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Notes for object ABELL 2218

9 note(s) found in NED.


1. 2007MNRAS.376.1073Z
Re:ABELL 2218
Abell 2218. This is among the best-studied clusters in the sky, and is
particularly popular for studies of gravitational lensing. In fact, one of the
candidates for the highest redshift source (z [IMAGE] 7) known is in this
cluster field (Kneib et al. 2004a).
Kneib et al. (2004b) present the discovery of SMM J16359+6612, a high
redshift, lensed submm galaxy. This source is present in our maps, but because
Kneib et al. (2004b) use a smaller pixel size, more structure is evident in
their maps. This cluster is not used in our final SZ sample because the lensed
source is too complex to model and remove from the data.
At wavelengths close to SCUBA's, Sheth et al. (2004) discuss the detection of
CO from SMM J16359+6612, and Biviano et al. (2004) present an ISOCAM study of
star-forming galaxies in Abell 2218. Egami et al. (2005) present Spitzer
observations of this cluster as well. Cooray et al. (1998) list radio point
sources at 28.5 GHz in this cluster.
Abell 2218 was also a popular target for early searches for the SZ effect
like that presented in Radford et al. (1986) and culminating in work like that
in Jones et al. (1993). More recently, this cluster has been imaged by the
Effelsberg 100-m telescope at 10 GHz (Uyaniker et al. 1997), the Nobeyama
telescope at 36 GHz (Tsuboi et al. 1998), SuZIE II (Benson et al. 2004), the
Ryle telescope (Jones et al. 2005) and OVRO/BIMA around 30 GHz (Grego et al.
2001; Reese et al. 2002; LaRoque et al. 2006). It is not obvious that this
cluster is a particularly good target for SZ observations above these
frequencies due to SMM J16359+6612.
Recent X-ray studies of this cluster include Machacek et al. (2002) using
Chandra and Pratt, Bohringer & Finoguenov (2005) using XMM-Newton.

2. 2007ApJ...655...30V
Re:ABELL 2218
Abell 2218 is a well-studied, very rich cluster at z = 0.1756 (Le Borgne et al.
1992). Its FP has been analyzed in two independent studies, Jorgensen et al.
(1999) and Ziegler et al. (2001). Jorgensen et al. (1999) give velocity
dispersions and two sets of structural parameters, one derived from HST images
and one derived from ground-based data. Their velocity dispersions have already
been corrected to the 1.7" aperture at the distance of Coma. The ground-based
structural parameters were corrected from the observed I_c_ band to the
rest-frame B band using the listed V - I colors: B_z_ = I_c_ + 1.29 (V-I_c_) +
0.18, and corrected from <{mu}>_e__e_ to {mu}_e_. The structural parameters
measured from the HST F702W images were transformed by Jorgensen et al. (1999)
to the I_c_ band, and we use equation (A3) to transform the surface brightness
to rest-frame B.
Ziegler et al. (2001) obtained independent spectroscopy for galaxies in
Abell 2218 and give velocity dispersions that were corrected to the same 1.7"
radius aperture at the distance of Coma as we use. They used the same HST
imaging as Jorgensen et al. (1999) but derive their own structural parameters
from the images. We transformed their listed rest-frame Gunn r surface
brightnesses from L_{sun}_ pc^-2^ to mag arcsec^-2^ using their equation (7) and
then converted them back to observed I_c_ magnitudes using their equation (1).
In this conversion we used the listed V and I_c_ magnitudes after applying
extinction corrections^ ^of 0.083 mag in V and 0.048 mag in I_c_. The I_c_
surface brightnesses were transformed from <{mu}>_e_ to {mu}_e_ and corrected to
rest-frame B using equation (A3).
Combining all information, there are three measurements of the FP: (1)
dispersions and HST structural parameters from Jorgensen et al. (1999), (2)
dispersions and ground-based structural parameters from Jorgensen et al.
(1999), and (3) dispersions and HST structural parameters from Ziegler et
al. (2001). The two sets of dispersions and the two sets of ground-based
data are independent. We determined the M/L offset for all three cases and
compared the results. The offsets agree very well: differences are
approximately 0.02 in log(M/L_B_). Rather than take the average of the
three determinations, we use the zero point from measurement 2: it falls
between the other two and is the one used in the analysis of the
Jorgensen et al. (1999) paper. Apart from a systematic uncertainty of 0.02
due to the differences between the three determinations, there is also an
uncertainty introduced by the fact that all structural parameters were
measured in redder bands than the redshifted B band. This uncertainty
stems from color gradients and the dependence of the FP parameters on
passband and is estimated at 0.05 mag. The combined systematic uncertainty
is 0.029 in log(M/L_B_).

3. 2005MNRAS.359..417S
Re:ABELL 2218
A 2218 - The model of A 2218 builds on the models published by Kneib et
al. (1995, 1996) and incorporates for the first time the spectroscopic
redshifts of the M2 (Ebbels et al. 1998) and M3 (Ellis et al. 2001)
multiple-image systems. In addition to the central cluster-scale mass
component (A 2218 #1), this model contains a second cluster-scale mass
component (A 2218 #2) centred on the second brightest cluster galaxy which
lies to the south-east of the BCG. The velocity dispersion and cut-off
radius of the two bright cluster galaxies (A 2218 #3 and 4) that lie
adjacent to the M0 multiple-image system are also included as free
parameters.

4. 2005MNRAS.357..518J
Re:ABELL 2218
3.8 A2218 A2218 was the first cluster to be observed in the RT SZ programme
(Jones et al. 1993), and has also been extensively observed in many wavebands,
with SZ detections in the radio (e.g. Birkinshaw & Hughes 1994) as well as
strong and weak lensing observations (e.g. Kneib et al. 1995 and Squires et al.
1996) and X-ray studies (e.g. Markevitch 1997). We have previously reported a
measurement of H_0_ from this cluster (Jones 1995); we re-analyse our data here
because we have improved our source-subtraction and modelling techniques, and
because a new temperature measurement from ASCA is available that supersedes the
previous GINGA measurement.

5. 2005ApJ...624..606J
Re:ABELL 2218
A2218 (z = 0.18): A2218 looks fairly relaxed and symmetric except for a
slightly offset core and some very small scale core structure. Govoni et al.
(2004) find an asymmetric temperature structure, and they suggest that this
cluster is a late-stage merger. This cluster had three observations in the
archive, including two short observations at a focal plane temperature of
-110^deg^C and a longer observation at -120^deg^C. We used only the last
observation, which had more than double the exposure time of the other two.
The 0.5 Mpc aperture fell on three of the ACIS-I CCDs.

6. 2002ApJ...576..688B
Re:ABELL 2218
A2218.-There is evidence of soft excess emission at the level of ~20%
in the PSPC observation of this very rich, z = 0.171 cluster.

7. 2001ApJ...548..639K
Re:ABELL 2218
A2218. - This fairly small halo was first detected by Moffet &
Birkinshaw (1989). It is nearly unresolved in WENSS and is quite faint,
causing it to be missed by our survey, but we include it here for the sake
of completeness. This was the only halo or relic found in the literature
that was part of our initial sample but that we failed to detect in the
WENSS.

8. 2000NewA....5..335G
Re:ABELL 2218
A 2218. We confirm the existence of the diffuse source found by Moffet
& Birkinshaw (1989). It is slightly displaced from the cluster center,
toward East (Fig. 7). In a deep image obtained by Zwaan et al. (2000)
the diffuse source is more extended, with radio emission of very low
surface brightness also to the West of the cluster center. This halo
source is smaller than typical cluster-wide radio halos. It is similar,
both in structure and in size, to the halo in A 1300
(Reid et al., 1999). As in the case of A 1300, the diffuse radio source
is located in the same direction as the extension of the cluster X-ray
emission detected by the ROSAT HRI (Markevitch, 1997).
At 5 GHz, the flux density of the halo is reported to be 0.6 mJy
(Partridge et al., 1987). Comparison of this flux with the present
measurement at 1.4 GHz provides a spectral index {alpha}^1.4^_5_ ~ 1.6,
which should however be taken cautiously since the two maps at the two
frequencies do not have matched Fourier coverage.

9. 1999NewA....4..141G
Re:ABELL 2218
A 2218. The existence of a small radio halo was reported by Moffet &
Birkinshaw (1989). Here, the diffuse source is barely visible to the SW
of the strongest radio source.


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