Date and Time of the Query: 2022-01-27 T01:00:45 PST
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Notes for object WISE J050925.96+054135.3

3 note(s) found in NED.

1. 2008ApJS..175..314D
Re:VSOP J0509+0541
J0509+0541.-The core is <0.4 mas in size. The extended emission to the south and
east is seen in the VLBApls.

2. 2003AJ....125..572H
Re:PMN J0509+0541
This bright optical and X-ray emitter, thought to be the counterpart of
GEV J0508+0540 in the GeV catalog of Lamb & Macomb (1997), is a source of
significant numbers of photons above 1 GeV, even though it did not meet the
threshold for inclusion in 3EG. It is most notable as the source of two
{gamma}-rays above 40 GeV (Dingus & Bertsch 2001) and the only blazar to be
detected at these energies. We have obtained several optical spectra, which
are all featureless. No redshift has been determined. The broad undulations
and apparent discrete features in the spectrum shown in Figure 2 are
artifacts of variable instrument focus that affect flux calibration.
Galactic extinction in this direction is E(B-V) = 0.13 according to
Burstein & Heiles (1982) or E(B-V) = 0.11 according to Schlegel et al.
(1998). We also obtained an I-band CCD image in seeing of 0.68" on the MDM
2.4 m telescope (not shown) in order to search for any evidence of a host
galaxy; none was seen.

3. 2001ARep...45...79C
Re:ZS 0506+056
0509+0541 (0506+056)
We observed this source with the RATAN-600 telescope in eight runs at
3.9 and 7.5 GHz in 1980-1991. The highest flux density,
S_(3.9)_ = 894 +/- 29 mJy and S_(7.5)_ = 895 +/- 65 mJy, was recorded in
October 1984, and the lowest flux densities, in August 1991, were
S_(3.9)_ = 450 +/- 25 mJy and S_(7.5)_ = 420 +/- 22 mJy (rms errors are
quoted here). The weighted average flux densities, <S>, during our
observations were 536 and 531 mJy, respectively, at 3.9 and 7.5 GHz. The
variability index for 1984-1991, V = dS/<S>, derived taking into account
individual errors as described in [1, 13], was 0.5 at both frequencies.
Starting in 1996, we observed the source at six frequencies. In 1999,
we included it in our program to search for flux density variability on
short time scales, and it was observed daily for 100 days starting on
May 22, 1999. Figure 1 shows the radio spectra of the source for August
1997 and July 1999. The substantial variability at low frequencies
(0.97 and 2.3 GHz) is striking. This source has a small extended component,
while its compact component makes the main contribution to its radiation.
In the August 1997 spectrum, the peak flux density is at about 12 GHz. The
source was in a more active state in 1999; its peak flux density shifted
toward higher frequencies and the spectrum could be approximated with a
logarithmic parabola, logS = 2.727 + 0.173 log{nu} - 0.044 log^2^{nu},
where the flux density is in mJy and the frequency in GHz. During this
interval, the source showed variability at 3.9 and 2.3 GHz on time scales
less than ten days, as well as cyclic variability with a 52 day
quasi-period at the same frequencies (and possibly also at 7.7 GHz). The
cyclic variability at the different frequencies is correlated.
The source was not resolved with the VLA B [14]. In [14], it was
identified with a star-like object with magnitudes 16^m^ and 15.5^m^ on
the POSS O and E prints. In 1992, at our request, the object's spectrum
was taken with the 6-m telescope of the Special Astrophysical Observatory
[15], and it was tentatively identified as a BL Lac object. The optical
spectrum in Fig. 1 obtained on March 15, 1999 with an exposure time of
40 min shows a featureless continuum, supporting this identification.

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