The Einstein database of IPC x-ray observations of optically selected and radio-selected quasars, 1.

Wilkes, B. J.; Tananbaum, H.; Worrall, D. M.; Avni, Y.; Oey, M. S.; Flanagan, J.

doi:10.1086/191959

Cited by 202 publications

(227 citation statements)

References 24 publications

(40 reference statements)

Supporting

Mentioning

196

Contrasting

Unclassified

Order By: Relevance

“…During the RASS it was in the range found for quasars by Yuan et al 1998, Wilkes et al 1994, and Brandt et al 2000, and agrees with the expected value of α ox derived from the optical/UV luminosity as defined by Wilkes et al 1994. The slope α ox derived from the HRI and ASCA observations are much steeper compared to those samples, indicating that RX J2217.9−5941 is deficient in X-rays.…”

Section: Persistent Variability?supporting

confidence: 88%

See 1 more Smart Citation

RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

Grupe

Thomas

Leighly

2001

A&A

View full text Add to dashboard Cite

Abstract. We report the discovery of a highly X-ray variable AGN, RX J2217.9-5941. This object was bright during the ROSAT All-Sky Survey (RASS), during which a decrease in the count rate by a factor of 12 was observed. It was found to be much fainter in follow-up HRI observations and is therefore an X-ray transient AGN candidate. On long time scales of years, its count rate decreased by a factor of about 30 between the RASS and the ROSAT HRI and ASCA observations in 1998. Analysis of the ASCA data, complicated by source confusion and poor statistics, tentatively indicates a steep spectrum in the faint state. There is no evidence for variability among 5 optical observations of the object obtained between 1992 and 1998. We discuss the variability of RX J2217.9-5941 and its possible X-ray transient nature.

show abstract

Section: Persistent Variability?supporting

confidence: 88%

“…12 in Wilkes et al (1994), from the luminosity at 2500Å an α ox =1.47 would be expected. Here a H 0 =50 km s −1 Mpc −1 was used to be consistent with Wilkes et al 1994. This is in agreement with the RASS value.…”

Section: Spectral Energy Distributionmentioning

confidence: 88%

RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

Grupe

Thomas

Leighly

2001

A&A

View full text Add to dashboard Cite

show abstract

“…Avni & Tananbaum 1982Chanan 1983;Kriss & Canizares 1985;Anderson & Margon 1987;Wilkes et al 1994;Yuan et al 1998;Vignali et al 2003;Strateva et al 2005; S06; J07; see also La Franca et al 1995, who found β ∼ 1). For the best-fit parameters using OLS(Y|X) (i.e.…”

Section: Discussionmentioning

confidence: 93%

“…; Kriss & Canizares 1985;Avni & Tananbaum 1986;Wilkes et al 1994 andYuan et al 1998). For comparison with S06 and J07, we perform the EM regression method and the best-fit parameters for the α ox − L 2 keV relation (i.e.…”

Section: α Ox Vs L 2 Kev and Vs Redshiftmentioning

confidence: 99%

The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS

Lusso

Comastri

Vignali

et al. 2010

A&A

360

284

View full text Add to dashboard Cite

We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 < z < 4.25) and X-ray luminosities (40.6 ≤ Log L [2−10] keV ≤ 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable photometric redshift and are classified as type 1 AGN on the basis of their multi-band Spectral Energy Distributions. We discuss the relationship between UV and X-ray luminosity, as parameterized by the α ox spectral slope, and its dependence on redshift and luminosity. We compare our findings with previous investigations of optically selected broad-line AGN (mostly from SDSS). A highly significant correlation between α ox and L 2500 Å is found, in agreement with previous investigations of optically selected samples. We calculate bolometric corrections, k bol , for the whole sample using hard X-ray luminosities (L [2−10] keV ), and the Eddington ratios for a subsample of 150 objects for which black hole mass estimates are available. We confirm the trend of increasing bolometric correction with increasing Eddington ratio as proposed in previous works. A tight correlation is found between α ox and k bol , which can be used to estimate accurate bolometric corrections using only optical and X-ray data. We find a significant correlation between α ox and Eddington ratio, in which the ratio between X-ray and optical flux decreases with increasing Eddington ratio.

show abstract

“…Such a QSO would have which would a ox B 1.0, be near the extreme of X-ray loudness among QSOs (Wilkes et al 1994). Thus, we regard the absence of a suitable optical counterpart for RX/AX J2229.0]6114 as somewhat discouraging an AGN classiÐcation unless it is a new type of extreme c-ray quasar (see°4).…”

Section: Ha Imagingmentioning

confidence: 99%

A Possible X‐Ray and Radio Counterpart of the High‐Energy Gamma‐Ray Source 3EG J2227+6122

Halpern

Gotthelf

Leighly

et al. 2001

ApJ

View full text Add to dashboard Cite

The identity of the persistent EGRET sources in the Galactic plane is largely a mystery. For one of these, 3EG J2227]6122, our complete census of X-ray and radio sources in its error circle reveals a remarkable superposition of an incomplete radio shell with a Ñat radio spectrum and a compact, powerlaw X-ray source with photon index ! \ 1.5 and with no obvious optical counterpart. The radio shell is polarized at a level of^25%. The anomalous properties of the radio source prevent us from deriving a completely satisfactory theory as to its nature. Nevertheless, using data from ROSAT , ASCA, the VLA, and optical imaging and spectroscopy, we argue that the X-ray source may be a young pulsar with an associated wind-blown bubble or bow-shock nebula and an example of the class of radio-quiet pulsars that are hypothesized to comprise the majority of EGRET sources in the Galaxy. The distance to this source can be estimated from its X-ray absorption as 3 kpc. At this distance, the X-ray and c-ray luminosities would be B1.7 ] 1033 and B3.7 ] 1035 ergs s~1, respectively, which would require an energetic pulsar to power them. If, on the contrary, this X-ray source is not the counterpart of 3EG J2227]6122, then by process of elimination the X-ray luminosity of the latter must be less than 10~4 of its c-ray luminosity, a condition not satisÐed by any established class of c-ray source counterpart. This would require the existence of at least a quantitatively new type of EGRET source, as has been suggested in studies of other EGRET Ðelds.

show abstract

The Einstein database of IPC x-ray observations of optically selected and radio-selected quasars, 1.

Cited by 202 publications

References 24 publications

RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS

A Possible X‐Ray and Radio Counterpart of the High‐Energy Gamma‐Ray Source 3EG J2227+6122

Contact Info

Product

Resources

About