Messier 100

Bildtafel Messierobjekte.jpg
Autor/Urheber:

diverse

, Lizenz: CC-by 3.0
Bildtafel der 110 Messier-Objekte.

Messier 100 - GALEX - wikisky.png
NGC 100 by GALEX

Messier100 - ESO - Potw1917a.jpg
Autor/Urheber: Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton, Lizenz: CC BY 4.0
Starbursts and slow burns

This is one of 74 nearby galaxies whose stellar nurseries were recently observed by the Atacama Large Millimeter/submillimeter Array, or ALMA, in an astronomical census called Physics at High Angular resolution in Nearby GalaxieS (PHANGS). So far, around 100 000 of these stellar nurseries have been imaged in over 750 hours of observation. ALMA’s remarkable sensitivity provides data at high enough resolution to study these regions in detail, and shows that some are bursting with new stars, while others evolve more gradually.

This anticipated diversity in the process of how stars form was the motivation behind this enormous effort. There have long been theories that aimed to explain how and why these differences might occur, some involving the characteristics of the home galaxy itself — properties such as size, age, and internal dynamics — but our lack of high-resolution data had been an obstacle to testing them.

The vast quantity and variety of data yielded by PHANGS are already helping astronomers to understand more, even though the census is only a third complete. The project aims to observe a total of about 300 000 stellar nurseries and by the end it should significantly advance our understanding of how a galaxy’s properties influence the way in which it forms new stars.

Credit:

ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

Coordinates
Position (RA): 	12 22 54.26
Position (Dec):	15° 49' 20.09"
Field of view: 	4.00 x 3.55 arcminutes
Orientation:   	North is -0.0° left of vertical

Colours & filters
Band   	Wavelength	Telescope
Infrared Y	1.021 μm	Very Large Telescope HAWK-I
Infrared J	1.258 μm	Very Large Telescope HAWK-I
Infrared H	1.62 μm 	Very Large Telescope HAWK-I
Infrared Ks	2.146 μm	Very Large Telescope HAWK-I
Millimeter CO(2-1)	1.2 mm	Atacama Large Millimeter/submillimeter Array Band 6

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Messier 100 and Supernova SN 2006X.jpg
Autor/Urheber: ESO/IDA/Danish 1.5 m/R. Gendler, J.-E. Ovaldsen, C. C. Thöne and C. Féron, Lizenz: CC BY 4.0
Similar in appearance to our own Milky Way, Messier 100 is a grand spiral galaxy that presents an intricate structure, with a bright core and two prominent arms. The galaxy harbours numerous young and hot massive stars as well as extremely hot regions of ionised hydrogen. Two smaller arms are seen emerging from the centre and reaching towards the larger spiral arms. The galaxy, located 60 million light-years away, is slightly larger than the Milky Way, with a diameter of about 120,000 light-years. A supernova was discovered in M100 on 4 February 2006. Named SN 2006X, it is the 5th supernova to have been found in M100 since 1900. This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 1390 s, V: 480 s, R: 245 s). The supernova is the brighter of the two stars seen just to the lower right of the galaxy centre.

25 years of stunning definition Messier 100.jpg
(c) ESA/Hubble, CC BY 4.0
This stunning spiral galaxy is Messier 100 in the constellation Coma Berenices, captured here by the NASA/ESA Hubble Space Telescope — not for the first time. Among Hubble’s most striking images of Messier 100 are a pair taken just over a month apart, before and after Servicing Mission 1, which took place 25 years ago in December 1993.

After Hubble was launched, the astronomers and engineers operating the telescope found that the images it returned were fuzzy, as if it were out of focus. In fact, that was exactly what was happening. Hubble’s primary mirror functions like a satellite dish; its curved surface reflects all the light falling on it to a single focal point. However, the mirror suffered from a defect known as a spherical aberration, meaning that the light striking the edges of the mirror was not travelling to the same point as the light from the centre. The result was blurry, unfocused images.

To correct this fault, a team of seven astronauts undertook the first Servicing Mission in December 1993. They installed a device named COSTAR (Corrective Optics Space Telescope Axial Replacement) on Hubble, which took account of this flaw of the mirror and allowed the scientific instruments to correct the images they received. The difference between the photos taken of Messier 100 before and after shows the remarkable effect this had, and the dramatic increase in image quality.

COSTAR was in place on Hubble until Servicing Mission 4, by which time all the original instruments had been replaced. All subsequent instrumentation had corrective optics built in.

This new image of Messier 100 taken with Hubble’s Wide Field Camera 3 (WFC3), demonstrates how much better the latest generation of instruments is compared to the ones installed in Hubble after its launch and after Servicing Mission 1.