NGC 821 is an elliptical galaxy in the constellation Aries. It is estimated to be about 80 million light-years from the Milky Way [ 3 ] and has a diameter of approximately 55,000 light years. NGC 821 was discovered on September 4, 1786, by astronomer Wilhelm Herschel .

NGC 821 是 白羊座 的一個 星系。

NGC 821 是 白羊座 的一個 星系。

NGC 821 is a Elliptical Galaxy in the Aries constellation. NGC 821 is situated close to the celestial equator and, as such, it is at least partly visible from both hemispheres in certain times of the year.

2004年10月6日 · We report the results of the Chandra ACIS-S observations of the elliptical galaxy NGC 821, which harbors a supermassive nuclear black hole (of 3.5x10^7 solar masses), but does not show sign of AGN...

2010年8月13日 · NGC 821 becomes the most distant galaxy with a PNLF distance determination. The PNLF distance modulus is smaller than the surface brightness fluctuation (SBF) distance modulus by 0.4 mag. Our kinematic information permits to rule out the idea that a shorter PNLF distance could be produced by the contamination of the PNLF by background galaxies ...

2004年5月18日 · We report the results of the {\it Chandra} ACIS-S observations of the elliptical galaxy NGC 821, which harbors a supermassive nuclear black hole (of $3.5 \times 10^7 M_{\odot}$), but does not show...

NGC 821是白羊座的一个星系。 弗里德里希·威廉·赫歇尔于1786年9月4日发现此星系。

NGC 821 -- Active Galaxy Nucleus Candidate The astronomical object called NGC 821 is a Active Galaxy Nucleus Candidate: Origin of the objects types : (Ref) Object type as listed in the reference "Ref" (acronym) Object type linked to the acronym according to the original reference Anterior to 2007, before we can link the objet type to a ...

ngc 821 是白羊座的一个星系。 维基共享资源上的相关多媒体资源：ngc 821. ned – ngc 821; seds – ngc 821; simbad – ngc 821; vizier – ngc 821