Monthly Observer’s Challenge

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

June 2021

NGC 5746, Galaxy in Virgo

Sharing Observations and Bringing Amateur Astronomer’s Together

MONTHLY OBSERVER’S CHALLENGE

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This month’s target

William Herschel discovered NGC 5746 on 24 February 1786 with his 18.7-inch reflector. His handwritten journal reads:” Extremely bright, much extended in the parallel, 8 or 9 arcminutes long, bright nucleus.”

A recent study by John Kormendy and Ralf Bender in the Astrophysical Journal presents NGC 5746 as a structural analog of our own galaxy. Both are “are giant, SBb–SBbc galaxies with two pseudobulges, i.e., a compact, disky, star-forming pseudobulge embedded in a vertically thick, ‘red and dead,’ boxy pseudobulge that really is a bar seen almost end-on.” According to the authors, the lives of these galaxies have been dominated by minor mergers and bar-driven evolution for most of the history of the universe. They place NGC 5746 at a distance of 26.7 Mpc (87 million light-years). https://ui.adsabs.harvard.edu/#abs/2019ApJ…872..106K/abstract

NGC 5746’s V(V_T) visual magnitude is 10.32 ± 0.13, and its surface brightness is 12.6. The galaxy’s visible extent through medium-size amateur telescopes under dark skies is in the vicinity of 7.4′ × 1.3′.