NGC4535 and NGC4526 - Galaxies in Virgo
 

ngc4535 ngc4526 in LRGB

ngc4535 (bottom) and ngc4526 (top) - galaxies in Virgo

NGC 4535 is a barred spiral galaxy located some 54 million light years from Earth in the constellation Virgo. It is a member of the Virgo Cluster of galaxies and is located 4.3 from Messier 87. The galactic plane of NGC 4535 is inclined by an angle of 43 to the line of sight from the Earth. The morphological classification of NGC 4535 in the De Vaucouleurs system is SAB(s)c, which indicates a bar structure across the core (SAB), no ring (s), and loosely wound spiral arms. The inner part of the galaxy has two spiral arms, which branch into multiple arms further away. The small nucleus is of type HII, meaning the spectrum resembles that of an H II region.
During 1999, the Hubble Space Telescope was used to observe Cepheid variable stars in NGC 4535. The period-luminosity relationship for these objects yielded a distance modulus of 31.02 0.26 magnitude. This corresponded to a physical distance estimate of 52.2 6.2 Mly (16.0 1.9) Mpc, which was consistent with distance estimates for other members of the Virgo Cluster.

NGC 4526 (also listed as NGC 4560) is a lenticular galaxy with an embedded dusty disc, located approximately 55 million light-years from the Solar System in the Virgo constellation and discovered on 13 April 1784 by William Herschel.
The galaxy is seen nearly edge-on. The morphological classification is SAB(s)0, which indicates a lenticular structure with a weak bar across the center and pure spiral arms without a ring. It belongs to the Virgo cluster and is one of the brightest known lenticular galaxies. In the galaxy's outer halo, globular cluster orbital velocities indicate abnormal poverty of dark matter: only 4318% of the mass within 5 effective radii.
The inner nucleus of this galaxy displays a rise in stellar orbital motion that indicates the presence of a central dark mass. The best fit model for the motion of molecular gas in the core region suggests there is a supermassive black hole with about 4.5+4.2
−3.0108 (450 million) times the mass of the Sun. This is the first object to have its black-hole mass estimated by measuring the rotation of gas molecules around its centre with an astronomical interferometer (in this case the Combined Array for Research in Millimeter-wave Astronomy).
Supernova SN 1969E was discovered in this galaxy in 1969, reaching a peak magnitude of 16. In 1994, a Type 1a supernova was discovered about two weeks before reaching peak brightness. Designated SN 1994D, it was caused by the explosion of a white dwarf star composed of carbon and oxygen.

Scope: 12.5" Planewave CDK
Camera: Apogee U16M w GenII Astrodon LRGB
Mount: Paramount ME (MKS5000)

Exposures: 6/11/9/8 x 10 minutes LRGB

Processed in PixInsight and Photoshop CC as follows:
PixInsight:
- WBPP script for LRGB masters
- RGB combine
- Russ Croman's BlurXTerminator on L and RGB unstretched masters
- Russ Croman's NoiseXTerminator on both
- SPCC colour calibration on RGB
- Curves and HistogramTransformation on both
Photoshop:
- adjustments to background and colour balance done "to taste"
- minor cleanup

Lucknow, Ontario
April 2023

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