Welcome back to Messier Monday! Today, we continue in our homage to our dear good friend, Tammy Plotner, by taking a look at the Southern Pinwheel Galaxy– likewise called Messier 83!
Throughout the 18 th century, famous French astronomer Charles Messier saw the existence of numerous “ambiguous things” while surveying the night sky. Initially misinterpreting these things for comets, he started to brochure them so that others would not make the exact same error. Today, the resulting list (called the Messier Brochure) consists of over 100 things and is among the most prominent brochures of Deep Area Objects.
Among these things is the Southern Pinwheel Galaxy (aka. Messier 83), a disallowed spiral nebula situated 15.21 million light years from Earth in the southern constellation Hydra With a spatial size of about 55,000 light years, or approximately half the size of the Galaxy, M83 is among the nearby and brightest disallowed spirals in the sky.
M83 is categorized as someplace in between an intermediate and regular disallowed spiral nebula with well formed spiral arms, dust lanes, a main bar and strong nucleus … Yet filled with faint functions. As David Malin (et al.) suggested in a 1997 research study:
” Here we provide examples of gas-rich galaxies without apparent interactions or buddies that nevertheless reveal proof of interaction. A close-by example is NGC 253, in the Carver group. The degree of the optical halo of this galaxy is much higher than that of the neutral hydrogen envelope identified by Koribalski et al. (1995), and it likewise extends well beyond the fields where Hawthorn has actually identified scattered H-alpha emission (unpublished). The low surface area brightness envelope is lacking great information and is uncommon in not being highly truncated, as holds true for the majority of spirals. Nevertheless, it likewise reveals an unique, unbalanced extension in the southern half of the galaxy. This is hard comprehend, considering that NGC 253 is not undoubtedly connecting with other members of the Carver group, and no other structures in the disk of the galaxy, or in the HI speed profile, recommend any type of external disruption.”
However it is what’s taking place internally towards the nucleus that bears fantastic research study. As Debra Elmegreene (et al) suggested in a 2007 research study:
” Our (J-K) color observations of the main areas of the starburst galaxy M83 expose a double circumnuclear ring. The primary dust lanes spiral into the external nuclear ring at a radius of 150 pc. The 2 rings might accompany 2 inner Lindblad resonances. The primary locations happen in an arc that is in between the rings. A dust bar that is balanced out 90 ° from the main excellent bar links the external nuclear ring to the inner nuclear ring at a radius of 50 pc and might supply the course for gas to stream to the main starburst.”
And it is the main starburst activity that thrills. As S. Ryder (et al) stated in their 2004 research study:
” The circumnuclear starburst in NGC 5236 (M 83) has actually been studied photometrically by Harris et al. (2001) utilizing HST/WFPC2 images in the broad-band near-UV and optical, along with narrow-band Ha and Hb to obtain colors and line comparable widths for 45 clusters. Regardless of the outstanding spatial resolution of these observations, optical photometric analyses such as this struggle with: (i) patchy (and not quickly measurable) dust termination; (ii) the reality that the reddening vector parallels the evolutionary tracks in a two-color diagram; and (iii) choice results, which tend to omit the really youngest (t < 5 Myr) clusters which have strong emission lines, however just a weak excellent continuum. Furthermore, it is not possible to identify an instant burst of star development from a consistent star development rate, on the basis of broad-band colors alone."
Among Messier 83’s most uncommon qualities is the impressive variety of supernovae occasions tape-recorded in simply the last century. As Christopher Stockdale (et al) suggested in a 2006 research study:
” We report the outcomes of 15 years of radio observations of the 6 historic supernovae (SNe) in M83 utilizing the Huge Selection. We keep in mind the near-linear decrease in radio emission from SN 1957 D, a Type II SN, which stays a nonthermal radio emitter. The determined flux densities from SNe 1923 A and 1950 B have actually flattened as they start to fade listed below noticeable limitations; they are likewise Type II SNe. The luminosities for these 3 SNe are equivalent with the radio luminosities of other decades-old SNe at comparable dates. SNe 1945 B, 1968 L, and 1983 N were not identified in the most current observations, and these nondetections follow previous research studies. We report the X-ray nondetections of all 6 historic SNe utilizing the Chandra X-Ray Observatory, constant with previous X-ray searches of other decades-old SNe and low presumed mass-loss rates of the progenitors.”
History of Observation:
M83 was found by Abbe Nicholas Louis de la Caille at the Cape of Excellent Hope on February 23, 1752 and was the very first outside our Resident Group to be cataloged. Regardless of its really low position for Paris, it was next cataloged by Charles Messier on February 17, 1781 who stated:
” Nebula without star, near the head of Centaurus: it looks like a faint and even radiance, however it is hard to see in the telescope, as the least light to brighten the micrometer wires makes it vanish. One is just able with the best concentration to see it at all.”
Although it would be identified by Sir William Herchel, it was his child John who would later on compose from the Cape of Excellent Hope:
” Extremely intense; large; unexpectedly brighter towards the middle to a centre looking like a star of 9 m, size 8 ″, of a resolvable character like a globular cluster, surrounded by a profoundly big, incredibly water down nearly equable light 7 ′ or 8 ′ diam, rather oval, and passing with an extreme suddenness into the main light.”
Finding Messier 83:
Due To The Fact That of Messier 83’s low southern position, it is rather hard to discover in the northern hemisphere, regardless of it’s magniude and size. Start by indentifying Gamma or Pi Hydrae. From Gamma it has to do with a fistwidth northwest from Pi about a fistwidth southwest. If you remain in the southern hemisphere, find Iota and Theta Centauri and merely starhop 1, 2, 3, 4, 5 to M83 From the north it will need a minimum of a 3-4 ″ telescope and dark skies, while southerns can identify it quickly with little field glasses.
Wanting you luck in discovering it!
Things Call: Messier 83
Alternative Classifications: M83, NGC 5236, Southern Pinwheel Galacy
Things Type: SABc Spiral Nebula
Right Ascension: 13: 37.0 (h: m)
Declination: -29: 52 (deg: m)
Range: 15000 (kly)
Visual Brightness: 7.6 (mag)
Obvious Measurement: 11 X10(arc minutes)
We have actually composed numerous fascinating posts about Messier Objects and globular clusters here at Universe Today. Here’s Tammy Plotner’s Intro to the Messier Things, M1– The Crab Nebula, Observing Spotlight– Whatever Occurred to Messier 71?, and David Dickison’s posts on the 2013 and 2014 Messier Marathons.