2130+099

UGC 11763, also known as II Zw 136 and MRK 1513, is a bright AGN in south-western Pegasus, close to the constellation Equuleus. UGC 11763 was discovered in 1965 by Fritz Zwicky, who described this 14-mag compact galaxy as a "variable very blue spherical, very compact". Follow-up spectroscopic investigations in 1967 revealed a Seyfert 1-spectrum, which led to the classification as a Narrow-Line Seyfert 1-galaxy (NLS1). By the mid 1980s, this AGN was reclassified as a quasar (radio-quiet, low luminosity quasar). Since 2001, Véron-Cetty et al. have redetermined the absolute luminosity to -22.9 M_B, which does not meet their quasar classification criterion of -23.0 M_B any longer. But this AGN shows an optical variability by about 1 magnitude. So in this case, a strict classification of either QSO or AGN is difficult. The compact galaxy UGC 11763 was first catalogued as a blue (see colour chart above) and UV-bright object in 1973 by Markarian (MRK), then again in 1986 by the Palomar-Green Bright Quasar Survey (PG), and finally by the International Ultraviolet Explorer IUE in 1978-1980. In addition, the AGN was found to be an infrared source by IRAS in 1983, as well as an X-ray emitter later on (Exosat 1985, Einstein (2E), ROSAT (RX)).
UGC 11763 is a distorted spiral galaxy with a true diameter of 30 kpc, inclined 60° from face-on (see image above). The galaxy centre is dominated by a very bright and active nucleus. The peculiar ring-like spiral arm pattern is considered as a result of interaction with at least one companion galaxy and/or some kind of post merger state.

UGC 11763 is a weakly variable object with a total range of only about 1 magnitude (14.1-15.0 mag). Visual observers need at least an 8- to 10-inch telescope or larger to glimpse this stellar object. With large aperture telescopes UGC 11763 becomes more star-like, although it is quite difficult to recognize the galaxy disk as a very faint elongated halo around the prominent core. CCD observers, as well as visual observers, shall use the comparison stars given above. Other sequences were published by Miller (1981) and Penston et al. (1971).
A notice to the photometrists: Do not use comparison star #15. This star was recently found to be variable (probably type W UMa).

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Locating UGC 11763 is quite easy due to its proximity to Epsilon (8) Pegasi, only 2.9° W. One deep sky showpiece near UGC 11763 shall not be missed: globular cluster M15. This is one of the brightest globular clusters in the northern sky (6.2 mag) and is located only 2° N of UGC 11763. M15 appears bright and large with a very dense core. Inside M15, large aperture telescopes may reveal a very special object: Pease 1, a faint planetary nebula, only 3” in diameter

Stargazers who like to observe more very old quasi-stellar photons may turn to quasar 3C 304, a bright 14-mag object at the same distance as UGC 11763, located 11.7° ENE of UGC 11763.

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Link:

2130+099 (Sasmirala, Univ. of Heidelberg)

Cross-Identifications	II Zw 136, PGC 66930, MRK 1513, UGC 11763 QSO B2130+099, Zw II 2130+09, PG 2130+099 RX J2132.4+1008, SDSS J213227.81+100819.1 2XMM J213227.8+100819, [HB89] 2130+099 EUVE J2132+10.1, IRAS 21299+0954
Equat. coordinates	RA 21 32 27.8 DE +10 08 19 (J2000)
Constellation	Pegasus
Type (1)	AGN
Redshift	z=0.061 (1) (6)/ z=0.063 (2)
Distance (2) (3)	251 Mpc
Total mag range (mv) (4) (5)	14.1 - 15.0
Catalog Magnitude (1)	14.64
Absolute Magnitude (1)	-22.9 M_B
Light Travel-Time (2)	0.794 × 10⁹ yrs

star	B	V	R_c	I_c
3	16.109 (0.081)	15.394 (0.009)	14.978 (0.009)	14.656 (0.012)
4	16.183 (0.066)	15.201 (0.011)	14.735 (0.005)	14.399 (0.005)
9	15.708 (0.061)	14.741 (0.005)	14.266 (0.004)	13.864 (0.002)
10	15.381 (0.021)	14.494 (0.005)	14.069 (0.002)	13.684 (0.004)
11	17.235 (0.078)	16.038 (0.025)	15.480 (0.008)	14.987 (0.006)
13	14.831 (0.013)	13.848 (0.002)	13.328 (0.003)	12.928 (0.003)
15	13.758 (0.014)	13.079 (0.007)	12.722 (0.005)	12.443 (0.006)