|Frankfurt Quasar Monitoring|
1424+240, TXS 1424+240, B2 1424+24, OQ+240
KUV 14247+2401, 7C 1424+2401, QSO B1424+240
PKS 1424+240, RGB J1427+238, 2E 1424.7+2401
SDSS J142700.39+234800.0, GB6 B1424+2401
FBQS J142700.4+234800, RX J1427.0+2348
0FGL J1427.1+2347, RBS 1395, 1424+240
|Equat. coordinates||RA 14 27 00.5 DE +23 48 00 (J2000)|
|Redshift||z=0.160 (2) / z>0.603 (5)|
|Total mag range (mv) (4)||14.0 - 18.39|
|Catalog Magnitude (1)||14.28|
|Absolute Magnitude (1)||---|
× 109 yrs
/ >5.5 × 109
1424+240 is a variable
in Bootes, about 1° NE of Arcturus. The
refers to the
Parkes Radio Survey (PKS),
where this object was cataloged
as a radio source in 1973. PKS
was discovered as a radio loud point source by the Ohio Radio Survey
it was identified with
stellar object by the Palomar-Green
Bright Quasar Survey (PG),
where this object
was initially classified as a white dwarf due to its featureless
spectrum. In the 1980s, it
was finally identified
as an extragalactic object. PKS
1424+240 was classified as
a BL Lac object in
the 1990s, after X-ray observations were carried out by ROSAT.
Due to the featureless spectrum no accurate redshift has been determined to date. CDS Strasbourg Database, as well as NASA/IPAC Extragalactic Database, published a (tentativ) redshift of z=0.16 (Aleksić et al. 2011), which is not fully accepted by Véron-Cetty et al. 2001-2010. A recent spectroscopic study found a new redshift lower limit of z>0.6035 (Furniss et al. 2013). This would make PKS 1424+240 the most distant TeV-emitting Blazar ever detected. However, the true distance as well as the absolute luminosity still remain uncertain.
PKS 1424+240 displays large and rapid changes in optical brightness with a total range of about 4 magnitudes. Usually, it is a bright object of about 14 mag. Visual observers need at least an 8- to 10-inch telescope to glimpse this stellar object during bright state. CCD observers, as well as visual observers, shall use the comparison stars given above.
Looking at some interesting objects around PKS 1424+240, we first take a look at RX Boo, a type RR Crb variable some 2° NE, ranging between 8.6-11.3 mag (340d, M6.5-M8).
Another extragalactic variable object is NGC 5548, a well known AGN, some 2.4° to the NW. This type 1 Seyfert galaxy shows a total optical variability ranging between 11.9 mag and 14.3 mag.
Some 12° NNE of PKS 1424+240, bright 14-mag quasar MRK 478 might also attract your interest.
And finally, two other bright 15-mag quasars are located nearby: MRK 813 can be found about 4° to the south, and PG 1402+261 lies about 5.4° to the west.
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