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Date and Time of the Query: 2022-01-18 T06:02:40 PST
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Notes for object 4C +15.05

9 note(s) found in NED.


1. 2008ApJS..175..314D
Re:VSOP J0204+1514
J0204+1514.-The core is <0.2 mas in size. The faint emission to the southeast is
in the opposite direction of most of the jet emission, but the source structure
evolution is complicated.

2. 2003ApJ...590..109S
Re:3EG J0204+1458
In addition to the likely association with J0204+1514, this source may
also incorporate flux from the flatter and more centrally placed radio
source J0205+1444.

3. 1998ApJ...507..706P
Re:MRC 0202+149
The source 0202+149 is a flat-spectrum radio quasar with a redshift of
0.833 (Stickel et al. 1996). Bondi et al. (1996), Padrielli et al.
(1986), and Romney et al. (1984) imaged this source with VLBI at three
epochs (1980 February, 1981 October, and 1987 November) at 1.7 GHz as
part of a campaign to study the structure of low-frequency variable
sources. They found that the structure of 0202+149 was well fitted by a
model with two components separated by ~3.4 milliarcseconds (mas) along
a position angle of ~ -71^deg^. The separation of the components did not
change significantly over the three epochs, although the low resolution
of the observations does not allow the authors to place a very strict
upper limit on the proper motion. They find that both components vary in
flux, the southeastern component brightens, and the northwestern
component fades over the three epochs. A 22 GHz VLBI observation by
Moellenbrock et al. (1996) measured a brightness temperature for
0202+149 in excess of the inverse Compton limit for synchrotron
radiation (10^12^ K), indicating the likelihood of relativistic beaming
in this source.
The separations from the core as a function of time that we measure
from our images are shown in Figures 7a and 7b for components C1 and C2,
respectively. By taking the weighted average of the velocities found
from separate fits to the 2, 8, and 15 GHz positions of C1, we calculate
an outward velocity of 0.11 +/- 0.88 h-1c for this component. Similarly,
we measure a velocity of -0.23 +/- 0.65 h^-1^c for component C2. Both of
these velocities are consistent with no motion, and the 1 {sigma} upper
limits are 0.99 and 0.42 h^-1^c for C1 and C2, respectively. Since the
measured positions are consistent with stationary components, we have
plotted the best fits to constant separation from the core in Figures 7a
and 7b. In Figure 7a the fitted separations are at successively greater
distances from the core as the frequency increases. This
frequency-dependent separation was also seen in 1156+295 (Paper II) and
has been noted by other authors (e.g., Biretta et al. 1986). It may be
due to gradients in magnetic field and electron density, which cause the
{tau} = 1 surface to move progressively inward at higher frequencies.
The frequency-dependent separation in Figure 7b appears to go in the
wrong direction, although the error bars on the 15 GHz points are such
that this separation is not significant.

4. 1998ApJ...507..706P
Re:MRC 0202+149
The VLBI observations of 0202+149 at 1.7 GHz presented by Bondi et al.
(1996) show a bright component about 3.4 mas from the core that can
probably be identified with our component C1. Although their three
measured positions are also consistent with the component having no
motion, their measured separation is about 1.4 mas closer to the core
than ours. If a fit is done to the Bondi et al. (1996) positions that
cover the time range 1980-1987, combined with our measured 2 GHz
positions that cover the time range 1989-1996, then a slightly
superluminal velocity of 1.8 +/- 0.5 h^-1^c is obtained. However, this
velocity comes entirely from the difference in separation between the
Bondi et al. (1996) points and our points, and each set of measurements
individually is consistent with no motion. We suspect that this velocity
may arise from frequency-dependent separation combined with systematic
differences between the two sets of observations, and we use only the
velocity obtained from fits to our actual measured component positions.
Component C2 also appears to be stationary at 0.41 mas from the core,
but this component is not present in the images from 1989 and 1991.
Either this component really is moving outward, or it may represent a
standing shock in the underlying flow that appeared in this location
sometime between 1991 and 1993. If this component were moving at its
2 {sigma} upper limit proper motion of 0.04 mas yr^-1^, then in 1991 it
could have been only 0.33 mas from the core and may have been unresolved
in these earlier images. The high 8 GHz core flux in the 1991 image may
support this. If this is so, then the velocity of C2 would actually be
around 1.0 h^-1^c.
The components in this source are stationary in position angle as well
as in radius. However, they have different position angles from each
other. The measured position angle of C1 is -53.0^deg^ +/- 0.9^deg^, and
that of C2 is -75.0^deg^ +/- 4.3^deg^. The average position angle of C1
from the observations presented by Bondi et al. (1996) is -71^deg^, with
no error bars given for the position angles. Their error bars are likely
to be quite large because of the large size and ellipticity of their
beams. If the difference between the Bondi et al. (1996) C1 position
angle and our C1 position angle is in fact significant, this would imply
motion of C1 from a position angle close to that of C2 to its present
position angle over the time between the Bondi et al. (1996)
observations and the present. This would imply motion of C1 at close to
its 1{sigma} upper limit velocity.

5. 1998AJ....115.1295K
Re:PKS 0202+14
0202+149.--The jet shows a nearly right-angle bend.

6. 1998AJ....115.1253P
Re:WGA J0204.8+1514
WGA J0204.8+1514.--This source, also known as 4C 15.05, has a radio flux above 3
Jy and was also previously observed by Stickel et al. (1996), who classified the
source as an AGN at z=0.833 based upon the identification of two lines as O II
{lambda}3727 and Ne I {lambda}3833. These lines are also present in our
spectrum, as are four others (Fig. 2). However, the redshift claimed by Stickel
et al. (1996) is likely incorrect, as all six lines cannot be accounted for if
the redshift is z=0.833. We believe that a better fit is obtained with a
redshift z=0.405. This object is also the likely counterpart of the EGRET
source 2EG J0204+1514 (Thompson et al. 1995; Mattox et al. 1997).

7. 1996ApJ...468..556S
Re:PKS 0202+14
0202+149.--The source has been imaged by Peacock et al. (1981), who find it to
be faint and pointlike, and by Fugmann & Meisenheimer (1988), who find it to be
pointlike with a possible faint envelope. This result is in agreement with the
morphology seen in our R-band image. Our infrared measurements show variations
by a factor of ~8 in 1 month; there are no plausible candidates in the infrared
image of the field to account for this change through photometric errors.
Therefore, the object is violently variable. The photometric colors in the
visible indicate a power law with index {alpha}=-2.3 (Fugmann & Meisenheimer
1988); the infrared colors indicate a power law with {alpha}=-2.5 both when the
source is faint and when it is bright. The two slopes agree within the errors;
although we do not have simultaneous data to allow constructing a single-epoch
spectral energy distribution, the constancy of the slope indicates that the SED
is a single steep power law. Such a SED is not compatible with a flatter
spectrum that is reddened. Extrapolated into the ultraviolet, the SED would not
be capable of photoionizing emission lines of large equivalent width. The
spectrum of the source (Fig. 1) shows narrow emission lines at z=0.833 and of
moderate excitation, consistent with this conclusion.

8. 1996A&A...308..415B
Re:4C +15.05
0202+149: well fitted by a two component model. The separation and dimensions
of the two components did not change significantly over the three epochs. On
the other hand, both components show strong (~40%) flux density variability.
The source is unresolved by the VLA at 1.4 GHz (Perley 1982) and by MERLIN at
408 MHz (Mantovani, private communication), but the VLBI map accounts only for
~50% of the flux density measured by the Effelsberg 100 m telescope. This
means that there must be an extended component on a scale of hundreds of mas
completely resolved by our observations.

9. 1994A&AS..105..211S
Re:[KWP81] 0202+14
The identification and magnitude were taken from Fugmann & Meisenheimer
(1988).


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