Hubble Is Back In Business

These images are among the first from Hubble after its return to full science operations. On the left is ARP-MADORE2115-273, a rarely observed example of a pair of interacting galaxies. On the right is ARP-MADORE0002-503, a large spiral galaxy with unusual spiral arms. Most disk galaxies have an even number of spiral arms, but this one has three.

Image Credits: Science—NASA / ESA / STScI / Julianne Dalcanton (UW)
Image processing—Alyssa Pagan (STScI)

A Pair of Different Galaxies

This image taken with Hubble’s Wide Field Camera 3 shows a pair of dissimilar galaxies. The one in the upper left is the lenticular galaxy cataloged as 2MASX J03193743+4137580. The spiral galaxy in the lower right has the shorter designation of UGC 2665. They’re both about 350 million light-years away.

Image Credit: NASA / ESA

Warp Factor

How did spiral galaxy ESO 510-13 get bent out of shape? The disks of many spiral galaxies are thin and flat, but with the gaps between star they are not solid. Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center. The common flat disk shape  is thought to be created by sticky collisions of large gas clouds early in the galaxy’s formation. Warped disks are not uncommon, though, and even our own Milky Way Galaxy is thought to have a bit of warp. The causes of spiral warps are still being investigated, but some warps are thought to result from interactions or even collisions between galaxies. ESO 510-13, shown in the digitally sharpened Hubble image above, is about 150 million light years away and about 100,000 light years across.

Image Credit: NASA

NGC 300

ngc 300NGC 300 is a spiral galaxy in the constellation Sculptor. At one time, it was thought that NGC 300 was a part of a galaxy cluster know as th eSculptor Group. However, recent measurements show that it is closer to us in the relatively empty space between our Local Group and the Sculptor Group. It’s about 94,000 light-years in diameter, somewhat smaller than the Milky Way

Image Credit: ESO

A Cosmic Bullseye

This false color image of galaxy NGC 1921 was taken in infrared light by the Spitzer Space Telescope. The outer red ring is filled with new stars that are igniting and heating up surrounding dust which glows in infrared light. The stars in the center of the galaxy produce shorter-wavelength infrared light which is color-coded blue. The old stars in the center have long ago gobbled up the available gas supply, the fuel for making new stars.

NGC 1921 is roughly 12 billion years old. It is known as a barred galaxy because a central bar of stars (which appears as a blue S in this view) dominates its center. When barred galaxies are young and gas-rich, the stellar bars draw gas toward the center, feeding star formation there. As that star-making fuel runs out, the central regions calm down, and star-formation activity moves to the outskirts of a galaxy. There, spiral density waves and resonances induced by the central bar help gas coalesce into stars. The red outer ring is such s resonance location, where gas is being trapped and new stars ignited.

Image Credit: NASA

A Distorted Spiral

A galactic maelstromThis is Messier 96, a spiral galaxy a bit more than 35 million light-years away in the constellation of Leo (The Lion). It is roughly the same mass and size as the Milky Way, but unlike our more or less symmetrical galaxy, M96 is lopsided. Its dust and gas are unevenly spread throughout its weak spiral arms, and its core is not exactly at the apparent galactic center. Its arms are also asymmetrical, perhaps because of the gravitational pull of other galaxies within the same group as Messier 96.

Image Credit: ESA / NASA

M61

M61Messier 61 is a type of galaxy known as a starburst galaxy. Starburst galaxies have an abnormally high rate of star formation, hungrily using up their reservoir of gas in a very short period of time (in astronomical terms). However, that’s not the only activity we believe is going on within M61; deep at its heart there is thought to be a supermassive black hole that is violently spewing out radiation.

Despite its inclusion in the Messier Catalogue, Messier 61 was actually discovered by Italian astronomer Barnabus Oriani in 1779. Charles Messier also noticed this galaxy on the very same day as Oriani, but mistook it for a comet.

Image Credit: NASA

NGC1288

FORS1 First Light - Spiral galaxy NGC 1288This is the spiral galaxy NGC 1288 in the southern constellation Fornax. The distance to this galaxy is about 300 million light-years, and it is receding from us at around of 4500 km/s. It’s roughly 200,000 light-years or about twice the diameter of the Milky Way.

Image Credit: ESO

NGC 4689

NGC 4689 is a spiral galaxy located about 54 million light-years away in the constellation of Coma Berenices and a member of the Virgo Cluster of galaxies.

The galaxy’s star forming disk has been truncated which has caused the amount of star formation to be significantly reduced. The truncation may have been the result of interaction with other galaxies in the Virgo Cluster which caused the galaxy to lose much of its interstellar gas and dust, the fuel for new star formation. NGC 4689 has been classified as an Anemic galaxy because its lack of material for making new stars.

Image Credit: NASA / ESA

NGC 5468

We see the galaxies around us in various orientations. NGC 5468 is a spiral galaxy which we see with an almost dead-on top-down view. Over the last couple of decades, NGC 5468 has hosted a number of supernovae: SN 1999cp, SN 2002cr, SN2002ed, SN2005P and SN2018dfg. Despite being just over 130 million light-years away, the  face-on orientation of the galaxy with respect to us makes it easier to spot such new “stars” as they appear.

Image Credit: NASA / ESA