[APOD]사자자리 세 천체(2017.4.12.)

사자자리 세 천체

이 그룹은 북반구 봄에 꽤 유명합니다. 사자자리 세쌍둥이(Leo Triplet)로서 유명하며, 세 개의 근사한 은하들이 한 시야에 모여 있습니다. 그다지 대단하지 않은 망원경으로 관측해도 잘 보이며, 이것들은 NGC 3628(왼쪽)과 M66(오른쪽 아래) 그리고 M65(위)로 각각 나뉩니다. 세 개 모두 거대 나선 은하이지만, 비슷하게 보이지는 않습니다. 그 이유는 그들의 은하면이 우리의 시선방향에 서로 다른 각도로 기울어져 있기 때문입니다. NGC 3628은 측면이 보여 지며, 은하평면을 가로지르는 먼지 띠에 의한 차폐 모습도 관찰됩니다. 반면 M66과 M65는 둘 다 나선 구조가 보일만큼 충분히 기울어져 있습니다. 그룹 내 은하 간 중력적 상호작용 또한 숨길 수 없는 흔적을 보여주고 있는데, NGC3628의 비틀어지고 부풀어진 디스크, 그리고 M66의 끌리는 나선팔이 이에 포함됩니다. 멋진 모습의 이 영역은 하늘에서 약 1도(2개의 보름달 각크기)를 차지합니다. 이 영역은 이 셋의 추정된 거리인 3천만 광년에서 50만광년의 크기를 차지하고 있습니다.

원문출처: https://apod.nasa.gov/apod/ap170412.html

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 April 12

Leo Trio
Image Credit & Copyright: Ignacio Diaz Bobillo

Explanation: This group is popular in the northern spring. Famous as the Leo Triplet, the three magnificent galaxies gather in one field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (left), M66 (bottom right), and M65 (top). All three are large spiral galaxies but they tend to look dissimilar because their galactic disks are tilted at different angles to our line of sight. NGC 3628 is seen edge-on, with obscuring dust lanes cutting across the plane of the galaxy, while the disks of M66 and M65 are both inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the group have also left telltale signs, including the warped and inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans about one degree (two full moons) on the sky. The field covers over 500 thousand light-years at the trio's estimated distance of 30 million light-years.