K1 Q0957+561: Die historisch erste Linse mit Quasar
the web site for the CfA-Arizona Space Telescope LEns Survey of gravitational lenses.
Provides information and data on gravitational lens systems,
including HST and radio images that can be downloaded from this HTML site.
Autoren: C.S. Kochanek, E.E. Falco, C. Impey, J. Lehar, B. McLeod, H.-W. Rix.
Here is a summary of Q0957+561 observations. Position separations
are given in arcseconds. Values from this survey will appear in red. Other values (such as radio data) were obtained
from the literature.
|Data from Castles|
Click on images for full size version.
Summary of Multiply Imaged Systems
Double Quasar QSO 0957+561 A,B — time delay DtA,B = 416 d|
||Authors: S. Refsdal, R. Stabell, J. Pelt, R. Schild|
||Journal-ref: A&A 360 (2000) 10 [astro-ph/0005371 ]|
||Title: Constraints on source and lens parameters from microlensing variability in QSO 0957+561 A,B|
From regular monitoring of the Double Quasar QSO 0957+561 A,B there is
now general agreement on a time delay of about 416 days. This has made
it possible to determine the microlensing residual in the light-curve,
see Pelt et al. (1998). We have used two significant microlensing
• 1) A "quiet" period with a variability less than 0.05 mag
lasting about 8 years, and
• 2) A change in the residual of 0.25 mag
during a time interval of about 5 years.
The first feature gives a lower limit for the lens mass, M, for a given normalized source radius, r,
whereas the second feature gives an upper limit. We have considered the
amount of mass in a continuum to be a free parameter with possible
values between 0% (all mass in lenses) and 90%.
At a significance level of 1% the mass can only be constrained within a rather wide range
For the radius R of the source an upper limit of 1016 cm is found,
whereas the normalized source radius r is restricted to be smaller than
30. At a level of 10%, however, the range of possible masses is much
narrower (2 × 10-3M to
0.5M), and the upper limit of R is about
6 × 1015 cm, whereas the value of r is restricted to be less than 2.
We have used an effective transverse velocity V equal to 600 km s-1.
The double quasar Q0957+561 A,B was the first discovered multiple image gravitational lens, the first to have a
measured time delay and to produce a gravitational lens determination of the Hubble parameter, and the first
system in which a microlensing effect was seen in the observational brightness record (Vanderriest et al. 1989).
This was not unexpected since such microlensing effects had already been predicted by Chang & Refsdal (1979),
see also Kayser et al. (1986), hereafter referred to as KRS, and Schneider & Weiss (1987).
With the time delay confirmed by the Vanderriest et al. report, Schild & Smith (1991) noted evidence for
fine structure in the microlensing light-curve. In this paper we do not concern ourselves with this reported
fine structure, and focus instead on the long-term microlensing trends.
Vanderriest et al. 1989 A&A 215, 1 [astro-ph/0102112 ]
The value of the time delay DtA,B = 415 d for Q0957+561
K2 UV variability of Q0957+561
Q0957+561 — z = 1.41 — DtA,B = 422.6 d —
MBH ~ 2.5 × 109M
— LX = 3.3 × 1045 erg s-1
||Authors: L.J. Goicoechea, V.N. Shalyapin, R. Gil-Merino, A. Ullán |
||Journal-ref: A&A (2008) [0810.4641 ]|
||Title: Structure function of the UV variability of Q0957+561|
We present a detailed structure function analysis of the UV variability of Q0957+561.
From new optical observations, we constructed normalized structure functions
of the quasar luminosity at restframe wavelengths of 2100 and 2600 Å. Old
optical records also allow the structure function to be obtained at 2100 Å,
but 10 years ago in the observer's frame.
These three structure functions are
then compared to predictions of both simple and relatively sophisticated
(incorporating two independent variable components) Poissonian models. We do
not find clear evidence of a chromatic mechanism of variability.
From the recent data, 100-d time-symmetric and 170-d time-asymmetric flares are
produced at both restframe wavelengths. Taking into account measurements of
time delays and the existence of an EUV/radio jet, reverberation is probably
the main mechanism of variability. Thus, two types of EUV/X-ray fluctuations
would be generated within or close to the jet and later reprocessed by the
disc gas in the two emission rings. The 100-d time-symmetric shots are also
responsible for most of the 2100 Å variability detected in the old experiment.
However, there is no evidence of asymmetric shots in the old UV
variability. If reverberation is the involved mechanism of variability, this
could mean an intermittent production of high-energy asymmetric fluctuations.
The old records are also consistent with the presence of very short-lifetime
(10 d) symmetric flares, which may represent additional evidence of time
evolution. We also discuss the quasar structure that emerges from the
The first lensed quasar Q0957+561 (Walsh et al. 1979) is probably the best-studied lens system. This has
been investigated in several spectral regions, including radio, IR, optical,
UV and X-ray wavelengths. The radio maps of both components showed the presence of radio cores and ~0.''1 jets
(Porcas et al. 1981). Hutchings (2003) reported evidence for EUV (~ 1100 Å) activity along the radio jets.
Apart from EUV emission associated with the jet, Hutchings (2003)
also found EUV emission within a radius of 0.''3, which is associated
with a circumnuclear environment. Taking into account
the redshift of the quasar (z = 1.41), optical observations in the
g and r bands correspond to middle ultraviolet (MUV) emission (~ 2100-2600 Å).
Hence, fluctuations in the observed optical
magnitude trace variations in the UV luminosity of the
source. Q0957+561 is a very bright and massive object, with
both lLl (1350Å) and
1046 erg s-1, and a
black-hole mass of
MBH ~ 2-3 × 109M
(Peng et al. 2006). The double quasar Q0957+561 is also a X-ray bright source (e.g. Chartas
2000), but a possible X-ray jet has not yet been resolved.
Chartas, G. 2000, ApJ 531, 81 [astro-ph/9910299 ]
X-Ray Observations of Gravitationally Lensed Quasars: Evidence for a Hidden Quasar Population
Hutchings, J.B. 2003, AJ 126, 24
Oscoz A., et al., 2001, ApJ 552, 81 [astro-ph/0102112 ]
Time Delay in QSO 0957+561 From 1984-1999 DtA,B = 422.6 d
Peng, C.Y., et al. 2006, ApJ 649, 616
Porcas, R.W., Booth, R.S., Browne, I.W.A., Walsh, D., & Wilkinson, P.N. 1981, Nature 289, 758
Shalyapin, V.N., et al. 2008, A&A, [0810.4619 ]
Q0957+561: time delays and the origin of intrinsic variations
Walsh, D., Carswell, R.F., & Weymann, R.J. 1979, Nature 279, 381
K3 Gravitationally Lensed Quasar Hosts
| — |
||Authors: Peng, C.Y.; Impey, C.D.; Rix, H-W.; Kochanek, C.S.; Keeton, C.R.; Falco, E.E.; Lehár, J.;
||Journal-ref: ApJ 649 (2006) 616 [astro-ph/0603248 ]|
||Title: Probing the Coevolution of Supermassive Black Holes and Galaxies Using Gravitationally
Lensed Quasar Hosts|
In the present-day universe, supermassive black hole masses (MBH) appear to be strongly
correlated with their galaxy's bulge luminosity, among other properties.
In this study we explore the analogous relationship between MBH, derived
using the virial method, and the stellar R-band bulge luminosity
(LR) or stellar bulge mass (M*) at epochs of
1<~z<~4.5, using a sample of 31 gravitationally lensed AGNs and 20 non-lensed AGNs.
At redshifts z>1.7 (10-12 Gyr ago), we find that the
observed MBH-LR relation is nearly the same
(to within ~0.3 mag) as it is today. When the observed LR are
corrected for luminosity evolution, this means that the black holes grew
in mass faster than their hosts, with the
MBH/M* mass ratio being a factor of
>~4+2-1 times larger at z>1.7 than it is
today. By the redshift range 1<~z<~1.7 (8-10 Gyr ago), the
MBH/M* ratio is at most 2 times higher
than today, but it may be consistent with no evolution. Combining the
results, we conclude that the ratio
MBH/M* rises with look-back time,
although it may saturate at ~6 times the local value. Scenarios in which
moderately luminous quasar hosts at z>~1.7 were fully formed bulges
that passively faded to the present epoch are ruled out.
|Literatur zu ""|
|S. Refsdal, R. Stabell, J. Pelt, R. Schild||2000||A&A 360, 10||
|H. Heintzmann||( Eintrag vom 25.10.2008) ||
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