40 Å. The correlation is probably due to wind Roche lobe overflow.

scholarly journals The profile and equivalent width of the X-ray iron emission line from a disc around a Kerr black hole

1997 ◽  
Vol 288 (1) ◽  
pp. L11-L15 ◽  
Author(s):  
Y. Dabrowski ◽  
A. C. Fabian ◽  
K. Iwasawa ◽  
A. N. Lasenby ◽  
C. S. Reynolds
Keyword(s):  
Black Hole ◽  
Emission Line ◽  
Equivalent Width ◽  
Kerr Black Hole ◽  
X Ray

scholarly journals Dependence of equivalent width of quasar emission lines on UV-optical spectral index

2013 ◽  
Vol 9 (S304) ◽  
pp. 282-283 ◽  
Author(s):  
Olena Torbaniuk ◽  
Ganna Ivashchenko
Keyword(s):  
Emission Line ◽  
Spectral Index ◽  
Equivalent Width ◽  
Emission Lines ◽  
Baldwin Effect ◽  
Quasar Spectra ◽  
Composite Spectra ◽  
Spectral Ranges ◽  
The Baldwin Effect ◽  
Line Equivalent Width

AbstractUsing 192 composite spectra stacked from subsamples of individual SDSS quasar spectra binned in spectral index, αλ, and logarithm of monochromatic luminosity at 1450 Å, log l1450, and modelling separate spectral ranges with superposition of emission lines it was found that: there is a dependence of emission line equivalent width (EW) on αλ (correlation or anti-correlation) for some lines, mostly for those lines for which the Baldwin effect is detected, while for the lines for which the Baldwin effect is not observed any αλ-dependence was found.

GINGA OBSERVATIONS OF X0512–401 IN THE GLOBULAR CLUSTER NGC1851

1993 ◽  
Vol 02 (04) ◽  
pp. 497-507
Author(s):  
E.N. ERCAN ◽  
A.M. CRUISE ◽  
B.J. KELLETT
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Accretion Disk ◽  
Power Law ◽  
Globular Cluster ◽  
Third Body ◽  
X Ray ◽  
Two Component ◽  
Low Mass ◽  
Best Fit

We present here the first detailed spectral observations of the low-mass X-ray binary source X0512–401 located in the globular cluster NGC1851 obtained by Ginga. We have found that the Ginga LAC data of X0512–401 are best fitted by a “two-component” spectral model: power-law with exponential cut-off and a blackbody. The inclusion of a 6.7 KeV Fe emission line did not improve our best fit. In the light of the present observations and the previous studies concerning the importance of Comptonization, our model requires a scattering cloud surrounding the neutron star, with a Thomson optical depth of ~5. The detection of ~30–40 hr periodicity is hard to interpret in terms of the possible binary period of the system, since most of these systems have binary periods of a few hours or even less. It may either suggest that the accretion disk around the neutron star is precessing or there is a third body in the system.

The X-Ray Spectrum of the X-Ray Binary 4U 1728-34, observed with Suzaku

2017 ◽  
Vol 14 (S339) ◽  
pp. 323-326
Author(s):  
Y. Lei ◽  
H. Zhang ◽  
H. Yuan ◽  
Y. Zhang
Keyword(s):  
Emission Line ◽  
Equivalent Width ◽  
Gaussian Component ◽  
Power Law Model ◽  
Disk Model ◽  
X Ray ◽  
Broad Emission ◽  
Energy Plus ◽  
Broad Emission Line ◽  
The Continuum

AbstractThis poster reported our spectroscopy of the neutron-star X-ray binary 4U 1728-34, observed with Suzaku in 2010 October. It is classified as an atoll source. Its continuous X-ray spectrum can be fitted by a combination of a multicolour accretion-disk model for the soft energy, plus a power-law model for the hard energy. A broad emission line at 6–7 keV can be fitted well using a simple Gaussian component with an equivalent width of ∼322 eV. However, for this object the presence of that feature is disputed, even though our results from Suzaku do suggest the presence of a broad Fe emission line that is consistent with results from XMM-Newton. Nevertheless, the parameters of the line (the line centroid and the equivalent width) are a little different, but that could be due to a difference in modelling the continuum.

scholarly journals An X-ray Emitting Black Hole in a Globular Cluster

2007 ◽  
Vol 3 (S246) ◽  
pp. 336-340
Author(s):  
T.J. Maccarone ◽  
G. Bergond ◽  
A. Kundu ◽  
K.L. Rhode ◽  
J.J. Salzer ◽  
...  
Keyword(s):  
Black Hole ◽  
Light Curve ◽  
Emission Line ◽  
Globular Cluster ◽  
Strong Evidence ◽  
Optical Spectrum ◽  
Optical Counterpart ◽  
Variable Source ◽  
X Ray

AbstractWe present optical and X-ray data for the first object showing strong evidence for being a black hole in a globular cluster. We show the initial X-ray light curve and X-ray spectrum which led to the discovery that this is an extremely bright, highly variable source, and thus must be a black hole. We present the optical spectrum which unambiguously identifies the optical counterpart as a globular cluster, and which shows a strong, broad [O III] emission line, most likely coming from an outflow driven by the accreting source.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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