Physical Sciences and Mathematics | Open Access Articles

The Mass Of The Black Hole In The Seyfert 1 Galaxy Ngc 4593 From Reverberation Mapping, Kelly D. Denney, Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge, Edward M. Cackett, Matthias Dietrich, Jeffrey K. J. Fogel, Himel Ghosh, Keith D. Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii

Physics and Astronomy Faculty Research Publications

We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the Hβ emission-line light curve with the optical continuum light curve reveals an emission-line time delay of τ_cent=3.73+/-0.75 days. By combining this time delay with the Hβ line width, we derive a central black hole mass of M_BH=(9.8+/-2.1)×10⁶ M_solar, an improvement in precision of a factor of several over past results.

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A Reverberation-Based Mass For The Central Black Hole In Ngc 4151, Misty C. Bentz, Kelly D. Denney, Edward M. Cackett, Matthias Dietrich, Jeffery K. Fogel, Himel Ghosh, Keith Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Bradley M. Peterson, Richard W. Pogge, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii

Physics and Astronomy Faculty Research Publications

We have undertaken a new ground-based monitoring campaign to improve the estimates of the mass of the central black hole in NGC 4151. We measure the lag time of the broad Hβ line response compared to the optical continuum at 5100 Å and find a lag of 6.6^+1.1_-0.8 days. We combine our data with the recent reanalysis of UV emission lines by Metzroth and coworkers to calculate a weighted mean of the black hole mass, M_BH=(4.57^+0.57_-0.47)×10⁷ M_solar. The absolute calibration of the black hole mass is based on normalization of …

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Cooling Of The Quasi-Persistent Neutron Star X-Ray Transients Ks 1731-260 And Mxb 1659-29, Edward M. Cackett, Rudy Wijnands, Manuel Linares, Jon M. Miller, Jeroen Homan, Walter H. G. Lewin

Physics and Astronomy Faculty Research Publications

We present Chandra and XMM-Newton X-ray observations that monitor the neutron star cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 for approximately 4 yr after these sources returned to quiescence from prolonged outbursts. In both sources the outbursts were long enough to significantly heat the neutron star crust out of thermal equilibrium with the core. We analyse the X-ray spectra by fitting absorbed neutron star atmosphere models to the observations. The results of our analysis strengthen the preliminary findings of Wijnands et al. that in both sources the neutron star crust cools down very rapidly …

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Xmm-Newton Discovery Of The X-Ray Transient Xmmu J181227.8-181234 In The Galactic Plane, Edward M. Cackett, Rudy Wijnands, Ron Remillard

Physics and Astronomy Faculty Research Publications

We report the discovery of an X-ray transient, observed in outburst with XMM-Newton on 2003 March 20, and with position (J2000, approximate positional error 2arcsec). No known source is present at this position and the source was not detected during published ROSAT or ASCA observations of that region. However, the source may be associated with 1H1812-182 detected by HEAO 1, although the error bars on the HEAO 1 position are very large and the two sources could also be unrelated. Therefore, we name the source XMMU J181227.8-181234. Initially, the source was not detected using the All-Sky Monitor (ASM) on-board the …

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A Chandra X-Ray Observation Of The Globular Cluster Terzan 1, E. M. Cackett, R. Wijnands, C. O. Heinke, D. Pooley, W. H. G. Lewin, J. E. Grindlay, P. D. Edmonds, P. G. Jonker, J. M. Miller

Physics and Astronomy Faculty Research Publications

We present a ~19-ks Chandra Advanced CCD Imaging Spectrometer (ACIS)-S observation of the globular cluster Terzan 1. 14 sources are detected within 1.4arcmin of the cluster centre with two of these sources predicted to be not associated with the cluster (background active galactic nuclei or foreground objects). The neutron star X-ray transient, X1732-304, has previously been observed in outburst within this globular cluster with the outburst seen to last for at least 12yr. Here, we find four sources that are consistent with the ROSAT position for this transient, but none of the sources are fully consistent with the position of …

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Photoionized HΒ Emission In Ngc 5548: It Breathes!, Edward M. Cackett, Keith Horne

Physics and Astronomy Faculty Research Publications

Emission-line regions in active galactic nuclei (AGNs) and other photoionized nebulae should become larger in size when the ionizing luminosity increases. This `breathing' effect is observed for the Hβ emission in NGC 5548 by using Hβ and optical continuum light curves from the 13-yr (1989-2001) AGN Watch monitoring campaign. To model the breathing, we use two methods to fit the observed light curves in detail: (i) parametrized models and, (ii) the MEMECHO reverberation-mapping code. Our models assume that optical continuum variations track the ionizing radiation, and that the Hβ variations respond with time-delays τ due to light travel-time. By fitting …

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X-Ray Variability During The Quiescent State Of The Neutron Star X-Ray Transient In The Globular Cluster Ngc 6440, Edward M. Cackett, Rudy Wijnands, Craig O. Heinke, Peter D. Edmonds, Walter H. G. Lewin, David Pooley, Jonathan E. Grindlay, Peter G. Jonker, Jon M. Miller

Physics and Astronomy Faculty Research Publications

The globular cluster NGC 6440 is known to harbor a bright neutron star X-ray transient. We observed the globular cluster with Chandra on two occasions when the bright transient was in its quiescent state, in 2000 July and 2003 June (both observations were made nearly 2 yr after the end of their preceding outbursts). The quiescent spectrum during the first observation is well represented by a two-component model (a neutron star atmosphere model plus a power-law component that dominates at energies above 2 keV). During the second observation (which was roughly of equal duration to the first observation) we found …

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Physics and Astronomy Faculty Research Publications

Physics and Astronomy Faculty Research Publications

Cooling Of The Quasi-Persistent Neutron Star X-Ray Transients Ks 1731-260 And Mxb 1659-29, Edward M. Cackett, Rudy Wijnands, Manuel Linares, Jon M. Miller, Jeroen Homan, Walter H. G. Lewin

Physics and Astronomy Faculty Research Publications

Xmm-Newton Discovery Of The X-Ray Transient Xmmu J181227.8-181234 In The Galactic Plane, Edward M. Cackett, Rudy Wijnands, Ron Remillard

Physics and Astronomy Faculty Research Publications

A Chandra X-Ray Observation Of The Globular Cluster Terzan 1, E. M. Cackett, R. Wijnands, C. O. Heinke, D. Pooley, W. H. G. Lewin, J. E. Grindlay, P. D. Edmonds, P. G. Jonker, J. M. Miller

Physics and Astronomy Faculty Research Publications

Photoionized HΒ Emission In Ngc 5548: It Breathes!, Edward M. Cackett, Keith Horne

Physics and Astronomy Faculty Research Publications

X-Ray Variability During The Quiescent State Of The Neutron Star X-Ray Transient In The Globular Cluster Ngc 6440, Edward M. Cackett, Rudy Wijnands, Craig O. Heinke, Peter D. Edmonds, Walter H. G. Lewin, David Pooley, Jonathan E. Grindlay, Peter G. Jonker, Jon M. Miller

Physics and Astronomy Faculty Research Publications