Rahul Sharma (Editor)

BL Lacertae

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Right ascension
  
22 02 43.3

Redshift
  
0.07

Type
  
BL Lac

Discovered
  
1929

Discoverer
  
Declination
  
+42° 16′ 40″

Distance
  
0.9 Gly (0.276 Gpc)

Apparent magnitude (V)
  
var. ~14 to ~17

Constellation
  

Similar
  
Markarian 421, Markarian 501, PKS 2155‑304, OJ 287, 3C 279

BL Lacertae or BL Lac is a highly variable, extragalactic AGN (active galactic nucleus or active galaxy). It was first discovered by Cuno Hoffmeister in 1929, but was originally thought to be an irregular variable star in the Milky Way galaxy and so was given a variable star designation. In 1968, the "star" was identified by John Schmitt at the David Dunlap Observatory as a bright, variable radio source. A faint trace of a host galaxy was also found. In 1974, Oke and Gunn measured the redshift of BL Lacertae as z = 0.07, corresponding to a recession velocity of 21,000 km/s with respect to the Milky Way. The redshift figure implies that the object lies at a distance of 900 million light years.

BL Lacertae Looking into the hottest cosmic hearth Max Planck Society

BL Lacertae is the original member of a type of blazar known as "BL Lacertae objects"; also termed simply "BL Lac objects". This class is distinguished by optical spectra devoid of the broad emission lines characteristic of quasars. On occasion, however, BL Lacertae has been observed to display weak emission lines.

BL Lacertae Instruments HRC

BL Lacertae changes in apparent magnitude over fairly small time periods between values of 14 and 17. Its location in the sky for epoch 2000.0 is at RA 22h 02m 43.3s, DEC +42° 16′ 40″.

BL Lacertae wwwdaviddarlinginfoimagesBLLacertaejpg
BL Lacertae Galaxies BL Lacertae

BL Lacertae David39s Astronomy Active Galactic Nuclei AGNs

References

BL Lacertae Wikipedia


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