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Notes for object [HB89] 0420-014

12 note(s) found in NED.


1. 2005AJ....130.1418J
Re:[HB89] 0420-014
The parsec-scale jet of this quasar is strongly dominated by the VLBI
core, which has a complex polarization pattern (see Figs. 3 and 17),
implying multicomponent substructure in the core region. We detect
two moving components in the innermost part of the jet. Knot B1 has a
slower motion near the core, ~7c (Fig. 30), and accelerates
significantly beyond 0.2 mas as its trajectory turns from -100^deg^
to -175^deg^ (Fig. 18). The bright component B2 traced inside 0.15
mas from the core moves ballistically along {THETA} ~ -72^deg^ at an
apparent speed similar to that derived for B1 near the core. The
behavior of the knots is consistent with the common curved trajectory
for jet components found by Britzen et al. (2000).

2. 2005A&A...435..839T
Re:0420-014
4.3 Candidate inverted-spectrum sources
B0420-014: this source is also known as OA 129 and is a quasar (z =
0.915 from Peng et al. 2000) with a very high optical polarization of
ca 17 % (Wills et al. 1992). It is very variable both in the radio
(Peng et al. 2000) and in the optical wavelengths where the steepest
detected variation was 0.12 mag in 40 min (Villata et al. 1997). It has
also been detected in the {gamma}- and X-rays (Radecke et al. 1995).
.
The high-frequency outbursts of B0420-014 have been studied in detail
by Stevens et al. (1995). They used monitoring data from the James
Clerk Maxwell Telescope (JCMT), the Metsahovi Radio Observatory,
Institut de RadioAstronomie Millimetrique (IRAM) and the SEST to study
the evolution of the bursts at several frequencies between 22 GHz and
375 GHz. The behaviour of the flares was observed to be qualitatively
consistent with the shocked jet model by Marscher & Gear (1985).
.
The spectral shape is convex regardless of the intense variability on
both sides of the turn over (Var_{DELTA}S_(~5 GHz) = 4.73 and
Var_{DELTA}S_(90 GHz) = 8.12)

3. 2004ApJS..155...33S
Re:VSOP J0423-0120
In the USNO and VLBA2cm1 images there is additional emission south of
the core component.

4. 2003ApJ...589..126Z
Re:[HB89] 0420-014
3.4. B0420-014 No reliable fits to a {lambda}^2^ law were obtained for
this quasar. The plot of polarization angle versus {lambda}^2^ (inset to
Fig. 6a) is representative of the results obtained for B0420-014. Two
different RM slopes are implied: a steep positive slope from 15 to 12
GHz and a shallower and negative slope across the 8 GHz position angle
data. The spectral index plot (Fig. 6b) shows that a flat spectrum
characterizes most emission from this quasar across 8-12 GHz. Percent
polarizations m integrated over the source are 0.9%, 0.1%, and 0.4% at
8.1, 12.5, and 15 GHz, respectively. We set an upper limit to m of 0.2%
at 12.1 GHz. The upper limit for 12.1 GHz is due to noisier polarization
data at this frequency. RM fits using all but the 12.1 GHz data create
inconsistent slopes of position angle versus {lambda}^2^. The 8 GHz
points are consistent with an RM of zero, while the two points at 12.5
and 15.1 GHz suggest a much higher RM.

5. 2003AJ....126.2237D
Re:PKS B0420-014
.
4.8. Blazars
.
Blazars are common in the radio-excess sample; PKS 0235+164
(F02358+1623), PKS 0338-214 (F03384-2129), PKS 0420-014 (F04207-0127),
PKS 0537-441 (F05373-4406), PKS 0735+17 (F07352+1749), PKS 0754+100
(F07543+1004), PKS 0829+046 (F08291+0439), OJ 287 (F08519+2017),
PKS 1144-379 (F11445-3755), 3C 273 (F12265+0219), 3C 279
(F12535-0530), B2 1308+32 (F13080+3237), OQ 208 (F14047+2841), OQ 530
(F14180+5437), B2 1732+389 (F17326+3859), Q2005-489 (F20057-4858),
BL Lac (F22006+4202), and 3C 446 (F22231-0512). These BL Lac objects
are optically variable, flat radio spectrum quasars, or "transition
objects" between traditional BL Lac objects and (strong emission-line)
quasars. Many of the blazars have extremely high radio powers
[L_{nu}_(4.8 GHz) > 10^27^ W Hz-1] and FIR luminosities
[{nu}L_{nu}_(60 micron) > 10^13^L_solar_] and are at relatively large
redshifts (z > 0.9). Blazars also occur in the sample at lower
redshifts and powers, as low as z ~ 0.05 and L_{nu}_(4.8 GHz) ~ 10^25^
W Hz-1. All the known blazars in the radio-excess sample have large
radio excesses (u < -0.2), several with extreme values of u ~ -1.0.
CAB comment that the blazars in their full sample all have u < -0.15
and spectral indices between 1.4 and 4.8 GHz of less than 0.5. This
makes them flat spectrum objects with large radio excesses.

6. 2002ApJS..140..143B
Re:[HB89] 0420-014
q0420-0127, z = 0.915.-PKS. This is a well-studied quasar, with an
optical absorption line spectrum reported by Aldcroft et al. (1994).
G270.

7. 2001ApJS..134..181J
Re:[HB89] 0420-014
0420-014 (OA 129). - Wagner et al. (1995) found that this quasar
exhibits pronounced flares at optical frequencies. They noted that the
optical light curve is consistent with the assumption of repeated outbursts
at 13 month intervals and suggested that the flares are caused by knots of
enhanced particle density propagating along a helical trajectory in a
precessing jet. At kiloparsec scales the source has structure directly to
the south out to 25" and a weak secondary component ~20" northeast of the
core (Antonucci & Ulvestad 1985). Britzen et al. (2000) investigated
the VLBI structure at 3.6 cm between 1989.32 and 1992.48 and found five jet
components that move at apparent superluminal speeds of 13.8, 7.4, 5.0,
3.8, and 2.1 h^-1^ c, decreasing as a function of distance from the core.
Hong et al. (1999) reported two superluminal components with apparent
velocities of 1.9 +/- 0.6 and 3.4 +/- 0.9 h^-1^ c at 5 GHz.
At 43 GHz the source consists of a broad jet to the south, with a flare
to the southwest between 1.5 and 2 mas of the core, similar to the
structure found at 15 GHz by Kellermann et al. (1998). A weak feature
(component C2; Fig. 6a) to the southwest appears to be a stationary knot.
Another, more prominent stationary component (C1) is closer to the core.
During 1996 the model fits reveal motion of component B at
6.2 +/- 0.6 h^-1^ c toward C1, after which the two merge in 1997.58.
Fig. 6b shows the images at the last four epochs on a scale that
accentuates the region near the core where component B appears.

8. 2001ApJ...548..200X
Re:PKS 0420-01
3.3. PKS 0420-014
This quasar has revealed a strong variability in the optical band
(Webb et al. 1988). A noticeable flare was detected in late 1979, when a
1.3 mag increase in 5 days was registered, followed by a 1.7 mag decrease
in 23 days (Villata et al. 1997). A strong variability also comes out from
the 20 yr light curve (from 1970 to 1990) reported by Smith et al. (1993).
Wagner et al. (1995) noticed flux variations with timescales of the order
of 110 days. The flare of 1992 February-March was the highest optical state
observed until then (R = 14.6 mag); in that period EGRET registered the
highest {gamma}-ray flux density. Since low fluxes or nondetections at
{gamma}-ray energies correspond to low optical states, a direct correlation
between the optical and {gamma}-ray emission was suggested. The most
noticeable variation was a fall of 2.64 mag in 40 days observed from
1995 September 15 to October 25 in the R band (Villata et al. 1997). The
fastest one detected was {DELTA}R = 0.12 mag in 40 minutes (Villata et al.
1997); it is a microvariability. During our observational period, the
maximum variation of the source was an increase of {DELTA}R = 0.83 mag in
16.5 minutes on 1999 January 17 (see Table 2, Fig. 5), while the perfect
light curve was detected on 1999 January 24 (shown in Fig. 6). Figure 6
shows the source decrease 0.62 mag within 49 minutes and a subsequent
increase of 0.41 mag in 26.6 minutes in the R band. After that, the quasar
luminosity rapidly decreased down to R = 18.32 in 24.5 minutes. This is
the lowest state registered up to now. We have examined the CCD brightness
measurements of our field comparison stars 4 and 8, respectively. The
maximal deviation for one night is 0.06 and 0.12 mag, respectively. So we
infer that the time evolution of the standard stars should not cause
errors of more than 12%.

9. 2000A&AS..145....1P
Re:[HB89] 0420-014
0420-014: In this quasar (z=0.915), two outbursts cover the whole
monitoring period at all observing wavelengths. Its modulation index
decreases firstly from 11.5% at 6 cm to 9.3% at 2.8 cm, then increases
to 12.9% at 1.3 cm;

10. 1998A&AS..131..451R
Re:[HB89] 0420-014
This source is a radio-loud flat-spectrum AGN and also classified as a
Blazar. It has been detected in {gamma} and X-rays (Radecke et al.
1995), and has a very high optical polarization of ~17% (Wills et al.
1992). At mas resolution the source shows a symmetrical unresolved core.
This is the case of either a "naked" core or that of a jet aligned very
close to the line of sight (Wehrle et al. 1992). At {lambda}7mm the
source consists of a core and a pronounced bent jet (Krichbaum et al.
1994a). We found fringes to the source in 1990 for one scan which was
not enough to make a hybrid map but sufficient to make a fit to the UV
data. The result of the model fit is presented in Table 7.
Comparing with the Flux_SD_ (Table 2), it is clear that more than 50% of
the flux density is missing. With so few uv points covering such a short
time it is difficult to make any statements about the source structure,
but it is clear that this source is observable at {lambda}3mm, and
warrants further observations.

11. 1997A&AS..121..119V
Re:PKS 0420-01
3.2. PKS 0420-014
This quasar has revealed a strong variability in the optical band. Webb et al.
(1988) present its light curve from April 1969 to January 1986: the source is
very active and exhibits variations up to 2 mag on a few year time scale. A
noticeable flare was detected in late 1979, when a 1.3 mag increase in 5 days
was registered, followed by a 1.7 mag decrease in 23 days. A strong variability
also comes out from the 20 year light curve (from 1970 to 1990) reported by
Smith et al. (1993). Their data, in the photographic band, show a maximum
magnitude variation of 2.8 and three maxima at the beginning of 1975,1978, and
1982. Other three maxima were observed at the beginning of 1990, 1991, and 1992
by Wagner et al. (1995), who also noticed fast flux variations with time scales
of the order of 1-10 days. The flare of February-March 1992 was the highest
optical state observed until then (14.6 mag in the R band); in that period
EGRET registered the highest {gamma} flux density. Moreover, since low fluxes
or non detections at {gamma} energies correspond to low optical states, a
direct correlation between the optical and {gamma} emissions was suggested.
We have no calibration of the field comparison stars of this source;
consequently, in Tables 8-10 and in Figs. 3-5 the source magnitude is given as
the deviation from the minimum value registered during the monitoring period.
Our data confirm the strong variability; the most noticeable variation was the
fall of 2.64 mag in 40 days observed from September 15 to October 25, 1995 in
the R band. A rough calibration leads to the estimate R=14.2 for the peak
registered on September 15, 1995 (JD^bar^=975.6), which would thus represent
the highest optical state ever seen.
We also checked for microvariability in the R band on October 25-26, 1995
(JD^bar^=1016): the steepest variation detected was 0.12 mag in 40 minutes (see
Fig. 5).

12. 1994ApJS...93....1A
Re:PKS 0420-01
Q0420-0127 (PKS 0420-01, z_em_ = 0.915)
Wills et al. (1980) observed this object in the approximate range 3650
- 6700A and found an Mg II system at z_abs_=0.633, but they
give no quantitative treatment of the spectrum. Yanny (1992) presents
narrow band [O II] {lambda}3727 photometry of this field and finds
at least 7 nearby candidate emission line objects. Yanny & York
(1992) take this and similar objects as evidence favoring the
disappearing starburst or merging dwarf scenario at z > 0.5. We
confirm the z_abs_=0.633 system and find no new absorbers in our
spectrum.


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