Broad-line region size and black hole mass in high-z AGN (2008)
Botti, Ismael, Lira, Paulina, Netzer, Hagai, Kaspi, Shai, Maza, Jose, Maoz, Dan
In this contribution we briefly review the reverberation mapping technique and its results for low and intermidiate luminosity AGNs. Then we present a monitoring campaign of high-luminosity...
Shemmer, Ohad, Brandt, W. N., Netzer, Hagai, Maiolino, Roberto, Kaspi, Shai
We study the hard-X-ray spectral properties of ten highly luminous radio-quiet (RQ) active galactic nuclei (AGNs) at z=1.3-3.2, including new XMM-Newton observations of four of these sources. We find...
The Centurion 18 telescope of the Wise Observatory (2008)
Brosch, Noah, Polishook, David, Shporer, Avi, Kaspi, Shai, Berwald, Assaf, Manulis, Ilan
We describe the second telescope of the Wise Observatory, a 0.46-m Centurion 18 (C18) installed in 2005, which enhances significantly the observing possibilities. The telescope operates from a small...
Advances in Reverberation Mapping (2007)
This contribution briefly reviews the reverberation mapping technique which leads to determination of black hole masses. I focus on the emerging relation between the broad-line region size and the...
Holczer, Tomer, Behar, Ehud, Kaspi, Shai
We analyze the Chandra X-ray spectrum obtained with the HETGS grating spectrometer of IRAS 13349+2438, which has one of the richest absorption spectra of a quasar outflow. Absorption from almost all...
Reverberation Mapping of High-Luminosity Quasars: First Results (2006)
Kaspi, Shai, Brandt, W. N., Maoz, Dan, Netzer, Hagai, Schneider, Donald P., Shemmer, Ohad
Reverberation mapping of nearby active galactic nuclei has led to estimates of broad-line-region (BLR) sizes and central-object masses for some 37 objects to date. However, successful reverberation...
Desroches, Louis-Benoit, Filippenko, Alexei V., Kaspi, Shai, Laor, Ari, Maoz, Dan, Ganeshalingam, Mohan, ...
We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out over two nights in 2004...
Shemmer, Ohad, Brandt, W. N., Netzer, Hagai, Maiolino, Roberto, Kaspi, Shai
We present new XMM-Newton observations of two luminous and high accretion-rate radio-quiet active galactic nuclei (AGNs) at z~2. Together with archival X-ray and rest-frame optical spectra of three...
O'Neill, Paul M., Kaspi, Shai, Laor, Ari, Nandra, Kirpal, Moran, Edward C., Peterson, Bradley M., ...
We report on two Chandra observations, and a simultaneous Hubble Space Telescope ultraviolet observation, of the dwarf Seyfert 1 galaxy NGC 4395. Each Chandra observation had a duration of ~30 ks,...
The High-Velocity Outflow of PG 1211+143: An Unbiased View Based on Several Observations (2005)
We present and discuss high-resolution grating spectra of the quasar PG1211+143 obtained over three years. Based on an early observation from 2001, we find an outflow component of about 3000 km/s in...
The High-Velocity Outflow of PG1211+143 May Not be That Fast (2005)
We analyze the X-ray spectrum of the quasar PG1211+143 observed with the CCD and grating spectrometers on board XMM-Newton. Using an ion by ion fitting model we find an outflow component of about...
Is The Fe M-shell Absorber Part of The Outflow in Active Galactic Nuclei? (2005)
Holczer, Tomer, Behar, Ehud, Kaspi, Shai
The X-ray emission of many active galactic nuclei (AGNs) is absorbed between 15 and 17 Angstrom by means of unresolved (inner-shell) transition arrays (UTAs) of Fe M-shell ions. The outflow...
Peterson, Bradley M., Bentz, Misty C., Desroches, Louis-Benoit, Filippenko, Alexei V., Ho, Luis C., Kaspi, Shai, ...
A reverberation-mapping program on NGC 4395, the least-luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, yields a measurement of...
XMM-Newton Spectroscopy of the Starburst Dominated Ultra Luminous Infrared Galaxy NGC 6240 (2005)
Netzer, Hagai, Lemze, Doron, Kaspi, Shai, George, I. M., Turner, T. J., Lutz, D., ...
We present new XMM-Newton observation of the Ultra Luminous Infrared Galaxy (ULIRG) NGC 6240. We analyze the reflecting grating spectrometer (RGS) data, and data from the other instruments, and find...
The Relationship Between Luminosity and Broad-Line Region Size in Active Galactic Nuclei (2005)
Kaspi, Shai, Maoz, Dan, Netzer, Hagai, Peterson, Bradley M., Vestergaard, Marianne, Jannuzi, Buell T.
We reinvestigate the relationship between the characteristic broad-line region size (R_blr) and the Balmer emission-line, X-ray, UV, and optical continuum luminosities. Our study makes use of the...
XMM-Newton spectroscopy of the starburst-dominated ultraluminous infrared galaxy NGC 6240 (2005)
Netzer, Hagai, Lemze, Doron, Kaspi, Shai, George, I. M., Turner, T. J., Lutz, D., ...
Peterson, Bradley, Ferrarese, Laura, Gilbert, Karoline, Kaspi, Shai, Malkan, Matthew, Maoz, Dan, ...
Also archived in: arXiv:astro-ph/0407299 v1 14 Jul 2004
High resolution X-ray spectra of quasars (2004)
Past X-ray observations by ASCA suggest that warm absorbers (O VII and O VIII edges) are apparently rare in high luminosity AGNs (quasars) while they are more common in low luminosity AGNs...
The Properties and the Evolution of the Highly Ionized Gas in MR2251-178 (2004)
Kaspi, Shai, Netzer, Hagai, Chelouche, Doron, George, Ian M., Nandra, Kirpal, Turner, T. J.
(abridged) We present the first XMM-Newton observations of the radio-quiet quasar MR2251-178 obtained in 2000 and 2002. The EPIC-pn spectra show a power-law continuum with a slope of 1.6 at high...
Kaspi, Shai, Brandt, W. N., Collinge, M. J., Elvis, Martin, Reynolds, Christopher S.
We present three Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the Narrow-Line Seyfert 1 galaxy NGC4051. The most prominent features in the far-ultraviolet (FUV) spectrum are the OVI...
Reverberation Mapping of High-Redshift, High-Luminosity Quasars (2002)
Kaspi, Shai, Netzer, Hagai, Maoz, Dan, Shemmer, Ohad, Brandt, W. N., Schneider, Donald P.
We present preliminary results from a reverberation mapping program to measure the Broad Line Region size in high-redshift, high-luminosity quasars. The observations are carried out at the...
The Ionized Gas and Nuclear Environment in NGC 3783 II. Averaged HST/STIS and FUSE Spectra (2002)
Gabel, Jack R., Crenshaw, D. Michael, Kraemer, Steven B., Brandt, W. N., George, Ian M., Hamann, Frederick W., ...
We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the STIS/HST and FUSE. We have coadded multiple STIS and FUSE observations to obtain a high S/N...
Collinge, M. J., Brandt, W. N., Kaspi, Shai, Crenshaw, D. Michael, Elvis, Martin, Kraemer, Steven B., ...
We present the results from simultaneous observations of the Narrow-Line Seyfert 1 galaxy NGC 4051 with the Chandra High Energy Transmission Grating Spectrometer and the HST Space Telescope Imaging...
Kaspi, Shai, Brandt, W. N., Netzer, Hagai, George, Ian M., Chartas, George, Behar, Ehud, ...
(abridged) The high-resolution X-ray spectrum of NGC 3783 shows several dozen absorption lines and a few emission lines from the H-like and He-like ions of O, Ne, Mg, Si, and S as well as from Fe...
A 7.5 years spectrophotometric monitoring program of 28 Palomar-Green quasars to determine the size of their broad emission line region (BLR) is reviewed. We find both the continuum and the emission...
Discovery of Narrow X-ray Absorption Lines from NGC 3783 with the Chandra HETGS (2000)
Kaspi, Shai, Brandt, W. N., Netzer, Hagai, Sambruna, Rita, Chartas, George, Garmire, Gordon P., ...
We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory. These spectra...
The X-ray Properties of z>4 Quasars (2000)
Kaspi, Shai, Brandt, W. N., Schneider, Donald P.
We report on a search for X-ray emission from quasars with redshifts greater than four using the ROSAT public database. Our search has doubled the number of z>4 quasars detected in X-rays from 6 to...
Kaspi, Shai, Smith, Paul S., Netzer, Hagai, Maoz, Dan, Jannuzi, Buell T., Giveon, Uriel
(abridged) We have spectrophotometrically monitored a well-defined sample of 28 Palomar-Green quasars in order to obtain measurements of their BLRs and to investigate the relationships between quasar...
Modeling Variable Emission Lines in AGNs: Method and Application to NGC 5548 (1999)
We present a new scheme for modeling the broad line region in active galactic nuclei (AGNs). It involves photoionization calculations of a large number of clouds, in several pre-determined...
Long-term optical variability properties of the Palomar-Green quasars (1999)
Giveon, Uriel, Maoz, Dan, Kaspi, Shai, Netzer, Hagai, Smith, Paul S.
We present results from a monitoring program of 42 quasars from the Palomar Green sample. The objects were observed for 7 years at the Wise Observatory, as part of a long term effort to monitor AGN...
The Discovery of a Nearby M Dwarf (1998)
We report the discovery of a nearby M dwarf star, found accidentally while observing the old nova DN Gem at the Wise Observatory. The star is designated 1200-05296925 in the PMM USNO-A1.0 catalogue...
BLR Modeling: A New Approach (1998)
We present a new scheme for modeling the broad line region in active galactic nuclei. It involves photoionization calculations applied to a number of variable emission lines at {\it all times}. We...
Peterson, Bradley M., Wanders, Ignaz, Horne, Keith, Collier, Stefan, Alexander, Tal, Kaspi, Shai, ...
We describe a model-independent method of assessing the uncertainties in cross-correlation lags determined from AGN light curves, and use this method to investigate the reality of lags between UV and...
Measurement of the Broad Line Region Size in Two Bright Quasars (1996)
Kaspi, Shai, Smith, Paul S., Maoz, Dan, Netzer, Hagai, Jannuzi, Buell. T.
We present 4 years of spectrophotometric monitoring data for two radio-quiet quasars, PG 0804+762 and PG 0953+414, with typical sampling intervals of several months. Both sources show continuum and...