NGC 4565

From Wikipedia, the free encyclopedia
Jump to: navigation, search
NGC 4565
Needle Galaxy 4565.jpeg
NGC 4565 or Needle Galaxy
Observation data (J2000 epoch)
Constellation Coma Berenices
Right ascension 12h 36m 20.8s[1]
Declination +25° 59′ 16″[1]
Redshift 0.004103[1]
Helio radial velocity 1230 ± 5 km/s[1]
Distance 42.7 ± 12 Mly (13.1 ± 3.7 Mpc)[2]
53 ± 4 Mly (16.2 ± 1.3 Mpc)[3]
Type SA(s)b?[1]
Apparent dimensions (V) 15′.90 × 1′.85[1]
Apparent magnitude (V) 10.42[1]
Other designations
UGC 7772,[1] PGC 42038,[1] Caldwell 38
See also: Galaxy, List of galaxies

NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on spiral galaxy about 30 to 50 million light-years away[2] in the constellation Coma Berenices.

The 10th magnitude galaxy sits perpendicular to our own Milky Way galaxy and is almost directly above the North Galactic Pole (in the same way Polaris is located above the Earth's North Pole).

It is known as the Needle Galaxy for its narrow profile.[4] First spotted in 1785 by Sir William Herschel (1738–1822), this is one of the most famous examples of an edge-on spiral galaxy.[5] "Visible through a small telescope, some sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed."[4]

Characteristics[edit]

NGC 4565 is a giant spiral galaxy more luminous than the Andromeda Galaxy[6] and it has been proposed that if it were viewed face-on, it would be the most spectacular of the galaxies of its type in the nearby Universe.[7]

Much speculation exists in the literature as to the nature of the central bulge. In the absence of clear-cut dynamical data on the motions of stars in the bulge, the photometric data alone cannot adjudge among various options put forth. However, its exponential shape suggested that it is a barred spiral galaxy.[8] Subsequent studies with the help of the Spitzer Space Telescope not only confirmed the presence of a central bar but also showed a pseudobulge within it as well as an inner ring.[7]

NGC 4565 has at least two companion galaxies, one of which is interacting with it.[9]

It has a population of roughly 240 globular clusters, more than the Milky Way.[6]

NGC 4565 and apparently smaller NGC 4562. 24-inch telescope on Mt. Lemmon, AZ. Courtesy of Joseph D. Schulman

References[edit]

  1. ^ a b c d e f g h i "Results for NGC 4565". NASA/IPAC Extragalactic Database. Retrieved 2006-10-12. 
  2. ^ a b "Distance Results for NGC 4565". NASA/IPAC Extragalactic Database. Retrieved 2010-05-02. 
  3. ^ Jensen, Joseph B.; Tonry, John L.; Barris, Brian J.; Thompson, Rodger I.; Liu, Michael C.; Rieke, Marcia J.; Ajhar, Edward A.; Blakeslee, John P. (February 2003). "Measuring Distances and Probing the Unresolved Stellar Populations of Galaxies Using Infrared Surface Brightness Fluctuations". Astrophysical Journal 583 (2): 712–726. arXiv:astro-ph/0210129. Bibcode:2003ApJ...583..712J. doi:10.1086/345430. 
  4. ^ a b NGC4565 at http://apod.nasa.gov/apod/ap040409.html
  5. ^ Spiral Galaxy NGC 4565 at http://www.eso.org/gallery/v/ESOPIA/Galaxies/phot-24a-05.tif.html
  6. ^ a b Globular Cluster Systems in Galaxies Beyond the Local Group
  7. ^ a b Detection of a Distinct Pseudobulge Hidden Inside the ``Box-Shaped Bulge of NGC 4565
  8. ^ "Intermediate-band surface photometry of the edge-on galaxy NGC 4565" at http://www.iop.org/EJ/article/1538-3881/123/3/1364/201272.text.html
  9. ^ HALOGAS: H I Observations and Modeling of the Nearby Edge-on Spiral Galaxy NGC 4565

External links[edit]

Coordinates: Sky map 12h 36m 20.8s, +25° 59′ 16″