Free Astronomy Magazine May-June 2021

40 MAY-JUNE 2021 Deep dive into a galaxy cluster A stronomers refer to observa- tions as “deep” when they are taken with very long ex- posure times. Just as with photogra- phy, this gathers more light, reveal- ing distant, fainter objects. Deeper exposures let astronomers look deeper into the Universe — hence the name. This particular deep image (right) was taken with a 70- minute exposure with the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory, a Pro- gram of NSF’s NOIRLab, and captures the spiral galaxy NGC 1003. NGC 1003 lies over 30 million light- years from Earth in the direction of the constellation Perseus. While it by NOIRLab - Amanda Kocz Z ooming on NGC 1003 for press release noirlab2101: Deep Dive into a Galaxy Cluster. [KPNO/NOIR- Lab/NSF/AURA, S. Brunier/Digitized Sky Survey 2, E. Slawik. Image Pro- cessing: Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin] A stunning long-exposure obser- vation lasting 70 minutes from the Nicholas U. Mayall 4-meter Tele- scope at Kitt Peak National Observa- tory, a Program of NSF’s NOIRLab, reveals the spiral galaxy NGC 1003 in glorious detail. NGC 1003 resides in front of a galaxy cluster — a vast col- lection of galaxies bound together by gravity. The long exposure time of this deep observation allowed these usually overlooked red background cluster galaxies to be captured. [KPNO/NOIRLab/NSF/AURA - Ack: M.T. Patterson (New Mexico State Univer- sity) - Image processing: Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin] makes for a spectacular sight, it is only one of many galaxies captured in this image. Upon closer inspec- tion, other galaxies can also be seen strewn throughout the image, with everything from delicate spiral gal- axies to hundreds of fuzzy, red ellip-